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

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-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

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�

��

�

Hyd

roge

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(g/k

g-sa

wdu

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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

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Hyd

roge

n yi

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(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

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�

�

��

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

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�

�

�

�

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!