SULFUR OXIDE EMISSION AND LIMESTONE UTILIZATION IN 2-STAGE SWIRL-FLOWFLUIDIZED-BED COMBUSTION OF SEWAGE-SLUDGE

Sewage sludge combustion experiments are carried out to investigate th e effect of operating parameters on SO2 capture and limestone utilizat ion in a two-stage swirl-flow fluidized-bed combustor. Operating param eters investigated in the study are the Ca/S molar ratio, superficial gas velocity, bed temperature, air-fuel ratio, and particle size of li mestone. The experimental results show that the increase of the Ca/S m olar ratio results in the increase of SO2 capture, whereas it causes t he decrease of the limestone utilization. The SO2 capture tends to inc rease with the superficial gas velocity and total air-fuel ratio, but has a maximum value at a temperature of about 800-degrees-C. It is als o noted that a smaller limestone size significantly enhances the SO2 c apture and the limestone utilization.