Key words: supercritical fluids, thermal conductivity, hydrocarbons
Theoretical and experimental studies of combined radiation-conduction heat transfer in flat layers of hydrocarbons in sub- and supercritical regions of parameters are reviewed. Within a narrow temperature region around the critical point the radiation constituent of thermal conductivity approaches nil, but outside it the radiant flux can be comparable with the conductive one. It must be noted that this important factor must be taken into account while the equipment for several processes involving hydrocarbons is developed. This is of special importance for such processes as heavy oil treatments and fractionation, which employ propane, pentane, hexane, toluene and other hydrocarbons in sub- and supercritical state. The neglect of this factor may lead to non-optimal and even incorrect technical solutions and also to unjustified material and energetic expenses on the stage of industrial implementation.
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ГОСТ
7.0.100-2018
Combined Radiation-Conduction Heat Transfer in Sub- and Supercritical Fluid Media / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 3-15. - DOI:
TRANSLIT
Radiacionno-konduktivnyj perenos tepla v sub- i sverhkriticheskih flyuidnyh sredah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 3-15. - DOI:
En
Combined Radiation-Conduction Heat Transfer in Sub- and Supercritical Fluid Media. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 3-15 (2007). https://doi.org/
Key words: supercritical fluids, processing of plant raw materials, lignin
Physical chemistry of polymers and thermodynamic compatibility of biopolymers theory are applied to the analysis of the behavior of the lignin-cellulose matrix of wood materials under the treatment in supercritical (SC) media. The most promising applications of SC fluid technologies in the area of chemical processing of wood and non-wood raw plant materials are discussed.
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7.0.100-2018
Prospects in Applying Supercritical Fluid Technologies to the Chemistry of Raw Plant Material / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 16-27. - DOI:
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Perspektivy primeneniya sverhkriticheskih flyuidnyh tekhnologij v himii rastitel'nogo syr'ya / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 16-27. - DOI:
En
Prospects in Applying Supercritical Fluid Technologies to the Chemistry of Raw Plant Material. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 16-27 (2007). https://doi.org/
Key words: phase behavior, critical point, multi-component phases, fiberoptic reflectometry, flow reactor
High precision two-channel fiberoptic reflectometer (OPR) has been developed for investigation of phase behavior of multi-component supercritical fluids in different areas of reactor. Phase behavior of binary mixtures СО2 + acetone, СО2 +methanol has been measured in a batch reactor in wide ranges of temperatures (20 ÷ 700°C) and pressures (50 ÷ 200 bar). The experimental data were compared with that calculated by Lorentz - Lorenz equation. Phase behavior of СО2 + acetophenone mixture in a flow capillary reactor has been investigated for different concentrations of acetophenone (7.5, 21.2, 34.1%). Our experiments with СО2 + methanol mixtures show the possibility to study phase behavior of multicomponent fluids in a flow supercritical fluid reactor filled with catalyst.
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7.0.100-2018
Two-channel Fiberoptic Reflectometry of Supercritical Media / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 28-39. - DOI:
TRANSLIT
/ – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 28-39. - DOI:
En
Two-channel Fiberoptic Reflectometry of Supercritical Media. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 28-39 (2007). https://doi.org/
Key words: high temperatures, high pressures, supercritical fluids, vibrational spectroscopy, UV-Vis absorption spectroscopy
Various experimental approaches and cells for spectroscopic studies at high temperatures and pressures (up to 500 °C and 1000÷1500 bar) are described. The cells for absorption spectroscopy cover a wide range of light radiation from mid IR to ultraviolet. The use of a simple Raman cell, either with microscope or directly in the sample compartment of a spectrometer, is discussed in detail. It is worth noticing that all designs under consideration provide high accuracy of quantitative measurements.
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7.0.100-2018
Spectroscopic Techniques for Studying Liquids and Supercritical Fluids at High Temperatures and Pressures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 40-52. - DOI:
TRANSLIT
Tekhnika spektral'nyh issledovanij zhidkostej i sverhkriticheskih flyuidov pri vysokih temperaturah i davleniyah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 40-52. - DOI:
En
Spectroscopic Techniques for Studying Liquids and Supercritical Fluids at High Temperatures and Pressures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 40-52 (2007). https://doi.org/
Key words: bioresorbable polymers, polymer microparticles, supercritical carbon dioxide, acoustic excitation
A new approach to control the process of «dry» (without any use of organic solvents) synthesis of bioresorbable polymer microparticles and porous fibers has been proposed and developed. It is based on the combination of treatment in supercritical fluids and intensive acoustic excitation. Low molecular weight (Mw ~ 1000) ε-polycaprolactone and D,L-polylactide microparticles and their agglomerates which can be used as a drug delivery vehicles were produced by spraying of the polymers plasticized in supercritical CO2 through the pulse nozzles. The significant lowering of the initial D,L-polylactide viscosity has been achieved by intensive acoustic agitation in supercritical fluid environment followed by the morphology changes of the final product. No noticeable alterations of both polymer molecular weight and polydispersity (Mw/Mn ratio) after the treatment were detected.
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ГОСТ
7.0.100-2018
Fabrication of Bioresorbable Polymer Microparticles with Supercritical Fluids / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 53-60. - DOI:
TRANSLIT
Poluchenie mikrochastic biorezorbiruemyh polimerov s pomoshch'yu sverhkriticheskih sred / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 53-60. - DOI:
En
Fabrication of Bioresorbable Polymer Microparticles with Supercritical Fluids. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 53-60 (2007). https://doi.org/
Key words: polymers, porosity, supercritical fluids, carbon dioxide
Methods of processing of bioresorbable polymers (polylactide and polylactide/ polyglycolide copolymers) in gas, liquid and supercritical media are studied. It is shown that processing of such polymers in supercritical medium results in high amounts of carbon dioxide absorbed in a polymer matrix. The following desorption of carbon dioxide leads to the creation of highly developed porosity (up to 2 cm3/g). The treatment of the polymers under study with liquid and gaseous carbon dioxide gives the total pore volume of 0.1 ÷ 0.3 cm3/g.
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7.0.100-2018
Formation of Porosity in Bioresorbable Polymers by their Treatment in Gaseous, Liquid and Supercritical Carbon Dioxide / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 61-68. - DOI:
TRANSLIT
Poluchenie poristyh biorezorbiruemyh polimerov obrabotkoj dioksidom ugleroda v gazoobraznom, zhidkom i sverhkriticheskom sostoyaniyah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 61-68. - DOI:
En
Formation of Porosity in Bioresorbable Polymers by their Treatment in Gaseous, Liquid and Supercritical Carbon Dioxide. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 61-68 (2007). https://doi.org/
Key words: radiation-conduction heat transfer, critical point, supercritical fluid
The results of experimental study of the parameter χ = (λeff/λcond) about a critical point of n-hexane are presented. The measurements are made using the flat layer method with interference visualization. A crucial decrease in the fraction of radiation heat transfer is established as temperature is approaching the critical point from both liquid and supercritical fluid state sides.
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ГОСТ
7.0.100-2018
Radiation-Conduction Heat Transfer about a Critical Point of n-Hexane / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 69-77. - DOI:
TRANSLIT
Radiacionno-konduktivnyj perenos tepla vblizi kriticheskoj tochki n-geksana / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 69-77. - DOI:
En
Radiation-Conduction Heat Transfer about a Critical Point of n-Hexane. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 69-77 (2007). https://doi.org/
Key words: supercritical fluid impregnation, spiroantroxazin, thermoplastic polymers
The impregnation of several thermoplastic polymers (polyethylene, polypropylene, polymethylmethacrylate, polycarbonate) with spiroxazin photochrome (SAO) having a stable unexcited form A, and photoexcited (colored) form B, was performed in supercritical CO2. It is found that, unlike other polimers under study, the supercritical fluid impregnation of polycarbonate (PC) with SAO causes the dramatic stabilization of its colored form B. The bleaching time of SAO in PC after its photoexcitation (900 c) is two orders of magnitude higher than that in polypropylene. Moreover, after supercritical fluid impregnation of PC up to 20 % of SAO is originally formed in colored form, which is not bleachable for 90 days (the whole period of observation), i.e. is extremely stable. The temperature and pressure effects on SAO concentration in different polymer matrixes were measured. At least some part of SAO incorporated into the polymeric matrix forms nanocrystals of ~ 10 ÷ 20 nm size. Possible mechanisms of the observed effect of the colored SAO form stabilization in the polycarbonate matrix are discussed.
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ГОСТ
7.0.100-2018
Effect of Stabilization of Colored Form of Spiroxazin Photochrome in Polycarbonate Matrix / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 1. – С. 78-85. - DOI:
TRANSLIT
Effekt stabilizacii okrashennoj formy fotohroma spirooksizinovogo ryada v matrice polikarbonata / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 1. – S. 78-85. - DOI:
En
Effect of Stabilization of Colored Form of Spiroxazin Photochrome in Polycarbonate Matrix. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 1, 78-85 (2007). https://doi.org/
Key words: supercritical state, structure of water, pair correlation functions
A new approach to the problem of the structure of liquid and supercritical water has been suggested that is based on the idea of preferential variations of the nearest ordering. The transition of water into the supercritical state is described in the terms of this conception. Analysis of some experimental data allowed us to show that the infinite cluster of H-bonded water molecules ceased to exist in the vicinity of critical isotherm. The phenomena associated with the surmounting of the percolation threshold may be important for the development of new supercritical technologies.
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7.0.100-2018
Water in the Supercritical State / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 2. – С. 5-19. - DOI:
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Sverhkriticheskoe sostoyanie vody / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 2. – S. 5-19. - DOI:
En
Water in the Supercritical State. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 5-19 (2007). https://doi.org/
Key words: aqueous solutions; critical point; equation of state; Krichevskii parameter; partial molar volume; supercritical water; water
The results of the study of thermodynamic properties of infinite dilution aqueous solutions (IDS) near the critical point (CP) of pure water using the Krichevskii parameter and the properties of water are reported. The values of the Krichevskii parameter for aqueous hydrocarbon, alcohol, salt, and gas have been calculated by using the available critical lines and phase diagrams data. The derived values of the Krichevskii parameter have been used to study thermodynamic and structural properties of the IDS in the critical and supercritical regions.
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7.0.100-2018
Krichevskii Parameter and Thermodynamic Properties of Infinitely Diluted Aqueous Solutions in the Proximity of the Water Critical Point / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 2. – С. 20-54. - DOI:
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Parametr Krichevskogo i termodinamicheskie svojstva beskonechno razbavlennyh vodnyh rastvorov vblizi kriticheskoj tochki vody / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 2. – S. 20-54. - DOI:
En
Krichevskii Parameter and Thermodynamic Properties of Infinitely Diluted Aqueous Solutions in the Proximity of the Water Critical Point. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 20-54 (2007). https://doi.org/
Key words: supercritical water, computer modeling, hydrogen bond
The interaction potential that includes non-electrostatic constituent of hydrogen bond is adopted for the modeling of water state in sub- and supercritical conditions. Molecular dynamic approach is used to calculate radial distribution functions, intrinsic energy, topology of the hydrogen bond network and its temporal behavior in different points of the supercritical region of the phase diagram. Effects of parameters of state (temperature, pressure, density) upon the structural and dynamic properties of water are analyzed.
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ГОСТ
7.0.100-2018
Effect of Parameters of State upon the Properties of Supercritical Water. Computer Modeling of the Structure and Dynamics of Hydrogen Bond Network / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 2. – С. 55-69. - DOI:
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Vliyanie parametrov sostoyaniya na svojstva sverhkriticheskoj vody. Komp'yuternoe modelirovanie struktury i dinamiki setki vodorodnyh svyazej / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 2. – S. 55-69. - DOI:
En
Effect of Parameters of State upon the Properties of Supercritical Water. Computer Modeling of the Structure and Dynamics of Hydrogen Bond Network. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 55-69 (2007). https://doi.org/
Key words: molecular dynamics, supercritical conditions, computer simulation, structural and dynamic characteristics, water solutions of methanol
The analysis of structural and dynamic characteristics of methanol - water mixtures with the method of molecular dynamics was performed for sub- and supercritical parameters. The range of concentrations of methanol in water, corresponding to the maximum of a heat capacity of these mixtures under normal conditions were investigated. It was revealed that water structure is totally destroyed in supercritical solutions methanol - water at the range of concentrations different from the maximum of its heat capacity. However, certain stabilization of water was observed in the region corresponding to this maximum.
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7.0.100-2018
The Structure and Dynamics of Solvent in Water Solution of Methanol under Supercritical Conditions / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 2. – С. 70-77. - DOI:
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Struktura i dinamika rastvoritelya v vodnom rastvore metanola pri sverhkriticheskih usloviyah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 2. – S. 70-77. - DOI:
En
The Structure and Dynamics of Solvent in Water Solution of Methanol under Supercritical Conditions. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 70-77 (2007). https://doi.org/
Key words: water-salt systems, supercritical fluids, immiscibility of liquid phases, salt solubility, phase diagrams
General features of the phase behavior of systems "water-salt" of different types in sub- and supercritical conditions are analyzed. Type 1 systems are characterized by the increasing solubility of non-volatile component (salt) at rising temperature, whereas in type 2 systems the solubility decreases. An existence of homogeneous unsaturated fluid and of fluid equilibrium with solid salt components at temperatures above the critical temperature of water at any pressures is a distinguishing feature of water-salt systems of type 2. An appearance of supercritical fluid in the systems of type 1 is observed only above the critical temperature of salt. Review of available experimental data permits to establish both the general features of salt solubility behavior in binary systems of various types and some distinctive properties of hydrothermal solubility of the salts of type 2 in aqueous solutions of type 1 salts. Special attention is paid to the processes of heterogenization of supercritical fluid saturated with the salts of type 2 when the salt of type 1 is added and to an influence of immiscibility phenomena, which are common in the hydrothermal salt solutions on fluid phase heterogenization.
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7.0.100-2018
Special Features of Salts of Type 2 Solubilities in Binary and Ternary Water-Salt Systems at Elevated Temperatures and Pressures / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 2. – С. 78-96. - DOI:
TRANSLIT
Osobennosti rastvorimosti solej 2 tipa v dvuh- i trekhkomponentnyh vodno-solevyh sistemah pri povyshennyh temperaturah i davleniyah / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 2. – S. 78-96. - DOI:
En
Special Features of Salts of Type 2 Solubilities in Binary and Ternary Water-Salt Systems at Elevated Temperatures and Pressures. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 2, 78-96 (2007). https://doi.org/
Key words: supercritical and liquid carbon dioxide, organic ligands, radionuclides, actinides, actinide oxides, radionuclide extraction, spent nuclear fuel
The developments in supercritical fluid extraction (SFE) of radionuclides progressed since 1990's are reviewed. The possibility of extraction of radionuclides using supercritical and liquid carbon dioxide (SC- and L-CO2) containing different organic ligands from solutions, different matrixes as well as from mixtures of metal oxides was stated. Perspectives of SFE utilization for the reprocessing of spent nuclear fuel (SNF) are discussed. The latter is very promising as a possibility to diminish the production of highly radioactive aqueous and organic solutions, which are formed as by-products in existing technologies of SNF reprocessing.
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7.0.100-2018
Supercritical Fluid Extraction of Radionuclides / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 3. – С. 5-24. - DOI:
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Sverhkriticheskaya flyuidnaya ekstrakciya radionuklidov / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 3. – S. 5-24. - DOI:
En
Supercritical Fluid Extraction of Radionuclides. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 5-24 (2007). https://doi.org/
Key words: supercritical and liquid carbon dioxide, actinides, fission products, actinide oxides, organic ligands, radionuclide extraction, spent nuclear fuel reprocessing, countercurrent chromatography
The main regularities of actinide recovery from oxide mixtures by supercritical carbon dioxide CO2 (SC-CO2) containing adduct of tri-n-butylphosphate (TBP) and other organic ligands with HNO3 are studied. It was found that effective actinide extraction by such adducts can be achieved even in the absence of SC-CO2. The extraction of Uranium and main fission products (FP) from model spent nuclear fuel (MSNF) was investigated. It was shown that at >99 % of U extraction the principal fractions of 95Zr и 95Nb (up to 90 %) transferred into adduct phase, as well as 131I and partially 103Ru (~30 %), 99Tc (20 %) and lanthanides (Ln) (up to 10 %). A complete separation of U from 137Cs, 85Sr, 140Ba, as well as from the main part of 140La, 141-144Ce and 147Nd can be achieved. Uranium separation from the remaining part of FP is completed by the adduct dissolution in liquid CO2, transfer of the obtained solution to the separation column of planetary centrifuge, and its further processing by countercurrent chromatography (CCC) in dynamic mode.
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7.0.100-2018
Use of Supercritical and Liquid Carbon Dioxide for Actinide Extraction from Dioxides by Adducts of Organic Ligands with HNO3 and their Separation by Liquid Countercurrent Chromatography / – Текст : непосредственный // Сверхкритические Флюиды: Теория и Практика.. – 2007. – Т. 2. – № 3. – С. 25-39. - DOI:
TRANSLIT
Ispol'zovanie sverhkriticheskogo i zhidkogo dioksida ugleroda dlya ekstragirovaniya aktinoidov iz dioksidov adduktami organicheskih ligandov s HNO3 i ih razdeleniya zhidkostnoj hromatografiej so svobodnoj nepodvizhnoj fazoj / – Sverhkriticheskie Flyuidy: Teoriya i Praktika.. – 2007. – Т. 2. – № 3. – S. 25-39. - DOI:
En
Use of Supercritical and Liquid Carbon Dioxide for Actinide Extraction from Dioxides by Adducts of Organic Ligands with HNO3 and their Separation by Liquid Countercurrent Chromatography. Sverhkriticheskie Flyuidy: Teoriya i Praktika, 3, 25-39 (2007). https://doi.org/