Simulation of sorption enhanced staged gasification of biomass for hydrogen production in the presence of calcium oxide

A novel two-step sorption enhanced staged gasification of biomass for H-2 production was proposed and studied using Aspen Plus software. An equilibrium model based on Gibbs free energy minimization was developed and validated. The results showed that the two-step process was more advantageous for H-2 production compared with the conventional steam gasification and the one-step process. The independent control of each stage could realize a high temperature steam gasification in the first stage and a subsequent lower temperature steam reforming in the second stage, which thus promoted the gasification of biomass and benefited the water gas shift (WGS) reaction to produce more H-2. Meanwhile, the in situ CO2 absorption of CaO in the second stage could enrich the H-2 concentration in the product gas, and also further shifted the WGS reaction equilibrium to convert more CO to H-2. With further introduction of catalyst for steam methane reforming (SMR), highpurity H-2 with the concentration of 99.7 vol% and yield of 142.8 g/kg daf biomass could be achieved. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.