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 30째C and flows past a semi permeable membrane. Water vapor permeates through the membrane into an air stream. The dried gas leaves the separator at 30째C containing 2.0 mole % H2O (v) and the balance CO and CO2. Air enters the separator at 50째C with an absolute humidity of 0.002 kg H2O/kg dry air and Leaves at 48째C. Negligible quantities of CO, CO2, O2, and N2 permeate through the membrane. All gas streams are at approximately 1 atm.
(a) Draw and label a flowchart of the process and carry out a degree-of-freedom analysis to verify that you can determine all unknown quantities on the chart.
(b) Calculate (I) the ratio of entering air to entering gas (kg humid air/mol gas) and (ii) the relative humidity of the exiting air.
(c) List several desirable properties of the membrane. (Think about more than just what it allows and does not allow permeating)