Technologies for Controlling Dioxin Emissions in the Process of Municipal Solid Waste Incinerations

摘要

Municipal solid waste (MSW) incinerations are one of the large emission sources of dioxins in Japan. Efforts of their reduction have been succeeded in the inventory of 71g-TEQ/year(2003) compared with 5000g-TEQ/year(1997). There are mainly two measures to control dioxin emissions in MSW incinerations, such as primary measure for combustion and secondary measure after combustion. It is important for controlling dioxin emissions to satisfy 3T(Temperature, Time and Turbulance) in combustion as primary measure, which is performed by the design of furnace and combustion controlling technologies of sensing and predicting. There are two steps in secondary measure, such as to control the dioxin formation in flue gas line after furnace and to remove and decompose dioxins by filtration and catalytic reduction. Both measures can be reached the emissions of dioxins below 0.1ng-TEQ/m~3_N for new incineration plants under continuous operation. Additional measure is needed to reach total amount of dioxins below 5 μg-TEQ/t-waste, which is the target of total emissions in the guideline of waste management for dioxins in Japan. Melting and dechlorination technologies of fly ash have been developed to achieve the target.