Cascade Pressurized And Cutting Impeller Seawater Desalination System Flux Equalization Process

In recent years,reverse osmosis technology has been rapidly developed and widely used in seawater desalination,and has become the main technology of seawater desalination in the domestic and overseas.However,in the process of reverse osmosis seawater desalination,the distribution of water flux along the flow process is seriously unbalanced,that is,the flux ratio of the first and end components in the system is too large,and the problem has not been effectively solved.The imbalance of system flux distribution will lead to a series of problems,such as the unbalanced distribution of system pollution,the reduction of desalting rate and frequent cleaning of membrane elements.This phenomenon has hindered the development of reverse osmosis technology to some extent,and reduced the efficiency of reverse osmosis process system.At present,academics and engineering scholars at home and abroad have focused on membrane materials and membrane components for reverse osmosis seawater desalination systems,which are less involved in the system flux imbalance.In order to realize the flux equilibrium and controllable flux distribution of the desalination system,the system structure and the equilibrium process of the cascade pressure,cutting impeller and half impellers are put forward respectively.This study describes the mathematical models of four parts of the reverse osmosis membrane element,the cascade centrifugal pump,the cutting impeller and the half impellers in the desalination system,and integrate them into a mathematical model for the operation of the desalination system of the cascade pressure and cutting impeller.According to the model,the corresponding "system operation simulation software" is compiled,which forming a simulation environment for simulating and analyzing the operation condition of the desalination system.In order to facilitate analysis and comparison,this study assumes a specific system of series structure of water supply,water temperature,system recovery,average flux,element variety and process length.First of all,the difference of operation index between traditional seawater desalination system and cascade pressurized seawater desalination system is compared and analyzed.The data show that,under the condition of the "specific system",the flux equilibrium of the cascade pressure system can be greatly improved compared with the traditional seawater desalination system,but the distribution of the flux along the range is not reasonable.Secondly,the difference of operation indexes between cascade pressurized seawater desalination system and stepped pressure and cutting impeller sea water system is compared and analyzed.The data show that,based on the structure of the cascade pressure system,with the cutting impeller and the increasing half impeller technology,the controllable and decreasing distribution of the flux along the distance can be realized flexibly,and the ideal distribution of the flux along the system can be realized.The analysis shows that through the technology of cascade pressure and cutting impeller and so on,the distribution of the flux along the sea water desalination system is more balanced.Although the water energy consumption is increased,the water quality is improved.Thirdly,the influence of water supply conditions and operating parameters on the equilibrium of flux distribution in cascade pressurization and cutting impeller is analyzed.The results show that when the operating conditions of water supply temperature,water supply salt,average flux,system recovery rate or pollution degree change greatly,the flux distribution of the system will fluctuate under the original state,but it can still maintain high system stability and higher flux equilibrium.