Gasification and smelting system using oxygen blowing for municipal waste

Abstract

A new type of waste gasification and smelting system, which uses iron-making and steel-making technologies, has been developed. It is a coke-free process and can produce dioxin-free and high-calorie purified gas and high-quality slag. This report describes the results of a basic concept function test by a bench furnace with the capacity of 2 tons/day based on municipal waste, as well as the operation results of a 20 ton/day demonstration plant. As a result of maintaining the furnace gas at 1 343 K and cooling the gas rapidly, the concentration of dioxins at the exit of chimney was less than 0.01 ng-TEQ/Nm3. The molten slag continuously produced by this system contained very little iron oxides, because iron was removed in advance and the lower part of the furnace was maintained in high-temperature reduction atmosphere. The ratio of heavy metals moving into slag is very small because the temperature is high and heavy metals such as Hg, As, Pb, Cd, Zn and so on are volatile in the furnace. As the absolute quantity of heavy metals contained in the slag is little, the results of the heavy metal leaching test of the slag satisfies the standard value of the test.