• Korean Journal of Materials Research
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• v.16 no.9
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• pp.533-537
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• 2006

The effects of binary solvent mixtures with various ratios of toluene and ethanol on the properties of slurries and green sheets were investigated. Viscosity of slurry was changed by varying the ratio of solvent mixture which affected the solubility of binder. The relative solvency behavior of a solvent mixture could be predicted with the Hildebrand solubility parameter(${\delta}$) and hydrogen bonding index( ${\gamma}$). The minimum viscosity, the best dispersion of binder, was reached at the composition of toluene:ethanol=4:6, which corresponded to our forecast. The mechanical properties of green sheets related to evaporation of solvents were influenced by the composition of the solvent mixture. At the azeotrope the skin was formed on a drying cast during the drying process because of fast evaporation. At a range of concentrations over 50wt% toluene, green sheets could not be fully dried at low temperature due to excessive toluene. The mechanical properties of green sheets were excellent at the azeotrope-like composition of toluene:ethanol=4:6 which has a little excess of toluene over the azeotrope.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.490-496
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• 2017

We have designed an extractive distillation for separating maximum boiling azeotrope of acetone-chloroform system. PRO/II 9.4 was used to simulate the overall process. The VLE data adopted from Dortmund data bank was regressed to obtain a new set of binary interaction parameters. Three different entrainers were used for the separation process--dimethyl sulfoxide (DMSO), ethylene glycol (EG) and benzene--to test their viability for the acetone-chloroform system. Thermodynamic feasibility analysis was done through ternary map diagrams. Two different thermodynamic models, NRTL and UNIQUAC, were explored for the study of overall process.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.245-249
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• 2003

Vapor-liquid equilibrium data were obtained for system of propane + R227ea (Heptafluoropropane) over the temperature range from 253.15 K to 323.15 K at 10 K intervals. Experiments were performed in a circulation type apparatus by injecting vapor through liquid pool using a magnetic pump. This system forms azeotrope in the temperature range of this study. The experimental results were correlated with the Peng-Robinson (PR) equation of state and Redlich-Kwong-Soave (RKS) equation of state using the van der Walls one-fluid mixing rule and were compared with each other.

• Clean Technology
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• v.21 no.4
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• pp.217-223
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• 2015

In the present study, modelling and optimization of ethanol-n-heptane separation process were performed using pressure-swing distillation. The pressure-swing distillation process optimization was performed to obtain high purity ethanol and high purity n-heptane into a low-high pressure columns configuration and a high-low pressure columns configuration. The results of pressure-swing distillation process simulation and optimization using high-low pressure column configuration showed a reduced total reboiler heat duty at 5.8% which confirmed a more economical energy consumption.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1016-1023
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• 1994

In process of manufacturing acrylonitrile azeotrope of acetonitrile-water was come into being as by-product. For the purpose of recovering acetonitrile through solvent extraction process benzene, toluene, o-xylene, ethylacetate and monochlorobenzene as solvents were selected in order to separate acetonitrile from azeotrope of acetonitrile-water. In this study liquid-liquid equilibrium data were determined and consistency of the experimental data was investigated. The tie line and plait point for solvent(1)-water(2)-acetonitrile(3) system were determined at $25^{\circ}C$. The parameters in the NRTL, UNIQUAC and modified UNIQUAC model were predicted, distribution coefficient and selectivity of each solvent were determined respectively.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.450-456
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• 2015

In the present study, modelling and optimization of ethanol-benzene separation process were performed using pressure-swing distillation. Order to obtain a reliable results, vapour-liquid equilibrium (VLE) experiments of ethanol-benzene binary system were performed. The parameters of thermodynamic equation were determined using experimental data and the regression. The pressure-swing distillation process optimization was performed to obtain high purity ethanol and high purity benzene into a low-high pressure columns configuration and a high-low pressure columns configuration. The heat duty values of the reboiler from simulation were compared, and the process was optimized to minimize the heat duty.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1215-1220
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• 2004

Reactive distillation (RD) is a combination process where both separation and reaction are considered simultaneously in a single vessel. This kind of combination to enhance the overall performance is not a new attempt in the chemical engineering areas. The recovery of ammonia in the classic Solvay process for soda ash of the 1860s may be cited as probably the first commercial application of RD. The RD system has been used for a long time as a useful process and recently the importance of the RD is enlarged more and more. In addition to that, the application fields of RD are diversely diverged. To make the most of the characteristic of RD system, we must decide the best operating condition under which the process shows the most effective productivity and should decide the best control algorithm which satisfies an optimal operating condition. Phosgene which is a highly reactive chemical is used for the production of isocyanates and polycarbonates. Because it has high reactivity and toxicity, its utilization is increasingly burdened by growing safety measures to be adopted during its production. Dimethyl Carbonate (DMC) was proposed as a substitute of phosgene because it is non-toxic and environmentally benign chemical. In this study, RD is used for DMC production process and the transesterification is performed inside of column to produce DMC. In transesterification, the methanol and ethylene carbonate (EC) are used as the reactants. This process use homogeneous catalyst and the azeotrope exists between the reactant and product. Owing to azeotrope, we should use two distillation columns. For this DMC production process, we can suggest two configurations. One is EC excess process and the other is methanol excess process. From the comparison of steady state simulation results where the Naphtali-Sandholm algorithm is used, it showed the better performance to use the methanol excess process configuration than EC excess process. Then, the dynamic simulation was performed to be based on the steady state simulation results and the optimal control system was designed. In addition to that, the optimal operating condition was suggested from previous results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.708-715
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• 2016

The modelling and optimization of Methyl Ethyl Ketone (MEK)-Cyclohexane (CH) separation process were performed using pressure-swing distillation with a low-high pressure column and a high-low pressure column configuration. The optimization was performed for the number of theoretical stages, and the location of the feed tray of low column and high column to obtain high-purity MEK at the top. The total reboiler heat duty at the low-high pressure column configuration and high-low pressure column configuration were at 11.7667 Mkcal/h and at 10.3484 Mkcal/h, respectively. The results showed that total reboiler heat duty could be reduced to 12.05% using a high-low pressure column configuration.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.2
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• pp.212-217
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• 2006

An experimental study on Electro-electrodialysis (EED) for IS (Iodine-Sulfur) process which is well known as hydrogen production system was carried out for the HI concentration from HIx (HI: $H_2O$ : $I_2$ = 1 : 5 : 1) solution. The polymer electrolyte membrane and the activated carbon cloth were adopted as a cation exchange membrane and electrode, respectively. In order to evaluate the temperature effect about HI concentration in fixed molar ratio, three case of temperature were selected to $60^{\circ}C$, $90^{\circ}C$ and $120^{\circ}C$. The electro-osmosis coefficient and transport number of proton have been changed from 1.95 to 1.21 (mol/Faraday) and 0.91 to 0.76, respectively as temperature increase from $60^{\circ}C$ to $120^{\circ}C$. It can be realized that the HI mole fraction in final stage of EED experiments already over the quasi-azeotrope composition.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.136-142
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• 2002

HFC-134a is currently used as the refrigerant in automobile air-conditioner, replacing the ozone depleting refrigerant CFC-12. Although HFC-l34a has no ozone depletion potential, it has a relatively high global warming potential, approximately 1300 tins that of CO$_2$ over a 100 year time horizon. Therefore, HFC- l34a does not seem to be a perfect alternative refrigerant due to high GWP. For this reason, non-azeotrope refrigerant mixture have been proposed as a long-term and drop-in alternative to HFC-l34a in the automobile air-conditioning system which has variable operating conditions with changes in RPM and pressure ratio. In this study,OS-l2a of which thermodynamic properties are similar to those of HFC-l34a is selected among the mixed refrigerant. HFC-l34a and OS-l2a are examined experimently by the performance test in the same automobile air-conditioning system.