CO-COMBUSTION OF RICE HUSK AND SINAI COAL IN CIRCULATING FLUIDIZED BED

Abstract

Rice husk is one of the most important agricultural residues in Egypt. The present study introduces an experimental investigat ion on circulating fluidized bed (CFB) combustion of rice husk and co- combustion of rice husk and Egyptian (Sinai) coal. The test rig is a pilot scale CFB combustor of 145 mm inner diameter, 2 m tall and 10 0 kW thermal capacity. The influences of excess air, and coal s hare were studied. Temperature and heat flux along the reactor height, in addition to the concentrations of CO, NOx and SO2 in the flue gas o ut from cyclone were measured. The combustion efficiency was estimated based on CO and unburned char in flue gas. The highest efficiency recorded for rice husk combustion was 98% at excess air ratio (EA) = 1.1 a nd secondary air ratio (SAR) = 50%. Co-combustion of Sinai coal and rice husk reduced C O but increased SO2 and NOx emissions. The results suggest that rice husk is potential fuel that can be utilized for efficient and renewable energy production by using CFB combustion system especiall y at co-combustion with coal.