More Than A Dozen Intelligent Decoupling Of The Process Of Asymmetric Coke Oven Gas Gathering And Coordination And Control Algorithms

Coke is the main raw material in the metallurgical industry. In the coking process, large amount of by-product gas will be generated from coke ovens, and the process of recycling by-product gas is called gas collecting process. It is an important link in the iron and steel production, which not only saves energy but also reduces environmental pollution. The stability of gas collectors' pressure directly influences the gas quality, the life-time of ovens and the producing environment. Therefore, it is a vital significance for the iron and steel enterprise to study on the control of gas collecting process of multi asymmetrical coke ovens.The gas collecting process of multi asymmetrical coke ovens is a highly complex industrial process. Its characteristics of multivariable, strong coupling, asymmetry and nonlinearity, time-varying and hard in modeling are the major difficulties in the control of gas collecting process, so it is hard to achieve effective control using traditional control methods. Based on profound researching on the characters of gas collecting process, this paper introduces the concept of coupling degree, and proposes an intelligent decoupling and coordination control algorithm based on it, thus realizes hierarchical decoupling control of gas collecting process by incorporating advanced techniques such as adaptive fuzzy control, expert control and intelligent decoupling control.In basic control level, fuzzy controller and PID controller for single gas collector are adopted through analyzing the characteristics of gas collecting process, and the outputs of fuzzy controllers are adjusted using adaptive control algorithm for special working conditions. At the same time, feed-forward expert control algorithm is adopted to compensate strong perturbation. In decoupling control level, the coupling degrees of multi gas collectors are calculated using law of probability and statistics on the base of operators' experiences and characteristics of gas collecting process. Then the gas collectors of multi asymmetrical coke ovens are distributed into strong-couple level and weak-couple level by coupling degrees, and fuzzy decoupling control algorithm based on expert rules is adopted according to different coupling intensity of each level. Thus the decoupling control of gas collecting process is realized by hierarchically eliminating the coupling of each level. In coordination control level, coordination controller is designed to optimize the pressure setting value of each gas collector aiming at abnormal conditions, and butterfly valve controller is developed to adapt to the characteristics of butterfly valve so as to enhance the control quality.The control algorithm has been applied in gas collecting processes of three coke ovens in an iron and steel enterprise. The actual running result shows that the control algorithm is simple, feasible and reliable, which is also easy to expand and has strong anti-disturbance ability. The control algorithm has realized the pressure stability of the gas collecting process of multi coke ovens even when the mathematical model is difficulty to obtain. It has created great economic and social benefits; meanwhile, it has also lessened the labor intensity. In a word, it provides an efficient method for the decoupling and coordination control of the gas collecting process of multi asymmetrical coke ovens.