Electrochemical Technology Program Argonne ... - Energy.gov · DOE/EE/HFCIT Program of Energy Even with deactivation, Pt-Re catalyst should be able to meet GHSV target 2.0 2.5 3.0

Hydrogen, Fuel Cells, and Infrastructure TechnologiesOffice of Energy Efficiency and Renewable EnergyU.S. Department of Energy

Water gas shift catalysis

Theodore Krause, Razima Souleimanova,John Krebs, and Mario Castagnola

Electrochemical Technology Program

Argonne National Laboratory

May 24-27, 2004

This presentation does not contain any proprietary or confidential information

2

PioneeringScience andTechnology

Office of Science U.S. Department

of EnergyDOE/EE/HFCIT Program

Objectives

• To develop advanced water-gas shift (WGS) catalyststo meet the DOE performance requirements

Compared to Cu-Zn and Fe-Cr WGS catalysts, these newcatalysts will be

more active (higher turnover rates)

less prone to deactivation due to temperature excursions

more structurally stable (able to withstand frequent cycles ofvaporizing and condensing water)

more resistant to sulfur poisoning

Improve our understanding of reaction mechanisms, catalystdeactivation, and sulfur poisoning

Define operating parameters (e.g. steam:carbon ratios,temperature, gas hourly space velocities (GHSV), catalystgeometry) to optimize catalyst performance and lifetime

3




Budget, technical barriers and targets• FY04 Funding: $600K

• Technical barriers

A. Fuel Processor Capital Costs

G. Efficiency of Gasification, Pyrolysis, and Reforming Technologies

Z. Catalysts

AB. Hydrogen Separation and Purification

• Technical targets for water gas shift catalysts

gas-hourly space velocity (GHSV) 30,000 h-1

CO conversion 90% and selectivity 99%

lifetime > 5000 h

cost <$1/kWe

4




Approach• Identify metal(s) and oxide combinations which promote

one or more elementary reaction steps (e.g. CO oxidation,H2O dissociation, formate/formyl decomposition) involvedin the water-gas shift reaction

• Evaluate the water-gas shift activity of these materials in amicroreactor system

• Use characterization techniques (e.g. X-ray spectroscopy,temperature-program reduction (TPR), and electronmicroscopy) to identify factors needed to improve WGSactivity or to minimize catalyst deactivation

• Develop kinetic model to predict catalyst performance forreformer operating parameters

5




Project safety

• Internal safety reviews are performed for all aspects ofthis project to address ESH issues

Catalyst synthesis

• Synthesis procedures are performed in fumehoods toexhaust vapors of powders and solvents

• Waste chemicals are collected and disposed of throughthe Laboratory’s Waste Management Operations

Microreactor systems

Located in fumehoods

Equipped with safety interlocks that shut the systemdown if excessive temperature or pressure is sensed orthe fumehood ventilation fails

• Safety reviews are updated and renewed annually

6




Project timeline

Oct 1997: Initiatedwork on Pt shiftcatalyst

May 1999: Began work onnon-precious metalcatalysts

Mar 2003:Demonstrated Pt-Re with higheractivity and betterstability than Pt

Oct 2000: Optimized Cu-mixedmetal oxide formulation Oct 2002: Began

work on Pt bimetallicformulation

May 2002: Demonstrated90% conv., <0.1 kg/kWe,$0.9/kWe with Cu catalyst

June 2003: Begin testingof catalysts supported onmonoliths and foams

Aug 1999: DemonstratedPt catalyst with 0.14 wt%loading

May 2001:Demonstrated Co andRu promoted catalyst

May 2000:Demonstrated Cu-mixed metal oxidecatalyst

Jan-Mar 2004:Completed kineticstudy of Pt-Re andreactor modelinganalysis

Apr 2004: Demonstratedimproved base metalcatalyst

Oct 2003: Determinedoptimal compositionfor Pt-Re

7




Addition of Re improves performance of Pt-ceria catalyst

0

1

2

3

4

5

6

7

8

200 250 300 350 400 450

Temperature, °C

0.91 wt%Pt - 0.95 wt%Re

0.92 wt%Pt - 1.79 wt%Re

1.81 wt%Pt - 1.77 wt%Re

0.87 wt%Pt

1.51 wt% Pt

2.86 wt% Pt

-0.5-10.5011Pt*

-0.17-0.580.40016Pt-Re

dcba Ea(kcal/mol)

0

100

200

300

400

500

600

200 250 300 350 400 450 500

Temperature, °C

cat*s

1.81%Pt - 1.77%Re

0.87%Pt

0.91%Pt - 0.95%Re

2.86%Pt

0.92%Pt - 1.79%Re

Rate Equation: exp(-Ea/RT)*COa*H2Ob*H2

c*CO2d

*Ref: T. Bunluesin et al. Appl. Catal. B, 15 (1998) 107-114.

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TPR and extended X-ray absorption fine structure(EXAFS) analysis suggests that Re stabilizes Pt

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 1 2 3 4

R, Å

FT

((

(k)*

k3)

Pt-Re - as prepared

Pt-Re - 300oC

Pt - 300oC

Pt-Re - 400oC

Pt - 400oC

Pt - as prepared

0

5

10

15

20

25

0 100 200 300 400 500

Temperature, oC

TC

D R

esp

on

se, arb

itra

ry

Pt-Re - 1st TPR

Pt - 1st TPR

Pt - 2nd TPR

Pt-Re - 2nd TPR

• For Pt, shift in reductionpeak to lower temperature isindicative of particle growth

• For Pt-Re, no change inreduction profile

• More Pt-Pt bond formation inPt than Pt-Re after 100+ h onstream at 400°C

9




Even with deactivation, Pt-Re catalyst should beable to meet GHSV target

2.0

2.5

3.0

3.5

4.0

4.5

5.0

280 300 320 340 360 380 400 420 440

Inlet temperature, oC

S/C

- s

tea

m-t

o-c

arb

on

ra

tio

20,000 h-1

20,000 h-1

w/deact

30,000 h-1 30,000 h

-1

w/deact

40,000 h-1

w/deact40,000 h

-1

0

10

20

30

40

50

60

70

80

90

0 100 200 300 400 500

Time on stream, h

cat*s

ec

)

5 ppm H2S

25 ppm H2S

50 ppm H2S

• Pt-Re lost about 50% of itsinitial activity during the first250 hours, but the activitythen stabilized

• Modeling study shows that 1%CO can be achieved even withdeactivation if the temperatureand S/C ratio are increased

10




Optimal geometric support for WGS catalyst -foam or monolith?

• Both modeling and experimental studies show that theremay be a slight benefit to using a foam as a support

• However, the monolith is the preferred support based oncost and production capacity

0

10

20

30

40

50

60

70

80

90

100

240 260 280 300 320 340 360 380 400 420

Exit Temperature, oC

CO

co

nvers

ion

, %

600-cpi Monolith

- 30,000 h-1

Equilibrium

600-cpi Monolith -

45,000 h-1

Foam - 30,000 h-1

Foam - 45,000 h-1

0

10

20

30

40

50

60

70

80

90

100

240 260 280 300 320 340 360 380 400 420

Exit temperature, °C

CO

co

nvers

ion

, %

Foam - 5% relative density

400-cpi Monolith

600-cpi Monolith

Equilibrium

GHSV = 30, 000 h-1

11




Even with the higher activity of the Pt-Re, stillhigher activity is needed to meet the cost targets

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250

Catalyst loading, g/L

CO

co

nvers

ion

, %

S/C=1.4 Tin=400oC

S/C=3 Tin=400oC

S/C=1.4 Tin=350oC

S/C=3 Tin=350oC

• Modeling studies suggestthat the optimal catalystloading on the structuredsupport is 50-150 g/L

0

2

4

6

8

10

12

400-cpi

monolith

600-cpi

monolith

Ceramic

Foam

Metal

Foam

Structured Support

$/k

We

Support

Support + CeO2

Support + CeO2 + 1 wt%Pt - 50g/L

Support + CeO2 + 1 wt% Pt - 150g/L

Target of $1/kWe

Pt price of $893/oz (4/5/04)

• The $1/kWe target is toughto achieve

12




We are investigating less-costly precious metalbimetallic catalysts

0

20

40

60

80

100

200 250 300 350 400 450 500

Temperature, oC

CO

co

nvers

ion

, %

600-cpi monolith

1200-cpi monolith

equilibrium

GHSV = 30,000 h-1

• A combination of a preciousmetal (PM)-base metal (BM) hasbeen identified that exhibitshigher WGS activity than eitherthe PM or BM

• The equilibrium-predictedCO conversion isachieved at a GHSV of30,000 h-1 at >340oC

• Long-term stability is yetto be verified

0

100

200

300

400

500

600

250 300 350 400 450 500

Temperature, oC

cat*

se

c)

1x PM + 3x BM

2.5x PM + 3x BM

7.5x PM + 3x BM

2.5x PM + 1x BM

13




Base metal WGS catalysts may also bepossible

0

20

40

60

80

100

120

140

160

180

200

240 260 280 300 320 340 360 380 400 420

Temperature, °C

cat*

s)

1X - Precursor A

2X - Precursor A

1X - Precursor B

2X - Precursor B

0

50

100

150

200

250

240 260 280 300 320 340 360 380 400 420

Temperature, °C

cat*

s)

0

20

40

60

80

100

CO

to C

O2 s

ele

ctiv

ity, %

Support B

Support A

• The choice of precursor and oxide support were critical factorsfor optimizing activity

• The catalyst promotes methanation; however,

• The selectivity of CO to CO2 does not depend on the precursor orsupport

14




A critical factor for the base metal catalyst is to preventformation of the oxide and surface interactions

0

10

20

30

40

50

60

240 260 280 300 320 340 360 380 400 420

Temperature, °C

cat*

s)

Precursor A

Pretreatment 1

Precursor B

Pretreatment 1

Precursor A

Pretreatment 2

Precursor B

Pretreatment 2

0 200 400 600 800

Temperature, °C

no

rmalized

TC

D s

ign

al, a

rbit

rary

Precursor B - Pretreatment 1

Precursor B - Pretreatment 2

Bulk Oxide

• Pretreatment has a significantinfluence on catalyst activity

• The most active catalysts havea reduction peak at ~200°C

• The reduction peak at ~700oC isindicative of metal-supportinteraction

15




Comparing the three types of WGS catalysts

0

100

200

300

400

500

600

240 260 280 300 320 340 360 380 400 420

Temperature, °C

cat*

s)

Base Metal

PM + Base Metal

Pt+Re

• Pt-Re

Very active shift catalyst

Good stability

High Cost

• PM + Base Metal

Good shift activity

Less costly than Pt-Re

Stability not yet established

• Base Metal

Less active than both Pt-Reand PM + Base metalcatalysts

Methanation and stabilityare yet to be addressed

Lowest cost

16




Can we avoid low temperature shift foron-board reforming?

2.0

2.5

3.0

3.5

4.0

4.5

5.0

280 300 320 340 360 380 400 420 440

Inlet temperature, oC

S/C

- s

tea

m-t

o-c

arb

on

ra

tio

40,000 h-1

isothermal

20,000 h-1

adiabatic

20,000 h-1

isothermal

30,000 h-1

isotherma

30,000 h-1

adiabatic

40,000 h-1

adiabatic

60,000 h-1

adiabatic

60,000 h-1

isothermal

0

10

20

30

40

50

60

70

80

90

100

200 250 300 350 400 450

Inlet Temperature, oC

CO

co

nvers

ion

, %

Pt-Re

12 wt% Cu

8 wt% Cu

Equilibrium

GHSV = 30,000 h-1

Cu kinetics - N. A. Koryabkina et al., J.

Catal. , 217 (2003) 233-239.

• Modeling studies showthat the activity of Pt andCu catalysts decreasessignificantly below 300°C

• Pt-Re can achieve 1% CO at>300°C at GHSV 30,000 h-1

17




Interactions and collaborations

• University of Alabama (Prof. Ramana Reddy) tocharacterize shift catalysts using SEM, TEM, andXPS

• Non-disclosure agreement (NDA) with CatalyticaEnergy Systems to evaluate new shift catalysts

• Provided samples for evaluation

Toyota

Nissan

Süd-Chemie, Inc.

18




Response to reviewers’ comments from FY03

• Monolith work should be given priority

• Improve durability (longer-term endurancetesting is needed)

• Better performance from non-precious metalcatalysts

• Are low temperature catalysts feasible foron-board fuel processing?

19




Milestones

05/04Complete the assessment of the feasibilityof a low temperature non-precious metalcatalyst to meet the DOE targets

09/04Demonstrate <1% CO out using structuredcatalyst(s) for >500 h

05/04Determine the optimal bimetallicformulation for the Pt-based shift catalyst

01/04Determine the optimal operatingconditions for the water-gas shift reactor

DateMilestone

20




Future work

• For bimetallic precious metal-base metal and base metalcatalysts

Optimize formulation to increase activity and minimize methanation

Improve our understanding of reaction mechanisms

• To improve catalyst durability and minimize deactivation

Conduct characterization studies of spent catalysts to furtherunderstand deactivation mechanisms

Conduct long-term tests of improved catalyst formulations

• Address catalyst issues identified in “FASTER” Program

Catalyst deactivation and structural stability issues (i.e., effect offrequent and rapid startup)

Obtain performance data as a function of operating parameters todevelop kinetic models

Electrochemical Technology Program Argonne ... - Energy.gov · DOE/EE/HFCIT Program of Energy Even with deactivation, Pt-Re catalyst should be able to meet GHSV target 2.0 2.5 3.0

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