Experimental Study of Syngas Generated

from Biomass Pellet in an Interconnected

Fluidized-bed Gasifier

6 June 2018

Session 22: Pilot-plants & operations (2)

10:00 – 10:20

Presenter: Yau-Pin Chyou, Ph. D.

Institute of Nuclear Energy Research (INER)

Co-Authors: Wei-Chun Chang, Yin-Ching Tung,

Po-Chuang Chen, Rei-Yu Chein,

Kung-Tung Wu*

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Outlines

Introduction INER’s Mission

Motivation: Indirect Gasification

Interconnected Fluidized-Bed (IFB) Concept of IFB

History of IFB Development

Experimental System Configuration

Feedstock

Testing Parameters

Results Bed Temperature in the Gasification zone

Gas Velocity

Bed Temperature in the Combustion zone

Tar Content

Summary and Future Work Source: http://maps.google.com/,

http://www.tia.org.tw/report/PS0931206.htm 1

Institute of Nuclear Energy Research

History: founded since 1968 and currently under the administration of Atomic Energy Council (AEC).

Mission: the sole national research institute, dedicated to energy technologies R&D and promotion for peaceful applications of nuclear science in Taiwan.

Location: in Longtan District, Taoyuan City, ~30 miles SW away from Taipei City (about 1 hour drive), in scenic and historic suburban surroundings close to the Shihmen Reservoir.

Taiwan

Longtan

Source: http://www.tia.org.tw/report/PS0931206.htm ， http://www.dashi.gov.tw/travel.htm ， http://www.wranb.gov.tw/public/Attachment/012910263059.jpg， http://maps.google.com/2

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Institute of Nuclear Energy Research (2)

Research Fields– Radiation Application Technology

– Nuclear Safety Technology

– Environmental and Energy TechnologyPlasma Engineering

Fuel Cell (SOFC, DMFC), Flow Battery

Biomass-energy (Bio-, Thermo-chemical)

Renewable Energy (Wind, Solar), w. Micro-Grid

Clean Carbon as Sustainable Energy (CaSE) System design & optimization

Advanced process development

Carbon capture & reutilization

Solar Photovoltaics

Wind PowerCellulosic Alcohol

Process

Attrition System Temperature Sorption AnalyzerThermogravity Analyzer

CO2 Capture ReactorLaboratory

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Gasifier Type versus Capacity

Basu, P., 2011, Biomass Gasification and Pyrolysis, Burlington, MA, USA , Elesiver.

Fluidized Bed Entrained-flowFixed/Moving Bed

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Gasification

• Gasification Process Introduction– Gasification is a process that converts carbonaceous solid fuel, such as coal,

biomass, waste, etc., into gaseous fuel which is called synthesis gas or syngas.

– The main components of the syngas are CO, H2, CO2, H2O and pollutants.

– The chemical reactions in the gasification technology consist of three processes:

pyrolysis, combustion and gasification.

Ash

Carbon

Hydrogen

Nitrogen

Sulfur

Mercury

Water

Coal Gasification

CO

H2

CO2

H2O

COS

H2S

CH4

Hg

…Syngas

Watanabe H., 2006, Numerical simulation of coal gasification in entrained flow coal gasifier5

Indirect Gasification (1/2)

Motivation: to produce nearly Nitrogen-free syngas from biomass

Indirect gasification in small- and medium-scale plants (<100 MWth).

Typical bioSNG efficiency ~60-70%.

Gasification Combustion

Biomass/Waste

Steam Air

Heat

Char

Raw syngas, CO, H2, CO2, CH4… Flue gas

Gas cleaning

Methanation

BioSNG

CO2

removal

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Indirect Gasification (2/2)

• Features: nearly Nitrogen-free syngas

7100kWth Cold Model

Hot Model

under commissioning

Dual Fluidized-Bed (coop. with TU Wien) Interconnected

Fluidized-Bed

(coop. with NCHU)

Vlek (1997)

Test data

Concept of IFB

• Combining Dual Fluidized Beds into One Unit

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Interconnected Fluidized-Bed (IFB)

Vlek (1997)

Advantages•Higher solid circulating rates

•Less particle attrition

•No transport pipes

•Easy construction

Hasegawa et al. (1980)

1 3

2

4

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20141995

History of IFB Development (1/2)

Kunii (1980) proposed a

concept design firstly combined

gasification with combustion

processes

Delft University of Technology (DUT)

(1990’s) realized the concept to develop

IFBs, such as the regenerative

desulfurization process

Kunii (1980)Snip et al. (1995)

Korea Institute of Energy Research (KIER)

(2014) studied gas mixing behaviors in a

multiple IFB (partitioned fluidized bed) cold

model

1980

History of IFB Development (2/2)

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2014~

Commissioning of a 200 kWth

IFB gasifier (fuel: RDF)

Hydrodynamic study of IFB applied to

the concepts of chemical looping

processes and gasification (cold model )

Experimental Study of Syngas Generated

from Biomass Pellet in a 20 kWth hot model

(This study)

2004

Taiwan

200 kWth IFB gasifier

Photo: Wu et al. (2004)

Industrial Technology

Research Institute (ITRI)

INER and National Chung Hsing University (NCHU)

System Configuration

• 20 kWth IFB Gasification System

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1 Gas inlet

2 Preheater

3 Windbox

4 IFB

5 Feeder

6 Cyclone

7 Ash tank

8 Scrubber

9 ID fan

10 Combustor

11 Stack

12 Tar sampling

13 Syngas sampling

14 Analyzer

4-part IFB

Feedstock

• Mixed Wood Pellet

– Has been used for boiler to

reduce the demand of coal

– Potential feedstock for gasifier

12Mixed Wood Pellet

Ultimate analysis (wt.%, daf) Proximate analysis (wt.%, a.r.)

C 49.52 Moisture 9.95

H 6.26 Volatile 88.29

O 43.50 Fixed carbon 0.75

N 0.72 Ash 1.02

S 0.00 HHV (MJ/kg) 17.69

Testing Parameters

• Parameters studied– Temperature

– Gas velocity in lean bed

– To investigate the effect on

syngas composition

• Parameters kept constant – Gas velocity in dense bed

– Equivalence Ratio (ER)

– The effect of ER will be conducted

in further work

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Condition Parameters

Temperature (°C) 700, 750, 800

Dimensionless Gas velocity in

lean bed (U/Umf)2, 3, 4

Dimensionless Gas velocity in

dense bed (Udb/Umf)1.1

Equivalence Ratio (ER) 0.2

U: gas velocity

Umf: minimum fluidization velocity

Results - Bed Temperature-Gasification (1/3)

• Effect of bed temperature on syngas composition in the

gasification zone

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U / Umf = 2– Temperature

• CO, H2

• CO2, CH4,

• CnHm

– The increase amount of CO/H2 seems to be associated with the decomposition of CH4, CnHm

Results-Bed Temperature-Gasification(3/3)

• Effect of bed temperature on syngas composition in the

gasification zone

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– Temperature • CO, H2

• CO2, CH4, CnHm

– The trend of lower residence time case (U/Umf = 4) is similar to that of higher one (U/Umf = 2)

– Effect of temperature on the CnHm content in the former is more sensitive than that in the latter

U / Umf = 4

Results - Bed Temperature-Gasification (2/3)

• Effect of bed temperature on syngas composition in the

gasification zone

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– Temperature • CO

• H2

• CO2

• CH4

• CnHm

– Inconsistent data in the Case with

750°C

– More study is needed to reexamine the

inconsistency of gas composition at

750°C

U / Umf = 3

Results - Gas Velocity (1/2)

• Effect of gas velocity on syngas composition in the

gasification zone

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– Gas velocity

• CO, CH4, H2

• CO2, CnHm

• Higher gas velocity enhances

the mixing phenomena,

• three reactions are enhanced to

increase the yield of CO and H2

700 °C

CH4 + CO2 → 2CO + 2H2

CnHm + nH2O → 2nCO + ( m/2)H2

C + H2O → CO + H2

Results-Gas Velocity(2/2)

• Effect of gas velocity on syngas composition in the

gasification zone

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– Gas velocity

• CO, CH4, H2

• CO2, CnHm

• Higher

– Highest CO and H2 could be

found at 800°C and U/Umf = 4

– Higher temperature (900°C) tests

will be conducted in further work to

check the gasification performance

800 °C

Results - Bed Temperature-Combustion

• Effect of bed temperature on gas composition in the

combustion zone

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U / Umf = 2 U / Umf = 3 U / Umf = 4

• CO2 concertation is detected in all cases Char (unburmed carbon)

from gasification zone is converted into CO2

– heat is released via combustion (exothermic reaction)

– Then, energy is transferred for gasification (endothermic reaction).

Summary and Future Work (1/2)

• IFB is verified to be employed in gasification application

• The major trend shows that the contents of valuable gases insyngas increase with the temperature and gas velocity

• Gas composition in the combustion zone shows the residue of carbon content is converted to CO2, and the energy used to heat up the bed material– To recover the energy and increase the gasification efficiency

– The IFB could be applied as the indirect gasification with adopting steam as gasified agent

• Effect of temperature and gas velocity on tar content is inconsistent,further study is needed to investigate the issue

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Summary and Future Work (2/2)

• Effect of operation parameters– Temperature be increased to 900°C (this study: 700°C~800°C)

– Equivalence ratio (ER) be increased to 0.4 (this study: 0.2)

• Effect of geometry– The height of the reactor will be extended, to investigate the effect on

tar content and syngas composition

• Effect of gasified agent– Pure steam gasification to yield the syngas with N2-free product

– Metal oxides used as bed material to provide the O2, to crack the tar, and other function based on the type of metal oxides

– Trace gas will be adopted in the gasified agent to check the separation of the two gases in the two reaction zones

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Yau-Pin CHYOU, Ph. D. Clean Carbon as Sustainable Energy (CaSE) Program

Institute of Nuclear Energy Research (INER)

E-mail: ypchyou@iner.gov.tw

Q & A

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