Exam 3

Question 1

Adjacent keys

Answer 1

Adjacent components in the list of components written in order of increasing volatility

Question 2

Characteristics to pick membrane

Answer 2

Cheap , way to clean, low pressure drop, strong, selective for desired permeate component

Question 3

Why separation membranes used in composite form where membrane is used attached to a backing material?

Answer 3

Membrane materials usually have small pores giving large pressure drop for flow. To lower it , we have to keep it to in as possible. But this makes membrane mechanically weak so needs support

Question 4

Structure of hollow fibre membrane

Answer 4

Looks like shell and tube heat exchanger with a bundle of hollow membranes in a cylinder

Question 5

Advantages and disadvantages of hollow membranes

Answer 5

+: low pumping power, high packing density, high concentrations in the retenate
-: fragile fibres, poor handing of solids, hard to clean