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Show Met-1 1 Analysis of Combustion System Using High Temperature C O and N2 Mixed Gas Junichi Nakagawa Technical Development Bureau, Nippon Steel Corporation Sintomi 20-1, Futtsu City, Chiba, 293, Japan Abstract The experimental analysis and the numerical simulations for the combustion system using high temperature C O and N2 mixed gas are described. The purpose of this research is to understand the mechanism of combustion using high temperature C O and N2 mixed gas and to investigate the heat distribution by the combustion. The experiments using 600°C fuel gas mixed C O and N2 , have been carried out, and the C O concentration profiles in the pipe were measured. These experiments were conducted in several C O concentrations in fuel gas, several oxygen concentrations in air and several diameters of nozzle. The results indicate that C O concentration profiles are mainly determined by the velocity of air jet from nozzle exit. Also numerical simulations incorporating an eddy-dissipation combustion model have a good agreement with experimental data It seems to be reasonable to conclude that the mechanism of this combustion is followed by turbulent diffusion. 1 .Introduction The flue gas emitted from a scrap melting furnace or a steel converter has so high level's energy, enriched C O and high temperature from 600°C to 1100°C, that it can be utilized for preheating materials charged into the furnace. On the scrap preheating process using a rotary kiln which has been developing on "Research of Environmentally Friendly Technology for the Utilization of Reusable Metallic Materials" conducted by New Energy and Industrial Technology Development Organization (NEDO) in Japan, scrap materials are heated by the combustion of the flue gas emitted from the scrap melting furnace. Since in a rotary kiln heat transfer from the combustion gas to the scrap materials mostly depends on the radiation, making higher temperature region in the front of the rotary kiln gives higher thermal efficiency than the uniform temperature profile. This can be produced by the short flame combustion. In this case, controlling the heat distribution by combustion is important to get high thermal efficiency on heating materials. On the other hand, the reaction rate of the combustion using high temperature gas is so large, that the flow characteristics is more important than the chemical characteristics to control the heat distribution. Therefore, the flow characteristics is crucial to obtain desired heat distribution in these combustion systems using high temperature fuel gas. |