| With the rapid development of urbanization,population growth,global climate change and the change of economic situation,the shortage of freshwater resources has become a major issue of common concern in the world.Seawater desalination is an important technology of water resources increment,which can be used as an important supplement and strategic reserve of water resources.Seawater reverse osmosis technology is becoming the mainstream technology of seawater desalination project in the world.Generally,the cost of electricity consumption in reverse osmosis seawater is about 1/2 ~ 2/3 of water production costs,and the energy consumption of the reverse osmosis desalination project depends mainly on the high pressure water supply system,in which the high pressure pump is the main energy consumption equipment of the high pressure water supply system,so the running state of the high-pressure pump is the main factor affecting the cost of water production for reverse osmosis desalination.Therefore,it is a great significance to study the energy saving operation of seawater desalination high pressure pump to reduce the energy consumption of high pressure water supply system.This research is supported by National Science and Technology Support Program "Research and Development of Desalination High Pressure Pump and Booster Pump"(2013BAB08B02)and "Development and Industrialization of High-efficiency High Pressure Pump and Booster Pump for Seawater desalination"(2014BAB08B01).In this paper,the high pressure water supply system with this high pressure pump is modeled and optimized.The research work mainly includes the following parts:The three-dimensional model of the whole flow domain of the high pressure pump was established and meshed,a computational fluid dynamics code was employed to simulated the performance of high pressure pump,it is shown that the predicted pump performance curves present good agreement with the experimental ones,indicating the numerical prediction of performance is correct and reliable.Based on this,the performance of the high pressure pump at different speed were simulated and analyzed.The characteristic curve of different speeds were fitted by the least square method,and the optimal operating area of the high pressure pump under different rotational speeds was obtained.The high-efficiency-area of the high pressure pump under different water supply pressure is determined.This provides an optimization basis for further determining the strategy of optimizing the operation of reverse osmosis seawater desalination high pressure pump.The mathematical model of the reverse osmosis seawater desalination membrane module was established.The influence of the parameters such as feed water temperature,total solid solution concentration and system recovery rate on the running characteristics of the membrane module under constant current and constant pressure was simulated and analyzed.The results showed that the feed water temperature and recovery rate had a great influence on the system water supply pressure,the system energy consumption and the salt content of the produced water,and had a great influence on the operating conditions of the reverse osmosis seawater desalination high pressure pump.Therefore,It need to consider the influence of temperature and recovery rate on the operating conditions of high pressure pump,which provides the basis for further determining the optimal operation scheme of high pressure water supply system for reverse osmosis seawater.Using MATLAB optimization tool to optimize the different schemes,it is shown that the electricity consumption of water production which considers the daily temperature change is lower than that of conventional operation.Considering the peak and valley price and the temperature is lower than that of conventional operation.In the optimization results of different schemes,the operating point of the high-pressure pump is always located in the large flow area.Therefore,the high efficiency point of the high-pressure pump should locate in the large flow rate;the high-pressure pump can maintain high efficiency during the operation.Therefore,in the design of high-pressure pump,the high efficiency point of the high-pressure pump should shift toward large-flow,in order to guarantee the high efficiency of the high pressure pump during operation. |
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