Kinetic modeling‐assisted design of sorption‐enhanced biomass gasification in moving beds for hydrogen production

Abstract Near‐isothermal operation in fluidized beds may limit the efficiency of sorption‐enhanced gasification (SEG). This study modeled autothermal SEG in moving beds to leverage their inherent temperature gradients to enhance reaction efficiency, comparing the downdraft, updraft, and dualdraft configurations. Results showed that the novel dualdraft gasifier achieved the highest char conversion, making it suitable for carbon‐rich fuels, while high tar yields made the updraft design unsuitable for biomass SEG. The downdraft design achieved the highest hydrogen yield, surpassing an isothermal benchmark by 4.5%. Scaling analysis revealed that the downdraft configuration approached equilibrium hydrogen yields as residence times increased. Staged feeding enhanced performance without increasing the reactor size; an optimized downdraft design achieved a hydrogen yield (56.78 g H 2 /kg biomass) 12.6% higher than an isothermal gasifier, effectively halving the reactor size required. Thus, moving beds offer a promising alternative to isothermal fluidized beds for efficient biomass‐to‐hydrogen conversion.