Question

Example 7. Reverse Osmosis is used to treat 1.31 m/s of seawater at 293 K containing 3.5 wt% dissolved solids to produce 0.44 m/s of potable water with 500 ppm of dissolved solids. The feed-side pressure is 138 bar, while the permeate pressure is 3.4 bar. A single stage of spiral-wound membrane is used. If the total membrane area is 0.1 km², estimate the water permeability and the salt rejection.

Answer 1

solle Given that. Q-1131 m3/s; Acolkm? 20:1416€m? - Permeade side pressure drop=34 bus = 3:4 bois Feed side pressure = 138 bar. :: The Applied Pressure differential in COP) = 138-34212401 AP = 13616 bar) Assumption's As The Density of both the feed and the permeate is same as water density 1000 kg/m3. Dissolved. Nad gives 2ions pel molecule. Hence the Bulk feed scelt concentration is GSF = 0.035x2x1000 =Roxio 3X163 58.5 585 x Göt - = 1:1966 kmal mo ::SF = 1.1966 kmolim3] 6% matic Pressure Exerted by feeding I = 8314 X 298 x 1.1966 ~) 29-64 61 bal 100 [p = 29.6461 bas

Permecde Salt concentration in Csp =00005 X2X1000 58.5 - TO 04x104 1.0.0171 58:55 -585-0017 Ilham ..(p=0.0177k mollm3] Similarly, Permeate giver p=0.42351 bal 07 - 29.6461 -0.42351 - 29.22 bar AP - AIT = 134.6-29:22 = 10538 bas Trans - membrane flunk of water is Q = 4p x A (AP-07). . where (p= water per meability. ..(p= @ 1 . (AP-DITYA = 1-31-644 - 0.97 | |e533 xo (xles lo5 38 x10 9741002 x 105 x 10² - = 8.256xron 10538 T&p=8256x10=8]

Salt Rejection is sp=1-02 - 0.0035-0.0005 -|-0.0005 0.0035 0.0035 -0.0030 50.9857 0.0035 Hence salt Rejection is 8-9857 (8) 98.57%