Membranes used to recover low concentrations of organic solvents from air have extremely high membrane selectivities and are from 100 to 10,000 times more permeable to organic solvents than air. Because these selectivities are so high and because of the limitations of availale vacuum pumps, it is not possible to operate these membranes at pressure that fully utilize their selectivities. As a result, membrane performance is determined by both selectivity and pressure. It can be shown that with membranes of equivalent solvent permeability there is an optimum membrane selectivity where the cost of recovering a fixed volume of solvent are at a minimum. With membrane systems using liquid ring vacuum pumps able to economically draw a vacuum of 0. 07 atm, the optimum membrane selectivity is in the range of 100 to 200.
|Original language||English (US)|
|Title of host publication||AIChE Symposium Series|
|Number of pages||8|
|State||Published - Dec 1 1986|
ASJC Scopus subject areas
- Chemical Engineering(all)