answer7.doc 23KB Jun 05 2011 09:30:38 PM

Answers to Selected Odd-Numbered Exercises in

“Separation Process Principles” by

J. D. Seader and Ernest J. Henley

Chapter 7

7.3 Condenser temperature must be below critical temperature of -115o_{F for}

methane. Might operate column at a top pressure of 540 psia and a corresponding temperature of -130o_{F, using R-14 (carbontetrafluoride) refrigerant at -140}o_F.

7.11

Procedure (a) (b) (c)

1 63 94.5 53

2 67.2 100.8 49.5

3 68.8 103.1 48

4 67.2 100.8 49.5

5 78.3 117.4 34.2

Procedure 5 is best.

7.13 (a) 12.1 kg distillate and 17.9 kg bottoms. (b) 11 stages + partial reboiler

7.15 (a) Yes

(b) 46.2 kmol/h (c) 22 mol% benzene

7.l7 (a) (1) 1.04

(2) 14 mol% benzene (3) 43.9 moles distillate (b) (1) 2.22

(2) 10.5 mol% benzene (3) 46.2 moles distillate (c) (1) 7 mol% benzene (2) 48.3 moles distillate

7.19 Assuming a saturated liquid feed, condenser cooling water leaks in. No, 90% product can not be obtained.

7.25 73.8 kmoles

7.29 (a) 0.777 mol% ethanol in bottoms (b) (1) 0.65

(2) 1.86 (3) 0.846

(c) 8 + reboiler theoretical stages 14.5 actual plates + reboiler (d) 21 plates + reboiler

7.33 (a) approx. 18 theoretical stages (b) approx. 18 theoretical stages (c) approx. 8

7.55 (a) 208o_F

0.75 mole fraction H in vapor and 0.35 mole fraction H in liquid (b) 10,000 Btu/lbmol

0.77 mole fraction H in vapor and 0.38 mole fraction H in liquid (c) 54 mol% is vapor