BOF converter process model calculates optimal composition of charge materials and process gases for high productivity

MMK is upgrading three converters to increase productivity and improve blowing process efficiency. The focus of the order is on a new BOF (Basic Oxygen Furnace) converter model, which calculates the optimal composition of charge materials and process gases.

By upgrading three converters, PJSC Magnitogorsk Iron and Steel Works (MMK) in Russia intends to increase its productivity and make the blowing process more efficient.  The order includes the purposeful modernization of the automation system for the three converters, in particular the expansion of the basic automation system to include our BOF process model. Furthermore, the three converters, numbers 1, 2, and 3, will be equipped with a bottom-stirring system for inert gases (nitrogen and argon). The objectives of the upgrade are high process stability and high flexibility with regard to the varying input volumes of pig iron and scrap, as well as a reliable process flow that saves both time and material.

The existing basic automation system for the converter will be rounded off by the X-Pact^® Process Optimizer BOF as a process model for all converters. The BOF process model developed by SMS group can be adapted to special requirements and ambient conditions. The core of the BOF model comprises mass, energy and oxygen balance calculations. It works out the optimal composition of charge materials such as pig iron, scrap, ore, and slag formers, as well as process gases such as oxygen, nitrogen, and argon. The BOF process model reliably forecasts the critical points when the decarburization rate starts to decrease and the decarburization process ends. The result: high productivity and efficient process design with reproducible results.

A high hit rate in achieving set targets for the carbon content and tapping temperature leads to a significantly reduced reblowing rate and to consistently lower costs, e.g. thanks to minimized refractory wear. The cost-optimized calculation of the material additions helps to attain economical steel production.

The three 370-ton converters will also be equipped with new converter bottom-stirring systems with refractory lining, which we supply in conjunction with RHI Magnesita. New 3D laser profile measuring systems on all converters detect the wear of the refractory material and allow regular measurements of the refractory lining condition to be carried out. The scope of supply is supplemented by copper lance tips, which are optimized for homogeneous decarburization of the steel bath in combination with the new bottom-stirring system.