Lean NOx Catalysis Research and Development

Carrie Boyer, Svetlana Zemskova, Paul Park, Lou Balmer-Millar

Advanced Materials Technology

Dennis Endicott, Steve Faulkner

Engine Research

Caterpillar: Engine Research &Advanced Materials Technology 2

Catalyst Research & Development

Application EngineeringFundamental Understanding

Hydrocarbon Reforming NOx

Reduction

Alumina

Catalyst Chemistry

Metal oxide

Caterpillar: Engine Research &Advanced Materials Technology 3

Caterpillar Catalyst Research Facilities

National Lab User Facilities

• XPS (PNNL)

• TEM, SAXS (ORNL)

Catalyst synthesis lab

• Catalyst test lab: two powder benches, Horiba system, multi reactor system (10 reactors)

• Catalyst characterization instruments: BET, XRD, SEM, TPD/TPR, C&S analyzer

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 4

Lean-NOx Catalyst Materials

T

NO

x

active

T

NO

x

selective

! Noble metals (ex. Pt/Al2O3 )

highly active, stablenarrow temperature range, poorly selective (N2O)

! Zeolites (ex. Cu-ZSM-5)active, selectivehydro-thermally unstable

! Metal oxides (ex. Ag/Al2O3 )

highly selective, stable, flexible formulationmoderately active, reductant sensitive

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 5

Alumina Support Materials

" Physical property (SS, PV, PS)

" Chemical property (acidity/basicity)

" Processing (complex agent, pH)

" Inorganic synthesis

- mesoporous alumina material

TEM image of alumina

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 6

Mesoporous Alumina Synthesis

2.4-4.60.21-0.68420-535Pinnavaia

140.61300Stucky

9.91.4566Caterpillar

Pore Size (nm)Pore Volume (cc/g)Surface area (m2/g)

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 7

Performance and Characterization of Ag/Al2O3 Catalysts

! Response to SO2:

Depends on silver loading

Time on Stream (min)0 500 1000 1500 2000 2500 3000

N2 Y

ield

(%)

0

10

20

30

40

50

60NO reduction

Ag2

Ag8

SO2 on SO2 off

2 Θ

0.8

1.5long

30 40 50

short

fresh

Ag8Ag2SO4

Ago

S (wt%)

1900200021002200230024002500

Wavenumber (cm-1)

Ag2 aged short

Ag2 fresh

Ag2 aged long

-NCODRIFT Results

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 8

Active Site Identification of Ag/Al2O3 Catalyst

Temperature (oC)350 400 450 500 550 600

N2 Y

ield

(%)

0

20

40

60

80Ag2SO4 (0.3wt.% S)AgNO3

Ag/Al2O3 Results

Ag2

Temperature (oC)350 400 450 500 550 600

N2 Y

ield

(%)

0

20

40

60Alumina0.5wt.%S/Al2O3

S/Al2O3 ResultsAl2O3

Al2O3 needs to be improved to have more durable catalystCatalytic activity: Ag2SO4 > Ag2O

Fundamental Understanding

Caterpillar: Engine Research &Advanced Materials Technology 9

Engine Testing

• Potential building block for 2007 or 2010 emissions regulations– Low engine out NOx– Low Fuel Penalty

• Aggressive Lean-NOx catalyst formulation for NOx Reduction– Low sulfur content fuel (< 15 ppm S)– Sulfate suppressant additives not required

Advanced Lean NOx Catalysts

This project was undertaken pursuant to an agreement with the United States in connection with settlement of disputed claims in an enforcement action under the Clean Air Act

Caterpillar: Engine Research &Advanced Materials Technology 10

Advanced Lean NOx Catalyst Technology Development

• Screened numerous formulations on Cat engine– Catalysts provided by supplier(s)

• Tested on Cat 3126E 300HT (2000MY)– Two brick catalyst systems– 7.2L, 300 HP, High Torque– 4 gram NOx setup– Tested for highest conversions

# HC/NOx = 3 # HC/NOx = 6

LNOxHighTemp

LNOxLow

Temp

Late Post Injection of Fuel

Dual Brick Systems

LNOxWide

RangeTemp

LNOxWide

Range Temp

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 11

Advanced Lean NOx Catalysis Engine Test Results

0%

10%

20%

30%

40%

50%

225 275 325 375 425 475

Temperature °C

NOx

Conv

ersi

on: P

erce

nt[3:1] Catalyst A[3:1] Catalyst B[3:1] Catalyst C[6:1] Catalyst A[6:1] Catalyst B[6:1] Catalyst C

Space Velocity: 30k – 40k h-1 (stp)

HC/NOx = 6

HC/NOx = 3

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 12

7%22%

6%

17%

9%10%

19%25%

25%

19%

16%

19%

0

200

400

600

800

1000

1200

1400

1000 1200 1400 1600 1800 2000 2200 2400

rpm

Torq

ue (N

*m)

15% Average NOx Reduction

HC/NOx = 3

12-Mode non-idle ESC weighted average

NOx Reduction: ESC Steady-state Modes

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 13

NOx Reduction: ESC Steady-state Modes

32%

23%

38%

39%

38%

15% 12%

20%

27%

29%

8%

8%

0

200

400

600

800

1000

1200

1400

1000 1200 1400 1600 1800 2000 2200 2400

rpm

Torq

ue (N

*m)

260

440480

280

Temperature (oC) 43000 63000

3700020000

Space Velocity (h-1)

24% Average NOx Reduction

HC/NOx = 6

12-Mode non-idle ESC weighted average

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 14

Hydrocarbon & CO Slip

Hydrocarbon Conversion

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

225 275 325 375 425 475 525

Temperature °C

CO C

onve

rsio

n: P

erce

nt

A HC/NOx = 3/1A HC/NOx = 6/1B HC/NOx = 3/1B HC/NOx = 6/1C HC/NOx = 3/1C HC/NOx = 6/1

CO Conversion

DeNOxOnly

Dual Functionality

30%

40%

50%

60%

70%

80%

90%

100%

225 275 325 375 425 475 525

Temperature °C

HC C

onve

rsio

n: P

erce

nt

A HC/NOx = 3/1A HC/NOx = 6/1B HC/NOx = 3/1B HC/NOx = 6/1C HC/NOx = 3/1C HC/NOx = 6/1

DeNOxOnly

Dual Functionality

! Some DeNOx formulations showed dual functionality (Oxicat + Lean-NOx)

! The dual functionality needs to be further optimized.

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 15

Potential for Lean-NOx Catalysis Technology

Benefits• Simplicity

– No core engine modifications are needed

– No infrastructure is required

– Leverages flexible fuel system

– Retrofit opportunities

• Candidate for 20-40% NOx reduction – Building block for added NOx reduction for 2007

• Potential combined Oxicat and Lean-NOx functionality– Marginal passive NOx reduction benefit while

providing oxicat benefits

Substrate

LNOxHighTemp

LNOxLow

Temp

Late Post Injection of Fuel

Application Engineering

Caterpillar: Engine Research &Advanced Materials Technology 16

Potential for Lean-NOx Catalysis Technology - Continue

Issues/Challenges

• Higher performance catalyst

• Broader temperature window

• Higher durability

• Higher selectivity $ Lower fuel penalty

Pathway

! Leverage expertise from strategic partnerships.

! System engineering of applications.

- Integrate with developing engine combustion concepts.

Caterpillar

Universities

Suppliers

National Labs

Supported by DOE

Strategic Partnerships

Caterpillar: Engine Research &Advanced Materials Technology 17

Acknowledgements

DOE: John Fairbanks

Sidney Diamond

Gurpreet Singh

D. Ray Johnson (ORNL)

Northwestern U : Prof. H. Kung & M. Kung (DRIFT)

PNNL (EMSL): Mark Engelhard (XPS)

U of Illinois (CMM) : Wen Jianguo (TEM)