Variable nozzle height in AOD converter, step 2

Purpose and goal

The purpose was to investigate the practical conditions for varying the pressure at the nozzles in the AOD converter, and what effect this has on carbon refreshment. From plant experiments, experiments on a pilot scale and numerical and physical modeling, the sub-goals can be answered Yes, it is possible to move the nozzles without increased wear. Yes, it is possible to tilt the converter, moderately, without increased wear. Third question, "can carbon refreshment be improved by using variable nozzle height?" the answer is - perhaps, with larger variation in ferro-static pressure.

Expected results and effects

Of the two methods tested on an industrial scale, moving nozzles were the most promising technology. It was possible to implement practically in operation and it did not adversely affect the wear on the lining. It is difficult to see a clear connection for an improvement in carbon refreshment, possibly a minor improvement with the new position of the nozzles. This is also confirmed by the numerical models performed. It is possible that participating works will continue to have the nozzles at the higher position. Extended study of higher position of the nozzles is required for full effect.

Planned approach and implementation

In this project the practical possibilities to move the nozzles in the converter, as well as what impact such a change will have on the process, was investigated during an entire campaign. Furthermore, numerical methods as well as pilot plant experiments was used to answer if a higher position of the nozzles will yield a more efficient process. Finally, the possibility to lower the bath height by tilting the converter was investigated. Three different methods were used in order to reach the goal: 1.Numerical and physical modeling. 2.Pilot plant lab experiments. 3.Full scale plant trials.