Carbon dioxide mole fraction data under different porosity conditions pertaining to the steam reforming process in micro-structured heterogeneous reaction systems
Description
The carbon dioxide mole fraction data under different porosity conditions are obtained for illustrating the steam reforming process in micro-structured heterogeneous reaction systems. Specifically, the present mole fraction data are directed to a parallel reaction system, which can simultaneously carry out exothermic and endothermic reactions in separate micro-channels and simultaneously adjust feed composition and flow rates. 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. 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. Additionally, there are equal numbers of oxidation and reforming channels, which are arranged in an alternating pattern. 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. The forward rate constant of a surface reaction as a function of thermodynamic temperature is given by the modified Arrhenius expression. The reverse rate constant of the surface reaction involved in reaching equilibrium is related to the forward rate constant through the equilibrium constant. The equilibrium constant is given in concentration units. The energy released or consumed at each phase boundary is obtained using a summation over all gas-phase species. The surface area factor is defined in terms of geometric and catalyst surface area. Geometric surface area is the macroscopic surface area of a substrate that holds or supports a catalyst in a reactor. Geometric surface area does not include the additional surface area contributed by generally microscopic or small surface roughness or porosity. Catalyst surface area refers to the surface area of the kinetically active substance in a catalytic reactor. Catalyst specific surface area is defined as the catalyst specific surface area divided by the volume of the substrate that holds or supports a catalyst in a reactor. The porosity is isotropic. The porosity does not vary with space and therefore the porous media are homogeneous. 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, equation-of-state, and chemical kinetics. Physical properties depend on temperature and composition. Overall heat and mass balances are achieved and the net imbalance is less than one percent of smallest flux through the domain boundaries.