Mass transfer effects in stagnation flows on a porous catalyst: Water-gas-shift reaction over Rh/Al2O3

Hüseyin Karadeniz; Canan Karakaya; Steffen Tischer; Olaf Deutschmann

doi:10.1515/zpch-2014-0622

Mass transfer effects in stagnation flows on a porous catalyst: Water-gas-shift reaction over Rh/Al₂O₃

Hüseyin Karadeniz, Canan Karakaya, Steffen Tischer, Olaf Deutschmann

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

14 Scopus citations

Abstract

Water-gas-shift (WGS) and reverse water-gas-shift (RWGS) reactions are numerically investigated in a stagnation-flow on a porous Rh/Al₂O₃ catalyst. External and internal mass transfer effects are studied using three different models for the mass transport and chemical conversion inside the porous catalyst: the dusty-gas model, a set of reaction-diffusion equations, and the effectiveness factor approach. All three models are coupled with the boundary layer equations to describe the potential flow on the stagnation disc, and a multi-step surface reaction mechanism is implemented. The numerically predicted species profiles in the external boundary layer are compared with recently measured profiles. Internal mass transfer limitations are more significant than external ones in case of the 100 μm thick catalyst layer. The effects of catalyst structure (thickness, mean pore diameter, porosity, tortuosity) as well as flow rate and pressure on chemical conversion are discussed.

Original language	English
Pages (from-to)	709-737
Number of pages	29
Journal	Zeitschrift fur Physikalische Chemie
Volume	229
Issue number	5
DOIs	https://doi.org/10.1515/zpch-2014-0622
State	Published - May 28 2015
Externally published	Yes

Funding

Acknowledgement: We appreciate helpful discussions with R. J. Kee and H. Zhu from Colorado School of Mines on stagnation-flow reactor modelling. Financial support by the Steinbeis GmbH and the Deutsche Forschungsgemeinschaft (DFG) are gratefully acknowledged.

Keywords

Dusty-Gas Model
External and Internal Mass Transfer
Reaction-Diffusion
Reverse Water-Gas-Shift
Rhodium
Stagnation-Flow
Water-Gas-Shift Reaction

Access to Document

10.1515/zpch-2014-0622

Cite this

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title = "Mass transfer effects in stagnation flows on a porous catalyst: Water-gas-shift reaction over Rh/Al2O3",

abstract = "Water-gas-shift (WGS) and reverse water-gas-shift (RWGS) reactions are numerically investigated in a stagnation-flow on a porous Rh/Al2O3 catalyst. External and internal mass transfer effects are studied using three different models for the mass transport and chemical conversion inside the porous catalyst: the dusty-gas model, a set of reaction-diffusion equations, and the effectiveness factor approach. All three models are coupled with the boundary layer equations to describe the potential flow on the stagnation disc, and a multi-step surface reaction mechanism is implemented. The numerically predicted species profiles in the external boundary layer are compared with recently measured profiles. Internal mass transfer limitations are more significant than external ones in case of the 100 μm thick catalyst layer. The effects of catalyst structure (thickness, mean pore diameter, porosity, tortuosity) as well as flow rate and pressure on chemical conversion are discussed.",

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