ESTUDO DO COMPORTAMENTO METALÚRGICO DO REATOR KAMBARA ATRAVÉS DE MODELAGEM FÍSICA

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The quality requirements of many steel grades are becoming increasingly important due to demand of alloys for sophisticated applications. The sulfur and phosphorus contents of steel grades have become stringent. Sulfur is undesirable except for machinability applications. The tolerance limit for sulfur content is around 50 ppm maximum in the case of many applications. To achieve this is important to control sulfur in the hot metal charged to LD vessel. Since the sulfur activity coefficient is 5 times greater in the hot metal than in steel hot metal desulfurization should be favorable. The blast furnace hot metal can be desulfurized either in torpedo car or in the hot metal ladle. Agitation of hot metal by mechanical means should be better due to renewal of surface as in the case of Kambara Reactor(KR) than in the case of agitation inside torpedo car by pneumatic means. The Kambara Reactor is definetely more efficient and has lower production cost. The Kambara Reactor is preferred in Japanese steel plants than elsewhere. In respect to metallurgical performance this process is preferred by companies that are deciding about alternatives available for Hot Metal Desulphurization from the point of view of efficiency and operational costs. The objective of this work is to investigate the Hot Metal Desulphurization in Kambara Reactor (KR), using physical modeling as a tool in order to simulate industrial process. A physical model has been constructed in the laboratory and operated. The impeller design, the rotation speed, the hot metal ladle shape, the fluid characteristics, etc are taken into account in the similarity criteria for design the model. A model, scale 1/7, based on similarity criteria was built at the Department of Metallurgical Enginering of Universidade Federal de Ouro Preto using acrylic material for the ladle vessel, water simulating the hot metal, and kerozene for slag. Mixing and mass transfer studies were carried out to get a deeper understanding of KR metallurgical performance. A comparison between two impeller designs (A and B) as far as mixing and mass transfer are concerned is presented. Macromixing in a KR seems to be faster than the chemical process which is controlled by mass transfer at the several restrictive layers around the particle desulfurizer. Macromixing can be improved but is limited by the available freeboard. Impeller B allows higher freeboards for the same immersion. Dispersion is more effective at shallower depth of immersion and higher impeller speed.

ASSUNTO(S)

metalurgia engenharia de materiais e metalurgica dessulfuração misturas siderurgia

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