Performance analysis of methanol steam micro-reformers for enhanced hydrogen production using CFD

Abstract

Present study shows the performance analysis of methanol steam reforming considering different miniature-scale reformer geometries. Three different types of 3D models of steam reformers have been considered: straight annular, spiral, and serpentine-type reactors. Each reformer is packed with a copper-based catalyst to enhance the reaction between steam and methanol. Methanol steam reforming is an endothermic reaction with a two-step mechanism, whose reaction kinetic models were mathematically implemented. The study shows different hydrodynamic aspects of the flow fields through the catalyst bed, the conversion of methanol, and production of hydrogen for each type of reactors. Simulations were carried out at different temperatures and inlet velocities to study the methanol conversion and identify the most optimized reformer design. It was found that in the spiral and serpentine-type reformer, the methanol conversion was more due to the bending in the tubular reactor, which disturbs the flow field with an enhancement of mixing, causing more conversion. Spiral reformer exhibited conversion up to 91.16% at 650 K and producing 0.15 mass fraction of hydrogen, which was found to be 3% more than the conversion achieved in serpentine type and almost 8% more than the straight annular type geometry when the inlet velocity was kept at 0.1 m/s for all the cases.