A mixture of helium, oxygen, carbon dioxide, and nitrogen is fed to a perfectly mixed GP system with a poly (dimethylsiloxane) membrane at \(25^{\circ} \mathrm{C}\). Membrane properties are given in Table 19-2. Membrane active layer thickness is \(1.2 \mu \mathrm{m}\). Feed pressure is \(6.4 \mathrm{~atm}=\) retentate pressure. Permeate pressure is \(1.03 \mathrm{~atm}\). Feed is 0.6 mole \% helium, \(57.5 \mathrm{~mole} \%\) carbon dioxide, \(13.5 \mathrm{~mol} \%\) oxygen, and 28.4 mole \% nitrogen. Feed rate is 1.13 \(\mathrm{m}^{3} / \mathrm{s}\) STP.

a.* Find retentate mole fractions, permeate mole fractions, and membrane area (in \(\mathrm{m}^{2}\) ) for \(\theta=0.36\).

b. Find retentate mole fractions, permeate mole fractions, and \(\theta\) for membrane area \(=100.0 \mathrm{~m}^{2}\).

Transcribed Image Text:

Membrane Poly [1-(trimethylsilyl)-1-propyne] Poly (dimethylsiloxane) Poly (dimethylsiloxane) TABLE 19-2. Permeabilities of gases in Barrers in polymer membranes TC He H2 CO2 O2 CH4 N2 Ref - 28,000 7730 - 4970 DR 25 230 - 3240 605 - 300 N 35 - 4550 781 - 351 DR Poly (4-methyl pentene) Natural rubber Natural rubber Natural rubber Silicone rubber 25 100 25 23.7 90.8 99.6 17.7 - 93 32 - 8.0 N 6.12 N 25 153.0 - - 9.43 DR 25 31 49 131 24 30 8.1 G 25 300 550 2700 500 800 250 G Ethyl cellulose Polystyrene 25 53.4- 113 15 - 3.0 N 35 - 12.4 2.9 0.52 DR Polystyrene Polycarbonate Butyl rubber Butyl rubber 30 40.8 56.0 23.3 7.47 2.72 2.55 G 25 19 - 8.0 1.4 - 0.30 N 25 8.42- 5.2 1.30 - 0.33 N 35 - - 5.18 - - 0.324 DR Acetyl cellulose Cellulose acetate Nylon 6 Nylon 66 22 13.6 0.43 - 0.14 N 35 - 4.75 0.82 0.15 DR 30 0.53 0.16 0.038 - N 25 1.0 - PIM-1 (polymers of intrinsic porosity-ladder type) PIM-7 0.17 0.034 1300 2300 370 860 1100 190 0.008 G 12.5 a 92.3b R 62.1 42.1b R