Study and Application of the Pyrolysis-Combustion Process for the Sewage Sludge

Abstract

This paper designed and investigated the pyrolysis combustion process of the sewage sludge, based on the combustion properties and self-sustained combustion conditions of the sewage sludge. The water content of the sludge was first reduced to less than 55% through the mechanically dewater. Then, the sludge was combusted in the pyrolysis-combustion chain grate stoker. A sewage sludge pyrolysis-combustion system was designed, with the processing capacity of 15 tons of sawage sludge per day. The results of the pilot test show that a dynamic equilibrium was reached among the drying, pyrolysis, gasification and combustion process. In addition, the emission of the pollutant reached the national standard of the pollutant discharging criteria. The system owns the advantages of less investment, low operation cost and environmental friendliness. Furthermore, the system may solve the problem of the excess sludge accumulation of the wastewater treatment plant. The waste heat can be recycled, and the burning ash can be used as construction materials.