Effects of oxidative torrefaction conditions on the biomass liquid chemical looping reaction from the perspective of thermal behavior and kinetic analysis

Biomass liquid chemical looping conversion process (BLCLP) can produce a high-temperature oxygen-depleted stream. Utilizing the oxygen-depleted air as a torrefaction medium can enhance biomass reactivity and achieve higher energy efficiency. This study aimed to investigate the effect of torrefaction conditions on biomass reactivity in the BLCLP. The torrefaction under proper working conditions effectively enhanced the release of biomass volatiles. The increase in the activation energy of biomass pyrolysis after oxidative torrefaction indicated the need for proper control of the torrefaction condition. More importantly, oxidative torrefaction promoted the reactivity between biochar and liquid oxygen carrier, which was crucial for the BLCLP. The activation energy of the reaction between biochar and Sb₂O₃ liquid oxygen carrier calculated by the DAEM method was 289.75–296.79 kJ·mol⁻¹, guiding the subsequent reactor design. Ultimately, the optimal torrefaction conditions for the BLCLP were determined as 270 °C and 3 vol% oxygen content.