A structured test reactor for the evaporation of methanol on the basis of a catalytic combustion

详细信息    查看全文

• 作者：Pasel ; Joachim ; Emonts ; Bernd ; Peters ; Ralf ; Stolten ; Detlef
• 关键词：Methanol ; Catalytic deep oxidation ; Noble metals ; Structured reactor ; Ignition ; Kinetics ; Diffusion limitation
• 刊名：Catalysis Today
• 出版年：2001
• 出版时间：September 15, 2001
• 年：2001
• 卷：69
• 期：1-4
• 页码：193-200
• 全文大小：215 K

文摘

The kinetics of the catalytic deep oxidation of methanol was studied in stacked segments of a turbulence insert (SSTIs) coated with Pt/γ-Al₂O₃ and Pt/zeolite catalysts. These geometries, which are termed a structured test reactor in the heading, are intended to replace plane expanded metal discs (PEMDs) used in the so-called catalytic burner at Research Centre Jülich, up to the present. The catalytic burner performs the low-pollution combustion inter alia of the anode exhaust gases of the fuel cell. SSTIs coated with Pt/γ-Al₂O₃ showed different kinetics for differential conversions as a function of temperature. At low reaction temperatures (100–130°C) ignition kinetics with a very high activation energy of 60.3kJ/mol was found. In the further course of the reaction, the kinetically controlled reaction with an activation energy of 48.5kJ/mol was observed. In the range of non-differential conversions, the activation energy decreased significantly, which suggests a limitation of the reaction process by mass transport phenomena. Compared to the PEMDs, clearly higher reaction rates were observed, which enable a reduction of the catalyst mass. This as well as the spatial structure of the SSTIs make it possible to achieve a reduction in volume and weight and thus improved dynamics in constructing a novel catalytic burner. The SSTIs coated with Pt/zeolite showed perceptibly lower reaction rates than the Pt/γ-Al₂O₃ substrates and could thus not compete with the PEMDs.