Methanol mole fraction contour plots for heterogeneously catalyzed steam reforming reactors with different flow channel shapes
Description
The methanol mole fraction contour plots are presented from a heterogeneously catalyzed steam reforming reactor, which can simultaneously carry out exothermic and endothermic reactions in separate flow channels and simultaneously adjust feed composition and flow rates. To obtain the solution of the problem, numerical simulations are performed using fluid mechanics. Theoretically, the flow channels can be of any shape. The flow channels can be shaped into any of various configurations, but they must be designed to increase the area available for heat exchange, thereby minimizing the length of the channels and the associated pressure drop. The flow channels form a variety of cross-sectional shapes ranging from square to ellipse. Corners of the flow channels can be rounded off. Specifically, the cross-sectional shape of the flow channels is defined as follows: an ellipse within a circle, a circle within a larger circle, fillets formed in the corners of a square, a circle within a square, and a square within a larger square. The cross-sectional shape of the flow channels can be defined by means of a number of geometric parameters. A methanol-steam mixture is supplied to the reforming channels to be reformed, and a methanol-air mixture is supplied to the combustion channels to be combusted. The temperatures and pressures of the two streams entering the combustion channels and the reforming channels, respectively, are the same. The temperature of the two streams is 373 degrees Kelvin at the flow inlets. The system operates at a pressure of up to 1.5 megapascals. Typically, high pressure combustion is widely practiced. Although a stoichiometric ratio of fuel to air is sufficient, an equivalence ratio of 0.8 is employed. A steam-to-carbon molar ratio of 1.4 is employed. The fluids flow essentially parallel to the axes of the channels. The velocity of the fluid flowing into the reforming channels is 2.0 meters per second at the flow inlets. In contrast, the velocity of the fluid flowing into the combustion channels varies depending on the desired design requirements. 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 governing equations are discretized in space, and the second-order upwind discretization scheme is used. 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, gas-phase equation-of-state, and chemical kinetics. The boundary conditions relate macroscopic fluid flow at a catalytically active surface to the rates of surface reactions. 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.