Optimal Operation of Electric Arc Furnaces to Minimize the Generation of Air Pollutants at the Source

点击翻译按钮获取中文摘要

Abstract - Ramirez - 9816804 The manufacture of steel by electric arc furnaces (EAF) is continuing to increase in usage in the United States with current production estimated to be over 63 million tons per year. The steel industry has long been known for its contributions to air pollution in this country. The reduction of emissions from steel producers has been slow for two main reasons: the need to maintain or increase current production levels and the lack of understanding and control of the steel-making process. The EAF holds a three-phase system of liquid (molten steel), slag (metal oxides), and gas with both mass and heat transfer taking place amongst the three. The furnace operations, or controls, include carbon injection, oxygen lancing, burner operation, and air infiltration. The controls are used to produce the appropriate grade of liquid steel at a requested temperature. The PI has begun the development of a dynamic model of the electric arc furnace consisting of melting, equilibrium chemistry, and material balance sub-models. The EAF model includes all of the furnace operations involved in an industrial furnace. Preliminary investigations into the control of the furnace minimize carbon monoxide emissions have shown that the system is extremely sensitive to carbon injection and burner oxygen controls. These results show great promise for the improvement of furnace performance, which includes environmental impact and energy consumption. With the collaboration of four industrial companies, including two steel producers, the investigator plans a three year research program which includes model verification and calibration, the addition of NOx chemistry to the model, and dynamic optimization of the process using dynamic programming and the calculus of variations. This addresses the EPA's Common Sense Initiative toward finding better environmental production methods for the steel industry. The final result of the research will be a closed-loop optimal control system that can minimize environmental impact and energy consumption while maintaining profitability. This project will lead to operational policies for electric arc furnaces that allows for pollution prevention by minimizing the generation of air pollutants at the source.