An insight into the effects of combined pretreatments of torrefied liquid products washing and torrefaction on chemical looping gasification process of Platanus Orientalis L. leaves

A novel combined process of biomass torrefied liquids washing, torrefaction, and chemical looping gasification (BW/T-CLG) was proposed to realize high efficient utilization of Platanus Orientalis L. leaves (PL). The results of combined pretreated experiments indicated that the torrefied liquids washing decreased the contents of ash and sulfur, and the higher torrefaction temperature decreased the atom ratios of H/C and O/C, while increasing its higher heating value (HHV) and energy density. For the CLG of pretreated samples, the NiO modified iron ore was used as oxygen carrier, and the results showed that the removal of alkali and alkaline earth metals would decrease the BCLG performances. With the reaction temperature increasing from 600 to 800 °C, the lower heating value of syngas increased from 11.28 to 13.80MJ/Nm3, and the indices of gasification efficiency (GE), carbon conversion efficiency (CC), and syngas content (SC) also increased, but the CO selection (SelCO) decreased first and then increased. With the NiO content increasing, the GE and SelCO decreased, but the CC increased. As the OCs-to-biomass ratio grew, the SC and SelCO reduced, but the GE and CC increased first and then decreased, and the best ratio of OCs-to-biomass for the oxygen carrier of 30NiO-IO was 6:4.