Abstract: As an efficient sludge disposal process, municipal sludge drying and incineration has been increasingly used in Chinese large and medium-sized cities in recent years. An energy-balance model for the systems of a typical drying and incineration process of municipal sludge was established, the energy balance of each system was calculated and analyzed. The results showed that the lower calorific value of dry sludge should reach about 14 200~15 500 kJ/kg to meet the self-sustaining energy balance of the system. Supplementary energy supply was needed when the sludge calorific value was insufficient. Steam was more economical than natural gas as a supplementary energy supply. In the site selection planning of sludge drying incineration project, environmental protection industrial park could be considered for steam coordination.Considering the rationality and economy of the process, it was recommended to control the water content of sludge in sludge incinerator at 60%~70%.

Key words: municipal sludge, drying, incineration, energy balance