Research On Energy Consumption Analysis And Optimization Of Small-Scale Reverse Osmosis Desalination Unit

The waste of pressure energy in the process of the traditional small reverse osmosis seawater desalination device leads to high energy consumption of the device,which has been the main reason for restricting its further serial production.This paper designs and studies the energy consumption analysis and calculation,process parameter optimization,energy recovery device and pressure lift pump for small seawater desalination plants.From the two aspects of process and energy recovery,the method of energy consumption of small seawater desalination device is explored,which reduces the energy consumption and operating cost of water,and improves the process performance and economic benefits of small seawater desalination plant.The main research contents and results of this paper are as follows:(1)Based on the principle of reverse osmosis seawater desalination,the theoretical energy consumption and actual energy consumption during reverse osmosis were analyzed and calculated.Taking the small reverse osmosis desalination plant model with a daily production capacity of 24 tons as an example,the energy consumption of each pump and energy recovery device in the reverse osmosis process is analyzed in detail,and the small reverse osmosis system is analyzed from the aspects of process and pipeline.In the middle energy loss,the operating energy consumption of the reverse osmosis process is 2.99 k W·h,the electric energy loss is 0.53 k W·h,and the pressure energy loss is 0.64 k W·h.(2)Designed a two-cylinder valve-controlled energy recovery device suitable for small reverse osmosis seawater desalination equipment,and completed the integration design of energy recovery device and pressure lift pump.Through simulation analysis,it is verified that the daily production water volume is 24 tons,the system recovery rate is 35%,the high pressure concentrated seawater pressure is 4.8 MPa,and the piston rod to piston diameter ratio is 0.2.At 5.0 MPa,the pressure and flow fluctuations of the reverse osmosis membrane are small,which meets the pressure demand of desalination seawater desalination.A small seawater desalination device model suitable for the energy recovery device was established,which reduced the energy loss of the energy recovery link and the pipeline from the perspective of integration.(3)Conducting an energy-optimization test for a 100-ton freshwater small-scale seawater desalination plant,and studying the energy consumption,water production flow rate and TDS parameter variation of the process under different actual conditions,respectively,in the influent water temperature gradient at 10 °C,15 °C,20 °C,25 °C,30 °C,the recovery values of the lowest ton water energy consumption in the actual operation of the device are 30.5%,33.5%,34.0%,35.5%,respectively.36.5%.At the same time,according to the water temperature in different seasons,working parameters that can reduce its energy consumption per ton of water are proposed.From the perspective of process parameters,a method to reduce the energy consumption of small desalination plants was systematically studied.