Toshihiko Kukutsu*, Osamu Kawaguchi** and Eiichi Shibuya***

* Graduate School, Keio University (Current Affiliation: Kawasaki Steel, Co.)
** Faculty of Science and Technology, Keio University
*** NKK Corporation

+ Correspondence should be addressed to Kawaguchi Osamu:
(3-14-1 Hiyoshi, Kohoku, Yokohama 223 Japan)

Abstract

A new type of municipal waste incinerator was examined through a series of experimental works using hot and cold model furnaces and numerical analyses on the gas flow. The 2-way flow incinerator reduces pollutant gas emissions, such as dioxins, by dividing the combustion gas in the primary stage into CO-rich gas and O2-rich gas and then impinging each other in the secondary combustion region to promote mixing and complete chemical reactions. To examine combustion process in the secondary region of the incinerator, combustion gas in the combustion region of the hot model furnace was analyzed, mainly taking notice of carbon monoxide which is connected to dioxins. By using cold models of similar sizes together with the hot model, the mixing processes after impingement of the two jets were also examined, and the relationship between a practical furnace and a hot model furnace was verified. The experimental and numerical analyses reveal the relationship between the mixing process in the furnace and CO oxidizing, as well as the NOx production reaction processes which are affected by the distribution ratio, reference velocity, furnace temperature and so on.

Key words: 2way-flow incinerator, combustion process, mixing process, CO emission, dioxins