Abstract: Improved polymer blends, and polymer blend membranes having improved mechanical properties are provided by alteration of the critical solution temperature of the polymer blend spinning solution through the incorporation of organic or inorganic complexing agents.

Abstract: A process for the separation of a gas mixture containing oxygen and nitrogen, including bringing the mixture into contact in an adsorption zone with a first selective adsorbent for nitrogen of faujasite type exchanged to at least 80% with lithium, in which the Si/Al ratio is lower than 1.5 and a second selective adsorbent for nitrogen of zeolite type exchanged with divalent cations such as the alkaline-earth metal or transition metal cations. The second adsorbent is characterized by a nitrogen adsorptivity C.sub.2 lower than the nitrogen adsorptivity C.sub.1 characterizing the first adsorbent, and an adsorption selectivity for nitrogen in relation to oxygen (1.times.10.sup.5 Pa, 20.degree. C.) higher than or equal to 3.

Abstract: In a process for compressing a gas, associated with a unit (5) for separating a gas mixture, the compressor (1, 2, 7) comprises a number of stages less than that which would be necessary to produce an optimal compressor of the isothermal type compressing the same flow rate of the gas to the same pressure. The compressor may compress the gas mixture to be separated or a product of the separation.

Abstract: A device for delivering one of a plurality of gases to an apparatus includes at least two valves. Each valve includes a first conduit permanently connected by one end thereof to an associated sampling line and, by another end thereof, to an associated purge line. Each valve includes a second conduit and an actuator which can be switched between bringing the first conduit into communication with the second conduit and a position for isolating the first conduit from the second conduit. At least the second conduit is free of flow-stagnation volumes. The second conduits of the valves are placed in series in a common gas delivery line for delivering gas to the apparatus. The end of the common gas delivery line opposite the apparatus emerges in an associated purge line. Each purge line passes through an element for creating a pressure drop. A use of the device is as a feed for trace impurities analyzer an atmospheric pressure ionization mass spectrometer or a particles analyzer.

Abstract: A process for the purification of a solution of lithium salts contaminated by metallic cations, comprising (i) passing the solution to be purified through an exchange region packed with a material suitable for the exchange of Li.sup.+ cations by contaminating metallic cations, this material being initially charged more than 95% with Li.sup.+ cations and having a better affinity for the contaminating metallic cations than for Li.sup.+ cations, so as to fix all of the contaminating metallic cations on the material by replacement of Li.sup.+ cations, whereby the solution of lithium salts recovered at the outlet of the exchange zone is stripped of contaminating metallic cations; and (ii) regenerating the material by replacement of the metallic cations fixed on the material with Li.sup.+ cations.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Abstract: The invention provides for gas separation membranes with superior gas transport properties made from certain two- and three-component blends of polyethersulfone with aromatic polyimides, to provide a gas separation membrane with superior productivity and good selectivity.

Abstract: In order to deliver ultrapure helium to a utilization line (1), helium is withdrawn, in liquid or supercritical form, from a storage tank (3), it is filtered in this liquid or supercritical form (at 4), the filtered helium is vaporized and the resulting helium gas is sent to the utilization line (1). The process is applicable to the cooling of integrated-circuit wafers.

Abstract: Process and apparatus for the purification of a cryogenic fluid in liquid, diphase, gaseous or supercritical state, having boiling point Pe, with at least one of its impurities having a boiling point Pe', with Pe'>Pe. The process includes at least one step selected from the group comprised by:a filtration step of at least one impurity in solid state,and an adsorption step of at least one impurity in liquid or gaseous state;and in which there is recovered at least one portion of the cryogenic fluid at least partially purified.

Abstract: Process for the separation of the hydrogen contained in a gas mixture contaminated by carbon monoxide and containing at least one other impurity chosen from the group consisting of carbon dioxide and saturated or unsaturated, linear, branched or cyclic C.sub.1 -C.sub.8 hydrocarbons, comprising bringing the gas mixture to be purified into contact, in an adsorption region, with at least:one first adsorbent selective at least for carbon dioxide and for C.sub.1 -C. hydrocarbons andone second adsorbent which is a zeolite of faujasite type exchanged to at least 80% with lithium, the Si/Al ratio of which is less than 1.5, in order to remove at least carbon monoxide (CO).

Abstract: A plant for separating a gas mixture includes several units having different functions, including a compression unit, a purification unit and a separating unit. Each unit has an attendant cabin which contains monitoring and control systems and, optionally, an analysis system and an electrical distribution system which are necessary for the operation of the respective unit only. The plant may be an apparatus for separating air by cryogenic distillation.

Abstract: A thermally insulated adsorber (1) intended for treating a gas by passing the gas through a bed (15) of an active material, of the type including a cylindrical shell (5) provided with thermal insulation (21) including a wall (25), which is, in particular, parallel to the shell (5) and which, together with the shell, defines a gas-filled cavity (27), the wall (25) and consequently the gas-filled cavity (27) being placed inside the shell (5), between the latter and a bed (15) of an active material arranged inside the shell (5). The gas-filled cavity (27) communicates with a part of the adsorber (1) which includes the gas that is to be treated and/or with a part of the adsorber which includes the gas that has been treated. The adsorber furthermore includes elements (43) for blocking any gas flow through the gas-filled cavity in order to separate the gas that is to be treated from the gas that has been treated. The adsorber may be used to purify the air sent to air distillation plants.

Abstract: The invention relates to a method of inflating a tire comprising the steps of:providing a tire mounted on a rim, said tire comprising a tire valve to allow selective inflation or deflation of said tire, said tire being filled with a certain amount of air;deflating said tire to reach a pressure which is less than or equal to a predetermined low pressure, said predetermined low pressure being lower than atmospheric pressure;inflating said tire with a source of inert gas to reach a pressure at least equal to a pressure greater than atmospheric pressure, to obtain inside said tire a gas mixture comprising between 5% O.sub.2 by volume and 0.5% O2 by volume.It also relates to a tire evacuation apparatus specially adapted thereto.

Abstract: The heat exchanger is of the type comprising a stack of parallel plates and, between these plates, undulant spacers, each pair of plates defining a passage for fluid of generally flat shape. Certain passages (20) are subdivided over one part of their length into two closed subpassages (at 45, 57) at locations longitudinally offset relative to each other. The exchanger is applicable in cryogenic heat exchangers of installations for the distillation of air.

Abstract: A process and plant for air separation by cryogenic distillation. Air is cooled in a main exchanger and is sent to a distillation column in which it separates into an oxygen-enriched liquid and a nitrogen-enriched vapor. A stream of pressurized liquid coming from the apparatus vaporizes in the main exchanger. The refrigeration necessary for the process is generated by expansion of air in one or more turbines immediately downstream of the main exchanger. The turbine or turbines produces or produce, as output, a stream which is at least 95 percent liquid, preferably 100 percent liquid.

Abstract: A process and installation for the separation of air in a cryogenic distillation apparatus (24) comprising a distillation column (30, 42) and in which the supplied air is separated to produce a fraction rich in oxygen and a fraction rich in nitrogen as products. The purities of these products are maintained substantially constant during variations of demand of either product or of the flow rate or of the pressure of the supplied air by introducing an excess of liquid rich in nitrogen into the distillation apparatus when the demand for the product or the flow rate of the supplied air increases, and by withdrawing an excess of liquid rich in nitrogen from the distillation apparatus, and storing this liquid, when the demand for the product or the flow rate of the supplied air decreases.

Abstract: A device for delivering one of a plurality of gases to an apparatus includes at least two valves. Each valve includes a first conduit permanently connected by one end thereof to an associated sampling line and, by another end thereof, to an associated purge line. Each valve includes a second conduit and an actuator which can be switched between bringing the first conduit into communication with the second conduit and a position for isolating the first conduit from the second conduit. At least the second conduit is free of flow-stagnation volumes. The second conduits of the valves are placed in series in a common line for delivering gas to the apparatus. The end of the common line opposite the apparatus emerges in an associated purge line. Each purge line passes through an element for creating a pressure drop. A use of the device is as a feed for an ionization mass spectrometer.

Abstract: The invention relates to a method for improving the separation of water in a tall oil preparation process which comprises: a neutralization step, in which a mixture of tall oil soap and water is neutralized with carbon dioxide; a water separation step, in which the aqueous phase containing bicarbonate is separated from the tall oil soap; and a cooking step, in which the tall oil soap obtained from the previous step is cooked with sulfuric acid in order to form tall oil, the improvement comprising the fact that, after the neutralization with carbon dioxide but before the water separation step, the pH is adjusted with an acidically reacting substance, such as bisulfite. The invention also relates to a method for the preparation of tall oil, the method comprising the steps stated above.

Abstract: Methods and systems of delivering ultra-high purity gas to a point of use are claimed and described. The methods include providing a source of ultra-high purity liquid (the source preferably at a pressure and temperature sufficient to maintain the liquid in substantially the liquid phase); transporting (preferably via pressure in the source alone) the ultra-high purity liquid from the source to one or more means to effect a phase change of the ultra-high purity liquid to an ultra-high purity gas; effecting a phase change (preferably at or near equilibrium vaporization conditions) of the ultra-high purity liquid to form an ultra-high purity gas in the one or more means to effect the phase change; and routing the ultra-high purity gas from the means to effect the phase change to a point of use (preferably with no intermediate, potentially impurity-generating media between the means to effect the phase change and the point of use other than ultra-clean conduit).

Abstract: A process for optimizing the growth of fish reared in a pond, comprising injecting oxygen into the pond in a controlled quantity according to different cycles.