Research And Implementation Of Advanced Computer Control System For Stepped Regenerative Reheating Furnace

Reheating furnace is a very important equipment in the steel mills, and it is also one of the top energy users in the production line. So its a very important research field that how to reduce their energy consumption. Regenerative reheating furnace is a new kind of furnace. It can produce more steels of higher quality but with less energy. However, because of its strong coupling, multi-variable, time-varying, pure hysteresis, non-linearity, large inertia and some other characteristics, its not very easy to establish a real, stable and accurate model, which cause great difficulties in the control. So experts and researchers engaged in industrial control all around the world are working hard on the control strategy, expecting to develop more advanced control technology.This paper is based on the transformation of the No.1furnace of the3500production line in Jigang medium steel plate plant. The No.1furnace was a non-regenerative pusher type furnace. Because of its long working hours and its own limitations, it can no longer meet the needs of the production. In addition, the combustion control, furnace pressure control are performed manually, so it is difficult to achieve precise control, which cause parameter fluctuations and result in the production of billets of poor quality. For these reasons, we decided to transform it into regenerative reheating furnace and design a suitable control system. The main tasks include the following sections.Firstly, we had a comprehensive analysis of the production process of the regenerative reheating furnace. Combined with the analysis of the combustion condition, we did a research on the control system and find some problems that need to be solved. After that we had a detailed research on the control theory and proposed the control strategies of fuzzy PID method and improved cross-limiting dual method to make good control of the combustion process, chamber pressure, vaporization cooling system and the exchange system. In addition, the electrical control system was also being studied and detailed control method was proposed. A stepper system was designed, including the control of installing steel, walking beam, steel doors and some other parts. The control system is associated with the heating state of the furnace in order to heating uniformly and produce better steel. After that we designed the overall structure, including the PC monitoring software and the lower position machine control software. It can also be devided into two parts, the combustion controls and electrical control. Finally, the paper analyzes the overall operation of the system, and made a few points that still needed to be improved.Actual production line application results show that the design of regenerative reheating furnace combustion control and electrical control systems can be stably operated and can achieve the expectation. Besides, it can also produce better billet steel for the next procedure, thus improve the pass rate. At the same time, the enterprise can save large amount of energy and reduce the cost, then achieved the purpose of energy saving and consumption reduction.