Computer Control for Continuous Reheating Furnace of Hot Strip Mill in Hot Charge Rolling

摘要

NKK developed a computer control system for hot strip mill reheating furnaces in hot charge rolling to reduce its energy consumption. This control system serves to ensure the optimal distribution of fuel to each zone in a sequential manner from the delivery side, and also to ensure an adequate temperature for the extracted slabs, especially for slabs in the unsteady heating area occupied by both conventional and hot charged slabs. A control model was devised to predict the slab temperature from the fuel input and atmosphere temperature of each zone, in consideration of the heat balance and thus determine the opitumum fuel input.This control system maintains accuracy through continual comparison of values from the model with actual values and modifying the fuel-flow accordingly. Furthermore an off-line simulator was also provided for the purpose of checking the control model. Application of this system to the NO.2 Hot Strip Mill in Fukuyama Works resulted in reduction of fuel comsumption by more than 100,000 Kcal/T in hot charge rolling.