Abstract: A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is operated in series with a pressure swing adsorption (PSA) system and the PSA reject gas is used as a sweep gas to improve membrane performance. The integrated membrane-PSA system is particularly useful for recovering high-purity hydrogen from a mixture of hydrogen and hydrocarbons, and is well-suited for integration with a steam-methane reformer.

Abstract: Recovery of hydrogen from hydrogen-containing gas mixtures by pressure swing adsorption is increased by utilizing an adsorbent membrane to concentrate hydrogen in the pressure swing adsorption reject gas and recycling the resulting hydrogen-enriched stream to the feed of the pressure swing adsorption system. Lower compression requirements are realized compared with the use of polymeric membranes for the same service because the hydrogen-enriched stream is recovered from the adsorbent membrane as nonpermeate at essentially the membrane feed pressure. Simultaneous permeation of carbon dioxide and methane occur in the adsorbent membrane, which can be operated at feed pressures as low as 5 psig when hydrogen is used as a sweep gas.

Abstract: Improved composite semipermeable membranes including microporous carbonaceous adsorptive material supported by a porous substrate for use in separating multicomponent gas mixtures in which certain components in the mixture adsorb within the pores of the adsorptive material and diffuse by surface flow through the membrane to yield a permeate stream enriched in these components. Methods for making the improved composite membranes are described including one or more oxidation steps which increase the membrane permeability and selectivity.

Abstract: A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is operated in series with a pressure swing adsorption (PSA) system and the PSA reject gas is used as a sweep gas to improve membrane performance. The integrated membrane-PSA system is particularly useful for recovering high-purity hydrogen from a mixture of hydrogen and hydrocarbons, and is well-suited for integration with a steam-methane reformer.

Abstract: A method is disclosed for separating a multicomponent gas mixture comprising at least three components into three product streams by use of adsorbent membrane zones operating in series. Each product is enriched in a different component based upon the relative strength of adsorption of each component on the adsorbent material. A non-permeate primary component product is obtained by the selective adsorption and permeation through the adsorbent membranes of secondary components which are more strongly adsorbed than the primary components in the gas mixture. Two or more permeate streams enriched in the more strongly adsorbed components are withdrawn from the membrane zones as individual secondary products, each of which contains a different component distribution determined by the relative strength of adsorption of the secondary components on the adsorbent material.

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.

Abstract: A new thermal swing adsorption process for the separation of a bulk liquid mixture into its respective components wherein a novel rinse step is employed to achieve high product recovery with a low energy of separation. The invention is particularly useful for separating liquid mixtures containing azeotropes or close-boiling components which are difficult to separate using conventional techniques such as distillation or routine termal swing adsorption. A given example is the separation and recovery of methyl acetate from a bulk liquid mixture containing methyl acetate and water.

Abstract: Composite semipermeable membranes comprising porous adsorptive material supported by a porous substrate are disclosed for use in a process for the separation of multicomponent gas mixtures. In the process, one or more primary components adsorb within the pores of the adsorptive material and diffuse by surface flow through the membrane to yield a permeate stream enriched in one or more of the primary components. Methods for making the composite membranes are described.

Abstract: A method is described for recovering nitrogen from air in a three bed vacuum swing adsorption technique in which the beds are not rinsed with nitrogen gas before recovering a nitrogen recycle stream and a nitrogen product.

Abstract: A rapid adiabatic pressure swing adsorption process with a total cycle time ranging from 6 to 60 seconds with feed being introduced into a single separation vessel having dual adsorption layers operated alternately by a pressurized continuous feed gas involving a continuous feed and two continuous product streams, one being enriched in the less strongly adsorbed component of the feed mixture.

Abstract: A process for preparing an alkyl-tert-alkyl ether wherein an olefin having a double bond on a tertiary carbon atom and a primary alcohol are reacted in the presence of a catalyst under conditions sufficient to produce an azeotropic alcohol/ether/hydrocarbon mixture containing the alkyl-tert-alkyl ether. The azeotropic alcohol/ether/hydrocarbon mixture is subjected to a cyclic liquid phase adsorption process sequence to selectively remove the alcohol. The resulting non-azeotropic ether/hydrocarbon stream can then be easily separated by distillation to provide the desired alkyl-tert-alkyl ether product and a hydrocarbon product. The cyclic adsorption process employed to separate the alcohol from the ether/hydrocarbon mixture comprises introducing the alcohol/ether/hydrocarbon mixture into a plurality of adsorption colums containing an alcohol selective adsorbent, wherein each respective absorption column undergoes successive steps of adsorption and desorption.

Abstract: A process for preparing motor fuel grade alcohol wherein an ethanol fermentation reactor effluent is distilled to produce an overhead product comprising 10 to about 40 mole percent ethanol and a bottom product comprising the non-alcoholic components. The motor fuel grade alcohol is recovered in high yield from the ethanol/water overhead product mixture in a liquid phase cyclic selective adsorption process which comprises a plurality of adsorption columns operated in cycle in a predetermined time sequence, each adsorption column containing an adsorbent, wherein each respective adsorption column undergoes successive steps of adsorption, desorption and rinsing.

Abstract: The present invention is a concentration swing adsorption process for separating a liquid phase feedstock comprising a more adsorbable component (A) and a less adsorbable component (B) with respect to an adsorbent. The process is operated in a system comprising a single or a plurality of adsorption columns containing the adsorbent which are operated in cycle in a predetermined sequence. The following operational steps are performed in the order recited in each of the adsorption columns in its turn. Feedstock is passed through the adsorbent and the more adsorbable component (A) is selectively adsorbed while a stream enriched in component (B) is discharged from the adsorption column. The adsorbent is rinsed in a direction co-current to the feedstock with the more adsorbable component (A) whereby the less adsorbable component (B) is displaced from the adsorbent and a stream comprising a mixture of the more adsorbable component (A) and the less adsorbable component (B) is withdrawn from the adsorption column.

Abstract: A method is disclosed for the thermal regeneration of an adsorbent which contains adsorbed components which can react with and damage the adsorbent at regeneration temperatures. The method comprises passing a hot regeneration gas through a bed of the adsorbent at a sufficiently high flow rate such that the residence time and reaction of the desorbed components in the adsorbent bed are minimized. For removing water from CaX or SrX zeolites, the flow of nitrogen regeneration gas is controlled so that the nitrogen gas residence time in the bed is less than one second.

Abstract: The present invention is directed to a process for removing minor amounts of oxygen from inert gas streams to result in very low levels of oxygen contamination in such inert gas streams, wherein the oxygen is removed by the action of stoichiometric quantities of methanol, which react with the oxygen over a catalyst at ambient feed temperature conditions without a requirement for external heating of the reaction.

Abstract: The present invention is directed to a process for producing endothermic gases from methanol and inert gas streams containing minor amounts of oxygen, wherein the oxygen is reacted with stoichiometric excess quantities of methanol over a catalyst as ambient feed temperature conditions without a requirement for external heating of the reaction to produce an endothermic gas containing very low levels of oxygen and methanol and significant quantities of hydrogen, carbon monoxide, water and carbon dioxide.

Abstract: Multi-column pressure swing adsorption process for simultaneous production of ammonia synthesis gas and carbon dioxide from a reformer off gas having hydrogen, nitrogen and carbon dioxide as major components accompanied by minor quantities of methane, carbon monoxide and argon as impurities. The PSA system features two groups of adsorbent columns in which CO.sub.2 is adsorbed in adsorbers of the first group, the essentially CO.sub.2 -freed effluent being charged to an adsorber of the second group for removal of minor impurities while discharging an effluent gas having an H.sub.2 /N.sub.2 content stoichiometric for NH.sub.3 synthesis. The CO.sub.2 recovered from the first group of adsorbers is available at a high purity for reaction with the ammonia product for production of urea.

Abstract: An ammonia synthesis gas mixture comprised of substantially pure hydrogen and nitrogen in approximately 3/1 molar ratio is obtained form two stage reforming of a methane-rich hydrocarbon charge such as natural gas. About 40% of the fresh natural gas is charged to primary steam reforming and the obtained primary reformate product, containing about 17 volume percent of unreacted methane, is mixed with the other 60% of the fresh natural gas and the mixture is subjected to oxidative reforming with enriched air containing 30 to 35 of O.sub.2, said enriched air being supplied in an amount to produce a secondary reformate containing principally hydrogen and nitrogen, accompanied by a minor amount of oxides of carbon (CO and CO.sub.2). The secondary reformate subjected to shift reaction with steam results in conversion of contained CO to CO.sub.2, thereby releasing hydrogen in an amount which together with the hydrogen previously present in said reformate obtains a H.sub.2 /N.sub.2 molar ratio of about 3/1.

Abstract: Multicomponent gas mixtures containing (1) hydrogen as a 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 subjected to selective adsorption in an integrated adiabatic pressure swing adsorption (PSA) system having three groups of adsorbent columns interconnected for controlled series gas flow from a selected column of one group to a selected column of another group. In the disclosed example, directed to treatment of a shift converter effluent from a hydrocarbon reforming plant, contained carbon dioxide is selectively adsorbed in and recovered from a column of the first group. The minor dilute components (such as CH.sub.4 and/or CO) are retained by adsorption in a column of the second group, thus permitting recovery therefrom of unsorbed high purity hydrogen.

Abstract: In the recovery of methane and carbon dioxide from landfill gas (LFG) a selective adsorption system is employed having a pretreat section operated in temperature swing adsorption mode (TSA) to remove water and trace hydrocarbon contaminants, in flow communication with a pressure swing adsorption section (PSA) for separation of the methane from CO.sub.2 contained in the purified gas stream discharged from the pretreat section. The LFG is introduced into a column in the TSA section and passed consecutively through a layer of activated carbon followed by a layer of solid desiccant such as a molecular sieve zeolite. The activated carbon layer adsorbs trace contaminants such as hydrocarbons and halohydrocabons boiling above methane; the zeolite layer adsorbs water. Regeneration of the adsorbent layers is carried out by flowing hot regeneration gas first through the zeolite layer then into and through the carbon layer.