The distillation column shown below is used to separate compound A from compound B in an adiabatic fashion. A liquid mixture of A and B is fed at a specified temperature into a distillation column (stream 1). At the top of the column, a vapor stream that is A-rich (stream 2) passes through a condenser that completely condenses the mixture. Half of this liquid leaves the condenser as the overhead product, or distillate, (stream 4), and the other half of the liquid returns to the distillation column as reflux (stream 3). At the bottom of the column, a liquid stream that is B-rich is partially vaporized by a reboiler. The vapor from the reboiler (stream 5) returns to the distillation column as boilup while the liquid from the reboiler (stream 6) leaves the condenser as the bottoms product. The composition, temperature, and enthalpies for each stream component are given in the table below.  

a) Take 100 moles of the feed stream as a basis. What is the net heat supplied in this process? 

 

b) Again, taking 100 moles of the feed stream as the basis, what is the heat removed at the condenser (QC), and the heat inputted at the reboiler (QR)? (Make sure your answer for QC is negative, indicating that heat is removed by the condenser.) 

 

c) Suppose now that instead of the condensed liquid from the top of column being split into two equal streams to form the reflux and the overhead product, it is split into two streams, with the reflux being 3 times the overhead product. As before, take a basis of 100 mol of feed and determine the net heating requirements for the process and the heat removed in the condenser and added in the reboiler.

feed Distillation Column reflux overhead product boilup condenser reboiler bottoms product Stream 1 2 3 4 5 6 State Temperature (C) mol A/mol mol B/mol A Liquid 65.0 Vapor 70.0 Liquid 50.0 50.0 Liquid Vapor 95.0 Liquid 95.0 0.610 0.950 0.950 0.950 0.400 0.140 0.390 0.050 0.050 0.050 0.600 0.860 (kJ/mol) (kJ/mol) 452 431 7233 6513 0 0 0 0 a) Take 100 moles of the feed stream as a basis. What is the net heat supplied in this process? 7542 1375 7196 1301