Assessments of technological developments:
Best available techniques (BAT) and limit values
Final Draft
Prepared by:
Katja Kraus (Chair, Germany)
Stefan Wenzel (Germany)
Grace Howland (Canada)
Ute Kutschera (Austria)
Stanislaw Hlawiczka (Poland)
André Peeters Weem (The Netherlands)
Chuck French (United States of America)
Submitted to the Task Force on Heavy Metals
UNECE Convention on Long-range Transboundary Air Pollution
June 14, 2006
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2
Executive summary
1.
The following overview of the most recent technological BAT developments in relation to
annex III of the Protocol covers both new and existing stationary sources and is given for each
source category as indicated in annex III. Additional information is given for emerging technologies. Techniques already described in annex III are not taken into account for this summary.
Further information on techniques with regard to application, environmental performance etc.,
can be found in the respective chapters.
2.
The primary sources of information for this document were the BAT reference documents
from the European Integrated Pollution Prevention and Control Bureau (EIPPCB). Other
sources of information included the United Nations Environment Program (UNEP) 2002 Global
Mercury Assessment, and various technical reports from United States Environmental Protection Agency (U.S. EPA), Environment Canada, and the European Commission. References
relevant to each chapter are provided at the end of the individual chapters. There may by other
sources of information that were not considered.
Table 1:
Overview on Most Recent Developments with BAT and other Emissions Control Techniques
Sector
BAT according to BREF documents and potential BAT
from other references
Emerging Techniques
Combustion
of fossil fuels
in utility and
industrial
boilers
Stable combustion conditions (reduce peak emissions)
Wet FGD plus particulate matter (PM) control device (ESP or
FF) (plus high dust SCR)
Injection of sorbent prior to FGD
Carbon filter bed filtration of flue gas
For low sulfur fuels (e.g. biomass):
FF
For combustion of coal:
IGCC
New designs of ESPs
Improving the liquid-togas ratio
Wet FGD Tower Design
Injection of activated
carbon impregnated
with additives
Low-NOx technologies
(BAT for NOx-control)
Reburning (BAT for
NOx-control)
Simultaneous control of
sulfur dioxide, nitrogen
oxides and Hg
Fuel cells
Biomass-fired IGCC
Primary iron
and steel
industry
Efficient capture and exhaust of emissions
Processing of ferrous metal ores
Increase the mercury rejection to the tailing
Sinter plants
Fine wet scrubbers or FF with lime addition
Exclusion of PM from last ESP field from recycling to the sinter
strand
Recirculation of waste gas
Pelletisation plants
Scrubbing
Semi-dry desulfurization and subsequent PM removal
Blast furnaces
Direct reduction/ smelting reduction (alternatives to the coke oven/BF route)
Blast furnaces
Continuous steelmaking
Basic oxygen steelmaking and casting
New reagents in the
desulfurization process
Foaming techniques at
pig iron pre-treatment
and steel refining
3
Hot stoves
Cast house PM removal
Basic oxygen furnaces:
Minimize the presence of mercury in the scrap by removing
mercury-bearing components
Secondary
Minimize the presence of mercury in the scrap by removing
iron and
mercury-bearing components
steel industry Electric arc furnace
Direct off gas extraction
Capture and control of charging and tapping emissions, e.g.,
canopy hood and baghouse)
Iron foundries
Minimizing fugitive emissions
Cupola furnace melting of cast iron
Improve the thermal efficiency
Divided blast operation (2 rows of tuyères) for cold blast cupolas
Oxygen enrichment of the blast air
Minimize the blast-off periods for hot blast cupolas
Induction furnace melting of cast iron and steel
Increase furnace efficiency
Dry flue-gas cleaning
Rotary furnace melting of cast iron
Increase the melting efficiency
Post combustion
Dry PM removal
Primary and
secondary
non-ferrous
metal industry
Minimize emissions from materials handling, storage and transfer
Sealed reactors and furnaces
Processes connected to a sulfuric acid plant:
Wet scrubber or wet ESP
Removal of mercury from off-gas
Activated carbon filter
Spray dry systems with downstream FF
Removal of mercury from sulfuric acid
Superlig Ion Exchange process
Potassium iodide process
Primary and secondary production of copper
Various processes depending on raw materials
FF (with lime injection)
Scrubbing (if necessary)
Secondary production of aluminium
Various processes depending on raw materials
FF or ceramic filter
Primary and secondary production of lead and zinc
Various processes depending on raw materials
FF /wet ESP /wet scrubbing (depending on process)
Production of gold
FF / wet ESP / scrubbing (depending on process)
4
Electric arc furnace
Comelt EAF / Contiarc
furnace / Direct reduction / Liquid iron
Selenium filter
Odda chloride process
Primary and secondary
production of copper
Bath smelting
ISA Smelt
hydro-metallurgical processes (e.g. leachsolvent extractionelectro-win (L:SX:EW)
process)
Secondary production of
aluminium
Reuse of filter PM
Catalytic filter bags
Primary and secondary
production of lead and
zinc
Leaching processes
based on chloride
Injection of fine material
EZINEX process (direct
treatment of EAF dusts)
Direct smelting
Production of mercury
Phase out primary production of mercury
Stop surpluses re-entering the market
Production of mercury from secondary raw materials
Mercury scrubber (Boliden, thiosulphate etc).
Lead sulfide process
BSN process using PM
from EAF
Production of gold
'J' process
Gold production from
pyrite concentrate
Production of mercury
Process with abatement
of fine mercury particles
Cement industry
Dry process kiln with multi-stage preheating and precalcination
Fluidised bed cement
manufacturing
Lower exhaust temperature
Adsorption on activated
carbon
Glass industry
ESP or FF (with dry or semi-dry acid gas scrubbing)
Dry Injection FF/ Dry Lime Scrubber combination, or wet
scrubber
Minimize downstream emissions
Plasma melter
Chlor-alkali
industry
PARCOM decision 90/3 of 14 June 1990 (phase-out of the
mercury process) was reviewed in 1999-2001 without any
changes
Conversion to membrane cell technology
Non-asbestos diaphragm technology
Stop surplus of Hg from decommissioning re-entering the market
Minimizing emissions from handling, storage, treatment and
disposal of mercury-contaminated wastes
Stringent work place practices to reduce emissions, including:
1. Use of specific equipment (e.g., smooth interior pipes, fixed
covers, head space routed to ventilation system etc....
2. Preventive Operations (e.g., cool electroplate and decomposer before opening, keep mercury covered with aqueous
liquid at temperature below its boiling point, gas stream
cooling to remove mercury from hydrogen stream
Mist eliminators
Scrubbers
Adsorption on activated carbon and molecular sieves
Complete enclosure of the cell room
Municipal,
medical and
hazardous
waste incineration
In some countries, no differentiation between municipal, hazardous and medical waste in terms of applied techniques or
achievable emission limits.
Separate collection and treatment of mercury-containing
wastes
Substitution of mercury in products
Sorbent injection
FGD
Carbon filter beds
Wet scrubber with additives
5
Heavy metal evaporation process
Hydro-metallurgical
treatment + vitrification
Municipal waste incineration
PECK combination process
Selenium filters
Activated carbon injection prior to the ESP or FF
Activated carbon or coke filters
Selective catalytic reduction (SCR)
Co-incineration of waste and recovered fuel in cement kilns
Avoid Hg entering as an elevated component of the secondary
fuel
BAT for cement kilns
Co- incineration of waste and recovered fuel in combustion
installations
Avoid Hg entering as an elevated component of the secondary
fuel
Gasification of the secondary fuel
Injection of activated carbon
BAT for combustion installations
Definition of Acronyms used in Table 1:
BAT
Best available techniques
BF
Blast furnace
BOF
Basic oxygen furnace
BREF
Best available technique reference document
CFA
Circulating fluidized-bed absorber
EAF
Electric arc furnace
ESP
Electrostatic precipitator
FF
Fabric filter
FGD
Flue gas desulfurization
IGCC
Integrated gasification combined-cycle
PM
Particulate matter
SCR
Selective Catalytic Reduction
3.
The following overview of the most recent technological ELV developments in relation to
annex V of the Protocol covers both new and existing stationary sources and is given for each
source category as indicated in annex III. Additional information is given for source categories
identified in annex II and heavy metals indicated in annex I of the Protocol for which no ELV is
specified in annex V. The current ELVs of annex V are given for comparison, as well as emission levels associated with best available techniques (BAT) from the European BREF documents which are not considered as ELVs. Most sectors cover a wide range of installations with
regard to technology and size, and the indicated ranges often comprise several techniques
and/or size classes. ELVs for heavy metals are often given for a whole range of heavy metals,
so the indicated values may not reflect an ELV for a single pollutant. Additionally, a combination of techniques might be necessary to achieve the indicated BAT associated emission levels. For further information, reference is made to the background information.
4.
All values are expressed in mg/Nm³, except for the chlor-alkali industry, where values are
expressed in g Hg/Mg Cl2 production capacity. All values refer to standard conditions (273.15
K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods.
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Table 2:
Overview on ELVs
Sector
Pollutant
Combustion PM
of fossil fuels
in utility and
industrial
boilers (> 50
MW, solid
and liquid
fuels)
ELVs
Annex V
ELVs in force (new installations)
ELVs in force (existing installations)
BAT (50 – 300 MW, new installations)
BAT (50 – 300 MW, existing installations)
BAT (> 300 MW, new installations)
BAT (> 300 MW, existing installations)
50
17-50
20-150
5-20
5-30
5-10
5-20
Cd
ELVs in force
0.05-1.1
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.01-0.2
PM
sinter plants Annex V
ELVs in force
BAT
50
20-150
10-50
pellet plants Annex V
ELVs in force
BAT
25
20-150
< 10
blast furnace Annex V
ELVs in force
BAT
50
6.8-150
1-15
other processes ELVs in force
BAT
5-150
5-30
Cd
ELVs in force
0.05-0.2
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.05-0.2
Secondary
PM
iron and
steel industry
EAF > 2.5 t Annex V
ELVs in force
BAT
20
5-20
< 5-15
other processes ELVs in force
20-50
Cd
ELVs in force
0.05-0.2
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.05-0.2
PM
ELVs in force
BAT
2.3-50
5-20
Cd
ELVs in force
0.05-0.2
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.05-0.2
Primary iron
and steel
industry
Iron foundries
7
Primary and
secondary
non-ferrous
metal industry
Cement industry
Glass industry
Chlor-alkali
industry
PM
production of Annex V
copper and zinc ELVs in force
BAT
20
1-50
1-5
production of lead Annex V
ELVs in force
BAT
10
1-50
1-5
production. of gold ELVs in force
BAT
1-50
1-5
production of mercury ELVs in force
BAT
1-50
1-5
other processes ELVs in force
5-50
Cd
ELVs in force
0.05-0.2
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.05-0.2
PM
Annex V
ELVs in force
BAT
50
15-150
20-30
Cd
ELVs in force
0.05-0.2
Pb
ELVs in force
0.5-5
Hg
ELVs in force
0.05-0.2
PM
ELVs in force
BAT
5-50
5-30
Cd
ELVs in force
0.05-5
Pb
Annex V
ELVs in force
BAT
5
0.5-5
<5
Hg
ELVs in force
0.05-0.2
Hg
new Annex V
installations ELVs in force
0.01
0.0-0.01
existing ELVs in force (legally binding phase out of mercury process) 1 installations 5.3
BAT (total emissions) (phase out of mercury process) 0.21-0.32
8
Municipal,
medical and
hazardous
waste incineration
PM
Cd
Pb
Hg
municipal waste Annex V
incineration > 3t/h ELVs in force
BAT
25
5-50
1-5
medical waste Annex V
incineration > 1t/h ELVs in force
BAT
10
5-30
1-5
hazardous waste Annex V
incineration > 1t/h ELVs in force
BAT
10
2.4-57
1-5
co-incineration ELVs in force
10-20
municipal waste ELVs in force
incineration > 3t/h BAT
0.03-0.2
0.005-0.05
medical waste ELVs in force
incineration > 1t/h BAT
0.028-0.2
0.005-0.05
hazardous waste ELVs in force
incineration > 1t/h BAT
0.05-0.5
0.005-0.05
co-incineration ELVs in force
0.05
municipal waste ELVs in force
incineration > 3t/h BAT
0.31-5
0.005-0.5
medical waste ELVs in force
incineration > 1t/h BAT
0.05-5
0.005-0.5
hazardous waste ELVs in force
incineration > 1t/h BAT
0.5-5
0.005-0.5
co-incineration ELVs in force
0.5
municipal waste Annex V
incineration > 3t/h ELVs in force
BAT
0.08
0.02-0.2
0.001-0.02
medical waste ELVs in force
incineration > 1t/h BAT
0.02-0.39
0.001-0.02
hazardous waste Annex V
incineration > 1t/h ELVs in force
BAT
0.005-0.2
0.001-0.02
co-incineration ELVs in force
0.03-0.05
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Table of contents
INTRODUCTION ................................................................................................. 13
COMBUSTION OF FOSSIL FUELS IN UTILITY AND INDUSTRIAL BOILERS ... 17
PRIMARY IRON AND STEEL INDUSTRY ........................................................... 27
SECONDARY IRON AND STEEL INDUSTRY .................................................... 35
IRON FOUNDRIES.............................................................................................. 41
PRIMARY AND SECONDARY NON-FERROUS METAL INDUSTRY ................. 47
CEMENT INDUSTRY .......................................................................................... 65
GLASS INDUSTRY ............................................................................................. 71
CHLOR-ALKALI INDUSTRY ................................................................................ 79
MUNICIPAL, MEDICAL AND HAZARDOUS WASTE INCINERATION ................ 85
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INTRODUCTION
5.
The Task Force on Heavy Metals reviewed technological developments with regard to
emissions from stationary sources for those heavy metals (HM) listed in annex I to the Protocol. This report compiles background information on technological developments for each
source category of annex II to the Protocol, including:
a compilation of recent developments in best available techniques (BAT) in relation to annex III to the Protocol;
a compilation of current emission limit values (ELVs) in relation to annex V to the Protocol
as well as for source categories identified in annex II and HM indicated in annex I for which
no ELV is specified in annex V.
6.
The report is structured according to the technical information given in annex III to the
Protocol. The following table gives an overview of the chapters of the report and their correspondence to the sector description and technical information in annex III and the source categories of annex II to the Protocol.
Table 3:
Coverage of sectors in this report
Sector
(chapter of
the report)
Technical information according to
annex III to the Protocol
Combustion
of fossil fuels
in utility and
industrial
boilers
Combustion of fossil fuels in utility and
industrial boilers: coal and fuel oil fired
boilers, not including gas turbines and
stationary engines, and not including
the use of waste as a fuel, are considered.
1: Combustion installations with a net rated
thermal input exceeding 50 MW
Primary iron
and steel
industry
Primary iron and steel industry: the
processing of ferrous metal ores together with the primary iron and steel
industry are considered. The production of mercury and gold as well as the
roasting and sintering of non-ferrous
metal ores are regarded within the
primary and secondary non-ferrous
metal industry.
2: Metal ore (including sulphide ore) or concentrate roasting or sintering installations with a
capacity exceeding 150 tonnes of sinter per
day for ferrous ore or concentrate, and 30
tonnes of sinter per day for the roasting of
copper, lead or zinc, or any gold and mercury
ore treatment.
Secondary
Secondary iron and steel industry: the
iron and
secondary iron and steel industry insteel industry cluding electric arc furnaces (EAF) are
considered.
Iron foundries
Source categories according to annex II to
the Protocol
3: Installations for the production of pig-iron or
steel (primary or secondary fusion, including
electric arc furnaces) including continuous
casting, with a capacity exceeding 2.5 tonnes
per hour.
Iron foundries: iron foundries, not in4: Ferrous metal foundries with a production
cluding steel and temper foundries, are capacity exceeding 20 tonnes per day.
considered.
13
Sector
(chapter of
the report)
Primary and
secondary
non-ferrous
metal industry
Technical information according to
annex III to the Protocol
Primary and secondary non-ferrous
metal industry: the processing of nonferrous metals and their ores is considered.
Source categories according to annex II to
the Protocol
5: Installations for the production of copper,
lead and zinc from ore, concentrates or secondary raw materials by metallurgical processes with a capacity exceeding 30 tonnes of
metal per day for primary installations and 15
tonnes of metal per day for secondary installations, or for any primary production of mercury.
6: Installations for the smelting (refining, foundry casting, etc.), including the alloying, of copper, lead and zinc, including recovered products, with a melting capacity exceeding 4
tonnes per day for lead or 20 tonnes per day
for copper and zinc.
Cement industry
Cement industry: the production of
cement clinker in fossil fuel fired kilns,
not including the use of waste as a
fuel, is considered.
7: Installations for the production of cement
clinker in rotary kilns with a production capacity
exceeding 500 tonnes per day or in other furnaces with a production capacity exceeding 50
tonnes per day.
Glass industry
Glass industry: the production of glass 8: Installations for the manufacture of glass
using lead in the process, including the using lead in the process with a melting capacrecycling of lead containing glass, is
ity exceeding 20 tonnes per day.
considered.
Chlor-alkali
industry
Chlor-alkali industry: the chlor-alkali
production by the mercury, diaphragm
and membrane cell electrolysis process is considered.
9: Installations for chlor-alkali production by
electrolysis using the mercury cell process..
Municipal,
medical and
hazardous
waste incineration
Municipal, medical and hazardous
waste incineration: the incineration of
municipal, medical and hazardous
waste is considered.
10: Installations for the incineration of hazardous or medical waste with a capacity exceeding 1 tonne per hour, or for the co-incineration
of hazardous or medical waste specified in
accordance with national legislation.
11: Installations for the incineration of municipal waste with a capacity exceeding 3 tonnes
per hour, or for the co-incineration of municipal
waste specified in accordance with national
legislation.
14
7.
The following acronyms are used throughout the document:
BAT
Best available techniques
BF
Blast furnace
BOF
Basic oxygen furnace
BREF
Best available technique reference document
CFA
Circulating fluidized-bed absorber
EAF
Electric arc furnace
EIPPCB
European Integrated Pollution Prevention and control Bureau
ELV
Emission limit values
ESP
Electrostatic precipitator
FF
Fabric filter
FGD
Flue gas desulfurization
IGCC
Integrated gasification combined-cycle
PM
Particulate matter
SCR
Selective Catalytic Reduction
8.
The primary sources of information for this document were the BAT reference documents
from the European Integrated Pollution Prevention and control Bureau (EIPPCB). Other
sources of information included the United Nations Environment Program (UNEP) 2002 Global
Mercury Assessment, and various technical reports from the US Environmental Protection
Agency (US EPA), Environment Canada, and the European Commission. References relevant
to each chapter are provided at the end of the individual chapters. There may by other sources
of information that were not considered.
15
16
COMBUSTION OF FOSSIL FUELS IN UTILITY AND INDUSTRIAL BOILERS
Background
9.
This category covers the combustion of fossil fuels in utility and industrial boilers. Annex II
of the Protocol limits the coverage to combustion installations with a net rated thermal input
exceeding 50 Megawatts (MW). According to Annex III, Best Available Techniques (BATs) are
considered for coal and fuel oil fired boilers.
10. The combustion of biomass and peat are not currently taken into account in annex III but
may be a relevant source of heavy metal emissions. Therefore, additional information is given
for these installations. The co-incineration of waste in combustion installations is treated within
the category municipal, medical and hazardous waste incineration.
11. According to Annex III, BAT to reduce emissions of heavy metals, except mercury, include the reduction in fuel use and the combustion of natural gas or alternative fuels with a low
heavy metal content, the use of electrostatic precipitators or fabric filters. Further emission reduction may be achieved by integrated gasification combined-cycle (IGCC) power plant technology, the beneficiation (washing or bio-treatment) of coal, and the application of techniques
to reduce emissions of nitrogen oxides, sulphur dioxide and particulates. No BAT for mercury
removal is identified in Annex III.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
12. About half of the electricity generated worldwide is produced from different fossil fuels,
with 30 % being generated from coal. The combustion process leads to the generation of emissions to air which are considered to be one of the major sources of air pollution. The emission
of heavy metals results from their presence as a natural component in fossil fuels and are
mostly released as compounds in association with particulates. Therefore, BAT to reduce the
emissions of heavy metals is generally the application of high performance dedusting devices
such as electrostatic precipitators or fabric filters. However, mercury is at least partly and up to
90 % present in the vapor phase and its collection by particulate matter control devices is highly variable. For electrostatic precipitators (ESPs) or fabric filters (FFs) operated in combination
with flue gas desulfurization (FGD) techniques, an average removal rate of 75 % and 90 % in
the additional presence of high dust Selective Catalytic Reduction (SCR) devices can be obtained for Hg, depending on the temperature of the filter system and the characteristics of the
combusted coal, e.g., char/carbon content, chlorine content, etc..
13. BAT for preventing releases of particulate matter (PM) from the unloading, storage and
handling of solid and liquid fuels and also additives such as lime and limestone are:
using loading equipment that minimises the height of fuel drop to the stockpile
using water spray systems for stockpiles, where applicable
covering stockpiles
grassing over long-term storage areas of coal
for lignite, the direct transfer via belt conveyors or trains from the mine to the storage area
placing transfer conveyers in safe areas aboveground so that they are not damaged
using cleaning devices for conveyer belts
17
-
using enclosed conveyers with well designed extraction and filtration equipment on transfer
points
rationalising transport systems
using good design and construction practices and adequate maintenance
for lime and limestone, having enclosed conveyers, pneumatic transfer systems and silos
with well designed extraction and filtration equipment on transfer points
Combustion of coal and lignite
14. For the fuel pretreatment of coal and lignite, blending and mixing of fuels can be part of
BAT, in order to ensure stable combustion conditions and to thus reduce peak emissions.
Switching fuel to a fuel with a better environmental profile can also be regarded as BAT. If coal
cleaning is carried out prior to combustion, data from the US Department of Energy indicate
that typically 10 – 50 % of the mercury in coal can be removed by the cleaning process alone.
The same sources indicate that removal of Cd and Pb can reach even 80%.
15. For the combustion of coal and lignite, pulverized combustion, fluidized bed combustion
as well as pressurized fluidized bed combustion and grate firing are all BAT for new and existing plants. Grate firing should preferably only be applied to new plants with a rated thermal input below 100 MW. Pressurized gasification in an integrated gasification combined-cycle
(IGCC) is a high efficiency technology that reduces emissions from large scale power production based on solid fuels. Power plants based on coal gasification have been in operation in the
USA since 1983 (Kingsport, Tennessee) and IGCC installations have been in use in the USA
since 1995 (Polk, Florida) and in the Netherlands since 1994 (Buggenum). Since then several
more installations have been commissioned in the USA and Europe. For more information see:
http://www.clean-energy.us.
16. For dedusting off-gases from coal- and lignite-fired new and existing combustion plants,
BAT is the use of an ESP or a FF, where a FF normally achieves emission levels below
5 mg/m³. Furthermore, the best levels of mercury control are generally achieved by emission
control systems (e.g. FGD plus particulate control device) that use FFs. Cyclones and mechanical collectors alone are not BAT, but they can be used as a pre-cleaning stage. BAT associated emission levels for dust are lower for combustion plants over 100 MW th, especially over
300 MWth, because the wet FGD technique which is already a part of the BAT conclusion for
desulphurisation also reduces particulate matter (PM).
17. All solid fuels such as coal and lignite have a certain concentration of trace elements such
as heavy metals. Basically most of the heavy metals evaporate in the combustion process and
condensate later onto the surface of the particulate matter (i.e. fly ash). Therefore, BAT to reduce the emissions of most heavy metals from flue-gases of coal- and lignite-fired combustion
plants is to use a high performance ESP (dust reduction rate >99.5%) or a FF (dust reduction
rate >99.95%, below 5 mg/m³). With mercury in particular, the capture efficiencies of these systems heavily depend on the speciation of the mercury in, and the fly ash content of, the flue
gas. Therefore, for some plants using high performance ESP or FF, the capture of mercury on
fly ash can be enhanced by switching or blending the combusted coals to achieve a higher
carbon/char, higher chlorine, or lower mercury content in the combusted coal or by introducing
carbon/activated carbon into the flue upstream of the ESP or FF.
18. Mercury has a high vapour pressure at the typical control device operating temperatures,
and its collection by particulate matter control devices is highly variable. Taking into account
that spray dryer FGD scrubbers and wet lime/limestone scrubbers are regarded as BAT for the
18
reduction of sulfur dioxide (SO2) for larger combustion plants, relatively low mercury (Hg)
emission levels can also be achieved. For the reduction and limitation of Hg emissions, the
best levels of control are generally obtained by emission control systems that use FFs and
ESPs, where high efficiency ESPs show good removal of Hg (bituminous coal) at temperatures
below 130 °C. It appears that little Hg can be captured in hot-side ESPs (installed upstream of
the air heater). The best levels of control are generally obtained by emission control systems
that use FFs. However, life time of fabric filters is very dependent upon the working temperature and their resistance to the chemical attack by corrosive elements in exhaust gases.
19. Dry FGD systems are already equipped to control emissions of SO2 and PM. Wet FGD
systems are typically installed downstream of an ESP or FF. Wet limestone FGD scrubbers are
the most commonly used scrubbers on coal-fired utility boilers. These FGD units are expected
to capture more than 90 per cent of the ionic mercury (Hg2+) in the flue gas entering the scrubber. Consequently, existing wet FGD scrubbers may lower Hg emissions between 20 and
80 %, depending on the speciation of Hg in the inlet flue gas. Improvements in wet scrubber
performance in capturing Hg depend primarily on the oxidation of elemental mercury (Hg 0) to
Hg2+. This may be accomplished by (i) the injection of appropriate oxidizing agents or (ii) the
installation of fixed oxidizing catalysts upstream of the scrubber to promote oxidation of elemental mercury Hg0 to water soluble species (such as Hg2+). An alternative strategy for controlling Hg emissions from wet FGD scrubbing systems is to inject sorbents upstream of the PM
control device. Wet scrubbers installed primarily for mercury cost between $76,000 and
$174,000 per pound of mercury removed.
20. For FFs or ESPs operated in combination with FGD techniques, such as wet limestone
scrubbers, spray dryer scrubbers or dry sorbent injection, an average removal rate of 75 % or
90 % in the additional presence of SCR can be obtained. The reduction rate when firing subbituminous coal or lignite is considerably lower and ranges from 30 – 70%. The lower levels of
Hg capture in plants firing sub-bituminous coal and lignite are attributed to the low fly ash carbon content and the higher relative amounts of gaseous Hg in the flue gas from the combustion
of these fuels.
21. Additional mercury control can be achieved by injection of a sorbent (carbon- and/or calcium-based) prior to the flue gas treatment system. The used carbon and attached waste products are captured by existing PM controls, such as electrostatic precipitators or baghouses.
The US test programs have shown mercury removals of 50 to over 95 percent, depending on
the carbon feed rate. The U.S. Environmental Protection Agency (EPA) estimates it would cost
between $67,700 and $70,000 per pound to achieve a 90% control level. A recent presentation
at the Air Quality conference by the United States Department of Energy (DOE) noted that the
preliminary economic analysis of field testing data indicates that good progress is being made
to reducing the indicated costs by 25 – 50%. Factors likely to influence the effectiveness and
cost-effectiveness of activated carbon include: flue gas temperature (flue gas temperature to
preferably be below 150 °C); the amount of carbon injected; particulate control equipment design; the amount, concentration, and species of mercury in the flue gas; the contact between
the carbon and mercury (efficient distribution is needed for the carbon to absorb the mercury);
the type of carbon used (e.g., activated carbon that is chemically impregnated with sulphur,
iodide, chloride or calcium hydroxide may be more effective by 25 – 45% than nonimpregnated activated carbon, particularly when most of the mercury is in elemental form)
(U.S. EPA, 2000).
22. Alternatively to carbon injection, the flue gas can be distributed throughout a carbon filter
bed. Carbon filter bed technology is assumed by U.S. EPA to remove 80 – 90% of the mercury
19
in flue gas at two large (generic) individual facilities at a cost of $33,00 to $38,000 per pound of
mercury removed.
23. Depending on the plant and coal used, periodic monitoring of Hg at frequency of at least
every third year up to continuous monitoring is recommended to confirm the effectiveness of a
chosen BAT. Continuous monitoring of Hg allows for the possibility of maximizing the capture
efficiency of a chosen BAT over short periods of time. Total Hg emissions need to be monitored in addition to the speciation of the mercury, i.e., concentration of the elemental, ionized
mercury and the Hg present as part of the particulate matter. A mass balance approach is recommended where the mercury in the coal and ash are monitored as well as the emissions from
the stack and all analyses are done by accredited laboratories.
24. The least costly retrofit options for the control of Hg emissions from units with ESP or FF
are believed to include:
The modification of dry FGD systems by the use of appropriate sorbents for the capture of
Hg and other air toxics is considered to be the easiest retrofit problem to solve.
Injection of a sorbent upstream of the ESP or FF. Cooling of the stack gas or modifications
to the ducting may be needed to keep sorbent requirements at acceptable levels;
Injection of a sorbent between the ESP and a pulse-jet FF retrofitted downstream of the
ESP. This approach will increase capital costs but reduce sorbent costs;
Installation of a semi-dry circulating fluidized-bed absorber (CFA) upstream of an existing
ESP used in conjunction with sorbent injection. It is believed that CFAs can potentially control Hg emissions at lower costs than those associated with the use of spray dryers.
25. Preliminary annual costs of Hg controls using powdered activated carbon (PAC) injection
have been estimated based on recent pilot-scale evaluations with commercially available adsorbents. These control costs range from 0.03 to 0.4 US cents/kWh, with the highest costs associated with plants having hot-side (HS) ESPs. For plants representing 89 % of current capacity and using controls other than HS- ESPs, the costs range from 0.03 to 0.2 US cents/kWh.
Assuming a 40 % reduction in sorbent costs by the use of a composite lime-PAC sorbent for
Hg removal, cost projections range from 0.02 to 0.2 US cents/kWh, with higher costs again
being associated with plants using hot-side ESPs.
Combustion of liquid fuels
26. For dedusting off-gases from new and existing liquid fuel-fired combustion plants, BAT is
the use of an ESP or a FF. Cyclones and mechanical collectors alone are not BAT, but they
can be used as a pre-cleaning stage. BAT associated emission levels for dust are lower for
combustion plants over 300 MW th because the FGD technique that is part of the BAT conclusion for desulphurisation also reduces particulate matter.
27. Liquid fuels, especially heavy fuel oil, typically contain heavy metals, in particular Vanadium and Nickel. Basically most of the heavy metals evaporate in the combustion process and
condensate later in the process on the surfaces of the particulate matter (e.g. fly ash). The ESP
is the most used technique for dedusting off-gases from heavy fuel oil firing. The FF is also an
applied technique but less important because of the elevated risk of fire, which is reduced if the
FF is applied in combination with FGD. Therefore, BAT to reduce the emissions of dust and
heavy metals are the use of high performance ESPs (reduction rate >99.5%) or, taking into
account the risk mentioned above, a FF (reduction rate >99.95%). Wet scrubbers installed primarily for mercury cost between $76,000 and $174,000 per pound of mercury removed.
20
28. According to the BREF document, periodic monitoring of heavy metals is BAT. A frequency of every year up to every third year, depending on the kind of liquid fuel used, is recommended. Total Hg especially needs to be monitored and not only the part bound to particulate matter.
Combustion of biomass and peat
29. For the pretreatment of biomass, in particular for wood, classification based on the size
and the contamination are BAT, in order to ensure stable combustion conditions, to reduce the
amount of unburned fuel in the ash, and thus to reduce peak emissions. In case the wood used
is contaminated, it is BAT to know the type of contamination of the wood and an analytical
knowledge of the contaminants for each load that arrives to the power plant.
30. For the combustion of biomass and peat, pulverised combustion, fluidised bed combustion as well as spreader stoker grate-firing technique for wood and the vibrating, water-cooled
grate for straw-firing are BAT. Pulverised peat combustion plants are not BAT for new plants.
31. For dedusting off-gases from biomass- and peat-fired new and existing combustion
plants, BAT is the use of bag-houses with FF or an ESP. When using low sulphur fuels such as
biomass, the potential for reduction performance of ESPs is reduced with low flue-gas SO2
concentrations. In this context, the FF, which leads to dust emissions around 5 mg/m³, is the
preferred technical option to reduce dust emissions. Cyclones and mechanical collectors alone
are not BAT, but they can be used as a pre-cleaning stage.
32. Biomass and peat have certain concentrations of trace elements such as heavy metals.
Basically most of the heavy metals evaporate in the combustion process and condensate later
onto the surface of the particulate matter (fly ash). Therefore, BAT to reduce the emissions of
heavy metals from flue-gases of biomass- and peat-fired combustion plants is to use a FF (reduction rate >99.95%) or a high performance ESP (reduction rate >99.5%), where the FF
should be seen as the first choice for dedusting.
Emerging techniques
33. Research so far has indicated that the most cost-effective approach to mercury control
may be an integrated multi-pollutant (SO2, NOx, PM, and mercury) control technology.
34.
35.
-
-
-
Recent data suggests that new designs of ESPs can achieve 99.8% PM reductions.
The wet scrubber efficiency for mercury removal can be increased by
Adding lime or limestone: It has been assumed that if lime or limestone is added to the
scrubber to increase the percentage of SO2 removed, the same percentage increase in the
amount of oxidized mercury removed would occur (about 18%). For units with existing
scrubbers, cost estimates range from $62,000-$258,000 per pound, with a reduction potential of 30 pounds/year.
Improving the Liquid-to-Gas Ratio. In two separate pilot studies, increasing the liquid-to-gas
ratio from 40 gallons/1000 acf (actual cubic feet) to 125 gallons/1000 acf increased the removal efficiency of oxidized mercury from 90 percent to 99 percent.
Wet FGD Tower Design. Research has shown that tray tower or open spray tower designs
can be effective in removing oxidized mercury from boiler flue gas. The tray tower design
removed from 85 to 95 percent of the total mercury (where the composition of the flue gas
21
-
was mostly oxidized mercury). The open spray tower design removed from 70 to 85 percent
of the total mercury.
Injection of activated carbon impregnated with addings increasing adsorption capacity.
Apart from sulfur, iodide, chloride or calcium compounds other impregnating agents can be
used like nobel metals, titania and selenium.
36. Low NOx technologies are also likely to reduce mercury emission in the exhaust gases
due to the lower operating temperatures. However, while some sources indicate that a reasonable reduction can be achieved, other preliminary results of staged combustion in atmospheric
fluidized bed combustion (AFBC) units indicated that low-NOx had little effect on trace element
emissions.
37. Reburning: This NOx control technology leads to an increased fly ash carbon content and
thus enhances the mercury adsorption capacity of fly ash. While increased mercury capture
has been shown to occur with increased fly ash carbon, this phenomenon has not been used in
commercial practice for the control of mercury emissions, and it should be considered a potential control option that might be available in the future.
Combustion of coal and lignite
38. Simultaneous control of SOx, NOx and mercury: This flue-gas treatment system, which is
under demonstration in the U.S., is a gas-phase oxidation process to simultaneously capture
up to 99 % of the nitrogen and sulphur oxides as well as basic vapours and heavy metals
(100 % of mercury). Capture rates of up to 99 % SOx and 98 % NOx were demonstrated at laboratory level over a wide range of temperatures found in flue-gases. Engineering cost estimates for the construction of a full scale 500 MW power plant installation is 30-50 % lower in
capital costs and with 1/6th operating costs compared to limestone/SCR. Further advantages of
the system are: no lime/limestone is used, no CO2-emissions, no catalysts are used, reagent is
recycled, proven co-product technologies, system can be retrofitted on most plants.
Combustion of liquid fuels
39. Fuel cell applications are expected to be a future technique for clean liquid fuels. At the
moment, the size of the pilot plants is small compared to large combustion plants.
Combustion of biomass and peat
40. IGCC: Pressurized gasification in an integrated gasification combined-cycle (IGCC) is one
of the high efficiency technologies which could reduce emissions from large scale power production based on solid fuels. Peat is an ideal fuel for gasification because of its high volatile
content. A demonstration plant for biomass-fired IGCC is under construction in Sweden. The
gasification of straw has only been tested successfully when done together with coal.
Co-combustion of waste and recovered fuel
41. It is expected that in future, due to the extra experience being gained with pretreatment
and abatement techniques, the degree of co-combustion will be increased above the level of
10 % on a thermal basis.
22
Emission Limit Values
42. The Protocol on Heavy Metals includes an ELV for particulate emissions for solid and
liquid fuels of 50 mg/m³ (referring to 6% O2 and 3% O2 in the flue gas, respectively). For the
heavy metals covered by the Protocol no ELV is specified.
43. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise. Application ranges normally refer to thermal energy input.
Table 4:
ELVs for the combustion of fossil fuels in utility and industrial boilers (in mg/Nm³ unless stated otherwise)
Country or
other reference
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
> 50 MW
50 solid (6% O2) and liquid (3% O2) fuels; continuous (daily) and
discontinuous measurements (hourly average)
Austria
> 50 MW
50 solid fuels (6%O2, wood 13% O2)
> 50 MW
35 liquid fuels except light fuel oil (3% O2)
> 50 MW
30 light fuel oil (3% O2)
continuous (daily) and discontinuous measurements (half-hourly
average)
Belgium
> 50 MW
> 50 MW
150 solid and liquid fuels, existing installations built before 01/07/87
(Flanders only)
50 solid and liquid fuels, all other installations
discontinuous (Flanders only, each value) or continuous measurements (daily average).
Bulgaria
< 500 MW
> 500 MW
100 solid fuels (6% O2)
50
50 liquid fuels (3% O2)
5 gaseous fuels 3%O2
Existing installations.: monthly and yearly mean, new installations.
Hourly and daily mean values.
Canada
> 25 MW el
20-25 0.095 kg/MWh net energy output (approximately 9 ng/J heat input); combustion of solid, liquid, or gaseous fuel; new installations, 6% O2
23
Czech
Republic
50 liquid fuels, existing installations
< 500 MW
> 500 MW
50-100 MW
> 100 MW
100 solid fuels, existing installations
50
50 solid and liquid fuels, new installations
30
5 gaseous fuels, new and existing installations
Finland
> 50 MW
Germany
>50 MW
Netherlands
20 all installations; solid and liquid fuels except light fuel oil; daily
average; for light fuel oil: soot level 1
20 daily average
Slovakia
Slovenia
50/30 6%/3% O2; existing installations as of 01/01/2008
50
50-500 MW
≥ 500 MW
100 For coal burning (6 % O2), existing installations
50
> 50 MW
50 liquid fuels (3% O2); existing installations
50-100 MW
50 coal burning (6 % O2) and liquid fuels (3% O2); new installations
> 100 MW
30
as of 01/01/2008
Switzerland
50 all installations if mass flow > 0.5 kg/h
17 For new utility boilers > 25 MW, the PM ELV = 6.4 ng/J (which is
equivalent to 17 mg/m 3 at 6% O2), or sources can
meet a 99.9% reduction.
35 For new industrial boilers > 3 MW, the PM ELV = 13 ng/J (which
is equivalent to 35 mg/m3 at 6% O2)
82 For existing industrial coal-fired boilers > 3 MW, the PM ELV =
30.3 ng/J (which is equivalent to 82 mg/m3 at 6% O2)
United
States of
America
BAT according to
BREF document
50-100 MW
50-100 MW
5-30 all fuels, existing installations
5-20 all fuels, new installations
100-300 MW
100-300 MW
5-25 coal and lignite and liquid fuels; existing installations
5-20 all fuels: new installations; biomass and peat: also existing instal5-20 lations
> 300 MW
> 300 MW
5-10 all fuels: existing installations; biomass and peat: also new installations
coal and lignite and liquid fuels; new installations
solid fuels: 6% O2, liquid fuels: 3% O2
ELV for Cd emissions
0.2 all installations if total load ≥ 1 g/h; common ELV for Cd, Hg, Th
and their compounds; discontinuous measurements.
Belgium
Denmark
> 5 MW
France
> 20 MW
0.05 new and existing installations (as of 01/01/2008); common ELV
for Cd, Hg, Tl: 0.1
Germany
> 50 MW
0.05 all installations; liquid fuels except light fuel oil; discontinuous
measurements; half hour average
Switzerland
0.1 hard coal; hourly average, 10% O2
0.1 all installations if mass flow > 0.5 g/h
24
United
States of
America
1.1 ELV for Total Selected Metals (i.e., 8 metals including lead and
cadmium) for existing industrial boilers is 0.001 lb/million Btu
(about 0.43 ng/J) or about 1.1 mg/m3.
ELV for Pb emissions
5 all installations if total load ≥ 25 g/h; common ELV for Sb, Pb, Cr,
Co, Cu, Mn, Pt, V, Sn and their compounds. Discontinuous
measurements.
Belgium
Denmark
> 2/5 MW
5 heavy fuel oil > 2 MW; hard coal > 5 MW; common ELV for Ni, V,
Cr, Cu, Pb; hourly average (10% O2)
France
> 20 MW
1 new and existing installations (as of 01/01/2008)
Germany
> 50 MW
Switzerland
0.5 all installations; liquid fuels except light fuel oil; discontinuous
measurements; half hour average
5 all installations if mass flow > 25 g/h
United
States of
America
1.1 ELV for Total Selected Metals (i.e., 8 metals including lead and
cadmium) for existing industrial boilers is 0.001 lb/million Btu
(about 0.43 ng/J) or about 1.1 mg/m 3.
ELV for Hg emissions
0.2 all installations if total load ≥ 1 g/h; common ELV for Cd, Hg, Th
and their compounds. Discontinuous measurements.
Belgium
Denmark
> 2/5 MW
0.1 heavy fuel oil > 2 MW; hard coal > 5 MW; hourly average (10%
O2)
France
> 20 MW
0.05 new and existing installations (as of 01/01/2008); common ELV
for Cd, Hg, Tl: 0.1
Germany
> 50 MW
0.03 all installations; solid fuels; daily average
Switzerland
United
States of
America
0.2 all installations if mass flow > 1 g/h
0.01 Mercury ELV for existing industrial boilers is 9 lb/trillion Btu (about
0.004 ng/J) heat input or about 0.01 mg/m 3.
References
EC 2001
Ambient air pollution by mercury - Position Paper. European Communities, 2001.
EIPPCB 2005
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques for Large Combustion Plants. European IPPC Bureau, Sevilla: May 2005.
Environment Canada 2003
New Source Emission Guidelines for Thermal Electricity Generation:, Canada Gazette, Part I,
January 4, 2003
25
U.S. EPA 2000
Great Lakes Binational Toxics Strategy: Draft Report for Mercury Reduction Options. United
States Environment Protection Agency, September 2000.
UNECE 2002
Control of Mercury Emissions from Coal-Fired Electric Utility Boilers. United Nations Economic
Commission for Europe, Economic and Social Council, July 2002.
UNEP (2002)
Global Mercury Assessment. United Nations Environmental Programme. UNEP Chemicals.
December 2002.
U.S. EPA, 2004
National Emission Standards for Hazardous Air Pollutants for Industrial/Commercial/Institutional Boilers and Process Heaters: Final Rule. 13 September 2004.
U.S. EPA, 2006
New Source Performance Standard (NSPS) for Utility Boilers. April 2006.
26
PRIMARY IRON AND STEEL INDUSTRY
Background
44. This category covers the processing of ferrous metal ores or concentrates with a capacity
exceeding 150 tonnes of product per day, and installations for the production of pig iron or
steel, including continuous casting, with a capacity exceeding 2.5 tonnes per hour. According
to annex III of the Protocol, BATs are considered for sinter and pellet plants, blast furnaces
(BF) and basic oxygen furnaces (BOF) with subsequent casting, that typically constitute an
integrated steel work. The secondary iron and steel industry including electric arc furnaces is
considered within the secondary iron and steel industry, while the production of mercury and
gold and other processing of non-ferrous metals is considered within the primary and secondary non-ferrous metal industry.1
45. According to Annex III, fabric filters should be used whenever possible; reducing the dust
content to less than 20 mg/m³ (hourly average). If conditions make this impossible, electrostatic
precipitators and/or high-efficiency scrubbers may be used, reducing the dust content to
50 mg/m³. Many applications of fabric filters can achieve much lower values. When using BAT
as described in annex III in the primary iron and steel industry, the total specific emission of
dust directly related to the process can be reduced to the following levels:
Sinter plants 40 - 120 g/Mg
Pellet plants 40 g/Mg
Blast furnace 35 - 50 g/Mg
BOF 35 - 70 g/Mg.
Direct reduction and direct smelting are under development and may reduce the need for sinter
plants and blast furnaces in the future.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
46. In integrated steelworks, sinter plants and steelworks dominate the overall emissions for
most atmospheric pollutants including heavy metals. Although big efforts have been made to
reduce emissions, the contribution of the sector to the total emissions to air is considerable for
a number of pollutants, especially for dust, some heavy metals and PCDD/F. The information
below is largely based on the European BREF document (EIPPCB 2001).
47. The reduction and capture of fugitive emissions is important since fallout and reentrainment (e.g., from nearby roadways and parking lots) may contribute significantly to heavy
metal loading on the surrounding area and beyond. An emission limit for a control system exhaust becomes meaningless if a significant percentage of emissions are not captured by the
control system in the first place.
1
The coverage is in accordance with the technical information given in Annex III to the Protocol, whereas the
category description as given in Annex II would cover different activities.
27
Processing of ferrous metal ores
48. Use of conventional controls to lower mercury emissions does not prevent mercury pollution permanently because it collects the mercury and transfers it to scrubber water which is
then recycled back to the beneficiation (extraction) process. However, some mercury that is
scrubbed out of the gas flows into the tailing basin, attaches to solids and settles out in the basin. There is little biological activity in the solids that settle, therefore re-volatilization of mercury
should not occur.
49. One option is to make plant area modifications to increase mercury rejection to the tailing
and reduce the recycling effect of mercury in the beneficiation process. This option calls for
modifying the ore concentrating process to increase the mercury rejection to the tailing and for
routing the scrubber water outside of the process to reduce the recycling effect of mercury in
the beneficiation process. Increases in mercury separation in the iron concentration process
will most likely come from improving the weight recovery of iron through additional stages of
grinding and flotation. Flotation as well as increased sulfide levels in the ore may also increase
the amount of mercury that is rejected to the tailing.
Sinter plants
50. For sinter plants, the following techniques or combination of techniques are considered as
BAT (according to the BREF) with regard to heavy metals and dust emissions for both new and
existing installations:
a) Waste gas de-dusting by application of:
Advanced electrostatic precipitation (ESP) (moving electrode ESP, ESP pulse system,
high voltage operation of ESP …) or
Electrostatic precipitation plus fabric filter or
Pre-dedusting (e.g. ESP or cyclones) plus high pressure wet scrubbing system.
Using these techniques, dust emission concentrations < 50 mg/Nm3 are achieved in normal operation. In case of application of a fabric filter, dust emissions of 10-20 mg/Nm3 are
achieved.
b) Minimisation of heavy metal emissions by:
Use of fine wet scrubbing systems in order to remove water-soluble heavy metal chlorides, especially lead chloride(s) with an efficiency of > 90% or a bag filter with lime addition;
Exclusion of dust from last ESP field from recycling to the sinter strand, dumping it on a
secure landfill (watertight sealing, collection and treatment of leachate), possibly after
water extraction with subsequent precipitation of heavy metals in order to minimise the
quantity to dump.
c) Recirculation of a part of the waste gas, if sinter quality and productivity are not significantly
affected.
51. Total costs of implementing fabric filtration for one representative sinter plant are 3000 to
16000 Euro p.a.
52. It is recommended that an environmental performance indicator for the sintering operation
be less than 150 grams of particulate matter per tonne of sinter produced for existing iron sinter
plants and 100 grams of particulate matter per tonne of sinter produced for modified or new
iron sinter plants [Lemmon 2004].
28
53. Best environmental practices for the minimization of emissions from the sinter strand operation include:
a) enclosure and/or hooding, where appropriate, with emission controls, of the sinter strand
operations that are potential sources of fugitive emissions;
b) operating practices that minimize fugitive emissions that are not amenable to enclosure or
hooding;
Pelletisation plants
54. For pelletisation plants, the following techniques or combination of techniques are considered as BAT (according to the BREF) with regard to heavy metals and dust emissions for
both new and existing installations:
a) Efficient removal of particulate matter from the induration strand waste gas, by means
of:
Scrubbing or
Semi-dry desulphurisation and subsequent de-dusting (e.g. gas suspension absorber
(GSA)) or any other device with the same efficiency.
Achievable removal efficiency for particulate matter: >95%; corresponding to achievable
concentration of < 10 mg dust/Nm³.
Blast furnaces
55. For blast furnaces, the following techniques or combination of techniques are considered
as BAT (according to the BREF) with regard to heavy metals and dust emissions for both new
and existing installations:
a) Hot stoves: emission concentration of dust <10 mg/Nm3 (related to an oxygen content of
3%) can be achieved
b) Blast furnace gas treatment with efficient de-dusting: Coarse particulate matter is preferably
removed by means of dry separation techniques (e.g. deflector) and should be reused.
Subsequently fine particulate matter is removed by means of:
a scrubber or
a wet electrostatic precipitator or
any other technique achieving the same removal efficiency;
A residual particulate matter concentration of < 10 mg/Nm3 is possible.
c) Cast house de-dusting (tap-holes, runners, skimmers, torpedo ladle charging points); Emissions should be minimised by covering the runners and evacuation of the mentioned emission sources and purification by means of fabric filtration or electrostatic precipitation. Dust
emission concentrations of 1-15 mg/Nm3 can be achieved. Regarding fugitive emissions 515 g dust/t pig iron can be achieved; thereby the capture efficiency of fumes is important.
d) Fume suppression using nitrogen (in specific circumstances, e.g. where the design of the
casthouse allows and nitrogen is available).
Basic oxygen steelmaking and casting
56. For oxygen steel making including hot metal pre-treatment, secondary metallurgical
treatment and continuous casting, the following techniques or combination of techniques are
considered as BAT (according to the BREF) with regard to heavy metals and dust emissions
for both new and existing installations:
a) Particulate matter abatement from hot metal pre-treatment (including hot metal transfer
processes, desulphurisation and deslagging), by means of:
Efficient capture and exhaust;
29
Subsequent purification by means of fabric filtration or ESP.
Dust emission concentrations of 5-15 mg/Nm³ are achievable with bag filters and 20-30
mg/Nm³ with ESP.
b) BOF gas recovery and primary de-dusting, applying:
Suppressed combustion and
Dry electrostatic precipitation (in new and existing situations) or
Scrubbing (in existing situations).
Collected BOF gas is cleaned and stored for subsequent use as a fuel, if economical feasible or with regard to appropriate energy management. In some cases, it may not be economical or, with regard to appropriate energy management, not feasible to recover the BOF
gas. In these cases, the BOF gas may be combusted with generation of steam. Although
the impact on reducing heavy metals is uncertain, recycling of collected dusts is a good
general practice. Special attention should be paid to the emissions of particulate matter
from the lance hole. This hole should be covered during oxygen blowing and, if necessary,
inert gas injected into the lance hole to dissipate the particulate matter.
c) Secondary de-dusting, applying:
Efficient capture and exhaust during charging and tapping with subsequent purification
by means of fabric filtration or ESP or any other technique with the same removal efficiency. Capture efficiency of about 90% can be achieved. Residual dust content of 5-15
mg/Nm³ in case of bag filters and of 20-30 mg/Nm3 in case of ESP can be achieved.
Efficient evacuation during hot metal handling (reladling operations), deslagging of hot
metal and secondary metallurgy with subsequent purification by means of fabric filtration or any other technique with the same removal efficiency. For these operations
emission factors below 5 g/t LS (liquid steel) are achievable.
Fume suppression with inert gas during reladling of hot metal from torpedo ladle (or hot
metal mixer) to charging ladle in order to minimise fume/dust generation.
-
57. It is recommended that an environmental performance indicator for TPM for the BOF
steelmaking process would be a maximum of 60 grams per tonne of molten steel for new or
modified basic oxygen furnaces and ancillary equipment and a maximum of 90 grams per
tonne of molten steel for existing basic oxygen furnaces
Emerging techniques
Sinter plants and blast furnaces
58. New ironmaking techniques discussed below may in future strongly reduce the need for
sinter plants.
59. Although the blast furnace route is the main process for iron production, several other
production routes for pig iron are currently being developed and one technique is already applied commercially (Corex). These so-called "smelting reduction" techniques invariably use coal
instead of coke as the main fuel. Some of the new techniques also replace pellets and sinter by
pulverised iron ore. Two main types of alternative ironmaking which can be considered as
proven types of alternative ironmaking are following:
a) Direct reduction (DR) involves the production of solid primary iron from iron ores and a reducing agent (e.g. natural gas). The solid product is called Direct Reduced Iron (DRI) and is
mainly applied as feedstock in electric arc furnaces (EAF) producing steel. The direct reduction process has been commercialised since the 1970's and a variety of processes have
been developed. The DR/EAF technology combination is a complete replacement of the
traditional iron sintering/coke oven/BF/BOF steelmaking route.
30
b) Smelting reduction (SR) involves combining iron ore reduction with smelting (cf. blast furnace) in a reactor, without the use of coke. The product is liquid pig iron, which can be
treated and refined in the same way as pig iron from the blast furnace. Today, only one variant of SR is commercially proven (Corex), but a number of variants are in an advanced
state of development.
These processes are alternatives to the coke oven/blast furnace route and possibly with other
direct iron smelting processes will replace blast furnaces as they become non-economic. However, no information is available with regard to emissions of heavy metals.
60. Next to the developments in ironmaking, there is a tendency towards continuous processes instead of batch processes. The shift from ingot casting to continuous casting in the
1980's is a representative example of this. In future, batch steelmaking (e.g. Linz-Donawitz converter, EAF) will probably be replaced by continuous steelmaking processes. However, no
information is available with regard to emissions of heavy metals.
Basic oxygen steelmaking and casting
61. The use of new reagents in the desulphurisation process might lead to a decrease in particulate matter emissions and a different (more useful) composition of the generated dusts. The
technique is under development.
62. Several foaming techniques at pig iron pre-treatment and steel refining are already available, absorbing the particulate matter arising from the hot metal processing.
Emission Limit Values
63. The Protocol on Heavy Metals includes an emission limit value (ELV) for particulate
emissions of 50 mg/m³ for sinter plants and for BFs, and of 25 mg/m³ for pellet plants for grinding and drying and for pelletizing or alternatively of 40 g/Mg of pellets produced. For BOF as
well as for the heavy metals covered by the Protocol no ELVs are specified.
64. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
31
Table 5:
Country or
other reference
ELVs for primary iron and steel production (in mg/Nm³ unless stated otherwise)
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
50 sinter plants
25 pellet plant: grinding, drying, pelletizing; alternatively 40 g/Mg pellets
50 blast furnaces
continuous (daily) and discontinuous measurements (hourly average)
Austria2
50 sinter plants, melting and casting of pig iron, converter, vacuum, electro
slag remelting
20 production iron and steel
continuous (daily) and discontinuous measurements (half-hour average)
gaseous or liquid fuels 3%O2 (heat furnace 5%O2), solid fuels 6% O2
Belgium
150 all installations if mass flow ≤ 500 g/h
50 all installations if mass flow > 500 g/h
discontinuous or continuous (daily average) measurements
Bulgaria
10 Blast furnaces: furnace charging
50 Sintering of metallurgic ores, blast furnaces
Czech
Republic
50 steel industry and coke-making gas; existing installations
10 blast furnace; new installations
30 production of steel used elsewhere; new installations
100 agglomerization, pelletization; existing installations
25/50 agglomerization, pelletization; new installations
100 iron production; existing installations
50 iron production; new installations
Germany
20 all installations except blast furnaces (general requirement)
10 blast furnaces (3% O2)
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
40-75 Roasting / sintering installations;
5-50 production of pig iron and steel;
8 hour average
Slovakia
Switzerland
2
50
50 all installations if mass flow > 0.5 kg/h
the regulation is currently under revision, with the aim to reach an adjustment to the state of the art
32
United
States of
America
23 Sinter plants: new installations
31 Sinter plants: existing installations
6.8 Blast Furnaces: new installations
23 Blast Furnaces: existing installations
23 to 68 Basic Oxygen Furnaces (BOFs): ELVs are in this range for various
operations at BOFs at new and existing installations.
BAT according to BREF
document
<50 sinter plant
10-20 sinter plant using fabric filter
<10 pelletisation plant
<10 blast furnaces: blast furnace gas
1-15 blast furnaces: cast house dedusting
20-30 hot metal pre-treatment (including hot metal transfer processes, desulphurisation and deslagging) using ESP
5-15 hot metal pre-treatment using bag filter
20-30 basic oxygen furnace using ESP
5-15 basic oxygen furnace using bag filter
additionally: hot metal handling (reladling operations), deslagging of hot
metal and secondary metallurgy < 5 g/t liquid steel
ELV for Cd emissions
Austria
0.2 production iron and steel; common ELV for Cd, Hg, Tl; discontinuous
measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds; discontinuous measurements.
France
Germany
0.05 basic oxygen furnace, sinter plants; if mass flow Cd+Hg+Tl > 1 g/h;
additional common ELV of 0.1 mg/Nm³
0.05 all installations (general requirement); alternatively < 0.15 g/h
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds; continuous (daily)
and discontinuous measurements (half-hour average)
Switzerland
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
Austria
5 production iron and steel; common ELV for Pb, Cr (exc. CrVI), Cu, Mn,
V, Sn; discontinuous measurements (half-hour average)
Belgium
5 all installations if mass flow ≥ 25 g/h; common ELV for Sb, Pb, Cr, Co,
Cu, Mn, Pt, V, Sn and their compounds; discontinuous measurements.
Denmark
1 all installations if mass flow > 5 g/h; hourly average
France
Germany
1 basic oxygen furnace, sinter plants; if mass flow Pb and its compounds
> 10 g/h
0.5 all installations except sinter plants (general requirement);
1 sinter plants: sintering belt
common ELV for Pb, Co, Ni, Se, Te and their compounds; continuous
(daily) and discontinuous measurements (half-hour average)
33
Switzerland
5 all installations if mass flow > 25 g/h
ELV for Hg emissions
Austria
0.2 production iron and steel; common ELV for Cd, Hg, Tl; discontinuous
measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Denmark
0.1 all installations if mass flow > 1 g/h; hourly average
France
Germany
0.05 basic oxygen furnace, sinter plants; if mass flow Cd+Hg+Tl > 1 g/h;
additional common ELV of 0.1 mg/Nm³
0.05 all installations (general requirement); alternatively < 0.25 g/h
continuous (daily) and discontinuous measurements (half-hour average)
Switzerland
0.2 all installations if mass flow > 1 g/h
References
EC 2001
Economic Evaluation of Air Quality Targets for Heavy Metals. European Commission, Entec
UK Limited, January 2001.
EIPPCB 2001
Integrated Pollution Prevention and Control: Best Available Techniques Reference Document
on the Production of Iron and Steel. European IPPC Bureau, Sevilla: December 2001.
U.S. EPA 2000
Great Lakes Binational Toxics Strategy: Draft Report for Mercury Reduction Options. United
States Environment Protection Agency, September 2000.
U.S. EPA, 2003
National Emissions Standard for Hazardous Air Pollutants (NESHAP) for Integrated Iron and
Steel Industry. United States Environment Protection Agency, May 20, 2003.
Lemmon 2004
Further Development of Emission Standards for the Iron and Steel Sector. William Lemmon
and Associates Ltd., Cheminfo Services Inc. (Report prepared for: Environment Canada).
Draft, November 2004
34
SECONDARY IRON AND STEEL INDUSTRY
Background
65. This category covers the secondary production of iron and steel (secondary fusion), including electric arc furnaces (EAF), with a capacity exceeding 2.5 tonnes per hour, for which
BATs are considered according to annex III. The production of pig-iron or steel is considered
within the primary iron and steel industry.3
66. According to the description of best available techniques (BAT) in annex III of the Protocol, the efficient collection of all emissions by installing doghouses or movable hoods or by total
building evacuation is important. For all dust-emitting processes in the secondary iron and steel
industry, dedusting in fabric filters, which reduces the dust content to less than 20 mg/m3, shall
be considered as BAT. When BAT is used also for minimizing fugitive emissions, the specific
dust emission (including fugitive emission directly related to the process) will not exceed the
range of 0.1 to 0.35 kg/Mg steel. There are many examples of clean gas dust content below 10
mg/m3 when fabric filters are used. The specific dust emission in such cases is normally below
0.1 kg/Mg.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
67. Processing of secondary raw materials such as iron and steel can be a significant source
of particulate matter and heavy metals emissions, including mercury emissions, and emission
control technologies are often applied to limit these emissions. In this case the origin of the
mercury may be from both natural impurities as well as from the intentional use of iron/steel
scrap containing mercury (e.g. switches, air-bag activators).
68. Pollution prevention techniques are very effective at reducing mercury emissions from
secondary steel production processes. For example, mercury-bearing components in steel
scrap can be removed prior to shipping the scrap to a secondary iron & steel facility. The mercury can then be recovered at a mercury recycling facility. Removal of mercury switches from
end-of-life automobiles is mandated in all European Union countries. Also, there may be opportunities to remove additional mercury-bearing components from other products prior to recycling in secondary iron & steel facilities.
69. For electric arc furnace steelmaking, the following techniques or combination of techniques are considered as BAT with regard to heavy metals and dust emissions for both new
and existing installations:
a) Dust collection efficiency:
With a combination of direct off gas extraction and hood systems or
dog-house and hood systems or
total building evacuation
3
The coverage is in accordance with the technical information given in Annex III to the Protocol, whereas the
category description as given in Annex II would cover different activities.
35
98% and more collection efficiency of primary and secondary emissions from EAF are
achievable.
b) Waste gas de-dusting by application of:
Well-designed fabric filter achieving less than 5 mg dust/Nm3 for new plants and less
than 15 mg dust/Nm3 for existing plants, both determined as daily mean values.
The minimisation of the dust content correlates with the minimisation of heavy metal emissions except for heavy metals present in the gas phase like mercury.
70. It is recommended that the following pollution prevention techniques be included as a
best environmental practice:
a) Develop and implement operating practices to prevent or minimize the contaminants in the
steel scrap or other raw materials;
b) Develop and implement operating practices to prevent or minimize the presence of mercury
in the scrap
c) Enclose the filter dust collection and discharge and carry out transfer and disposal in an
environmentally sound method.
71. It is recommended that an environmental performance indicator for the EAF steelmaking
process would be a maximum of 60 grams per tonne of molten steel for new or modified electric arc furnaces and a maximum of 120 grams per tonne of molten steel for existing electric arc
furnaces.
Emerging techniques
72. In recent years a number of new furnace types have been introduced, that might be realised at industrial scale, and that show advantages with regard to heavy metals and dust emissions:
Comelt EAF: integrated shaft scrap preheating and a complete off gas collection in each
operating phase.
Contiarc furnace: waste gas and dust volumes are considerably reduced, and the gas-tight
furnace enclosure captures all primary and nearly all secondary emissions.
Direct reduction (DR) involves the production of solid primary iron from iron ores and a reducing agent (e.g. natural gas). The solid product is called Direct Reduced Iron (DRI) and is
mainly applied as feedstock in electric arc furnaces (EAF). The direct reduction process has
been commercialised since the 1970's and a variety of processes have been developed.
The use of DRI in EAF steelmaking is forecast to continue to grow in the near future. The
major driving forces for DRI production are the need for virgin material in the EAF steelmaking process to produce higher quality steel and the increasing price of steel scrap offset by
increased natural gas prices.
The use of liquid iron might be a further option.
Emission Limit Values
73. The Protocol on Heavy Metals includes an emission limit value (ELV) for particulate
emissions of 20 mg/m³ for EAF. For other related processes and for the heavy metals covered
by the Protocol no ELVs are specified.
74. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
36
European BAT reference (BREF) document. All values are expressed in mg/Nm³ referring to
standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown
periods except stated otherwise.
Table 6:
Country
ELVs for secondary steel production (in mg/Nm³ unless stated otherwise)
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
Austria4
20 EAF > 2.5 t/h; continuous (daily) and discontinuous measurements
(hourly average)
20 EAF, induction, ladle furnace
50 converter, vacuum melting, electro slag remelting
continuous (daily) and discontinuous measurements (half-hour average), gaseous or liquid fuels 3%O2 (heat furnace 5%O2), solid fuels
6% O2
Belgium
20 EAF; discontinuous or continuous (daily average) measurements
Bulgaria
20 EAF
Czech
Republic
50 EAF < 2.5 t/h, new installations
Germany
20 EAF > 2.5 t/h, new installations
5 EAF
20 all installations (general requirement)
continuous (daily) and discontinuous measurements (half-hour average)
Slovakia
Switzerland
United
States of
America
BAT according to BREF
document
50
50 all installations if mass flow > 0.5 kg/h
12 EAF: ELV for new installations, based on regulation finalized in 1984
and applies to facilities built after 1984 (U.S. EPA, 1984).
< 15 EAF, existing installations, daily mean
< 5 EAF, new installations, daily mean
ELV for Cd emissions
Austria
0.2 production of iron and steel; common ELV for Cd, Hg, Th; discontinuous measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
France
4
0.05 EAF if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1
mg/Nm³
the regulation is currently under revision, with the aim to reach an adjustment to the state of the art
37
Germany
0.05 all installations (general requirement); alternatively < 0.15 g/h
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds; continuous (daily)
and discontinuous measurements (half-hour average)
Switzerland
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
Austria
5 production of iron and steel; common ELV for Pb, Cr (exc. CrVI), Cu,
Mn, V, Sn; discontinuous measurements (half-hour average)
Belgium
5 all installations if mass flow ≥ 25 g/h; common ELV for Sb, Pb, Cr, Co,
Cu, Mn, Pt, V, Sn and their compounds. Discontinuous measurements.
Denmark
1 all installations if mass flow > 5 g/h; hourly average
France
Germany
1 EAF if mass flow Pb and its compounds > 10 g/h
0.5 all installations (general requirement);
common ELV for Pb, Co, Ni, Se, Te and their compounds; continuous
(daily) and discontinuous measurements (half-hour average)
Switzerland
5 all installations if mass flow > 25 g/h
ELV for Hg emissions
Austria
0.2 production iron and steel; common ELV for Cd, Hg, Th; discontinuous
measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Denmark
0.1 all installations if mass flow > 1 g/h; hourly average
France
Germany
0.05 EAF if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1
mg/Nm³
0.05 all installations (general requirement); alternatively < 0.25 g/h
continuous (daily) and discontinuous measurements (half-hour average)
Switzerland
0.2 all installations if mass flow > 1 g/h
References
EIPPCB 2001
Integrated Pollution Prevention and Control: Best Available Techniques Reference Document
on the Production of Iron and Steel. European IPPC Bureau, Sevilla: December 2001.
UNEP 2002
Global Mercury Assessment. United Nations Environmental Programme. UNEP Chemicals,
December 2002.
38
U.S. EPA, 1984. New Source Performance Standard (NSPS) for Secondary Iron and Steel
(Electric Arc Furnaces). 40 Code of Federal Regulations (CFR) Part 60, Subpart AAa. October 31, 1984.
Lemmon 2004
Further Development of Emission Standards for the Iron and Steel Sector. William Lemmon
and Associates Ltd., Cheminfo Services Inc. (Report prepared for: Environment Canada).
Draft, November 2004
Lourie & Love 2002
Mercury Use in Switches in Canada and Estimating the Release of Mercury from these
Sources at Electric Arc Furnaces, prepared for CCME by Lourie & Love Inc., March 2002
39
40
IRON FOUNDRIES
Background
75. This sector covers ferrous metal foundries with a capacity exceeding 20 tonnes per day.
According to annex III of the Protocol, best available techniques (BAT) are considered for cupola and induction furnaces that are operated in iron foundries. Electric Arc Furnaces (EAFs)
are treated within the secondary iron and steel industry.
76. Rotary furnaces are not currently taken into account in Annex III but may be a relevant
source of heavy metal emissions. Therefore, additional information is given for these installations.
77. According to Annex III, the efficient collection of all emissions by installing doghouses or
movable hoods or by total building evacuation is important. Emission reduction with electrostatic precipitators (ESPs), fabric filters (FFs), the latter also combined with pre-dedusting, dry absorption or chemisorption, or venturi scrubbers can reduce dust concentrations to 20 mg/m3, or
less. For existing smaller installations, these measures may not be BAT if they are not economically viable.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
78. For the foundries industry, emissions to air are the key environmental concern. The
foundry process generates (metal-laden) mineral dusts, acidifying compounds, products of incomplete combustion and volatile organic compounds. Dust is a major issue, since it is generated in all process steps, in varying types and compositions. Dust is emitted from metal melting, sand moulding, casting and finishing. Any dust generated may contain metal and metal
oxides. In the foundry process, emissions to air will typically not be limited to one (or several)
fixed point(s). The process involves various emission sources (e.g. from hot castings, sand, hot
metal). A key issue in emission reduction is not only to treat the exhaust and off-gas flow, but
also to capture it.
79. For iron foundries, the following techniques or combination of techniques (Points 75
through 84) are considered as BAT (according to the BREF) with regard to heavy metals and
dust emissions. The BAT associated emission level for dust, after collecting and dedusting exhaust gases, for all types of furnaces (cupola, induction, and rotary furnace) and mouldings
(lost mould and permanent mould) as well as finishing operations is 5-20 mg/m³ (daily average,
standard conditions).
Fugitive emissions
80. BAT is to minimise fugitive emissions arising from various non-contained sources in the
process chain, by using a combination of the following measures. The emissions mainly involve
losses from transfer and storage operations and spills.
avoid outdoor or uncovered stockpiles, but where outdoor stockpiles are unavoidable, to
use sprays, binders, stockpile management techniques, windbreaks, etc.
cover skip and vessels
41
-
vacuum clean the moulding and casting shop in sand moulding foundries
clean wheels and roads
keep outside doors shut
carry out regular housekeeping
81. Additionally, fugitive emissions may arise from the incomplete evacuation of exhaust gas
from contained sources, e.g. emissions from furnaces during opening or tapping. BAT is to
minimise these fugitive emissions by optimising capture and cleaning. For this optimisation one
or more of the following measures are used, giving preference to the collection of fume nearest
to the source:
hooding and ducting design to capture fume arising from hot metal, furnace charging, slag
transfer and tapping
applying furnace enclosures to prevent the release of fume losses into the atmosphere
applying roofline collection, although this is very energy consuming and should only be applied as a last resort.
Cupola furnace melting of cast iron
82. The amount of dust and exhaust gases resulting are directly related to the amount of
coke charged per tonne of iron. Therefore, all measures that improve the thermal efficiency of
the cupola will also reduce the emissions from the furnace. For the operation of cupola furnaces, BAT is all of the following, to:
a) use divided blast operation (2 rows of tuyères) for cold blast cupolas
b) use oxygen enrichment of the blast air, in a continuous or intermittent way, with oxygen
levels between 22 and 25 % (i.e. 1 % - 4 % enrichment)
c) minimise the blast-off periods for hot blast cupolas by applying continuous blowing or long
campaign operation. Depending on the requirements of the moulding and casting line, duplex operations must be considered
apply good melting practice measures for the furnace operation
Operating the furnace in its optimum regime as much as possible
Avoiding excess temperatures
Uniform charging:
Minimising air losses
Avoiding “bridging” in the cupola
Utilising good lining practice
d) use coke with known properties and of a controlled quality
e) clean furnace off-gas by subsequent collection, cooling and dedusting. BAT for dedusting is
to use a bag filter or wet scrubber.
Induction furnace melting of cast iron and steel
83.
-
For the operation of induction furnaces, BAT is all of the following, to:
apply measures to increase furnace efficiency through shorter melting times and reduced
downtime.
use a hood, lip extraction or cover extraction on each induction furnace to capture the furnace off-gas and to maximise off-gas collection during the full working cycle
use dry flue-gas cleaning
keep dust emissions below 0.2 kg/tonne molten iron.
42
Rotary furnace melting of cast iron
84.
-
For the operation of rotary furnaces, BAT is all of the following, to:
use techniques to optimise furnace operation and to increase the melting efficiency.
collect the off-gas close to the furnace exit, apply post combustion, cool it using a
heatexchanger and then to apply dry dedusting.
Lost mould casting
85. For green sand moulding, BAT for green sand preparation is to enclose all the unit operations of the sand plant (vibrating screen, sand dedusting, cooling, mixing operations) and to
dedust the exhaust gas.
86. For chemically-bonded sand mould and core-making, all types of binders are determined
as BAT if they are applied according to good practice measures, which mainly involve process
control and exhaust capture measures to minimise emissions.
87. Pouring, cooling and shake-out generate emissions of dust, volatile organic compounds
(VOCs) and other organic products. BAT is to:
enclose pouring and cooling lines and to provide exhaust extraction, for serial pouring lines,
and
enclose the shake-out equipment, and to treat the exhaust gas using wet or dry dedusting.
Permanent mould casting
88. BAT for sand preparation in permanent mould casting is to enclose all the unit operations
of the sand plant (vibrating screen, sand dedusting, cooling, mixing operations) and to dedust
the exhaust gas.
89. BAT for used sand management in permanent mould foundries is to enclose the decoring unit, and to treat the exhaust gas using wet or dry dedusting.
Finishing of castings
90. For abrasive cutting, shot blasting and fettling, BAT is to collect and treat the finishing offgas using a wet or dry system. If an Argon-Oxygen Decarborization (AOD) converter is used
for steel refining, BAT is to extract and collect the exhaust gas using a roof canopy.
Emerging techniques
91. Use of low cost combustible materials in cupola melting: In order to reduce the consumption of coke, techniques have been developed to allow the use of high calorific value solid
waste (tyres, plastic pieces, etc.) together with lower grade coke as a fuel. However, the application of alternative fuels will cause a change in the flue-gas composition; leading to higher
amounts of dust for disposal, possibly with a higher content of pollutants and an increased risk
of dioxins, PAHs and heavy metals.
43
Emission Limit Values
92.
The Protocol on Heavy Metals does not specify any ELV for this category.
93. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
Table 7:
Country
ELVs for iron foundries (in mg/Nm³ unless stated otherwise)
ELV
Remarks
ELV for PM emissions
Austria
20 Induction, EAF, cupola with furnace top extraction; heat treatment; core
prod. ≥0.5 kg/h
50 other furnaces; plants of sand regeneration, mould production, cleaning
and fettling (>25 kg/h)
5% O2 for heat treatment furnaces; continuous (daily) or discontinuous
measurements (half-hour average)
Belgium
20 foundries
discontinuous or continuous (daily average) measurements
Germany
20 all installations (general requirement)
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
United
States of
America
5 daily average or half hourly average for discontinuous measurements
50 all installations if mass flow > 0.5 kg/h
4.6
13.8
2.3
11.5
Cupola or electric arc furnace: new installations
Cupola furnace: existing installations
Electric induction furnace or scrap pre-heater: new installations
Electric arc furnace, electric induction furnace or scrap pre-heater: existing installations
4.6 Pouring area or pouring station: new installations
23 Pouring area or pouring station: existing installations
BAT according to BREF
document
5-20 daily average; additionally dust emissions < 0.2 kg/tonne molten iron
for induction furnaces
ELV for Cd emissions
Austria
0.2 common ELV for Cd, Tl; 5% O2 for heat treatment furnaces; discontinuous measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
44
France
Germany
0.05 foundries; if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of
0.1 mg/Nm³
0.05 all installations (general requirement); alternatively < 0.15 g/h
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds; continuous (daily)
and discontinuous measurements (half-hour average)
Netherlands
Slovakia
Switzerland
0.05 If mass flow of Cd is > 0.25 mg/m3
50
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
Austria
5 common ELV for Pb, Zn, Cr, Cu, V, Sn; 5% O2 for heat treatment furnaces; discontinuous measurements (half-hour average)
Belgium
5 all installations if mass flow ≥ 25 g/h; common ELV for Sb, Pb, Cr, Co,
Cu, Mn, Pt, V, Sn and their compounds. Discontinuous measurements.
Denmark
1 all installations if mass flow > 5 g/h; hourly average
France
Germany
1 foundries; if mass flow Pb and its compounds > 10 g/h
0.5 all installations (general requirement);
common ELV for Pb, Co, Ni, Se, Te and their compounds; continuous
(daily) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
0.5 If mass flow of Pb is > 2.5 mg/m3
5 all installations if mass flow > 25 g/h
ELV for Hg emissions
Austria
0.1 common ELV for Hg, Be; 5% O2 for heat treatment furnaces; discontinuous measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Denmark
0.1 all installations if mass flow > 1 g/h; hourly average
France
Germany
0.05 foundries; if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of
0.1 mg/Nm³
0.05 all installations (general requirement); alternatively < 0.25 g/h
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
0.05 If mass flow of Hg is > 0.25 mg/m3
Switzerland
0.2 all installations if mass flow > 1 g/h
45
References
EIPPCB 2005
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques in the Smitheries and Foundries Industry. European IPPC Bureau, Sevilla: May 2005.
U.S. EPA, 2004. National Emission Standards for Hazardous Air Pollutants for Iron and Steel
Foundries: Final Rule, 69 Federal Register 21905. United States Environmental Protection
Agency. 22 April 2004.
46
PRIMARY AND SECONDARY NON-FERROUS METAL INDUSTRY
Background
94. This category covers the primary and secondary production of non-ferrous metals. With
respect to the heavy metals of concern, according to Annex II consideration is limited to the
production of copper, lead, zinc and mercury. For the production from ore, concentrates or
secondary raw materials of copper, lead, and zinc by metallurgical processes, the coverage is
limited to installations with a capacity exceeding 30 tonnes of metal per day for primary installations and 15 tonnes of metal per day for secondary installations. For installations for the smelting, including alloying, of these metals, including recovered products, the coverage is restricted
to installations with a melting capacity of more than 4 tonnes per day for lead and 20 tonnes
per day for copper and zinc. According to annex III, BAT are also considered for the primary
production of gold.5
95. Secondary aluminium production is not currently taken into account but may be a relevant
source of heavy metal emissions. Therefore, additional information is given for these sector.
96. Large amounts of mercury are currently brought out of use as a result of ongoing and
anticipated substitution of mercury-based chlor-alkali production in Europe and North America.
Use of mercury is declining, at both global and EU levels, yet some significant uses remain.
The main global uses are gold mining, batteries and the chlor-alkali industry, together accounting for over 75% of consumption. As a pro-active contribution to a proposed globally organised
effort to phase out primary production of mercury and to stop surpluses re-entering the market,
the European Commission intends to propose an amendment to Regulation (EC) No. 304/2003
to phase out the export of mercury from the European Community by 2011. In North America,
to reduce supply, the US Government decided in 2004 to place a large quantity of previously
stockpiled mercury into long-term storage (at least 40 years) to prevent it from entering the
market (U.S. DNSC, 2004).
97. According to annex III, BAT in this sector are the following:
a) For mercury production, soot from the condensers and settling tanks should be removed,
treated with lime and returned to the retort or furnace. For efficient recovery of mercury the
following techniques can be used:
Measures to reduce dust generation during mining and stockpiling, including minimizing
the size of stockpiles;
Indirect heating of the furnace;
Keeping the ore as dry as possible;
Bringing the gas temperature entering the condenser to only 10 to 20°C above the dew
point;
Keeping the outlet temperature as low as possible; and
Passing reaction gases through a post-condensation scrubber and/or a selenium filter.
Dust formation can be kept down by indirect heating, separate processing of fine grain
classes of ore, and control of ore water content. Dust should be removed from the hot reaction gas before it enters the mercury condensation unit with cyclones and/or ESPs.
5
The coverage is in accordance with the technical information given in Annex III to the Protocol, whereas the
category description as given in Annex II would cover different activities.
47
b) For gold production by amalgamation, similar strategies as for mercury can be applied.
Gold is also produced using techniques other than amalgamation, and these are considered to be the preferred option for new plants.
c) For the production of non-ferrous metals from sulfitic ores, fabric filters should be used
when appropriate. A dust content of less than 10 mg/m3 can be obtained. The dust should
be recycled in-plant or off-site. Before being fed to an SO3 contact plant, the off-gas must
go through a thorough dedusting (< 3 mg/m3) and could also require additional mercury
removal thereby also minimizing heavy metal emissions.
d) For primary lead production, first experiences indicate that there are interesting new direct
smelting reduction technologies without sintering of the concentrates. These processes are
examples of a new generation of direct autogenous lead smelting technologies which pollute less and consume less energy.
e) Secondary lead is mainly produced from used car and truck batteries,. This BAT should
include one melting operation in a short rotary furnace or shaft furnace. Oxy-fuel burners
can reduce waste gas volume and flue dust production by 60%. Cleaning the flue-gas with
fabric filters makes it possible to achieve dust concentration levels of 5 mg/m3.
f) For primary zinc production, pressure leaching may be an alternative to roasting and may
be considered as a BAT for new plants depending on the concentrate characteristics.
Emissions from pyrometallurgical zinc production in Imperial Smelting (IS) furnaces can be
minimized by using a double bell furnace top and cleaning with highefficiency scrubbers, efficient evacuation and cleaning of gases from slag and lead casting, and thorough cleaning
(< 10 mg/m3) of the CO-rich furnace off-gases.
g) In general, processes should be combined with an effective dust collecting device for both
primary gases and fugitive emissions. Dust concentrations below 5 mg/m3 have been
achieved in some cases using fabric filters.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
98. The main environmental issues for the production of most non-ferrous metals from primary raw materials include the potential emission to air of dust and metals/metal compounds. The
pyrometallurgical processes are potential sources of dust and metals from furnaces, reactors
and the transfer of molten metal. The production from secondary raw materials is also related
to the off-gases from the various furnaces and transfers that contain dust and metals.
99. In the majority of cases these process gases are cleaned in fabric filters and so the emissions of dust and metal compounds such as lead are reduced. Gas cleaning using wet scrubbers and wet electrostatic precipitators is particularly effective for process gases that undergo
sulfur recovery in a sulfuric acid plant. In some cases where dust is abrasive or difficult to filter,
wet scrubbers are also effective. The use of furnace sealing and enclosed transfers and storage is important in preventing fugitive emissions.
Materials handling and storage
100. The techniques that are used depend to a large extent on the type of material that is being used. BAT to prevent releases of particulate matter and heavy metals from raw material
handling are:
Transfer conveyors and pipelines placed in safe, open areas above ground so that leaks
can be detected quickly and damage from vehicles and other equipment can be prevented.
Where required, sealed delivery, storage and reclamation systems can be used for dusty
materials and silos can be used for day storage. Completely closed buildings can be used
for the storage of dusty materials and may not require special filter devices.
48
-
-
Sealing agents (such as molasses and PVA) can be used where appropriate and compatible to reduce the tendency for material to form dust.
Where required enclosed conveyors with well designed, robust extraction and filtration
equipment can be used on delivery points, silos, pneumatic transfer systems and conveyor
transfer points to prevent the emission of dust.
Rationalised transport systems can be used to minimise the generation and transport of
dust within a site.
Fume and gas collection
101. Emissions to air arise from the storage, handling, pre-treatment, pyro-metallurgical and
hydrometallurgical stages. Transfer of materials is particularly important. Data provided has
confirmed that the significance of fugitive emissions in many processes is very high and that
fugitive emissions can be much greater than those that are captured and abated. In these cases it is possible to reduce environmental impact by following the hierarchy of gas collection
techniques from material storage and handling, reactors or furnaces and from material transfer
points. Potential fugitive emissions must be considered at all stages of process design and development. The hierarchy of gas collection from all of the process stages is:
Process optimisation and minimisation of emissions;
Sealed reactors and furnaces;
Targeted fume collection;
102. With regard to dust and heavy metals emissions, important gas collection measures are:
The use of sealed furnaces or other process units to prevent fugitive emissions, allow heat
recovery and the collection of process gases.
The use of semi-sealed furnaces where sealed furnaces are not available.
The minimisation of material transfers between processes.
Where such transfers are unavoidable, the use of launders in preference to ladles for molten materials.
In some cases the restriction of techniques to those that avoid molten material transfers
may prevent the recovery of some secondary materials that would then enter the waste
stream. In these cases the use of secondary or tertiary fume collection is appropriate so
that these materials can be recovered.
Hooding and ductwork design to capture fume arising from hot metal, matte or slag transfers and tapping.
Furnace or reactor enclosures may be required to prevent release of fume losses into the
atmosphere.
Where primary extraction and enclosure are likely to be ineffective, then the furnace can be
fully closed and ventilation air drawn off by extraction fans to a suitable treatment and discharge system.
Roofline collection of fume is very energy consuming and should be a last resort.
Removal of mercury
103. Mercury removal is necessary when using raw materials that contain the metal. Mercury
appears as an impurity of copper, zinc, lead, and nickel ores. The element is also present in
the gold ores. The following techniques are considered to be BAT.
The Boliden/Norzink process with the recovery of the scrubbing solution and production of
mercury metal.
Bolchem process with the filtering off the mercury sulphide to allow the acid to be returned
to the absorption stage.
Outokumpu process: Mercury is removed as sulphide from the gas stream.
49
-
Sodium thiocyanate process.
Activated Carbon Filter. An adsorption filter using activated carbon is used to remove mercury vapour from the gas stream as well as dioxins.
104. For processes where mercury removal from the gases is not practicable the two processes to reduce the mercury content in sulphuric acid produced during the production of nonferrous metals are considered to be BAT.
Superlig Ion Exchange process.
Potassium iodide process.
The emissions associated with the above processes are related to any residual mercury that
will be present in the acid that is produced, the product specification is normally < 0.1 ppm
(mg/l) and is equivalent to ~ 0.02 mg/Nm3 in the cleaned gas.
105. Formation of particles of chloride and sulfate salts was considered to be an important
removal mechanism for mercury in the FGD process. This would be promoted by high Cl content in the coal and for mercury sulfate, and by low temperatures combined with the catalytic
effect of activated carbon.
The relatively low temperatures found in wet scrubber systems allow many of the more volatile trace elements to condense from the vapor phase and thus to be removed from the
flue gases. In general, removal efficiency for mercury ranges from 30 to 50%.
In summary, the overall removal of mercury in various spray dry systems varies from about
35 to 85%. The highest removal efficiencies are achieved from spray dry systems fitted with
downstream fabric filters.
106. Mercury releases and health hazards from artisanal gold mining activities may be reduced by educating the miners and their families about hazards, by promoting certain techniques that are safer and that use less or no mercury and, where feasible, by putting in place
facilities where the miners can take concentrated ores for the final refining process.
Abatement of dust and heavy metals emissions
107. BAT for the abatement of dust and heavy metals emissions are the following:
Fume collection systems used should exploit furnace or reactor sealing systems and be
designed to maintain a reduced pressure that avoids leaks and fugitive emissions, where
applicable. Systems that maintain furnace sealing or hood deployment should be used. Examples are through electrode additions of material, additions via tuyeres or lances and the
use of robust rotary valves on feed systems. The use of an intelligent system capable of
targeting the fume extraction to the source and duration of any fume is more energy efficient.
Overall for dust and associated metal removal, fabric filters (after heat recovery or gas cooling) can provide the best performance provided that modern wear resistant fabrics are
used, the particles are suitable and continuous monitoring is used to detect failure. Modern
filter (e.g. membrane filter) offer significant improvements in performance, reliability and life
and therefore offer cost savings in the medium term. They can be used in existing installations and can be fitted during maintenance. They feature bag burst detection systems and
on-line cleaning methods.
For sticky or abrasive dusts, wet electrostatic precipitators or scrubbers can be effective
provided that they are properly designed for the application.
Best Available Techniques for gas and fume treatment systems are those that use cooling
and heat recovery if practical before a fabric filter except when carried out as part of the
production of sulphuric acid. The gas cleaning stage that is used prior to the sulphuric acid
plant will contain a combination of dry ESP, wet scrubbers, mercury removal and wet ESP.
50
BAT for gas collection and abatement for the various process stages regarding to PM and
heavy metals are summarized in the following table:
Materials handling and storage.
Grinding, drying.
Sintering/roasting, Smelting,
Converting, Fire refining
Slag treatment.
Thermal refining.
Electrode baking, graphitisation
Metal powder production
Melting and casting.
Correct storage, handling and transfer. Dust collection and fabric
filter if necessary.
Process operation. Gas collection and fabric filter.
Gas collection, gas cleaning in fabric filter, heat recovery.
Gas collection, cooling and fabric filter.
Gas collection and fabric filter.
Gas collection, condenser and ESP, afterburner or alumina scrubber and fabric filter.
Gas collection and fabric filter.
Gas collection and fabric filter.
108. FFs may not be BAT for the recovery of non-ferrous metals from sulfur-bearing concentrates due to the potential for condensation of sulphuric acid on the baghouse filter media particularly during temporary outages and operation at gas temperatures below the acid gas dew
point. If FFs are correctly designed, constructed and sized, they can be considered as BAT.
The ESP may be the preferred PM abatement method for some applications. It will tolerate
short periods of condensation without plugging/blinding as occurs immediately even with modern fabric filters (e.g., membrane filter bags).
109. When BAT are used, the associated emission level for dust, depending on its characteristics, for FF and alumina scrubber is 1-5 mg/Nm³, and for wet ESP or ceramic filter < 5
mg/Nm³ (daily average, standard conditions).
110. The concentration of heavy metals is linked to the concentration of dust and proportion of
the metals in the dust. The metal content of dust varies widely between processes. In addition,
for similar furnaces there are significant variations in metal content due to the use of varying
raw materials. It is considered that low concentrations of heavy metals are associated with the
use of high performance, modern abatement systems such as a membrane fabric filter provided the operating temperature is correct and the characteristics of the gas and dust are taken
into account in the design. A total dust retention of more than 99.75 % can be achieved with
the use of ESPs and FFs, the contents of heavy metals, including mercury on particles in the
flue gas can be reduced by at least 95.0 to 99.0 %.
Production of copper and its alloys from primary and secondary raw materials
111. Process selection for primary copper smelting: Depending on the raw materials available,
BAT are:
The continuous processes from Mitsubishi and Outokumpu/Kennecott are considered to be
BAT for the smelting and converting stage. The Mitsubishi system also treats copper secondary raw material and scrap. The Mitsubishi and Outokumpu processes are derivatives
of the Canadian INCO flash furnace which was the first continuous smelting process for
copper and nickel. The Mitsubishi and Outokumpu processes are derivatives of the Canadian INCO flash furnace which was the first continuous smelting process for copper and
nickel.
Similar environmental performance, using concentrate blends from various sources, can be
achieved using the Outokumpu Flash Smelting Furnace, and for smaller throughputs the
51
ISA Smelt furnace. These furnaces are used in combination with the Peirce-Smith (or similar) converter.
The combination of partial roasting in a fluid bed roaster, electric furnace matte smelting
and Peirce-Smith converter offers advantages for the treatment of complex feed materials
allowing recovery of other metals contained in the concentrate like zinc and lead.
The use of the Outokumpu Flash Smelting Furnace for direct smelting to blister copper using specific concentrates with a low iron content or very high grade concentrates (low slag
fall).
The Noranda, El Teniente converter and Contop furnaces may also achieve the same environmental performance as those listed above, given good gas collection and abatement
systems. The INCO flash furnace may also have advantages but operates with 100% oxygen resulting in a narrow operating window.
Gases from the primary smelting and converting processes should be treated to remove dust
and volatile metals.
112. Process selection for the production of copper from secondary raw materials: For the
production of copper from secondary raw materials the variation in feed stock and the control of
quality also has to be taken into account at a local level and this will influence the combination
of furnaces, pre-treatment and the associated collection and abatement systems that are used.
BAT are Blast Furnaces, mini-smelter, TBRC, Sealed Submerged Arc Electric furnace, ISA
Smelt, and the Peirce-Smith converter. The submerged arc electric furnace is a sealed unit and
is therefore inherently cleaner than the others, provided that the gas extraction system is adequately designed and sized. The electric furnace is also used for secondary material. For high
grades of copper scrap without organic contamination, the reverberatory hearth furnace, the
hearth shaft furnace and Contimelt process are considered to be BAT in conjunction with suitable gas collection and abatement systems.
113. Process selection for primary and secondary converting: If batch operated converters
such as the Peirce-Smith converters (or similar) are used they should be used with total enclosure or efficient primary and secondary fume collection systems. The hooding systems should
be designed to allow access for the ladle transfers while maintaining good fume collection. This
can be achieved by the use of a system of intelligent control to target fume emissions automatically as they occur during the cycle. The blowing cycle of the converter and the fume collection
system should be controlled automatically to prevent blowing while the converter is rolled out.
Additions of materials through the hood or tuyeres should be used if possible. The ISA Smelt
furnace can be operated batch-wise, where smelting is carried out in a first stage followed by
conversion in a second stage, and is also considered as BAT.
114. Process selection for other processes stages: BAT are:
The drying of concentrate etc in directly fired drum and flash dryers, in fluid bed and steam
dryers.
Slag treatment by electric furnace slag cleaning, slag fuming, crushing/grinding and slag
flotation.
Fire refining in rotary or tilting reverberatory furnaces. Anode casting in pre-formed moulds
or in a continuous caster.
Electrolytic copper refining by optimised conventional or mechanised permanent cathode
technology.
The hydro-metallurgical processes using the electro-winning process are considered to be
BAT for oxidic ores and low grade, complex and precious metal free copper sulphide ores.
52
115. Gas collection and abatement: Fume production from secondary raw materials can be
minimised by the choice of the furnace and abatement systems. Secondary fume collection is
needed in the case of some batch converters and for the ventilation of tap-holes, launders etc.
BAT for gas collection and abatement for the various process stages with the regard to PM and
HM are summarized in the following table:
Raw materials handling.
Correct storage, handling and transfer. Dust collection and fabric
filter.
Raw materials thermal pretreatment
Correct pre-treatment. Gas collection and fabric filter.
Primary smelting
Process operation and gas collection, gas cleaning followed by gas
cooling/final cleaning (normally followed by sulphuric acid plant)
Secondary smelting
Process operation and gas collection, cooling and cleaning by fabric filter; scrubbing if necessary
Primary converting
Process operation and gas collection, gas cleaning (followed by
sulphuric acid plant)
Secondary converting
Process operation and gas collection, cooling and cleaning by fabric filter; scrubbing if necessary
Fire refining
Process operation and gas collection, cooling and cleaning by fabric filter or scrubber
Melting and casting.
Process operation and gas collection, cooling and cleaning by fabric filter.
Pyro-metallurgical slag treatment
Process operation and gas collection, cooling and cleaning by fabric filter.
116. The BAT associated emission level for dust is 1-5 mg/Nm³ (daily average). For secondary
smelting and converting, primary and secondary fire refining, electric slag cleaning and melting,
it can be reached using high performance fabric filters. For secondary fume collection systems
and drying processes, fabric filter with lime injection (for SO2 collection/filter protection) are
BAT.
Production of aluminium from secondary raw materials
117. Process selection for secondary aluminium smelting: The smelting and melting processes
that are considered to be BAT are the Reverberatory furnace, Tilting rotary furnace, Rotary
furnace, Meltower Induction furnace, depending on the feed materials, with the following features:
The use of a sealed charging carriage or similar sealed feeding system if possible.
The use of enclosures or hoods for the feeding and tapping areas and targeted fume extraction systems if practical
The use of coreless-induction furnaces for relatively small quantities of clean metal
The use of fabric or ceramic filters for dust removal.
118. Process selection for other processes stages: BAT for Holding or De-gassing is the fume
collection from furnaces and launders, cooling, and fabric filter if necessary.
53
119. Gas collection and abatement: BAT for gas and fume treatment systems are those that
use cooling and heat recovery if practical before a fabric filter. FF or ceramic filters that use
modern high performance materials in a well constructed and maintained structure are applicable. The use of or the recycling of skimmings and filter dusts, if it is possible, is considered to
be part of the processes. BAT for gas collection and abatement for the various process stages
are summarized in the following table:
Raw materials handling.
Dust prevention and correct storage. Dust collection and fabric
filter.
Raw materials pre-treatment
Correct pre-treatment. Gas collection and fabric filter.
Secondary smelting
Process operation, gas collection and efficient dust removal.
Holding and refining
Process operation and gas collection/cleaning
Salt slag and skimmings
treatment processes
Process operation and gas collection/treatment
120. The BAT associated emission level for dust is 1-5 mg/Nm³ (daily average) for materials
pre-treatment (including swarf drying), melting and smelting of secondary aluminium and holding and de-gassing molten metal, using a high performance fabric filter.
Production of lead and zinc from primary and secondary raw materials
121. Process selection for primary lead smelting: Depending on the raw materials available,
BAT are:
applied technique
raw material
Kaldo process TBRC (Totally
enclosed)
Pb concentrate and secondary (most grades)
ISF and New Jersey Distillation
Zn/Pb concentrates
QSL
Pb concentrate and secondary material
Kivcet furnace
Cu/Pb concentrate and secondary material
Kaldo Furnace
Pb concentrate and secondary material
ISA Smelt Furnace
Pb concentrate and secondary material
Blast Furnace
complex lead bearing primary and secondary material
Gases from the sintering, roasting and direct smelting processes should be treated to remove
dust and volatile metals.
122. Process selection for secondary lead smelting: Depending on the raw materials available,
processes that are BAT are: The blast furnace (with good process control), ISA Smelt/Ausmelt,
the electric furnace and the rotary furnace. The submerged arc electric furnace is used for
mixed copper and lead materials. It is a sealed unit and is therefore inherently cleaner than the
others, provided that the gas extraction system is adequately designed and sized. The electric
furnace is used for secondary material containing sulphur and is connected to a sulphuric acid
plant. When only clean lead and clean scrap is used, also melting crucibles and kettles is BAT.
54
123. Process selection for lead refining: Processes would be used with efficient primary and if
necessary, secondary fume collection systems. Temperature control of the refining kettles is
articularly important to prevent lead fume and indirect heating is more effective in achieving
this.
124. Process selection for primary and secondary zinc production: No specific process is BAT
provided that for any process good process control, gas collection and abatement systems are
used.
125. Gas collection and abatement: The ISF process need to use wet scrubbing so that the
gases are cooled prior to use as a fuel. BAT for gas collection and abatement for the various
process stages are summarized in the following table:
Raw materials handling.
Correct storage, dust collection and fabric filter.
Raw materials pre-treatment
(mechanical decoating/stripping; thermal decoating)
Correct pre-treatment. Gas collection and fabric filter.
Primary roasting and smelting, Process operation, gas collection, gas cleaning, cooling and sulsintering
phuric acid plant
ISF
Wet scrubbing (to cool gas) prior to use as LCV (low calorific value)
gas
Secondary smelting
Process operation and gas collection, cooling and fabric filter
Thermal refining
Process operation, gas collection, cooling and fabric filter
Melting, alloying, casting and
dust production
Process operation, gas collection, cooling and fabric filter
Slag fuming and Waelz kiln
processes
Process operation, gas collection, cooling and fabric filter or wet
ESP if wet quenching is used.
126. The BAT associated emission level for dust is 1-5 mg/Nm³ (daily average). This can be
achieved using a high performance fabric filter for the melting of clean material, alloying and
zinc dust production. Temperature control of melting kettles or vessels is needed to prevent
volatilisation of metals. For materials pre-treatment, secondary smelting, thermal refining, melting, slag fuming and Waelz kiln operation, this can be achieved using a high performance fabric filter or wet ESP (A wet ESP may be applicable to gases from slag granulation or wet gas
quenching).
Production of gold
127. Process selection: No specific process is considered as BAT. The use of the copper route
for smelting precious metals has a lower potential for the emission of lead to all environmental
media and should be used if the combination of raw materials, equipment and products allows
it.
128. In Nevada, USA, as part of the Voluntary Mercury Reduction Program several large gold
production facilities reduced their mercury emissions within two to three years (2000-2003) by
about 75% by applying various control technologies and pollution prevention measures, includ-
55
ing carbon adsorption units, mercurous chloride scrubbers, venture scrubbers, and chemical
additives to improve mercury capture (Miller and Jones 2005).
129. Gas collection and abatement: Secondary fume collection is needed in the case of some
furnaces. The use of or the recycling of acids, slags, slimes and filter dusts are considered to
part of the processes. In the case of high content of mercury in the ore it is necessary to use an
activated carbon adsorber bed. BAT for gas collection and abatement for the various process
stages are summarized in the following table:
Raw materials handling.
Correct storage. Dust collection and fabric filter if necessary.
Raw materials pre-treatment
Correct pre-treatment. Gas collection and fabric filter.
Roasting and smelting
Process operation, gas collection, cooling and fabric filter; scrubbing if necessary
Selenium roasting
Process operation, gas collection, cooling and dust removal,
scrubbing and wet ESP
Dissolution and chemical refin- Process operation and gas collection with oxidising scrubber
ing
Thermal refining (Miller process)
Process operation, gas collection, scrubbing and wet ESP
Melting, alloying and casting
Process operation, gas collection, cooling and fabric filter
Slag treatment and cupelling
Process operation, gas collection, cooling and fabric filter.
130. The BAT associated emission level for dust for materials pre-treatment (including incineration), roasting, cupelling, smelting, thermal refining, and melting for precious metal recovery
is 1-5 mg/Nm³ (daily average). This can be achieved using a high performance fabric filter or
ceramic filter.
Production of mercury
131. Materials handling and storage In addition to the generic BAT for materials handling and
storage, because of the vapour pressure of mercury, storage of the product in sealed and isolated flasks is considered to be BAT.
132. Process selection for mercury production: The Best Available Technology to produce
mercury is the production of mercury from secondary raw materials. Only in situations were
waste mercury cannot be obtained, for primary mercury production from cinnabar using the
Herreschoff furnace is BAT. For other production either from gas treatment systems for other
non-ferrous metals or from secondary raw materials it is not possible to conclude that a single
production process is BAT.
133. Gas collection and abatement: Best Available Techniques for gas and fume treatment
systems are those described for mercury removal. For dust forming process stages a fabric
filter is considered to be BAT. BAT for gas collection and abatement for the various process
stages are summarized in the following table:
56
Ore grinding and conveying.
Dust collection and fabric filter.
Handling secondary material
Enclosed handling, scrubbing of ventilation gases
Primary or secondary roasting
Mercury condenser and mercury scrubber system.
Product handling
Enclosed filling station, scrubbing of ventilation gases.
The performance of the scrubber based processes are uncertain for fine mercury particles and
it is concluded that further investigation of the techniques in this application is needed before
BAT can be confirmed and associated emissions given.
134. The BAT associated emission level for dust from ore grinding, roasting, distillation and
associated processes for primary production of mercury is 1-5 mg/Nm³ (daily average). This
can be achieved using a fabric filter, while a wet ESP may be applicable to gases from slag
granulation. Mercury emissions to air from secondary production and production from base
metals associated with the use of BAT in the mercury sector are of 0.02 mg/Nm³ (daily average), what can be achieved by a mercury scrubber (Boliden, thiosulphate etc).
Emerging techniques
135. The application of selenium filter is proposed as a dry media process, which can be applied at both steel and non-ferrous metal smelters. Mercury removal of above 90 % has been
achieved through this technique reducing the mercury concentrations to below 0.01 mg/m³.
Selenium filters are recommended for the removal of mercury from the flue gas stream upstream of the acid plant in non-ferrous metal smelters. For copper production, the estimates of
the annualized cost indicate a range from 1990 US$ 10.0 to more than 50.0 per tonne of copper. In the case of lead smelters this cost is about 50 % lower.
136. The mercury reduction of a selenium scrubber is about 90–95%, resulting in mercury
concentrations of about 0.2 mg/m³. However, at low incoming Hg concentrations the removal
efficiency can be less than 90 %.
137. For the Odda chloride process, mercury concentrations of the treated gases are 0.05-0.1
mg/m³.
Production of copper and its alloys from primary and secondary raw materials
138. Bath smelting can offer low cost installations because of the potential high reaction rates
in modern plant coupled with sealed or semi-sealed furnaces. Plant reliability needs to be
proven in the long term.
139. ISA Smelt for reduction/oxidation is not industrially proven but is emerging.
140. The use of hydro-metallurgical processes is also emerging and they are suitable for
mixed oxidic/sulphidic ores that contain low concentrations of precious metals. Some processes are being developed for concentrates and dust treatment based on leaching for example
leach-solvent extraction-electro-win (L:SX:EW) processes.
57
141. Developments in other industrial sectors may also be seen as emerging for copper production processes. Particular developments are:
(a) The use of modern fabrics for bag filters mean that more effective and robust fabrics (and
housing design) can allow bag life to extended significantly, improving performance and reducing costs at the same time.
(b) The use of intelligent damper controls can improve fume capture and reduce fan sizes and
hence costs. Sealed charging cars or skips are used with a reverberatory furnace at a secondary aluminium smelter and reduces fugitive emissions to air significantly by containing emissions during charging.
Production of aluminium from secondary raw materials
142. Reuse of filter dust from secondary aluminium production: Dust and fume from a rotary
furnace is treated with sodium bicarbonate and activated carbon as the scrubbing medium to
remove chlorides produced by the salt flux and sodium chloride is formed. The dust is then
collected in a fabric filter and can be included with the salt charged to the furnace.
143. Catalytic filter bags.
Production of lead and zinc from primary and secondary raw materials
144. Leaching processes based on chloride for zinc and lead recovery are reported as being at
the demonstration stage.
145. The injection of fine material via the tuyeres of a blast furnace has been successfully
used and reduces the handling of dusty material and the energy involved in returning the fines
to a sinter plant.
146. Control parameters such as temperature are used for melting furnaces and kettles and
reduce the amount of zinc and lead that can be fumed from a process.
147. Furnace control systems from other sectors may be available for the blast furnace and
ISF.
148. The EZINEX process is based ammonia/ammonium chloride leaching followed by cementation and electrolysis. It was developed for the direct treatment of EAF dusts and one plant is
operational. It may be used for richer secondary zinc feed.
149. The Outokumpu Flash Smelting Furnace has been used on a demonstration basis for the
production of lead by direct smelting. The use of Waelz kilns for this purpose has also been
reported. The literature contains many other potential examples that have not yet been developed beyond the pilot scale.
150. For the lead sulfide process, a mercury removal efficiency of 99.0 % has been measured,
resulting in mercury emission concentrations of 0.01-0.05 mg/Nm³.
151. The BSN process treats pelletised EAF dust by drying and clinkering followed by the reduction, volatisation and re-oxidation to produce ZnO.
58
Production of gold
152. The 'J' process is not operated in Europe but can operate with a lower inventory of gold
compared with other gold refining processes. It uses a re-generable iodine solution to dissolve
impure gold (< 99.5%). The gold is reduced by potassium hydroxide, separated, washed and
dried to a powder containing 99.995% gold. Liquor from the reduction stage is fed to an electrolytic cell where soluble impurities and any unreduced gold iodide are deposited on the cathode
and removed for recovery in a precious metals circuit. The solution is then transferred to an
electrolytic diaphragm cell fitted with inert electrodes. Iodine solution produced in the anode
compartment and KOH solution produced in the cathode compartment are recycled
153. A process has been designed to treat a pyrite concentrate that contains microscopic gold
particles (< 1 µm) to produce a gold dore, a lead/silver concentrate and a zinc concentrate
Production of mercury
154. A process integrated with primary mercury production is being developed to recover mercury that is removed from processes that are substituting other materials for mercury. This development will include the abatement of fine mercury particles and this technique will be available for primary mercury production.
Overview on ELVs and BAT associated emission levels
155. The Protocol on Heavy Metals includes an ELV for particulate emissions for the production of copper and zinc, including Imperial Smelting furnaces, of 20 mg/m³, and of 10 mg/m³ for
the production of lead. No ELV is specified for the heavy metals covered by the Protocol, nor
for the production of mercury or gold.
156. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
59
Table 8:
ELVs for primary and secondary production of non-ferrous metal industry (in mg/Nm³ unless
stated otherwise)
Country
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
20 production of copper and zinc, including Imperial Smelting furnaces
10 production of lead
continuous (daily) and discontinuous measurements (hourly average)
Austria6
20 > 5 MW (electric furnace > 3MW);
10 production of Pb and Zn, > 1MW
6% O2 solid, 3% O2 liquid and gaseous fuels; continuous (daily) and
discontinuous measurements (half-hour average)
Belgium
10 primary lead production and melting
20 primary production and melting of other non-ferrous metals
continuous measurements, daily average.
Bulgaria
20 production of copper and zinc
10 production of lead
Canada
23 Secondary Lead Smelters : operations involving the use of holding
furnaces, kettle furnaces or lead oxide production units or involving
scrap handling and material handling, crushing, furnace tapping, furnace slagging, furnace cleaning or casting
46 Secondary Lead smelters : operations involving the use of blast furnaces, cupolas or reverberatory furnaces
50 Quebec regulation for zinc smelting plants
50 Emission guideline for release concentration of total particulate matter
from process air emissions at base metals smelters and refineries
Germany
5 production of non-ferrous unrefined metals, roasting, smelting or sintering
of non-ferrous metal ores
5 melting, alloying or refining of non-ferrous metals (non-ferrous metal
foundries with a production capacity of > 20 t/d or > 4 t/d for lead and cadmium)
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
United
States of
America
6
1-5 prod. of copper, lead, zinc, gold and mercury; daily average
50 all installations if mass flow > 0.5 kg/h
Primary Copper Smelting: Nonsulfuric acid PM limit of 6.2 mg/dscm for
flash smelting furnaces, slag cleaning vessels and batch converters
The regulation is currently under revision, with the aim to reach an adjustment to the state of the art
60
BAT according to BREF
document
1-5 prod. of copper, lead, zinc, gold and mercury; daily average
ELV for Cd emissions
UNECE
Austria
Belgium
continuous (daily) and discontinuous measurements (hourly average)
0.05 additionally common ELV for Cd, Hg, Be, Tl < 0.2 mg/m³; discontinuous
measurements (half-hour average)
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Canada
Base metals smelters and refineries are to develop facility emission
reduction targets for, and timetables to achieve, reductions in releases
taking into account facility emission reduction targets for sulphur dioxide and particulate matter, pollution prevention and control options, and
performances for various feeds, smelting processes, and emission
control systems
France
0.05 primary and secondary production of lead, zinc and aluminium; if mass
flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1 mg/Nm³
Germany
0.05 all installations (general requirement); alternatively < 0.15 g/h
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds; continuous (daily)
and discontinuous measurements (half-hour average)
Netherlands
Switzerland
0.05 If mass flow of Cd is > 0.25 mg/m3
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
UNECE
continuous (daily) and discontinuous measurements (hourly average)
Austria7
5 Common ELV for Pb, Zn, Cr (except for Cr-VI), Cu, Mn, V, Sn; discontinuous measurements (half-hour average)
Belgium
5 all installations if mass flow ≥ 25 g/h; common ELV for Sb, Pb, Cr, Co,
Cu, Mn, Pt, V, Sn and their compounds. Discontinuous measurements.
Canada
Base metals smelters and refineries are to develop facility emission
reduction targets for, and timetables to achieve, reductions in releases
taking into account facility emission reduction targets for sulphur dioxide and particulate matter, pollution prevention and control options, and
performances for various feeds, smelting processes, and emission
control systems
Denmark
France
7
1 all installations if mass flow > 5 g/h; hourly average
1 primary and secondary production of lead, zinc and aluminium; if mass
flow Pb and its compounds > 10 g/h
The regulation is currently under revision, with the aim to reach an adjustment to the state of the art
61
Germany
0.5 all installations (general requirement);
1 sinter plant: sintering belt
1 prod. of non-ferrous unrefined metals except lead
2 production of lead
1 lead refining
common ELV for Pb, Co, Ni, Se, Te and their compounds; continuous
(daily) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
0.5 If mass flow of Pb is > 2.5 mg/m3
1 Production of lead battery
5 all installations if mass flow > 25 g/h
United
States of
America
Primary Lead Smelting: 500 grams of lead per megagram of lead metal
produced
Secondary Lead Smelting: Lead limit of 2.0 mg/dscm for all furnace
types (blast, reverberatory, rotary and electric).
ELV for Hg emissions
Protocol
(Annex V)
continuous (daily) and discontinuous measurements (hourly average)
Austria
0.1 Sum Be and Hg, additionally common ELV for Cd, Hg, Be, Tl < 0.2
mg/m³; discontinuous measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Canada
existing primary zinc, lead and copper smelters: 2 g Hg/tonne total production of finished metals (as of 2008)
new and expanding primary zinc, nickel and lead smelters: 0.2 g
Hg/tonne production of finished zinc, nickel and lead
new and expanding primary copper smelters: 1 g Hg/tonne of finished
copper
atmospheric emissions; for new installations additional mercury offset
program to ensure no “net” emission increases occur: a new facility will
recover and retire an amount of mercury equivalent to their annual
emissions.
Denmark
France
Germany
0.1 all installations if mass flow > 1 g/h; hourly average
0.05 primary and secondary production of lead, zinc and aluminium; if mass
flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1 mg/Nm³
0.05 all installations (general requirement); alternatively < 0.25 g/h
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
0.05 If mass flow of Hg is > 0.25 mg/m3
Switzerland
0.2 all installations if mass flow > 1 g/h
62
References
CEC 2005
Community Strategy Concerning Mercury. Commission of the European Communities,
COM(2005) 20 final
CCME 2000
Canada-wide Standards for Mercury Emissions. Canadian Council of Ministers of the Environment, Quebec, June 5-6, 2000
EC 2001
Ambient air pollution by mercury - Position Paper. European Communities, Luxembourg, 2001.
Environment Canada 2002
Multi-pollutant emission reduction analysis foundation (MERAF) for the base metals smelting
sector : final report. September 17, 2002.
Environment Canada 2006
Environmental Code of Practice for Base Metals Smelters and Refineries : Code of Practice,
Canadian Environmental Protection Act, 1999. First edition. March 2006.
EIPPCB 2001
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques in the Non Ferrous Metals Industries. European IPPC Bureau, Sevilla: December 2001.
Hatch Consulting 2002
Proposed Emissions Standards for Total Particulate Matter and Sulphur Dioxide for the Base
Metals Smelting Sector. Prepared for Environment Canada, March 2002.
Hatch Consulting 2004
Guidance Document for Management of Wastes from the Base Metals Smelting Sector. Prepared for Environment Canada, March 2004.
Miller and Jones, 2005
Mercury and Modern Gold Mining in Nevada. Greg Jones, Glenn Miller. Dept. of Natural Resources and Environmental Sciences. University of Nevada. October 24, 2005
UNEP 2002
Global Mercury Assessment. United Nations Environment Programme, UNEP Chemicals, Geneva, December 2002.
63
64
CEMENT INDUSTRY
Background
157. This category covers installations for the production of cement clinker in rotary kilns with
a production capacity exceeding 500 tonnes per day, or in other furnaces with a production
capacity exceeding 50 tonnes per day. According to annex III of the Protocol, BAT are considered for fossil fuel fired kilns. The co-incineration of waste in cement kilns is treated within the
waste incineration category.
158. According to Annex III, in terms of energy demand and emission control opportunities,
rotary kilns with cyclone preheaters are preferable for clinker production. For heat recovery
purposes, rotary kiln off-gases are conducted through the preheating system and the mill dryers (where installed) before being dedusted, and the collected dust is returned to the feed material. Based on annex III, less than 0.5% of lead and cadmium entering the kiln is released in
exhaust gases. The high alkali content and the scrubbing action in the kiln favour metal retention in the clinker or kiln dust. The emissions of heavy metals into the air can be reduced by, for
instance, taking off a bleed stream and stockpiling the collected dust instead of returning it to
the raw feed. However, in each case these considerations should be weighed against the consequences of releasing the heavy metals into the waste stockpile. Another possibility is the hotmeal bypass, where calcined hot-meal is in part discharged right in front of the kiln entrance
and fed to the cement preparation plant. Alternatively, the dust can be added to the clinker.
Another important measure is a very well controlled steady operation of the kiln in order to
avoid emergency shut-offs of the electrostatic precipitators (ESPs). It is important to avoid high
peaks of heavy metal emissions in the event of such an emergency shut-off. To reduce direct
dust emissions from crushers, mills, and dryers, fabric filters (FFs) are mainly used, whereas
kiln and clinker cooler waste gases are controlled by fabric filters or electrostatic precipitators.
With ESP, dust can be reduced to concentrations below 50 mg/m3. When FF are used, the
clean gas dust content can be reduced to 10 mg/m3 (273 K, 101.3kPa, dry gas).
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
159. The selected process has a major impact on the energy use and air emissions from the
manufacture of cement clinker. For new plants and major upgrades, according to the BREF,
the best available technique for the production of cement clinker is considered to be a dry process kiln with multi-stage preheating and precalcination. Based on the BREF document, the
associated BAT heat balance value is 3000 MJ/tonne clinker. It is expected that all the non-dry
kilns will convert to the dry method when they are renewed
160. The best available techniques for the manufacturing of cement with regard to particulate
matter (PM) and heavy metals emissions includes the following general primary measures:
A smooth and stable kiln process, operating close to the process parameter set points, is
beneficial for all kiln emissions as well as the energy use.
Minimising fuel energy use.
Careful selection and control of substances entering the kiln can reduce emissions. When
practicable selection of raw materials and fuels with low contents of sulphur, nitrogen, chlorine, metals and volatile organic compounds should be preferred.
65
161. Fugitive emission sources mainly arise from storage and handling of raw materials, fuels
and clinker and from vehicle traffic at the manufacturing site. A simple and linear site layout is
advisable to minimise possible sources of fugitive dust. Proper and complete maintenance of
the installation generally has the indirect result of reducing fugitive PM by reducing air leakage
and spillage points. The use of automatic devices and control systems also helps fugitive dust
reduction, as well as continuous trouble-free operation.
162. Some techniques for fugitive PM abatement are:
Open pile wind protection. Outdoor storage piles of dusty materials should be avoided, but
when they do exist it is possible to reduce fugitive dust by using properly designed wind
barriers.
Water spray and chemical dust suppressors. When the point source of dust is well localised
a water spray injection system can be installed.
Paving areas used by lorries, road wetting and housekeeping.
Mobile and stationary vacuum cleaning. During maintenance operations or in case of trouble with conveying systems, spillage of materials can take place. To prevent the formation
of fugitive dust during removal operations, vacuum systems should be used.
Ventilation and collection in fabric filters. As far as possible, all material handling should be
conducted in closed systems maintained under negative pressure. The suction air for this
purpose is then de-dusted by a fabric filter before emitted into the atmosphere.
Closed storage with automatic handling system. Clinker silos and closed fully automated
raw material storage are considered the most efficient solution to the problem of fugitive
dust generated by high volume stocks. These types of storage are equipped with one or
more fabric filters to prevent fugitive dust formation in loading and unloading operations.
163. According to the BREF, BAT for reducing dust emissions are the combination of the
above described general primary measures and:
a) Minimisation/prevention of dust emissions from fugitive sources
b) Efficient removal of particulate matter from point sources by application of:
Electrostatic precipitators with fast measuring and control equipment to minimise the
number of carbon monoxide trips
Fabric filters with multiple compartments and ‘burst bag detectors’
164. In contrast to the BAT description in the HM Protocol, according to the BREF, the BAT
emission level for dust associated with these techniques is 20-30 mg/m³ on a daily average
basis. This emission level can be achieved by electrostatic precipitators and/or fabric filters at
the various types of installations in the cement industry. The best installations achieve emission
levels below 10 mg/m³ (273 K, 101.3 kPa, 10% oxygen, dry gas).
165. In general, available information indicates that there is no major difference in heavy metal
emissions between the different process types (e.g. wet or dry kilns), or between kilns burning
different fuels (e.g. conventional fuels or waste derived fuels). This is because it is the raw material input and not the process type which has the greater effect on heavy metal emissions.
Mercury is primarily introduced into the kiln with raw-materials (usually about 90% of the mercury is in the material input) with generally a minor amount (about 10%) coming from the fuels.
166. The best way to reduce heavy metal emissions is to avoid using feed materials with a
high content of volatile metals such as mercury. Mercury can build up over time in the cement
kilns dust, which is usually returned to the kiln system. When high build-ups occur in the dust,
emissions may increase. This can be remedied by discarding the cement kiln dust rather than
returning it to the raw material. As metals are often bound to dust, particulate abatement methods will help to reduce HM emissions.
66
Emerging techniques
167. Fluidised bed cement manufacturing technology: This process is expected to reduce heat
use by 10-12%.
168. A way to minimize mercury emissions is to lower the exhaust temperature. When high
concentrations of volatile metals (especially mercury) occur, adsorption on activated carbon is
an option.
169. The energy content of emissions can be reduced further by replacing clinker in cement by
slag from the production of iron (BOF slag). For more information: http://www.ecocem.ie and
http://www.epa.gov/epaoswer/non-hw/procure/products/cement.htm
Emission Limit Values
170. The Protocol on Heavy Metals includes an ELV for particulate emissions for the production of cement of 50 mg/m³ (273 K, 101.3 kPa, dry gas). No ELV is specified for the heavy metals covered by the Protocol.
171. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
Table 9:
Country
ELVs for cement industry (in mg/Nm³ unless stated otherwise)
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
50 continuous (daily) and discontinuous measurements (hourly average)
Austria8
50 continuous (daily) and discontinuous measurements (half-hour average) (10% O2)
Belgium
150 all installations if mass flow ≤ 500 g/h
50 all installations if mass flow > 500 g/h
continuous measurements, daily average.
Bulgaria
50
Czech
Republic
50
Germany
20 10% O2; continuous (daily) and discontinuous measurements (half-hour
average)
8
The regulation is under revision, with the aim to reach an adjustment to the state of the art.
67
Netherlands
Slovakia
Switzerland
United
States of
America
BAT according to BREF
document
15 8 hour average
50
50 all installations if mass flow > 0.5 kg/h
The ELV for new and existing installations = 0.15kg of PM per Mg of
feed (dry basis) to kiln, based on continuous basis.
20-30 These are the reported achievable concentrations with application of
BAT from European BREF documents, at 10 % O2, daily average
ELV for Cd emissions
Austria
0.1 discontinuous measurements (half-hour average)
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
France
0.2 common ELV for Cd, Ti, Hg
Germany
0.05 10% O2; alternatively < 0.15 g/h
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds; continuous (daily)
and discontinuous measurements (half-hour average)
Switzerland
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
Austria
1 common ELV for Pb, Co, Ni, As; discontinuous measurements (halfhour average)
Belgium
5 all installations if mass flow ≥ 25 g/h; common ELV for Sb, Pb, Cr, Co,
Cu, Mn, Pt, V, Sn and their compounds. Discontinuous measurements.
Denmark
1 all installations if mass flow > 5 g/h; hourly average
France
Germany
5 common ELV for Sb, Cr, Cu, Sn, Mn, Pb, V, Zn
0.5 10% O2; common ELV for Pb, Co, Ni, Se, Te and their compounds;
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
1 8 hour average
Switzerland
5 all installations if mass flow > 25 g/h
ELV for Hg emissions
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Denmark
0.1 all installations if mass flow > 1 g/h; hourly average
France
Germany
Netherlands
Switzerland
0.2 common ELV for Cd, Ti, Hg
0.05 10% O2; alternatively < 0.25 g/h; continuous (daily) and discontinuous
measurements (half-hour average)
0.05 8 hour average
0.2 all installations if mass flow > 1 g/h
68
References
EC 2001
Economic Evaluation of Air Quality Targets for Heavy Metals. European Commission, Entec
UK Limited, January 2001.
EC 2001a
Ambient air pollution by mercury - Position Paper. European Communities, Luxembourg, 2001.
Environment Canada 2004
Foundation Report on the Cement Manufacturing Sector. December, 2004.
EIPPCB 2001
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques in the Cement and Lime Manufacturing Industries. European IPPC Bureau, Sevilla: December 2001.
U.S. EPA, 1999
National Emission Standards for Hazardous Air Pollutants for Portland Cement Manufacturing
Industry; Final Rule, 64 Federal Register 31898. United States Environmental Protection
Agency. 14 June 1999.
69
70
GLASS INDUSTRY
Background
172. This category covers installations for the manufacture of glass using lead in the process
with a melting capacity exceeding 20 tonnes per day. According to annex III, best available
techniques (BAT) are considered for the production of glass using lead in the process, including the recycling of lead containing glass.
173. Lead is used in fluxes and colouring agents in the frit industry, in some special glasses
(e.g. coloured glasses, CRT funnels) and domestic glass products (lead crystal glasses). External cullet is an important source of metal contamination particularly for lead.
174. According to annex III, dust emissions stem mainly from batch mixing, furnaces, diffuse
leakages from furnace openings, and finishing and blasting of glass products. They depend
notably on the type of fuel used, the furnace type and the type of glass produced. Oxy-fuel
burners can reduce waste gas volume and flue dust production by 60%. The lead emissions
from electrical heating are considerably lower than from oil/gas-firing. During the melting cycle
using discontinuous furnaces, the dust emission varies greatly. The dust emissions from crystal
glass tanks (<5 kg/Mg melted glass) are higher than from other tanks (<1 kg/Mg melted soda
and potash glass). Some measures to reduce direct metal-containing dust emissions are: pelleting the glass batch, changing the heating system from oil/gas-firing to electrical heating,
charging a larger share of glass returns in the batch, and applying a better selection of raw
materials (size distribution) and recycled glass (avoiding lead-containing fractions). Exhaust
gases can be cleaned in fabric filters, reducing the emissions below 10 mg/m3. With electrostatic precipitators 30 mg/m3 is achieved.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
175. Related to the category description, the production of container glass, flat glass, domestic
glass, special glass and frits may be of concern, due to the potential use of lead oxides as raw
material or the use of cullet that may comprise lead containing glasses. The BATs described in
this subsection are primarily based on the European BAT reference (BREF) document
(EIPPCB, 2001) and are valid for the production of all these types of glass mentioned if not
stated otherwise.
Materials Storage and Handling
176. Bulk powder materials are usually stored in silos, and emissions can be minimised by
using enclosed silos, which are vented to suitable dust abatement equipment such as fabric
filters. Where practicable collected material can be returned to the silo or recycled to the furnace. Where the amount of material used does not require the use of silos, fine materials can
be stored in enclosed containers or sealed bags. Stockpiles of coarse dusty materials can be
stored under cover to prevent wind born emissions. Where dust is a particular problem, some
installations may require the use of road cleaning vehicles and water damping techniques.
71
177. Where materials are transported by above ground conveyors some type of enclosure to
provide wind protection is necessary to prevent substantial material loss. These systems can
be designed to enclose the conveyor on all sides. Where pneumatic conveying is used it is important to provide a sealed system with a filter to clean the transport air before release. To reduce dust during conveying and "carry-over" of fine particles out of the furnace, a percentage
of water can be maintained in the batch, usually 0 - 4 %.
178. An area where dust emissions are common is the furnace feed area. The main techniques for controlling emissions in this area are:
Batch moisture.
Slight negative pressure within the furnace (only applicable as an inherent aspect of operation).
Provision of extraction, which vents to a filter system, (common in cold top melters).
Enclosed screw feeders.
Enclosure of feed pockets (cooling may be necessary).
179. In potentially very dusty areas such as batch plants the buildings can be designed with
the minimum of openings and doors, or dust curtains can be provided where necessary. In the
furnace buildings it is often necessary to ensure a degree of natural cooling and so vents etc
are provided. It is important to ensure a good standard of house keeping and that all dust control measures (seals, extraction etc.) are properly functioning.
180. Areas of the process where dust is likely to be generated (e.g. bag opening, frit batch
mixing, fabric filter dust disposal, etc) can be provided with extraction which vents to suitable
abatement plant. This can be important at smaller installations where a higher degree of manual handling takes place. All of these techniques are particularly relevant where more toxic raw
materials are handled and stored, e.g. lead oxide.
Particulate matter and heavy metals
181. In general, BAT for controlling dust emissions from furnaces in the glass industry is the
use of either an electrostatic precipitator (ESP) or fabric filter system, operating where appropriate, in conjunction with a dry or semi-dry acid gas scrubbing system. The BAT emission level
for dust associated with these techniques is 5 - 30 mg/Nm³ which generally equates to less
than 0.1 kg/tonne of glass melted. Values in the lower part of the range given would generally
be expected for bag filter systems. In some cases, the application of BAT for metals emissions
may result in lower emission levels for dust. Secondary dust abatement represents BAT for
most glass furnaces, unless equivalent emissions can be achieved with primary measures.
182. Glass manufacturing facilities in the US typically control PM emissions using an ESP, or a
fabric filter (FF) using acid and temperature resistant filters. Acid gases are controlled using a
Dry Injection FF/ Dry Lime Scrubber combination, or a wet scrubber. U.S. EPA has found that
ESPs are most effective for reduction of heavy metals in furnace gases. ESPs achieve about
95% reduction in fine PM and metal fumes, and can easily handle the high temperature gases
from furnaces. Although generally a FF is expected to achieve at least 99% efficiency for removal of PM, this level is not achieved at the high temperatures and fine PM characteristic of
the glass manufacturing industry. However, a FF can be engineered to achieve similar results
(e.g., fitted with high-temperature resistant, acid gas resistant filters).
72
183. In general in this sector, BAT is considered to be raw material selection to minimise emissions of heavy metals, combined with acid gas scrubbing and dust abatement, where appropriate. The emission level associated with BAT for metals including lead (As, Co, Ni, Se, Cr, Sb,
Pb, Cu, Mn, V, Sn) is <5 mg/ Nm³.
Domestic Glass
184. In general and where it is economically viable, predominantly electrical melting is considered BAT for lead crystal, crystal glass and opal glass production, since this technique allows
efficient control of potential emissions of volatile elements. Where crystal glass is produced
with a less volatile formulation, other techniques may be considered when determining BAT for
a particular installation.
Downstream processes
185. For the production of container glass, the main potential source of emissions from downstream processes is hot end coating treatment. A number of techniques can be used to treat
emissions. Hot end treatment fumes may also be treated with the furnace waste gases in a
common acid gas/dust abatement system. The emission level associated with BAT is < 20
mg/Nm3 for particulate matter (PM).
186. For flat glass processing, a number of techniques can be used to treat downstream emissions. The emission levels associated with BAT are < 20 mg/Nm3 for particulates and <5
mg/Nm³ for metals including lead (As, Co, Ni, Se, Cr, Sb, Pb, Cu, Mn, V, Sn).
187. Potential emissions from downstream processes in the domestic glass sector consist
mainly of dust and acid gas fumes from lead crystal and crystal glass production. For potentially dusty activities BAT is considered to be cutting under liquid where practicable, and if dry cutting or grinding is carried out then extraction to a bag filter system. The emission level associated with BAT for particulates is <10 mg/Nm³, and for metals including lead (As, Co, Ni, Se, Cr,
Sb, Pb, Cu, Mn, V, Sn) is <5 mg/Nm³.
188. For the production of special glass, the emissions associated with downstream processing can be very variable and a wide range of primary and secondary techniques can be
used. For potentially dusty activities BAT is considered to be dust minimisation by cutting,
grinding or polishing under liquid, or where dry operations are carried out extraction to a bag
filter system. The emission level associated with BAT for particulates as well as for metals including lead (As, Co, Ni, Se, Cr, Sb, Pb, Cu, Mn, V, Sn) is <5 mg/Nm³.
189. In frits production, the only likely emission from downstream processes is dust and BAT is
considered to be the use of a bag filter system. The emission levels associated with BAT are
considered to be 5 - 10 mg/Nm3 for particulate and <5 mg/Nm3 for metals (As, Co, Ni, Se, Cr,
Sb, Pb, Cu, Mn, V, Sn).
73
Emerging techniques
190. The Plasma Melter makes use of the electrical conductivity of molten glass and operates
with negligible dust emissions. It is however not expected to be a viable technique for melting
within the foreseeable future.
Emission Limit Values
191. The Protocol on Heavy Metals includes an emission limit value (ELV) for lead emissions
for the production of glass of 5 mg/m³. No ELV is specified for particulate emissions nor for the
emissions of cadmium and mercury.
192. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
Table 10:
Country
ELVs for glass industry (in mg/Nm³ unless stated otherwise)
ELV
Remarks
ELVs for particulate matter (PM) emissions
Austria
50 O2 reference: 8% flame heated tanks; 13% day tanks; actual O2 electric furnaces; 21% Oxy fuel melting; continuous (daily) and discontinuous measurements (half-hour average)
Belgium
50 continuous measurements, daily average.
Germany
20 melting capacity >20 t/d;
8% O2 for flame-heated glass melting furnaces, 13% O2 for flame-heated pot
furnaces and day tanks, special provisions for oxygen fuel fired and electrically
heated glass melting tanks; continuous (daily) and discontinuous meas-
urements (half-hour average)
Netherlands
Switzerland
United
States of
America
5-30 equates to < 0,1 kg/tonne of glass melted
50 all installations if mass flow > 0.5 kg/h
0.1-0.13 g PM per The ELVs for lead glass manufacturing installations built after 1980 are
Kg glass produced 0.1 g PM per kg glass produced (0.1 g/Kg) for furnaces with gaseous
fuel and 0.13 g/Kg for furnaces with liquid fuel (U.S. EPA, 1980).
74
BAT according to BREF
document
5-30 furnaces; equates to < 0.1 kg/tonne of glass melted;
< 20 downstream processes: container glass, flat glass
< 10 downstream processes: domestic glass
5-10 downstream processes: frits
These values are considered the achievable concentrations by using
BAT as defined in the BREF document EIPPCB, 2001); 8 Vol% O2
continuous melters, 13 Vol% O2 discontinuous melters (except oxy-fuel
fired systems)
ELV for Cd emissions
Austria
0.1 O2 reference: 8% flame heated tanks; 13% day tanks; actual O2 electric furnaces; 21% Oxy fuel melting; discontinuous measurements (half-hour average)
Belgium
0.2 special glass
5 other glass; common ELV for Cr, Vi, Pb, Cd, Sb, Ni, Co, Se, V;
discontinuous measurements.
France
Germany
0.05 if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1 mg/Nm³
0.05 other glass, alternatively < 0.15 g/h
0.5 container glass,
common ELV for Cd and As and their compounds, Benzo(a)pyren,
water soluble Co compounds, Cr(VI) compounds
0.2 ELV for Cd only; if cadmium compounds are used as colouring agents
for quality reasons and Cd mass flow < 0.5 g/h;
Melting capacity >20 t/d; 8% O2 for flame-heated glass melting furnaces,
13% O2 for flame-heated pot furnaces and day tanks, special provisions for
oxygen fuel fired and electrically heated glass melting tanks; continuous (dai-
ly) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
0.05 If mass flow of Cd is > 0.25 mg/m3
0.1 all installations if mass flow > 0.5 g/h
ELV for Pb emissions
Protocol
(Annex V)
Austria
5
continuous (daily) and discontinuous measurements (hourly average)
5 Common ELV for Cd, As, Co, Ni, Se, Sb, Pb, Cr, Cu, Mn; O2 reference: 8%
flame heated tanks; 13% day tanks; actual O2 electric furnaces; 21% Oxy fuel
melting; discontinuous measurements (half-hour average)
Belgium
5 special glass
5 other glass; common ELV for Cr, Vi, Pb, Cd, Sb, Ni, Co, Se, V;
discontinuous measurements.
Denmark
France
1 all installations if mass flow > 5 g/h; hourly average
3 CRT funnels
1 other glass
if mass flow Pb and its compounds > 5 g/h
75
Germany
0.5
3 if lead is required for product quality
common ELV for Pb, Co, Ni, Se, Te and their compounds;
0.8 ELV for Pb and its compounds only; container glass using foreign cullet; additionally common ELV for Pb, Co, Ni, Se, Te and their compounds < 1.3 mg/Nm³
Melting capacity >20 t/d; 8% O2 for flame-heated glass melting furnaces, 13% O2 for flame-heated pot furnaces and day tanks, special provisions for oxygen fuel fired and electrically heated glass melting tanks;
continuous (daily) and discontinuous measurements (half-hour average)
Netherlands
Switzerland
BAT according to the
BREF
0.5 If mass flow of Pb is > 2.5 mg/m3
5 all installations if mass flow > 25 g/h
< 5 These values are considered the achievable concentrations by using
BAT as defined in the BREF document EIPPCB, 2001); Common BAT
level for As, Co, Ni, Se, Cr, Sb, Pb, Cu, Mn, V, Sn; furnaces and down
stream processes; at 8 % O2 by volume for continuous melters and 13
% O2 by volume for discontinuous melters (except oxy-fuel fired systems)
ELV for Hg emissions
Belgium
0.2 all installations if mass flow ≥ 1 g/h; common ELV for Cd, Hg, Th and
their compounds. Discontinuous measurements.
Denmark
0.1 all installations if mass flow > 1 g/h; hourly average
France
Germany
0.05 basic oxygen furnace if mass flow Cd+Hg+Tl > 1 g/h; additional common ELV of 0.1 mg/Nm³
0.05 melting capacity >20 t/d;; alternatively < 0.25 g/h
8% O2 for flame-heated glass melting furnaces, 13% O2 for flameheated pot furnaces and day tanks, special provisions for oxygen fuel
fired and electrically heated glass melting tanks; continuous (daily) and
discontinuous measurements (half-hour average)
Netherlands
0.05 If mass flow of Hg is > 0.25 mg/m3
Switzerland
0.2 all installations if mass flow > 1 g/h
76
References
EIPPCB 2001
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques in the Glass Manufacturing Industry. European IPPC Bureau, Sevilla: December 2001.
Marinshaw and Parrish, 2006
Characterization of the Glass Manufacturing Industry for Glass Manufacturing Area Source
NESHAP (Draft). Memorandum from R. Marinshaw and K. Parrish, of Research Triangle Institute to Susan Fairchild, of U.S. Environmental Protection Agency. May 5, 2006.
U.S. EPA, 1980
New Source Performance Standard (NSPS). United States Environmental Protection Agency.
60 Code of Federal Regulations (CFR) Subpart CC. Standards of Performance for Glass
Manufacturing Plants. 1980.
77
78
CHLOR-ALKALI INDUSTRY
Background
193. This category covers installations for chlor-alkali production by electrolysis using the mercury cell process.
194. The use of mercury-cell technology has been declining in Europe and North America over
the past few decades, as many such plants have shut down or been converted to non-mercury
processes. Moreover, European and North American producers are committed to not building
any new mercury-cell facilities. In addition, North American and European regulations do not
allow the construction of these facilities. The total phase-out of the mercury process for chloralkali production by the year 2010 was recommended by the Commission for the Protection of
the Marine Environment of the North-East Atlantic (OSPARCOM) in its PARCOM decision 90/3
of 14 June 1990, which was reviewed in 1999-2001 without any changes.
195. According to Best Available Techniques (BATs) as described in annex III, with regard to
emissions into air, Hg diffusely emitted from the cells to the cell room are particularly relevant.
Preventive measures and control are of great importance and should be prioritized according to
the relative importance of each source at a particular installation. In any case specific control
measures are required when mercury is recovered from sludges resulting from the process.
The following measures can be taken to reduce emissions from existing mercury process
plants:
Process control and technical measures to optimize cell operation, maintenance and more
efficient working methods;
Coverings, sealings and controlled bleeding-off by suction;
Cleaning of cell rooms and measures that make it easier to keep them clean; and
Cleaning of limited gas streams (certain contaminated air streams and hydrogen gas).
Based on Annex III, these measures can cut mercury emissions to values well below 2.0 g/Mg
of Cl2 production capacity, expressed as an annual average. There are examples of plants that
achieve emissions well below 1.0 g/Mg of Cl2 production capacity. The membrane process
results in no direct mercury emissions. Moreover, the global energy balance shows a slight
advantage for membrane cell technology in the range of 10 to 15% and a more compact cell
operation. It is, therefore, considered as the preferred option for new plants. PARCOM decision
90/3 of 14 June 1990 of the Commission for the Prevention of Marine Pollution from Landbased Sources (OSPARCOM) recommends that existing mercury cell chlor-alkali plants should
be phased out as soon as practicable with the objective of phasing them out completely by
2010. As a result of PARCOM decision 90/3, existing mercury-based chlor-alkali plants were
required to meet the level of 2 g of Hg/Mg of Cl2 by 31 December 1996.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
196. The selected process technology has a major impact on the energy use and emissions
from the manufacture of chlor-alkali. According to the BREF, best available techniques for the
production of chlor-alkali is considered to be membrane technology. Non-asbestos diaphragm
technology can also be considered as BAT.
79
197. Mercury releases from chlor-alkali operations can be entirely eliminated only by converting to a non-mercury process such as the membrane cell process. Conversion to membrane
cell technology is considered as BAT in the BREF document for chlor-alkali production under
the IPPC Directive. Conversions and closures of mercury-cell chlor-alkali plants are being carried out faster in some OSPARCOM countries than in others.
198. Among OSPARCOM countries and in the EU there has been considerable discussion
about the possible impacts the re-marketing of the mercury from decommissioned chlor-alkali
facilities will have on the global mercury market. In 1999 all West European chlor-alkali producers presented the authorities with a voluntary commitment, one clause of which commits
them not to sell or transfer mercury cells after plant shutdown to any third party for re-use. Euro
Chlor signed an agreement with the state-owned Miñas de Almadén of Spain. This agreement
stipulates that Miñas de Almadén will accept all surplus mercury from western European chlorine producers, under the condition that it displaces, ton for ton, mercury that would otherwise
have been newly mined and smelted to satisfy legitimate uses. As a pro-active contribution to a
proposed globally organised effort to phase out primary production of mercury and to stop surpluses re-entering the market, the Commission intends to propose an amendment to Regulation (EC) No. 304/2003 to phase out the export of mercury from the Community by 2011. In
North America, to reduce supply, the US Government decided in 2004 to place a large quantity
of previously stockpiled mercury into long-term storage (at least 40 years) to prevent it from
entering the market (U.S. DNSC, 2004).
199. During the remaining life of mercury cell plants, all possible measures should be taken to
protect the environment as a whole including:
a) Minimising mercury losses to air by:
use of equipment and materials and, when possible, a lay-out of the plant (for example,
dedicated areas for certain activities) that minimise losses of mercury due to evaporation and/or spillage
good housekeeping practices and good maintenance routines
collection and treatment of mercury-containing gas streams from all possible sources,
including hydrogen gas. Sulphur impregnated activated charcoal was used by ICI
Cornwall for the hydrogen filters.
reduction of mercury levels in caustic soda
According to the BREF, the best performing mercury cell plants are achieving total mercury
losses to air, water and with products in the range of 0.2-0.5 g Hg per tonne of chlorine capacity as a yearly average, and with regard to air emissions 0.21-0.32 g Hg/Mg Cl2. In the
following table mercury emissions from best performing plants in Europe are indicated.
Air emissions from
g Hg/tonne chlorine capacity
cell room
0.2-0.3
process exhausts, including Hg distillation unit
0.0003-0.01
untreated cooling air from Hg distillation unit
0.006-0.1
hydrogen gas
<0.003
b) Minimising current and future mercury emissions from handling, storage, treatment and
disposal of mercury-contaminated wastes by:
implementation of a waste management plan drawn up after consultation with the appropriate authorities
minimising the amount of mercury-containing wastes
recycling the mercury contained in wastes when possible
treatment of mercury-contaminated wastes to reduce the mercury content in the wastes
80
stabilisation of residual mercury-contaminated wastes before final disposal.
c) Decommissioning carried out in a way that prevents environmental impact during and after
the shutdown process as well as safeguarding human health
200. Major points of mercury emission generation in the mercury cell process of chlor-alkali
production include: byproduct hydrogen stream, end box ventilation air, and cell room ventilation air. Typical devices/techniques for removal of mercury in these points are:
gas stream cooling to remove mercury from hydrogen stream,
mist eliminators,
scrubbers, and
adsorption on activated carbon and molecular sieves.
The installation of the above mentioned devices can remove mercury with the efficiency of
more than 90 %.
201. However, most mercury losses from chlor-alkali facilities are fugitive. Relevant preventive
measures include:
Equipment cool-down before opening for invasive maintenance;
Consolidation of maintenance actions to minimize the number of invasive maintenance
events;
Draining mercury from components before they are opened or keeping the internal mercury
covered with cooling water or installing a hood to capture mercury vapour;
Capital investment in larger-capacity decomposers that require less invasive maintenance;
Improving the purity of brine so as to prevent build-up of mercury wastes that require invasive maintenance;
Use of longer-lasting metallic anodes that necessitate less invasive maintenance; DSA’s
were used in Canada: Dimensionally Stable Anodes (DSA) replaced graphite (carbon) anodes that were the cause of many chlorinated organic substances released
Capital investment in new elongated cells with air pollution prevention features like internal
mechanical arms that can accomplish some maintenance actions that formerly required invasive maintenance.
202. In the U.S. regulation for chlor-alkali plants there are no ELVs for “total” emissions from
these facilities or for “cell rooms.” Instead, stringent workplace standards are required in U.S. to
minimize emissions from cell rooms or, as an alternative, facilities can implement a cell room
monitoring program. Also, the U.S. regulation does include ELVs for certain vents, as shown in
the ELV table below. The stringent work place practices to reduce emissions, include:
a) Use of specific equipment (e.g., smooth interior pipes, fixed covers, head space routed to
ventilation system etc....)
b) Preventive Operations (e.g., cool electroplate and decomposer before opening, keep mercury covered with aqueous liquid at temperature below its boiling point, and gas stream
cooling to remove mercury from hydrogen stream). For more details see the U.S. regulation (U.S. EPA, 2003).
203. Based on OSPAR 2005, all plants comply with the limit value of 2 g Hg/t Cl2 for air emissions in PARCOM Decision 90/3, and it is clear that in many plants, air emissions continue to
fall. However, for reported emissions a wide range in actual values from 0.14 to 1.57 g Hg/t Cl2
is shown.
81
Emerging techniques
204. Fundamental research programmes related to mercury technology are not being developed since it is very unlikely that any new mercury plants will be built. The only recent improvements in mercury cells concern the anode geometry with the aim of improving gas release in order to decrease electrical energy usage and increase anode coating life.
Emission Limit Values
205. The Protocol on Heavy Metals includes an emission limit value (ELV) for mercury for new
chloralkali plants of 0.01 grams of mercury per metric tonne of chlorine production capacity (i.e.
0.01 g Hg/tonne Cl2). However, no ELVs for mercury emissions from existing plants are specified in the Protocol. Instead, the Protocol requires Parties to evaluate ELVs for existing chloralkali plants within two years after the date of entry into force of the Protocol. A separate summary of emission limit values and control for the chlor-alkali industry with regard to mercury
emissions from existing plants was submitted to WGSR at its 37th session in 2005
(EB.AIR/WG.5/2005/2 Annex I).
206. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in g Hg/Mg Cl2 production (capacity) as
an annual mean value, referring to standard conditions (273.15 K, 101.3 kPa, dry gas), and do
not cover start-up and shutdown periods except stated otherwise.
Table 11:
Country or
other reference
ELVs for chlor-alkali plants (in g Hg/tonne chlorine capacity unless stated otherwise)
ELV
Remarks
ELVs for mercury (Hg) emissions
Protocol
(Annex V)
Belgium
0.01 new installations, total plant emissions
1.5 new installations;
2 existing installations;
additionally ELV of 0.2 mg/Nm 3 if mass flow  1 g/h
phase out of mercury cell process by 2010
Canada
5 existing installations, emissions from cell room
0.1 existing installations, emissions from hydrogen gas
0.1 existing installations, emissions from end boxes
0.1 existing installations, emissions from retorts/Hg recovery
additionally ELV of 1.68 kg Hg/day for total plant emissions
Czech
Republic
0.01 new installations
2 existing installations
82
Finland
phase out of mercury cell process by 2010
France
ELV of 0.05 mg Hg/Nm3 if mass flow Cd+Hg+Tl > 1 g/h; additional
common ELV of 0.1 mg/Nm³
Germany
1 existing installations;
1.2 existing installations if alkali lye and dithionite or alcoholates are produced simultaneously in one facility;
emissions from cell room and end boxes
Netherlands
Slovakia
Sweden
Switzerland
United
States of
America
1.5 phase out of mercury cell process by 2010
1.5
phase out of mercury cell process by 2010
ELV of 0.2 mg/m³ for all installations if mass flow > 1 g/h
0.0 ELV for total mercury emissions for new installations
0.076 ELV for mercury from hydrogen streams and end box ventilation systems for existing installations with end box ventilation based on 52
week average of Cl2 produced (not capacity);
0.033 ELV for mercury from hydrogen streams for existing installations without end box ventilation based on 52 week average of Cl2 produced.
For cell rooms, no numerical ELV is specified; however, stringent workplace standards are required to minimize emissions from cell rooms or,
as an alternative, facilities can implement a cell room monitoring program. Cell room ventilation emissions of below 1,3 kg/d may be assumed when the operator carries out the work practice standards.
Also, for all mercury recovery facilities with oven type thermal recovery
units, total mercury emissions are not to exceed 23 mg per normal cubic meter (mg/Nm³) from each unit vent; and for non-oven type mercury
thermal recovery units, emissions are not to exceed 4 mg/Nm³.
BAT according to BREF
document
0.21-0.32 existing installations, total plant emissions (air, water and products)
achievable with application of BAT from European BREF documents.
OSPARCOM
0.14-1.57 reported emissions of existing installations for 2003, phase out of the
mercury process for chlor-alkali production by 2010
References
CEC 2005
Community Strategy Concerning Mercury. Commission of the European Communities,
COM(2005) 20 final
EC 2001
Ambient air pollution by mercury - Position Paper. European Communities, Luxembourg, 2001.
83
EIPPCB 2001
Integrated Pollution Prevention and Control: Reference Document on Best Available Techniques in the Chlor-Alkali Manufacturing industry. European IPPC Bureau, Sevilla: December
2001.
OSPAR 2004
OSPAR Implementation Report Dec. 90/3: Overview Assessment of Implementation of
PARCOM Decision 90/3 on Reducing Atmospheric Emissions from Existing Chlor-Alkali Plants
- Update 2004. OSPAR Commission, 2004.
OSPAR 2005
Mercury Losses from the Chlor-Alkali Industry in 2003. OSPAR Commission, 2005.
UNEP 2002
Global Mercury Assessment. United Nations Environmental Programme. UNEP Chemicals,
December 2002.
U.S. DNSC, 2004.
Mercury Management Environmental Impact Statement. United States Defense National
Stockpile Center (DNSC). 30 April 2004. 69 Federal Register 23733, 4/30/04.
U.S. EPA, 2003
NESHAP for Mercury Emissions from Mercury Cell Chlor-Alkali Plants; Final Rule 68 Federal
Register 70904 - 70946, United States Environment Protection Agency. December 19, 2003.
84
MUNICIPAL, MEDICAL AND HAZARDOUS WASTE INCINERATION
Background
207. This sector covers installations for the incineration of hazardous or medical waste with a
capacity exceeding 1 tonne per hour and for the incineration of municipal waste with a capacity
exceeding 3 tonnes per hour, as well as installations for the co-incineration of municipal, medical and hazardous waste. According to annex III, besides emissions abatement measures
waste management strategies and alternative waste treatment methods are also considered.
208. There are wastes that are neither classified as hazardous, municipal or medical wastes,
depending on national legislation (e.g., non-hazardous industrial wastes, sludge etc.), and thus
are not currently taken into account according to annex II. These wastes may be incinerated as
well as co-incinerated in other industries, therefore potentially constituting a relevant source of
heavy metal emissions. Therefore, additional information is given for these type of wastes. Furthermore, there are other thermal waste treatment methods (e.g. pyrolysis) that are not currently taken into account in annex II but may be a relevant source of heavy metal emissions.
Therefore, additional information is given for these processes as well.
209. According to annex III, particular actions should be taken both before and after incineration to reduce the emissions of mercury, cadmium and lead. The best available technology
(BAT) for reducing particulate matters is considered to be fabric filters in combination with dry
or wet methods for controlling volatiles. Electrostatic precipitators (ESPs) in combination with
wet systems can also be designed to reach low particulate matters emissions, but they offer
fewer opportunities than fabric filters especially with precoating for adsorption of volatile pollutants. When BAT is used for cleaning the flue gases, the concentration of particulate matters
will be reduced to a range of 10 to 20 mg/m3; in practice lower concentrations are reached,
and in some cases concentrations of less than 1 mg/m3 have been reported. The concentration of mercury can be reduced to a range of 0.05 to 0.10 mg/m3, normalized to 11% O2).
Heavy metals are found in all fractions of the municipal waste stream (e.g. products, paper,
organic materials). Therefore, by reducing the quantity of municipal waste that is incinerated,
heavy metal emissions can be reduced. This can be accomplished through various waste
management strategies, including recycling programs and the composting of organic materials.
In addition, some UNECE countries allow municipal waste to be landfilled. In a properly managed landfill, emissions of cadmium and lead are eliminated and mercury emissions may be
lower than with incineration.
Best Available Techniques based on the EIPPCB BAT reference (BREF) document and
potential BATs from other recent publications
210. For BAT as well as in the Waste incineration Directive of the EU, no differentiation is
made between municipal, hazardous and medical waste in terms of applied techniques or
achievable emission limits (as all types of waste are often incinerated in the same installation).
211. The only relevant primary techniques for preventing emissions of mercury into the air before incinerating are those that prevent or control, if possible, the inclusion of mercury in waste.
In some countries mercury-containing components are separated out of the solid waste stream
and managed or recycled properly. Removing mercury from the waste stream before it enters
the incinerator is much more cost-effective than capturing mercury later from flue gases using
85
emissions control devices (e.g., carbon beds or activated carbon injection). Once present in the
waste stream, mercury contributes to the need for emission controls on incinerators, special
disposal of incinerator residues, landfill leachate treatment etc.
212. Lower emissions of mercury from municipal waste combustors and medical waste incinerators can be achieved through product substitution. Although this is potentially applicable to a
wide range of components, batteries have received the greatest attention because of their significant contribution to total mercury content in municipal and medical wastes. The applicability
of the product substitution to other areas should be based on technical and economic feasibility.
213. Non-technical measures for preventing and controlling mercury releases from waste
streams are:
prohibit mercury in product waste and in process waste from being released directly to the
environment, by means of an effective waste collection service; and
prohibit mercury in product waste and in process waste from being mixed with less hazardous waste in the general waste stream, by ensuring separate collection and treatment.
214. In general, BATs for reducing heavy metals and PM emissions are:
to establish and maintain quality controls over the waste input,
in order to reduce overall emissions, to adopt operational regimes and implement procedures (e.g. continuous rather than batch operation, preventative maintenance systems) in
order to minimise as far as practicable planned and unplanned shutdown and start-up operations,
the optimisation and control of combustion conditions
properly designed, maintained, and operated PM control devices
215. Mercury emissions from MWIs occur in two main forms: elemental mercury and ionic
mercury. Elemental mercury is not readily removed by conventional emission control devices
(such as electrostatic precipitators, fabric filters, scrubbers). However, ionic mercury is captured relatively well by some of these devices. Also, some mercury-specific technologies can
capture elemental mercury (such as sorbent injection). Therefore, in order for elemental mercury to be effectively controlled, it either has to be transformed into ionic mercury (which can then
be removed by a suitable conventional device) or mercury-specific capture technologies must
be applied. In the presence of chloride ions and at combustion chamber temperatures above
850°C a considerable part of mercury is present as HgCl2 in municipal waste incinerators.
216. Between 30 % and 60 % of mercury is retained by high efficiency ESPs or fabric filters
(FFs), and flue gas desulfurisation (FGD) systems capture further 10 to 20 %.
217. The following technologies may be used to filter out mercury from waste incinerators and
combustors:
Carbon filter beds have been developed for use as a final cleaning stage in waste incinerators and utility boilers to remove volatile heavy metals (e.g., mercury). Cost effectiveness
studies indicate US $513–$1,083 per pound mercury removed using carbon filter beds on
waste incinerators.
Wet scrubbing systems are available in different designs and can be used to control metals.
A 90 percent reduction of mercury is possible with a wet scrubber when additives are used.
Cost-effectiveness for this technology is estimated to be US $1,600–$4,000 per pound of
mercury removed for waste incineration.
86
-
Selenium filters have been developed to remove elemental mercury. Selenium filters are
effective on flue gas streams with inlet mercury concentrations of up to 9 mg/m³.
Activated carbon injection prior to the ESP or FF: test programs have shown mercury removals of 50 to 95 percent. The cost of removing mercury from MWCs using activated carbon injection is estimated to be US $211–$870 per pound and from Medical Waste Incinerators, US $2,000-$4000 per pound. Activated carbon injection is currently used to control
mercury emissions from four hazardous waste incinerators and capture efficiencies have
ranged from 80% to greater than 90%.
218. BAT is the use of an overall flue-gas treatment (FGT) system that, when combined with
the installation as a whole, generally provides for the operational emission levels listed in the
following table for releases to air associated with the use of BAT (in mg/Nm³):
noncontinuous
measurements
Total particulate matter
1/2 hour average
daily
average
1-20
1-5
In general the use of fabric filters give
the lower levels within these emission
ranges. Effective maintenance of dust
control systems is very important.
Energy use can increase as lower
emission averages are sought. Controlling dust levels generally reduces
metal emissions too.
0.001-0.03
0.001-0.02
Adsorption using carbon based reagents is generally required to achieve
these emission levels with many
wastes - as metallic Hg is more difficult to control than ionic Hg. The precise abatement performance and
technique required will depend on the
levels and distribution of Hg in the
waste. Some waste streams have very
highly variable Hg concentrations –
waste pretreatment may be required in
such cases to prevent peak overloading of FGT system capacity.
Mercury and
its compounds(as
Hg)
<0.05
Total cadmium and thallium (and their
compounds
expressed as
the metals)
0.005-0.05
See comments for Hg. The lower volatility of these metals than Hg means
that dust and other metal control
methods are more effective at controlling these substances than Hg.
sum other
metals
0.005 - 0.5
Techniques that control dust levels
generally also control these metals
87
219. If re-burn of flue gas treatment residues is applied, then suitable measures should be
taken to avoid the re-circulation and accumulation of Hg in the installation.
220. For the control of Hg emissions where wet scrubbers are applied as the only or main effective means of total Hg emission control:
the use of a low pH first stage with the addition of specific reagents for ionic Hg removal, in
combination with the following additional measures for the abatement of metallic (elemental) Hg, as required in order to reduce final air emissions to within the BAT emission
ranges given for total Hg
activated carbon injection,
activated carbon or coke filters,
221. For the control of Hg emissions where semi-wet and dry FGT systems are applied, the
use of activated carbon or other effective adsorptive reagents for the adsorption of Hg, with the
reagent dose rate controlled so that final air emissions are within the BAT emission ranges given for Hg.
222. Selective catalytic reduction (SCR) for control of nitrogen oxides also reduces mercury
emissions as a co-benefit by changing it into a form that can be collected by fabric filters.
223. Most Parties require discontinuous monitoring of mercury emissions only, while some
consider continuous monitoring as BAT; proven systems for continuous measurements of mercury emissions are available on the market.
224. According to the EU-landfill directive 1999/31 EU (version 20/11/2003) only pre-treated
waste may be landfilled in the EU-member states and specific requirements have to be fulfilled
(e.g. C-content). Under special conditions (e.g. low ph) heavy metals may be mobilized and
washed out from the landfills. Considering the integrated emissions, it can not generally be
stated, that the emissions from landfills are lower than those from incineration.
Co-incineration of waste and recovered fuel in cement kilns
225. The use of suitable wastes as raw materials can reduce the input of natural resources,
but should always be done with satisfactory control on the substances introduced to the kiln
process.
226. The use waste fuels may increase the input of metals into the process. As the metals
entering the kiln system are of varying volatility and because of the high temperature, the hot
gases in the cement kiln system contain also gaseous metal compounds. Mass balance investigations show that there is low retention of elements with high volatility in the clinker, resulting
in an accumulation of these substances in the kiln system.
227. Volatile metals in material that are fed at the upper end of the kiln or as lump fuel can
evaporate. These metals do not pass the primary burning zone and may not be decomposed or
bound in the cement clinker. Therefore the use of waste containing volatile metals (mercury,
thallium) can result in an increase of the emissions of mercury, thallium when improperly used.
228. In general, the BAT for cement kilns apply (see chapter "cement industry").
88
Co-incineration of waste and recovered fuel in combustion installations
229. Certain waste derived fuels may be co-combusted in regular combustion installations
such as power plants together with conventional fuels. These secondary fuels include materials
like e.g. animal by-products, organic acids, solvents, packing materials and plastics, fuels derived from waste (recovered fuels), sludge, tires, agricultural residues, demolition wood etc.
Waste derived fuels are mainly solid or liquid with a significant amount of ash. For this reason
co-combustion is more or less limited to the application in coal-fired boilers and fluidized bed
combustion systems.
230. In general, the BAT for combustion installations apply (see chapter "combustion of fossil
fuels in utility and industrial boilers").
231. Co-incineration in large combustion plants should not cause higher emissions than cocombustion in incineration plants. Large combustion plants, designed and operated according
to BAT, operate effective techniques and measures for the removal of dust, including partly
heavy metals, and other emissions. In general, these techniques can be seen as sufficient and
can, therefore, also be considered as BAT for the co-combustion of secondary fuel. The rationale as to which wastes can be used for co-combustion is based of the specifications of the
conventional fuel normally burned in the specific plant and its associated measured emission
levels. If the range of impurities of the waste, in particular the content of heavy metals, lies
within the same range as that from the normally used conventional fuel, the fuel specific BAT
applies also for the co-combustion of this secondary fuel. The first BAT choice in this respect is
also the careful selection of the type and mass flow of the secondary fuel, together with limiting
the percentage of the secondary fuel that can be co-combusted. With regard to heavy metals,
this encompasses to avoid Hg entering as an elevated component of the secondary fuel and,
when there are large quantities of secondary fuel with high concentrations of heavy metals (especially Hg), to use gasification of the secondary fuel and cleaning of the product gas. However, according to the waste used, the co-combustion of secondary fuel can lead to increased
emissions of heavy metals, in particular mercury. In this case the adaptation of flue-gas cleaning systems and the additional injection of activated carbon with an associated reduction rate of
70 – 85 % for mercury is BAT.
Emerging techniques
232. The PECK process for municipal solid waste treatment [EIPPCB 2005]: Before recirculating to the grate, fly ashes collected in the boiler and ESP are mixed with dewatered
sewage sludge and fed to a pelletiser. The resulting dry pellets are treated in a fluidised bed
reactor, where chlorination and evaporation of the metals take place at 900 °C. The evaporated
metals leave the fluidised bed reactor together with the flue-gas. By a partial quench the heavy
metals are condensed and filtered afterwards. The depleted fly ash, the re-circulate, is removed from the evaporation reactor and fed back through a buffer silo to the grate. The filtered
heavy metal concentrate is then transported to the zinc and lead refining industry. Heavy metals like zinc, lead, cadmium and copper are concentrated in the output flows hydroxide sludge,
ferrous and copper scrap. The heavy metals flow via the mineral product and the purified fluegas are negligible. The process has been developed for municipal solid wastes but could in
principle be applied to other wastes.
233. Heavy metal evaporation process: Fly ash is heated to around 900 ºC in an atmosphere
enriched with hydrochloric acid. The heavy metals are volatilised as chlorides and then condensed on a filter where they concentrate to such an extent that re-cycling may be possible.
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The remaining fly ash is thus cleaned and may be used for construction. When sited on an existing incineration site the flue-gases evolved may be treated in the existing FGT system, and
the HCl may be drawn from a wet scrubber. The process has not been demonstrated on a
commercial scale plant.
234. Hydro-metallurgical treatment + vitrification: In this process hydrometallurgical treatment
allows the removal of heavy metals and salts. The subsequent vitrification of the fly ash produces a slag which may be used for construction. The process is reported to be applicable to
several ash compositions and to have been demonstrated on a semi-industrial scale.
Emission Limit Values (ELVs)
235. The Protocol on Heavy Metals includes ELVs for particulate emissions of 10 mg/m³ for
hazardous and medical waste incineration and of 25 mg/m³ for municipal waste incineration,
and for mercury emissions of 0.05 mg/m³ for hazardous waste incineration and of 0.08 mg/m³
for municipal waste incineration (11% O2, daily average). No ELVs are specified for coincineration, for lead and cadmium emissions and for the emissions of mercury from medical
waste incineration. Instead, the Protocol requires Parties to evaluate ELVs for mercurycontaining emissions from medical waste incineration within two years after the date of entry
into force of the Protocol. A separate summary of emission limit values and control for medical
waste incineration with regard to mercury emissions was submitted to WGSR at its 37th session (EB.AIR/WG.5/2005/2 Annex II).
236. The following table gives an overview on current ELVs implemented by the Parties. Information was compiled using Parties’ responses to question 44 of the 2004 questionnaire on
Strategies and Policies for Compliance Review and additional information by national experts.
For comparison, the table also includes BAT associated emission levels as indicated in the
European BREF document. All values are expressed in mg/Nm³ referring to standard conditions (273.15 K, 101.3 kPa, dry gas) and do not cover start-up and shutdown periods except
stated otherwise.
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Table 12:
ELVs for municipal, medical and hazardous waste incineration (in mg/Nm³ unless stated
otherwise)
Country or
other reference
ELV
Remarks
ELV for PM emissions
Protocol
(Annex V)
10 hazardous and medical waste incineration
25 municipal waste incineration
11% O2; continuous (daily) and discontinuous measurements (hourly
average)
Austria
10 waste incineration (solid fuels: 11% O2, liquid fuels: 3% O 2)
10-20 co-incineration in cement kilns (≤ 40% thermal input, 10% O2) and coincineration in combustion installations ≤ 100 MW (≤ 40% thermal input); sliding scale ELV (≤ 40% thermal input)
10-15 co-incineration in combustion installations > 100 MW (≤ 40% thermal
input); sliding scale ELV (≤ 40% thermal input)
continuous measurements, daily average
Belgium
10 municipal, medical and hazardous waste incineration; continuous
measurements, daily average.
Bulgaria
10 hazardous waste incineration, 11% O2, daily average.
Czech
Republic
10 waste incineration, daily average
Germany
10 waste incineration (11% O2, waste oil and pyrolysis gas: 3% O2), coincernation in combustion installations (< 25% thermal input, solid fuels:
6% O2, liquid and gaseous fuels: 3% O2), co-incernation in cement and
lime kilns (> 60% thermal input, 11% O2, waste oil and pyrolysis gas:
3% O2; on demand: sliding scale ELV of 10-20 mg/m³ depending of the
amount of co-incinerated waste), co-incernation in other installations (>
25% thermal input)
20 co-incernation in cement kilns (< 60% thermal input, 10% O2), in existing combustion installations and if no desulphurication is necessary (<
25% thermal input, solid fuels: 6% O2, liquid and gaseous fuels: 3%
O2) and in other installations (< 25% thermal input);
continuous measurements; daily average
Netherlands
Slovakia
5 municipal, hazardous and medical waste incineration, 8 hour average
50 waste incineration, < 1 t/h
30 waste incineration, 1-3 t/h
20 waste incineration, > 3 t/h
Switzerland
10 waste incineration, 11% O2
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United
States of
America
BAT according to the
BREF
17
19
50
2.4 to 24
21 to 57
24
24
Municipal Waste Combustors (MWCs), new installations (11% O 2)
MWCs, existing installations > 9.5 tonnes/hr (11% O2)
MWCs, existing installations 1.4 to 9.5 tonnes/hr (11% O2)
Range for 5 types of hazardous waste combustors, new facilities.
Range for 5 types of hazardous waste combustors, existing facilities.
Medical Waste incinerators: new installations > 90.9 kg/hr (11% O 2)
Medical Waste Incinerators: existing installations > 227 kg/hr (11% O2).
1-5 waste incineration, daily average
ELV for Cd emissions
Austria
0.05 waste incineration and co-incineration ≤ 40% thermal input (solid fuels:
11% O2, liquid fuels: 3% O 2, cement kilns: 10% O2); half-hour average
Belgium
0.05 Flanders: Municipal, medical and hazardous waste incineration; common ELV for Cd, Tl; continuous (daily) and discontinuous measurements
0.2 Walloon: Municipal waste incineration (17% O2), medical waste incineration (9% O2)
0.5 Walloon: waste oil incineration
Bulgaria
Czech
Republic
Denmark
France
0.05 hazardous waste incineration, 11% O2, daily average.
0.1 combustion of waste oils
0.05 municipal waste incineration, discontinuous measurements
0.05 municipal, medical and industrial waste incineration; common ELV for
Cd, Tl
Germany
0.05 incineration and co-incernation of waste (> 25% thermal input, > 60%
for cement and lime kilns); common ELV for Cd and Tl and their compounds; common ELV for Cd and As and their compounds, Benzo(a)pyren, water soluble Co compounds, Cr(VI) compounds; common
ELV for Cd, As, Co, Cr and their compounds, Benzo(a)pyren; discontinuous measurements; 11% O2, waste oil and pyrolysis gas: 3% O2,
cement kilns: 10% O2, solid fuels: 6% O2, liquid and gaseous fuels: 3%
O2; minor co-incineration covered to sector-specific regulations
Netherlands
0.05 municipal, hazardous and medical waste incineration, common ELV for
Cd, Th; 8 hour average
Slovakia
United
States of
America
0.2 waste incineration; common ELV for Hg, Tl, Cd
0.03 MWCs, existing installations > 9.5 tonnes/hr (11% O2)
0.07 MWCs, existing installations 1.4 to 9.5 tonnes/hr (11% O2)
0.028 Medical Waste incinerators: new installations > 90.9 kg/hr (11% O 2)
0.113 Medical Waste Incinerators: existing installations > 227 kg/hr (11% O 2).
BAT according to the
BREF
0.005-0.05 waste incineration, common BAT value for Cd, Tl and their compounds;
discontinuous measurements
ELV for Pb emissions
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Austria
0.5 waste incineration and co-incineration ≤ 40% thermal input (solid fuels:
11% O2, liquid fuels: 3% O 2, cement kilns: 10% O2); common ELV for
Pb and 9 other HM; half-hour average
Belgium
0.5 Flanders: Municipal, medical and hazardous waste incineration; common ELV for Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V, Sn; continuous (daily)
and discontinuous measurements
5 Walloon: common ELV for Pb, Cr, Cu, Mn; municipal waste incineration
(17% O2), medical waste incineration (9% O2), waste oil incineration
Czech
Republic
1 combustion of waste oils
Denmark
0.5 municipal waste incineration; common ELV for As, Pb, Sb, Cr, Co, Cu,
Mn, Ni, V, discontinuous measurements
France
0.5 municipal, medical and industrial waste incineration; common ELV for
Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V
Germany
Netherlands
0.5 incineration and co-incernation (> 25% thermal input, > 60% for cement
and lime kilns) of waste; common ELV for Sb, As, Pb, Cr, Co, Cu, Mn,
Ni, V, Sn and their compounds; discontinuous measurements; 11% O2,
waste oil and pyrolysis gas: 3% O2, cement kilns: 10% O2, solid fuels:
6% O2, liquid and gaseous fuels: 3% O2; minor co-incineration covered
to sector-specific regulations
0.5 hazardous and medical waste incineration,
1 municipal waste incineration
common ELV for HM incl. Pb; 8 hour average
Slovakia
United
States of
America
5 waste incineration; common ELV for Pb, Cu, Mn
0.31 MWCs, existing installations > 9.5 tonnes per hour (11% O2)
1.2 MWCs, existing installations 1.4 to 9.5 tonnes per hour (11% O2)
0.05 Medical Waste incinerators: new installations > 90.9 kg/hr (11% O2)
0.85 Medical Waste Incinerators: existing installations > 227 kg/hr (11% O 2).
BAT according to the
BREF
0.005-0.5 waste incineration, common BAT value for other metals except Hg, Cd,
Tl and their compounds; discontinuous measurements
ELV for Hg emissions
Protocol
(Annex V)
0.05 hazardous waste incineration
0.08 municipal waste incineration
11% O2; continuous (daily) and discontinuous measurements (hourly
average)
Austria
0.05 waste incineration and co-incineration ≤ 40% thermal input (solid fuels:
11% O2, liquid fuels: 3% O 2, cement kilns: 10% O2); continuous (daily)
and discontinuous measurements (half-hour average)
Belgium
0.05 Flanders: municipal, medical and hazardous waste incineration; continuous (daily) and discontinuous measurements
0.2 Walloon: common ELV for Pb, Cr, Cu, Mn; municipal waste incineration
(17% O2), medical waste incineration (9% O2)
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Bulgaria
0.05 hazardous waste incineration, 11% O2, daily average.
Canada
0.02 municipal and medical waste incineration except conical waste combusters; new or expanding facilities of any size and existing facilities
except medical waste incineration < 120 Tonnes/year
0.05 hazardous waste incineration; new or expanding facilities of any size;
0.07 Sewage sludge incineration; new or expanding facilities of any size;
0.04 medical waste incineration < 120 Tonnes/year; existing facilities
0.05 hazardous waste incineration; existing facilities
0.07 Sewage sludge incineration; existing facilities
11% oxygen
Czech
Republic
0.08 municipal waste incineration
0.1 medical waste incineration
0.05 co-incineration in cement plants and combustion installations
Denmark
France
Germany
0.05 municipal waste incineration; discontinuous measurements
0.05 municipal, medical and industrial waste incineration
0.03 incineration of waste (11% O2, waste oil and pyrolysis gas: 3% O2), coincernation in cement and lime kilns (10% O2), co-incernation in combustion installations (solid fuels: 6% O2, liquid and gaseous fuels: 3%
O2), co-incernation in other installations
0.05 co-incernation in cement kilns (< 60% thermal input), if Hg due to raw
materials; 10% O2
continuous measurements; daily average
Netherlands
Slovakia
Switzerland
United
States of
America
BAT according to the
BREF
0.05 municipal, hazardous and medical waste incineration, 8 hour average
0.2 waste incineration; common ELV for Hg, Tl, Cd
0.1 waste incineration, 11% O2
0.39 Medical Waste incinerators (11% O2)
0.06 MWCs, existing installations (11% O2)
0.005 to 0.09 Range for 5 types of hazardous waste combustors (11% O2)
0.001-0.02 waste incineration, daily average
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References
CCME 2000
Canada-wide Standards for Mercury Emissions. Canadian Council of Ministers of the Environment, Quebec, June 5-6, 2000
EC 2001
Ambient air pollution by mercury - Position Paper. European Communities, Luxembourg, 2001.
EIPPCB 2005
Integrated Pollution Prevention and Control: Reference Document on the Best Available Techniques for Waste Incineration. European IPPC Bureau, Sevilla: July 2005.
EPA 2000
Draft Report for Mercury Reduction Options. United States Environment Protection Agency,
September 2000.
UNEP 2002
Global Mercury Assessment. United Nations Environmental Programme Chemicals, 2002.
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