Combustion Kinetics of Pellets Made by Sewage Sludge, Pulverized Fuel Ash and River Sludge

Abstract

By using sewage sludge together with river sludge and pulverized fuel ash to produce lightweight aggregates are useful techniques to reuse the sludge. The raw materials was pretreated and manufactured into pellets with diameter range 5mm-8mm and mixture ratio (dry basis) sewage sludge 30wt%, pulverized fuel ash 15wt% and river sludge 55wt%. In order to be more certain about the characters during the combustion process of the pellets at different heating rates, thermogravimetric analysis was employed to study the thermal dynamics. The differential thermogravimetry profiles showed that the combustion process of pellets include five phases and temperature up to the maximal weightlessness speed peak increase with increasing of heating rates. The comprehensive combustibility of pellet decreased with increasing of heating rates. By using improved Coasts-Redfern integration method to calculate the parameters of pellets combustion characteristics, establish the non-isothermal kinetics models and numerically simulate the procedure of sintered LWA. The research results can give service to the simulation of combustion dynamics of taking sewage sludge and other combustible solid-liquid waste materials as raw materials to produce lightweight aggregates by an innovative designed Arc Blade rotary kiln in Chongqing, China.