Abstract: A gas-separation membrane assembly, and a gas-separation process using the assembly. The assembly incorporates multiple gas-separation membranes in an array within a single vessel or housing, and is equipped with two permeate ports, enabling permeate gas to be withdrawn from both ends of the membrane module permeate pipes.

Abstract: A process for removing carbon dioxide or nitrogen from gas, especially natural gas. The process uses three membrane separation stages without compression between the second and third stages.

Abstract: A process and equipment for treating natural gas produced by a well that has recently been stimulated, and that contains an undesirably high concentration of the fracturing gas used to stimulate the well. The process involves treating the gas by membrane separation, and provides for control of treatment parameters to compensate for the changing concentration of fracturing gas in the produced gas, as well as changes in gas flow rate.

Abstract: Processes for recovering helium from reject gas streams of various types that arise during natural gas processing. The processes include a membrane gas separation step. The reject gas stream is treated in the membrane separation step to yield a helium-enriched permeate stream and a helium-depleted residue stream. The permeate stream is sent for further helium separation or purification in the gas plant or at another facility or sold as crude helium. The residue stream is discharged from the process to a vent line, fuel line, purge line or the like.

Abstract: A process and apparatus for separating carbon dioxide from gas, especially natural gas, that also contains C3+ hydrocarbons. The invention uses two or three membrane separation steps, optionally in conjunction with cooling/condensation under pressure, to yield a lighter, sweeter product natural gas stream, and/or a carbon dioxide stream of reinjection quality and/or a natural gas liquids (NGL) stream.

Abstract: A process for treating natural gas or other methane-rich gas to remove excess nitrogen. The invention relies on two-stage membrane separation, using methane-selective membranes for the first stage and nitrogen-selective membranes for the second stage. The process enables the nitrogen content of the gas to be substantially reduced, without requiring the membranes to be operated at very low temperatures.

Abstract: An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step uses a rubbery polymeric membrane selective for all C1-C6 hydrocarbons over hydrogen. The process can produce three products: a high-purity hydrogen stream, an LPG stream and a light hydrocarbon fuel gas stream.

Abstract: An improved process and process train for hydrogen separation and production from gas streams containing hydrogen and light hydrocarbons. The process includes both recovery of hydrogen already in the stream by membrane separation and PSA, and production of additional hydrogen by steam reforming of the hydrocarbons.

Abstract: A process for treating natural gas or other methane-rich gas to remove excess nitrogen. The invention relies on membrane separation using methane-selective membranes, but does not require the membranes to be operated at very low temperatures. We have found that, by using a two-step membrane system design, and controlling the operating pressures for the membrane steps within certain ranges, the capital and operating costs of the process can be kept within economically acceptable limits.

Abstract: An improved process and process train for catalytic reforming of hydrocarbons. In its most simple form, the invention includes four unit operations or steps: the reforming itself usually carried out in a series of reactors; one or more steps to separate the reformate liquid product from overhead gases, predominantly C1-C6 hydrocarbons and hydrogen; one or more treatment steps to recover hydrogen from the overhead gases, and one or more treatment steps, including a membrane gas separation step, for the waste gas from the hydrogen recovery step. The process provides improved recovery of hydrogen and LPG, and reduces the amount of gas sent to the fuel line.

Abstract: Processes for providing improved methane removal and hydrogen reuse in reactors, particularly in refineries and petrochemical plants. The improved methane removal is achieved by selective purging, by passing gases in the reactor recycle loop across membranes selective in favor of methane over hydrogen, and capable of exhibiting a methane/hydrogen selectivity of at least about 2.5 under the process conditions.

Abstract: A process for hydroprocessing a fluid stream containing at least hydrogen and hydrocarbons. The process uses a hydrocarbon-selective membrane to reduce the concentration of hydrocarbons and contaminants in the hydrogen stream recycled to the hydroprocessing reactor. The membrane can operate in the presence of hydrogen sulfide. The process also provides the opportunity for increased NGL recovery from the hydrocarbon-enriched membrane permeate stream.

Abstract: Processes and apparatus for providing improved catalytic cracking, specifically improved recovery of olefins, LPG or hydrogen from catalytic crackers. The improvement is achieved by passing part of the wet gas stream across membranes selective in favor of light hydrocarbons over hydrogen.

Abstract: An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.

Abstract: Processes and apparatus for providing improved contaminant removal and hydrogen recovery in hydrogenation reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the hydrogenation reactor recycle loop or purge stream across membranes selective in favor of the contaminant over hydrogen.

Abstract: Processes and apparatus for providing improved contaminant removal and hydrogen reuse in reactors, particularly in refineries and petrochemical plants. The improved contaminant removal is achieved by selective purging, by passing gases in the reactor recycle loop across membranes selective in favor of the contaminant over hydrogen.

Abstract: Processes and apparatus for providing improved catalytic reforming, specifically improved recovery of reformate and hydrogen from catalytic reformers. The improvement is achieved by passing portions of the reactor effluent or streams derived from the reactor effluent across membranes selective in favor of light hydrocarbons over hydrogen.

Abstract: A method for generating electric power, such as at, or close to, natural gas fields. The method includes conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas by means of a membrane separation step. This step creates a leaner, sweeter, drier gas, which is then used as combustion fuel to run a turbine, which is in turn used for power generation.

Abstract: A treatment process for a hydrogen-containing off-gas stream from a refinery, petrochemical plant or the like. The process includes three separation steps: condensation, membrane separation and hydrocarbon fraction separation. The membrane separation step is characterized in that it is carried out under conditions at which the membrane exhibits a selectivity in favor of methane over hydrogen of at least about 2.5.

Abstract: A process for conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas, so that it can be used as combustion fuel to run gas-powered equipment, including compressors, in the gas field or the gas processing plant. Compared with prior art processes, the invention creates lesser quantities of low-pressure gas per unit volume of fuel gas produced. Optionally, the process can also produce an NGL product.