Process simulation and reaction performance evaluation of CO2 chemical looping conversion based on modified bauxite residue oxygen carriers

Abstract

A large number of greenhouse gas emissions have brought a series of environmental problems, so it is urgent to realize efficient conversion of CO2. The multistage regeneration process of CO2 chemical looping conversion was established and the process simulation analysis carried out with Aspen Plus. The system’s feasibility was verified by simulation and the process needed to provide additional energy input, and the sensitivity analysis of different operating conditions was carried out to provide guidance for subsequent experimental design. Oxygen carrier bauxite residue was modified by acid washing and CeO2 impregnation, and the reaction characteristics were evaluated via a fixed-bed reactor and on-line mass spectrometry, and the kinetic parameters of the reaction were solved by gas-solid reaction kinetics. The results showed that 12 wt% CeO2 loading oxygen carrier had the highest yield and average formation rate of CO, which were 6.22 mmol·g−1 and 388.71 μmol·g−1·min−1, respectively. The oxygen carrier conversion (oxygen vacancy utilization) was close to 100% after modification, while that of single bauxite residue oxygen carrier was only 60%. The reaction system conformed to the first-order reaction model, and the activation energy was 33.90 kJ·mol−1. This study provided new insight into chemical looping conversion of CO2.