Mean fluid temperature data pertaining to the effect of porosity on the methanol steam reforming and decomposition processes in microchannel reactors
Description
The mean fluid temperature data are obtained for illustrating the effect of porosity on the methanol steam reforming and decomposition processes in microchannel reactors. The autothermal reactor is configured for simultaneous oxidation and steam reformation of methanol. The reactor system comprises two separate sets of flow channels, which are located between spaced, highly heat-conductive metal or ceramic separating walls. The medially located, bi-catalytic separating walls have different catalysts on opposed surfaces. These catalysts are selected for the particular reaction taking place in the adjacent reaction zone. The reactor provides for continuous and simultaneous reaction of two different process reaction streams in the channels defined between the walls, wherein a first process reaction stream undergoes a high temperature exothermic reaction in the first set of flow channels and a second process reaction stream undergoes an endothermic heat-consuming reaction in the second set of flow channels separated from the first set of flow channels by the heat transfer separating walls. More specifically, the reactor system includes a set of reforming channels for steam reformation of methanol and a set of oxidation channels for heating the reactor system to operating temperature. A separating wall therefore separates two adjacent reaction zones and also functions to transfer heat from the oxidation occurring at the catalyst surface in the oxidation zone directly to the reforming catalyst coated on the opposed surface. To facilitate 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 fluid mechanics is used. ANSYS FLUENT handles thermodynamic properties, transport properties, and chemical kinetics. The contribution of homogeneous 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. Chemical reactions involving surface species significantly influence the boundary conditions. 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. 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. Overall heat and mass balances are achieved and the net imbalance is less than one percent of smallest flux through the domain boundaries. The solution converges when the residuals reach the specified tolerance and overall property conservation is satisfied.