Abstract: Disclosed is a method for removing hydrogen sulfide from natural gas. The method includes passing a natural gas feed including methane and hydrogen sulfide (H2S) through a membrane at normal operating conditions. The membrane is an asymmetric hollow fiber membrane or an asymmetric film composite membrane including a porous layer and a nonporous skin layer. The asymmetric hollow fiber membrane or the nonporous skin layer of the asymmetric film composite membrane plasticizes during the method by exposure to condensable gases with high critical temperature under the operating conditions. The membrane preferentially removes H2S over methane from the natural gas feed at a H2S/methane selectivity of from 7 to 40 when measured at 35° C. and 45 bar.

Abstract: The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

Abstract: The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

Abstract: A gas separation device comprising a porous support structure comprising polymeric hollow fibers, and an inorganic mesoporous membrane disposed on the porous support structure is disclosed. The inorganic mesoporous membrane is uniform and free of defects. Further, the inorganic mesoporous membrane comprises a network of interconnected three-dimensional pores that interconnect with the porous support structure. The gas permeances of the inorganic mesoporous membrane is substantially higher than the gas permeances of the polymeric hollow fibers. A method of fabricating the gas separation device is also disclosed.

Abstract: Methods of making thin, defect-free, mesoporous silica coatings on polymeric hollow fibers are provided, along with membranes, devices and applications employing same.

Abstract: Compositions and processes are disclosed for economical separation of fluid mixtures. Broadly, the present invention discloses ionic polymer compositions that are useful for perm-selective membrane separations. More particularly, ionic polymers of the invention comprise a plurality of repeating structural units having as a constituent part thereof organic ionic moieties consisting of nitrogen containing anions and/or cations. In the form of non-porous membranes, ionic polymers of the invention facilitate recovery of purified organic and inorganic products from fluid mixtures by means of perm-selective membrane separations. The present invention also provides methods for forming the ionic polymers, for example by treating selected nitrogen-containing organic polymers with acids, or treating a polymeric material comprising a plurality of carboxylate groups with an amine.

Abstract: A composition of and a method of making high performance hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer comprising covalently bonded ester crosslinks. The resultant hollow fiber membrane exhibits a high permeability of CO2 in combination with a high CO2/CH4 selectivity. Another embodiment provides a method of making the hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.

Abstract: A polymeric composite may be used for forming fluid separation membranes. The membranes may be formed from polyimide, polyamide or poly (pyrrolone-imide) materials. Polyamides may be formed by the condensation of a tetraamine, a tetraacid, and a diamine. Polyimides and poly (pyrrolone-imides) may be formed by the cyclization of a polymer precursor. A polymeric composite may include a dithiolene or a mixture of dithiolenes. A polymer matrix incorporating dithiolenes may exhibit an olefin/paraffin solubility selectivity. A solubility selectivity may be between about 1.1 and about 2.0.