HW11_with_hints_KS_v5_9dec05

HW11_with_hints_KS_v5_9dec05 - Chemical Engineering 150B-...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Page 1 of 4 Chemical Engineering 150B- Fall 2005 Problem Set #11 Due Friday December 9 th , 2005 200 points Note: There are 7 problems in this assignment (see both pages). Problem 1. (40 Points) A distillation operating will separate a mixture of 8 components with the following feed rates at 700 kPa: Compound f i (kmol /hr) C 3 2500 iC 4 400 nC 4 600 iC 5 100 nC 5 200 nC 6 40 nC 7 50 nC 8 40 It is known that the heavy key is iC 5 , which will have a distillate rate of 15 kmol/hr, and the light key is nC 4 , which will have a bottoms rate of 6 kmol/hr. Furthermore, assume for all parts of this problem that only the light key and heavy key distribute; all other components do not distribute. Determine the following: (a) the minimum number of equilibrium stages and the distribution of nonkey components by the Fenske equation. (b) what class of separation is this? (c) the minimum external reflux rate and distribution of nonkey components at minimum reflux by the appropriate Underwood equation (see class notes from Wed, November 23 for handling distributing keys and non-distributing other components) if the feed is a bubble-point liquid at column pressure. Hint: You may find the following equation useful: 3 12 61 2 ln ln P TT TP a aa Ka a P P =+++ + , where P is in psia, T is in o R, and the constants are the following: Compound a T1 a T2 a T6 a P1 a P3 C 3 -970,688.5626 0 7.15059 -0.76984 6.90224 iC 4 -1,166,846 0 7.72668 -0.92213 0 nC 4 -1,280,557 0 7.94986 -0.96455 0 iC 5 -1,481,583 0 7.58071 -0.93159 0 nC 5 -1,524,891 0 7.33129 -0.89143 0 nC 6 -1,778,901 0 6.96783 -0.84634 0 nC 7 -2,018,803 0 6.52914 -0.79543 0 nC 8 0 -7,646.81641 12.48457 -0.73152 0
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Page 2 of 4 In addition, you might find MathCAD useful to find the bubble-point temperature of the feed, bottoms, and distillate streams, so that you can determine the K-value of each component in each stream. This will allow the calculation of volatility of each stream for various components to help you use the Fenske and Underwood equations.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This homework help was uploaded on 04/02/2008 for the course CHEM 150b taught by Professor Bell during the Spring '08 term at Berkeley.

Page1 / 4

HW11_with_hints_KS_v5_9dec05 - Chemical Engineering 150B-...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online