Zhuang Sun, Po-Chih Kuo, Xiangxiang Chen, Muhammad Aziz
CO2-assisted biomass direct chemical looping (CO2-BDCL) reduces carbon emissions and facilitates highly efficient biomass conversion. The thermogravimetric (TG) behavior and kinetic studies are crucial for understanding the thermally induced biomass decomposition behaviors and designing reactors in CO2-BDCL. This study investigated the TG behaviors, kinetics, and product distribution of CO2-BDCL. Stepwise experiments were conducted to clarify the interactions among different biomass components and reactions. The results showed that small interactions existed in cellulose and lignin, which slightly lowered the activation energy of the lignin-cellulose mixture compared to individual components. Due to the different reaction temperatures, there was no apparent interaction between pyrolysis and gasification for lignin. The activation energy at the high-temperature zone was generally reduced from 322.09 kJ/mol (N2 atmosphere) to an average of 294.51 kJ/mol (CO2-contained atmosphere). Pyrolysis and reduction co-occurred at high temperatures (>950 K) in BDCL, and the activation energy of lignin-Fe2O3 mixtures (a mean value of 207.8 kJ/mol) was lower than the activation energy of pure lignin. Oxygen carrier reoxidation was observed in CO2-BDCL after 1120 K, causing increased activation energy and dropped conversion. CO2-BDCL promoted both lignin conversion and gaseous yield and reduced tar formation compared to pyrolysis and BDCL. © 2023 American Chemical Society
Department of Mechanical Engineering, The University of Tokyo, Tokyo, 113-8656, Japan; Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan; Faculty of Mathematics and Science, Universitas Negeri Malang, Malang, 65145, Indonesia; Center for Sustainable Resource Science, RIKEN, Yokohama, 230-0045, Japan