Abstract: High purity methane and carbon dioxide are recovered from landfill gas in an integrated multi-column adsorption system having a temperature swing adsorption section (TSA) for pretreatment of the crude landfill gas to remove trace impurities therefrom, the thus cleaned gas being fed to a pressure swing adsorption section (PSA) for bulk separation of CO.sub.2 from methane. Regeneration of the impurity-laden adsorbent bed of the TSA section is carried out using part of the CO.sub.2 product gas recovered from the PSA section which gas is heated to thermal regeneration temperature.

Abstract: An oxygen-rich gas product of at least about 95% O.sub.2 purity is obtained from ambient air in a single-stage pressure swing adsorption operation carried out in four steps, comprised of: (a) selective adsorption of nitrogen from the air feed at superatmospheric pressure, (b) followed, without intermediate purge or rinse, by pressure let down through countercurrent gas withdrawal to about atmospheric level, (c) desorption by evacuation of the adsorbent bed to subatmospheric pressure level of 1/20 (5%) or less than 1/20.sup.th of the pressure prevailing during the adsorption step; and (d) repressuring the evacuated bed with part of the oxygen-rich effluent obtained during the adsorption step. Optionally, the operating cycle may include pressure equalization between two columns performed intermediate steps (a) and (b), whereby O.sub.2 recovery is increased. Under the prescribed conditions the oxygen production capacity at high purity level (.about.95%) is substantially increased.

Abstract: Adjusted gas compositions having two or more components in desired proportions for particular industrial uses are obtained from available feed gas mixtures accompanied by recovery of one or more valuable individual gases of high purity, by a novel selective adsorption-desorption scheme carried out in a multi-column PSA system. Following initial adsorption of one or more components from the feed gas mixture at high pressure the sorbate-laden column is subjected to a high pressure rinse using as rinse gas the previously recovered more strongly adsorbed species. After the rinsing step, the column is depressured to a selected level and purged with part of the unsorbed gas effluent discharged during the initial adsorption step until a preset amount of the earlier sorbed gas is recovered in the purge effluent as the readjusted binary gas mixture of desired proportions.

Abstract: A mild oxidizing acid wash of activated carbon in the presence of an oxidation catalyst produces an adsorbent, with a large carboxyl IR spectra peak, having a favorable water adsorption isotherm that can be used for both pressure swing adsorption, PSA, or thermal swing adsorption, TSA, drying of gases. The oxidation catalyst is a metal salt wherein the metal is selected from the group consisting of copper, chromium and nickel.

Abstract: The gaseous effluent from oxidation of organic material with oxygen-rich gas, which effluent contains CO.sub.2 (and possible CO) and unreacted residual oxygen, is compressed and charged to a PSA system for selective removal of the CO.sub.x, the thus purified oxygen-rich product from the PSA system being recycled to the oxidation reaction. In the PSA system comprised of a plurality of adsorption columns operated in parallel, each column in turn undergoes the steps of: (1) selective adsorption of CO.sub.2 from the feed gas; (2) depressuring to near ambient level; (3) purging with air to remove sorbed CO.sub.2 ; and (4) repressuring with part of the recycled effluent from step (1).

Abstract: A pressure swing adsorption process is provided for the direct production from ambient air of a moderately enriched oxygen product gas. The production of a product gas having an oxygen concentration of 23 to 30% is effected by a three step cycle wherein (1) the feed air is charged to a bed of nitrogen selective adsorbent until the bed is brought from atmospheric pressure to a pressure in the range of up to 10 atmospheres, (2) reducing the bed pressure to an intermediate level by withdrawal of oxygen enriched product gas therefrom and (3) finally venting the bed to restore atmospheric pressure. By an alternative mode including a fourth step of purging the bed following the venting step, a product of 23 to 45% oxygen concentration is obtained.

Abstract: The present invention involves an improved adsorbent for gas separation processes. The adsorbent comprises a binary ion exchanged Type X zeolite wherein between 5% and 40% of the available ion sites are occupied by Ca, and between 60% and 95% of the available ion sites are occupied by Sr. The present adsorbent is especially useful for the adsorption of N.sub.2 from an air stream at superambient pressure to produce an O.sub.2 -rich product stream.

Abstract: To improve the column dynamics of commercial pelleted sodium aluminosilicate zeolite adsorbents used in gas separation, the pellets are treated by washing in dilute aqueous mineral acid. The treatment is most effective as applied to sodium mordenite pellets, employing hydrochloric acid of about 0.1 normality.

Abstract: A simplified low-cost system designed for home use in the direct administration of high purity oxygen to a patient, utilizes a single adsorption column containing successive layers of adsorbent. The first layer is composed of a molecular sieve adsorbent for removal of water and CO.sub.2 from the air feed stream. The second layer is a molecular sieve adsorbent which preferentially retains nitrogen. The sequence and conditions of the several steps of the operating cycle are designed to recover a therapeutic gas stream of about 90% oxygen content.

Abstract: Argon is recovered from a gas stream comprising the same in admixture with oxygen and nitrogen, by a vacuum swing adsorption (VSA) process wherein the mixed gas is passed through an adsorbent bed having thermodynamic selectivity for adsorption of nitrogen and the unadsorbed portion then passed through a second adsorbent bed having kinetic selectivity for retaining oxygen. Both adsorbent beds are regenerated by vacuum desorption, applied to the first bed for a longer time period than that of the second bed. Further purification of the recovered argon may be carried out, if desired, by catalytic hydrogenation of residual oxygen therein. The mixed gas stream fed to the VSA unit may be that obtained from the crude argon column associated with a cryogenic air separation plant and the waste gas from the VSA unit may be recycled to the main column of the cryogenic air separation plant, thus enhancing argon recovery.

Abstract: A process is set forth for the removal of carbon dioxide from air in an adsorption bed wherein the regeneration energy is reduced by the use of a heat recuperator and a purge sequence which avoids the removal of heat from the adsorption bed during regeneration.

Abstract: A system and method of controlling a vacuum swing adsorption process. During an adsorption step, the percent composition of the gas being processed is sensed as it is introduced into at least one train of beds which comprises a pretreatment bed and an air fractionation bed. The control system terminates the adsorption step when a predetermined high level oxygen composition is detected. During a rinse step the percent composition of the high purity nitrogen in the train is sensed. The control system terminates the rinse step when a predetermined low level oxygen composition is detected. During an evacuation step, the level of pressure in the train is sensed and predetermined subatmospheric pressure levels are detected for terminating evacuation in first, the air fractionation bed, and second, the pretreatment bed.

Abstract: A pressurized, non-refillable recreation ball inflated with a mixture of sulfur hexafluoride and air for improved shelf life and pressure retention is obtained by filling the ball with sulfur hexafluoride in a range of 65% to 75% by volume and 35% to 25% by volume of air. Preferably, the sulfur hexafluoride is present in an amount of 71% by volume. The recreation balls include tennis balls, racquet balls, squash balls, handballs and other non-refillable pressurized balls.

Abstract: PdCl.sub.2 /C catalyst which has been deactivated in the oxidation of an olefinic halide or olefinic hydrocarbon present as contaminant in air or other inert oxygen-containing gas stream, is regenerated by prolonged exposure to air or other oxygen-containing gas stream at temperatures below 70.degree. C. and preferably below 60.degree. C.

Abstract: Improved oxygen recovery in the operation of a pressure swing adsorption system for air fractionation is obtained by passng the air, freed of water and CO.sub.2, through an adsorbent bed maintained at elevated temperature throughout the cycle and which is selective for retention of nitrogen, and consequent withdrawal of an oxygen-rich primary effluent product. In a preferred embodiment ambient air is passed through a pretreater section providing an adsorbent bed for removal of water and carbon dioxide. The thus purified air is compressed with consequent rise in temperature and then only partly cooled down by exchange with cooler desorbed and purged nitrogen-rich gas products withdrawn from the main adsorbent beds. These nitrogen-rich products thus heated by the exchange are employed in regenerating a water and carbon dioxide laden bed of the pretreater section. While the adsorption-desorption is operated in a pressure swing cycle, the pretreater section is operated in an independent thermal swing cycle.

Abstract: The water content of high purity nitrogen obtained by vacuum swing adsorptive fractionation of ambient air, is removed in a companion thermal swing drying system operated in association with the air fractionation system but at independent cycle time period, wherein water-laden nitrogen from the air fractionation system is passed through a desiccant bed of solid water-retaining adsorbent in said drying system while withdrawing dry nitrogen of high purity therefrom, and the adsorbed water is subsequently removed from said desiccant adsorbent by regeneration thereof with heated dry air effluent obtained in rinsing the air fractionating column with desorbed process nitrogen.

Abstract: Moisture and CO.sub.2 are removed from atmospheric air by adsorption of these respectively in separate beds. The moisture laden bed is regenerated by pressure swing adsorption in a relatively short operating cycle while the CO.sub.2 -laden bed is regenerated thermally at considerably longer time intervals. The described method is of particular advantage in connection with the pretreatment of air prior to cryogenic distillation for separation of oxygen and nitrogen therein.

Abstract: Multicomponent gas mixtures containing (1) hydrogen as primary component, (2) a secondary key component that is more strongly sorbed by the adsorbent than hydrogen and (3) one or more dilute components more strongly sorbed than both hydrogen and the secondary key component, are subjected to selective adsorption in a pressure swing cyclic adsorption system for the separate recovery of high purity hydrogen and of the secondary component. A given example is the treatment of effluent gas from a hydrodesulfurization plant after removal of the sulfur, wherein hydrogen and methane are separately recovered substantially freed of C.sub.2 + hydrocarbons present in such effluent gas.

Abstract: Multicomponent gas mixtures containing: (1) hydrogen as primary component, (2) a secondary key component that is more strongly sorbed by the adsorbent than hydrogen, and (3) a minor quantity of one or more dilute components less strongly sorbed than the secondary key component, are subject to selective adsorption in an adiabatic pressure swing cyclic system for the separate recovery of high purity hydrogen and of the secondary component. A given example is the treatment of a shift converter effluent gas from a hydrocarbon reformer plant, wherein hydrogen and carbon dioxide are separately recovered as key components substantially freed of minor dilute components such as methane, carbon monoxide and nitrogen.

Abstract: Multicomponent gas mixtures containing: (1) hydrogen as primary component, (2) a secondary key component that is more strongly sorbed by the adsorbent than hydrogen, and (3) a minor quantity of one or more dilute components less strongly sorbed than the secondary key component, are subject to selective adsorption in an adiabatic pressure swing cyclic system for the separate recovery of high purity hydrogen and of the secondary component. A given example is the treatment of a shift converter effluent gas from a hydrocarbon reformer plant, wherein hydrogen and carbon dioxide are separately recovered as key components substantially freed of minor dilute components such as methane, carbon monoxide and nitrogen.