CO2 sorption and sorbent depressurized regeneration in circulating-turbulent fluidized bed regime

Abstract

The circulating fluidized bed reactor can be used to capture CO2 continuously by performing three different processes: CO2 sorption in riser, gas-solid separation in cyclone, and sorbent regeneration in downer. The semi-continuous mode of the reactor is employed to screen out the effect of operating parameters by ANOVA analysis. Superficial gas velocity is the crucial operating parameter, which provides a significant positive trend on CO2 sorption capacity. Due to the interaction between operating parameters, the solid recirculating rate must be optimized to achieve high sorption capacity. The inclination of downer bottom should be greater than the angle of repose of the sorbent particle. Depressurized regenerator downer is the most important part to complete circulating sorption and regeneration as a continuous mode. One of the poor operations at 47.21 mg-CO2/g-sorbent (Ug of 1.0 m/s and Gs of 100 kg/m2.s) is selected as a task for performing continuous mode. The result shows that CO2 capture capacity improves by three times. The concentration profile of the treated gas is constant about a half of the breakthrough concentration and no trend reaching the breakthrough point.