DEVELOPMENT OF AN IMPROVED AUTOMATED CONTROL SYSTEM FOR CARBON INJECTORS OF AN ELECTRIC ARC FURNACE
Problem Statement (Relevance). At present, electric arc furnaces are widely used in modern metallurgy. Due to the energy intensity of these installations, a relevant task is to develop improved algorithms for controlling furnace units that reduce a share of costs for electricity and consumables in the cost of the final product. One of the ways for completing this task is to develop an improved control system for carbon injectors, which is the objective of this research. Methods Applied. In the study, the existing control algorithm for carbon injectors was analyzed using the example of the most common electric mode control system, ARCOS (Primetals Technologies, formerly Siemens VAI, VAI Fuchs, Vantron, Germany). The main disadvantages associated with the applied control parameter, as well as a general approach to determining the degree of arc shielding by foamed slag, are revealed. Taking into account the experience of previous studies, the authors proposed the technical solutions to eliminate the identified disadvantages. Originality. The paper describes new approaches to controlling the carbon material consumption, which are based on the use of the relative effective value of the total odd harmonics of arc voltages as a control parameter, as well as taking into account the rate of the current schedule of argon blowing. Result. A new control system for carbon injectors of the electric arc furnace has been developed to provide improved slag formation and the conditions for arcing by using an improved formula for calculating the slag coefficient, as well as an auxiliary system for automatic adaptation of arc lengths in case of insufficient slag formation. Practical Relevance. The use of a new injector control system makes it possible to ensure the optimal flow rate of carbon material in accordance with the melt blowing rate, as well as the possibility of complete shielding of the arcs with foamed slag at a given operating point. As a result, the cost of the final product is reduced by increasing the thermal efficiency of the arcs and decreasing the consumption of the carbon material.