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  • 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!

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