Study And Optimization Of The Furnace Automatic Control Model System Of Pangang 1450 Hot Stip Mill

There are few successful cases on the furnace combustion control model in China due to heat conduction presenting a very complex process. In this study, a furnace automatic combustion control model has been developed and optimized, which used in the two reheating furnaces of Pangang 1450 Hot-strip Mill. The furnace automatic combustion control model was successfully applied in the control system of reheating furnace of Pangang Group, and become a typical case for other iron and steel works.There are two parts in this study. The development of the furnace automatic control model system was induced in the first part, and the optimization method of the model was investigated in the second part. The development of the model was the cooperation outcome between the Panggang Group and Chongqing Iron and Steel Designing Institute. In this paper, the processes and the mathematics model of reheating furnace was the main aspect of study. This furnace automatic combustion control model is composed of five moduels, such as charge moduel, recharge module, diapause module, cycle module and data filing-up module. The optimization of the model has been carried out by industrial testing and the setup of off-line model. In one hand, the actual temperate of slab was measured by black-box testing, and compared with the calculation results of model computation. As a result, the accuracy of the model computation has been validated, and the inappropriation of the distribution of heat load and the temperature difference between the interior and outerior side of the slab could be found. In the other hand, an off-line model of the reheating furnace has been set up and validated by off-line simulating method. At the same time, in combination with the industrial testing, the verification and optimization of the charge temperature calculation and model parameters, and the optimization of the self study model of discharge temperature module and pre-rolling model have been completed. The results showed that the model was running in an accurate state though the optimization.This control model system of the rolling reheating furnace has been built up and applied in actual production. The application ratio has been reached 100% in normal production. Also, a good effect has been obtained by the application of the combustion control model. The control technology of the cold charging, hot charging and combination of them under the different charging temperature has been improved. The unit consumption of coal gas has been decreased 11.8%. The oxidation inside of furnace has been controlled and the loss of oxidation decreased about 6.7%. The slab quality of heating has been improved greatly to cause the temperature difference of slab cross section at 23～28℃(average temperature about 25℃). The hit rate of discharging object temperate has been changed from less than 70% to more than 95% (increasing about 25%).