Abstract

The aim of this study was to design and operate a cascade cyclone calciner for sorbent regeneration in a pilot-scale calcium looping carbon capture process. The calciner was designed on the basis of mass and energy balance analysis of a 500kW_th system. Effects of flue gas recirculation (FGR), and fuel feeding rate on the sorbent calcination efficiency were investigated. Calculation results determined the capacity of the diesel-fired oxy-combustor applied in the calciner and the geometric dimension of the 500kWth calciner. Experimental results indicated that the flue gas recirculation stabilized the temperature distribution inside calciner. Approximately 200°C temperature gradient through the cascade cyclone calciner was achieved in this study. Both the temperature distribution of flue gas and the migration path of sorbents inside calciner affected the calcination efficiency. The enhancement in flue gas recirculation rate provided more flue gas inventory for sorbent transportation and the increase in fuel feeding rate offered more energy for sorbent calcination. The increases of fuel feeding rate from 46 L/h to 50 L/h and the flue gas recirculation rate from 3380 CMH to 3870 CMH led to almost 4.6 times enhancement in the sorbent calcination efficiency. The calcination efficiency higher than 80% would be realized for experiments using fuel feeding rates higher than 50 L/h.