Hybrid System Modeling And Coordinated Optimization Control Of The Blast-Furnace Hot Blast Stove

Blast furnace ironmaking production is one of the core procedure on the upstream of iron and steel industry process flow. Hot Blast Stove is the key aspect of energy consumption in the entire blast furnace ironmaking process. Building the effective model and control scheme for hot blast stove is focus of improving its operating efficiency and saving energy. Currently, in China, hot blast stove air temperature is below the world average level. The study of modeling for hot blast stove is lack and the control is mainly manual. So, the control effect more likely dependent on the experience of operating engineers. To solve these problems, this thesis presents a hybrid system modeling and coordinated optimization control method. The study for modeling and optimization control of hot blast stove is based on its industrial process. The subspace identification method has been used as well as the mixed logic dynamic modeling method and model predictive control method. This method has the advantage of more closely reflect the real working conditions of the hot blast stove and more reasonable control of it.The main content of this thesis includes the following aspects:1. Analyzing and processing mechanism model of hot blast stove. Using subspace identification method to identify the industrial processes of On-Gas Cycle and On-Blast Cycle of hot blast stove respectively based on its mechanism model. Then the state space model of the two industrial processes is get. The importance of identification method is illustrated and the identification result of hot blast stove is analyzed.2. Proposed hybrid system model for hot blast furnace based on mixed logic dynamic modeling. Designed mixed logic dynamic model establish programs for hot blast stove system using state space model of the two industrial processes. Get the standard form of the mixed logic dynamic model for hot blast stove.Described the hybrid system model using HYSDEL language and analyzed the simulation result of this model.3. Proposed coordinated control method for the hot blast stove industrial process based on its mixed logic dynamic model. Used variable time blast strategy. Designed the control methods for two industrial processes respectively. Used Model Predictive Control method for On-Gas Cycle and used mathematic model to calculate the volume flow of the bypass valve in order to ensure the stability of hot blast temperature. The switch method of the two industrial processes is illustrated. Finally, the simulation result of it has been compared with the traditional control method, indicating the feasibility, reliability and efficiency of the proposed control scheme.