Effects of Municipal Solid Waste Torrefaction and Classification Pretreatment on Hydrogen Chloride Release

Abstract

The incineration treatment of municipal solid waste is widely used, but gas-phase hydrogen chloride (HCl) generated during the incineration seriously threatens the heating surface of boiler tail, and even causes serious harm to environment. Through incineration experiments, this paper found that many factors (temperature, oxygen concentration, residence time and moisture content) affect the HCl emission characteristics in the process of municipal solid waste incineration treatment. In order to effectively cut back the HCl emission in incineration treatment of municipal solid waste, this paper proposes torrefaction and classification pretreatment of municipal solid waste. Torrefaction pretreatment has a significant inhibitory effect on HCl emission during the incineration of mixed municipal solid waste. At the same time, compared with the incineration treatment of mixed municipal solid waste, sawdust and plastic municipal solid waste of the same quality after classification pretreatment can effectively curb HCl emissions within the entire temperature range. In particular, HCl emissions are reduced by 35% during sawdust incineration treatment at 400°C. Furthermore, by studying the reaction mechanics of HCl generation during combustion at different temperatures, and the reaction rate of HCl generation is: mixed municipal solid waste >plastic >sawdust. Therefore, this paper believes that torrefaction and classification pretreatment of mixed municipal solid waste is beneficial to inhibit the precipitation of chlorine during the incineration process and promotes the resource utilization of municipal solid waste, which is of significant significance for energy conservation and emission reduction.