Temperature control for reheating furnace walking hearth type in heating curve up process

The slab reheating process for iron rolling to the small diameter wire in Ratchasima Steel Products Co., Ltd. factory (Nakron Ratchasima, Thailand) use the reheating furnace walking hearth type which control the temperature of the process about 1150-1200 Celsius (up to each zone) and consume time about 2 hours. The air fuel ratio control of this furnace is feedback control which use PID controller. The problems in the present are reducing production cost and increasing performance in energy consumption which most cost of the factory from in the slab reheating process. So the factory has the idea to change the energy source to the cheaper source such as nature gas, bio-gas etc and improve the performance of the temperature control of the reheating furnace in heating curve up process. Consequently the controller isn't suitable for the slab reheating process in the present then can't control the desired temperature and lose the energy. From the mentioned reason, we have to analysis and study to estimate the mathematical model of reheating furnace for design the controller. This paper present the mathematical model of reheating furnace walking beam type using system identification method to estimate the parameter of the mathematical model with the temperature response of slab reheating process and apply adaptive system to design the suitable input with the desire response of slab reheating process by consider to select the optimal process in terms of fuel economy and temperature response.