Design of Co-Combustion & Drying Integrative Process of Paper Sludge and Experimental Study

Co-combustion of sludge with coal could be an interesting option to dispose this solid waste in China. TG (thermogravimetric) experiments indicated that the co-combustion of paper sludge and coal showed the integrative profiles of each individuals, and the blends with sludge content less than 20%wt behaved approaching to coal, although showing some differences. In addition, the early volatiles liberation from the paper sludge could mean an advantage when attempting to initiate the process. A integrative technology was designed to made use of the drying capability of fluidized bed to dry sludge, at the same time use the high moisture of paper sludge to realize flue gas partially desulfurization. The case analysis shows that for a news paper plant with raw materials production about 400,000 tons annual, the heat discharged by flue gas can satisfy the drying requirement sufficiently, even for the initial moisture content of sludge high about 80%. The experimental results in small-scale equipment indicated that the integrative process can achieve excellent drying requirements; however, the desulfurization efficiency is very low, due to the problems of mixture and hydrated degree of desulfurizer. More effort should be devoted to improve this technology further.