High purity hydrogen production via coupling CO2 reforming of biomass-derived gas and chemical looping water splitting

Abstract

Hydrogen is playing an increasingly larger role in carbon neutrality. However, efficient and sustainable hydrogen production from renewable resources suffers from unwanted side reactions and kinetic inefficiencies. Here, we study a low carbon and renewable H2 production route that integrated biomass-derived gas dry reforming couples chemical looping water splitting process (DR-CLWS). This process requires neither removal of CO2 from upstream biomass-derived gas, nor downstream H2 purification and CO2 separation, hence achieving a great level of process intensification. The reforming temperature, CH4/CO2 ratio, oxygen carrier reduction temperature, reduction behavior, types of fuel gas and oxygen carriers, H2 production, oxygen carrier regeneration and process cyclability were investigated, respectively. The coupling process resulted in higher CH4 conversion (near 100%) and inherently CO2 separation. CO-free H2 was produced due to no carbon being carried over from the reduction cycle to the H2 production cycle. Meanwhile, H2 yields up to 2.93 mmole per mmole CH4. Mass balance analysis reveals that the process can be operated auto-thermal without costly oxygen production or without mixing air with carbon-containing fuel gases. Moreover, the cyclability results showed that the oxygen carrier remained its activity over 265 redox cycles.