• 대한화학회지
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• 제31권6호
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• pp.481-485
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• 1987

확장된 Flory-Huggins의 격자이론에 의해 예측될 수 있는 액체 이성분계의 여러 부분혼화도를 제시하였으며, 각 경우에 있어서의 수학적 조건를 구하였다. 그리고, 그 이론을 사용하여 물-2-부탄올계에서 나타나는 비정상적인 부분혼화도가 존재할 수 있음을 보였다.

• 대한화학회지
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• 제14권2호
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• pp.193-199
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• 1970

Further validity of the significant structure theory has been tested by calculating the viscosities of binary mixtures-three pairs of $C_6H_6(1)+C_6H_{12}\;(2),\;CCI_4\;(1)+C_6H_6{2}and\l;CCI_4(1)+C_6H_{12}(2)$-and also by calculating the viscosities of n-$C_5H_{12}\;and\;n-C_6H_{14}$ in the pressure range of 1 bar to 4000 bars. The results are quite satisfactory for both cases and provide another evidence for the validity of the significan structure theory.

• 에너지공학
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• 제25권4호
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• pp.190-197
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• 2016

인화점은 가연성 액체 용액을 안전하게 취급하기 위한 중요한 성질 중 하나이다. 본 논문에서는 Seta flash 밀폐식 장치를 이용하여 이성분계 용액인 water+1-propanol과 water+2-propanol계의 인화점을 측정하였다. 회귀 분석법을 이용하여 인화점을 계산하였다. 또한 라울의 법칙을 이용하여 인화점을 계산하였고, van Laar 식의 이성분계 파라미터를 최적화시키는 방법을 통해 인화점을 예측하였다. 각 인화점 계산 결과와 측정 결과를 비교하였다. 그 결과, 회귀 분석법에 의한 인화점 계산치가 가장 측정치를 잘 모사하였다.

• 한국안전학회지
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• 제32권6호
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• pp.34-39
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• 2017

Vapor-liquid equilibrium calculation is required to properly design and operation of distillation process. The general calculation method is to use binary interaction parameter. Lower flash points of cyclohexanol+aniline and cyclohexanol+cyclohexanone were measured by using Seta-flash closed cup apparatus. The measured flash points were compared with those calculated by the method based on Raoult's law and the optimization method using Wilson equation. The absolute average errors(A.A.E.) of the results calculated by Raout's law are $0.25^{\circ}C$ and $1.07^{\circ}C$ for cyclohexanol+aniline and cyclohexanol+cyclohexanone, respectively. The absolute average errors of the results calculated by the optimization method are $0.22^{\circ}C$ and $0.65^{\circ}C$ for cyclohexanol+aniline and cyclohexanol+cyclohexanone, respectively. As can be seen from A.A.E., the calculated values based on the optimization method were found to be better than those based on the Raoult's law. The binary interaction parameters calculated by the optimization method are used to predict the dew points of cyclohexanol+aniline and cyclohexanol+cyclohexanone. The A.A.E. for these mixtures show that there is an acceptable agreement between experimental and calculated dew poins.

• 한국응용과학기술학회지
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• 제17권2호
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• pp.132-138
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• 2000

Excess enthalpies ($H^{E}$) were measured by isothermal flow calorimetry for the nonionic amphiphile 2-butoxyethanol/water mixtures at 10 different temperatures (48.5 to $70^{\circ}C$) around and above the lower consolute solution temperature, $T_{lc}$. $H^{E}$ exhibits U-shape for the binary mixtures, and is large and negative which reflects substantial interaction between two chemical species. When the commonly used, semi-empirical Redlich-Kister (RK) polynomials were fitted to the measured $H^{E}$, plots of $H^{E}$ vs. weight fraction provided more accurate fitting with fewer parameters than conventionally drawn $H^{E}$ vs. mole fraction plots. This was due to the enhanced symmetry of $H^{E}$ vs. weight fraction plots. Using the fitted Redlich-Kister polynomials and the Gibbs-Helmholtz relation, temperature dependence of the activity coefficients were found and compared to the values determined from vapor-liquid equilibria. The activity coefficients were in the range of one to three, indicating that the binary system deviates from ideality but not substantially. They slightly depended on temperature and the temperature effect was equivalent to 10 % change in the activity coefficients.

• 대한기계학회논문집B
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• 제22권4호
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• pp.440-451
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• 1998

An experimental study has been conducted to investigate solidification of NH$_{4}$CI-H$_{2}$0 mixtures inside a vertical rectangular enclosure. Solidification process is visualized by the shadowgraph method. Emphasis is placed on the effect of solidification parameters such as the aspect ratio, cooling wall temperature and initial composition. The aspect ratio shows a dominant effect on the number and developing time of the double diffusive layers which reveals the relative strength of solutal convection to thermal convection. Similar flow pattern is observed when the concentration difference between interdendritic liquid and the pure liquid which drives solutal convection is the same regardless of the different cooling wall temperature and initial concentration.

• 한국산학기술학회논문지
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• 제13권2호
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• pp.906-918
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• 2012

본 연구에서는 천연가스 및 냉매를 구성하고 있는 성분들에 대한 증기압, 증발잠열, 액상의 밀도 및 이성분계 기액 상평형을 추산하는데 있어서 GERG-2004 모델식과 Peng-Robinson(PR) 상태방정식을 서로 비교하였다. 비교결과 GERG-2004모델식은 액상의 밀도 추산에 있어서 PR 상태방정식에 비해 정확성이 높았으나, 기액 상평형 추산에 대한 정확성은 오히려 낮았다. 한편, PR 상태방정식에서 Costald 상관 관계식을 사용하여 액상의 밀도를 추산한 경우에는 실험값과 오차율이 1% 이내로써 GERG-2004 모델식을 사용한 추산 결과와 거의 차이가 없었으며, 증기압과 증발 잠열의 추산은 GERG-2004모델식과 PR 상태방정식이 거의 유사한 결과를 나타냄을 알 수 있었다.

• Macromolecular Research
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• 제12권2호
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• pp.246-250
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• 2004

We have classified a number of aqueous ternary systems containing two different polymers into three types by focusing on the deviation of the Huggins constant k'from the additivity line. Systems of type I have negative deviations of k'; the repulsive interaction between the two different polymers dominates. In systems of type II, k' almost follows the additivity relation; the repulsive and attractive interactions between the two different polymers are balancing. Type III systems have positive deviations of k'; the attractive interactions are relatively dominant. This classification of systems is supported by the fact that the positive and negative deviations of k' from the additivity line also correspond to the sign of interaction parameter between polymer 2 and 3, Δb$\_$23/. Furthermore, we have verified the relatively high compatibility between dextran and poly(vinyl alcohol) by determining the binodal concentration of a liquid-liquid phase separation for a water/dextran/poly(vinyl alcohol) system, which is classified as type III. Thus, we found that the compositional dependence of k' closely relates to the compatibility of binary polymer mixtures in aqueous ternary systems.

• 청정기술
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• 제25권2호
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• pp.140-146
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• 2019

산업현장에서 액체의 화재 및 폭발 위험을 결정하는데 사용되는 가장 중요한 변수 중 하나인 인화점은 가연 물질에 대한 화재 위험성을 나타내는 지표이며 위험물의 안전성 평가를 위한 중요한 정보로 활용된다. 본 연구의 목적은 석유 화학 공정에서 아주 중요한 용매로 사용되는 알킬 알코올과 함께 파라핀계 탄화수소의 대표적인 화합물인 2,2,4-trimethylpentane을 포함하는 이성분 혼합물인 {ethanol + 2,2,4-trimethylpentane}, {1-propanol + 2,2,4-trimethylpentane} 그리고 {2-propanol + 2,2,4-trimethylpentane} 계에 대한 인화점을 Stanhope-Seta 밀폐식 인화점 측정기를 이용하여 측정하였다. 각 이성분계 혼합물에 대한 인화점을 예측하기 위해 Raoult's의 법칙, Wilson, NRTL 그리고 UNIQUAC 파라미터를 이용하였고 실험 결과와 비교해 보았다. 비교 결과 Raoult's의 법칙을 제외하고 모든 실험값과 예측값과 실험값은 최대 편차가 1.28 K이내의 결과로 유사함을 보였다. 또한 측정된 모든 계에서 최소인화점은 발견되지 않았다.

• Journal of Mechanical Science and Technology
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• 제20권3호
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• pp.399-408
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• 2006

Nucleate pool boiling heat transfer coefficient (HTCs) were measured with one nonazeotropic mixture of propane/isobutane and two azeotropic mixtures of HFC134a/isobutane and propane/HFC 134a. All data were taken at the liquid pool temperature of $7^{\circ}C$ on a horizontal plain tube of 19.0mm outside diameter with heat fluxes of $10\;kW/m^2\;to\;80kW/m^2$ with an interval of $10\;kW/m^2$ in the decreasing order of heat flux. The measurements were made through electrical heating by a cartridge heater. The nonazeotropic mixture of propane/isobutane showed a reduction of HTCs as much as 41% from the ideal values. The azeotropic mixtures of HFC134a/isobutane and propane/HFC134a showed a reduction of HTCs as much as 44% from the ideal values at compositions other than azeotropic compositions. At azeotropic compositions, however, the HTCs were even higher than the ideal values due to the increase in the vapor pressure. For all mixtures, the reduction in heat transfer was greater with larger gliding temperature difference. Stephan and Korner's and lung et al's correlations predicted the HTCs of mixtures with a mean deviation of 11%. The largest mean deviation occurred at the azeotropic compositions of HFC134a/isobutane and propane/HFC134a.