Fundamental Study on Post-combustion Technique in Strongly Stirred Iron Bath Reactor

Abstract

Post-combustion technique in converter is regarded as an essential measure for high scrap-ratio operation or scrap melting. It is also one of the key technologies to develop smelting reduction process. Effective technique of post combustion, however, has not been completely developed yet. Some factors in obtaining high heat transfer efficiency with high degree of post combustion was investigated by using 40 kg and 400 kg scale converters. As a result it was found essential to carry out post combustion in slag layer. To achieve an aimed high degree of post combustion, oxygen for post combustion or the resultant oxidized gas should avoid the reaction with reducing agents such as C in metal droplets. That requires a proper design of nozzles for post combustion and minimization of droplet generation. Heat transfer efficiency, η, was expressed as a semi-empirical equation of post-combustion ratio, OD, and parameter, P, representing operational conditions. This equation showed that P value should be increased to improve η at an aimed OD. It was found that parameter P had some relation with the ratio of the characteristic length for heat exchange zone in slag layer to superficial velocity.