Energy Efficiency in IPPC installations,
21.-22. October 2004 in Vienna
Austria Trend Parkhotel Schönbrunn
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Innovative examples of energy efficiency
in the German sugar industry
- dewatering and drying process for
sugar beet pulp Dipl.-Ing. Christian Voß
Südzucker AG for the German
Association of Sugar Industry
Dr.- Ing. Joachim Wieting
U MWELT
B UNDES
A MT, Berlin
Werk Warburg, D-34414 Warburg
Tel. 05641/ 9413
Postfach 33 00 22, D-14191 Berlin
Tel. 030/ 8903-2829
Christian.Voss@Suedzucker.de
joachim.wieting@uba.de
Structure
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1. Introduction (targets and development of the
specific energy requirement)
2. Mechanical dewatering process for sugar beet
pulps in the sugar industry as regards energy
3. Drying processes (drum drying, low temperature
drying and evaporation drying)
4. Energy aspects of pulp drying
5. Comparison of energy consumption and the
economics of different types of installations with
examples
6. Characterisation of the technology –
economic and ecological aspects
Background and Motivation
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With the finalisation of the Council Directive 96/61/EC concerning
„Integrated pollution prevention and control“, the so-called
„IPPC Directive“, the concept of an integrated approach to reduce
environmental pollution is being pursued at European Community
level for the first time, with all installations covered by the directive
now requiring permits.
The EU Commission is supporting the
implementation of the directive as part of
its exchange of information by having
leaflets compiled on the „best available
techniques (BAT)“ by the European
Integrated Pollution Prevention and
Control (IPPC) Bureau in Sevilla,
Spain.
Background and Motivation
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• The „food, drink and milk“ BREF gives information at community
level on the best available techniques in the sugar industry to help
promote the use of these techniques and to support the member
countries effectively in their efforts to protect the environment.
• The efficient use of energy in the industry
helps avoid and/or control emissions in the
air, in water and in the ground as far as
possible.
•The formulation of the directive into a new
VDI guideline in Germany will set out
primary and secondary control measures
and new reduced emission figures for
production technology.
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Introduction
precautions in the interest of the climate
Agreement between German sugar industry and the
government board signed on 19.12.2000:
 Reduction of the specific CO2 emissions of 41 – 45 %
by 2005/06
Base year 1990: CO2 emissions/beet
Target year 2005/06:
148 kg/t
81 – 87 kg/t
achieved 2000/01:
84 kg/t
with 288.5 kWh/ton of beet
Target achievement:
almost 100 %
Introduction
Specific energy consumption in the
German sugar industry
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125
kWh /
100 kg beets
100
75
50
25
current 1996:
30,6
ABL
DDR / NBL
basis 1990:
35,6
D, ges
target 2005 :
29
0
1950
1960
1970
1980
year
ABL = old Federal states
NBL = new Federal states
D
= Germany as a whole
1990
2000
2010
Introduction
Specific energy consumption in the
German sugar industry
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Since 1990 > 300 Million € have been invested in projects for
combined heat and power generation (CHP).
Degree of efficiency of heat and power combinations > 90 %
re-use of the heat several times normalf = 7 – 8
Future: physical limits
increasing technical expenditure (costs)
marginal energy savings
______________________________________________________
Personal remarks on sugar market regulation
Introduction
Energy conversion in a beet sugar factory
and VDI extra edition 2594

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Main flows of energy and technical processes are more
closely interlinked than in any other sector of industry.
 Amount of energy used
Sugar production : Dried pulp production
2
:
1
 VDI-Guideline 2594
„Emission reduction in pulp drying plants
in the sugar industry“, First printed August 2004
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Energy aspects
of the dewatering process for beet cossettes
Production of dried pulp with 90 % dry substance and
10 % water from extracted cossettes with 10 (- 14) % dry
substance and 90 % water
in 2 dewatering stages:
mechanical thermal
Amount of energy used
kWh/t water
approx. 30 approx. 3.000
1
Target:
:
100
To remove as much water as possible mechanically.
Energy aspects
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of the dewatering process for beet cossettes
State of the art:
Spindle presses horizontal/vertical
pulp inlet
screen
ring, axially relocatable
for pressing pressure
variation
press water
collector
pulp outlet
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Energy aspects
of dewatering process for beet cossettes
34
3,4
32
3,2
30
3
28
2,8
26
2,6
24
2,4
22
2,2
20
2
Water carrying in kg Water/
kg Dry-substance content
Dry-substance content in
Press-pulps in %
Quantity of material pressed out depends on capacity of presses Hardening with calcium ions (gypsum), Development by Südzucker (SZ):
Campaign
Dry-substance content in %
Watercarying in kg Water/kg Dry-substance content
SZ-Pressing target before drying: 32.5 % dry substance in the pressed pulp
Energy aspects
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of dewatering process for beet cossettes
Other mechanical dewatering processes % dry substance in the pressed pulp
• Diffusive dewatering:
65
in combination with evaporation plant to concentrate the press water
Disadvantage:  no suitable separation of solids/liquids
• High-pressure, multi-layer pressing:
50
Filter band press: 300 bar; 15 min. pressing time
Disadvantage:  no suitable filter cloth quality
no reliable control of the 300 hydraulic
control loops
• Extraction under alkaline conditions
Pilot installations in France, Germany and England
45 – 50
Energy aspects
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of dewatering process for beet cossettes
Combination of electroporation and alkaline extraction
• Alkaline extraction results in increased deposits of calcium ions
and thus to a definite increase in the pressability of the extracted
cossettes
- Dry substance (DS) content of extracted cossettes : 40 - 45 % (an increase
of approx. 10 % DS)
• Opening the cells by electroporation to prepare for deposit of
calcium ions
- opening the cell membranes by high voltage impulses
• high voltage impulses: a voltage of several
hundred kV for the duration of approx. 1 µsec
• low energy demand: approx. 1 kWh/t beet
Energy aspects
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of dewatering process for beet cossettes
Changes in the mechanical properties of beet due to electroporation
• Electroporation increases the flexibility of the cossettes considerably and
enables them to stand up to heavier mechanical stress.
Energy aspects
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of dewatering process for beet cossettes
Possible configuration of electroporation and extraction*
electroporation
electroporated
beets
electroporated and
alkalined cossettes
slicing machine
lime
mash
*patent
applied for
juice towards juice purification
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Drying process
Start-up line 1,5 bar
85 bar
DU 2
VD 2-7
Heating oil
Generator
Generator
Steam turbine
85 25
25 3
3 bar
3 bar
4,5 MW
Gas turbine
Boiler
14,7 MW
25 bar
VD 1
3,3 bar
VT 1
VT 2
DU 1
DU 3
Steam system of a sugar factory with steam
drying
Drying process
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Legend:
1
Cossette feed screw in cell 1
2
Stationary guide vanes
3
Cylinder with cyclone effect
4
Cyclone over cell 16 for separating entrained cossettes
5
Steam inlet into cyclone
6
Stationary guide vanes for steam return
7
Superheater for secondary steam
8
Blower fan for creating fluidised bed
9
Generated steam exit
10
Feed screw for cossette output from cell 16
Steam system of a sugar factory with
steam drying
Energy aspects
of cossettes drying
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In order to consider the energy aspects of the
installations described, the general data of the
factories with both direct and indirect dewatering
systems have been standardised as follows:
 Beet processing 10.000 tons/day
. Length of „campaign“ (season) 90 days p.a.
 Mass flow of pressed pulp: 160 kg/t beet processed
= 66,7 tons/h
 Dry substance content of the pressed pulp 31 %
 Dry substance content of the dried pulp 90 %
 Steam consumption of a sugar factory for 200 kg/t processed
beet = 83.4 t/h
 Live steam pressure 85 bar
 Live steam temperature 525 °C
 Thermal value of the fuel 40.195 kJ/kg
Energy aspects
of cossettes drying
 Electrical energy demand of the sugar factory without
drying 10.4 MW = 24.96 kWh/t beet processed
 Complete crystallisation of the thick juice in the beet
campaign
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These
norms pre-suppose that the factories have the
.
following technical installations:
 A steam generator with 85 bar and 525 °C.
 A corresponding back pressure turbine
3 bar back pressure to supply the evaporation station
or 3 bar back pressure and 25 bar extraction pressure
to supply the steam dryer.
 A gas turbine to reduce the use of electric energy when
using a steam dryer.
effluent treatment plant which can process the
condensed vapours from the evaporation dryer.
Summary of the examples of
installations
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Steam High
Low/high
Factory
dryer temperature temperature without
dryer
dryer
a dryer
Total electric
energy demand
MW 11.55 11.20
12.10
10.40
Total fuel energy
MW 73.72 111.83
104.80
67.13
Total electric
energy obtained
MW 11.48 11.66
11.66
11.66
Total energy costs €/h
1,182 1,780
1,695
1,048
Total energy costs 103
per campaign
€/a
2,532 3,845
3,661
2,264
Summary of the examples of
installations
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Additional energy costs in comparison to a factory
without dryers for the individual variations:
• High temperature dryers
• Low/high temperature dryers
• Steam dryers
1.581 103 €
1.397 103 €
268 103 €
Operation related costs (higher investment costs of installations
in comparison to lower fuel costs in operation)
• High temperature dryers
• Low/high temperature dryers
• Steam dryers
388 103 € p.a.
460 103 € p.a.
554 103 € p.a.
Summary of the examples of
installations
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Investment costs plus net running costs of the dryer
for the individual variations:
• High temperature dryers
• Low/high temperature dryers
38.4 Mio. €
40.7 Mio. €
• Steam dryer
40.9 Mio. €
Characterisation of the technology:
At the present time steam drying is the best available technique
for new sugar factory construction or for complete
reconstruction of energy production and heat control systems.
However, it cannot be integrated easily into a normal existing
factory.
Advantages achieved by
steam drying
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Main achievement - Improvements for the
environment with regard to emissions and energy
consumption:
• Emissions are avoided by direct primary use of energy for
drying.
• No application of steam-volatile and odorous vapours.
• Energy consumption 30% less than in a factory with direct
drying.
Inter-media effects
• Transfer of the exhaust fumes into the effluent (approx. 1.200 m3
effluent with a chemical oxygen requirement of 1.500 mg/l and a NH4content of 25 mg/l).
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THANK YOU
In conclusion we should like to thank all those who
participated the members of the VDI working group 2594,
the participating companies in the Sugar Association
and all of you for your attention.
THANK YOU