Biowaste to power plants at high
portions ”Biosafe” TEKES 40181/06
F uels
T2
T1
P ilo t- sc ale
ex p erim en ts
w ith a B F B re a cto r:
p ro tective re a ctio n s
VTT
F u el selectio n ,
D eta iled a n a lysis
Å A U , V T T (J )
H arm ful a nd
pr ote c tive
c om p ou nd s
T3
F u rn a ce
sam pling
(N a , K C l,
UKU
T e st op tim isation
T5
T o valid ation
K loor in
K err ostum inen,
likaa ntu m in e n
M ix ing o f ad d itive
in a fu rn a c e
U T sin g hu an
L iu otetut
S uoja
aine et
T4
R eliable sam pling
of risk y com p oun ds
D ep o sition m od el
(Å A U )
E ffective u tilisatio n o f b io w a ste
In en ergy p rodu ction
Martti Aho, VTT, Liekki IV Day 23.1.2008
Biosafe/ members of the leading group
TEKES/TE-keskus
VTT prosessit
Åbo Akademi
Kuopion yliopisto
Kvaerner Power
Kemira OYJ
Lassila & Tikanoja
Helsingin vesi
*Climbus-ohjelman
Henkilö
Asema
Puh.
Mauri Marjaniemi
teknologia010 521 5224
Jatta Jussila*
asiantuntija
Martti Aho**
johtava tutkija
040 558 6945
Var. Pasi Vainikka
tiimin vetäjä
014 672 514
Mikko Hupa
professori
02 215 31
Var. Patrik Yrjas
TkT
02 215 31
Jorma Jokiniemi:
professori
040 5050 668
Var. Olli Sippula
DI
Jaani Silvennoinen
Tutkija
020 14 121
Jari Kukkonen
Tutkija Oulun yks.
010 862 5611
Lassi Hietanen
Tuotepäälllikkö
010 636 5412
Yrjö Lundstöm
Ympäristöpäällikkö
09 4734 3425
koordinaattori, jakelulistalla ** Projektiyhteenliittymän kokoonkutsuja
Background
CASE 1. BARK/FOREST RESIDUE
Heat transfer
surface
COMPOUN
D
ALKALI
CHLORIDES
S
RI
Y
SK
Cl releases
ä corrosion
Lack of
protecting
compounds
Low ash
content
BARK/FOREST RESIDUE
Risk description:
Cl deposition
which
can lead
to high
temperature
superheater
corrosion
Fouling of superheater tubes
Superheater tubes damaged by high
temperature chlorine corrosion
Optional ways to problem solution
R
SILICATES,
SULPHATES
Y COMPOUN
ALKALI
CHLORIDES
S
ISK
ING REACT
ECT
IO
T
O
ALKALI
FOREST RESIDUE
NS
PR
CASE 2. PROTECTING POWER OF COAL
PROTECTIVES
SULPHUR DIOXIDE,
Al-SILICATES
COAL
Co-combustion
Problem solution by
co-firing means:
Coal contains sulphur
and aluminium silicates:
Alkali chloride destruction
Possible by
a) Sulphation SO3 + 2 KCl+
H2O -> K2SO4 + 2 HCl Note:
sulphur in SO3 form!
b) Alkali aluminium silicate
formation:
Al2O3*2SiO2 + 2KCl +H2O ->
M2*Al2SiO3*2SiO2 + 2 HCl
Note: Sulphation may need high S
mass flow to be effective increasing
SO2 emissions
New and patented: Effective alkali chloride destruction
by additives forming SO3 at critical furnace zones
2MCl + SO3 + H2O -> M2SO4 + 2 HCl
Na2SO4
K2SO4
HCl
SO3 attach
NaCl, KCl
Very effective S => small dosages,
no increase of SO2 emissions
This project
•Utilisation of effective sulphur present
in different sludges to alkali chlorides
destruction in the boiler furnace
•Destruction of alkali chlorides with
minimum sludge portions and SO2 slip
•No bed agglomeration allowed
•Toxic emissions must controlled
•Note: Emissions limits are determined
by the co-incineration directive
Plant idea
• Dried and pelletised sludge is transported from
selected sources to a particular power plant
equipped with a bag filter and chemicals to clean
the flue gases
• The plant has high efficiency (with high steam
values , > 500 C steam)
• The main fuel can be for example forest-based
biomass and also include biomass components
classified to waste (demolition wood,
impregnated wood)
Workprogramme briefly
Goals
• Main goal: Basis to utilise demanding biowaste in
energy production in effective power plants will
strengthen
• Sub goals (serving power plant availability):
(a) Improved furnace probing tools for risky compounds
(b) Improved control of formation and destruction of risky
furnace compounds
(c) Utilisation of the protective compounds in sludges
Tasks and time schedule
Tasks
Fuels
T2
T1
Pilot- scale
experiments
with a BFB reactor:
protective reactions
VTT
Fuel selection,
Detailed analysis
ÅAU, VTT (J)
Harmful and
protective
compounds
T3
Furnace
sampling
(Na, K Cl,
UKU
Test optimisation
T5
To validation
Kloorin
Kerrostuminen,
likaantuminen
Mixing of additive
in a furnace
U Tsinghuan
Liuotetut
Suoja
aineet
T4
Reliable sampling
of risky compounds
Deposition model
(ÅAU)
Effective utilisation of biowaste
In energy production
Time schedule 1.8.2006->
02
T1
T2
T3
T4
T5
04
x
x
x
x
06
x
x
x
x
08
x
x
x
x
10
x
x
x
12
x
x
x
x
14
16
18
20
22
24
26
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
28
x
Task 1 Fuels
•Risky fuels as sources of KCl and NaCl
Bark, bark/recycled fuel (REF)
Protective sludge with effective sulphur
• 2MCl + SO2 + ½ O2 + H2O -> M2SO4 + 2 HCl
where M is K or Na
Power of fractionation analysis: instead of element
contents it gives information of the reactivity of the
elements
REF to be used
Biosafe REF
ppmW
By Åbo Akademi
20000.00
18000.00
16000.00
14000.00
12000.00
10000.00
8000.00
6000.00
4000.00
2000.00
0.00
Rest
HCl
Acetate
Water
Untreated
Si
Al
Fe
Ti
Mn
Ca
Mg
P
Na
K
S
Cl
To stack
Task2: Reactor 20 kW
BFB pilot plant
Observation
port
Gas cooling
Sampling
port
Deposit
probe
Temperature
control
Gas
sample
Gas probe
Sampling
port
Bag
filter
Heating zone 4
Sampling
port
Obervation port/
Deposit probe
Cyclone
Heating zone 3
Tertiary air optional
Tertiary air optional
Obervation port
Tertiary air (preheated)
Heating zone 2/
Cooling zone 2
Fuel container 2
Fuel container 1
Additive
container
Obervation port
Heating zone 1/
Cooling zone 1
Obervation port
BED
made of quarz
Secondary air
(preheated)
Primary gas heating
PC control and data logging system
Nitrogen
Air
Tasks 2, 3 related to probing of Cl, S, Na and K compounds
dib. air
Ejektor
ELPI
Cyclone
T 800-1000°C
VTT diluter
Ejektor
Cyclone
MFC
Cooling system
DLPI
Exh
nitrogen
Ftir & CO2
Task 2 Deposit probing to analysis
Further illustration:
To: Åbo
Akademi
30mm
16mm
Results from first tests
Cl concentrations at critical positions of the deposit:
base fuel: spruce bark
8
Bark alone
p-% Cl kerrostumassa
7
Tmetal 500 C
Tflue gas. 650 C
6
5
4
3
2
Tmetal 500 C
Tflue gas 850 C
2 % enb sludge 1 mixed to bark
1
0
Kuori FB Kuori FB Kuori FB Kuori
Kuori
Kuori 2% VKM 2% VKM 2% VKM 2% VKM 2% VKM 2% VKM
tulo
sivu
jättö
VK tulo VK sivu VK jättö FB tulo FB sivu FB jättö VK tulo VK sivu VK jättö
Cl concentrations in the fine fly ash with different sludges and dosages
Klooripitoisuudet välikanavanäytteissä eri polttoaineilla
6
4.02 - 10 µm
1.61 - 4.02 µm
0.64 - 1.61 µm
0.26 - 0.64 µm
0.1 - 0.26 µm
0.03 - 0.1 µm
<0.03 µm
5
mg/Nm3
4
3
!
2
!
1
0
Kuori
Bark alone
2%VKM
4%VKM
6% VKM
8%VKM
4%KEMC
Conclusion:
• Even a small portion of sludge mixed to bark
destroyed the alkali chlorides in the furnace
and prevented Cl deposition to the
superheaters during bark combustion
• Next stage: More demanding startpoint will
be used: 10% enb. REF will be mixed to bark
• Old aspect: Sludges make only harm to the
boilers by increasing emissions etc.
• New aspects: Sludges can protect boiler
furnaces!