Liquid chemical looping gasification of biomass: Thermodynamic analysis on cellulose

Liquid chemical looping technology is an innovation of chemical looping conversion technology. Using liquid metal oxide as the oxygen carrier during gasification process could prolong the service life of oxygen carrier and improve the process efficiency. In this paper, based on Gibbs minimum free energy method, the thermodynamic characteristics of biomass liquid chemical looping gasification were studied. Cellulose and lignin, the main components of biomass, were taken as the research objects. Bismuth oxide and antimony oxide were selected as liquid oxygen carriers. The results showed that when the temperature increased from 600 °C to 900 °C, the output of H₂ and CO in the products of cellulose gasification increased from 0.5 and 0.3 kmol to 1.3 and 2.6 kmol respectively. Different ratios of oxygen carriers to gasification raw materials had the best molar ratio. The addition of steam in the system was beneficial to the increase of H₂ content and the increase of H₂/CO molar ratio. Bi₂O₃ and Sb₂O₃ with different mass ratios were used as mixed oxygen carriers. The simulation results showed that the gasification temperature of biomass with different mixed oxygen carriers had the same equilibrium trend products. It could be seen from the results of product distribution that the influence of the mixing ratio of Bi₂O₃ and Sb₂O₃ on gas product distribution could be neglected. These results could provide simulation reference and data basis for subsequent research on liquid chemical looping gasification.