CHE343_F19_HW2_assignment Homework #2 Professor Peter Tessier CHE 343 - Separation Processes,

Homework #2 Professor Peter Tessier CHE 343 - Separation Processes, Fall 2019 Due: Wednesday, September 25 at midnight (11.59PM) Instructions: Show all of your work and make sure all problems are legible and clearly identified. Each problem is worth 10 points. Problem 1. (3.D7) A continuous, steady-state distillation column is fed a mixture that is 70.0 mol% npentane and 30.0 mol% n-hexane. Feed rate is 1000.0 kmol/h. Feed is at 35 oC. Column is at 101.3 kPa. The vapor distillate product is 99.9 mol% n-pentane and the bottoms product is 99.9 mol% nhexane. The system has a partial condenser (thus the distillate product is a saturated vapor) and operates at an external reflux ratio of Lo/D=2.8. The reboiler is a partial reboiler. Find D, B, Qc, and QR. Use data given in problem 3.D6 (included at the end). Use the DePriester chart to determine boiling points. Problem 2. (3.D9) We are distilling 2000.0 kg/h of a saturated vapor feed that is 45.0 wt% ethanol and 55.0 wt% water at a pressure of 1 kg/cm2 . Bottoms product is 0.01 wt% ethanol, and vapor distillate from a partial condenser (see Problem 3.D8 for a description) is 88.0 wt% ethanol. Reflux ratio (in mass flow rates) is Lo/D = 2.9. Reflux is a saturated liquid. A vapor side stream with yside = 0.20 is withdrawn at a rate of 25.0 kg/h. Data are in Figure 2-4 (attached at the end). a. Find D, B, Qc, and QR. b. If the feed ow rate is doubled, find D, B, Qc, and QR. Problem 3. (3.D10) A distillation column is separating 150.0 kmol/h of a saturated liquid mixture that is 30.0 mol% methanol and 70.0 mol% water. The column operates at 1.0 atm pressure. Reflux ratio is 2.0, and reflux is returned as a saturated liquid. We desire a 97.0% recovery of methanol in the distillate and a methanol distillate mole fraction of 0.990. Find distillate ow rate D, bottoms flow rate B, methanol mole fraction in the bottoms xM, bot, and the fractional recovery of water in the bottoms. Problem 4. (3.D13) We are distilling 2000.0 kg/h of saturated liquid feed that is 45.0 wt% ethanol and 55.0 wt% water at a pressure of 1.0 kg/cm2 . Bottoms product contains 0.01 wt% ethanol and vapor distillate (from a partial condenser) is 89.0 wt% ethanol. Reflux ratio (in mass ow rates) is Lo/D= 3.5. Reflux is a saturated liquid. Data is given in figure 2-4 of the textbook (attached at the end). a. Find D, B, Qc, and QR. b. If the feed ow rate is doubled, find D, B, Qc, and QR. Problem 5. (3.G2) Solve Problem 3.D6 (problem statement below) using a process simulator to find Qc and QR. To do this, do a hand calculation to find the value of D. Then arbitrarily set N=40 and Nfeed=20 in the process simulator and do the simulation. This study source was downloaded by from CourseH on :22:35 GMT -05:00 Use the below two problems only as reference. They are not a part of the HW D6.* A distillation column receives a feed that is 40 mol% n-pentane and 60 mol% n-hexane. Feed flow rate is 2500.0 lbmol/h, and feed temperature is 30°C. The column is at 1 atm. A distillate that is 99.9 mol% n-pentane is desired. A total condenser is used. Reflux is a saturated liquid. The external reflux ratio is L0/D = 3. Bottoms from the partial reboiler is 99.8 mol% n-hexane. Find D, B, QR, and Qc. Note: Watch your units on temperature. Where T is in °C and CPV and CPL are cal/ (mol°C) or Btu/ (lbmol°F). Source for λ and CP data is Felder and Rousseau (2004). D8. A partial condenser takes vapor leaving