Minimizing Heat Transfer Resistance in an Integrated Methanol Steam Reformer Designed Using Space-Filling Curves

Abstract

Conventional packed bed methanol steam reformers producing hydrogen for PEM fuel cells have an inherent trade-off problem between simultaneously attaining high methanol conversion and low carbon monoxide production, owing to high thermal resistance in the packed bed. A sophisticated reformer design using Hilbert’s space-filling curves is proposed and demonstrated using CFD modeling and simulation. The reactor comprises a flow-through domain divided into two interdigitating but nonmixing continua that are separated by a thin wall, providing high interfacial area for heat transfer and surface reactions. The interfacial wall is modeled as coated with catalyst for performing reforming on one side and fuel cell anode exhaust hydrogen combustion on the other side. About 84% methanol conversion and CO production less than 2% was achieved due to remarkable reduction in heat transfer resistance. External mass transfer controlled the reactor operation, while reaction kinetics exhibited nontrivial influence on reactor performance.