• Title/Summary/Keyword: High-pressure phase equilibria

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Lattice-Fluid Description of Phase Equilibria in Supercritical Fluids (격자유체이론을 이용한 초임계유체내에서의 상평형)

  • Kim, Ki-Chang
    • Journal of Industrial Technology
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    • v.11
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    • pp.3-16
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    • 1991
  • The lattice-fluid theory are adopted for modeling the phese equilibria in supercritical fluids, In order to investigate effects of the nonrandom distribution of holes in mixtures on the phase equilibria, the equation of state and the chemical potential of the binary miture are formulated with taking into account nonrandomness of holes distributions in the fluid mixture. The relations of phase equilibria formulated in this work are tested through predictions of solubility of heavy solids in supercritical fluids and predictions of high pressure phase equilibria of binary mixtures. Results obtained exhibit that the lattice fluid model with assumptions of nonrandomness of hole distributions is successful in quantatively mideling the phase equilibria of mixtures of molecules of dissimilar sizes, specifically solids-supercritical fluid mixtures.

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Carbon Dioxide-Isopropyl Alcohol System: High Pressure Phase Behavior and Application with SAFT Equation of State (이산화탄소-이소프로필 알코올계: 고압 상거동 및 SAFT 상태방정식 적용)

  • Kwak, Chul;Byun, Hun-Soo
    • Applied Chemistry for Engineering
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    • v.10 no.2
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    • pp.324-329
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    • 1999
  • In this work, high pressure binary phase equilibria data of carbon dioxide and isopropyl alcohol were obtained by experiment. A static type experimental apparatus was made to measure temperature, pressure and phase equilibria composition. The experimental apparatus was tested by comparing the measured phase equilibria data of the carbon dioxide-isopropyl alcohol system at $80^{\circ}C$ with those of Rodosz. The binary phase behavior data of carbon dioxide-isopropyl alcohol system were measured in range of 41 to 133 bar and at temperatures of 40, 60, 80, 100 and $120^{\circ}C$. The solubility of isopropyl alcohol increases as the temperatures increases at constant pressure. Also, these carbon dioxide-alcohol solute system have critical-mixture curves that exhibit maxima in pressure at temperatures between the critical temperatures of carbon dioxide and isopropyl alcohol. The experimental data obtained in this study were modeled using the statistical associating fluid theory(SAFT) equation of state. A good fit of the data was obtained with SAFT using two adjustable parameters for the carbon dioxide-isopropyl alcohol system.

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Solid-liquid phase equilibria on the GdBa2Cu3O7-δ stability phase diagram in low oxygen pressures (1 - 100 mTorr)

  • Lee, J.W.;Lee, J.H.;Moon, S.H.;Yoo, S.I.
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.4
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    • pp.28-31
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    • 2012
  • We report the solid-liquid phase equilibria on the $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) stability phase diagram in low oxygen pressures ($PO_2$) ranging from 1 to 100 mTorr. On the basis of the GdBCO stability phase diagram experimentally determined in low oxygen pressures, the isothermal sections of three different phase fields on log $PO_2$ vs. 1/T diagram were schematically constructed within the $Gd_2O_3-Ba_2CuO_y-Cu_2O$ ternary system, and the solid-liquid phase equilibria in each phase field were described. The invariant points on the phase boundaries include the following three reactions; a pseudobinary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3$ + liquid ($L_1$), a ternary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3+GdBa_6Cu_3O_y$ + liquid ($L_2$), and a monotectic reaction of $L_1{\leftrightarrow}GdBa_6Cu_3O_y+L_2$. A conspicuous feature of the solid-liquid phase equilibria in low $PO_2$ regime (1 - 100 mTorr) is that the GdBCO phase is decomposed into $Gd_2O_3+L_1$ or $Gd_2O_3+GdBa_6Cu_3O_y+L_2$ rather than $Gd_2BaCuO_5+L$ well-known in high $PO_2$ like air.

A Study on Phase Behavior of CO2-Acetonitrile and CO2-Acrylonitrile System at High Pressure (고압에서 CO2-아세토니트릴과 CO2-아크릴로니트릴계에 대한 상거동에 관한 연구)

  • Byun, Hun-Soo;Kim, Youn-Sop;Im, Jong-Kyun
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.924-929
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    • 1998
  • In this work, high pressure binary phase equilibria data of carbon dioxide with acetonitrile and acrylonitrile were obtained experimentally. A new static type experimental apparatus was built to measure temperature, pressure and phase equilibria composition. The accuracy of the experimental apparatus was tested by comparing the measured phase equilibria data of the carbon dioxide-acetonitrile system at $75^{\circ}C$ with those of McHugh and coworkers. The binary phase behavior data of carbon dioxide-acetonitirle system were measured from 2.4 to 14.5 MPa at $55^{\circ}C$, $75^{\circ}C$ and $100^{\circ}C$. Also, the phase equilibria of the system carbon dioxide-acrylonitrile were measured from 1.6 MPa up to 13.9 MPa at $45^{\circ}C$, $65^{\circ}C$, $85^{\circ}C$ and $105^{\circ}C$. The solubility of acetonitrile and acrylonitrile increases as the temperatures increases at constant pressure. Also, these two carbon dioxide-polar solute system have continuous critical-mixture curves that exhibit maximums in pressure at temperatures between the critical temperatures of carbon dioxide and acetonitrile or acrylonitrile. The experimental data obtained in this study were modeled using the Peng-Robinson equation of state. Good agreement between calculated and experimental results was observed.

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Phase Equilibrium of Binary Mixture for the (Carbon Dioxide + 1-Phenyl-2-Pyrrolidone) System at High Pressure

  • Lee, Ho;Jeong, Jong-Dae;Byun, Hun-Soo
    • Korean Chemical Engineering Research
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    • v.56 no.5
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    • pp.732-737
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    • 2018
  • Experimental data of phase equilibria are reported for the binary mixture of 1-phenyl-2-pyrrolidone in supercritical carbon dioxide. Phase behavior data was measured in a synthetic method at a temperature ranging from 333.2 to 393.2 K and at pressures up to 97.14 MPa. The solubility of 1-phenyl-2-pyrrolidone in the carbon dioxide + 1-phenyl-2-pyrrolidone system increased as temperature increased at a constant pressure and it exhibited the type-I phase behavior. The experimental data for the binary mixture were correlated with the Peng-Robinson equation of state using mixing rule and the critical properties of 1-phenyl-2-pyrrolidone were predicted with the Joback and Lyderson method.

An Experimental Study on Vapor-Liquid Equilibria of $CO_2$/Oil Mixtures in the Range of Evaporator Working Pressure (증발기 작동 압력 범위에서 $CO_2$/오일 혼합물의 기상-액상 평형 실험)

  • Lee, Chi-Seok;Lee, Kyoung-Youl;Kang, Byung-Ha;Park, Kyoung-Kuhn
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.380-385
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    • 2005
  • An experimental apparatus was constructed to obtain vapor-liquid equilibrium data for $CO_2$/oil mixtures using mass analysis method with sample cylinder. Lubricants employed were POE(Polyol Ester) oil and PAG(Poly Alkylene Glycol) oil. The phase equilibria of $CO_2$/oil mixtures formed in high pressure equilibrium cell are observed through sight glasses at the opposite ends. Data were measured over the temperature range from -10 to $10^{\circ}C$ with $5^{\circ}C$ intervals under pressures up to 14 MPa. Mole fractions were calculated for $CO_2$/oil and $CO_2$/PAAG, respectively and were compared with each other.

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Phase equilibria and structure identification of tert-butylhydroperoxide + gaseous clathrate hydrates (이성분계(3차 부틸-히드로과산화물 + 기체) 클러스레이트 하이드레이트의 구조적 특성과 열역학적 안정성에 관한 연구)

  • Youn, Yeobeom;Cha, Minjun;Kwon, Minchul;Lee, Huen
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.150.1-150.1
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    • 2011
  • Structure-II hydrate has been highlighted due to its higher gas storage capacity and favorable thermodynamic conditions. In this study, we introduce a new structure-II hydrate former, tert-butyl hydroperoxide (TBHP) and confirm the structural characteristics through High-Resolution Powder Diffraction (HRPD), $^{13}C$ solide-state NMR and Ramanspectroscopy. Here,we also investigated the thermodynamic stability of binary(TBHP+gaseous) clathrate hydrates. The experimental data were generated using an isochoric pressure-search method. The dissociation data for (TBHP +gaseous) clathrate hydrates are compared with the other hydrocarbon hydrate and pure gaseous hydrate.

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High Pressure Binary Phase Equilibria Measurements of α-Tetralol with Carbon Dioxide (이산화탄소와 α-Tetralol과의 2성분계 고압상평형 측정)

  • Byun, Hun-Soo;Kim, Choon-Ho;Hwang, Young-Gi;Kwak, Chul
    • Applied Chemistry for Engineering
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    • v.7 no.1
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    • pp.67-74
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    • 1996
  • The binary phase equilibrium experiments of carbon dioxide/1,2,3,4 ${\alpha}$-tetrahydro-1-naphthol(${\alpha}$-tetralol) system were conducted to get phase equilibrium and mixture density data at 313.2K, 343.2K and 373.2K and within pressure ranges of 6.0 MPa to 35.0MPa. The phase equilibrium apparatus was type that circulated the vapor and liquid phase, the expended volume measuring system was adopted to microsampling technique for the analysis. The phase equilibrium and mixture density data were obtained for carbon dioxide/${\alpha}$-tetralol system from liquid and vapor phase. The mole fraction of carbon dioxide in liquid phase decreases and the mole fraction of ${\alpha}$-tetralol in vapor phase increases at constant pressure according to increment of temperature, and both the densities of the vapor and liquid phase approach to the mixture critical density as the pressure increases at any temperature. For she thermodynamic analysis, the experimental data were correlated with Peng-Robinson equation in cubic equation of state and compared to theoretical values of carbon dioxide/${\alpha}$-tetralol system. The AAD result was in the range of 1.08%~8.93% in the case of K(1), and was in the range of 45.71%~72.34% in the case of K(2).

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Phase Equilibria of Ionic Liquid/Organic Compound/Supercritical CO2 Systems (이온성액체/유기화합물/초임계이산화탄소계의 상평형)

  • Lim, Bang-Hyun;Kim, Jong-Won;Paek, Sang-Min;Son, Bo-Kook;Lee, Yong-Rok;Lee, Chul Soo;Lee, Huen;Ra, Chun-Sup;Shim, Jae-Jin
    • Clean Technology
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    • v.12 no.3
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    • pp.128-137
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    • 2006
  • The volume change of an ionic liquid and the phase separation behavior of room temperature ionic liquid(RTIL)/organic compound mixture in supercritical carbon dioxide were measured in a high pressure view cell. 1-Butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][$BF_4$]) was used as ionic liquid(IL). and methanol and dimethyl carbonate were used as organic compound. For a fixed amount of [bmim][$PF_6$] the lower critical endpoint (LCEP) pressure, where the liquid phase is split, decreased as increasing the amount of organic compound. The LCEP pressure became higher as the water content of ionic liquid was higher. However, for water contents above a certain value, no LCEP was formed. LCEP appeared 1.0 MPa higher for a mixture with [bmim][$BF_4$] than with [bmim][$PF_6$]. There was almost no difference in the K-point pressures for different types of ionic liquid and for different amounts of organic liquid. When the concentration of ionic liquid([bmim][$PF_6$]) (IL/(IL+MeOH)) in the initial liquid mixture was larger than 5.9 mol% at the LCEP of the mixture, the volume of $L_1$ because larger than the volume of $L_2$. When it was smaller, however, the volume became smaller, too. The volume change of ionic liquid in the presence of carbon dioxide decreased as increasing the temperature, while it increased as increasing the pressure. For temperatures between 313.15 to 343.15K at 300 bar, it was about 123~125 % of the original volume.

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Granulite-facies metamorphism and P-T evolutionary path of cordierite gneisses in the Cheongpyeong-Yangpyeong area (청평-양평 지역에 분포하는 근청석 편마암의 백립암상 변성작용과 P-T 진화 경로)

  • 조윤호;조문섭;이승렬
    • The Journal of the Petrological Society of Korea
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    • v.5 no.1
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    • pp.52-65
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    • 1996
  • Precambrian metamorphic rocks of the Cheongpyeong-Yangpyeong area, central Gyeonggi massif, comprise gneiss, schist, quartzite and amphibolite. Mineral, assemblages of pelitic gneisses are characterized by biotite + cordierite + garnet + sillimanite + K-feldspar + plagioclase + quartz together with minor muscovite, spinel and corundum, and represent the granulite facies metamorphism. In particular, kyanite occurs as fine-grained relict phase inside plagioclase of three gneiss samples. Metamorphic conditions are estimated from garnet-biotite and garnet-cordierite geothermometers in conjunction with garnet-$Al_2SiO_5$-quartz-plagioclase (GASP) and garnet-rutile-$Al_2SiO_5$-ilmenite (GRAIL) geobarometers. They are 700-$850^{\circ}C$ and 3.2-8.3 kbar, and 580-$690^{\circ}C$ and 2.1-3.2 kbar, respectively, when the core and rim compositions of garnet are use. Garnet of the GASP assemblage increases rimward in the Fe and Mn contents but decreases in the Mg content, whereas its Ca content does not vary significantly. Together with the occurrence of relict kyanite and the result of P-T estimates, compositional zoning patterns of garnet indicate a clockwise P-T history. Moreover, the preservation of high-pressure minerals such as kyanite in plagiocalse, even after the medium-pressure granulite facies metamorphis, suggests a rapid change in P-T conditions.

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