Model development for microchannel reactor systems for the production of hydrogen by methanol steam reforming

The present study is directed to the model development for a parallel reaction system, especially a chemical processing micro-system, which can simultaneously carry out exothermic and endothermic reactions in separate micro-channels and simultaneously adjust feed composition and flow rates. Specifically, the present study relates to the model development for a catalytic process of steam-methanol reforming for the production of hydrogen in a microchannel heterogeneous reaction system. Computational fluid dynamics simulations are performed with respect to various factors pertaining to microchannel reactor systems. Steady-state analyses are carried out to investigate the effects of various key parameters on processes such as chemical reactions or heat and mass transfer in the system. 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 boundary conditions relate macroscopic fluid flow at a catalytically active surface to the rates of surface reactions. 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. The heat release and consumption due to a surface reaction must be included in the model. Endothermicity or exothermicity of surface reactions contribute to the energy balance at an interface. Heat fluxes in the solid phase are balanced by chemical heat release at the surface. The porous media model is applied to the computational domains of the catalytically active layers. The porous media involve surface reactions. Each porous medium is modeled by adding a momentum source term to the standard momentum conservation equations and by the modification of a heat conduction flux term to the standard gas phase energy balance equation. The predictions are in satisfactory agreement with the data obtained from experimental measurements.

Contributor: Junjie Chen, ORCID: 0000-0002-5022-6863, E-mail address: koncjj@gmail.com, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China

Declaration of competing interest: The authors declare that there is no conflict of interest.