Separation Process Principles- 2n - Seader & Henley - Solutions Manual

Required a sketch of the membrane device analysis a

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

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: equired: A sketch of the membrane device. Analysis: A sweep fluid is generally required. In some cases, a vacuum could be pulled on the permeate side. The membrane device is shown below. Exercise 1.10 Wanted: The differences, if any, between adsorption and gas-solid chromatography. Analysis: Adsorption can be conducted by many techniques including fixed bed, moving bed, slurry, and chromatography. In chromatography, unlike the other adsorption techniques, an eluant is used to carry the mixture through the tube containing the sorbent. Multiple pure products are obtained because of differences in the extent and rate of adsorption, resulting in different residence times in the tube. The tube is made long enough that the residences do not overlap. Exercise 1.11 Wanted: Is it essential in gas-liquid chromatography that the gas flows through the packed tube in plug flow? Analysis: Plug flow is not essential, but it can provide sharper fronts and, therefore, the chromatographic columns can be shorter. Exercise 1.12 Wanted: The reason why most small particles have a negative charge. Analysis: Small particles can pick up a negative charge from collisions in glass ware. In an aqueous solution, inorganic and polar organic particles develop a charge that depends on the pH of the solution. The charge will be negative at high pH values. Exercise 1.13 Wanted: Can a turbulent-flow field be used in field-flow fractionation? Analysis: Field-flow fractionation requires a residence-time distribution of the molecules flowing down the tube. This is provided best by laminar flow. The residencetime distribution with turbulent flow is not nearly as favorable. Turbulent flow would not be practical. Exercise 1.14 Subject: Sequence of three distillation columns in Fig. 1.9 for separating light hydrocarbons. Given: Feed to column C3 is stream 5 in Table 1.5. Alter the separation to produce a distillate containing 95 mol% iC4 at a recovery of 96%. Find: (a) Component flow rates in the distillate and bottoms from column C3. (b) Percent purity of nC4 in the bottoms. (c) Percent recovery of iC4, for 95 mol% iC4 in the distillate, that will maximize the percent purity of nC4 in the bottoms. Assumptions: Because of the relatively sharp separation in column C3 between iC4 and nC4, assume that all propane in the feed appears in the distillate and all C5s appear in the bottoms. Analysis: (a) Isobutane to the distillate = (0.96)(171.1) = 164.3 lbmol/h Total distillate rate = 164.3/0.95 = 172.9 lbmol/h Normal butane to the distillate = 172.9 - 2.2 - 164.3 = 6.4 Material balance around column C3, in lbmol/h: Component Feed Distillate Propane Isobutane Normal butane Isopentane Normal pentane Total 2.2 171.1 226.6 28.1 17.5 445.5 2.2 164.3 6.4 0.0 0.0 172.9 Bottoms 0.0 6.8 220.2 28.1 17.5 272.6 (b) % Purity of nC4 in bottoms = (220.2/272.6) x 100% = 80.8% (c) Let x = lbmol/h of nC4 in the distillate y = lbmol/h of iC4 in the distillate P = mole fraction purity of nC4 in the bottoms 226.6 − x 226.6...
View Full Document

This document was uploaded on 02/24/2014 for the course CBE 2124 at NYU Poly.

Ask a homework question - tutors are online