Abstract: A method for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane, comprising the steps of: compressing a gas stream containing a diluent gas and fluorochemicals to an elevated pressure; heating the gas stream containing a diluent gas and fluorochemicals to an elevated temperature sufficient to increase the flux of the permeate stream and to increase the selectivity of the membrane for the permeation of the diluent gas relative to the permeation of the fluorochemicals; contacting the gas stream with a membrane which is selectively more permeable to the diluent gas than the fluorochemicals to result in a permeate stream rich in the diluent gas and a retentate rich in fluorochemicals; contacting the gas stream with one or more additional membranes which are selectively more permeable to the diluent gas than the fluorochemicals to result in a second permeate stream rich in the diluent gas and a second retentate

Abstract: An installation for detecting the presence of helium in a fluid circuit, the installation including a tapping member constituting a volume comprising a first internal space and a second internal space separated from each other by a semi-permeable partition through which helium can pass, the first space of said tapping member being inserted in series in the fluid circuit, the second space being connected both to a gas source via an orifice having an adjustable aperture, and also to a pumping member via a pipe, the flow pumped through the pipe conveying the flow under viscous conditions towards a feed member connected to a helium leak detector.

Abstract: Novel polyimide gas separation membranes and the process of using such membranes to separate gases are disclosed. The polyimides are formed from rigid aromatic dianhydrides and aromatic diamines that contain sulfonic acid, salified sulfonic acid, or sulfonic ester groups. Methods of preparing improved composite gas separation membranes from the sulfonated polyimides of this invention are disclosed.

Abstract: The process for introducing a filling gas into an enclosure initially containing a holding gas includes a step of introducing the filling gas into the enclosure as well as a step of extracting a specific gas initially contained in the filling gas or the holding gas from a mixture collected at the outlet of the enclosure, and possibly a step of recycling this extracted specific gas. Before the step of introducing the filling gas, the enclosure is purged using a purging gas which differs from the fill and holding gases.

Abstract: The disclosed hybrid membrane and pressure swing adsorption process can recover helium from source streams of about 0.5 to 5 percent by volume helium and concentrate the helium to a concentration of greater than about 98 percent by volume. The process comprises a membrane separation followed by two stages of pressure swing adsorption which are used in series. The source gas will primarily contain hydrocarbons but will contain some nitrogen. The membrane unit will contain a semipermeable membrane which is permeably selective for helium and will to the extent feasible reject hydrocarbons. The permeate gas will be increased in helium content by 2 to 10 times. Part of the residue gas is used in the regeneration of the adsorbent beds in the first stage of pressure swing adsorption. Each stage of pressure swing adsorption will contain a plurality of adsorbent beds, and will be cycled through multiple phases.

Abstract: The invention relates to a process for the separation of a gaseous hydride or a mixture of gaseous hydrides from a gaseous medium containing at least one gas from the group consisting of H.sub.2, Ar, He, according to which the gaseous medium is passed on to a membrane module so that the concentration of the hydride or of the mixture of hydrides obtained at the outlet of the module is higher than their initial concentration in the gaseous medium.

Abstract: The present invention relates to composite membranes and membranes which are formed from modified poly(phenylene oxide) polymers having improved film forming properties and separation characteristics. The present invention further relates to poly(phenylene oxide) polymer and modified poly(phenylene oxide) polymer, having improved membrane forming characteristics and processes for producing the same.

Abstract: A process and system for pressurizing a vessel for integrity testing with gas comprising helium, recovering the gas comprising helium, and purifying the gas comprising helium for reuse. The process for purifying the gas stream comprising helium comprises drying the gas stream; separating the dried gas stream in a membrane separator stage into a helium-enriched permeate product stream and a helium-depleted raffinate stream; recovering helium in the raffinate stream in a membrane stripper stage thereby producing a purge stream; and purging water from the dryer with the purge stream.

Abstract: This invention provides a composite gas separation membrane comprising: (a) a porous polyacrylonitrile structural support material having a polyacrylonitrile surface; (b) a gutter layer coating comprising a crosslinked polar phenyl-containing-organopolysiloxane material on the polyacrylonitrile surface of the structural support material, leaving an uncoated gutter layer surface; and (c) an ultrathin 6FDA type polyimide selective membrane layer coating on the uncoated gutter layer surface. In preferred embodiments, the phenyl-containing-organopolysiloxane material additionally comprises a silica-sol. Processes for making the composite gas separation membrane and for using the membrane to carry out gas separations are also provided.