Analysis and Optimization of Autothermal Operation Parameters for Semi-Coke Chemical Looping Gasification System

To achieve efficient and clean utilization of semi-coke, an autothermal chemical looping gasification system for syngas production from semi-coke is proposed. Based on the principle of Gibbs free energy minimization and the laws of energy and mass conservation, a chemical looping gasification model with a processing capacity of 2000 t d^-1is established and validated with experimental data. The effects of key parameters, including gasifier temperature, air reactor temperature, and steam-to-carbon molar ratio, on system performance are investigated. The optimal autothermal operating conditions for the semi-coke chemical looping gasification system are determined and compared with conventional semi-coke gasification in terms of thermal efficiency. The results demonstrate that under a semi-coke feeding rate of 83. 33t h^-1the optimal autothermal operating conditions are: steam flow rate of 108. 99t h^-1gasifier temperature of 900 °C. air reactor temperature of 1000 °C, air flow rate of 247.25t h^-1mass ratio of oxygen carrier (CaSO₄/Fe₂O₃) to semi-coke feed of 1.92, and mass ratio of heat carrier (Al2O3) to oxygen carrier of 16.29. Under these conditions, the system achieves a syngas mass flow rate of 80. 13t h^-1with a production yield of 1 700 cm³kg^-1The overall thermal efficiency of the chemical looping gasification system reaches 83.81%, significantly higher than the 80. 51% efficiency of conventional semi-coke gasification, primarily due to the elimination of the air separation unit for oxygen production. This demonstrates notable performance advantages and development potential. The findings provide important references for industrial applications of semi-coke chemical looping gasification.