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Show 10 5. CONCLUSION (1) An improved heating method combining high temperature excess-enthalpy combustion with gas recirculation were proposed making it possible to have a uniform temperature profile in furnaces and to increase the average temperature. (2) A one dimensional plug flow type of furnace model was studied and the level of the heat loss from recirculating gas was proved to strongly affect the gas temperature in the fu rnace. (3) The operation increasing both gas recirculation ratio and heat recirculation can result in the reduction of both the maximum temperature and temperature gradients in the furnace. It can be expected this could, in principle, also obviously bring about NOx reduction. (4) Thermal efficiency was improved by the operation of increasing gas recirculation and heat recirculation while maintaining a constant maximum flame temperature. It was found an optimum point exists in terms of satisfying thermal efficiency improvement and NOx abatement. ACKNOWLEDGMENT This work was supported by New Energy Development Organization under the contract project of New Industrial Furnaces of Higher Thermal Efficiency. REFERENCE (1) Mochida, S., Hasgawa, T. and Tanaka, R., "Advanced Application of Excess Enthalpy Combustion Technology to Boiler Systems", Presented in 1993 AFRC International Symposium, Tulsa, Oklahoma. \ |
