Microporous Crystalline Molecular Sieve Membranes for Molecular Gas Separations: What Is Next?
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H 2 S/CH 4 and CO 2 /CH 4 separations show opposing trends, making simultaneous improvement challenging. This is addressed by increasing free volume to enhance competitive sorption effects and boosting diffusion selectivity through in situ crosslinking.
Abstract not provided.
Abstract not provided.
This project devised a computational framework for simultaneously co-optimizing pressure swing adsorption process designs along with the sorbent materials (specifically, metal-organic frameworks) to be employed in the associated packed bed columns. The materials optimization aspect involved search over a design space that can describe the material’s molecular structure, while the process optimization aspect considered various process degrees of freedom for steps arising in various cycle configurations. This framework was demonstrated on the separation of nitrogen and carbon dioxide, which arises ubiquitously in a multitude of post-combustion carbon capture and “blue” hydrogen production applications. Our results led to metal-organic framework molecular descriptor choices that are predicted to outperform standard structures used in practice, providing guidance for future metal-organic framework synthesis efforts.
This presentation includes highlights from several MOF modeling projects using methods from high-throughput computations using fixed-atom classical potentials to the development of a flexible machine learned force field for a single MOF.
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Explore the source record for details and available documents.
An electrochemical nitrogen-hydrogen separator subsystem was investigated for use following catalytic dissociation of ammonia or hydrazine in a storage system being considered for long-duration manned space flight. An experimental cell with concentric tubular Pd-25Ag alloy hydrogen diffusion electrodes and hermetically sealed aqueous caustic electrolyte was developed.It was found that this cell operated satisfactorily at 210 C to 245 C and produced dry nitrogen and dry hydrogen with either or both gases at pressures up to 6.8 atmospheres (100 psia) or higher for storage. The final cell developed was operated satisfactorily for 176 days (4200 hours) with no evidence of deterioration of current-voltage performance. The best experimental performance was obtained at 245 C at currents up to 4 amperes (180 ma/sq cm and 360 ma/sq cm anode and cathode current densities, respectively) with a maximum steady-state cell voltage of 0.125 volt for an anode feed of pure hydrogen.
Cryogenic technique recovers gases inexpensively. Method uses differences in vapor pressures, melting points, and boiling points of components in gaseous mixture. Series of temperature and pressure variations converts gases independently to solid and liquid states, thereby simplifying separation. Apparatus uses readily available cryogen and does not require expensive refrigeration equipment.
This presentation, given at the 37 th annual Pittsburgh Coal Conference on September 8-11, 2020, includes information on the process, previous work, normal and oblique shocks model, diffuser design model, and calculation results (expansion, recompression with no losses, and recompression with mass depletion). Summary includes the concept of aerodynamic separation of water and carbon dioxide from a SYNGAS stream and that deposition was modeled by mass depletion from a compressible flow.
Gordon Research Conferences on Membranes, New London, NH, July 31-August 5, 2022
Accordingly, it is an object of this disclosure to provide a blend polymeric membrane to provide the separation of CO2 from a gaseous mixture. The blend polymeric membrane comprises a blend of polyphosphazene and polymers of intrinsic microporosity. Further, the present disclosure also provides a method of use for the blend polymeric membrane for the separation of gases in a gaseous mixture.
Polymer blends comprising an ortho-functionalized polyimide homo or copolymer and a polybenzimidazole homo or copolymer, wherein the ortho-functionalized polyimide thermally rearranges to a polymer comprising a phenylene heterocyclic group, such as, polybenzoxazole, polybenzothiazole, polybenzimidazole and/or other heterocyclic structure upon heating. Also disclosed are method of forming a polymer blend comprising dissolving an ortho-functionalized polyimide homo or copolymer and a polybenzimidazole homo or copolymer in a solvent, and optional compatibilizer, to form a polymer solution; contacting a support with the polymer solution; and evaporating the solvent to provide a thin layer comprising the polymer blend on the support. Further, methods of heat treating these polymer blends to thermally rearrange the disclosed polyimides are disclosed, as are the polymer blends prepared thereby. Methods of using these polymer blends to separate gases are also disclosed.
Poster for the 2023 FECM Carbon Management Review Meeting, Pittsburgh, PA, August 28-September 1, 2023.
Abstract not provided.
The North American Membrane Society (NAMS) 32nd Annual Meeting, Tuscaloosa, AL, May 14-17, 2023