Institute of Chemical Engineering: Future Energy Technology Prof. Hermann Hofbauer www.vt.tuwien.ac.at

Chemical looping combustion using biomass as fuel Stefan Penthor, Tobias Pröll, Hermann Hofbauer

2nd Oxyfuel Combustion Conference, 12-16 September 2011, Yeppoon, Australia

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Outline

• Introduction

• Challenges and why biomass

• Solutions

• Modeling

• Results

• Conclusion/Outlook

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

What is CLC?

Cooling/

Condensation

Air

Air Reactor

(AR)

Fuel Reactor

(FR)

MeOx-1

MeOx N2, (O2) CO2, (H2O)

H2O

CO2

Steam

Solid Fuel

Unique potential for CCS - air and fuel are never mixed!

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Challenges • Decomposition of fuel

• Conversion of combustible gas species

• Avoiding loss of carbon to air reactor

• Separating ash from oxygen carrier

• Finding suitable oxygen carrier

• Finding suitable reactor concept

Objectives

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Why biomass?

Petroleum coke

South African coal

Woody biomass

Volatiles [%] 10 21.6 80

Moisture [%] 8 8.3 25

Ash [%] 0.5 15.9 1.5

• Reactive char (compared to coal)

• Carbon neutral, low sulfur

• Below zero emission

• Stopover to coal

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Solutions

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

0

100

200

300

400

500

600

700

800

900

1000

1100

0 100 200 300

heig

ht [m

m]

pressure gradient [mbar/m]

0

100

200

300

400

500

600

700

800

900

1000

1100

0 10 20 30 40 50

heig

ht [m

m]

pressure drop [mbar]

Cold flow model tests

Schmid J.C., et al., Int. Conference on Polygeneration Strategies, 2011

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Modeling

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

• Mass & energy balance

• Basic char gasification kinetics

• Chemical equilibrium for CO and H2 oxidation

• Solids segregation

Modeling approach

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Solids segregation

φi=mi,out,top

mi,out,bottom i=OC, Ash, Char

OC

AshSolids

Char

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

First results

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

• Pth = 1 MW

• Ilmenite as oxygen carrier

• • = 1.2

• Steam/Carbon = 0.5

• • OC = 0.05

• • Ash = 0.2

• • Char = 0.1

• •Char = 9 - 20 s

• TLLS = 950 C

Base case

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

1

2

3

4

5

6

7

8

900 1000 1100

Reac

tion

Zone

[-]

Temperature [°C]

• TAR = 1015 C

• • sep, CO2 = 92.0 %

• Ash accumulation:

• xAsh,ILS = 37.4 %

• xAsh,LLS = 13.1 %

Fuel feed

Base case

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

0

10

20

30

40

0.05 0.15 0.25 0.35

Ash

co

nce

ntr

atio

n [w

t%]

• _Ash [-]

LLS @ 5kg/h OC make up

ILS @ 5kg/h OC make up

LLS @ 10kg/h OC make up

ILS @ 10kg/h OC make up

• Ash variation

Base case

CLC using biomass as fuel Stefan Penthor

Institute of Chemical Engineering Future Energy Technology

Conclusions/Outlook

• Multistage CFB can be key to solid fuel CLC

• Gas-solid contact and residence time improved

• Selective ash removal possible

• Process model created, validation necessary

• Cold flow model testing

• Build 100 kW pilot plant

Institute of Chemical Engineering: Future Energy Technology Prof. Hermann Hofbauer www.vt.tuwien.ac.at

Thank you for your attention!

Contact: Stefan Penthor

stefan.penthor@tuwien.ac.at www.chemical-looping.at