Computational study of the segmental catalysis of steam-methanol reforming in heat integrated microchannel reactors for hydrogen production

Abstract

The present study focuses upon segmentally catalyzed steam-methanol reforming processes for producing hydrogen in heat integrated microchannel reactors. Computational simulations are carried out to understand the causes of the fundamental phenomena involved in segmental catalysis and the autothermal operation. The benefits of segmental catalysis are discussed, and some aspects of heat phenomena are explained. The effects of wall thermal conductivity, flow velocity, and catalyst segment thickness are evaluated to determine how to design heat integrated reactors for specific operations by tailoring segmental catalysis approaches. To understand the importance of thermal management, the phenomena of heat in the catalyst structure are discussed in terms of anisotropic thermal conductivity and reaction heat flux. The results indicate that the benefits of segmental catalysis are surprisingly great. Segmental catalysis can be applied to greatly extend the operation regime, and the segmented oxidation design offers distinct advantages. The segmented design may offer improvements in heat and mass transport but presents thermal management challenges caused by the rapidly varying concentrations and temperatures. The wall thermal conductivity is vital in achieving heat balance and high process efficiency. Transverse wall heat conduction is of especially critical importance in thermal management. The flow velocity and catalyst segment thickness are of great importance to the improvement of conversion and productivity. An optimum flow velocity for highest overall performance exists.