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Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Intrinsic Reactivity Investigations of Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,Biomass and Coal Chars,

and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends and their Blends

Naoko Ellis Naoko Ellis Naoko Ellis Naoko Ellis and Mohammad Masnadi

Chemical and Biological Engineering

Clean Energy Research Centre

University of British Columbia

Canada

David J. Harris and Daniel G. Roberts

CSIRO Energy Technology

Kenmore, QLD

Australia

ContentContent• Canadian perspective

• Motivation

• Co-gasification

• Australian coal and Canadian biomass

• Experimental

• Char generation and characterization

• Fixed bed char reactivity study

• Future work

• Gasification research at UBC

• Invitation to Vancouver

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Canada’s Energy SystemCanada’s Energy System

3333Source: http://dev3.centreforenergy.com/FactsStats/MapsCanada/CA-EnergyMap.asp

Canadian CoalCanadian Coal

• Production: 65-75 Mt annually

• >40% exported

• Consumed 58 million tonnes of coal in 2006

• Most used to generate electricity• 74 % in Alberta, 63 % in Saskatchewan, 60 % in Nova Scotia,

and 18 % in Ontario from coal

• Clean coal technology: CO2 capture4444Source: http://www.nrcan.gc.ca/energy/sources/1205

Canada’s Energy MixCanada’s Energy Mix

5555http://www.neb-one.gc.ca/clf-nsi/rnrgynfmtn/nrgyrprt/nrgyftr/2011/fctsht1134mrgngfl-eng.html

Motivation Motivation Co-gasification of coal and biomass

• Coal:

• High energy density

• Conventional technology

• Supply network

• Biomass:

• Renewable

• Logistics and infrastructure issue

• Reactive

• High tar content

• Additionally:

• Catalytic/synergistic effect on gasification

• Lower tar content

6666

flux

O2

CO/CO2

slag

CO2 and H2O

CO + H2

Coal Conversion in GasificationCoal Conversion in Gasification• Coal gasification is a multi-stage process

• Coal pyrolysis

• Rapid volatile release

• Determines char yield and morphology

• Combustion

• Limited, fast. O2 consumed early in process

• Exothermic, provides heat for endothermic gasification reactions

• Char Gasification

• Slow, rate determining. Endothermic

• CO2 and H2O converted to CO and H2.

• Slag formation and flow

• Flux may be required to achieve adequate viscosity

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FeedstockFeedstock

Coal (CRC272)Coal (CRC272)Coal (CRC272)Coal (CRC272) BC PineBC PineBC PineBC Pine

Proximate (%, db)Proximate (%, db)Proximate (%, db)Proximate (%, db)

air dried moisture 2.3 7.0

ash 10.1 1.0

volatile matter 35.0 78.0

fixed carbon 52.6 14.0

Ultimate Ultimate Ultimate Ultimate (% (% (% (% dafdafdafdaf))))

Cabon 82.6 51.7

Hydrogen 5.36 5.97

Nitrogen 1.68 0.18

Sulfur 1.04 0.04

Oxygen (diff) 9.4 42.2

8888

Char PreparationChar Preparation• Samples prepared from Australian coal and Canadian pine

• Tube furnace at 900°C

• Sized samples (-1.0 +0.6 mm) of coal, biomass and blends are placed in a tube furnace under slow pyrolysis conditions

• Heating rate of 20°C/min under Nitrogen for 2 hrs holding time

• Resulting char is crushed and sieved to -1.0 +0.6 mm size range

• Char yield based on as received weight ratio

9999

Moisture Volatiles

Biomass 7.2% 71.4%

Coal 1.8% 33.5%

0.0 0.2 0.4 0.6 0.8 1.0

20

30

40

50

60

70

Ch

ar

Yie

ld, w

t%

Biomass wt ratio, -

Char Surface AreaChar Surface Area

10101010

0.0 0.2 0.4 0.6 0.8 1.0

200

300

400

500

600

0

20

40

60

80

100

Surf

ace A

rea

DR m

2/g

Biomass wt. ratio, -

Surface area DR

m2/g

BET m2/g

BE

T m

2/g

Char Surface AreaChar Surface Area

11111111

0.0 0.2 0.4 0.6 0.8 1.0

200

300

400

500

600

0

20

40

60

80

100

Su

rfa

ce A

rea

DR m

2/g

Biomass char wt. ratio, -

Surface area DR

m2/g

BET m2/g

BE

T m

2/g

Char ReactivityChar ReactivityCO2 gasification mechanism

Steam gasification mechanism

12121212Hodge, 2009

Cf + H2O C(O) + H2

C(O) → CO + Cf′

Cf + H2 → C(H2)

Cf + CO2 C(O) + CO

C(O) → CO + Cf′

13131313

COCO22 GasificationGasification

Specific reaction rate at 900ºC

Surface Area EvolutionSurface Area Evolution• CO2 gasification at 10% Conversion

14141414

0.0 0.2 0.4 0.6 0.8 1.0

200

300

400

500

600

700

Initial SA

SA after 10% Conversion

Su

rface

Are

aD

R m

2/g

Biomass wt. ratio left in char, -0.0 0.2 0.4 0.6 0.8 1.0

0

100

200

300

400

500 Initial BET

BET after 10% Conversion

BE

T,

m2/g

Biomass wt. ratio left in char, -

Char ReactivityChar Reactivity

Surface related intrinsic reaction rate

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Initial rate/initial SA

after 10% conversion

Rea

ctio

n r

ate

ba

se

d o

n s

urf

ace a

rea

Biomass char wt. ratio, -

15151515

Activation EnergyActivation Energy• CO2 gasification at 10% Conversion

16161616

0.0 0.2 0.4 0.6 0.8 1.0

200

220

240

260

280

300

Activa

tio

n E

nerg

y, kJ/m

ol

biomass char wt. ratio, -

-1.0 +0.6 mm

-1.0 mm

-0.6 +0.425 mm

Hodge et al. (2010)

Hodge et al., Energy Fuels, 24, 100-107 (2010)

Steam GasificationSteam Gasification

17171717

• Specific reaction rate at 900ºC

Intrinsic Rates and SAIntrinsic Rates and SA• Steam gasification reactivity

18181818

0% 0.1% 0.248% 0.498% 1.0%

0

100

200

300

400

500

600

SA

DR, m

2 /g

wt. % biomass char

initial

after steam gasification

0.0 0.2 0.4 0.6 0.8 1.0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Rea

ctio

n r

ate

base

d o

n s

urf

ace a

rea

Biomass char wt. ratio, -

Initial rate/initial SA

after 10% conversion

Future WorkFuture Work• Ash analysis (low temp analysis)

• Char morphology

• Catalytic effects

• Secondary Ion Mass Spectrometry

• intensity of K+

• Crystalinity

19191919

(a)

(b)

(c)

(a) Coal (b) Fluid coke (c) Switchgrass

University of British ColumbiaUniversity of British Columbia

BC Carbon Tax BC Carbon Tax –– since 2008since 2008

First tax of its kind in North America

21212121

UBC's Vancouver campus:

total GHG emissions (2008) 60,400 CO2-e tonnes

Business as usual approach:

An estimated $50 million in carbon tax and carbon offsets over the next 25 year period

Reducing our GHG emissions will reduce the carbon liability to $33 million.

2 MW Demonstration Layout2 MW Demonstration Layout

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UBC System Summary

Required fuel: 12,000 BDMT/year (2/3 trucks/day)

Net Power: 1.7MWe

Net Thermal:10 MMBtu/hr (80,000 MMBtu/yr)

(~8% of based steam load and ~4% of peak electricity demand)

CO2 Reduction: 5,000 tpy

NexterraNexterra SystemSystem

23232323

Campus as a Living Lab concept

UBC Clean Energy Research CentreUBC Clean Energy Research Centre

• Biomass feedstock and logistics

• Biomass pre-treatment

• Torrefaction and pelletization

• Integrated gasification and looping CO2 capture

• CO2 capture sorbent reactivity (pressure and temp swing)

• CO2 capture sorbent attrition

• Biomass tar cracking unit

• Dual fluidized bed gasifier

24242424

Gasifier Combustor Combustor

Gasi

fier

Gasifier

Com

bust

or

Steam Air Steam Air Steam Air

Syngas Flue gas Syngas

Flue gas Syngas

Flue gas

Biomass Biomass Biomass

(I) (II) (III)

Integrated Fluidization Bed Gasification Integrated Fluidization Bed Gasification with Looping COwith Looping CO22 CaptureCapture

25252525

Gasifier Calciner

Fuel

Sorbent with

CO2

Sorbent

Concentrated

CO2

H2O

Syngas

Overall Goal:To test the most promising material in the UBC pilot plant: gasification and capture

Sorbents being synthesized, prepared,

pelletized, coated and/or tested:

•Calcite

•Limestone•lithium zirconate

•lithium orthosilicate•sodium silicate

Carbon Management CanadaCarbon Management CanadaCarbon Management CanadaCarbon Management Canada

AcknowledgementAcknowledgement

• Natural Sciences and Engineering Research Council of Canada

26262626

A special issue of ‘Fuel’ will feature the most worthy papers from iSGA-3

For more information go to: www.isga3.com

Building on successful iSGA conferences in China (2008) and Japan (2010).

iSGA-3 will cover the science, technology and policy of gasification of coal,

biomass and other carbonaceous feedstocks, as well as applications to power generation, production of liquid fuels, and related topics.

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