Chemical Process Simulation And Real-time(On-line) Optimization

By applying the real-time (or on-line) simulation and optimization (RTSO) in the chemical process industries (CPI), the greatest economic benefit arises from constantly driving the plant toward its optimum operating point. RTSO is the key part in transforming the basic process control into the computer integrated automation system for chemical process industries. It bridges the gap between advanced process control systems and plant management systems.Since 1970s, a large number of manpower and material resources have been put in this area in other countries and many excellent steady-state flowsheet simulation/on-line optimization softwares have been developed. In recent years, some foreign corporation popularized this technique in our country. As the price of RTSO project is raised continuously, our chemical industry faces a serious challenge. In order to develop our own RTSO software, systematic researches in RTSO for two important units-the general distillation and the fixed bed reactor in CPI are carried out in this dissertation. These researches are subsidized by the Ninth Five-year's national key project "Research and development of the commercial industrial on-line control and optimization package".The major contributions of this dissertation are stated as follows : The technique of the chemical process simulation and real-time optimization is systematically introduced meanwhile the advantages and disadvantages of different steady-state flowsheet simulation approaches are deeply analyzed. On the other hand, the structure, contents and key techniques of RTSO are discussed. Finally it is pointed out that the development for our own commercial real-time on-line simulation and optimization software is necessary and urgent, which can greatly increase the creative capacity and economic benefits. It is pointed out that the open-equation modeling based on the local property model (LPM) is the best modeling approach for RTSO. The LPM can efficiently improve the solution of the open-equation model systems. The general open-equation model for distillations based on the LPM with tray efficiency modifications for RTSO has been developed. Studies on the ethylbenzene distillation show that this model can simulate the scene data well, overcome the component discontinuous distribution with theoretic trays and satisfy the RTSO. This model will become the most important program of the distillation RTSO package.