Methanol mole fraction data pertaining to the effect of porosity on the steam-methanol reforming process in microchannel reactors
Description
The methanol mole fraction data are obtained for illustrating the effect of porosity on the steam-methanol reforming process in microchannel reactors. Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume. In gas-liquid two-phase flow, the void fraction is defined as the fraction of the flow-channel volume that is occupied by the gas phase or, alternatively, as the fraction of the cross-sectional area of the channel that is occupied by the gas phase. The autothermal reactor is configured for simultaneous oxidation and steam reformation of methanol. Water steam is converted into hydrogen-rich gas using methanol in an endothermic reaction on a catalyst. The energy which is released during catalytic oxidation is necessary for the endothermic steam reformation taking place simultaneously. Methanol is combusted catalytically with air, and the heat released is used to heat the reactor. There is even less need for mass and volume storage capacity, since the same alcohol fuel is used for the endothermic and exothermic processes. An array of channels operating in parallel is used, and the inside of the channels is coated. All channels are of the same cross-section and length. Additionally, there are equal numbers of oxidation and reforming channels, which are arranged in an alternating pattern. The wall of each channel is composed of a substrate coated with a catalyst. The substrate is preferably metal, and most preferably stainless-steel sheet. To facilitate computational modeling of transport phenomena and chemical kinetics in the flowing system of complex chemical reactions involving gas-phase and surface species, steady-state analyses are performed and computational fluid dynamics is used. ANSYS FLUENT handles thermodynamic properties, transport properties, and chemical kinetics. The contribution of homogeneous chemical reactions involving gas-phase species is insignificant under the conditions of interest. The boundary conditions relate macroscopic fluid flow at a catalytically active surface to the rates of surface reactions. Heterogeneous reactions at a catalytically active surface affect the heat and mass balance at the surface. In addition, surface reactions create sources and sinks of chemical species on the surface and in the gas phase. Consequently, chemical reactions involving surface species significantly influence the boundary conditions. The mass fluxes of gas-phase species at the phase boundaries are balanced by the production rates of gas-phase species by surface reactions. 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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Steps to reproduce
The porous media model is applied to the computational domains of the catalytically active layers. The porous media involve surface reactions. ANSYS FLUENT is applied to define the terms in the equations relating to conservation, thermodynamics, chemical production rates, and equation of state, and then combine the results to define the problem involving surface chemistry.