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Show 1 Development of Efficient Combustion Technology Applying High Cycle Regenerative Heat Exchange System T. NAKAGAWA, K.KARUBE. K. HARA, J. OZAKI Mizushima Works, Kawasaki Steel Corp. Kawasakidori l-chome, Mizushima, Kurashiki. Okayama 712, Japan Abstract We have developed a cost effective and environmentally safe high cycle regenerative heat exchange system. This system is equivalent to a regenerative burner when the combustion air is used for the preheated gas. W e have implemented biggest regenerative burners in both radiant tube (R/T) type and direct firing type by developing the following technologies: (1) a low N O x emission combustion technology at high preheat temperature, (2) an optimal control technology on the gas flow rate through the regenerator. The R/T burner is n ow used in No.2 Continuous Annealing Line and the direct firing burner is used in the reheating furnace of the wide flange beam mill at Mizushima Works. Using these burners, the fuel of 1 5 % or more has been saved. W e have also implemented a non-oxidizing heating system (N2 jet heater) using high-temperature inert gas injection by developing the following technologies: (1) a regenerative heat exchange system with an internal combustion chamber, (2) a valveless high temperature gas injection system, (3) an atmosphere control technology in a furnace in order to accomplish the non-oxidizing heating over 1,773K, which was considered very difficult with the existing technologies. The system was introduced in the No.4 Slab Caster first time in the world and improved the quality of cast slabs. 1. Introduction In recent years anathermal of the earth and acid rain by CO2 came into question,and public opinion is strongly in favor of the preservation of the environment. Furthermore "FramewConvention on Climate Change" has been ratified in 164 nations since 1996. W e , Kawasaki Steel Corp., have focused a cost effective and environmentally safe high cycle regenerative heat exchange system. Regenerative burner which is one of typical techniques of high cycle regenerative heat exchange systems is proposed in 1980's in Britain, and using this burner, the fuel of 2 5 % or more can be saved compared with the burner where waste heat was recovered with conventional recuperator. O n that account a lot of burners were put to practical use in Europe and America1 ~3). But installation in Japan was late because of its high N O x emission by very high preheat temperature, and low reliability. We set about the development on low NOx regenerative burner at the same time when "Framework Convention on Climate Change" was carried in 1992. A nd when this convention was came into effect in 1994 , we succeeded to put low N O x regenerative R/T burner to practical use in No.2 C A L . And reduction of N O x emission, high efficiency control system were |