• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.150.1-150.1
• /
• 2010

가스 하이드레이트는 물분자와 저분자량의 가스분자가 고압과 저온에서 수소결합을 이루며 형성되는 결정성 화합물을 말한다. 최근 가스 하이드레이트의 물리적 특성과 형성 원리를 이용하여 다양한 분야로의 적용 연구가 수행되고 있는데 이의 효과적 달성을 위해서는 가스 하이드레이트의 상평형 연구가 필수적이다. 기존에 수행되는 상평형 실험 방법은 온도의 변화에 따라 하이드레이트를 해리시키고 압력의 변곡점을 찾는 것으로 최소 24시간이 소요되지만, 본 연구진이 제안하는 QCM을 이용한 방법은 1 ng의 무게에 1 Hz의 변화를 나타내는 수정진동자의 민감성을 이용한 것으로 약 2~3시간 내에 상평형 실험을 수행할 수 있고, 하이드레이트의 기억효과(Memory Effect)를 이용하여 연속적인 상평형 실험도 가능하다. 본 연구에서는 QCM 반응기의 원리 및 실험 방법에 대하여 설명하고 열역학적 촉진제를 첨가한 상평형 실험결과를 제시함으로써 상대적으로 저렴한 가격으로 다양한 촉진제와 억제제 첨가 시 나타나는 상평형 효과를 빠른 시간 내에 선별할 수 있는 방법으로 QCM을 이용한 방법을 제안하고자 한다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.2 no.3
• /
• pp.90-98
• /
• 1998

The vaporization process of liquid oxygen(LOX) at high pressure environment is numerically investigated. The present vaporization model can account for the high-pressure effects such as ambient gas solubility, real gas behavior and variable properties. The predicted phase-equilibrium compositions for $N_2$/$H_2$ and $O_2$/He system are well agreed with experimental data. The LOX vaporization characteristics is parametrically studied for wide range of the operating conditions encountered in the high-pressure combustion process of liquid rocket engine.

• Applied Chemistry for Engineering
• /
• v.7 no.1
• /
• pp.67-74
• /
• 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).

• Clean Technology
• /
• v.17 no.1
• /
• pp.19-24
• /
• 2011

The bubble point pressures of binary mixtures of carbon dioxide ($CO_2$) and N,N-dimethylformamide (DMF) were measured by using a high-pressure experimental apparatus equipped with a variable-volume view cell, at various $CO_2$ compositions in the range of temperatures above the critical temperature of $CO_2$ and below the critical temperature of DMF. The experimental bubble point pressure data were correlated with the Peng-Robinson equation of state (PR-EOS) to estimate the corresponding dew point compositions at equilibrium with the bubble point compositions. The experimentally measured bubble point pressures gave good agreement with those calculated by the PR-EOS. The variable-volume view cell equipment was verified to be an easy and quick way to measure the bubble point pressures of high-pressure compressible fluid mixtures.

• Applied Chemistry for Engineering
• /
• v.20 no.1
• /
• pp.94-98
• /
• 2009

The bubble point pressures of dimethyl carbonate and carbon dioxide mixtures were measured by using a high-pressure experimental apparatus equipped with a variable-volume view cell, at various $CO_2$ compositions in the range of temperatures above the critical temperature of $CO_2$ and below the critical temperature of dimethyl carbonate. The experimental bubble point pressure data were correlated with the Peng-Robinson equation of state (PR-EOS) to estimate the corresponding dew point compositions at equilibrium with the bubble point compositions. The experimentally measured bubble point pressures gave good agreement with those calculated by the PR-EOS. The variable-volume view cell equipment was verified to be an easy and quick way to measure the bubble point pressures of high-pressure compressible fluid mixtures.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.8
• /
• pp.1121-1131
• /
• 1998

The present study is numerically investigated for the high-pressure effects on the vaporization process in the convection-dominating flow field. Numerical results agree well with the available experimental data. The fuel droplet vaporization characterization is parametrically studied for the wide range of the operating conditions encountered with the high-pressure combustion process of turbocharged diesel engines.

• Clean Technology
• /
• v.19 no.1
• /
• pp.8-12
• /
• 2013

Phase behavior of carbon dioxide + surfactant binary system and carbon dioxide + surfactant + water ternary system was investigated at the temperatures from 318 K to 348 K by using high pressure vapor liquid equilibrium apparatus containing variable-volume view cell. Sorbitan monopalmitate was used as the surfactant. The cloud point pressures for the binary mixture of carbon dioxide + sorbitan monopalmitate increased with an increasing of system temperatures and the maximum cloud point pressure was observed at the composition of 0.226 wt% of sorbitan monopalmitate. On the other hand, as the temperatures and compositions of water increased, the cloud point pressures for ternary system containing 0.1 wt% of sorbitan monopalmitate increased significantly. For the ternary system of constant 0.2 wt% of water, the cloud point pressure curves show relatively flat according to the change of compositions of surfactant. The cloud point pressures increased when the temperatures and compositions of water increased.

• Analytical Science and Technology
• /
• v.24 no.6
• /
• pp.467-476
• /
• 2011

Solubility data of carbon dioxide ($CO_2$) in the imidazolium-based ionic liquids with methylsulfate anion are presented at pressures up to about 45 MPa and at temperatures between 303.15 K and 343.15 K. The ionic liquids studied in this work were 1-ethyl-3-methylimidazolium methylsulfate ([emim][$mSO_4$]), 1-butyl-3-methylimidazolium methylsulfate ([bmim][$mSO_4$]). The solubilities of $CO_2$ were determined by measuring the bubble point or cloud point pressures of the binary mixtures using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. The equilibrium pressure increased very steeply at high $CO_2$ compositions. The $CO_2$ solubility in ionic liquids increased with increase of the total length of alkyl chains attached to the imidazolium cation of the ionic liquids. The phase equilibrium data for the $CO_2$ + ionic liquid systems have been correlated using the Peng-Robinson equation of state.

• Korean Chemical Engineering Research
• /
• v.48 no.6
• /
• pp.763-767
• /
• 2010

High-pressure phase behavior for the binary mixture of 1-propanol with supercritical $CO_2$ has been measured by means of a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The equilibrium loci of the pressure - composition and pressure - temperature were obtained for the binary mixture of 1-propanol + $CO_2$ system at 305.15 K, 313.15 K, 323.15 K and 333.15 K, and from 2 MPa to 11 MPa. The critical temperature of the mixture increased with the temperature. The pressure-composition line for the binary mixture of $CO_2$-1-propanol system showed a typical type-II phase behavior. The experimental P-x envelopes were correlated by using the Peng-Robinson equation of state in a satisfactory manner to obtain the parameters with $k_{ij}=0.116$ and ${\eta}_{ij}=-0.065$.

• 한국연소학회:학술대회논문집
• /
• 2001.06a
• /
• pp.106-118
• /
• 2001

A rigorous study of single droplet vaporization under quiescent high pressure atmosphere is attempted adopting method of flash evaporation calculation for vapor-liquid equilibrium. Results due to flash method shows excellent agreement with measurement. Also shown is the present model fairly capable of depicting transients of droplet vaporization under high pressure environment, such as ambient gas solubility, property variation, and multicomponent transports. Systematic treatment of these effects with emphasis on vapor-liquid phase equilibrium revealed; conventional treatment for subcritical droplet vaporization, such as $d^2$-law, leads to erroneous prediction of droplet history, augmented gas solubility is significant under supercritical pressure, and vaporization rate proportionally increase with pressure.