Abstract: The invention relates to a method for achieving low oxygen levels in a natural gas stream without the use of a catalytic system. In one embodiment, the method comprises: membrane treatment for the removal of the bulk of CO2 and oxygen in the natural gas feed and the addition of a PSA system using a carbon molecular sieve adsorbent for the adsorption of residual oxygen.

Abstract: The invention relates to a method for utilizing low-quality tail gas derived from a pressure swing adsorption system or membrane system, which is used to upgrade biogas, as a beneficial fuel for the facility and/or digester boiler.

Abstract: The invention relates to a method for achieving low oxygen levels in a natural gas stream without the use of a catalytic system. In one embodiment, the method comprises: membrane treatment for the removal of the bulk of CO2 and oxygen in the natural gas feed and the addition of a PSA system using a carbon molecular sieve adsorbent for the adsorption of residual oxygen.

Abstract: The present invention is directed to an improved integrated process for the removal of heavy hydrocarbons, carbon dioxide, hydrogen sulfide, and water from a raw natural gas feed stream. More specifically, the integrated process of the present invention comprises a three step process involving the adsorption of heavy hydrocarbons and water on an adsorbent bed selective for the same, a subsequent aqueous lean amine treatment for the absorptive removal of acid gases, such as carbon dioxide and hydrogen sulfide, and an adsorptive removal of water. The process of the present invention results in a highly purified natural gas product stream.

Abstract: The present invention is directed to an improved integrated process for the removal of heavy hydrocarbons, carbon dioxide, hydrogen sulfide, and water from a raw natural gas feed stream. More specifically, the integrated process of the present invention comprises a three step process involving the adsorption of heavy hydrocarbons and water on an adsorbent bed selective for the same, a subsequent aqueous lean amine treatment for the absorptive removal of acid gases, such as carbon dioxide and hydrogen sulfide, and an adsorptive removal of water. The process of the present invention results in a highly purified dry natural gas product stream.

Abstract: A pressure swing adsorption process for the separation of impurities such as nitrogen and carbon dioxide and recovery of hydrocarbons from a natural gas stream utilizes two separate adsorption systems, the first containing an adsorbent selective for nitrogen, carbon dioxide or both and the second containing a hydrocarbon-selective adsorbent. In the process, the natural gas stream is passed through a first adsorbent to form a product stream enriched with methane and to adsorb nitrogen and/or carbon dioxide and which further co-adsorbs at least a portion of the hydrocarbons contained in the feed stream. The hydrocarbons are recovered by passing a low pressure waste stream from the first pressure swing adsorption stage which contains co-adsorbed nitrogen and/or carbon dioxide and hydrocarbons and directing the waste stream to the second pressure swing adsorption stage to adsorb the hydrocarbons and produce a product stream enriched in nitrogen and/or carbon dioxide.

Abstract: An improved pressure swing adsorption process is provided for removing or separating a gas from a mixture of gases. The PSA process comprises selectively adsorbing a gas from the mixture to form a product gas having a reduced concentration of the selectively adsorbed gas and a low pressure purge stream containing a higher level of the selectively adsorbed gas than contained in the mixture. During regeneration of the adsorbent a co-current recycle stream is provided which has a pressure less than the product stream, but greater than the purge stream for recycle to feed so as to minimize loss of the product gas to purge. The PSA process is particularly useful for removing carbon dioxide from coal bed methane.

Abstract: Disclosed is a novel pressure swing adsorption (PSA) pre-purification process for a feed gas prior to its introduction into a cryogenic distillation unit. The PSA process uses in a multi-bed adsorbent system the steps, performed in a cyclical manner, of feed, blowdown, purge and repressurization. Optionally, a pressure equalization step is employed in the process. The resulting process provides for continual repressurization during the cycle and a constant flow rate of purified feed gas to the distillation unit.

Abstract: A process is disclosed for the catalytic dehydrogenation of C.sub.3 -C.sub.4 hydrocarbons wherein an integrated scheme comprising a cold box unit and a pressure swing adsorption unit is employed to reject methane produced in the dehydrogenation reaction from the hydrogen-rich recycle stream. The process results in a significant improvement in the efficiency of the separation of the reaction by-products and a corresponding increase in the overall feed capacity of the process.

Abstract: A process for the separation and recovery of the product stream resulting from the dehydrogenation of dehydrogentable hydrocarbons which process utilizes an integrated system for the recovery of liquid olefin product by use of a compression system, a pressure swing adsorption unit and a chiller system to concentrate the olefin poroduct.

Abstract: A process for recovering hydrogen-rich gases and increasing the recovery of liquid hydrocarbon products from a hydrocarbon conversion zone effluent is improved by a particular arrangement of a refrigeration zone, a pressure swing adsorption (PSA) zone, and up to two separation zones. The admixing of at least a portion of the tail gas from the PSA zone with a hydrogen-rich gas stream recovered from a first vapor-liquid separation zone results in significantly improved hydrocarbon recoveries and the production of a high purity hydrogen product. The process is especially beneficial in the integration of the catalytic reforming process with vapor hydrogen consuming processes such as catalytic hydrocracking in a petroleum refinery.

Abstract: A process is provided for the concentration and recovery of ethylene and heavier components from a hydrocarbon feedstream. A pressure swing adsorption (PSA) process is used to remove from hydrocarbon feedstream light cut comprising hydrogen, carbon monoxide, and methane and subsequently concentrate a heavy cut comprising the ethylene and heavy components in the PSA tail gas. In one aspect of the invention, an FCC off gas is separated into a light cut and a heavy cut and the heavy cut is routed to an ethylene plant. In another aspect of the invention, a C.sub.2 -rich stream is withdrawn from an ethylene plant and used to enhance the recovery of the ethylene and heavier stream in the PSA process and an ethylene-rich stream is returned to the ethylene plant.

Abstract: A process for the separation and recovery of the product stream resulting from the dehydrogenation of dehydrogenatable hydrocarbons which process utilizes a chiller system for the recovery of olefin product liquid and a pressure swing adsorption unit to concentrate the olefin product liquid which is not recovered by the chiller.

Abstract: A process for the separation and recovery of the products stream resulting from the dehydrogenation of dehydrogenatable hydrocarbons which process utilizes an integrated system for the recovery of liquid olefin product by the use of a compression system, a pressure swing adsorption unit and a chiller system to concentrate the olefin product.

Abstract: Adsorption processes are provided for the separation of a feedstream containing less readily, intermediately, and more readily adsorbable components using first and second adsorption zones. The second adsorption zone utilizes a cycle that includes a cocurrent displacement step and the intermediately adsorbable components are recovered therefrom by countercurrent depressurization. The first adsorption zone is purged with a stream from the second adsorption zone to recover the more readily adsorbable components. The processes are particularly suitable for recovering carbon monoxide from feedstreams containing hydrogen, carbon monoxide and other compounds such as methanol and higher alcohols, methane, dimethyl ether, dimethyl ketone, water, carbon dioxide, oxygen and mixtures thereof.

Abstract: A process and an apparatus are disclosed for controlling the concentration of a component in an effluent stream from a permeable membrane gas separation system. A gaseous feed stream is passed to the membrane system at a substantially constant flow and elevated pressure. Control is achieved by sensing a characteristic of an effluent stream that is indicative of the concentration of the component, i.e., permeate or non-permeate stream, and performing a pressure adjustment on the permeate stream or non-permeate stream, to vary the concentration of the component in the effluent stream as necessary to obtain a predetermined concentration of the component in the effluent stream. A product stream having a relatively constant pressure and purity can be obtained by sensing a characteristic of a desired effluent stream, e.g., permeate, and performing a pressure adjustment on the other effluent stream, e.g., non-permeate.

Abstract: A pressure swing adsorption process is provided for the separation of a feedstream containing less readily, intermediately readily, and more readily adsorbable components using first and second adsorption zones. The second adsorption zone utilizes a cycle that includes a cocurrent displacement step and the intermediately adsorbable components are recovered therefrom by countercurrent depressurization. The first adsorption zone is purged with a stream from the second adsorption zone to recover the more readily adsorbable component. In one aspect of the invention, there is provided a methanol reforming process wherein hydrogen and carbon monoxide product streams are recovered from a methanol reactor effluent stream also containing components selected from methanol, methane, dimethyl ether, carbon dioxide, oxygen and water.

Abstract: Processes are disclosed for the separation of light hydrocarbons from a feedstream containing hydrogen, light hydrocarbons and heavy hydrocarbons. The processes employ thermal swing adsorption zone to adsorb heavy hydrocarbons and a pressure swing adsorption zone to remove the remaining light hydrocarbons. At least a portion of the product from the pressure swing adsorption zone is used to purge the thermal swing adsorption zone. Specific applications of the process of the present invention are disclosed with relation to hydrodealkylation processes and dehydrocyclodimerization processes.

Abstract: A gas separation process and system for integrating a gas permeable membrane system with a multiple bed pressure swing adsorption system to produce a mixed gas product having a preset adjustably controlled gas ratio and a high purity second gas component. The permeate stream from the gas permeable membrane system is fed to the PSA unit and the tail gas from the PSA unit is compressed and blended with the non-permeate stream to form the mixed gas product. The pressure of the permeate stream is controlled to adjustably control the gas ratio of the mixed gas product.