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Show Main characteristics in high temperature air combustion which has homogeneous furnace temperature, raising the average furnace temperature, increase of convection heat transfer and utmost waste heat recovery generate increase of heat transfer capacity and minimization of heat loss, then these contribute to achieve high performance. Table 5 shows comparison result of high performance furnace and conventional furnace designed under the same condition. Fig.20.1 and Fig.20.2 show the result of practical design images. Consequently the performance and characteristics of high performance reheating furnace are as follows. ©Saving energy It is the main reason for saving energy that we can get easily high temperature air of 1,000-1,200'C and get waste heat recovery efficiency of 80% level. Besides the decrease of cooling loss and radiation heat loss from furnace body by compactness of equipment are added, then we can attain 80% of thermal efficiency and 30% of saving energy. (D Downsizing We recognize about 10% increase of heat flux to the heated material compared with conventional combustion by high temperature air combustion. In addition to increase of heat flux, homogeneous heating effect on the material affects decrease of discharging cross average temperature in slab heating case and we can produce box style in furnace profile by adoption of all side burners, then we have no nose part of furnace in billet heating case. Finally we can realize big reduction of furnace length and furnace height. We get downsizing of about 35% in furnace volume compared with conventional furnaces. (DNOx We can attain very low NOx by high temperature air combustion using high temperature air, above 1,000'C, and as a total of reheating furnace we can clear the environmental regulation value of NOx with no problem. SUMMARY This project involves research and development based on the results of basic research on combustion represented by the clarification of the formation mechanism of NOx during high temperature air combustion and it is necessary to clearly present an "image of hardware of each high performance furnace" as well as to deepen the basic research. For this purpose, it is necessary to accumulate reliable basic data using adequate experiments for building data bases of basic component techniques capable of providing design and operation policies and besides to make full use of high level simulation techniques of compound system of heat transfer, flow and combustion reactions based on physical models. Because the durability and reliability of hardware, stability of the whole system, operation know how,etc., cannot be established in putting high performance industrial furnaces into practical use only from the experiments on high performance industrial furnaces, the authors intend to make furnaces capable of withstanding practical use by thoroughly surveying the actual results of regenerative industrial furnaces that have already been put into practical use and building data bases of the results of use. The authors intend to contribute to the improvement of Japan's and the world's combustion technology in the future. At the same time, they intend to contribute to the realization of measures to curb global warming and to the improvement of the economic efficiency of these measures by making efforts to put the results of development into practical widespread use. ACKNOWLEDGEMENT This paper is part of High Performance Industrial Furnace Development Project with - 8 - |
