The Process Simulation And Optimization For Circulating Cooling Water System Of Industrial

Water and energy are the substances on which human beings.At present,the reserves of freshwater resources and energy resources on the earth are decreasing.In addition,environmental pollution leads to the reduction of available freshwater resources and the non-renewability of most energy resources.The shortage of water resources and energy has become a major problem facing all mankind.The water consumption of the circulating cooling water system is large and the energy consumption of the pump in the system accounts for a large proportion of the total energy consumption of industrial production,in the actual industrial production.Therefore,it is important to research and optimize the circulating cooling water system for saving water resources and energy resources.Based on the research background of the circulating cooling water system in the distillation process of S company's 400,000 tons of Phenol-Acetone Project.The circulating cooling water system was analyzed and optimized by using the process simulation software Aspen Plus and the hydraulic model and water pinch technology.The research contents of this paper are as follows:Firstly,the field investigation and data acquisition of the circulating cooling water system of S company are carried out and the layout of the system is reproduced structurally.Through the simulation analysis of the pump network in the system.It is found that the pump network of the original system can not only meet the lift required by the maximum pressure head,but also higher than the maximum pressure head.At this time,the cooler with small medium pressure head in the system must close the opening of the outlet throttle valve,which increases the local resistance of the pipeline.The hydraulic analysis of the pump network optimizes the main pump network of the circulating cooling water system,and achieving 33.7% power saving.In the water pinch analysis and optimization of the cooler network,the "temperature" is used to replace the "concentration" in the water pinch analysis method,and the limit composite curve and the limit water supply line under the condition of the outlet temperature limit are constructed.Two subsystems(cooler network 1 and 2)are extracted from the circulating cooling water system.The system is optimized according to the water pinch rule,and 36% of the fresh water can be saved by optimizing the water pinch point of the cooler network 1.The "pinch migration" method is used to solve the problem of no pinch point formation in the process of optimizing the water pinch point technology for the cooler network 2.The optimized network can save 20% of the fresh water.For the optimized cooler network which keeps the total head unchanged,because some coolers have been retrofitted in series.It is easy to cause the increase of resistance along the head and the change of the minimum pressure head of this part of pipeline.It is necessary to analyze the pressure distribution of the network after retrofitting to determine the impact of the change of the cooler head on the pump pressure head.In this paper,the step-by step optimization method is used to optimize the circulating cooling water system based on a production example,so as to realize the efficient utilization of energy and water resources of the circulating cooling water system.According to the structural characteristics of the parallel connection of each water network of the cooling water system,the whole circulating cooling water system is gradually optimized by the method of subsystem extraction,combined with the process simulation software and the optimization process is more convenient.