Modelling catalytic combustion of carbon monoxide and hydrocarbons over catalytically active wire meshes

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 73; no. 3; pp. 205 - 216
• Main Authors: Fredrik Ahlström-Silversand, Anders, Ulf Ingemar Odenbrand, Claes
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1999; Elsevier
• Subjects: Catalysis; Catalysts: preparations and properties; Catalytic combustion; Chemical Engineering; Chemistry; Engineering and Technology; Exact sciences and technology; General and physical chemistry; Kemiteknik; Modelling; Monolith; Pellets; Teknik; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Thermal spraying; Wire mesh; Thermal spraying; Modelling; Catalytic combustion; Wire mesh; Monolith; Pellets; Conversion rate; Supported catalyst; Characterization; Platinum; Carbon monoxide; Plasma spraying; Platinoid; Hydrocarbon; Hydrodynamics; Transition metal; Palladium; Experimental study; Mass transfer; Heterogeneous catalysis; Impregnation; Propene; Terpene; Pressure drop; Preparation; Numerical simulation; Kinetics; Performance; Alumina; Ethylenic compound; Heat transfer
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/S1385-8947(99)00029-7

A new way of preparing catalytically active wire meshes through a thermal-spray technique is described. A metal substrate (e.g. Kanthal AF) was plasma-sprayed with a composite ceramic/polymer-powder. The polymer content of the sprayed layer was burnt off whereupon a well-defined macro-porosity was created. By treating the so obtained material with an alumina-sol the specific surface area could be increased by a factor of 50 or more. The ceramic layer was finally activated with precious metals through an impregnation step. A numerical model was developed to compare the performance of wire-mesh-, monolith- and pellets catalysts. The model describes the resistance to internal and external mass- and heat transfer and the effects of axial dispersion. The wire-mesh model was verified through experiments. Different evaluation parameters were derived to compare the catalyst performance relative to the catalyst volume, the geometric weight, the catalyst weight, the pressure drop and the temperature response. Wire-mesh catalysts offer the following advantages: high mass and heat transfer numbers, moderate pressure drop, insignificant effects of pore diffusion and axial dispersion, thermal and mechanical strength, geometric flexibility, excellent thermal response, simplicity in the catalyst recovery. The cost of a wire-mesh catalyst is expected to be competitive to other alternatives.