Investigation of catalyst performance and microstructured reactor configuration for syngas production by methane steam reforming

This work involves comparative investigation of two catalytic microchannel configurations for synthesis gas generation by methane steam reforming. In the first configuration, catalyst is in the form of a layer which is coated onto the microchannel wall, while the second one is defined by the packing of particulate catalyst into an empty microchannel of the same dimension. Comparison between these geometries is carried out for four different catalysts – Rh, Ru, Pd, Ni – all of which are supported on alumina, and involves testing of different reaction temperatures (873, 923, 973, 1023 K) and steam-to-carbon ratios (2.5, 3.0, 3.5) for each catalyst through a parametric approach. Compared with the packed version, wall-coated microchannel geometry leads to higher methane conversions and syngas production rates as well as lower H2/CO ratios in the entire parameter and catalyst range investigated. Rh is the best catalyst in terms of activity and H2 and CO throughputs, while Ni gives the highest hydrogen selectivity. The results indicate the possibility of reducing H2/CO ratio in methane steam reforming by the use of reformers characterized by wall-coated microchannels.

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► At 873–1023 K and S/C = 2.5–3.5, methane steam reforming performances of coated microchannels are much higher than packed microchannels.
► H2/CO molar ratios in the product are significantly lower in coated microchannels.
► Catalyst activities for both coated and packed microchannels decrease as Rh > Pd≥ Ni > Ru.
► H2 and CO production rates and CO selectivity on Rh are the highest, while Ni gives highest H2 selectivity.