Method and system for performing reverse osmosis with integrated pump storage

Abstract

A reverse osmosis system includes a first pretreatment system and a fluid source located below a reservoir. A first membrane housing has a reverse osmosis membrane therein. A first turbocharger includes a first pump portion and a first turbine portion. The first pump portion receives feed fluid from the first pretreatment system, pressurizing the feed fluid and communicates the feed fluid to the feed fluid inlet. The first turbine portion receives brine fluid from the brine outlet. The system further includes a second and third turbocharger. A second turbine portion and the third turbine portion receive brine fluid from the first turbine portion. Second feed fluid is communicated through a booster pump, a second pretreatment system, and second pump portion to increase a pressure of the second feed fluid. The second feed fluid is communicated to the third pump portion which communicates the pressurized second feed fluid to the first pump portion.

What is claimed is: 
     
         1 . A reverse osmosis system coupled to a fluid reservoir having a surface, said system comprising:
 a pretreatment system fluidically coupled to the fluid reservoir disposed a first predetermined distance below the fluid reservoir;   a membrane housing comprising a reverse osmosis membrane therein, said membrane housing comprising a feed fluid inlet, a brine outlet and a permeate outlet; and   a first turbocharger comprising a first pump portion and a first turbine portion;   said brine outlet coupled to a first pipe directing brine fluid to the first turbine portion;   said first pump portion in fluid communication with the feed fluid inlet;   said brine outlet coupled to the first turbine portion.   
     
     
         2 . The reverse osmosis system of  claim 1  wherein the first predetermined distance is about 40 m below the surface of the fluid reservoir. 
     
     
         3 . The reverse osmosis system of  claim 1  wherein the first predetermined distance is about 30 m below the surface of the fluid reservoir. 
     
     
         4 . The reverse osmosis system of  claim 1  wherein the first predetermined distance is between about 30 m and 40 m below the surface of the fluid reservoir. 
     
     
         5 . The reverse osmosis system of  claim 1  wherein the first turbocharger is located a second predetermined distance below the surface of the fluid reservoir, said second predetermined distance is between about 300 m and 350 m below the surface of the fluid reservoir. 
     
     
         6 . The reverse osmosis system of  claim 1  wherein the first turbocharger is located a second predetermined distance below the surface of the fluid reservoir, said second predetermined distance is between about 200 m and 400 m below the surface of the fluid reservoir. 
     
     
         7 . The reverse osmosis system of  claim 1  further comprising a pump-turbine fluidically coupling a fluid source to the fluid reservoir. 
     
     
         8 . The reverse osmosis system of  claim 1  further comprising a motor coupled to the first turbine portion operating the first turbine portion at a motor speed to increase a pressure of a feed fluid provided by the first pump portion. 
     
     
         9 . The reverse osmosis system of  claim 8  wherein the motor speed is based on a salinity of the feed fluid. 
     
     
         10 . The reverse osmosis system of  claim 8  wherein the motor speed is based on a temperature of the feed fluid. 
     
     
         11 . The reverse osmosis system of  claim 8  wherein the motor speed is based on an age of the reverse osmosis membrane within the membrane housing. 
     
     
         12 . The reverse osmosis system of  claim 8  further comprising controlling the motor speed in response to a flow rate of the feed fluid to the first turbocharger. 
     
     
         13 . A method of operating a reverse osmosis system coupled to a fluid reservoir and a fluid source located below the fluid reservoir, the system comprises a pretreatment system, a membrane housing comprising a reverse osmosis membrane therein, said membrane housing comprising a first feed fluid inlet, a first brine outlet and a first permeate outlet, a first turbocharger comprising a first pump portion and a first turbine portion, said method comprising:
 communicating fluid to the fluid reservoir from the fluid source through a pump-turbine;   communicating the fluid from the fluid reservoir through the pretreatment system to the first pump portion to form feed fluid;   pressurizing the feed fluid at the first pump portion;   communicating the feed fluid to the feed fluid inlet through the first pump portion; and   communicating brine fluid from the first brine outlet of the membrane housing to the first turbine portion to operate the first pump portion.   
     
     
         14 . The method of  claim 13  wherein communicating the fluid from the fluid reservoir through the pretreatment system to the first pump portion to form the feed fluid comprises communicating the fluid from the fluid reservoir through the pretreatment system located about 30 m and 40 m below a surface of the fluid reservoir. 
     
     
         15 . The method of  claim 13  wherein communicating the fluid from the fluid reservoir through the pretreatment system to the first pump portion to form the feed fluid comprises communicating the fluid from the fluid reservoir through the pretreatment system to the first pump portion located between about 200 m and 400 m below a surface of the fluid reservoir. 
     
     
         16 . The method of  claim 13  further comprising operating the first turbine portion with a motor operated at a motor speed to increase a pressure provided by the first pump portion. 
     
     
         17 . The method of  claim 16  further comprising controlling the motor speed in response to a salinity of the feed fluid. 
     
     
         18 . The method of  claim 16  further comprising controlling the motor speed in response to a temperature of the feed fluid. 
     
     
         19 . The method of  claim 16  further comprising controlling the motor speed in response to an age of the reverse osmosis membrane within the membrane housing. 
     
     
         20 . The method of  claim 16  further comprising controlling the motor speed in response to a flow rate of the feed fluid to the first turbocharger.