The enhanced rich H2 from co-gasification of torrefied biomass and low rank coal: The comparison of dry/wet torrefaction, synergetic effect and prediction

Abstract In this study, the enhanced rich H2 gas was produced via the co-gasification of torrefied biomass and low-rank coal in the fixed bed reactor. The properties of wet/dry torrefied char was compared, and then the synergetic effect between dry/wet torrefied char and the low rank coal during the gasification were analyzed to study the enhancing effect of torrefaction on the H2 yield. Moreover, the co-pyrolysis reactivity and kinetic analysis were investigated to further determine the synergetic mechanism. The results showed that the change of fundamental compositions in biomass after torrefaction, especially, the removal of cellulose played an important role in the enhancement of H2. Thus, dry torrefaction was more beneficial for improving H2 yield than the wet one. Besides, an obviously synergetic effect was observed from coal and dry torrefied biomass in their ratio 1:1 and 3:1, which was mainly due to the catalytic role of alkali and alkaline earth metallic species, and the transfer of active OH and H radicals from the torrefied biomass to the coal. The co-pyrolysis reactivity and kinetic analysis further proved the synergetic effect on reducing activation energy.