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US 7,479,227 B2Granted
Liquid-phase separation of low molecular weight organic compounds
AssigneeMembrane Technology and Research, Inc.
InventorsAndre R. Da Costa, Ramin Daniels, Ankur D. Jariwala
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Abstract
A process for separating a component from a low molecular weight organic mixture by pervaporation. The process uses fluorinated membranes and is particularly useful for treating mixtures containing light organic components, such as methane, propylene or n-butane.
Claims42
A pervaporation process for separating a first component from a liquid organic mixture, comprising the steps of:
- a) passing the liquid organic mixture across the feed side of a separation membrane having a feed side and a permeate side, the separation membrane having a selective layer comprising a polymer comprising repeat units of a cyclic structure of an at least 5-member fluorinated ring, the polymer having a fractional free volume less than 0.3, a glass transition temperature of at least about 100° C., and an oxygen permeability below 800 Barrer;
- (b) providing a driving force for transmembrane permeation;
- (c) withdrawing from the permeate side a permeate vapor stream enriched in the first component compared to the liquid organic mixture;
- (d) withdrawing from the feed side a residue liquid stream depleted in the first component compared to the liquid organic mixture.
1 more element
A pervaporation process for separating a first component from a liquid organic mixture, comprising the steps of:
- (a) passing the liquid organic mixture across the feed side of a separation membrane having a feed side and a permeate side, the separation membrane having a selective layer comprising a fluorinated polymer having a fractional free volume less than 0.3, a glass transition temperature of at least about 100° C., a fluorine:carbon atom ratio in the polymer of at least 1:1, and an oxygen permeability below 800 Barrer;
- the separation membrane being further characterized in that it provides a membrane selectivity in favor of propylene over propane of at least about 3 and a propylene pressure-normalized flux of at least about 10 GPU when challenged at 20° C. with a liquid mixture of 50 wt % propylene/50 wt % propane at a feed pressure of 150 psig and a permeate pressure of 0 psig;
- (b) providing a driving force for transmembrane permeation;
- (c) withdrawing from the permeate side a permeate vapor stream enriched in the first component compared to the liquid organic mixture;
- (d) withdrawing from the feed side a residue liquid stream depleted in the first component compared to the liquid organic mixture.
2 more elements
A pervaporation process for separating a liquid organic mixture comprising propylene and propane, comprising the steps of:
- (a) passing the liquid organic mixture across the feed side of a separation membrane having a feed side and a permeate side, the separation membrane having a selective layer comprising a fluorinated polymer having a fractional free volume less than 0.3, a glass transition temperature of at least about 100° C., a fluorine:carbon atom ratio in the polymer of at least 1:1, and an oxygen permeability below 800 Barrer;
- and either:
- (i) wherein the selective layer comprises repeat units of a cyclic structure of an at least 5-member fluorinated ring, or
- (ii) wherein the separation membrane is further characterized in that it provides a membrane selectivity in favor of propylene over propane of at least about 3 and a propylene pressure-normalized flux of at least about 10 GPU when challenged at 20° C. with a liquid mixture of 50 wt % propylene/50 wt % propane at a feed pressure of 150 psig and a permeate pressure of 0 psig;
- (b) providing a driving force for transmembrane permeation;
- (c) withdrawing from the permeate side a permeate vapor stream enriched in propylene compared to the liquid organic mixture;
- (d) withdrawing from the feed side a residue liquid stream depleted in propylene compared to the liquid organic mixture.
4 more elements
Dependencies are inferred from the claim text.