Microreactor catalytic combustion for chemicals processing

Comparison is drawn between two small reactor systems in the context of production of methanol from synthesis gas (syngas) and of ethylene by the non-oxidative dehydrogenation of ethane using computer-based modelling techniques. The production of methanol requires syngas containing hydrogen and carbon monoxide at controlled temperatures. The supply of syngas from a combination of steam reforming and catalytic combustion of methane was modelled for a parallel microchannel array and for a cascade reactor system in which reaction occurs in a series of beds, heat exchange in interconnecting microchannel heat exchangers being used to maintain the desired temperature. Although conversion was slightly higher in the microchannel systems, the advantages of better temperature control and easy replacement of deactivated catalyst favoured the cascade array. The use of the two reactor systems was also modelled for the ethane dehydrogenation, a reaction in which temperature control is essential to minimise coking. In this case catalytic combustion of methane provided direct heat to the dehydrogenation chamber. Again the microchannels gave slightly better conversion but temperature control was superior in the cascade system. The size of equipment needed to produce unit amount of product was smaller for the cascade systems in both cases, favouring their use for remote location operations. (C) 2009 Elsevier B.V. All rights reserved.