Efeito da configuração do bico da lança na interação jato-banho metálico em convertedor LD

Exportado OPUSMade available in DSpace on 2019-08-14T10:26:16Z (GMT). No. of bitstreams: 1 breno_totti_maia.pdf: 5840625 bytes, checksum: 358107a592e91f70088469fc3293ca6f (MD5) Previous issue date: 28Com a crescente demanda de produção de aço, os convertedores LD vêm sendo acrescidos de novos equipamentos e técnicas que continuamente aprimoram os padrões operacionais. A aciaria da Gerdau Barão de Cocais, operando inicialmente com um convertedor de 18 toneladas por corrida, também evoluiu em seus métodos e agregou tecnologia aos seus processos, permitindo alcançar a capacidade de 30 toneladas de aço vazado por corrida, com o mesmo lay-out desde sua inauguração em 1979. O processo de produção de aço é dividido em etapas, sendo a principal o sopro de oxigênio no banho metálico. A redução do tempo de sopro significa o aumento direto da capacidade de produção, uma vez que as demais etapas do processo já se encontram otimizadas. O estudo do sopro de oxigênio é complexo, pode ser dividido em: formação do jato supersônico, sua interação com atmosfera ambiente e finalmente sua interação com o banho metálico, tendo como conseqüência o refino da corrida. Neste trabalho foi proposto o estudo da configuração do bico da lança, na interação jato-banho metálico. O estudo será feito utilizando-se um modelo físico de convertedor LD em escala reduzida, a partir de relações de similaridade. O objetivo é estabelecer relações entre as geometrias de bicos da lança, e importantes variáveis no refino primário do aço, contribuindo para redução do tempo de sopro.Different technologies and new devices have been incorporated into BOF converters to increase their productivity in order to face the demand for steel production.Gerdau Barão de Cocais Steelplant also introduced new techniques and technologies into its BOF converter. These improvements led to a increase in the capacity of the BOF converter from 18 to 30 tons of liquid steel per heat, with the same basic lay-out.Despite this significant increase, Gerdau Barão de Cocais is still looking for new developments that could lead to further increases in the productivity of its BOF converter. The production of liquid steel in BOF converter involves a sequence of steps. The most important and time consuming step is the oxygen blow. Therefore, any reduction in thistime can have a significant impact on the BOF productivity. The study of oxygen blow is very complex and involves different phenomena, includingthe development of the supersonic jet, the interaction of the jet with the surrounding atmosphere and with the metallic bath, where the main reactions occur. In the present work, different alternatives for the design of the lance tip have been evaluated and the interaction of the supersonic jet with the metallic bath have been characterized. The investigation was performed using a physical model of Gerdau Barão de Cocais BOF converter

Effect of blow parameters in the jet penetration by physical model of BOF converter

It is important to know about the bath behavior to reduce the blow time and splashing in top of the converter. The target of this work is to compare works on the effect of twisted nozzle, flow and lance height in the jet penetration by visual inspection and by energy balance that consider number of nozzles, vertical and twist angles. In the present work, lances with twisted nozzle angles, normal lances and special nozzle shape were used to describe the effects of jet on bath. Jet penetration and level of splashing were also available. For the four nozzles, the best result to reduce spitting was obtained at the twist angle, hard blow and high flow. High flow, reduction in bath lance distance and lower nozzle angle promoted a higher penetration, but with bad results for the process. The energy balance showed to be a proper tool to promote adjustments in process

EOF cold model-study of bath behavior

The EOF reactor was developed in Brazil in the eighties with unique features. The preheating of scrap and distribution of injection points oxidizing gases and fuels make up these features. This paper aims to reproduce the behavior of the metal bath an EOF of 45 tons comparing their top three gas injection equipment: supersonic lances, atmospheric injectors and tuyeres. The lances and tuyeres promoted greater agitation of the bath with atmospheric injectors a great opportunity for improvement

A new concept of auxiliary fuel injection through tuyeres in blast furnaces developed by numerical simulations

The Injection of powdered materials in blast furnaces is a great option for reducing costs, increasing productivity and satisfy the environmental norms. Thus, this paper presents a study on the use of a flame stabilization system with rotation, designed to promote greater coal injection in the combustion zone, reducing losses and increasing the efficiency of the equipment. A physical model was used to evaluate scattering of pulverized fuel and is compared with numerical results in the same scale. In the second step, a combustion model was added to the numerical simulation, using dimensions of a real blast furnace. Fields like temperature, velocity and behavior of chemical reactions were analyzed. The results showed that double lances promote better particle injection when compared with simple lance for reduced material injection. The new injection system proposed, with swirl numbers of 0.12 and 0.24, promoted a better injection of both reduced material and temperature in the raceway zone. The swirl 0.24 showed superior performance when compared to other injection systems