Chapter 8, Problem 8.34P

An adiabatic membrane separation unit is used to dry (remove water vapor from) a gas mixture containing 10.0 mole% H₂O(v), 10.0 mole% CO. and the balance CO₂. The gas enters the unit at 30°C and flows past a semipermeable membrane. Water vapor permeates through the membrane into an air stream. The dried gas leaves the separator at 30°C containing 2.0 mole% H₂O(v) and the balance CO and CO₂. Air enters the separator at 50°C with an absolute humidity of 0.002 kg H₂O/kg dry air and leaves at 48°C. Negligible quantities of CO, CO₂, O₂, and N₂ permeate through the membrane. All gas streams arc at approximately 1 atm.

1. Draw and label a flowchart of the process and carry out a degree-of-freedom analysis to verily that you can determine all unknown quantities on the chart.

Calculate (i) the ratio of entering air to entering gas (kg humid air/mol gas) and (ii) the relative humidity of the exiting air.

List several desirable properties of the membrane. (Think about more titan just what it allows and does not allow to permeate.)