Three-Dimensional Full-Loop Simulation of Gas–Solid Flow Behaviors in a Chemical Looping Gasification System with a Two-Staged Fuel Reactor

Abstract

The structure of the fuel reactor (FR) has a considerable influence on the performance of chemical looping gasification (CLG) of solid fuels. In this work, a three-dimensional multiphase particle-in-cell method was constructed and applied to investigate the gas−solid flow behaviors in a full-loop CLG system with a novel two-staged FR. After model verification against experimental data, the flow characteristics, pressure drop, solid circulation rate, spout incoherence, and particle attrition were systematically explored under different operating conditions. The results show that increasing the FR inlet gas velocity and initial spouted bed height generally increases the pressure drop across the FR. Moreover, different parameter values noticeably influence the solid circulation rates at the FR particle outlet and the rectangular channel connecting the two fluidized beds. The spout incoherence appears in the two-staged FR during continuous operation, and increasing the initial spouted bed height decreases the dominant frequency of particle blockage. Additionally, a larger FR inlet gas velocity and initial spouted bed height or a smaller rectangular channel width intensify the particle attrition in the spouted bed of the FR and lead to a higher peak attrition rate. All of these observations and findings provide valuable guidance for the design and optimization of the two-stage FR and the full-loop CLG process.