Research On Evaporative Cooling System Of Walking-beam Furnace And Its Control

Walking-beam heating furnace is one of the key equipments in hot rolling line.Since the1970s, as one advanced type of furnace, walking-beam heating furnace iswidely used in hot rolling line. it has many characteristics, such as fast heatingspeed, large production capacity, good temperature uniformity, less burning loss,good heating quality, flexible operation, transporting billet forward or backward orwithout advancing step by step etc. Fixed beams and moving beams all composedby steel pipes are called water beams together.A walking beam consists of a few fixed and moving beams. Their surface ispackaged by refractory insulating material. They, called water beams, are made ofsteel pipes through which cooling water is circulating. In the process of waterchanging into vapour, a lot of latent heat is absorbed and water beams gain fullycooling. The vaporization cooling medium is high temperature soft water. It can notonly avoid the water beam scale, reduce the probability of occurrence of billetblack printing and temperature difference, improve the heated billet quality,increase the furnace service life, but also has the advantages of saving water, steamenergy recycling.The steam drum is the core equipment of the vaporation cooling system.Taking a steel enterprise’s heating furnace as the background, the vaporizationcooling system’s static and dynamic characteristics is studied. three-parameterfeedforward-cascade control scheme is identified on the basis of the drum levelcontrol schemes with single, double, three-parameter, being analyzed, compared,researched respectively. By using the conventional PID controller andtwo-dimensional fuzzy controller, a fuzzy self-tuning PID controller is obtainedand three-parameter self-tuning fuzzy PID feedforward-cascade control system isdesigned.Matlab/Simulink is used to simulate the drum level control system comprehensively.Simulation results show that three-parameter scheme’s performance is far better thansingle and double-parameter scheme’s. Three-parameter self-tuning fuzzy PIDfeedforward-cascade control scheme makes drum level control system have quickresponse, small overshoot, smaller steady-state error, strong anti-interference ability and good robustness.