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Hydrogen Production from Biomass with
Chemical Looping Gasification Technology
Qinhui Wang
Dr. & Professor State Key Laboratory of Clean Energy Utilization, Zhejiang University
Background Biomass is one of the important energy
resource Renewable;Abundance; Low emissions CO2 neutral, minus CO2 balance with CO2 capture process Low utilization efficiency now (e. g. direction
combustion) High efficiency system will be a developing
trend Biomass for Hydrogen production maybe an
available selection
Hydrogen from biomass
Available hydrogen production way
Realize high utilization efficiency for biomass
Hydrogen production with CO2 capture will be one of the selection for the biomass utilization:
Chemical Looping Gasification Processes with CaO
Main reactions in CFB combustor:
CaCO3=CaO+CO2-178.1kJ/mol
C+O2=CO2+393.791kJ/mol
H2+1/2O2=H2O+286kj/mol
Steam
H2 rich gas
CO2 rich gas
biomass
Char、CaCO3
CaO Fluidized bed Gasifier
Fluidized bed Combustor
O2
Main reactions in gasifier: C+H2O=CO+H2-131.6kJ/mol CH4+H2O=CO+3H2-206.3kJ/mol(reforming reaction) CO+H2O=CO2+H2+41.5kJ/mol (water-gas shift) CaO+CO2=CaCO3+178.1kJ/mol (carbonation reaction) H2S+CaO=CaS+H2O
Chinese patent: ZL20031108667.5,Authorized in Jan. 2006
molCkJHCaCOLOHCCaO /6.02( 232 ++→++ )
Advances: Reduce the requirements on gasification. Only
part of biomass with high activity is gasified and the char with lower activity is burned in CFB combustor.
Realize anaerobic hydrogen production with CO2 acceptor gasification and high concentration CO2 for disposal in combustor
Realize near zero emission: few ammonia (NH3) generating during gasification may be removed easily, H2S is captured by CaO in the gasifier and transformed into CaSO4 in the combustor. Other pollution gas may be disposal together with CO2 gas stream.
Invention Patent of China
Hydrogen from solid fuel with near zero emission by anaerobic gasification. China patent No. ZL 2003 1 0108667.5, Authorization Date: 2006.1.11
“近零排放的固体燃料无氧气化制氢方法”,
专利号:ZL20031108667.5,2006年1月授权
System Analysis and calculation
Thermal Equilibrium Calculation (FactSage 5.2 )
Kinetic simulation
H2
CO
CO2
CaO的作用
Reaction Temperature:800℃; Pressure=2MPa, [H2O]/[C]mole ratio=2
Effect of the mole ratio [Ca]/[C]
Effect of reaction temperature [H2O]/[C]摩尔比为2, [CaO]/[C]摩尔比为1
温度 H2产量 CH4产量/体积分数
温度 >850℃ H2体积分数
Effect of operating pressure
Reaction temperature:850℃,[H2O]/[C]mole ratio=2, [CaO]/[C]mole ratio=1
压力 H2体积分数 CO和CO2产量/体积分数
Effect of [H2O]/C mole ratio
Reaction temperature=800℃,pressure=2MPa, [CaO]/[C]mole ratio=1
[H2O]/[C]摩尔比 H2产量 CH4产量/体积分数
Simulation on a typical condition
Calculation parameters : Gasification temperature: 1023 K Gasification pressure: 1MPa Combustion temperature: 1173 K Combustion pressure: 1MPa Analyses of Sawdust :
Industrial analyses(%,as received) Ultimate analyses(%,as received)
M A FC V C H O N S 2.985 6.795 16.32 73.9 45.13 4.805 39.47 0.605 0.21
Hydrogen yields Gas composition
CO2 concentration in combustor CaCO3 conversion ratio
Experiments on Pressure TGA
TherMax500型加压热天平
最高温度 1100℃
最高压力 10MPa(常温) 7MPa( 1000 ℃ 时)
可控温度区域 50mm
样品容积 35ml
最大样品量 100g
负荷变化范围 +/-10g
灵敏度 1μg
真空度 5×10-4 torr
反应气体 2
最大升温速率 25 ℃/m
主要技术指标:
Material: Rice straw, wood, wheat straw
Proximate analysis Qb,ad
(J/g)
Qb,ad
(Cal/g)
Ultimate analysis
Mad% Aad% Vad% FCad% Cad% Had% Nad% St,ad% Oad%
Rice
straw
14.13 13.47 61.43 10.97 14363 3428 36.29 4.13 1.09 0.18 30.72
wood 14.85 0.45 68.41 16.30 16855 4033 44.81 3.19 0.23 0.04 36.45
Wheat
straw
13.59 6.44 67.58 12.41 15645 3741 38.06 3.98 0.53 0.19 37.23
Experiments on Pressure TGA or TGA
Effect of CaO on biomass pyrolysis in TGA
There exist two distinct mass loss stages with CaO
TG-FTIR measurements First mass lose stage Second mass lose stage
CaO may absorb CO2 in the first stage, and reduce tar yileds
Carbonized CaCO3 will be calcined in the second stage
-20
-15
-10
-5
0
5
0 200 400 600 800
DTG
/%*m
in-1
Temperature t/oC
常压
0.3MPa
0.6MPa
0.9MPa
1.2MPa
-25
-20
-15
-10
-5
0 0 200 400 600 800
DTG
/%*m
in-1
Temperature t/oC
常压
0.3MPa
0.6MPa
0.9MPa
1.2MPa
Effect of pressure on biomass pyrolysis in pressure TGA
A diagram of the pressurized dual fluidized bed system
Pressurized fluidized bed gasification system
Experiments
Proximate analysis [ar, %w] Ultimate analysis [daf, %w]
M A V FC C H N S O(diff.)
8.22 0.28 78.75 12.75 52.22 7.23 0.11 0.10 40.34
Material: Sawdust (0.23-0.38mm) Pressure: 1~4 bar Temperature: 530~760 C CaO: 0.15-0.25mm
Influences of pressure
CaO/C=1,H2O/C=0.89,T=680℃
P H2
(1) Increased reactant concentrations
(2) Enhanced CaO carbonation reaction
CO2 CO
1 2 3 4
0
10
20
30
40
50
60
70
0
10
20
30
40
50
60
�
��
�
Hyd
roge
n yi
eld
(g/k
g-sa
wdu
st)
H2 CH4 CO CO2 C2Hm C3Hn
Gas
con
cent
ratio
n (%
)
Pressure (atm)
Influences of CaO/C (pressurized gasification)
P=4 bar,H2O/C=0.89,T=680℃
CaO/C
H2
More CO2 being absorbed
Enhanced water gas, water gas shift and methane steam reforming reactions
CH4 CO
CO2
&
Syngas with H2 concentration of 67.7% was produced.
0 0.5 1 1.2
0
10
20
30
40
50
60
70
80
-40
-20
0
20
40
60
80
100
Hyd
roge
n yi
eld
(g/k
g-sa
wdu
st)�
�
�
Gas
con
cent
ratio
n (%
)
CaO to carbon mole ratio
H2 CH4 CO CO2 C2Hm C3Hn
�
Influences of H2O/C (pressurized gasification)
P=4 bar,CaO/C=1,T=680℃ H2O/C H2
CO
CO2 concentration keeps very low (<1.5%) under pressurized gasification.
CH4+H2O=CO+3H2
CaHb+aH2O=aCO+(a+b/2)H2
0.72 0.75 0.80 0.89
0
10
20
30
40
50
60
70
0
10
20
30
40
50
60
70
�
�
��
Hyd
roge
n yi
eld
(g/k
g-sa
wdu
st)
H2 CH4 CO CO2 C2Hm C3Hn
Steam to carbon mole ratio
Gas
con
cent
ratio
n (%
)
Influences of Temperature (pressurized gasification)
P=4 bar,CaO/C=1,H2O/C=0.89 T H2
CH4 CaHb CO
CaHb+aH2O=aCO+(a+b/2)H2
CH4+H2O=CO+3H2
CO+H2O=CO2+H2
530 600 680 760
0
10
20
30
40
50
60
70
0
10
20
30
40
50
60
70
80
�
�
�
�
Hyd
roge
n yi
eld
(g/k
g-sa
wdu
st)
H2 CH4 CO CO2 C2Hm C3Hn
Gas
con
cent
ratio
n (%
)
Temperature (oC)
Effect on carbon conversion ratio and gas composition
Cconversion 1 bar : 87.7% 4 bar: 92.2%
组分 H2 CH4 CO CO2 C2H4 C2H6 C3H6 C3H8 总量
1bar 15.0 3.75 7.66 1.71 0.964 0.375 0.321 0.107 29.9
4bar 26.0 5.90 6.33 0.482 1.61 0.697 0.536 0.161 41.7
Gas composition in atmosphere pressure and 4 bar pressure
8
1 100%i i
i
sawdust
m Q
Qη == ×
∑
η 1 bar : 51.9% 4 bar: 78.2%
Conclusions
A new process of Hydrogen Production from Biomass with Chemical Looping Gasification Technology has been constructed
It is a prospective system shown by our primary research works
Thanks for your attention!
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