Maximização da eficiência de dessulfuração do gusa líquido num reator Kanbara.

This study has the objective to evaluate the metallurgical behavior of a Kanbara Reactor (KR) with respect to desulphurisation. In this reactor, the velocity of process depends strongly on the degree of dispersion of the desulfurizing reagent in the hot metal. Hence the influence of main operating parameters such as immersion depth, rotational speed, geometry, eccentricity of the stirrer on the dispersion rate of the desulphurizer was evaluated in a 1:7 scale physical model of a 315 ton industrial reactor. Smaller depth of immersion and higher speeds of stirrer rotation, increase the rate of particles dispersion; the greater the difference between densities of liquid and particles, smaller is the dispersion degree. These influences have been quantified. The eccentricity of the stirrer also influences a greater degree of dispersion and desulfurization seem to be related to the rate of splashing and projection of liquid, that should be kept to a minimum for safety reasons. Numerical simulations in respect of dispersion process were conducted with CFD (Computational Fluid Dynamics), software which resulted in data comparable to the physical model. Under industrial conditions, it is suggested that the coefficient of mass transfer presents strong dependence with velocity of rotation and eccentricity of the stirrer. Also the distribution of mass transfer coefficient values is not uniform throughout the reactor, and the highest values were found in the regions right ahead of the impeller blades. Despite of the obvious non uniformity of particle dispersion and mass transfer coefficients, data of 600 heats from Kanbara Reactor were analyzed using a macroscopic model, which assumes uniform spatial distribution of these variables. There is a good agreement between industrial results and those predicted by the model, so that it can be used for exploratory analysis.