Advanced Metal-Oxide based SCR Catalysts€¦ · Advanced Metal-Oxide based SCR Catalysts Author: K. Adelmann Subject: SCR with ammonia as reductant is an effective strategy being

Advanced Metal-Oxide based SCR CatalystsUmicore AG & Co.KGK. Adelmann, N. Soeger, T. Pauly

IntroductionCurrent stage in the development of SCR catalystsMetal-oxide based SCR catalysts

NO-SCR activity & aging stabilityNH3 storage capacityHC resistanceStart-up behaviour

Summary

Agenda

Introduction

2010 DEER Conference 4

NH3-SCR – Basic Reactions

SCR-Reactions:4 NH3 + 4 NO + O2 4 N2 + 6 H2O Standard SCR

4 NH3 + 2 NO + 2 NO2 4 N2 + 6 H2O Fast SCR

NO

DOCNO2 + NO

Urea

SCR

H2O + N2

NH2 NH2

ONH3 +

HN C O

HN C O CO2NH3 +H2O +

NH3 from Urea:

1) thermal decomposition ofurea to Isocyanic Acid

2) catalytic hydrolysis of Isocyanic Acid to NH3

Current StatusFrom V-based to Zeolite-basedCatalysts

2010 DEER Conference 6

NOx Conversion of State-of-the-art SCR Families

Fe-SCR – 16h/750 CCu-SCR – 16h/750 CV-SCR – 16h/600 C

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

NO

x-co

nver

sion

[%]

Fe-SCR – 16h/750 CCu-SCR – 16h/750 CV-SCR – 16h/600 C

Metal-Oxide based SCR Catalysts

2010 DEER Conference 8

NOx Conversion compared to Fe-zeolite

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

NO

x-co

nver

sion

[%]

Fe-SCR – 16h/750 CMO-SCR – 16h/750 C

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

N2O

con

cent

ratio

n [p

pm]

Fe-SCR – 16h/750 CMO-SCR – 16h/750 C

2010 DEER Conference 9

NOx Conversion compared to Cu-zeolite

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

Cu-SCR – 16h/750 CMO-SCR – 16h/750 C

NO

x-co

nver

sion

[%]

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

N2O

con

cent

ratio

n [p

pm]

Cu-SCR – 16h/750 CMO-SCR – 16h/750 C

2010 DEER Conference 10

Impact of NO/NO2 Ratio

0

20

40

60

80

100

120

0 20 40 60 80

NO2 [%]

NO

x co

nver

sion

[%]

350°C250°C200°C175°C

2010 DEER Conference 11

MO-SCR – Aging Influence

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

MO-SCR – Fresh MO-SCR – 200h/600 CMO-SCR – 48h/650 CMO-SCR – 16 h/750 C

NO

x-co

nver

sion

[%]

2010 DEER Conference 12

200°C

0

20

40

60

80

100

Fe-SCR MO-SCR

NO

con

vers

ion

[%]

fresh200h/600°C48h/650°C16h/750°C

Aging Stability compared to Fe-zeolite

Very high aging stability compared to Fe-zeolite

250°C

0

20

40

60

80

100

Fe-SCR MO-SCR

NO

con

vers

ion

[%]

fresh200h/600°C48h/650°C16h/750°C

2010 DEER Conference 13

NH3 Storage Capacity

Target:

stable NH3 storage

a) over temperature

b) over aging

0

500

1000

1500

2000

2500

150 200 250 300 350 400 450T [°C]

m N

H3 [

mg/

L C

at]

Fe-SCR - fresh

Fe-SCR - 16h/750°C

MO-SCR - fresh

MO-SCR - 16h/750°C

2010 DEER Conference 14

NH3 Storage Capacity

Target:

stable NH3 storage

a) over temperature

b) over aging

0

500

1000

1500

2000

2500

150 200 250 300 350 400 450T [°C]

m N

H3 [

mg/

L C

at]

Fe-SCR - freshFe-SCR - 16h/750°CMO-SCR - freshMO-SCR - 16h/750°CCu-SCR - freshCu-SCR - 16h/750°C

2010 DEER Conference 15

Impact of HC/CO – Exotherm Generation

Risk:

Thermal damage by exotherm generation e.g. over acceleration phase after HC storage

0

100

200

300

400

500

600

700

800

900

600 620 640 660 680 700time (s)

T [°

C]

T in front of catalystFe-SCRCu-SCRMO-SCR

2010 DEER Conference 16

Influence of HC/CO

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

MO-SCR – 16h/750 CMO-SCR – 16h/750 C w/- HC/CO

NO

x-co

nver

sion

[%]

100 150 200 250 300 350 400 450 500 550T [ C]

0

10

20

30

40

50

60

70

80

90

100

NO

x-co

nver

sion

[%]

Fe-SCR – 16h/750 CFe-SCR – 16h/750 C w/- HC/CO

2010 DEER Conference 17

Dynamic Start-up

High dynamic start-up compared to Fe-SCR

Fast NH3 break-through in case of overdosing

MO-SCR - 250°C

0

20

40

60

80

100

0 50 100 150 200time [s]

NO

x-co

nver

sion

[%]

0

100

200

300

400

500

c [p

pm]

NOx-conversion [%] c NH3 [ppm]

Fe-SCR - 250°C

0

20

40

60

80

100

0 50 100 150 200time [s]

NO

x-co

nver

sion

[%]

0

100

200

300

400

500

c [p

pm]

NOx-conversion [%] c NH3 [ppm]

2010 DEER Conference 18

Dynamic Start-up

High dynamic start-up compared to Cu-SCR

Fast NH3 break-through in case of overdosing

MO-SCR - 250°C

0

20

40

60

80

100

0 50 100 150 200time [s]

NO

x-co

nver

sion

[%]

0

100

200

300

400

500

c [p

pm]

NOx-conversion [%] c NH3 [ppm]

Cu-SCR - 250°C

0

20

40

60

80

100

0 50 100 150 200

time [s]

NO

x-co

nver

sion

[%]

0

100

200

300

400

500

c [p

pm]

NOx-conversion [%] c NH3 [ppm]

2010 DEER Conference 19

NOx Conversion vs. Amount of NH3 dosed

0

10

20

30

40

50

60

70

80

90

100

0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004

Amount of NH3 dosed [mol]

NO

x con

vers

ion

[%]

Cu-SCR Fe-SCR MO-SCR

Summary

2010 DEER Conference 21

Characteristics of Metal-Oxide based SCR Catalysts Improved low temperature performance compared to Fe-

zeolites No significant N2O formation High aging stability Stable NH3 storage over temperature & over aging High tolerance towards hydrocarbon, no risk of exotherm

generation High dynamic start-up behaviour

Thank you!