摘要:
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.
摘要:
The present invention discloses microporous UZM-5 zeolite membranes, methods for making the same, and methods of separating gases, vapors, and liquids using the same. The small-pore microporous UZM-5 zeolite membrane is prepared by two different methods, including in-situ crystallization of one or more layers of UZM-5 zeolite crystals on a porous membrane support, and a seeding method by in-situ crystallization of a continuous second layer of UZM-5 zeolite crystals on a seed layer of UZM-5 zeolite crystals supported on a porous membrane support. The membranes in the form of disks, tubes, or hollow fibers have superior thermal and chemical stability, good erosion resistance, high CO2 plasticization resistance, and significantly improved selectivity over polymer membranes for gas, vapor, and liquid separations.
摘要:
The present invention discloses a new type of high performance polymer membranes prepared from aromatic polyimide membranes by thermal treating and crosslinking and methods for making and using these membranes. The polymer membranes were prepared from aromatic polyimide membranes by thermal treating under inert atmosphere followed by crosslinking preferably by using a UV radiation source. The aromatic polyimide membranes were made from aromatic polyimide polymers comprising both pendent hydroxy functional groups ortho to the heterocyclic imide nitrogen and cross-linkable functional groups in the polymer backbone. The membranes showed significantly improved selectivity and permeability for gas separations compared to the aromatic polyimide membranes without any treatment. The membranes can be fabricated into any convenient geometry and are not only suitable for a variety of liquid, gas, and vapor separations, but also can be used for other applications such as for catalysis and fuel cell applications.
摘要:
The present invention involves the use of a novel membrane system for natural gas upgrading. This membrane system includes a first-stage membrane such as a membrane prepared from the polymer of intrinsic microporosity (PIM) to selectively remove hydrocarbons from C3 to C35 to control the dew point of natural gas, and a second-stage membrane such as a polybenzoxazole (PBO) or crosslinked PBO membrane to selectively remove CO2 from natural gas. The new membrane system described in the current invention eliminates the use of high cost and high footprint membrane pretreatment. Therefore, the membrane system can significantly reduce the footprint and cost for natural gas upgrading compared to the current commercially available membrane systems that include a non-membrane-related pretreatment system.
摘要:
The present invention discloses new types of polybenzoxazole-based mixed matrix membranes and methods for making and using these membranes. The polybenzoxazole-based mixed matrix membranes are prepared by fabricating a polyimide-based mixed matrix membrane by dispersing molecular sieve particles in a continuous aromatic polyimide matrix with pendent hydroxyl groups ortho to the heterocyclic imide nitrogen; and then converting the polyimide-based mixed matrix membrane to a polybenzoxazole-based mixed matrix membrane by heating between 200° and 600° C. under inert atmosphere or vacuum. The polybenzoxazole-based mixed matrix membranes of the present invention can be fabricated into any convenient geometry such as flat sheet (or spiral wound), tube, hollow fiber, or thin film composite. These polybenzoxazole-based mixed matrix membranes exhibit high thermal stability, significantly higher selectivity than the neat polybenzoxazole polymer membranes, and much higher permeability than traditional mixed matrix membranes.
摘要:
The present invention provides a process for making an integrally skinned asymmetric polybenzoxazole hollow fiber membrane comprising spinning a dope solution via a dry-wet phase inversion technique to form a porous integrally skinned asymmetric o-hydroxy substituted polyimide or an o-hydroxy substituted polyamide hollow fiber membrane comprising microporous inorganic molecular sieve followed by thermal rearrangement at a temperature from about 250° to 500° C. to convert the polyimide or polyamide membrane into a polybenzoxazole membrane. These membranes contain microporous inorganic molecular sieve materials that can have a particle size from about 20 nm to 10 μm.
摘要:
This invention describes a new concept of flexible template-directed microporous partially pyrolyzed polymeric membranes which have greatly improved performance in separation of gas pairs compared to their precursor polymeric membranes. Organic hosts, such as crown ethers, cyclodextrins (CDs), calixarenes (CXs), and spherands, or polymeric additives, such as poly(ethylene glycol) (PEG) and polyvinylpyrrolidone (PVP) were used as the micropore-forming templates. Micropore-forming template/polymer blend membranes comprising organic micropore-forming templates embedded in a polymer matrix were prepared by dissolving the organic micropore-forming templates in the polymer solution followed by solution-casting and solvent evaporation or solvent exchange. Low-temperature selectively pyrolyzing micropore-forming templates in the micropore-forming template/polymer blend membranes at a nitrogen flow resulted in the formation of flexible microporous partially pyrolyzed polymeric membranes.
摘要:
The present invention discloses a new type of polyimide membranes including hollow fiber and flat sheet membranes with high permeances for air separations and a method of making these membranes. The new polyimide hollow fiber membranes have O2 permeance higher than 300 GPU and O2/N2 selectivity higher than 3 at 60° C. under 308 kPa for O2/N2 separation. The new polyimide hollow fiber membranes also have CO2 permeance higher than 1000 GPU and single-gas selectivity for CO2/CH4 higher than 20 at 50° C. under 791 kPa for CO2/CH4 separation.
摘要:
The present invention discloses high performance polybenzoxazole membranes prepared from aromatic poly(o-hydroxy amide) membranes by thermal cyclization and a method for using these membranes. The polybenzoxazole membranes were prepared by thermal treating aromatic poly(o-hydroxy amide) membranes in a temperature range of 200° to 550° C. under inert atmosphere. The aromatic poly(o-hydroxy amide) membranes used for making the polybenzoxazole membranes were prepared from aromatic poly(o-hydroxy amide) polymers comprising pendent phenolic hydroxyl groups ortho to the amide nitrogen in the polymer backbone. In some embodiments of the invention, the polybenzoxazole membranes may be subjected to an additional crosslinking step to increase the selectivity of the membranes. These polybenzoxazole membranes showed significantly improved permeability for gas separations compared to the precursor aromatic poly(o-hydroxy amide) membranes and are not only suitable for a variety of liquid, gas, and vapor separations, but also can be used in catalysis and fuel cells.
摘要:
The present invention discloses a novel method to improve the selectivities of polybenzoxazole (PBO) membranes prepared from aromatic polyimide membranes for gas, vapor, and liquid separations. The PBO membranes that were prepared by thermal treating aromatic polyimide membranes containing between 0.05 and 20 wt-% of a poly(styrene sulfonic acid) polymer. These polymers showed up to 95% improvement in selectivity for CO2/CH4 and H2/CH4 separations compared to PBO membranes prepared from corresponding aromatic polyimide membranes without a poly(styrene sulfonic acid) polymer.