Numerical Simulation of Co-Firing of Municipal Solid Waste and Sludge in a Large-Scale Incinerator

Abstract

Incinerator is an important ways of recycling municipal solid waste. The massive construction of waste incineration plants and the increase of municipal sludge provide the possibility for sludge blending with waste. In the current sludge co-firing process, effect factors such as raw material characteristics, primary and secondary air conditions, and combustion parameters will all affect the combustion processing. This study intends to predict the effect of blending combustion by means of computational fluid dynamics, and analyze the effects of sludge blending ratio, moisture content of sludge, the ratio of primary air and secondary air, total air volume, and fuel feed rate. The influence of solid-phase combustion and gas-phase combustion in the furnace. Under the condition of sludge and municipal solid waste mixed, sludge will reduce the furnace temperature and flame height; the best combustion condition with the ratio of primary and secondary air is 0.72:0.28; A low total air volume cause a poor combustion. Completely, a high total air volume leads to a low furnace temperature; the fuel feed rate in the range of 500-550 t/d has a good combustion condition; the sludge moisture content in the range of 45%-55% has a better economy.

Keywords: Municipal solid waste incinerator, Sludge mixed, numerical simulation, co-combustion, Moisture content