Currently

safe and efficient treatment/disposal of residual sludge is a thorny problem in China. Drying and incineration can realize innocuity and reduction of sludge. This study establishes a calculation model for typical sewage sludge independent drying-incineration and discusses the influences of low heating value(LHV) and primary air temperature on sludge combustion temperature and auxiliary fuel requirement. The results show that

the combustion temperature and critical moisture content of the sludge increases with the sludge heat value

the critical moisture content is about 45%

51% and 54% respectively for incineration of sludges with 10

12 and 14MJ/kg LHV. Increasing primary air temperature can significantly increase the combustion temperature of sewage sludge. However

when the sewage sludge is with LHV of 12～14 MJ/kg and the primary air temperature is above 200 ℃

the combustion temperature will be above 950 ℃

so cooling measures should be taken. The auxiliary fuel requirement of the dry-incineration system is higher than that without drying system because the heat provided by the sludge itself cannot meet the total energy consumption of the sludge dry-incineration system. The auxiliary fuel requirement of the dry-incineration system increases with the decrease of the moisture content.