Abstract:As the main technology of sludge harmless treatment, sludge drying and incineration in urban sewage treatment plants are more and more used in engineering. In the theoretical process calculation of sludge incineration, many key technical parameters such as sludge combustion calorific value, flue gas composition and flue gas enthalpy can be obtained. In this paper, the thermal calculation method of coal-fired boiler was used to analyze the influence of different moisture content on the temperature of sludge incineration flue gas through theoretical calculation, and the moisture content of sludge self-sustaining combustion was calculated by interpolation method. At the same time, the amount of auxiliary fuel ( general industrial solid waste ) needed to be added when the temperature of sludge incineration flue gas with different moisture content reaches 850 °C required by the standard was calculated theoretically. The research shows that the higher the moisture content of sludge, the lower the temperature of sludge incineration flue gas, and the more auxiliary fuels need to be supplemented; generally, industrial solid waste has a high calorific value and can be used as an auxiliary fuel for sludge, which can be used in conjunction with sludge incineration.