Membrane contactor systems for gas-liquid contact

1. A membrane contactor system for use in separating carbon dioxide from a gaseous stream in a continuous flow process, the system comprising:

a housing defining a gas flow path and comprising a first outlet for the carbon dioxide and a second outlet for a purified gas;

an expanded polytetrafluoroethylene microporous membrane positioned in the housing to allow the gaseous stream to flow across a side of the expanded polytetrafluoroethylene microporous membrane, where the expanded polytetrafluoroethylene microporous membrane comprises a structure of nodes connected by fibrils in which surfaces of the structure of nodes and fibrils define a plurality of interconnecting pores extending through the expanded polytetrafluoroethylene microporous membrane, wherein the plurality of interconnecting pores are configured to allow the carbon dioxide to diffuse therethrough;

an oleophobic enhancement coating disposed on the surfaces of the structure of nodes and fibrils to form a coated membrane and configured to provide oleophobicity to the coated membrane without blocking the plurality of interconnecting pores; and

an amine based sorbent liquid disposed on a side of the expanded polytetrafluoroethylene microporous membrane opposite the gaseous stream, wherein the amine based sorbent liquid is configured to absorb the carbon dioxide from the gaseous stream.

2. The membrane contactor system of claim 1 , wherein the coated membrane has an oleophobic rating of at least 4.

3. The membrane contactor system of claim 1 , wherein the coated membrane has an oleophobic rating of at least 6.

4. The membrane contactor system of claim 1 , wherein the coated membrane has an oleophobic rating of at least 8.

5. The membrane contactor system of claim 1 , wherein the oleophobic coating comprises a polymer comprising fluorinated C1-32 hydrocarbon moieties.

6. The membrane contactor system of claim 5 , wherein the polymer comprises units derived from polymerization of fluoro(C1-16)alkyl acrylates, fluoro(C1-16)alkyl methacrylates, perfluoro(C1-16)alkyl acrylates, perfluoro(C1-16)alkyl methacrylates, fluorinated and perfluorinated C1-12 olefins, fluoro(C1-12)alkyl maleic acid esters, perfluoro(C1-12)alkyl maleic acid esters, fluoro(C1-12)alkyl (C6-12)aryl urethane oligomers, fluoro(C1-12)alkyl allyl urethane oligomers, fluoro(C1-12)alkyl urethane acrylate oligomers, fluoro(C1-12)alkyl urethane acrylate oligomers, or a combination comprising at least one of the foregoing.

7. The membrane contactor system of claim 1 , wherein the amine based sorbent liquid comprises 2-amino-2-methyl-1, 3-propanediol, 2-hydroxyethyl piperazine, methyldiethanolamine, monoethanolamine, tetraethylenepentamine, triethanolamine, polyethylene imine, or a combination comprising at least one of the foregoing.

8. The membrane contactor system of claim 7 , wherein the amine based sorbent liquid further comprises a solvent, wherein the solvent comprises alcohol, cyclic ketone, ester, ether, glycerol, methoxy triethylene, glycol diacetate, polyethylene glycol, propylene carbonate, 1,2-propylene glycol, or a combination comprising at least one of the foregoing.

9. A gas turbine engine comprising:

an exhaust treatment system configured to remove carbon dioxide from a combustion exhaust stream, wherein the system comprises:

a housing defining a gas flow path and comprising a first outlet for the carbon dioxide and a second outlet for a purified exhaust;

an expanded polytetrafluoroethylene microporous membrane positioned in the housing to allow the exhaust stream to flow across a side of the membrane, wherein the membrane comprises a structure of nodes connected by fibrils in which surfaces of the structure of nodes and fibrils define a plurality of interconnecting pores extending through the membrane, wherein the pores are configured to allow the carbon dioxide to diffuse therethrough;

an oleophobic enhancement coating disposed on surfaces of the structure of nodes and fibrils and configured to provide oleophobicity to the membrane without blocking the plurality of interconnecting pores; and

an amine based sorbent liquid disposed on a side of the membrane opposite the exhaust stream, wherein the amine based sorbent liquid is configured to absorb the carbon dioxide from the exhaust stream to form the purified exhaust.

10. The membrane contactor system of claim 1 , further comprising a solvent added to the amine based sorbent liquid, wherein the solvent is configured to enhance the carbon dioxide sorption rate of the amine based sorbent.