Catalytic oxidation process data pertaining to microchannel steam reforming reactors under different porosity conditions
Description
The catalytic oxidation process data are obtained for microchannel steam reforming reactors under different porosity conditions. The reforming process proceeds in one set of the channels through which the endothermic reactants flow, and the exothermic oxidation process proceeds in the second set of the channels. Exothermic and endothermic reactions take place simultaneously whereby the heat required for the latter is supplied by the former. Heat transfer occurs via conduction through the walls of the reactor. For the endothermic reaction, the structure is especially effective because both the internal surfaces of the walls are coated with structured catalysts, which is capable of providing more efficient heat exchange. Only two half oxidation and reforming channels as well as the surrounding walls are modeled due to the symmetry of the structurally integral system. The ratio of the height of the channels to the width of the channels may vary. The cross-sectional configuration of the channels is square. The channels are 0.7 millimeters in height and in width and 30.0 millimeters in length. Channel height refers to the inside height of a channel. The oxidation catalyst consists essentially of oxides of copper, zinc and aluminum. The oxidation catalyst allows for initial start-up and the heat-up of the reactor system. The reforming catalyst consists essentially of copper and oxides of zinc and aluminum. These catalysts are selected for the particular reaction taking place in the adjacent reaction zone. The temperature of the reactor can be regulated by the balance of the flow rates so that the catalyst is not overheated by the exothermic process and thus damaged. To assure that adequate temperatures are provided for endothermic reforming, operating flow conditions are specified for the reactor by giving the gas velocity. The gas velocity is 2.0 meters per second at the reforming channel inlets and 0.6 meters per second at the oxidation channel inlets, thereby assuring sufficient heat in the reactor. The reactor system is operated using excess air and water steam. Methanol and air are mixed homogeneously and the mixture is fed directly into the oxidation channels in a specific ratio. To facilitate computational modeling of transport phenomena and chemical kinetics in the flowing system of complex chemical reactions, steady-state analyses are performed and fluid mechanics is used. The Reynolds numbers are very small so that the gases flow through the channels in a laminar flow regime. The endothermic process is modeled in such a way as to take into account methanol steam reforming and decomposition and the water-gas shift reaction. Contributor: Junjie Chen, E-mail address: koncjj@gmail.com, ORCID: 0000-0002-5022-6863, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China
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ANSYS FLUENT is applied to the problem involving surface chemistry. ANSYS FLUENT handles thermodynamic properties, transport properties, gas-phase equation-of-state, and chemical kinetics. A piecewise-polynomial function is specified for the temperature dependence. To define composition-dependent properties for the mixtures, the mass-weighted-mixing-law is applied.