No abstract

Samarco produces high quality iron ore pellets processed in straight grate furnaces. This process is essential in order to obtain adequate mechanical strength to the pellet transportation and operation in the reduction reactors. All mechanical properties of the agglomerates are obtained during the stage of firing where the slag and sintering bond happens, thus it is a decisive step to improve the pellet quality. Therefore, the velocity distribution of gas flow within this zone must have homogeneous and even velocity distribution. Hence, it was developed a mathematical CFD model to characterize the gas flow in the burning zone, applying the equations of conservation of momentum, mass and energy and an uneven flow distribution was identified and the gas velocity analyzed and validated through experimental data. On the other hand, on the present paper, an improved firing zone burner were developed and industrially implemented in a way to mitigate the uneven flow pattern detected aided by CFD. Different burner designs, based on CFD analysis, were experimented in order to succeed on the aggressive condition. The combustion was investigated and burner efficiency evaluated and compared with the simulation purposed.

ResumoO processo de pelotização consiste na aglomeração e posterior tratamento térmico das pelotas, ajustando as propriedades químicas e mecânicas para o transporte ao reator siderúrgico. A otimização e aperfeiçoamento do processo no forno pode ser realizado experimentalmente utilizando um pot grate. Trata-se de um equipamento no qual uma carga de pelotas cruas é submetida a condições similares às encontradas no processo industrial. Contudo, um projeto de experimentos em um pot grate pode levar semanas. Além disso, alguns parâmetros como: taxas das reações e balanço de energia são difíceis de serem monitorados. Tendo em vista isso, o presente trabalho buscou desenvolver um software de simulação para avaliar o comportamento das pelotas em um pot grate de maneira rápida e prática. Os resultados mostram uma interface amigável para a avaliação da temperatura de pelota, umidade da água, queima do carbono e balanço de energia. Os modelos implementados foram comparados e validados com trabalhos publicados na literatura. O modelo também serve como uma ferramenta de Projetos e Experimentos no Pot, uma vez que permite testes mais rápidos e de custo mais baixo. Palavras-chave: Pelotização; Pot grate; Software. INTERFACE DEVELOPMENT FOR NUMERICAL ANALYSIS OF FIRING PELLETS IN THE POT GRATE SAMARCO AbstractThe pelletization process consists in balling and subsequent thermal treatment of the pellets by adjusting the chemical and mechanical properties for shipping to ironmaking. The optimization and process improvement in the furnace can be performed experimentally using a pot grate. This is a facility in which a charge of raw pellets is subjected to conditions similar to those observed in the industrial process. However, an experimental design in a pot grate can take days. In addition, some parameters such as: rates of reactions and energy balance are difficult to monitor. Based on that, the present study aimed to develop a simulation software to evaluate the behavior of pellets in a grate pot quickly and conveniently. The results show a friendly interface for the evaluation of pellet temperature, water moisture, carbon burning and energy balance. The implemented models were compared and validated with published studies. The model also projects and serves as a tool in pot experiments, since it allows for faster testing and lower cost.