The dimensionless Nusselt number data at different flow rates pertaining to the oxidation catalyst segmentation methods employed for continuous flow reactors
Description
The dimensionless Nusselt number data at different flow rates are presented associated with the oxidation catalyst segmentation methods employed for continuous flow reactors. 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. Heat transfer occurs via conduction through the walls of the continuous flow 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 and minimizing the problem of loss of catalytic activity. 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. To ensure the mechanical strength at elevated pressures, the thickness of the uncoated walls and the catalyst layers is 0.7 millimeters and 0.1 millimeters, respectively. 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 continuous flow reactor system. The reforming catalyst consists essentially of copper and oxides of zinc and aluminum. The exothermic and endothermic processes are conducted at a pressure of 0.8 megapascals, with a methanol-air equivalence ratio of 0.8 and a steam-to-methanol molar ratio of 1.17. The inlet temperature of the mixtures is 373 degrees Kelvin. The temperature of the continuous flow reactor can be regulated by the balance of the flow rates so that the catalyst is not overheated by the exothermic process. To assure that adequate temperatures are provided for endothermic reforming, operating flow conditions are specified for the continuous flow reactor by giving the gas velocity. 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 each reforming channel, the catalyst layer is reduced by half in amount. The catalyst segments have a uniform distribution of length, and the spacing between catalyst segments is equal to their length. The porous media model is applied to the computational domains of the catalytically active layers. Each porous medium is modeled by the modification of a heat conduction flux term to the standard gas phase energy balance equation. 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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To describe the surface reaction mechanisms in symbolic form, the following information is required, including the thermochemical properties of surface species in the surface phases, names of the surface species, site densities, names of all surface phases, Arrhenius rate coefficients, reaction descriptions, and any optional coverage parameters.