Biomass chemical looping: Advancements and strategies with the moving bed reactor for gasification and hydrogen generation

Abstract

This work presents advances in OSU's BTS technology, targeted explicitly toward hydrogen production from experimental and process simulation results. Two experimental parameters: residence time and enhancer steam flowrate, are explored. A volume reduction of ∼67 % can be achieved in Reducer while ensuring high char conversion. The steam injection enhances char gasification and H2 content; however, it may lead to increased tar content due to decreased gas residence time. The steam injection of ∼5 % of the inlet carbon flow rate can be adequate for efficient biomass gasification and injecting additional steam downstream into the WGS unit is optimal for H2 generation. Two cases that implement modularization for tighter process integration are compared with the conventional BTS and BDCL processes for H2 generation. The application of modularization eliminates the energy-intensive AGR unit and increases ETE by ∼17 % over the BTS process. Modularization offers product flexibility and increased control with lower operational risks over the BDCL process but at 7 % lower ETE, which can be attributed to the high amounts of oxygen present in the biomass, leading to decreased syngas purity. H2 yield can be further increased by co-injection of low oxygen feedstocks such as plastics, which can increase H2 yield by ∼12 %.