1 Membrane modules 1.1 Gas Permeation A perfectly mixed gas permeation module is
ID: 524954 • Letter: 1
Question
1 Membrane modules 1.1 Gas Permeation A perfectly mixed gas permeation module is separating carbon dioxide from nitro- gen using a poly (2,6-dimethylphenylene oxide) membrane (Pco a 0.034 x 10-13 PN, 0.089 13 (STP) cm/cm28Pal). The feed is 20.0 mol% carbon diox- ide and is at 250 C. The module has 250 m2 of membrane. The module is operated with a retentate pressure of 5.5 atm and a permeate pressure of 1.01 atm. We desire a permeate that is 35.0 mol% carbon dioxide. The membrane thickness is l s 1.0 x 10-4 cm. Compute all the input and output flowrates and compositions. 1.2 Reverse Osmosis Compute the total membrane area necessary to produce 10 l/h purified water (0.03 wt% Naci) through a single stage Reverse osmosis separation of seawater (water 4 wt% NaC) if the feed pressure is 100 bar and the composition in the retentate stream is 7 wt%. The permeate stream is at ambient pressure (1 bar), all streams are at 25° C, and the osmotic pressure is well represented by the semiempirical expression 1.12 14.5 where T is the temperature in K, N is the total number of ionic species in solution, and ci is the concentration expressed in Imollij The asymmetric membrane used for the has a permeance of 1E-6 lm h-1 bar-1l How much is the salt rejection in this process? 2 Process Configurations 2.1 Batch 500 l of fruit juice are concentrated from an initial solid residue content of 0.05 kg/l to a solid-residue content of 0.2 kg/l through a batch microfiltration process.Explanation / Answer
Solution:
# 1.2 Reverse Osmosis
F = 10 lt/ h (0.03 wt% NaCl), P = 100 bar, purifies at 4 wt% NaCl, R = 7 wt%, T = 25 C = 298 K,
Pamb = 1 bar= 1 atm, R salt = ?
water flux is,
Nw = F*rho / A = (10*997) / 1 = 9970 kg water per hr. m2
Nsalt = Nw*c2/cw =9970 * (4 /100) / 997 = 0.4 kg solute NaCl per hr. m2
By using given expression we get osmotic pressure as,
pi = 2.3 bar
Salt rejection is,
R = (c1-c2) / c1 = (10-0.4) / 10 = 0.96
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.