Development And Simulation Of Solar-based Multistage Flash Evaporation Desalination Device

Nowadays,with the acceleration of the social modernization process,the growing demand for fresh water,but it is faced with the lack of fresh water.Seawater desalination technology is the main way to solve the problem of water shortages.However,the conventional desalination methods need to consume large amounts of fuel or electricity.In the fossil energy shortage and the burning of fossil fuels causes serious pollution to the environment today,using new energy is the optimal choice of desalination technology.Solar energy is one of the renewable energy sources.In recent years,the development of heat-collecting technology in middle and high temperature has become more and more mature.Therefore,it can be used to provide heat for desalination of seawater.In this paper,a solar multistage flash desalination system for solar energy is designed and simulated.The main research contents and conclusions are as follows:(1)Designing a small solar multistage flash desalination system.Calculating the average daily four seasons of solar collector receives the amount of solar radiation by using parameters of latitude,solar constant,declination angle and so on.Introducing a simple calculation method of the multistage flash determined parameters that required in the process.Furthermore,the structure of the flash chamber and its main components is designed.These provides a new thought to analyze small desalination system.(2)By building dynamic model for preheater in the flash room.The response of the outlet temperature is analyzed when the three parameters of the inlet brine flow,temperature and flash steam heating are disturbed.In the simulation computation of MATLAB software,it can be found that the inlet brine flow disturbance had the greatest influence on outlet water temperature,flash steam and heat disturbance impact times,inlet brine temperature disturbance least affected.The efficiency of the system can be improved by means of increasing the temperature disturbance of inlet brine and the heat disturbance of flash steam,reducing inlet brine flow disturbance.(3)For studying the specific process of the flash and analyzing the influence on flash performance when flash parameter changes,the paper adopted two kinds of simulation software of Aspen Plus and FLUENT comparative analysis.The result errors is less than 5%,thus it is reliable.Through the analysis can be concluded that with the rising of top temperature,the flash and PR increases,it improves the operation efficiency and economic performance of the device.When observed the curve,the extent of increasing is reducing.Considering the comprehensive factors,the system that is designed the best top temperature is 80?.Keeping the top temperature unchanged,the inlet brine flow is changed,the flash evaporation increased with the increase of the inlet brine flow,while the PR remained the same.Therefore,it can be concluded that by increasing the inlet brine flow,the flash evaporation can be increased,but the operation efficiency and economic performance of the device can not be improved.