# D downcomer froth height is operation acceptable or

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: At the top of the column, the reflux rate is 1.3(0.947)(768) = 945 lbmol/h. The overhead vapor rate = 1.3[0.947(768) + 768] = 1,944 lbmol/h. Use the entrainment flooding correlation of Fig. 6.24, with densities from a simulation program, where the abscissa is, FLV LM L V = VM G L 1/ 2 = 945(30.9) 0.0703 1,944(30.9) 47.2 1/ 2 = 0.0192 (1) From Fig. 6.24, for 24-inch tray spacing, CF = 0.38 ft/s. Because FLV < 1, Ad /A = 0.1. FHA = 1.0, FF = 1.0, and since = 20 dynes/cm, FST = 1.0. From Eq. (6-24), C = FSTFFFHACF = (1)(1)(1)(0.38) = 0.38 ft/s From Eq. (6-40), U f = C L - V / V 1/ 2 = 0.38 47.2 - 0.0703 / 0.0703 1/ 2 = 9.84 ft / s From a rearrangement of Eq. (6-44), solving for the fraction of flooding, 4VMV 4(1,944 / 3,600)(30.9) f = 2 = 2 = 0.95 or 95% Unacceptable! D U f 1 - Ad / A V 6 (9.84)(314)(1 - 01)(0.0703) . . At the bottom of the column, the boilup rate from Exercise 7.41 is 1.3(1.138)(1,209) = 1,789 lbmol/h. The liquid rate leaving the bottom tray = 1.3(1,376 + 1,201.9) = 3,351 lbmol/h....
View Full Document

## This note was uploaded on 09/08/2008 for the course CHE 244 taught by Professor Selebi during the Spring '06 term at Lehigh University .

Ask a homework question - tutors are online