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Show Cross Jet Mixing of Reburning Gas and Secondary Air in Municipal Waste Incinerators Y. Kori Tokyo Gas Co.. Ltd. Energy & Environmental Technology Laboratory A B S T R U CT The natural gas reburning is an attractive method for N O x reduction in municipal waste incinerators. The reburning de-Nox system utilizes hydrocarbon-radicals' reduction effect of N O by injecting natural gas into the incinerator. The reburning is also expected to reduce C O emission and other hazardous components by promoting the mixing. In this technique, the natural gas is injected into the waste burned gas flows. The mixing degree of the reburning gas jet (the natural gas jet) with the burned gas flow is one of the most important factors to reduce them. Cross jet injection into the combustion chamber plays the key role in this mixing process. W e do not. however, well understand the general relationship between the mixing degree and the jet conditions such as the nozzle diameter, the number of nozzles and the jet velocity. In this study, major design parameters are quantitatively investigated by the flow simulation results for simplified model incinerators. The degree of mixing of the jet with the cross gas stream is evaluated in terms of the standard deviation of the jet fluid concentration distributions normalized by mean concentration. The result of this study will provide useful information for designing the jet conditions issuing from the round nozzles in municipal waste incinerators. 1. INTRODUCTION In order to meet public demand for a clean environment, various regulations and guidelines have been proposed. Municipal solid waste incinerators need to meet strict standards for not only N O x emission but also hazardous components such as Dioxins that are specifically generated by the waste incineration. In these days, the application of natural gas reburning is performed as a new technology to solve this problem. W h e n applying the natural gas reburning, attention needs to be paid to the optimization of the mixing between the combustion product and the reburning gas or secondary air. In othe words, mixing is one of the controlling factors to promote the |
