OCR Text |
Show 5. Conclusion Three type of regenerative combustion system was developed and installed to steel making process. And the results of developments and installations were summarized as below. Development of regenerative R/T burner (1 )The developed burner has high heat efficiency of 8 0 % or more and the low N O x performances of 120ppm or less in 960°C in furnace temperature and amount H O W of combustion. (2)The system which was developed achieved the longevity of the burner, regenerator, and the switch valve and was verified high reliability as the entire system. (3)Regenerative burner system have been operating smoothly without the damage of regenerator and leak of the switch valve. Development of regenerative direct firing burner (4)The regenerative burner of 5,800kW which was the world-biggest class was developed and installed to wide flange beam mill furnace, Kawasaki Steel's Mizushima Works, and operating smoothly. (5)Developed burner system has high heat recovery rate over 8 0 % and the low N O x emission of 130ppm or less at 1300°C. (6)High high efficiency control system and high turn down combustion system were established at the furnace. Development of N2 jet heater (7) A n N2 jet heater was developed for non-oxidizing heating of the steel making tundish. With this device, a storage type heat exchanger is used to heat to high temperature N 2 gas. (8) Use of the N2 jet heater makes it possible to reduce the oxygen concentration in a tundish, to an average of under 300ppm, enabling heating under substantially a non-oxidizing condition. (9) A s a result of the above (8), the rate of occurrence of inclusion-related defects in steel materials has been reduced to 1/5 to 1/3 the past level. (10) It is considered possible to apply this device in other fields where non-oxidizing heating is required. References l)Gettings M.:Gas warme International,35,5 (1986)292 2)S.Relph:Steel Times, 216, 3(1988)150 3)J.D.Bowers:Adv Mater Processes, 137,3 (1990)63 4)T.Nakagawa,et al.:TETSU-TO-HAGANE (Japan), 78(1992)T149 5)K.Nakanishi,et al.:CAMP(Japan),5(1992) 1547 6)S.Yuhara,et al.:CAMP(Japan).9( 1996)770 7)K.Hara, et al.:CAMP(Japan).9( 1996)231 |