Seawater reverse osmosis design

B. Penate, L. Garcia-Rodriguez, Current trends and future prospects in the design of seawater reverse osmosis desahnation technology. Desalination 284 (2012) 1—8. 

T.M. Missimer, R.G. Mahva, M. Thompson, W.S. Manahan, K.P. Goodboy, Reduction of seawater reverse osmosis treatment costs by improvement of raw water quahty innovative intake designs, Desal. Water Reuse 20 (3) (2010) 12-22. 

It is required to design a reverse osmosis unit to process 2500 mVh of seawater at 25°C containing 3.5 wt% dissolved salts, and produce purified water with 0.05 wt% dissolved salts. The pressure will be maintained at 135 atm on the residue side and 3.5 atm on the permeate side, and the temperature on both sides at 25°C. The dissolved salts may be assumed to be NaCl. With the proposed membrane, the salt permeance is 8.0 x 10 m/h and the water permeance is 0.085 kg/rn-.h.atrn. The density of the feed seawater is 1020 kg/m ( of the permeate, 997.5 kg/nv and of the residue (with an estimated salt content of 5 wt%), 1035 kg/rnc Assuming a perfect mixing model and neglecting the mass transfer resistances, determine the required membrane area and calculate the product flow rates and compositions. 

In Example 18.6, a reverse osmosis unit was designed to desalinate seawater based on provided data. It is required to rate an existing reverse osmosis unit, to determine its product rates and compositions. Data such as permeances, pressures, solution properties given in Example... 

An example of reverse osmosis seawater desalination for industrial purposes is the system installed in a thermoelectric power plant in Venezuela in 1980.17 The original segment of the plant is designed to produce 800,000 GPD of boiler feedwater and potable water. A process flow diagram for this system is shown in Figure 4.18. 

Applications for FT-30 membrane have appeared in all reverse osmosis fields from seawater desalination to home tapwater systems operating on line pressure. At this date, it is the only commercial reverse osmosis membrane other than cellulose acetate that has specific FDA approval for food contact usage.63 Versions of this membrane, manufactured under license to FilmTec, are available in tubular form (ZF-99, Patterson Candy International) and plate-and-frame design (HR-95, HR-98, De Danske Sukkerfabrikker).64 65... 

Pohland HW, Seawater desalination and reverse osmosis plant design. Desalination 1980, 32,157-167. 

While membrane processes have infiltrated many process schemes, prohahly the most extensive replacement has been in the area of water treatment. For example, reverse osmosis has largely replaced distillation/evaporation for the production of drinking water from seawater [41,42]. Clearly, with the right mix of material properties, efficient process designs, and economic drivers, energy-efficient membrane processes can replace conventional thermally driven separation processes. Later in this chapter, desalination will be a featured example. 

To overcome the problems of cellulose acetate membranes, many synthetic polymeric materials for reverse osmosis were proposed, but except for one material, none of them proved successful. The only one material, which could remain on the market, was the linear aromatic polyamide with pendant sulfonic acid groups, as shown in Figure 1.2. This material was proposed by DuPont, which fabricated very fine hollow fiber membranes the modules of this membrane were designated B-9 and B-10. They have a high rejection performance, which can be used for single-stage seawater desalination. They were widely used for mainly seawater or brackish water desalination and recovery of valuable materials such as electric deposition paints, until DuPont withdrew them from the market in 2001. 

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