Abstract: Zeolites exchanged with lithium cations and polyvalent cations are prepared by first partially ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with polyvalent cations, then heat-treating the partially polyvalent cation-exchanged zeolite, then ion exchanging the heat-treated zeolite with ammonium cations, and then reacting the ammonium cation-exchanged zeolite with a water-soluble lithium compound under conditions which result in the removal of ammonia from the reaction zone.

Abstract: Zeolites exchanged with lithium, rubidium, cesium cations and trivalent cations are prepared by first partially, fully or excessively ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with trivalent cations, then calcining the partially, fully or excessively trivalent cation-exchanged zeolite, and then ion exchanging the calcined zeolite with lithium rubidium, cesium cations, thereby replacing hydrogen and any sodium and/or potassium cations remaining in the zeolite with lithium, rubidium, cesium cations, whereby trivalent cations present in the zeolite will not be substantially replaced by the lithium ions.

Abstract: The present invention provides for a process for purifying atmospheric air prior to its separation by cryogenic distillation. The process utilizes three adsorbent layers, the first primarily removes water; the second primarily removes CO2; and the third layer is designed to remove displaced gas components such as N2O and hydrocarbons which are displaced by the second layer. It has been found that CaX type adsorbents provide the removal of N2O and hydrocarbons in the third layer.

Abstract: Novel compositions of molecular sieve adsorbents are provided in which at least 50% of the exchangeable cations are selected from those of Li, Ca, Ag and Cu and which have within their pore system metal oxide, metal oxide precursors or mixtures thereof. These compositions are useful for the separation of gases and, in particular, the separation of nitrogen from air to produce oxygen or oxygen-enriched gas.

Abstract: Carbon dioxide is removed from gas streams comprised predominantly of gases that are less strongly adsorbed than is carbon dioxide by passing the gas stream through a bed of type X zeolite having a silicon to aluminum atomic ratio not greater than about 1.15 and at least 75% of the exchangeable cations of which are potassium ions, thereby adsorbing the carbon dioxide from the gas stream. The process is particularly advantageous when applied to the removal of low levels of carbon dioxide from gas streams at temperatures of about 0 to 80° C.

Abstract: A gas separation process comprising feeding a gaseous mixture comprising at least two components having different adsorption characteristics into an adsorption vessel containing at least one adsorbent material capable of preferentially adsorbing at least one of the gaseous components in the gaseous mixture and subjecting the gaseous mixture to non-cryogenic conditions which enable the preferentially adsorbable gaseous component in the gaseous mixture to adsorb onto the adsorbent material and separate from the non-adsorbed component in the gaseous mixture which pass through the adsorbent vessel wherein at least one adsorbent material in the adsorbent vessel comprises a composite particle having an inner core comprising a non-porous, non-adsorbent material and at least one outer layer comprising the adsorbent material. In another embodiment of the process of the present invention a hollow particulate adsorbent material is utilized.

Abstract: Substantially all of the carbon dioxide is removed from a gas containing up to about 1% by volume carbon dioxide by subjecting the gas to a pressure swing adsorption process using a two layer adsorption system, wherein the first layer contains activated alumina and the second layer is a zeolite or a combination of zeolites having a silicon to aluminum atomic ratio of at least 1.5. The process is particularly suitable for removing substantially all carbon dioxide and water vapor contained in air prior to subjecting the air to cryogenic distillation.

Abstract: Ethene is separated from a gas mixture containing ethane by a pressure swing adsorption process carried out at a temperature in the range of about 50 to about 200° C., wherein the adsorption step of the process is conducted by passing the gas mixture through an adsorption zone containing type A zeolite whose exchangeable cations are preferably made up of at least about 60 but not more than 75% sodium ions and more than 25 and up to about 40 percent potassium ions.

Abstract: Adsorbent composites composed of microparticulate zeolites at least 90% of whose particles have a characteristic particle dimension not greater than about 0.6 micron and a macropore inert binder. The composites are useful for separating strongly adsorbed gas components from gas mixtures. Microparticulate type X zeolites composites are particularly useful for separating nitrogen or carbon dioxide from air.

Abstract: Carbon dioxide is separated from gaseous hydrocarbons by a cyclic adsorption process using at a temperature in the range of about -50 to about 200.degree. C., wherein the adsorption step of the process is conducted by passing the gas mixture through an adsorption zone containing carbon molecular sieve or type A zeolite whose exchangeable cations are made up of about 50 to about 90% sodium ions and about 10 to about 50 percent potassium ions.

Abstract: Acetylene is stored at elevated pressure by charging with acetylene at elevated pressure a pressure vessel (typically a gas cylinder) containing carbonaceous adsorbent able reversibly to adsorb acetylene. The adsorbent has: (a) a specific micropore volume equal to or greater than 0.5 cm.sup.3 /g; (b) a specific mesopore volume equal to or greater than 0.5 cm.sup.3 /g; (c) a bulk density equal to or greater than 0.25 g/cm.sup.3 ; and (d) a surface area per volume equal to or greater than 400 m.sup.2 /cm.sup.3. Alternatively or in addition to (a) and (b) above, the specific volume of pores having a diameter in the range of 1.5 to 3.0 nm is equal to or greater than 0.3 cm.sup.3 /g, but the sum of the specific mesopore volume and the specific micropore volume should always be equal to or greater than 1.0 cm.sup.3 /g. Preferably, at least 75% of the specific mesopore volume is contributed by mesopores having a diameter in the range of 2 to 5 nm and at least 90% of the micropores have a diameter of at least 0.4 nm.

Abstract: Gas cylinders are filled with mixtures of gases comprising a minor component, which is to be present in the mixture at a concentration of 10% or less of the total volume of the cylinder, and a major component, which is to be present at a concentration greater than about 10% of the total volume, by charging the lighter component into a chamber of given volume to a pressure and at a temperature such that the volume provides the desired fraction of minor component in the gas mixture, and then flushing the minor component into the cylinder using major component gas as the flushing agent. The pressure at which the minor component volume is to be measured is preferably at or near the final pressure of the filled gas cylinder.

Abstract: Substantially all of the carbon dioxide is removed from a gas containing up to about 1% by volume carbon dioxide by subjecting the gas to a pressure swing adsorption process using as the adsorbent a single layer of zeolite having a silicon to aluminum atomic ratio in the range of 1.5 to 70. The process is particularly suitable for removing substantially all carbon dioxide and water vapor contained in air prior to subjecting the air to cryogenic distillation.

Abstract: Zeolites in particulate form that are uniformly exchanged with both lithium ions and trivalent cations are produced by first partially ion-exchanging the zeolite in powdered form with one or more selected trivalent ions, then agglomerating and calcining the partially trivalent cation-exchanged zeolite, then ion-exchanging the calcined agglomerate with lithium ions, and finally activating the trivalent cation- and lithium ion-exchanged zeolite.

Abstract: Zeolites exchanged with lithium ions and, optionally, with polyvalent cations are prepared by ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with ammonium ions, thereby replacing the sodium and/or potassium ions with ammonium ions, and then reacting the ammonium ion-exchanged zeolite with a water-soluble lithium compound under conditions which result in the removal of ammonia from the reaction zone. Polyvalent ions, which may be present in the zeolite undergoing ion-exchange, will not be substantially replaced by the ammonium or lithium ions.

Abstract: A hydrocarbon stream is cracked to produce a hot gaseous stream which is compressed and cooled to condense almost all of the hydrocarbons contained in the stream. A noncondensed stream remaining after the condensation step, comprised predominantly of hydrogen and C.sub.1 to C.sub.3 hydrocarbons, is subjected to pressure swing adsorption or temperature swing adsorption at an adsorption temperature of about 0.degree. to about 250.degree. C. in a bed of adsorbent which selectively adsorbs ethene and propene, thereby adsorbing substantially all of the ethene and propene from the gas stream. The ethene and/or propene is recovered upon bed regeneration. Higher alkenes are separated from alkanes by various methods.

Abstract: Chabazite, offretite, erionite, levyne, mordenite, gmelinite, zeolite A, zeolite T, EMC-2, ZSM-3, ZSM-18, ZK-5, zeolite L, and beta zeolite whose exchangeable cations are composed of 95 to 50% lithium ions, 4 to 50% of one or more of aluminum, cerium, lanthanum and mixed lanthanides and 0 to 15% of other ions are prepared by ion-exchanging the base zeolite with water-soluble trivalent ion salts and with water soluble lithium salts. The zeolites preferentially adsorb nitrogen from gas mixtures.

Abstract: Carbon dioxide is removed from a gas stream by passing the gas stream through a bed of natural or synthetic clinoptilolite or their chemically-modified derivatives. The process is particularly advantageous when applied to the removal of ppm levels of carbon dioxide from gas streams at temperatures above 20.degree. C.

Abstract: Carbon dioxide is removed from gas streams comprised predominantly of gases that are less polar than carbon dioxide by passing the gas stream through a bed of type X zeolite having a silicon to aluminum atomic ratio not greater than about 1.15, thereby adsorbing the carbon dioxide from the gas stream. The process is particularly advantageous when applied to the removal of low levels of carbon dioxide from gas streams at temperatures above 20.degree. C.

Abstract: Type X zeolites whose charge-compensating cations are composed of 95 to 50% lithium ions, 4 to 50% of one or more of aluminum, cerium, lanthanum and mixed lanthanides and 0 to 15% of other ions. The zeolites preferentially adsorb nitrogen from gas mixtures.