Performance and operating limits of a sorbent-catalyst system for sorption-enhanced reforming (SER) in a fluidized bed reactor

Abstract The combined performance of a synthetic CaO-Ca 12 Al 14 O 33 sorbent and an Ni-MgAl 2 O 4 reforming catalyst was tested in a fluidized bed reactor under relevant operating conditions for the sorption-enhanced reforming (SER) process. The effect of CH 4 space velocity (i.e. kg CH4 /h·kg cat ), steam-to-carbon (S/C) ratio and superficial gas velocity on product gas composition was assessed, as well as the effect of regeneration conditions on material performance. Moreover, a bi-functional material prepared by mechanical mixing of the separate materials was also tested in the reactor under consecutive SER/regeneration cycles. H 2 contents as high as 96 vol% (N 2 free, dry basis) were achieved under SER operation, using the separated materials working with an Ni content of 3.75 wt% in the solid bed at 650 °C with S/C ratios of 3 and 4. This solid system is able to process up to 0.63 kg CH4 /h·kg cat at 0.1 m/s superficial gas velocity and with an S/C ratio of 4, although the CH 4 input has to be reduced to 0.33 kg CH4 /h·kg cat when working with a lower S/C ratio. Similar H 2 contents to those found in the separated materials were obtained with the combined sorbent-catalyst material working with 0.33 kg CH4 /h·kg cat at 0.1 m/s superficial gas velocity and S/C ratios of 3 and 4. The CO 2 sorption capacity of the combined material produced the same as that of the separate sorbent particles (i.e. around 0.25 g CO2 /g calcined sorbent), while remaining stable throughout the SER/regeneration cycles.