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

摘要-RAMIREZ-9816804电弧炉炼钢在美国的使用量继续增加，目前的年产量估计在6300多万吨以上。长期以来，钢铁业一直以其对这个国家空气污染的贡献而闻名。钢铁生产商的减排进展缓慢，主要有两个原因：一是需要维持或提高目前的产量水平，二是对炼钢过程缺乏了解和控制。电弧炉拥有由液态(钢液)、炉渣(金属氧化物)和气体组成的三相系统，三者之间发生传质和换热。熔炉操作或控制，包括喷碳、氧气喷枪、燃烧器操作和空气渗透。这些控制用于在所要求的温度下生产适当等级的钢水。PI已经开始开发由熔化、平衡化学和材料平衡子模型组成的电弧炉动态模型。电弧炉模型包括工业熔炉中涉及的所有炉子操作。对炉子控制最大限度地减少一氧化碳排放的初步调查表明，该系统对喷碳和燃烧器氧气控制极其敏感。这些结果对改善加热炉的性能，包括对环境的影响和能耗都是很有希望的。在包括两家钢铁生产商在内的四家工业公司的合作下，研究人员计划进行一项为期三年的研究计划，其中包括模型验证和校准、在模型中添加NOx化学，以及使用动态规划和变分法对过程进行动态优化。这涉及到环保局的常识倡议，旨在为钢铁行业寻找更好的环境生产方法。研究的最终结果将是一个闭环最优控制系统，可以在保持盈利的同时将环境影响和能源消耗降至最低。该项目将导致电弧炉的运营政策，通过在源头最大限度地减少空气污染物的产生来防止污染。

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.