Experimental Research on Harmless Technology of Municipal Solid Waste Incineration With Direct Gasification and Ash Melting

A novel harmless MSW disposal, incineration technology with direct gasification and ash melting was developed, with experimental investigation. The technological process can be represented as: the pretreated MSW was put into an incinerator and incinerated in a molten bath under reduction atmosphere at a temperature range from 1300°C to 1500°C. In order to maintain the stability of the combustion process, it is needed to blast combustion-supporting coal powder from the bottom of the incinerator. Combustible gases were leaded and burned completely in a secondary swirled combustion chamber, and the heat was recycled and come into utilization. In some cases, molten slag and alloy were discharged from a same slag notch, and then they were quenched and separated each other. In other cases, melted slag and alloy were discharged from two different notches, and quenched in their own quenching pool. In both the former and the later case, the alloy was recycled and the melted slag can be used as construction materials in the same way. Experimental results form an industrial-scale pilot plant show that the investments of capital construction and running cost of this incineration system are only 65–85 percent of those of the similar types incinerator developed by western countries. It is necessary to point that 99.8 percent of dioxins involved in primary MSW were decomposed, and the dioxins content in exhausted gases and melted slag were lower than 0.01ng-TEQ/Nm3 and 0.0012ng-TEQ/g respectively.