• Fire Science and Engineering
• /
• v.27 no.5
• /
• pp.70-74
• /
• 2013

The flash point is one of the most important physical properties to charaterize fire and explosion hazard of liquid solutions. The maximum flash point of liquid mixture is larger than those of the individual components. In this study, the flash points of 2-pentanol+acetic acid system were measured by Seta flash closed cup tester. This system exhibited the maximum flash point behavior. The flash points were estimated by the Raoult's law and the optimization methods using the van Laar and Wilson equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• Fire Science and Engineering
• /
• v.29 no.6
• /
• pp.45-50
• /
• 2015

The flash point is one of the most important properties for characterizing the fire and explosion hazard of liquid solutions. In this study, a Tag open-cup apparatus was used to measure the flash points of two flammable binary mixtures, n-decane + n-octanol and acetic acid + n-butanol. The flash point temperature was estimated using the UNIFAC (Universal Functional Activity Coefficient) group contribution model and optimization method. The experimentally derived flash point was also compared with the predicted flash point. The two methods can estimate the flash point fairly well for the n-decane + n-octanol and acetic acid + n-butanol systems.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3253-3259
• /
• 2009

In this study, a computer simulation has been performed for the refrigeration cycle using mixed refrigerants in order to decrease the process stream temperature to $-20^{\circ}C$. Refrigerant supply temperature was assumed to be $-30^{\circ}C$ considering the temperature difference as $10^{\circ}C$ with process stream. Peng-Robinson equation of state model was selected for the computer simulation. A new alpha function proposed by Twu et al was used for an accurate prediction of pure component vapor pressure experimental data. One fluid mixing rules were used for the estimation of mixture vapor-liquid equilibria calculations. A commercial process simulator, PRO/II with PROVISION was utilized for the simulation of the overall refrigeration process. In order to minimize the compressor power consumption, we have optimized the two-stage compression system by varying the first stage compressor outlet pressure. Finally, we could obtain the minimum total power 755.7kW at the first stage compressor outlet pressure, 6 bar.

• Korean Chemical Engineering Research
• /
• v.56 no.2
• /
• pp.204-211
• /
• 2018

In this study, densities of water + N-Methyldiethanolamine (MDEA), Water + 2-Amino-2-Methyl-1-Propanol (AMP), MDEA + AMP binary systems and Water+MDEA+AMP ternary system were measured over the full range of composition at temperatures from 303.15 K to 333.15 K by using an Anton Paar digital vibrating tube densimeter (DMA4500). The experimental excess volumes have been obtained from the experimental density results and have been fitted using the Redlich-Kister-Muggianu expression. The parameters obtained from the binary excess volume data were used for the correlation of ternary system with one additional ternary parameter for each isotherm. All investigated binary and ternary systems are completely miscible, because the values of excess volume are negative under the examined conditions.

• Applied Chemistry for Engineering
• /
• v.9 no.6
• /
• pp.924-929
• /
• 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.

• Fire Science and Engineering
• /
• v.25 no.3
• /
• pp.113-118
• /
• 2011

The flash point is an important indicator of the flammability of a chemical. The minimum flash point behaviour (MFPB) is exhibited when the flash point of a mixture is below the flash points of the individual components. The identification of this behaviour is critical, because a hazardous situation results from taking the lowest component flash point value as the mixture flash point. In this study, the flash points for the n-butanol + n-decane and n-octane + n-propanol systems which exhibit MFPB, were measured by Tag open-cup apparatus. The experimental data were compared with the alues calculated by the Raoult's law, the van Laar equation and the Wilson equation. The calculated values based on the van Laar and Wilson equations were found to be better than those based on the Raoult's law. It was concluded that the van Laar and Wilson equations were more effective than the Raoult' law at describing the activity coefficients for non-ideal solution such as the n-butanol + n-decane and n-octane + n-propanol systems. The predictive curve of the flash point prediction model based on the Wilson equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the van Laar equation.

• Journal of the Korean Institute of Gas
• /
• v.16 no.5
• /
• pp.41-46
• /
• 2012

The flash point the lowest temperature at which the concentration of vapor of the substance in the air reaches the lower flammability limit(LFL), and is one of the most important physical properties used to determine the potential for fire and explosion hazards of industrial materials. The most published flash point data was for pure components and the flash points of the binary solutions that have flammable components, appear to be scarce in the literature. In the present study, the flash points of tert-pentanol+n-decane system were measured by Tag open-cup tester. The measured data were compared with the values calculated by the Raoult's law and the optimization methods based on the Wilson and NRTL equations. The calculated values by optimization methods were found to be better than those based on the Raoult's law.

• Journal of the Korean Institute of Gas
• /
• v.23 no.3
• /
• pp.40-45
• /
• 2019

Flash point is the important flammability indicator characterizing the risk of fire and explosion of flammable liquid mixture. In this study, flash points of water+formic acid and water+acrylic acid were measured by Seta flash apparatus. The flash points estimated by the methods based on empirical equation and Raoult's law were compared with experimental flash points. Absolute average errors of the results estimated by Raoult's law are $10.7^{\circ}C$ and $4.8^{\circ}C$ for water+formic acid and water+acrylic acid, respectively. Absolute average errors of the results estimated by empirical equation are $1.0^{\circ}C$ and $0.5^{\circ}C$ for water+formic acid and water+acrylic acid, respectively. In conclusion, the estimated values by empirical equation simulated the measured values better than those calculated by Raoult's law.

• Korean Chemical Engineering Research
• /
• v.43 no.5
• /
• pp.595-602
• /
• 2005

In order to purify diethylene glycol as main impurity included in p-dioxanone, SLE (solid-liquid equilibria) and mixture density on two components system of p-dioxanone and diethylene glycol were measured and a layered melt crystallization with seed has been applied. The SLE of p-dioxanone and diethylene glycol were a simple eutectic system and the temperature and PDX concentration at eutectic point were 0.08 and 246 K, respectively. Densities of their binary mixtures were well fitted by the best correlation equation, ${\rho}_l=0.405+1.361x+0.002T-0.004xT$. In the melt crystallization, the growth rate (G) was proportional to the 1.5th power of the subcooling degree. The effective distribution coefficient ($K_{eff}$) as the degree of impurity removal was observed to increase with increasing the growth rate and initial p-dioxanone concentration. And also, $K_{eff}$ was correlated with Z function using Wintermantel's model such as $K_{eef}=-0.0604+6.392{\times}Z$. Finally, PDX purity through the optimization of this process can be obtained over 99%.

• Korean Chemical Engineering Research
• /
• v.43 no.3
• /
• pp.366-370
• /
• 2005

Pervaporation process using a NaY zeolite membrane was applied for separation of water generated in an esterification process as a byproduct. From the binary mixture of water and either ethyl acetate or acetic acid and the ternary mixture of water, ethanol and ethyl acetate which might be present in an esterification reaction for manufacturing ethyl acetate, water was separated by the membrane pervaporation. It was investigated how the operating parameters such as an organic concentration and a temperature affected the permeate flux and the separation factor of water. For the feed mixture of water/ethyl acetate, the total flux and the separation factor of water were observed to be $930-5,000g/m^2/hr$ and 3,700-8,000, respectively. Also it was found for ternary mixtures of water/ethanol/ethyl acetate that the total flux was $1,300-3,900g/m^2/hr$ and the separation factor was 530-1,600. A pervaporation process might be applied in an esterification process since both the total flux and the separation factor of water through the NaY zeolite membrane were shown to be very high.