Quick Direct Tap at United States Steel Corporation's Gary Works Q-BOP Shop

摘要

A Quick Direct Tapping (QDT) practice that eliminates the conventional turndown testing for temperature, oxygen content (ppm), and solid sample has been implemented for the three Q-BOP steelmaking furnaces at United States Steel Corporation's (U. S. Steel) Gary Works. To achieve QDT, a dynamic temperature and decarburization model was developed. Using the in-blow temperature measured by a drop-in (bomb) temperature sensor and the furnace waste gas temperature as the main inputs, the model provides the furnace operators with information on how much more oxygen to blow and how much coolant, if any, to add to achieve the aim carbon content and temperature. The model also provides, in real-time, the predicted temperature and carbon content of the steel bath. The drop of the temperature sensor into the Q-BOP furnace is automatically controlled by the Level I process control computer and is based primarily on the waste gas temperature. With successful operation of QDT systems on two furnaces, a third QDT system replaced the previously installed sublance system on the third furnace, due to cost and maintenance considerations of the sublance system. Since the full implementation of the practice on all three furnaces, the shop has achieved 97% QDT. Difficulties associated with the unique characteristics of the bottom blowing Q-BOP process experienced in the course of developing the QDT practice are described in the paper. Benefits realized from the QDT practice, such as improved safe working conditions, increased shop productivity, reduced flux consumption, and decreased heat costs, are also discussed.