Study on influence factors and control optimizations of sewage sludge drying and incineration system for energy conservation

Sewage sludge drying and incineration technology has become more and more popular worldwide recent years, while high energy consumption problem is always accused. Taking a large sludge drying and incineration plant of Shanghai as a research object, the operation data show that external energy consumption is the main part of operation cost due to energy gap of heat balance. Heat balance models are created for both sludge drying and incineration systems and theoretical calculations and analysis are made to study the rules of the influence factors including sludge original moisture content, sludge heat value, dry sludge moisture content and operation load on energy consumption of the systems based on the design parameters. Operation data show that correlation indexes between system total energy consumption and the four influence factors are 0.47, 0.50, 0.27 and 0.03 in sequence, indicating that the first three factors should be the main objects to be controlled and optimized. Former water treatment and sludge dewatering process can be optimized to obtain low water moisture content and high heat value of sludge to realize energy conservation when drying and incineration technology for sludge treatment is adopted.