PDF Publication Title:
Text from PDF Page: 165
3.2.1 Metal-Organic Frameworks (MOFs) Over the past decade, metal-organic frameworks (MOFs) have emerged as a n ew class of microporous solids exhibiting r ecord s urface a reas o f u p t o 5200 m 2/g, as well as t unable p ore si zes and su rface chemistry [59]. MOFs, also known under the names such as porous coordination polymers, are typically crystalline powders obtained from a high-dielectric solvent by reaction of a metal salt with a multitopic organic br idging l igand c apable o f l inking t he metal c ations i nto a por ous t hree-dimensional ne twork structure. Subsequent heating under dynamic vacuum or treatment by supercritical drying [60] evacuates the s olvent m olecules f rom t he por es of the s tructure w ithout de stroying t he network c onnectivity a nd crystallinity. O wing t o t heir e xceptionally h igh su rface ar eas, t hese m aterials can ex hibit t remendous capacities for compressed gas storage, delivering the highest known storage densities for CH4, C2H2, CO2, and cryogenic H2 [61]. A high surface area is also beneficial for CO2 capture, where it can ensure a high loading cap acity an d, ass uming good p ermeability, r apid ad sorption as a r esult o f t he l arge g as-solid interface. M ost i mportantly, how ever, M OFs of fer t he pos sibility of us ing t he pow er of s ynthetic chemistry to tailor the nature of their internal surfaces and thereby adjust the CO2 adsorption selectivity. MOFs a re of pot ential u tility f or c apturing C O2 under a v ariety o f sc enarios. Of p articular i nterest is capture from the flue gas emitted by fossil fuel power plants using a p ressure and/or temperature swing adsorption pr ocess. They a re additionally of i nterest f or applications in natural g as sweetening, in t he efficient capture of O2 from air for oxyfuel combustion, and in precombustion capture of CO2 from the higher pressure (50-60 bar) synthesis gas obtained upon c oal gasification. For this l ast application, further research into methods for integrating MOFs within membranes is essential. Finally, it should be noted that MOFs are also of possible value for the transport of compressed CO2 gas subsequent to capture [61c]. For ad sorptive sep arations, d ifferences i n size an d/or el ectronic p roperties c an be u tilized. T he m ajor separation issue for a flue gas with an overall pressure of 1 bar is the separation of CO2 (ca. 15-16 % by weight) from N2 (70-75%), ideally in the presence of water vapor (5-7%) and O2 (3-4%). Separations can be achieved on the basis of the smaller kinetic diameter of CO2 (3.30 Å) compared with N2 (3.64 Å), but itshould bekept inmindthat the smallpore sizesrequiredmayseverelyimpedegaspermeation. Typically, CO2 is preferentially adsorbed over N2 because it has a greater polarizability (29.1 x 10–40 cm3 vs. 17.6 x 1 0–25 cm3) and quadrupole moment (–13.4 x 10 –40 Cm2 vs. –4.7 x 1 0–25 Cm2). F or a high selectivity to be achieved, the adsorbent should have a large heat of adsorption for CO2 compared with the other gases; however, increases in selectivity will also come with a p enalty in the energy required to release the CO2 and regenerate the adsorbent. Structural Considerations: The following are some structural issues worthy of consideration in attempting to design MOFS suitable for CO2 capture from flue gas. Surface area. As mentioned, the very high surface areas of MOFs can be an advantage for achieving a high gravimetric CO2 adsorption capacity. Surface areas in excess of 4000 m2/g have been reported for a number of M OFs [ 62]. When m aking c omparisons of s urface a reas, h owever, one m ust be c areful t o ensure that the values have been calculated correctly [63]. Of course, it is also important that the exposed surface area within a MOF have a strong affinity for CO2 if a high loading capacity is to be achieved at the relevant partial pressure of 0.1 bar. Pore size. MOFs featuringsmallporeopeningscanservetogiveselectivityforCO2 overN2 by restricting ac cess t o t he larger N 2 molecules. F or e xample, M n(HCO2)2 with 4.5 -Å zi g-zag c hannels exhibits a 10-fold selectivity for adsorbing CO2 over N2 or CH4 at 1 bar and 195 K [64] To obtain narrow pores, on e c an u tilize short br idging l igands, s uch a s f ormate in this e xample, or r ely upon interpenetration, wherein two or more distinct networks are interwoven. Another means of using pore Carbon Capture Factual Document 27PDF Image | 2020 Carbon Capture
PDF Search Title:
2020 Carbon CaptureOriginal File Name Searched:
1291240.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)