Performance test of a bench-scale multi-tubular membrane reformer

Apart from H2 production, hydrogen membrane reforming is also an attractive process for CO2 capture when integrated in a natural gas fired power plant. In this study, a bench-scale multi-tubular Pd membrane reactor which has a capacity of 8.5 Nm3/h H2 product, was used to carry out the methane steam reforming reaction at near-practical working conditions: 823 K and up to 35 bar(a). The maximum CH4 conversion and H2 production rate were respectively achieved as 73.4% and 1.3 Nm3/h at a feed/permeate pressure of 35/5 bar(a). A typical pre-reformed mixture (PR) was used as feed gas in this work, and was found to be more efficient than CH4/H2O mixture that is normally adopted in the literature. The steam sweep exhibited a similar effect as N2 sweep except at very low space velocity that revealed steam outperforming N2. Stable performance was found both for the membranes and the membrane reactor under the challenging conditions for over 30 days, showing a great potential of hydrogen membrane reforming for H2 production. However, membrane reforming is found to be less attractive for CO2 capture due to the low CH4 conversion and consequent low driving force for transmembrane hydrogen transport at the high permeate pressure typical for NGCC operation.