Abstract: A gas-liquid contacting tray of the crossflow type with improved means for initiating bubbling activity at the tray inlet region comprising spaced-apart imperforate wall members extending substantially vertically upwardly and transverse to the liquid flow path, contiguously associated and coextensive at their upper edges with an intermediate perforated wall member horizontally extending therebetween.

Abstract: The in-situ cleaning of conduits is enhanced by the passage therethrough of a propelling gas stream having entrained therein cleaning particles of a regular, non-random configuration, and having less than spherical symmetry.

Abstract: Pressure swing adsorption operations for the selective adsorption of a component of a gas mixture is carried out, in multi-bed systems, so that the gas released from a bed during the cocurrent depressurization, provide-purge step is passed partly to another bed and partly to an external vessel. The gas in said vessel is thereafter used to partially repressurize said other bed after it has completed its purge step.

Abstract: In pressure swing adsorption processing including higher pressure adsorption, cocurrent depressurization to intermediate pressure, countercurrent depressurization and/or lower pressure purge and repressurization, a cocurrent purge step is employed at adsorption pressure prior to cocurrent depressurization. Methane or natural gas is advantageously employed as the cocurrent purge gas. The cocurrent purge step reduces the storage of product gas, such as hydrogen, in the bed, enhances product recovery and correspondingly reduces the amount of desired product gas discharged with the waste gas discharged the countercurrent depressurization and/or purge steps used for bed regeneration. The value of the waste gas as a fuel is likewise enhanced by the presence of said methane or natural gas therein.

Abstract: In pressure swing adsorption systems having at least five adsorbent beds, three or more cocurrent depressurization-pressure equalization steps are employed in each processing cycle. At least one indirect equalization step is employed between two direct pressure equalizations in which void space gas released from the product end of a bed is passed directly to another bed initially at lower pressure so as to equalize the pressure therebetween. In such indirect pressure equalization step, said void space gas is introduced into an external storage tank from which it is passed to a bed being repressurized for indirect pressure equalization between two direct equalization steps in the repressurization of said bed. Sequential direct-indirect-direct-indirect or indirect-direct-indirect-direct processing steps are preferred.

Abstract: A portion of the void space gas released from an adsorbent bed during the cocurrent depressurization thereof, and to be used to provide purge gas, is passed directly to a bed to be purged. The remaining portion of such gas is passed simultaneously to an external surge drum. The gas in the external drum is thereafter passed to a bed to be purged.

Abstract: Carbon monoxide - containing gas streams are passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. The active carbon is subsequently reacted with steam or hydrogen to form methane. Surprisingly, hydrogen and water vapor present in the feed gas do not adversely affect CO utilization significantly, and such hydrogen actually results in a significant increase in CO utilization.

Abstract: The hot effluent from the catalytic steam reforming of a major portion of a fluid hydrocarbon feed stream in the reformer tubes of a primary reformer, or said effluent after secondary reforming thereof, is mixed with the hot effluent from the catalytic steam reforming of the remaining portion of the feed discharged from the reformer tubes of a primary reformer-exchanger. The combined gas stream is passed on the shell side of the reformer-exchanger countercurrently to the passage of feed in the reformer tubes thereof, thus supplying the heat for the reforming of the portion of the feed passed through the reformer tubes of the reformer-exchanger. At least about 2/3 of the hydrocarbon feed stream is passed to the reformer tubes of said primary reformer, heated by radiant heat transfer and/or by contact with combustion gases, at a steam/hydrocarbon mole ratio of about 2-4/1.

Abstract: In a pressure swing adsorption system for the purification of hydrogen to be used in an ammonia synthesis gas, nitrogen is employed as a purge gas at an elevated purge pressure. The hydrogen recovered at adsorption pressure contains about 20-25% nitrogen and is advantageous for use as said ammonia synthesis gas. The purge gas is expanded to generate power that can be used to compress air being passed to an air separation system. The nitrogen recovered therein can be employed as said purge gas, while the oxygen recovered can conveniently be employed in a hydrogen generation system used to form said hydrogen passed to the pressure swing adsorption system.

Abstract: A rapid pressure swing adsorption process utilizes two or more adsorbent beds, each of which undergoes on a cyclic basis, high pressure feed-adsorption, countercurrent exhaust and repressurization. The feeding of the feed gas mixture, such as air, to the adsorption system is temporarily discontinued upon completion of the feed step to each bed, with the discontinuity of feed before commencing the passing of said feed gas mixture to the next succeeding bed being essentially the same throughout the processing cycle, with the feed step at adsorption pressure for each bed being essentially the same and with said feed step being shorter in duration than said exhaust step.

Abstract: Carbon monoxide-containing gas streams having a relatively high concentration of hydrogen are pretreated so as to remove the hydrogen in a recoverable form for use in the second step of a cyclic, essentially two-step process for the production of methane. The thus-treated streams are then passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. This active carbon is reacted with said hydrogen removed from the feed gas stream to form methane. The utilization of the CO in the feed gas stream is appreciably increased, enhancing the overall process for the production of relatively pure, low-cost methane from CO-containing waste gas streams.

Abstract: A high pressure as stream having a hydrogen content of up to about 90 mol percent is passed to a separator containing a permeable membrane capable of selectively permeating hydrogen. The separator is used to achieve a bulk separation of the desired hydrogen from impurities contained in the gas stream. The separated hydrogen is recovered at a reduced pressure and is passed to a pressure swing adsorption system adapted for operation at said reduced pressure. The off-gas from the separator is recovered essentially at the higher pressure of the gas stream. A portion of the off-gas is throttled to a lower pressure, with appropriate power recovery, and is passed to the pressure swing adsorption system as a co-feed gas, thereby contributing to the recovery of purified hydrogen product and to a reduction in the operating costs for the desired hydrogen separation and purification. The remaining off-gas is recovered as a relatively high pressure fuel or feed gas for other purposes.

Abstract: Bed utilization and product recovery are enhanced in pressure swing adsorption operations, especially for high pressure applications, by terminating cocurrent depressurization at a relatively high intermediate pressure level. Additional void space gas is released from each main adsorption bed by partial countercurrent depressurization prior to conventional countercurrent blowdown. Such additional gas is passed to a satellite bed adapted for simultaneous release of gas from its discharge end, thereby cocurrently depressurizing said satellite bed from said intermediate pressure level, with the thus-released gas being passed to the discharge end of another satellite bed or beds and/or another main bed or beds for pressure equalization and/or purging purposes. The satellite bed is one of a satellite group of adsorption beds containing a lesser number and smaller beds than in said main bed system, the satellite beds not being operated above said intermediate pressure level.

Abstract: A process for forming a gas mixture containing hydrogen and nitrogen for ammonia synthesis, wherein a feed gas mixture containing hydrogen and adsorbable impurities is separated by selective adsorption of the impurities in each of multiple adsorbent beds and discharge of unadsorbed hydrogen-rich gas.

Abstract: Normal paraffins are separated from a hydrocarbon vapor feedstream having 10 to 25 carbon atoms per molecule in a constant pressure process employing a molecular sieve adsorbent and n-hexane for purging and for dilution of gas oil - containing feedstocks. A portion of the countercurrent, desorption purge effluent is employed as a hexane - containing cocurrent purge stream, thereby significantly reducing the required amount of n-hexane purge recycle material, and the size of the equipment and the energy consumed in the processing of said recycle stream. A portion of said countercurrent purge effluent can also be used to provide a source of n-hexane diluent for the gas oil - containing feedstocks, as can the cocurrent purge effluent, resulting in further reduction in required equipment and energy costs, and increasing adsorption efficiency and adsorbent utilization.

Abstract: Carbon monoxide-containing gas streams are passed over a catalyst to deposit a surface layer of active surface carbon thereon essentially without the formation of inactive coke. The active carbon is thereafter reacted with steam or hydrogen to form methane. Enhanced catalyst stability for long term, cyclic operation is obtained by the incorporation of an alkali or alkaline earth dopant in a silica binding agent added to the catalyst-support additive composition.

Abstract: A gas mixture, having a more readily adsorbable gas component to be recovered and a less readily adsorbable gas component, is introduced to an adsorption zone at low pressure, with the pressure being increased prior to purging the less readily adsorbable gas component from the adsorption zone at high pressure. Upon depressurization, the readily adsorbable gas component is recovered at enhanced purity levels. In multiple adsorption zone operations, each zone is passed through the low pressure adsorption, pressurization, high pressure purging and depressurization cycle, in sequence, with pressure equalization steps advantageously being employed between the zones to be pressurized following adsorption and those being depressurized following purging. The invention can be used to recover nitrogen of enhanced purity from air, and to recover high purity methane from mixtures thereof with nitrogen.

Abstract: A method for forming a porous aluminum surface on an aluminum substrate using a potassium fluoaluminate brazing flux in critical weight ratio of 0.05 to 0.6 with an aluminum powder matrix component.

Abstract: An oriented graphite layer is formed on a metallic substrate by providing a coating of particulate carbon thereon, heating the coated substrate in a non-reactive atmosphere to a temperature of between 800.degree. and 1350.degree. C. for saturational diffusion of carbon into the substrate and cooling to a temperature below about 200.degree. C., thereby providing a precipitated oriented graphite film at the surface of the substrate.The substrate may be formed by covering a copper or copper alloy member with a continuous layer of nickel, cobalt, nickel alloy or cobalt alloy. In another embodiment, the substrate with an attached graphite coating is spirally bonded onto a copper tube for use in the field of condensation heat transfer.

Abstract: Normal paraffins are separated from a gas oil-containing hydrocarbon vapor feed stream having 16 to 25 carbon atoms per molecule in a constant pressure process employing a molecular sieve adsorbent and n-hexane for purging and for dilution of gas oil-containing feedstock. Cocurrent purge effluent is used to provide a source of such n-hexane diluent, thereby reducing the equipment size and energy consumption for processing of the n-hexane purge recycle stream and increasing adsorbent utilization or the efficiency of the adsorption process.