Microwave pretreatment on microalgae: Effect on thermo-gravimetric analysis and kinetic characteristics in chemical looping gasification

A new improvement of chemical looping gasification (CLG) process is based on microwave pretreatment, which is expected to obtain the kinetics analysis of CLG process for the utilization of microalgae. Thermo-gravimetric characteristics of CLG on Chlorella vulgaris are studied in a thermo-gravimetric analyzer under different heating rates and pretreatment conditions. TG characteristics, weight loss rate, reactivity rate, Homogeneous Model (HM) and Shrinking Core Model (SCM) were investigated in order to study the influence of microwave pretreatment on the CLG kinetics for the utilization of microalgae. The results indicated that microwave pretreatment would improve the TG characteristics and reactivity of microalgae. Moreover, the reactivity rate of CLG increased by 5.77% compared with SiO2: Chlorella and it would increase by 6.79% after microwave pretreatment. Furthermore, the higher the heating rate was, the greater the reactivity and weight loss rate of microalgae were. Further, HM could simulate CLG better than SCM. Microwave pretreatment could reduce the activation energy of Chlorella vulgaris and promote CLG. As a result, microwave pretreatment was beneficial to CLG reaction.