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

In this study, the enhanced rich H-2 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 H-2 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 H-2. Thus, dry torrefaction was more beneficial for improving H-2 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.

Automated summary

This study enhanced the H2 gas production by co-gasifying torrefied biomass and low-rank coal in a fixed bed reactor. The change in fundamental compositions in biomass after torrefaction played an important role in improving H2 yield, with dry torrefaction being more beneficial. The synergetic effect observed between dry torrefied biomass and coal in certain ratios was mainly due to catalytic species and the transfer of active radicals.