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: 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 process, particularly of the TSA type, for separating impurities of the nitrogen protoxide (N2O) and possibly carbon dioxide (CO2) or ethylene (C2H4) type which are contained in a gas stream, such as air. The impurities of nitrogen protoxide type are removed on a faujasite zeolite having a Si/Al ratio of 1 to 1.5 and containing from 0 to 35% of K+ cations, between 1 and 99% of Na+ cations and between 1 and 99% of Ca2+ cations, preferably at least 50% of Ca2+ cations. The separation is preferably carried out at a temperature of approximately −40° C. to +80° C., preferably at room temperature. Advantageously, the process is employed for prepurifying atmospheric air before cryogenic distillation of the air thus prepurified.

Abstract: Process for separating at least carbon dioxide (CO2) contained in a gas stream, preferably air, in which at least carbon dioxide is adsorbed on a zeolite-X having a Si/Al ratio of approximately 1 to 1.5 and containing at most 35% of K+ cations, between 1 and 99% of Na+ cations and at most 99% of Ca2+ cations. This process is carried out at a temperature ranging from −40° C. to +80° C. Optionally, impurities chosen from water vapour and hydrocarbons, particularly ethylene, are also removed. The air thus purified is then capable of being cryogenically distilled.

Abstract: A method and device for drying a gas by means of adsorption on a desiccant able to be regenerated (11), whereby a portion of the dried gas is used for regenerating the desiccant. The gas portion used for the regeneration is heated in at least two successive steps, said steps being performed in different zones (30,31 or 33-36) situated successively in the flow direction of the gas portion through the regenerating desiccant (11) and by stopping the heating in a zone (30,31 or 33-36) as soon as the desiccant (11) in this zone (30,31 or 33-36) is regenerated, so that this zone (30,31 or 33-36) may already cool down by the gas portion for regeneration while a successive zone (30,31 or 33-36) is still regenerated by the heated gas. In each vessel (7, 8) at least two individually controllable heating elements (25-26; 27-28; 38-41) are present.

Abstract: A method and apparatus for compressing and drying a gas, typically air, are provided in which a multistage compressor is employed to produce interstage and final stage compressed gas. Regenerative adsorbent is employed to dry the final stage compressed gas. Interstage gas is used to regenerate the saturated adsorbent. Preferably, two beds of regenerable adsorbent are provided, each operable in a drying mode and a regeneration mode. In the drying mode, final stage compressed gas is passed through the bed of adsorbent in order to be dried, until the adsorbent is saturated. In the regeneration mode, moisture is removed from the saturated adsorbent by a stream of interstage compressed gas. The two beds are preferably alternately operated in the drying mode and the regeneration mode, in order to provide a continuous process.

Abstract: Device and method for removing volatile compounds from a gas stream, the device including a material which is capable of removing and retaining the volatile compounds while displaying a visible color change, wherein at least some moisture has been removed from the material and there is relative movement between the gas stream and the material.

Abstract: A process is provided for the removal of trace amount of aromatic hydrocarbons from a waste feed gas stream comprising sulfur compounds and the aromatic hydrocarbons. An adsorption process employing an adsorbent such as a high silica zeolite adsorbent having a framework silica to alumina ratio greater than about 15 and having a pore size greater than about 6.2 Angstroms is used to remove from the feed gas mixture aromatic hydrocarbon contaminants and permit the recovery of a high purity sulfur product from the treated effluent stream. The adsorption zone comprises at least 2 adsorption beds wherein one of the first adsorption beds is operating in an adsorption mode and the other is being regenerated at a desorption pressure higher than the adsorption pressure. The regeneration is performed in a closed system or partially closed system, and prior to returning a regenerated adsorption zone to adsorption conditions the waste feed gas stream is used to cool and purge the regenerated zone.

Abstract: Water containing contaminants is removed from a gas or liquid stream and then treated to separate the water from the contaminants. The water is separated using a condenser and a semi-permeable membrane so that it is pure enough to be disposed-of in the local environment by evaporation. The accumulated contaminants may be removed separately for controlled disposal, or reintroduced into the original stream as an alternate method of disposal.

Abstract: Carbon dioxide, water, nitrous oxide and optionally ethylene are removed from a feed air stream by a temperature swing adsorption using a first adsorbent such as alumina to adsorb water, a second adsorbent such as 13X zeolite to adsorb carbon dioxide, and a third adsorbent such as binderless calcium exchanged X zeolite to adsorb nitrous oxide and optionally ethylene, prior to cryogenic separation of the purified air stream.

Abstract: The purge and trap procedure commonly used for analysis of volatile organic compounds in water or air can be significantly improved using traps employing clays and modified clays as adsorbents. Examples of clays include attapulgite clay, attapulgite clay modified with tetrasodiumpyrophosphate, carboxymethylcellulose and the combination thereof, kaolin clay, kaolin clay modified with tetrasodiumpyrophosphate, carboxymethylcellulose or the combination thereof, and mixtures of the above clays.

Abstract: The present invention relates to a thermally regenerable adsorptive process for the purification of a feed air, wherein the feed air is contacted with a solid adsorbent to remove at least water and carbon dioxide, wherein, periodically, the solid adsorbent is thermally regenerated by contacting the solid adsorbent with a regeneration gas stream which is essentially free of at least water and carbon dioxide, wherein the regeneration gas is a nitrogen-enriched stream removed from an elevated pressure air separation unit fed with the purified feed air, characterized in that the removed nitrogen-enriched stream is compressed in a multiple staged compressor and that the regeneration gas is a portion of the nitrogen-enriched stream which is removed from an interstage of the multiple stage compressor and then contacted with the solid adsorbent.

Abstract: A method is provided for separating one or more volatile contaminant components from a gas using a pressure and temperature swing adsorbent filtration filter bed system containing three or more layers of adsorbent materials characterized in that the layers comprise a first layer of adsorbent material, a second layer of dessicant material and a third layer of material capable of adsorbing contaminants that are not retained by the first layer. Preferably the third layer is capable of adsorbing contaminants of relatively low boiling point, e.g. of boiling point less than 50.degree. C., and preferably comprises a microporous adsorbent. The second layer of dessicant material preferably comprises a zeolite.

Abstract: An air prepurification process carried out in a battery of three adsorption vessels arranged in parallel. The process includes three steps: a first step in which non-steady state PSA is carried out in the first and second vessels operated in alternating adsorption and bed regeneration mode while the adsorbent in the third vessel undergoes thermal regeneration; a second step in which non-steady state PSA is carried out in the second and third vessels operated in alternating adsorption and bed regeneration modes while the adsorbent in the first vessel undergoes thermal regeneration; and a third step in which non-steady state PSA is carried out in the first and third vessels operated in alternating adsorption and bed regeneration modes while the adsorbent in the second vessel undergoes thermal regeneration.

Abstract: A process and apparatus for drying and removing carbon dioxide from a hydrogen and carbon monoxide containing synthesis gas by using adsorption vessels containing a first layer of 13 X-zeolite and a second layer of 3 A-zeolite in which the 3 A-zeolite precludes the formation of water of reaction when dry and carbon dioxide-free synthesis gas is used to regenerate the adsorption vessel countercurrent to feed flow of the synthesis gas.

Abstract: In the purification of air to remove water and carbon dioxide and other contaminants prior to cryogenic separation of oxygen and nitrogen, water and carbon dioxide are adsorbed on a solid adsorbent and are periodically desorbed to regenerate the adsorbent by the passing of a heated regenerating gas such that the quantity of heat added to the regenerating gas to produce desorption is no more than 90 percent of the heat of adsorption liberated during the adsorption of the water and carbon dioxide. The process is applicable to removing other contaminants from other gas streams also.

Abstract: Temperature swing adsorption to remove CO.sub.2 from a gas stream is conducted using alumina to adsorb all the water and at least most of the carbon dioxide from the gas stream. Optionally a downstream zone of zeolite may be provided to remove further carbon dioxide and hydrocarbons.

Abstract: An air compressor (1) is cooled by a water circuit (5) which comprises a buffer tank (6) and an air cooled cooler (7) provided with a fan (8) of adjustable speed. The buffer tank is supplied by makeup water and includes a purge (16) which serves, when the ambient temperature is relatively high, to cool the preliminarily separated compressed air from cooling water. Application in processes for separation of air by adsorption or permeation.

Abstract: A method and system for separating one or more components from gas mixtures uses a moving bed of adsorption material particles under continuous and substantially isobaric pressure conditions. Contaminated gases are likewise purified by removing one or more contaminants therefrom using such a moving bed of adsorption material particles under continuous and substantially isobaric pressure conditions.

Abstract: Apparatus for recovering high-boiling point solvents which comprises: a honeycomb-structured rotor 1 having an adsorbent supported thereon; a separator 3 for partitioning the neighborhood of each end face of the rotor into two regions, adsorption zone 5 and desorption zone 4; fan means F.sub.1 that supplies the adsorption zone 5 with air containing a solvent boiling at 150.degree. to 300.degree. C. and which causes part of the clean gas effluent a from the opposite end face of the rotor to be released into the air atmosphere while the remainder is supplied into the desorption zone 4; heating means H for heating the clean gas; cooling means C for separating a solvent enriched gas S into a liquefied product L to be recovered and a cooled lean gas V; and return means F.sub.2 for turning the cooled lean gas V back to the feed gas.

Abstract: The invention relates to a method for the desorption of a sorbent by an air stream which is delivered by a blower and, prior to entering the sorbent, is heated. In order to reduce the desorption time, provision is made for adjusting the mass of the air stream as a function of the outlet temperature of the air stream exiting from the sorbent, in such a way that, when a preset temperature limit value is reached, the mass of the air stream is reduced, and the desorption is continued with an air stream heated to a higher temperature. The method is particularly suitable for the desorption of adsorbent in sorption reactors contained in refrigerant-free air conditioning plants.

Abstract: A system for controlling the atmosphere of a container for use in the storage and/or transportation of perishable goods which includes adsorption apparatus for the selective adsorption in whole or in part and in a predeterminded order of any water vapor, carbon dioxide, oxygen or ethylene contained within the atmosphere, a blower for urging the atmosphere to the adsorption apparatus, and a conduiting for returning the controlled atmosphere to the container.

Abstract: In processes for removing mercury vapor from natural gas streams by selective adsorption in fixed adsorbent beds, water is invariably adsorbed along with the mercury impurity. During the periodic purge regeneration of the adsorbent bed it is desirable to recover as much as possible of the desorbed mercury in the spent regeneration gas in liquid form to avoid reintroducing the mercury into the environment. Cooling this spent regeneration gas under the high pressure conditions involved to condense the mercury can result in the highly undesirable formation of hydrocarbon hydrates if temperatures low enough to condense an adequate amount of mercury are employed. In the process of the present invention, the spent regeneration gas stream, from which some mercury has been removed by cooling, is further treated in a desiccant bed so that it is possible to cool it further in order to condense and remove additional mercury without encountering hydrocarbon hydrate formation.

Abstract: Adsorbers used to dry air frequently contain 4A or 13X molecular sieve zeolites, which are intermittently reactivated by thermal regeneration. When the air pressure in a thermally regenerated adsorber is increased, such as during start-up, after adsorbent reloading, after apparatus repair, maintenance or inspection, or after repressurization following thermal regeneration, nitrogen adsorbs preferentially relative to oxygen in activated 4A and 13X molecular sieve zeolites. This produces an oxygen-enriched, high pressure gas within the adsorber vessel which emerges immediately after the adsorber is brought on line. The oxygen-enriched, high pressure gas can cause fires, explosions, and other deleterious effects in and downstream of such adsorber vessels. This invention provides thermally regenerated air driers and air drying processes using adsorbent compositions that do not adsorb nitrogen preferentially to oxygen.

Abstract: This invention pertains to an improved process for the removal of moisture from a moisture laden gas stream such as air utilizing a membrane dryer unit. The membrane dryer unit is equipped such that it incorporates a selective surface flow adsorbent membrane consisting essentially of an inorganic membrane material selected from the group consisting of alumina and silica gel membranes wherein the membrane has a thickness of approximately 0.5 to 50 microns with a mean pore size of less than about 15 A and preferably within about 4 to 10 A. In the cryogenic separation of air, an air stream contaminated with moisture and carbon dioxide is passed through the membrane dryer unit in countercurrent flow to a dry purge gas, wherein the water is selectively removed from the air stream. The partially dried air stream then is conveyed to an adsorption system operated under thermal swing or pressure swing conditions wherein the residual water and carbon dioxide are removed.