Experimental Research on Direct Gasification and Melting Incineration of Municipal Solid Waste

Direct Gasification & Melting technology is tacking with the development of environment-friendly technology and products harmonized with giving impact on the external environment. The technological process can be described as: Waste is fed from one side of the melting furnace. The auxiliary fuels maybe various fuels, such as coal, oil and combustible gas et al. The auxiliary fuel is for melting the waste. The limestone is the basically controller of slag. Air is sent through the third tuyers into the secondary combustion zone, through the second tuyers into the pryolysis and gasifying zone, through the main tuyers into the high temperature combustion and melting zone at the lower portion. In the secondary combustion zone, a high temperature reducing atmosphere is established which suppress the generation of dioxins and pyrolyzed tar. In the pryolysis and gasifying zone, the waste is brought in mild fluidizing state and gasified by the injected high-speed air through the secondary tuyers. Through the zone, the non-combustible components fall into the high temperature combustion and melting zone the bottom of the furnace. The fluidization prevents bridging or hanging obstruction due to mutual melting of plastics and other materials. In the high temperature combustion and melting zone, the combustion of auxiliary fuels and fixed carbon melt the ash. During the flow-down period, the melted ash becomes homogeneous slag. Also in this process, lead and zinc are vaporized and removed from the slag. Then, the slag is continuously extracted through the extracting equipment along with metals. The slag that is recovered from the water bath is treated by magnetic separation to remove metals, and becomes a resource material. The combustion and melting is controlled at temperatures of 1400°C or higher. The concentrations of dioxins were less than 0.1 ng-TEQ/Nm3 at the smokestack outlet and 0.0012ng-TEQ/g at the slag.