Research On Thermal Parameters Modeling And Control For Reheating Furnace

Reheating furnace is one of the important equipment in steel rolling industry, which is used to heat steel billets, and meets the needs of environmental protection and energy conservation as far as possible. Considering the complex process of reheating furnace, which has the characteristics of time-varying, nonlinear, lagging behind the major, it is of much practical meaning to do research on the thermal parameters modeling and advanced control strategy of reheating furnace to realize its optimizing operation.The research was based on the background of regenerative reheating furnace. Firstly, this thesis analyzed the conduction heat transfer, heat convection and radiation heat transfer among the steel billets, fender and furnace gas in reheating furnace, and calculated how much energy the three substances converted in synthesized heat exchanging process.Secondly, on the basis of heat transfers in furnace and ternary model method, this thesis set up simplified models to solve gas temperature. And the model of temperature field in slabs was established by the laws of conduction heat transfer, heat convection and radiation heat transfer, and the temperature model of fender was got. Then the furnace temperature was controlled by the use of conventional PID algorithm and fuzzy self-tuning PID control algorithm, respectively. And the control results were analyzed and compared.Finally, the thesis analyzed the mechanism model of pipeline pressure characteristics. And it was found that there were many factors that could affect the pipeline pressure downstream of the control valve, such as the valve opening, pipeline pressure upstream of the valve, quantity of flow, discharge coefficient and fluid density and so on. And these factors mentioned above were interactional and interacted as parameters, so it was difficult to set up the mechanism model of pipeline pressure. Therefore, the thesis used data-based methods to establish a BP neural network model of pipeline pressure. And then the feedforward-feedback control method was used to control pipeline pressure in case of upstream pressure of the pipeline while being distracted, and the control results were satisfactory.