Population balance for CFB–FGD systems

Population balance is the basis of stable and effective operation of circulating fluidized bed flue gas desulfurization systems (CFB–FGD systems). The population balance model parameters were calibrated by comparing the calculated results for a CFB–FGD system with experimental data from a bench-scale CFB–FGD system. The relative error was less than 5.1%. The influences of the model parameters, reactor structures, operating conditions, and adhesive carrier particles on the population balance of the CFB–FGD system were then analyzed using the calibrated population balance model. The results indicated that particle segregation and the superficial gas velocity strongly influenced the particle size distribution. The cyclone separation efficiency and the selected particle draining coefficient also impacted the particle size distribution and the bottom ash ratio. The calcium to sulfur ratio and the bed temperature mainly influenced the bottom ash ratio and the desulfurization efficiency of the system. The anti-abrasion characteristics of the rapidly hydrated sorbent influenced the particle size distribution, the bottom ash ratio, and the desulfurization efficiency of the system. The population balance in the CFB–FGD system was more easily achieved when circulating ash from a CFB boiler was used as adhesive carrier particles instead of coal fly ash. This research provides guidance for stable, effective operation of CFB–FGD systems to promote industrial applications of CFB–FGD technology.