Enhanced hydrogen production using a tandem biomass pyrolysis and plasma reforming process

Converting biomass into energy and fuels is considered a promising strategy for replacing the exhaustible fossil fuels. In this study, we report on a tandem process that combines cellulose pyrolysis and plasma-assisted reforming for H2 production. The hybrid pyrolysis/plasma reforming process was carried out in a two-stage reaction system incorporating a coaxial dielectric barrier discharge (DBD) plasma reactor. The effects of discharge power, steam, reforming temperature, and catalyst on the reaction performance were investigated. The results show that low temperatures are preferred in the non-catalytic plasma reforming process, whereas high temperatures are desired to achieve a high H2 yield and a high H2 selectivity in the plasma-catalytic reforming system. The synergistic effect of plasma catalysis was dominant in the plasma-catalytic reforming process at 250 °C. In contrast, the catalyst, rather than the plasma, played a dominant role in the plasma-catalytic reforming at higher temperatures (550 °C). Using Ni-Co/Al2O3 at a reforming temperature of 550 °C, a high H2 yield of 26.6 mmol/g was attainted, which was more than 8 times and about 100% greater than that obtained using plasma alone and catalyst alone, respectively. This work highlights the potential of non-thermal plasmas in low-temperature biomass conversion.