Air

Gasification of biomass
Lecture no. L3-1
Dr hab. inż. Marek Ściążko
Prof. nadzw.
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Technologies and products of thermo-chemical
biomass conversion
PROCESS
PRODUCT
CONVERSION
MARKET
Heat
Combustion
Heat
Boiler
Gasification
Gas
Turbine
Pyrolysis
Bio-oil
Engine
storage
Power
Chemicals
Fuels
Hydrogen
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Potential Biomass Gasifier
Feedstocks
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Gasifier Classification
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BIOMASS GASIFICATION TECHNOLOGIES
Biomass
Biomass
gas
Gas
Pyrolysis
C + CO2 = 2CO
C + H2O = CO + H2
C + O2 = CO2
4H + O2 = 2H2O
Pyrolysis
C + O2 = CO2
4H + O2 = 2H2O
Gasification
Combustion
C + CO2 = 2CO
C + H2O = CO + H2
Air
Air
Combustion
Gasification
Ash
Ash
COUNTER CURRENT/
UPDRAFT
CO-CURRENT/
DOWNDRAFT
Cyclone
Cyclone
Cyclone
Gas
Ash
Biomass
Ash
Biomass
Air
Steam
Air
Steam
Ash
BUBBLING FLUIDISED BED (BFB)
CIRCULATING FLUIDISED BED (CFB)
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Fixed bed biomass gasiefiers
Biomass
Gas
BIOMASA
Drying
Pyrolysis
Gasification
Combustion
BIOMASA
Biomass
GAZ
SUSZENIE
SUSZENIE
PIROLIZA
PIROLIZA
ZGAZOWANIE
UTLENIANIE
POWIETRZE
Air
UTLENIANIE
POPIÓŁ
Ash
POWIETRZE
Air
A)
ZGAZOWANIE
POPIÓŁ
Ash
Drying
Pyrolysis
Combustion
Gasification
GAZ
Gas
B)
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Fluid bed reactors features
Biomass
Process gas
Ideal radial gas mixing
Oxygen (Air)
Steam
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Ideal radial and
axial gas mixing
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Gasification steps
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Gasification reactions
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Evaluation of reactors’
characteristics
PARAMETERS
Reaction temperature [C]
Gas temperature [C]
Throughput [t/h]
Electric power [MWe]
Up-draft
1000
250
10
1 - 10
Tars content
Particulates
v. high
av. high
Mixing intensity
Limits for particle size
Moisture content
Fuel flexibility
low
some
any
no effect
Scaling up
Process control
limited
medium
Conversion efficiency
Thermal efficiency
v. good
v. good
FIXED BED
FLUID BED
Down-draft
Cross flow
Bubbling
Circulating
1000
900
850
850
800
900
800
850
0.5
1
10
50
0.1 - 5
0.1 - 2
1 - 20
2 - 100
GAS CHARACTERISTIC
v. low
v. high
medium
low
medium
high
v. high
v. high
FEEDSTOCK REQUIRAMENTS
low
low
good
v. good
some
some
specific
specific
limited
limited
limited
limited
low effect
low effect
strong
strong
DEVELOPMENT POTENTIAL
low
low
good
v. good
medium
low
v. good
v. good
EFFECTIVITY
v. good
low
good
v. good
v. good
good
good
v. good
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Syngas Contaminants
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GASIFIER CHARACTERISTICS
Parameter
Fuel
-moisture content (%)
-ash content (%, daf)
-size (mm)
Gas
-
temperature (oC)
LHV (kJ/mn3)
tar content (g/ mn3)
particulates
(g/
3
mn )
composition
(%
v/v.)
H2
CO
CO2
CH4
Max commercial capacity
(forecast) (MWth)
Scale-up ability
•
•
•
•
Downdraft
Updraft
CFB
< 25
<6
20-100
< 60
<25
5-100
800
4-6
0,01-6
0,1-8
200-400
4-6
10-150
0,1-3
850
5-6,5
2-30
8-100
15-21
10-22
11-13
1-5
10-14
15-20
8-10
2-3
15-22
13-15
13-15
2-4
1
10
100
poor
good
v. good
< 25
<25
<20
P.Quaak, H.Knoef, H.Stassen, ENERGY FROM BIOMASS, A Review of Combustion and Gasification Technologies; World Bank
Technical Paper No. 422, Energy Series, 1999
H.E.M. Stassen, H.A.M. Knoef, SMALL SCALE GASIFICATION SYSTEMS, Biomass Technology Group BV, The Netherlands
P. Hasler*, Th. Nussbaumer, GAS CLEANING FOR IC ENGINE APPLICATIONS FROM FIXED BED BIOMASS GASIFICATION,
Biomass and Bioenergy 16 (1999) 385±395
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A.V. Bridgwater, Fuel 1995, 74 (5), 631.
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Composition of biomass derived
syngas
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Pilot scale tests
EKOD gasification reactor - construction and process description
1 – gas generator
2 - lock
3 – transport and feeding system
4 – ash removing system
5 – gas pipeline
6 – air installations
7 - burner
Technology:
Power:
Fuel:
granulation:
fixed bed, updraft reactor
2,5-3,5 MWt
Waste Biomass
> 300 mm
Gasification agent: Air
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Pilot scale tests
Stand for gasification tests
Fuel
(biomass)
Air
3
T
3
P
3
V
3
A
pressure
temperature
flow
composition
6
T
Gas
Boiler
Air
separator
1
A
Gasifier
1
V
PTVA-
6
P
3
V
3
A
combustion
gases
5
V
2
T
2
P
2
V
4
T
4
P
4
V
Ash
Dust
Ash
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Pilot scale tests
Fuel characteristics
Feedstock
Form of
the fuel
LHV,
MJ/kg
Volatile
matter
% w/w,
Ash
% w/w
Ultimate analysis,
% w/w.
Moisture
% w/w
C
H
O
N
Waste wood
Irregular
fuel
pieces up
to 30 cm
17,6
79,6
0,4
7,5
48,7
5,9
37,4
0,1
Wood chips
Wood
chips 3-5
cm
16,1
71,9
0,4
15
44,1
5,2
35,3
0,05
Fiber and chipboard
Irregular
fuel
pieces up
to 30 cm
15,6
69,0
0,5
15
42,9
5
35,8
0,8
Tyres / wood mixture
Irregular
fuel
pieces up
to 30 cm
25,6
68,2
2,7
8
63,1
4,8
20,5
0,1
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Pilot scale tests
Results: gasification reactor
t,
Fuel flow
rate
Air/fuel
ratio
Gas flow
rate (dry)
Gas LHV
(dry)
Cold gas
efficiency
oC
kg/h
kg/kg
mn3/kgfuel
kJ/mn3
%
Waste wood
760
490
2,1
2,5
5660
80
Wood chips
685
580
1,9
2,3
5200
75
Fiber and chipboard
685
680
1,8
2,2
4770
68
Tyres / wood mixture
690
360
2,1
2,4
9250
86
Feedstock
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Gas composition
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Pilot scale tests
Results: gasification reactor- boiler
Feedstock
pollutant
Emission
Standard
Waste wood
Wood
chips
Fiber and
chipboard
Tyres / wood
mixture
76
341
338
50
-
Bellow
detection
level
39
173
293
400
NO2, mg/mn3
209
212
625
341,3
400
Pył, mg/mn3
54
58
230
284
100
CO, mg/mn3
SO2, mg/mn
3
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Pilot scale tests
Results: comparison with literature
25
150
co-current
counter current
20
Ecod
Ecod (biomass)
15
10
5
0
LHV
(MJ/Nm3)
Tar (g/Nm3)
particulates
(g/Nm3)
H2 (% vol.)
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CO (% vol.)
CO2 (% vol.)
CH4 (% vol.)
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Simulation of the process
60
60
A)
B)
50
50
H2
30
CO2
O2
20
%obj
CO
H2
40
CH4
CH4
CO
30
CO2
O2
20
N2
N2
H2O
10
10
0
 Free Gibbs enthalpy minimization.
 Composition of generated gas:
CO, CO2, O2, H2, CH4, H20, N2.
 Temperature of the process: 750oC
 Feedstock properties: waste wood
0
1,0
1,5
2,0
2,5
0,5
Vp/m pal [m n3/kg]
1,0
1,5
2,0
2,5
Vp/m pal [m n3/kg]
Chemcad software (Chemstations Inc.)
80
6000
70
calculation
experiment
LHV, calculation
LHV, experiments
60
50
59,3
4712
4700
53,8
4000
40
3000
30
20
10
5000
7,4
2000
18,5 18,9
16,2
8,4 8,6
3,2 4,4
LHV, kJ/m3
0,5
% vol
%obj.
40
1000
0
0
H2
CH4
CO
CO2
N2+O2
LHV
compound
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Start up: 2005
WOOG CHIPS GASIFICATION – 5 MWth
Raw wood
Wood chips
Wood
cutter
PELLETS
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Wood chips gasification
Current state

Furniture production plant Holzwerk,
Drygały Poland (waste wood)

Lubuski Tannery Plant, Leszno Górne,
Poland (tanning wastes)

Enpal (Słubice, Poland) – wood chips
 ICPC, ZAMER, Modern Technologies
and Filtration
 drying installation of wood waste for the
pellets production
Parameter
Gasification agent
Thermal output
Gas temperature
Fuel (wood chips)
 Water kontent
 LHV
 granulation
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Unit
value
-
air
MWth
3-5
oC
<800
%
GJ/Mg
mm
< 20
> 14
6-40
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Process
gas
Air
Fuel:
Wood chips
Gasifier
Moisture content:
20%
LHV:
14 GJ/Mg
Combustion
chamber
Flue
gas
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Capacity:
1500 kg/godz
Wood
chips
THERMAL CAPACITY
5 MWt
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Process instrumentation and
control template
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Visualization of gasifier
performance
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Gas combustion chamber
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Coal – biomass co-firing systems
Indirect co-firing
B)
A)
BOILER
flue gases
biomass
 High flexibility in arranging and integrating
the main components into existing plants
BOILER
BIOMASS
 Now pretreatment of biomass is needed –
low gas quality is sufficient for co-firing
COMBUSTION
CHAMBER
 Gas could be fed to the boiler without
cooling and cleaning
D)
C)
BOILER
gas
biomass
BIOMASS
PULVERIZER
GASIFICATION REACTOR
BOILER
 No slag formation in the boiler (most
important issue in case of direct co-firing)
 Favorable effects on power plant
emissions (CO2 - biomass, NOx reburning effect)
 No severe modifications of the existing
coal fired boiler
•
•
•
•
T. Nussbaumer, Combustion and co-combustion of biomass, “12th Conference and Technology Exhibition on Biomass for Energy, Industry and
Climate Protection”, Amsterdam, 2002.
G. Moritz, J. Tauschitz, Mitverbrennung von Biomasse in Kohlekraftwerken. Conference „Bois-Energie, Mulhouse, France, 2001
Energetische Nutzung biogener (Ersatz-)Brennstoffe durch Vergasung und emissionsoptimierte Einspeisung mittels Gasfeuerung in (Dampf-)
Kesselanlagen und Ofenprozessen. Konzeptpapier, Fraunhofer-Institut für Umwelt-, Sicherheits- und Energietechnik UMSICHT, November 2002.
A. Mory, J. Tauschitz, Holz Energie 1999, 4, 37.
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Future development
Small scale CHP systems
• Tars

• Particulates
biomass

• Alkali
metals

• Sulfur, chlorine
Gasification
Contami
nant
Examples
Particula
Ash
tes
Tars
Refractory
aromatics
Gas cleaning
Power and heat production
Problems
Erosion,
emission
Clog filters,
deposit
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internally,
Cleanup method
Filtration,
scrubbing
Tar cracking, tar
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removal
Gas quality required
IMURITIES CONTENT [g/m3]
Ash
Nitrogen (NH3+HCN)
Sulphur (H2S+COS)
Alkalis
Chlorine (HCl)
Tars
Heavy metals
1.33
0.47
0.01
0.1
0.1
0.15
0
REQUIRAMENTS
GAS QUALITY REQU.
LHV [MJ/m3]
Particulates [mg/m3]
Tars [mg/m3]
Alkali metals [ppm]
BOILER ENGINE
GT
X
>4
>4
X
5 - 50
5-7
X
< 0.5
<0.1
X
1-2
0.2 - 1
Max concentration
of CO for FC – 100 ppm
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Gas treatment methods
EXTERNAL
THERMAL
CRACKING
INTERNAL
THERMAL
CRACKING
ULTRA-HIGH TEMPERATURE
GASIFICATION
Biomass
Process gas
Oxygen (Air)
Steam
EXTERNAL
CATALYTIC
CRACKING
INTERNAL
CATALYTIC
CRACKING
CAT
PHYSICAL TAR
SEPARATION
QUE
CAT
Waste water
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Technology options dilemma
-scale effect
ELECTRICAL
POWER
1 MM t/a
TECHNOLOGY OPTIONS
700 MM $
METHANOL
Plant capacity
H2
SNG
MOTOR FUELS
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6 MM t/a
2000 MM $
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Indirect biomass gasification –
prospect for efficient hydrogen
production
Oxygen
Tlen
Acronym:
PYROSYN
Char +SHC
SOLID HEAT
CARRIER
SEPARATION
Biomss
DRYING
PYROLYSIS
SHC+CFBR
CONVERSION
GAS CLEANING
Heat carrier
Process gas
Heat
FLUID BED
COMBUSTION
BLOCK DIAGRAM - BIOMASS
PYROLYSIS WITH SOLID HEAT
CARRIER FOR SYNTHESIS GAS
Air
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Summary

EKOD fixed bed gasifier is characterized by relatively high conversion
efficiency. Depending on used feedstock, the efficiency was in range
68-86 % (cold gas efficiency).

Produced gas was characterized by relatively high calorific value
(4800 – 9200 kJ/mn3) and low tar content (400 – 3000 mg/mn3).

Operation experiences confirm the flexibility and reliability of the
construction and readiness for commercial applications particularly
for heat generation in stand alone boilers or in existing co-fired units.

Possible further development direction comprises small scale CHP. It
needs to develop tars free gasification systems. This option gives the
opportunity for broad application in heat and power generation
industry.

Biomass gasification and related syngas production for chemical
synthesis or hydrogen production still needs new technology options.
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