A process for separating components or a fluid mixture using membranes comprising a selective layer made from copolymers of an amorphous per fluorinated dioxolane and a fluorovinyl monomer. The resulting membranes have superior selectivity performance for certain fluid components of interest while maintaining fast permeance compared to membranes prepared using conventional perfluoropolymers, such as Teflon® AF, Hyflon® AD, and Cytop®.

This invention discloses a membrane composition, a method of making, and applications for a new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes. Gas permeation tests on these membranes demonstrated that they not only showed high selectivities, but also showed extremely high CO.sub.2 plasticization resistance under CO.sub.2 pressure up to 4923 kPa (700 psig). This new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes can be used for a wide range of gas separations such as separations of H.sub.2/CH.sub.4, He/CH.sub.4, CO.sub.2/CH.sub.4, CO.sub.2/N.sub.2, olefin/paraffin separations (e.g. propylene/propane separation), O.sub.2/N.sub.2, iso/normal paraffins, polar molecules such as H.sub.2O, H.sub.2S, and NH.sub.3 mixtures with CH.sub.4, N.sub.2, H.sub.2, and other light gases separations. The membranes can also be used for liquid separations such as in the removal of organic compounds from water.

The present disclosure relates to a cross-linked thermally rearranged polymer membrane and a method for preparing the same. The cross-linked thermally rearranged polymer membrane prepared according to the present disclosure has fluorine atoms distributed in a cross-linked thermally rearranged polymer membrane so as to have a concentration gradient from the surface and is formed into a three-layer structure consisting of a fluorine deposition layer, a transition layer and a thermally rearranged polymer base layer, thereby having remarkably increased selectivity as compared to the existing commercialized gas separation membrane and, particularly, enabling helium to be separated with high purity and recovery rate from a natural gas well, etc. even with a small membrane area, and thus being commercializable.

Disclosed is a mass selective fluid bandpass filter. This filter provides for selecting gas molecules of a specific mass from a gas sample containing molecules of two or more mass species. This provides for a low power, low cost apparatus for producing .sup.3He from terrestrial sources of helium gas by selective enrichment. This invention further discloses a portable, field deployable means of .sup.3He/.sup.4He ratio determination employing one or more of the effects consisting of: statistical linear regression plots of heat ramps, variable emission currents within a quadruple mass spectrometer, use of a quadrupole mass spectrometer in concert with ultrahigh vacuum maintained by non-evaporable getter pumps, and/or construction of vacuum housing structures from non-steel or non-stainless steel alloys, and or non metallic materials selected from a group consisting of: aluminum, titanium, ceramics, or glass. This provides a compact, sensitive field deployable unit with low power consumption.

A process for separating components or a fluid mixture using membranes comprising a selective layer made from copolymers of an amorphous per fluorinated dioxolane and a fluorovinyl monomer. The resulting membranes have superior selectivity performance for certain fluid components of interest while maintaining fast permeance compared to membranes prepared using conventional perfluoropolymers, such as Teflon? AF, Hyflon? AD, and Cytop?.

This invention discloses a membrane composition, a method of making, and applications for a new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes. Gas permeation tests on these membranes demonstrated that they not only showed high selectivities, but also showed extremely high CO.sub.2 plasticization resistance under CO.sub.2 pressure up to 4923 kPa (700 psig). This new type of high selectivity, high plasticization-resistant and solvent-resistant, both chemically and UV cross-linked polyimide membranes can be used for a wide range of gas separations such as separations of H.sub.2/CH.sub.4, He/CH.sub.4, CO.sub.2/CH.sub.4, CO.sub.2/N.sub.2, olefin/paraffin separations (e.g. propylene/propane separation), O.sub.2/N.sub.2, iso/normal paraffins, polar molecules such as H.sub.2O, H.sub.2S, and NH.sub.3 mixtures with CH.sub.4, N.sub.2, H.sub.2, and other light gases separations. The membranes can also be used for liquid separations such as in the removal of organic compounds from water.

A process for separating components of a gas mixture using gas-separation copolymer membranes. These membranes use a selective layer made from copolymers of an amorphous perfluorinated dioxolane and a fluorovinyl monomer. The resulting membranes have superior selectivity performance for gas pairs of interest while maintaining fast gas permeance compared to membranes prepared using conventional perfluoropolymers, such as Teflon AF, Hyflon AD, and Cytop.

A process for separating components of a gas mixture using gas-separation copolymer membranes. These membranes use a selective layer made from copolymers of an amorphous perfluorinated dioxolane and a fluorovinyl monomer. The resulting membranes have superior selectivity performance for gas pairs of interest while maintaining fast gas permeance compared to membranes prepared using conventional perfluoropolymers such as Teflon AF, Hlyflon AD, and Cytop.

The present invention relates a process and apparatus that recovers a helium rich stream from a mixed gas having low concentrations of helium therein. More specifically, the invention relates to an integrated process and apparatus for treating a mixed feed gas from an operating process that produces a fluid product from natural gas containing helium, such as processes that produce ammonia, methanol, or liquid hydrocarbons.

The invention relates to the technical field of membrane separation, and discloses a hollow fiber membrane and preparation method and use thereof. The hollow fiber membrane includes a support, a selective layer, and a transition layer between the support and the selective layer, wherein at least a portion of the transition layer is embedded in the support. The hollow fiber membrane has a high selectivity and good mechanical properties.