Chemical Looping Technology

L. S. Fan

Department of Chemical and Biomolecular Engineering

The Ohio State University Columbus, Ohio 43210

by

Columbia University April 16, 2014

2

Full Oxidation in Chemical Looping Applications for Fossil Fuel Conversions

Two typical types of looping reaction systems

Oxygen Carrier (Type I)

Me/MeO, MeS/MeSO4

CO2 Carrier (Type II)

MeO/MeCO3

“1st Meeting of High Temperature Solids Looping Cycle

Network”, Oviedo, Spain, September 15-17 (2009).

“1st International Conference on Chemical

Looping”, Lyon, France, March 17-19 (2010).

Selective Oxidation in Chemical Looping Applications for Fossil Fuel Conversions and Solar

Chemical Looping Systems

CH4 or other Carbonaceous Fuels

CH4 or other Carbonaceous Fuels

Syngas CO + H2

Chemicals

Solar Energy/ Nuclear Energy

H2O H2+ O2

chemical looping chemical looping chemical looping

0

10

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0 20 40 60 80 100

% Electricity

Ov

era

ll P

roc

es

s E

ffic

ien

cy

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10

20

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60

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80

90

SCL

Gasfication-WGS

IGCC-SELEXOL

Subcritical MEA

Ultra-supercritical MEA

Ultra-Supercritical Chilled Ammonia

Syngas CLC

H2 Membrane WGS

CO2 Membrane WGS

CDCL

Comparison of OSU SYNGAS and Coal Direct Chemical Looping (CDCL) Processes with Traditional Coal to Hydrogen/Electricity

Processes

Assumptions used are similar to those adopted by the USDOE baseline studies.

5

ε ≈ 1

Partial oxidation

/Gasification

ε = 0.88

H2 + CO

407.7 kJ

358.9 kJ

0 Heat Loss

48.8 kJ Exergy Loss

Water Gas Shift

H2 +CO2

393.4 kJ

322.9 kJ

ε = 0.82

ε = 0.89

Fe

514.8 kJ

456.4 kJFe3O4 @1023K

(0.395 mol)

107.1 kJ

71.9 kJ

ε = 0.669

14.3 kJ Heat Loss

36 kJ Exergy Loss

H2 + Fe3O4

485.5 + 107.1 kJ

396.9 +71.9 kJ

ε = 0.82

Carbon

407.7 kJ/mol

407.7 kJ/mol

23.2 kJ Exergy Loss77.8 kJ thermal

energy @ 380 K

12.41kJ Exergy

ε = 0.16

Partial oxidation

I

II

Substance

Enthalpy of degradation

Exergy

Exergy Rate (ε)

Energy/Exery Loss

Additional Energy Input

Final Product

ε ≈ 1

Partial oxidation

/Gasification

ε = 0.88

H2 + CO

407.7 kJ

358.9 kJ

0 Heat Loss

48.8 kJ Exergy Loss

Water Gas Shift

H2 +CO2

393.4 kJ

322.9 kJ

ε = 0.82

ε = 0.89

Fe

514.8 kJ

456.4 kJFe3O4 @1023K

(0.395 mol)

107.1 kJ

71.9 kJ

ε = 0.669

14.3 kJ Heat Loss

36 kJ Exergy Loss

H2 + Fe3O4

485.5 + 107.1 kJ

396.9 +71.9 kJ

ε = 0.82

Carbon

407.7 kJ/mol

407.7 kJ/mol

23.2 kJ Exergy Loss77.8 kJ thermal

energy @ 380 K

12.41kJ Exergy

ε = 0.16

Partial oxidation

I

II

Substance

Enthalpy of degradation

Exergy

Exergy Rate (ε)

Energy/Exery Loss

Additional Energy Input

Final Product

I. Contional Process

Exergetic Efficiency

322.9/407.7 = 79.2%

II. Chemcial Looping Process

Exergetic Efficiency

396.9/(407.7 + 12.41)=94.5%

Exergy Analysis on Hydrogen Production

Economics on Chemical Looping Process

Thomas, T., L.-S. Fan, P. Gupta, and L. G. Velazquez-Vargas, “Combustion Looping Using Composite Oxygen Carriers” U.S. Patent No. 7,767,191 (2010, priority date 2003)

The CDCL process can be also used for high efficient hydrogen production

Reducer

Combustor

Pump

Coal Prep.Coal

CO2

compressor

Particulate Removal

FGD Stack

CO2

Sequestration

LPIPHP

Air

Fe2O3

Cooling Tower

ID Fan

Water

ID Fan

H2O

CO2+H2O

Enhancer Gas Recycle Fan

Electricity

Carrier Particle Makeup (Fe2O3)

Fly Ash and Carrier Particle Fines

FGD

Spent Air

Steam

WaterSteam Cycle

FeO/Fe

Existing equipment for repowering case

Existing equipment for repowering case

Existing equipment for repowering case

Base Plant

MEA Plant

CDCL Plant

First-Year Capital ($/MWh) 31.7 59.6 44.2

Fixed O&M ($/MWh) 8.0 13.0 9.6

Coal ($/MWh) 14.2 19.6 15.9

Variable O&M ($/MWh) 5.0 8.7 8.7

TOTAL FIRST-YEAR COE ($/MWh)

58.9 100.9 78.4

∆ = +71%

∆ = +33%

• Retrofit to conventional coal combustion process • CDCL replaces existing PC boiler

– Additional equipment for CO2 compression and transportation required

• Techno-Economic analysis performed comparing CDCL to Base Plant with no CO2 capture and 90% CO2 capture via post-combustion MEA process

Large Scale Chemical Looping Process Demonstration

Organization Process/Type Capacity Features

Hunosa, Spain CaOling – CaO looping / Type II 2 MWth Pilot plant to capture CO2 from the flue

gas from 50 MWe coal power plant

Technical University of

Darmstadt, Germany LISA – limestone-based

absorption of CO2 / Type II 1 MWth Capture plant is an extension to a 1052

MWe hard coal-fired power plant

Industrial Technology

Research Institute (ITRI),

Taiwan

Carbonation-calcination and

carbonation-calcination-hydration

(Ohio State CCR process) looping

reactions to capture CO2 / Type II

2 MWth Limestone sorbents are used with spent

CaO fed to cement industry

Technical University of

Darmstadt, Germany ECLAIR - emission free chemical

looping coal combustion process

using ilmenite / Type I

1 MWth The pilot unit is for solid fuel conversion

and designed based on CFB concept

Alstom, U.S. Calcium sulfate chemical looping

combustion / Type I 3 MWth The oxygen carriers are CaS/CaSO4

Ohio State University, U.S. High pressure syngas chemical

looping (SCL) gasification process

using iron based oxygen carrier /

Type I

250 kWth -

3MWth SCL enables high purity hydrogen

production with in-situ CO2 capture via

countercurrent moving bed reactor design;

Syngas is from KBR gasifier

B&W and OSU Chemical Looping Combustion – 3 MWth Pilot Demonstration (see B&W press release; work in progress)

Ellingham Diagram: Selection of Primary Metal

Oxygen Carrier Particle Development

Core-Shell Particle Formation through Cyclic

Gas-Solid Reactions

4Fe (s) + 3O2 (g) 2Fe2O3 (s) (1)

Fe2O3 (s) + 3H2 (g) 2Fe (s) + 3H2O (g) (2)

If the cyclic reactions proceed through

Fe cation diffusion, core-shell structure

forms, e.g. Fe2O3 + Al2O3.

If the cyclic reactions proceed through

O anion diffusion, core-shell structure

does not forms, e.g. Fe2O3 + TiO2.

*Al2O3 is only a physical support, while TiO2 alters the solid-phase ionic diffusion mechanism

Fe2O3+Al2O3 VS Fe2O3+TiO2

after 50 redox

cycles

after 50 redox

cycles

Modes of CFB Chemical Looping Reactor Systems Mode 1- reducer: fluidized bed or

co-current gas-solid (OC) flows Mode 2 - reducer: gas-solid (OC) counter-

current dense phase/moving bed flows

Thomas, T., L.-S. Fan, P. Gupta, and L. G. Velazquez-Vargas, “Combustion Looping Using Composite Oxygen Carriers” U.S. Patent No. 7,767,191 (2010) (priority date:2003).

OSU CLC System Chalmers University CLC System

Fuel

CO2 H2O CO2, H2O

Moving Bed Reducer

Fuel

Fluidized Bed Reducer

12

Chemical Looping Reactor Design

FeOy

FeOx

CO/H2

CO2/H2O

(x>y)

FeOy CO/H2

(x>y)

FeOx CO2/H2O

Fluidized Bed Moving Bed

FeOy CO/H2

(X>Y)

FeOx CO2/H2O

Fluidized Bed Moving Bed

Moving Bed – The Selected Reactor Type

FeOy

FeOx

CO/H2

CO2/H2O

(X>Y)

Fluidized Bed v.s. Moving Bed

Maximum Solid Conversion

Gas Velocity

Particle Size

11.11%

> Umfv

Small

50.00%

< Umfv

Large

Fluidized Bed v.s. Moving Bed

Maximum Solid Conversion

Gas Velocity

Particle Size

11.11%

> Umfv

Small

50.00%

< Umfv

Large

Maximum Solid Conversion

Gas Velocity

Particle Size

11.11%

> Umfv

Small

50.00%

< Umfv

Large

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

200 400 600 800 1000

Temperature (C)

PC

O2/P

CO

Fe2O3

Fe3O4

FeO

Fe

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

200 400 600 800 1000

Temperature (C)

PC

O2/P

CO

Fe2O3

Fe3O4

FeO

Fe

Fluidized Bed

Moving Bed

(x>y)

OSU SYNGAS Chemical Looping Process

Possible Oxygen Carriers:

Fe2O3 – Fe / FeO

Main reactions:

General Observations: • 2 Moving Bed + 1 Entrained bed reactors • Very High Fuel Conversion • Near 100% in-situ CO2 capture • High Purity H2 generation • High Solid Conversion • Low Solid Circulation Rate

Fe3O4 + O2 → Fe2O3 + Heat

Overall reaction

CxHyOz+H2O/O2→ CO2 + H2/Heat

CxHyOz+ Fe2O3 → CO2 +H2O + Fe

Fe + H2O → Fe3O4 + H2

Reducer

Oxidizer

Combustion

Train

Red

uce

r O

xid

izer

Co

mb

ust

or

Carbonaceous Fuel

Fe / FeO

Fe 2 O 3

CH

EMIC

AL

LOO

PIN

G

Red

uce

r O

xid

izer

Co

mb

ust

or

CO2 & Steam

H2 & Steam

Steam

Fe / FeO

Fe3O4

Fe 2 O 3

Air

Depleted Air

25 kWth OSU Sub-Pilot SCL Unit Reducer Gas Composition

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1:33:36 PM 2:09:36 PM 2:45:36 PM 3:21:36 PM

Co

nce

ntr

atio

n (

%)

H2

CO

CO2

Oxidizer Gas Composition

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8:52:48 AM 10:19:12 AM 11:45:36 AM 1:12:00 PM

Co

nce

ntr

atio

n (

%)

H2

CO

CO2

Recent Unit Demonstration

• Over 300+ hours operation • Average CO2 purity generated

throughout run > 99% • >99.99% hydrogen purity at steady

state • Steady Pressure Profile throughout

Test run

-2

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Pressure("H20)

Hours

DP2

DP3

DP4

Differential Pressure Profile

Once-Through Reducer Carbon Conversion Profile Reducer Gas Concentration Profile

200+ Hour Sub-Pilot Continuous Run - Sample Results

0%

1%

1%

2%

2%

3%

3%

4%

4%

5%

5%

90%

91%

92%

93%

94%

95%

96%

97%

98%

99%

100%

0 50 100 150 200

Co

ncen

trati

on

CO

, C

H4,

O2 (

%)

Co

ncen

trati

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CO

2 (

%)

Time (min)

CO2

CO

CH4

CH4

CO2

CO

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Carb

on

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(%

)

Time of reaction (min)

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Co

nc

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CO

, C

H4

, C

O2

Co

nc

en

tra

tio

n (

%)

O2

Time (min)

CO2

O2

CO

CH4

Combustor Gas Concentration Profile

Reducer Combustor

SOx (ppm) 190-1170 0 - 70

NOX (lb/MMBTU) 0.100 – 0.200* ~ 0

1. NETL. Cost and Performance Baseline for Fossil Energy Plants Volume 1 & 3b

*Conventional PC Boiler NOx Generation = 0.2 – 0.5 lb/MMBTU1

CDCL NOx/SOx Analysis

• Continuous steady >90% carbon conversion from reducer throughout all solid fuel loading (5- 25kWth)

• <0.25% CO and CH4 in reducer outlet = full fuel conversion to CO2/H2O

• <0.1% CO, CO2, and CH4 in combustor = negligible carbon carry over, nearly 100% carbon capture

1 MWth Chemical Looping Combustion System

Alstom – Darmstadt MeOx1 The Ohio State University - CDCL

Ht: 1.83 m ID: 1.17 m Vol: 1.96 m3

Ht: 0.61 m ID: 1.17 m Vol: 0.65 m3

Ht: 11.37 m ID: 0.41 m Vol: 1.42 m3

Ht: 8.66 m ID: 0.59 m Vol: 2.37 m3

> 11.37 m < 9 m

Total Reactor Volume: 3.80 m3 • No internal mechanical moving parts • Packed moving bed design increases oxygen

carrier conversion reducing solid flow rate • In-situ ash separation • Scalable reactor design • Simple design – no loop seals/carbon strippers

1. Abdulally, I. et al. Clearwater Clean Coal & Fuel Conference 2012 43–54.

Total Reactor Volume: 2.61 m3

• Mechanical solid conveying • Carbon stripper required • Multiple components – difficult to integrate