Makoto Shimizu*, Yoshio Takeuchi*, Minoru Asai*, Takeichi Kondo*, Masanobu Naito* and Hiroshi Aramaki*

* Ishikawajima-Harima Heavy Industries Co., Ltd.

+ Correspondence should be addressed to Minoru Asai:
(3-1-15 Toyotsu, Koto-ku, Tokyo, 135 Japan)

Abstract

Dioxins generated during the incineration of municipal solid waste are synthesized from organic compounds remaining in the combustion process, chlorine and oxygen. Complete combustion of the waste in the incinerator is therefore the primary requisite for preventing dioxin emission. To this end, it is essential to optimize the furnace design and a combustion method which will allow promotion of combustion, particularly for difficult-to-burn solid organic matter (such as char). In order to control the generation of dioxins in municipal solid waste incinerators we conducted basic combustion experiments using small incinerator models of various designs, and selected the swirl-type chamber appropriate for complete combustion. Furthermore, we set up a 20T/D swirl combustion-type fluidized bed incinerator to carry out the demonstration experiment. This revealed that complete combustion could be done as expected and dioxins were also reduced to 0.1ng/Nm3. For increasing nitrogen oxides (NOx) with complete combustion, we tried a noncatalytic denitrification test using urea solution to find that a remarkable reduction of NOx as well as dioxins could be realized.

Key words: swirl combustion, complete combustion, dioxin control, NOx reduction, M.S.W.