446results about "Membrane purification/separation" patented technology

An onboard fuel separation apparatus separates a material fuel (gasoline) into a high-octane fuel having a higher octane value than the material fuel and a low-octane fuel having a lower octane value than the material fuel using a separation membrane which selectively allows high-octane value components (such as aromatic components) permeate through the membrane. The apparatus increases the ratio of the amount of the high-octane value components permeating through the membrane to the amount of the high-octane value components contained in the material fuel by, (A) Controlling the temperature of the material fuel supplied to the membrane (B) Increasing partial pressure of the low-octane value components on the high-octane fuel side of the membrane and removing volatiles from the permeate, and (C) Bypassing volatiles in the material feed around the membrane.

A process for treating mixtures of organic components, including azeotropic mixtures. The process includes a gas- or liquid-phase membrane separation step in conjunction with a dephlegmation step to treat at least a portion of the permeate vapor from the pervaporation step. The process yields a membrane residue stream, a stream enriched in the more volatile component as the overhead stream from the dephlegmator and a condensate stream enriched in the less volatile component as a bottoms stream from the dephlegmator. Any of these may be the principal product of the process.

The present invention pertains to a process for the separation of aromatics from a feed stream, including aromatics and non-aromatics by selectively permeating the aromatics through a membrane comprising feeding a mixed phase vapor-liquid feed to a membrane wherein said liquid phase preferentially wets the surface of the membrane.

A sieving membrane comprises a thin, microporous barrier to provide a high flux. The membrane structure can tolerate defects yet still obtain commercially-attractive separations.

A process for the separation of olefinic hydrocarbons from a liquid feedstock composition comprising at least one olefinic hydrocarbon and at least one paraffinic hydrocarbon, said process comprising contacting the liquid feedstock with a supported ionic liquid membrane wherein the supported ionic liquid membrane comprises a membrane impregnated with an ionic liquid composition.

The device described in the present invention can trap plugging particles contained in the liquid feed supplying a reactor functioning in gas and liquid co-current down-flow mode using a specific distributor tray comprising a filtration medium.

The present device is of particular application to the selective hydrogenation of feeds containing acetylenic and dienic compounds.

The present invention provides modified molecular sieve membranes with improved CO₂/CH₄ separation selectivity and methods for making such membranes. The molecular sieve membranes are modified by adsorption of a modifying agent, such as ammonia, within and/or on the membrane.

A membrane process for the removal of sulfur species from a naphtha feed, in particular, a FCC light cat naphtha, without a substantial loss of olefin yield is disclosed. The process involves contacting a naphtha feed stream with a membrane having sufficient flux and selectivity to separate a sulfur deficient retentate fraction from a sulfur enriched permeate fraction, preferably, under pervaporation conditions. Sulfur deficient retentate fractions are useful directly into the gasoline pool. Sulfur-enriched permeate fractions are rich in sulfur containing aromatic and nonaromatic hydrocarbons and are further treated with conventional sulfur removal technologies, e.g. hydrotreating, to reduce sulfur content. The process of the invention provides high quality naphtha products having a reduced sulfur content and a high content of olefin compounds.

The invention relates to an improved membrane pervaporation and vapor permeation system in which the vacuum is produced by a fluid passing through a Venturi-type nozzle. The fluid is chosen from solvents that have little or no affinity for the permeate molecules. It is applicable over process feed rates, and can be used for the separation of aromatic species from hydrocarbon.

A non-woven low surface energy filter element designed to have improved removal of a dispersed liquid phase from a continuous liquid phase is disclosed.

A system and a process for recovering high concentrations of methane from crude natural gas and solid waste landfill exhaust gas uses a sequential combination of a pressure swing adsorber unit operation to remove volatile organic compounds from the crude feed gas mixture followed by a membrane separation unit operation. The membrane separation uses a membrane which is selectively gas permeable to reject transmission of methane and thus to produce a permeate depleted in methane relative to the feed mixture. The permeate is also free of volatile organic compounds and is recycled to the pressure swing adsorber unit operation to regenerate saturated adsorbers.

The present invention discloses a new type of polyimide membrane with high permeances and high selectivities for gas separations and particularly for CO₂/CH₄ and H₂/CH₄ separations. The polyimide membranes have CO₂ permeability of 50 Barrers or higher and single-gas selectivity for CO₂/CH₄ of 15 or higher at 50° C. under 791 kPa for CO₂/CH₄ separation. The polyimide membranes have UV cross-linkable functional groups and can be used for the preparation of UV cross-linked polyimide membranes having CO₂ permeability of 20 Barrers or higher and single-gas selectivity for CO₂/CH₄ of 35 or higher at 50° C. under 791 kPa for CO₂/CH₄ separation.

Disclosed herein is a process for producing a selected butene, comprising obtaining a C4 feed stream comprising C4 paraffins and C4 olefins, splitting the C4 feed stream to form a first stream comprising a first butene and a second stream comprising a second butene, isomerizing at least a part of the second stream to convert a portion of the second butene to the first butene, and recycling at least some of the isomerized part of the second steam to the splitting step, wherein a portion of at least one of the C4 feed stream and the second stream is passed through a facilitated transport membrane to remove butanes, forming at least one purge stream comprising butanes. A process for the conversion of C4 olefins, comprising obtaining a C4 feed stream comprising C4 paraffins and C4 olefins, including 1-butene and 2-butene, and reacting the C4 feed stream in a metathesis reactor to form a second stream is also disclosed. The second stream is fractionated to form one or more product streams and a recycle stream primarily containing C4 olefins and C4 paraffins. The recycle stream and/or the C4 feed stream is passed through a facilitated transport membrane to remove butanes, forming at least one purge stream.

A membrane is used in combination with fractionation and hydrodesulfurization to reduce the sulfur content of hydrocarbon feeds, preferably sulfur-containing naphtha feeds. A membrane separation zone is employed to treat a fraction of effluent from a fractionation zone containing sulfur-containing non-aromatic hydrocarbons to produce a sulfur rich permeate and sulfur deficient retentate. The sulfur rich permeate and a second fraction of the fractionation zone, which contains sulfur-containing aromatic hydrocarbons, are further treated in a hydrodesulfurization zone. The stream from the hydrodesulfurization zone and the sulfur deficient retentate from the membrane separation zone are then processed as low sulfur hydrocarbon streams, especially those streams being processed in the manufacture of gasoline when the initial hydrocarbon stream is naphtha from a fluidized catalytic cracking unit.

A process for separating a homogeneous metathesis catalyst and, optionally, one or more homogeneous metathesis catalyst degradation products from a metathesis reaction mixture containing in addition to said metathesis catalyst and said metathesis catalyst degradation product(s), one or more olefin metathesis products, one or more unconverted reactant olefins, and optionally, a solvent. The process involves contacting the metathesis reaction mixture with a nanofiltration membrane, such as a polyimide nanofiltration membrane, so as to recover a permeate containing a substantial portion of the olefin reaction products, the unconverted reactant olefins, and optional solvent, and a retentate containing the metathesis catalyst, and optionally, metathesis catalyst degradation product(s). In another aspect, this invention pertains to a continuous metathesis reaction-catalyst separation process, preferably, conducted in a nanofiltration membrane reactor.

Isobutene is prepared by dissociating tert-butanol into isobutene and water over an acid ion-exchange resin arranged as a fixed bed in at least one reactor at a temperature of from 80 to 150° C. and at a pressure of from 5 to 25 bar to obtain a reaction mixture, separating the reaction mixture into isobutene, a by-product, water and at least one mixture of undissociated tert-butanol and water. The reactor is operated pseudo-isothermally, with a temperature difference between inflowing and outflowing streams of less than 15 K.

The present invention provides a hydrogen production method capable of producing hydrogen with good efficiency while solving problems such as separation, lower-temperature reaction and heat supply in production of hydrogen by dehydrogenation reaction of raw material oil. Within a reaction tube of a double-tube structure comprising an inner tube composed of a hydrogen separating membrane, a metallic outer tube having a plurality of internal fins, and a metal oxide layer and further a catalyst supported on the fins, hydrocarbon having cyclohexane ring is dehydrogenated to produce hydrogen and aromatic hydrocarbon, and selective membrane separating operation of hydrogen is performed within the reaction system while conducting the dehydrogenation to remove mainly the hydrogen on a permeating side and obtain mainly the aromatic hydrocarbon on a non-permeating side. The other method comprises absorbing at least part of the resulting hydrogen flow to a hydrogen absorbing (storing) alloy to make the pressure on the hydrogen permeating side of the hydrogen separating membrane lower than that on the non-permeating side.

The invention relates to a method for separating reaction products produced during preparation of propylene by dehydrogenating propane. In the method, reaction products produced during preparation of propylene by dehydrogenating propane are separated in a way of combining membrane separation with cryogenic separation. The method comprises the following steps of: (1) cooling pretreated reaction products produced during preparation of propylene by dehydrogenating propane, condensing, feeding into a first-stage flash tank, conveying a gas phase serving as a hydrogen-rich product on the top of the first-stage flash tank outwards, or further cooling, condensing and feeding into a next-stage flash tank, gradually cooling and condensing and performing flash evaporation in sequence, conveying a gas phase serving as a hydrogen-rich product on the top of a last-stage flash tank outwards, conveying a liquid phase at the bottom of each stage of flash tank to an ethane removing tower, and discharging C3 out of a tower kettle of the ethane removing tower; and (2) separating into high-purity hydrogen permeable gas and hydrocarbon-rich impermeable material flow through membrane separation by using a membrane separation unit arranged in the step (1), conveying hydrogen permeable gas outwards, cooling and condensing hydrocarbon-rich impermeable material flow, and conveying to a next-stage flash tank. Compared with the prior art, the method has the advantages of high propylene recovery rate, low energy consumption and simple flow.

A membrane composition comprising an inorganic substrate which has a coating of an associating polymer. The membrane composition includes an inorganic substrate selected from the group consisting of a porous silica hollow tube, an alumina hollow tube and a ceramic monolith.

Process for separating propane and propylene using a distillation column and at least one membrane separation unit constituted by one or more modules operating in series, said membrane separation unit being placed either upstream, or downstream, or upstream and downstream of the distillation column.