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Supercritical carbon dioxide

February 05, 2023

Supercritical carbon dioxide (sCO
2) is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.

Carbon dioxide pressure-temperature phase diagram

Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as a solid called dry ice when cooled and/or pressurised sufficiently. If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide, it can adopt properties midway between a gas and a liquid. More specifically, it behaves as a supercritical fluid above its critical temperature (304.128 K, 30.9780 °C, 87.7604 °F)[1] and critical pressure (7.3773 MPa, 72.808 atm, 1,070.0 psi, 73.773 bar),[1] expanding to fill its container like a gas but with a density like that of a liquid.

Supercritical CO
2 is becoming an important commercial and industrial solvent due to its role in chemical extraction in addition to its relatively low toxicity and environmental impact. The relatively low temperature of the process and the stability of CO
2 also allows most compounds to be extracted with little damage or denaturing. In addition, the solubility of many extracted compounds in CO
2 varies with pressure,[2] permitting selective extractions.

Applications

Solvent

Main article: Supercritical fluid extraction

Carbon dioxide is gaining popularity among coffee manufacturers looking to move away from classic decaffeinating solvents. sCO
2 is forced through the green coffee beans which are then sprayed with water at high pressure to remove the caffeine. The caffeine can then be isolated for resale (e.g. to the pharmaceutical or beverage manufacturers) by passing the water through activated charcoal filters or by distillation, crystallization or reverse osmosis. Supercritical carbon dioxide is used to remove organochloride pesticides and metals from agricultural crops without adulterating the desired constituents from the plant matter in the herbal supplement industry.[3]

Supercritical carbon dioxide can be used as a more environmentally friendly solvent for dry cleaning over traditional solvents such as chlorocarbons, including perchloroethylene.[4]

Supercritical carbon dioxide is used as the extraction solvent for creation of essential oils and other herbal distillates.[5] Its main advantages over solvents such as hexane and acetone in this process are that it is non-flammable and does not leave toxic residue. Furthermore, separation of the reaction components from the starting material is much simpler than with traditional organic solvents. The CO
2 can evaporate into the air or be recycled by condensation into a cold recovery vessel. Its advantage over steam distillation is that it operates at a lower temperature, which can separate the plant waxes from the oils.[6]

In laboratories, sCO
2 is used as an extraction solvent, for example for determining total recoverable hydrocarbons from soils, sediments, fly-ash and other media,[7] and determination of polycyclic aromatic hydrocarbons in soil and solid wastes.[8] Supercritical fluid extraction has been used in determining hydrocarbon components in water.[9]

Processes that use sCO
2 to produce micro and nano scale particles, often for pharmaceutical uses, are under development. The gas antisolvent process, rapid expansion of supercritical solutions and supercritical antisolvent precipitation (as well as several related methods) process a variety of substances into particles.[10]

Due to its ability to selectively dissolve organic compounds and assist the functioning of enzymes, sCO
2 has been suggested as a potential solvent to support biological activity on Venus- or super-Earth-type planets.[11]

Manufactured products

Environmentally beneficial, low-cost substitutes for rigid thermoplastic and fired ceramic are made using sCO
2 as a chemical reagent. The sCO
2 in these processes is reacted with the alkaline components of fully hardened hydraulic cement or gypsum plaster to form various carbonates.[12] The primary byproduct is water.

Supercritical carbon dioxide is used in the foaming of polymers. Supercritical carbon dioxide can saturate the polymer with solvent. Upon depressurization and heating the carbon dioxide rapidly expands, causing voids within the polymer matrix, i.e., creating a foam. Research is also ongoing at many universities in the production of microcellular foams using sCO
2.

An electrochemical carboxylation of a para-isobutylbenzyl chloride to ibuprofen is promoted under sCO
2.[13]

Working fluid

Supercritical CO
2 is chemically stable, reliable, low-cost, non-flammable and readily available, making it a desirable candidate working fluid for transcritical cycles.[14]

Supercritical CO2 is used as the working fluid in high efficiency domestic water heat pumps. Manufactured and widely used, heat pumps are also commercially available for domestic and business heating and cooling.[14] While some of the more common domestic water heat pumps remove heat from the space in which they are located, such as a basement or garage, the CO2 heat pump water heaters are typically located outside, where they remove heat from the outside air.[14]

Power generation

The unique properties of sCO
2 present advantages for closed-loop power generation and can be applied to various power generation applications. Power generation systems that use traditional air Brayton and steam Rankine cycles can be upgraded to sCO
2 to increase efficiency and power output.

The relatively new Allam power cycle uses sCO2 as the working fluid in combination with fuel and pure oxygen. The CO2 produced by combustion mixes with the sCO2 working fluid and a corresponding amount of pure CO2 must be removed from the process (for industrial use or sequestration). This process reduces atmospheric emissions to zero.

It presents interesting properties that promise substantial improvements in system efficiency. Due to its high fluid density, sCO2 enables extremely compact and highly efficient turbomachinery. It can use simpler, single casing body designs while steam turbines require multiple turbine stages and associated casings, as well as additional inlet and outlet piping. The high density allows for highly compact, microchannel-based heat exchanger technology.[15]

In 2016, General Electric announced a super-critical CO2 based turbine that enabled a 50% efficiency of converting heat energy to electrical energy. In it the CO2 is heated to 700 °C. It requires less compression and allows heat transfer. It reaches full power in 2 minutes, whereas steam turbines need at least 30 minutes. The prototype generated 10 MW and is approximately 10% the size of a comparable steam turbine.[16]

For concentrated solar power, carbon dioxide critical temperature is not high enough to obtain the maximum energy conversion efficiency. Solar thermal plants are usually located in arid areas, so it is impossible to cool down the heat sink to sub-critical temperatures. Therefore, supercritical carbon dioxide blends, with higher critical temperatures, are in development to improve concentrated solar power electricity production.

Further, due to its superior thermal stability and non-flammability, direct heat exchange from high temperature sources is possible, permitting higher working fluid temperatures and therefore higher cycle efficiency. Unlike two-phase flow, the single-phase nature of sCO
2 eliminates the necessity of a heat input for phase change that is required for the water to steam conversion, thereby also eliminating associated thermal fatigue and corrosion.[17]

Despite the promise of substantially higher efficiency and lower capital costs, the use of sCO
2 presents corrosion engineering, material selection and design issues. Materials in power generation components must display resistance to damage caused by high-temperature, oxidation and creep. Candidate materials that meet these property and performance goals include incumbent alloys in power generation, such as nickel-based superalloys for turbomachinery components and austenitic stainless steels for piping. Components within sCO
2 Brayton loops suffer from corrosion and erosion, specifically erosion in turbomachinery and recuperative heat exchanger components and intergranular corrosion and pitting in the piping.[18]

Testing has been conducted on candidate Ni-based alloys, austenitic steels, ferritic steels and ceramics for corrosion resistance in sCO
2 cycles. The interest in these materials derive from their formation of protective surface oxide layers in the presence of carbon dioxide, however in most cases further evaluation of the reaction mechanics and corrosion/erosion kinetics and mechanisms is required, as none of the materials meet the necessary goals.[19][20]

Other

Work is underway to develop a sCO
2 closed-cycle gas turbine to operate at temperatures near 550 °C. This would have implications for bulk thermal and nuclear generation of electricity, because the supercritical properties of carbon dioxide at above 500 °C and 20 MPa enable thermal efficiencies approaching 45 percent. This could increase the electrical power produced per unit of fuel required by 40 percent or more. Given the volume of carbon fuels used in producing electricity, the environmental impact of cycle efficiency increases would be significant.[21]

Supercritical CO
2 is an emerging natural refrigerant, used in new, low carbon solutions for domestic heat pumps. Supercritical CO
2 heat pumps are commercially marketed in Asia. EcoCute systems from Japan, developed by Mayekawa, develop high temperature domestic water with small inputs of electric power by moving heat into the system from the surroundings.[22]

Supercritical CO
2 has been used since the 1980s to enhance recovery in mature oil fields.

"Clean coal" technologies are emerging that could combine such enhanced recovery methods with carbon sequestration. Using gasifiers instead of conventional furnaces, coal and water is reduced to hydrogen gas, carbon dioxide and ash. This hydrogen gas can be used to produce electrical power In combined cycle gas turbines, CO
2 is captured, compressed to the supercritical state and injected into geological storage, possibly into existing oil fields to improve yields. The unique properties of sCO
2 ensure that it remains out of the atmosphere.[23][24][25]

Supercritical CO
2 can be used as a working fluid for geothermal electricity generation in both enhanced geothermal systems[26][27][28][29] and sedimentary geothermal systems (so-called CO
2 Plume Geothermal).[30][31] EGS systems utilize an artificially fractured reservoir in basement rock while CPG systems utilize shallower naturally-permeable sedimentary reservoirs. Possible advantages of using CO
2 in a geologic reservoir, compared to water, include higher energy yield resulting from its lower viscosity, better chemical interaction, and permanent CO
2 storage as the reservoir must be filled with large masses of CO
2. As of 2011, the concept had not been tested in the field.[32]

Aerogel production

Supercritical carbon dioxide is used in the production of silica, carbon and metal based aerogels. For example, silicon dioxide gel is formed and then exposed to sCO
2. When the CO
2 goes supercritical, all surface tension is removed, allowing the liquid to leave the aerogel and produce nanometer sized pores.[33]

Sterilization of biomedical materials

Supercritical CO
2 is an alternative for thermal sterilization of biological materials and medical devices with combination of the additive peracetic acid (PAA). Supercritical CO
2 does not sterilize the media, because it does not kill the spores of microorganisms. Moreover, this process is gentle, as the morphology, ultrastructure and protein profiles of inactivated microbes are preserved.[34]

Cleaning

Supercritical CO
2 is used in certain industrial cleaning processes.

See also

References

  1. ^ a b Span, Roland; Wagner, Wolfgang (1996). "A New Equation of State for Carbon Dioxide Covering the Fluid Region from the Triple‐Point Temperature to 1100 K at Pressures up to 800 MPa". Journal of Physical and Chemical Reference Data. 25 (6): 1509–1596. Bibcode:1996JPCRD..25.1509S. doi:10.1063/1.555991.
  2. ^ Discovery - Can Chemistry Save The World? - BBC World Service
  3. ^ Department of Pharmaceutical Analysis, Shenyang Pharmaceutical University, Shenyang 110016, China
  4. ^ Stewart, Gina (2003), Joseph M. DeSimone; William Tumas (eds.), "Dry Cleaning with Liquid Carbon Dioxide", Green Chemistry Using Liquid and SCO
    2    : 215–227
  5. ^ Aizpurua-Olaizola, Oier; Ormazabal, Markel; Vallejo, Asier; Olivares, Maitane; Navarro, Patricia; Etxebarria, Nestor; Usobiaga, Aresatz (1 January 2015). "Optimization of supercritical fluid consecutive extractions of fatty acids and polyphenols from Vitis vinifera grape wastes". Journal of Food Science. 80 (1): E101–107. doi:10.1111/1750-3841.12715. ISSN 1750-3841. PMID 25471637.
  6. ^ Mendiola, J.A.; Herrero, M.; Cifuentes, A.; Ibañez, E. (2007). "Use of compressed fluids for sample preparation: Food applications". Journal of Chromatography A. 1152 (1–2): 234–246. doi:10.1016/j.chroma.2007.02.046. hdl:10261/12445. PMID 17353022.
  7. ^ "Test Methods | Wastes - Hazardous Waste | US EPA". wayback.archive-it.org.
  8. ^ U.S.EPA Method 3561 Supercritical Fluid Extraction of Polycyclic Aromatic Hydrocarbons.
  9. ^ Use of Ozone Depleting Substances in Laboratories. TemaNord 2003:516.
  10. ^ Yeo, S.; Kiran, E. (2005). "Formation of polymer particles with supercritical fluids: A review". J. Supercrit. Fluids. 34 (3): 287–308. doi:10.1016/j.supflu.2004.10.006.
  11. ^ Budisa, Nediljko; Schulze-Makuch, Dirk (8 August 2014). "Supercritical Carbon Dioxide and Its Potential as a Life-Sustaining Solvent in a Planetary Environment". Life. 4 (3): 331–340. doi:10.3390/life4030331. PMC 4206850. PMID 25370376.
  12. ^ Rubin, James B.; Taylor, Craig M. V.; Hartmann, Thomas; Paviet-Hartmann, Patricia (2003), Joseph M. DeSimone; William Tumas (eds.), "Enhancing the Properties of Portland Cements Using Supercritical Carbon Dioxide", Green Chemistry Using Liquid and Supercritical Carbon Dioxide: 241–255
  13. ^ Sakakura, Toshiyasu; Choi, Jun-Chul; Yasuda, Hiroyuki (13 June 2007). "Transformation of Carbon dioxide". Chemical Reviews. 107 (6): 2365–2387. doi:10.1021/cr068357u. PMID 17564481.
  14. ^ a b c Ma, Yitai; Liu, Zhongyan; Tian, Hua (2013). "A review of transcritical carbon dioxide heat pump and refrigeration cycles". Energy. 55: 156–172. doi:10.1016/j.energy.2013.03.030. ISSN 0360-5442.
  15. ^ "Supercritical CO2 Power Cycle Developments and Commercialization: Why sCO2 can Displace Steam" (PDF).
  16. ^ Talbot, David (11 April 2016). "Desk-Size Turbine Could Power a Town". MIT Technology Review. Retrieved 13 April 2016.
  17. ^ "Supercritical Carbon Dioxide Power Cycles Starting to Hit the Market". Breaking Energy.
  18. ^ "Corrosion and Erosion Behavior in sCO
    2     Power Cycles" (PDF). Sandia National Laboratories.
  19. ^ (PDF). The 4th International Symposium - Supercritical CO2 Power Cycles. Archived from the original (PDF) on 23 April 2016.
  20. ^ J. Parks, Curtis. "Corrosion of Candidate High Temperature Alloys in Supercritical Carbon Dioxide" (PDF). Ottawa-Carleton Institute for Mechanical and Aerospace Engineering.
  21. ^ V. Dostal, M.J. Driscoll, P. Hejzlar, "A Supercritical Carbon Dioxide Cycle for Next Generation Nuclear Reactors" (PDF). Retrieved 20 November 2007. MIT-ANP-Series, MIT-ANP-TR-100 (2004)
  22. ^ "Heat Pumps". Mayekawa Manufacturing Company (Mycom). Retrieved 7 February 2015.
  23. ^ "The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs", p. 84 (2004)
  24. ^ . FutureGen Alliance. Archived from the original on 10 February 2015. Retrieved 7 February 2015.
  25. ^ . Archived from the original on 29 September 2007.
  26. ^ K Pruess(2006), "A hot dry rock geothermal energy concept utilizing sCO
    2     instead of water" 2011-10-08 at the Wayback Machine
  27. ^ Donald W. Brown(2000), "On the feasibility of using sCO
    2     as heat transmission fluid in an engineered hot dry rock geothermal system" 2006-09-04 at the Wayback Machine
  28. ^ K Pruess(2007)Enhanced Geothermal Systems (EGS) comparing water with CO
    2     as heat transmission fluids"
  29. ^ J Apps(2011), "Modeling geochemical processes in enhanced geothermal systems with CO
    2     as heat transfert fluid"
  30. ^ Randolph, Jimmy B.; Saar, Martin O. (2011). "Combining geothermal energy capture with geologic carbon dioxide sequestration". Geophysical Research Letters. 38 (L10401): n/a. Bibcode:2011GeoRL..3810401R. doi:10.1029/2011GL047265.
  31. ^ Adams, Benjamin M.; Kuehn, Thomas H.; Bielicki, Jeffrey M.; Randolph, Jimmy B.; Saar, Martin O. (2015). "A comparison of electric power output of CO2 Plume Geothermal (CPG) and brine geothermal systems for varying reservoir conditions". Applied Energy. 140: 365–377. doi:10.1016/j.apenergy.2014.11.043.
  32. ^ http://earthsciences.typepad.com/blog/2011/06/achieving-carbon-sequestration-and-geothermal-energy-production-a-win-win.html ESD News and Events "Achieving Carbon Sequestration and Geothermal Energy Production: A Win-Win!"
  33. ^ "Aerogel.org » Supercritical Drying".
  34. ^ White, Angela; Burns, David; Christensen, Tim W. (2006). "Effective terminal sterilization using supercritical carbon dioxide". Journal of Biotechnology. 123 (4): 504–515. doi:10.1016/j.jbiotec.2005.12.033. PMID 16497403.

Further reading

  • Mukhopadhyay M. (2000). Natural extracts using supercritical carbon dioxide. United States: CRC Press, LLC. Free preview at Google Books.

February 05, 2023
supercritical, carbon, dioxide, sco2, fluid, state, carbon, dioxide, where, held, above, critical, temperature, critical, pressure, carbon, dioxide, pressure, temperature, phase, diagram, carbon, dioxide, usually, behaves, standard, temperature, pressure, soli. Supercritical carbon dioxide sCO2 is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure Carbon dioxide pressure temperature phase diagram Carbon dioxide usually behaves as a gas in air at standard temperature and pressure STP or as a solid called dry ice when cooled and or pressurised sufficiently If the temperature and pressure are both increased from STP to be at or above the critical point for carbon dioxide it can adopt properties midway between a gas and a liquid More specifically it behaves as a supercritical fluid above its critical temperature 304 128 K 30 9780 C 87 7604 F 1 and critical pressure 7 3773 MPa 72 808 atm 1 070 0 psi 73 773 bar 1 expanding to fill its container like a gas but with a density like that of a liquid Supercritical CO2 is becoming an important commercial and industrial solvent due to its role in chemical extraction in addition to its relatively low toxicity and environmental impact The relatively low temperature of the process and the stability of CO2 also allows most compounds to be extracted with little damage or denaturing In addition the solubility of many extracted compounds in CO2 varies with pressure 2 permitting selective extractions Contents 1 Applications 1 1 Solvent 1 2 Manufactured products 1 3 Working fluid 1 3 1 Power generation 1 3 2 Other 1 4 Aerogel production 1 5 Sterilization of biomedical materials 1 6 Cleaning 2 See also 3 References 4 Further readingApplications EditSolvent Edit Main article Supercritical fluid extraction Carbon dioxide is gaining popularity among coffee manufacturers looking to move away from classic decaffeinating solvents sCO2 is forced through the green coffee beans which are then sprayed with water at high pressure to remove the caffeine The caffeine can then be isolated for resale e g to the pharmaceutical or beverage manufacturers by passing the water through activated charcoal filters or by distillation crystallization or reverse osmosis Supercritical carbon dioxide is used to remove organochloride pesticides and metals from agricultural crops without adulterating the desired constituents from the plant matter in the herbal supplement industry 3 Supercritical carbon dioxide can be used as a more environmentally friendly solvent for dry cleaning over traditional solvents such as chlorocarbons including perchloroethylene 4 Supercritical carbon dioxide is used as the extraction solvent for creation of essential oils and other herbal distillates 5 Its main advantages over solvents such as hexane and acetone in this process are that it is non flammable and does not leave toxic residue Furthermore separation of the reaction components from the starting material is much simpler than with traditional organic solvents The CO2 can evaporate into the air or be recycled by condensation into a cold recovery vessel Its advantage over steam distillation is that it operates at a lower temperature which can separate the plant waxes from the oils 6 In laboratories sCO2 is used as an extraction solvent for example for determining total recoverable hydrocarbons from soils sediments fly ash and other media 7 and determination of polycyclic aromatic hydrocarbons in soil and solid wastes 8 Supercritical fluid extraction has been used in determining hydrocarbon components in water 9 Processes that use sCO2 to produce micro and nano scale particles often for pharmaceutical uses are under development The gas antisolvent process rapid expansion of supercritical solutions and supercritical antisolvent precipitation as well as several related methods process a variety of substances into particles 10 Due to its ability to selectively dissolve organic compounds and assist the functioning of enzymes sCO2 has been suggested as a potential solvent to support biological activity on Venus or super Earth type planets 11 Manufactured products Edit Environmentally beneficial low cost substitutes for rigid thermoplastic and fired ceramic are made using sCO2 as a chemical reagent The sCO2 in these processes is reacted with the alkaline components of fully hardened hydraulic cement or gypsum plaster to form various carbonates 12 The primary byproduct is water Supercritical carbon dioxide is used in the foaming of polymers Supercritical carbon dioxide can saturate the polymer with solvent Upon depressurization and heating the carbon dioxide rapidly expands causing voids within the polymer matrix i e creating a foam Research is also ongoing at many universities in the production of microcellular foams using sCO2 An electrochemical carboxylation of a para isobutylbenzyl chloride to ibuprofen is promoted under sCO2 13 Working fluid Edit Supercritical CO2 is chemically stable reliable low cost non flammable and readily available making it a desirable candidate working fluid for transcritical cycles 14 Supercritical CO2 is used as the working fluid in high efficiency domestic water heat pumps Manufactured and widely used heat pumps are also commercially available for domestic and business heating and cooling 14 While some of the more common domestic water heat pumps remove heat from the space in which they are located such as a basement or garage the CO2 heat pump water heaters are typically located outside where they remove heat from the outside air 14 Power generation Edit The unique properties of sCO2 present advantages for closed loop power generation and can be applied to various power generation applications Power generation systems that use traditional air Brayton and steam Rankine cycles can be upgraded to sCO2 to increase efficiency and power output The relatively new Allam power cycle uses sCO2 as the working fluid in combination with fuel and pure oxygen The CO2 produced by combustion mixes with the sCO2 working fluid and a corresponding amount of pure CO2 must be removed from the process for industrial use or sequestration This process reduces atmospheric emissions to zero It presents interesting properties that promise substantial improvements in system efficiency Due to its high fluid density sCO2 enables extremely compact and highly efficient turbomachinery It can use simpler single casing body designs while steam turbines require multiple turbine stages and associated casings as well as additional inlet and outlet piping The high density allows for highly compact microchannel based heat exchanger technology 15 In 2016 General Electric announced a super critical CO2 based turbine that enabled a 50 efficiency of converting heat energy to electrical energy In it the CO2 is heated to 700 C It requires less compression and allows heat transfer It reaches full power in 2 minutes whereas steam turbines need at least 30 minutes The prototype generated 10 MW and is approximately 10 the size of a comparable steam turbine 16 For concentrated solar power carbon dioxide critical temperature is not high enough to obtain the maximum energy conversion efficiency Solar thermal plants are usually located in arid areas so it is impossible to cool down the heat sink to sub critical temperatures Therefore supercritical carbon dioxide blends with higher critical temperatures are in development to improve concentrated solar power electricity production Further due to its superior thermal stability and non flammability direct heat exchange from high temperature sources is possible permitting higher working fluid temperatures and therefore higher cycle efficiency Unlike two phase flow the single phase nature of sCO2 eliminates the necessity of a heat input for phase change that is required for the water to steam conversion thereby also eliminating associated thermal fatigue and corrosion 17 Despite the promise of substantially higher efficiency and lower capital costs the use of sCO2 presents corrosion engineering material selection and design issues Materials in power generation components must display resistance to damage caused by high temperature oxidation and creep Candidate materials that meet these property and performance goals include incumbent alloys in power generation such as nickel based superalloys for turbomachinery components and austenitic stainless steels for piping Components within sCO2 Brayton loops suffer from corrosion and erosion specifically erosion in turbomachinery and recuperative heat exchanger components and intergranular corrosion and pitting in the piping 18 Testing has been conducted on candidate Ni based alloys austenitic steels ferritic steels and ceramics for corrosion resistance in sCO2 cycles The interest in these materials derive from their formation of protective surface oxide layers in the presence of carbon dioxide however in most cases further evaluation of the reaction mechanics and corrosion erosion kinetics and mechanisms is required as none of the materials meet the necessary goals 19 20 Other Edit Work is underway to develop a sCO2 closed cycle gas turbine to operate at temperatures near 550 C This would have implications for bulk thermal and nuclear generation of electricity because the supercritical properties of carbon dioxide at above 500 C and 20 MPa enable thermal efficiencies approaching 45 percent This could increase the electrical power produced per unit of fuel required by 40 percent or more Given the volume of carbon fuels used in producing electricity the environmental impact of cycle efficiency increases would be significant 21 Supercritical CO2 is an emerging natural refrigerant used in new low carbon solutions for domestic heat pumps Supercritical CO2 heat pumps are commercially marketed in Asia EcoCute systems from Japan developed by Mayekawa develop high temperature domestic water with small inputs of electric power by moving heat into the system from the surroundings 22 Supercritical CO2 has been used since the 1980s to enhance recovery in mature oil fields Clean coal technologies are emerging that could combine such enhanced recovery methods with carbon sequestration Using gasifiers instead of conventional furnaces coal and water is reduced to hydrogen gas carbon dioxide and ash This hydrogen gas can be used to produce electrical power In combined cycle gas turbines CO2 is captured compressed to the supercritical state and injected into geological storage possibly into existing oil fields to improve yields The unique properties of sCO2 ensure that it remains out of the atmosphere 23 24 25 Supercritical CO2 can be used as a working fluid for geothermal electricity generation in both enhanced geothermal systems 26 27 28 29 and sedimentary geothermal systems so called CO2 Plume Geothermal 30 31 EGS systems utilize an artificially fractured reservoir in basement rock while CPG systems utilize shallower naturally permeable sedimentary reservoirs Possible advantages of using CO2 in a geologic reservoir compared to water include higher energy yield resulting from its lower viscosity better chemical interaction and permanent CO2 storage as the reservoir must be filled with large masses of CO2 As of 2011 the concept had not been tested in the field 32 Aerogel production Edit Supercritical carbon dioxide is used in the production of silica carbon and metal based aerogels For example silicon dioxide gel is formed and then exposed to sCO2 When the CO2 goes supercritical all surface tension is removed allowing the liquid to leave the aerogel and produce nanometer sized pores 33 Sterilization of biomedical materials Edit Supercritical CO2 is an alternative for thermal sterilization of biological materials and medical devices with combination of the additive peracetic acid PAA Supercritical CO2 does not sterilize the media because it does not kill the spores of microorganisms Moreover this process is gentle as the morphology ultrastructure and protein profiles of inactivated microbes are preserved 34 Cleaning Edit Supercritical CO2 is used in certain industrial cleaning processes See also EditCaffeine Dry cleaning Perfume Supercritical fluid Atmosphere of Venus nearly all carbon dioxide supercritical at the surfaceReferences Edit a b Span Roland Wagner Wolfgang 1996 A New Equation of State for Carbon Dioxide Covering the Fluid Region from the Triple Point Temperature to 1100 K at Pressures up to 800 MPa Journal of Physical and Chemical Reference Data 25 6 1509 1596 Bibcode 1996JPCRD 25 1509S doi 10 1063 1 555991 Discovery Can Chemistry Save The World BBC World Service Department of Pharmaceutical Analysis Shenyang Pharmaceutical University Shenyang 110016 China Stewart Gina 2003 Joseph M DeSimone William Tumas eds Dry Cleaning with Liquid Carbon Dioxide Green Chemistry Using Liquid and SCO2 215 227 Aizpurua Olaizola Oier Ormazabal Markel Vallejo Asier Olivares Maitane Navarro Patricia Etxebarria Nestor Usobiaga Aresatz 1 January 2015 Optimization of supercritical fluid consecutive extractions of fatty acids and polyphenols from Vitis vinifera grape wastes Journal of Food Science 80 1 E101 107 doi 10 1111 1750 3841 12715 ISSN 1750 3841 PMID 25471637 Mendiola J A Herrero M Cifuentes A Ibanez E 2007 Use of compressed fluids for sample preparation Food applications Journal of Chromatography A 1152 1 2 234 246 doi 10 1016 j chroma 2007 02 046 hdl 10261 12445 PMID 17353022 Test Methods Wastes Hazardous Waste US EPA wayback archive it org U S EPA Method 3561 Supercritical Fluid Extraction of Polycyclic Aromatic Hydrocarbons Use of Ozone Depleting Substances in Laboratories TemaNord 2003 516 Yeo S Kiran E 2005 Formation of polymer particles with supercritical fluids A review J Supercrit Fluids 34 3 287 308 doi 10 1016 j supflu 2004 10 006 Budisa Nediljko Schulze Makuch Dirk 8 August 2014 Supercritical Carbon Dioxide and Its Potential as a Life Sustaining Solvent in a Planetary Environment Life 4 3 331 340 doi 10 3390 life4030331 PMC 4206850 PMID 25370376 Rubin James B Taylor Craig M V Hartmann Thomas Paviet Hartmann Patricia 2003 Joseph M DeSimone William Tumas eds Enhancing the Properties of Portland Cements Using Supercritical Carbon Dioxide Green Chemistry Using Liquid and Supercritical Carbon Dioxide 241 255 Sakakura Toshiyasu Choi Jun Chul Yasuda Hiroyuki 13 June 2007 Transformation of Carbon dioxide Chemical Reviews 107 6 2365 2387 doi 10 1021 cr068357u PMID 17564481 a b c Ma Yitai Liu Zhongyan Tian Hua 2013 A review of transcritical carbon dioxide heat pump and refrigeration cycles Energy 55 156 172 doi 10 1016 j energy 2013 03 030 ISSN 0360 5442 Supercritical CO2 Power Cycle Developments and Commercialization Why sCO2 can Displace Steam PDF Talbot David 11 April 2016 Desk Size Turbine Could Power a Town MIT Technology Review Retrieved 13 April 2016 Supercritical Carbon Dioxide Power Cycles Starting to Hit the Market Breaking Energy Corrosion and Erosion Behavior in sCO2 Power Cycles PDF Sandia National Laboratories THE EFFECT OF TEMPERATURE ON THE sCO2 COMPATIBILITY OF CONVENTIONAL STRUCTURAL ALLOYS PDF The 4th International Symposium Supercritical CO2 Power Cycles Archived from the original PDF on 23 April 2016 J Parks Curtis Corrosion of Candidate High Temperature Alloys in Supercritical Carbon Dioxide PDF Ottawa Carleton Institute for Mechanical and Aerospace Engineering V Dostal M J Driscoll P Hejzlar A Supercritical Carbon Dioxide Cycle for Next Generation Nuclear Reactors PDF Retrieved 20 November 2007 MIT ANP Series MIT ANP TR 100 2004 Heat Pumps Mayekawa Manufacturing Company Mycom Retrieved 7 February 2015 The Hydrogen Economy Opportunities Costs Barriers and R amp D Needs p 84 2004 FutureGen 2 0 Project FutureGen Alliance Archived from the original on 10 February 2015 Retrieved 7 February 2015 Oyvind Vessia Fischer Tropsch reactor fed by syngas Archived from the original on 29 September 2007 K Pruess 2006 A hot dry rock geothermal energy concept utilizing sCO2 instead of water Archived 2011 10 08 at the Wayback Machine Donald W Brown 2000 On the feasibility of using sCO2 as heat transmission fluid in an engineered hot dry rock geothermal system Archived 2006 09 04 at the Wayback Machine K Pruess 2007 Enhanced Geothermal Systems EGS comparing water with CO2 as heat transmission fluids J Apps 2011 Modeling geochemical processes in enhanced geothermal systems with CO2 as heat transfert fluid Randolph Jimmy B Saar Martin O 2011 Combining geothermal energy capture with geologic carbon dioxide sequestration Geophysical Research Letters 38 L10401 n a Bibcode 2011GeoRL 3810401R doi 10 1029 2011GL047265 Adams Benjamin M Kuehn Thomas H Bielicki Jeffrey M Randolph Jimmy B Saar Martin O 2015 A comparison of electric power output of CO2 Plume Geothermal CPG and brine geothermal systems for varying reservoir conditions Applied Energy 140 365 377 doi 10 1016 j apenergy 2014 11 043 http earthsciences typepad com blog 2011 06 achieving carbon sequestration and geothermal energy production a win win html ESD News and Events Achieving Carbon Sequestration and Geothermal Energy Production A Win Win Aerogel org Supercritical Drying White Angela Burns David Christensen Tim W 2006 Effective terminal sterilization using supercritical carbon dioxide Journal of Biotechnology 123 4 504 515 doi 10 1016 j jbiotec 2005 12 033 PMID 16497403 Further reading EditMukhopadhyay M 2000 Natural extracts using supercritical carbon dioxide United States CRC Press LLC Free preview at Google Books Retrieved from https en wikipedia org w index php title Supercritical carbon dioxide amp oldid 1133422628, wikipedia, wiki, book, books, library,

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