Design And Optimization Of Water Utilization Network For Chemical Engineering Process

With the rapid development of economy, water resources in China are scarce year by year and environmental problems are increasingly serious. Chemical process industry is the most important water resource consumer and the primary source of waste water. Whether the water utilization network is reasonable or not will decide the water utilization cost of enterprises and the influence on environment. Consequently, the design and optimization of water utilization network is very significant.Since 1980s, the design and optimization of industrial water utilization network is increasingly taken seriously. In the thesis, the recent research progresses of water utilization network are summed up. The application methods of Mass Exchange Network are analyzed so as to find some key problems in this field at present. My major research work is shown as follows.First, the thesis analyzes the three basic methods to design water utilization network: source-sink, water pinch and mathematical programming method and introduces the approaches to combine source-sink curve to water pinch figure. The general superstructure model of water utilization network is built. The source and sink and water pinch figures for the same example are drawn respectively to calculate by them and the same results are obtained. The results show that the three methods have their own advantages. It will be helpful to obtain better results to integrate the three methods.Second, the superstructure model of water utilization network of multiple source-sink relationship is analyzed by using source-sink relationship as the constraint condition. The mathematical programming model based on source-sink relationship is built through introducing source-sink matching adjustable factor, z_i,j. The model is solved by regress linear programming method. The water utilization network with optimal engineering property is calculated and qualitatively screened out by mathematical programming method on the premise of using minor fresh water to guarantee the designed network optimum. Therefore, the common problems of mathematical programming method such as no exclusive solution, poor efficiency and difficulty in operation are solved.Third, the integrated optimization system of water utilization network with friendly interface is developed by mathematical programming model based on source-sink relationship and MATLAB software with powerful functions in numerical calculation and engineering computation. The system with mathematical programming method as the core integrates source-sink and water pinch figures and realizes the combination of water pinch technique and mathematical programming method. It is proved by calculating the example that a better solution than that in other literatures is obtained.Eventually, the industrial applicability of the developed system is determined by applications in petrochemical and food industry. The results show that the goal to improve the design efficiency of industrial water utilization network is achieved through the developed integrated optimization system. The system that needs just simple operation promotes the application of water network optimizing technique in practical water saving project.