H₂ and CO Heterogeneous Kinetic Coupling during Combustion of H₂/CO/O₂/N₂ Mixtures over Rhodium

Ran Sui; John Mantzaras; Rolf Bombach

doi:10.1016/j.combustflame.2019.01.021

H₂ and CO Heterogeneous Kinetic Coupling during Combustion of H₂/CO/O₂/N₂ Mixtures over Rhodium

Ran Sui
, John Mantzaras
, Rolf Bombach

Missouri University of Science and Technology

Research output: Contribution to journal › Article › peer-review

Abstract

The chemical interactions between CO and H ₂ over rhodium were investigated for H ₂ /CO/O ₂ /N ₂ mixtures with H ₂ :CO volumetric ratios 1:5-3:1, overall fuel-lean equivalence ratios φ = 0.13 and 0.23, a pressure of 5 bar, and surface temperatures 510-610 K. This temperature range was particularly important for catalytic ignition in hybrid hetero-/homogeneous combustion concepts of large gas-turbines operating at part-load or idling conditions and in recuperative micro-turbine-based microreactors at normal operation. In situ Raman measurements of major gas-phase species concentrations were carried out over the catalyst boundary layer, while 2-D simulations were performed with a detailed catalytic reaction scheme. Comparisons of simulations and measurements assessed the performance of the catalytic reaction mechanism for the oxidation of pure CO, pure H ₂ and H ₂ /CO fuel blends. Transition temperatures were identified below (above) which H ₂ inhibited (promoted) the oxidation of CO. For a given equivalence ratio, the transition temperatures decreased significantly with increasing H ₂ :CO volumetric ratio (595 K for H ₂ :CO = 1:5 and less than 535 K for H ₂ :CO = 3:1, at φ = 0.13) while for a given H ₂ :CO volumetric ratio they dropped moderately with decreasing φ. This behavior was fundamentally different to that of platinum catalysts, whereby transition temperatures depended weakly on H ₂ :CO volumetric ratio and stronger on equivalence ratio. The strong dependence of the transition temperatures on H ₂ :CO volumetric ratio over rhodium pointed to the advantage of this catalyst when used for high-hydrogen-content ( > 80% volume) fuels in power generation applications. The promotion effect of H ₂ on CO oxidation above the transition temperatures was a result of the increased importance of the indirect CO oxidation route via surface COOH.

Original language	American English
Journal	Combustion and Flame
Volume	202
DOIs	https://doi.org/10.1016/j.combustflame.2019.01.021
State	Published - Apr 1 2019

Keywords

Chemical interactions of H2 and CO over rhodium
In situ Raman measurements
Inhibition of CO oxidation by H2
Syngas catalytic combustion for power generation
Transition temperatures

Disciplines

Mechanical Engineering

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https://doi.org/10.1016/j.combustflame.2019.01.021

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@article{836881ab9acf4b89843392cd3f2e2187,

title = "H₂ and CO Heterogeneous Kinetic Coupling during Combustion of H₂/CO/O₂/N₂ Mixtures over Rhodium",

abstract = " The chemical interactions between CO and H 2 over rhodium were investigated for H 2 /CO/O 2 /N 2 mixtures with H 2 :CO volumetric ratios 1:5-3:1, overall fuel-lean equivalence ratios φ = 0.13 and 0.23, a pressure of 5 bar, and surface temperatures 510-610 K. This temperature range was particularly important for catalytic ignition in hybrid hetero-/homogeneous combustion concepts of large gas-turbines operating at part-load or idling conditions and in recuperative micro-turbine-based microreactors at normal operation. In situ Raman measurements of major gas-phase species concentrations were carried out over the catalyst boundary layer, while 2-D simulations were performed with a detailed catalytic reaction scheme. Comparisons of simulations and measurements assessed the performance of the catalytic reaction mechanism for the oxidation of pure CO, pure H 2 and H 2 /CO fuel blends. Transition temperatures were identified below (above) which H 2 inhibited (promoted) the oxidation of CO. For a given equivalence ratio, the transition temperatures decreased significantly with increasing H 2 :CO volumetric ratio (595 K for H 2 :CO = 1:5 and less than 535 K for H 2 :CO = 3:1, at φ = 0.13) while for a given H 2 :CO volumetric ratio they dropped moderately with decreasing φ. This behavior was fundamentally different to that of platinum catalysts, whereby transition temperatures depended weakly on H 2 :CO volumetric ratio and stronger on equivalence ratio. The strong dependence of the transition temperatures on H 2 :CO volumetric ratio over rhodium pointed to the advantage of this catalyst when used for high-hydrogen-content ( > 80\% volume) fuels in power generation applications. The promotion effect of H 2 on CO oxidation above the transition temperatures was a result of the increased importance of the indirect CO oxidation route via surface COOH.",

keywords = "Chemical interactions of H2 and CO over rhodium, In situ Raman measurements, Inhibition of CO oxidation by H2, Syngas catalytic combustion for power generation, Transition temperatures",

author = "Ran Sui and John Mantzaras and Rolf Bombach",

year = "2019",

month = apr,

day = "1",

doi = "10.1016/j.combustflame.2019.01.021",

language = "American English",

volume = "202",

journal = "Combustion and Flame",

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TY - JOUR

T1 - H₂ and CO Heterogeneous Kinetic Coupling during Combustion of H₂/CO/O₂/N₂ Mixtures over Rhodium

AU - Sui, Ran

AU - Mantzaras, John

AU - Bombach, Rolf

PY - 2019/4/1

Y1 - 2019/4/1

N2 - The chemical interactions between CO and H 2 over rhodium were investigated for H 2 /CO/O 2 /N 2 mixtures with H 2 :CO volumetric ratios 1:5-3:1, overall fuel-lean equivalence ratios φ = 0.13 and 0.23, a pressure of 5 bar, and surface temperatures 510-610 K. This temperature range was particularly important for catalytic ignition in hybrid hetero-/homogeneous combustion concepts of large gas-turbines operating at part-load or idling conditions and in recuperative micro-turbine-based microreactors at normal operation. In situ Raman measurements of major gas-phase species concentrations were carried out over the catalyst boundary layer, while 2-D simulations were performed with a detailed catalytic reaction scheme. Comparisons of simulations and measurements assessed the performance of the catalytic reaction mechanism for the oxidation of pure CO, pure H 2 and H 2 /CO fuel blends. Transition temperatures were identified below (above) which H 2 inhibited (promoted) the oxidation of CO. For a given equivalence ratio, the transition temperatures decreased significantly with increasing H 2 :CO volumetric ratio (595 K for H 2 :CO = 1:5 and less than 535 K for H 2 :CO = 3:1, at φ = 0.13) while for a given H 2 :CO volumetric ratio they dropped moderately with decreasing φ. This behavior was fundamentally different to that of platinum catalysts, whereby transition temperatures depended weakly on H 2 :CO volumetric ratio and stronger on equivalence ratio. The strong dependence of the transition temperatures on H 2 :CO volumetric ratio over rhodium pointed to the advantage of this catalyst when used for high-hydrogen-content ( > 80% volume) fuels in power generation applications. The promotion effect of H 2 on CO oxidation above the transition temperatures was a result of the increased importance of the indirect CO oxidation route via surface COOH.

AB - The chemical interactions between CO and H 2 over rhodium were investigated for H 2 /CO/O 2 /N 2 mixtures with H 2 :CO volumetric ratios 1:5-3:1, overall fuel-lean equivalence ratios φ = 0.13 and 0.23, a pressure of 5 bar, and surface temperatures 510-610 K. This temperature range was particularly important for catalytic ignition in hybrid hetero-/homogeneous combustion concepts of large gas-turbines operating at part-load or idling conditions and in recuperative micro-turbine-based microreactors at normal operation. In situ Raman measurements of major gas-phase species concentrations were carried out over the catalyst boundary layer, while 2-D simulations were performed with a detailed catalytic reaction scheme. Comparisons of simulations and measurements assessed the performance of the catalytic reaction mechanism for the oxidation of pure CO, pure H 2 and H 2 /CO fuel blends. Transition temperatures were identified below (above) which H 2 inhibited (promoted) the oxidation of CO. For a given equivalence ratio, the transition temperatures decreased significantly with increasing H 2 :CO volumetric ratio (595 K for H 2 :CO = 1:5 and less than 535 K for H 2 :CO = 3:1, at φ = 0.13) while for a given H 2 :CO volumetric ratio they dropped moderately with decreasing φ. This behavior was fundamentally different to that of platinum catalysts, whereby transition temperatures depended weakly on H 2 :CO volumetric ratio and stronger on equivalence ratio. The strong dependence of the transition temperatures on H 2 :CO volumetric ratio over rhodium pointed to the advantage of this catalyst when used for high-hydrogen-content ( > 80% volume) fuels in power generation applications. The promotion effect of H 2 on CO oxidation above the transition temperatures was a result of the increased importance of the indirect CO oxidation route via surface COOH.

KW - Chemical interactions of H2 and CO over rhodium

KW - In situ Raman measurements

KW - Inhibition of CO oxidation by H2

KW - Syngas catalytic combustion for power generation

KW - Transition temperatures

UR - https://scholarsmine.mst.edu/mec_aereng_facwork/4579

UR - https://doi.org/10.1016/j.combustflame.2019.01.021

U2 - 10.1016/j.combustflame.2019.01.021

DO - 10.1016/j.combustflame.2019.01.021

M3 - Article

VL - 202

JO - Combustion and Flame

JF - Combustion and Flame

ER -

H₂ and CO Heterogeneous Kinetic Coupling during Combustion of H₂/CO/O₂/N₂ Mixtures over Rhodium

Abstract

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