Research On Control Method For Temperature And Air/Fuel Ratio Of Section Steel Reheating Furnace

This thesis has been carried out based on the reheating furnace of the Chongqing steel mill. The reheating furnace is a very important equipment of the steel mill. Its consumption occupies about 25 percent of the energy consumption of the steel industry. And the quality of steel which is processed by the furnace has a great influence on the following production line. Executing the effective control of the reheating furnace is important in today's increasing competition in the steel metallurgy.The characteristic of the combustion, such as, the great inertia, the nonlinearity, the long time delay, makes us very difficult to control the reheating furnace. So it is difficult to establish an accurate model of controlled object, and we can not control the reheating furnace with traditional technique. Fuzzy control technique does not need to establish an acute model for the problem solved, but it imitates the logical reasoning of person's brain, and can simplify many complicated problems. It has a great advantage in resolving the nonlinearity, indetermination problems. As a result, the fuzzy control technique is applied to reheating furnace control, and the research is made on these key problems including combustion control, temperature control and the algorithm of optimizing ration of air to fuel, which will make a positive drive on study and application of the reheating furnace.The author's contribution has been addressed in detail logically in this paper in the manner of the overall research process of the reheating furnace control system. Also, the author's design strategy and creativity has been given in this paper. Specifically, it includes:①This thesis has a profound research on the core technology of the reheating furnace control system-- the combustion mechanism and analyzed the relation of the combustion efficiency and the air/fuel ratio. Meanwhile, the control requirement to the critical technology of the reheating furnace has been set forth technically and the difficulty of the reheating furnace control system has been pointed out;②The temperature-combustion cascade control method has been adopted to control the temperature automatically. The different warm-up characteristics in every segment have been analyzed in detail. According to this, the temperature fuzzy controller has been designed. Then the method of self-turning factors has been applied to improve the flexibility of the basic fuzzy controller. Meanwhile, the method of improving the steady state accuracy has been given.③Based on the research of the...