Effect of Bottom Nozzle Arrangement on Splashing and Spitting in Combined Blowing Converter

Abstract

Wear of refractory lining, skulling of converter cone and metal losses were studied by splashing and spitting measurements in physical model during combined blowing. The aim of the present study was to determine the effect of the bottom nozzle arrangement and lance height as far as on harmful splashing and spitting in combined blowing converter are considered. The investigation has concentrated mainly on the initial period of blowing.
According to the model tests, total splashing on the converter walls increases as a function of number of bottom nozzles (with increase of total gas flow rate) both initial and final period of blowing. At the initial period of blowing, combined blowing produces maximum measured total splashing and large reaction area as a form of droplets. The nozzles arranged at the centre of the vessel increase metal losses and skulling of the converter cone especially with lowered lance height. The introduction of outside of lance cavities arranged bottom nozzles decreases metal losses and skulling of converter cone compared to the top lance blowing at final period of blowing. The usage of high lance height and several bottom nozzles accelerate wear of the refractory, especially at the knuckle area and charge pad area. It is possible to reduce splashing to the knuckle areas with certain lance gaps by positioning bottom nozzles directly between the cavity and knuckle area with remarkable (approximately 30-40 %) overlap.