Comparative analysis of hydrogen production systems from biomass based on different absorbent regeneration processes

Hydrogen production through single-step process has been proposed for a long time. The process can produce H2 in gasifier, and simultaneously, achieve integration of exothermic and endothermic as well as gas production and separation in one reactor. The process consists of mainly twin fluidized beds—a gasifier and a CO2 absorbent regenerator. In this paper, two modes are suggested for absorbent regeneration. One case named PCC process is partial carbon conversion in the gasifier, and the carbon residue acts as a fuel for the regenerator; the other case named NO process is nickel oxidation in the regenerator to supply heat for absorbent regeneration. The mass and energy balances and cold gas efficiency were analyzed by thermodynamic calculation for the two different processes. When the feedstock is same, PCC process gives a higher cold gas efficiency of 0.74 than NO process of 0.67.