• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.162-170
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• 1996

Light cycle Oil(LCO) contains 2,6-dimethylnaphthalene (2,6-DMNA) which is used as the basic material for high performance engineering plastics and liquid crystal polymer. This study was experimentally investigated to concentrate a mixture of dimethylnaphthalene(DMNA) isomers in the LCO by extraction-distillation combination as a pretreatment for separation and purification of 2,6-DMNA in the LCO. Furthermore, concentration of a mixture of DMNA isomers in the LCO compared between distillation and extraction-distillation combination. The recovery of aromatics in the LCO was performed by batch cocurrent multistage extraction with dimethylsulfoxide and water mixture as solvent. The concentration of naphthalene group(carbon number 10-12) in the extracted mixture is higher than that in the LCO. The yield for naphthalene group increased with decreasing carbon number. The yield for a mixture of DMNA isomers obtained in 5 equilibrium extration runs was about 65%. the separation of individual components with extractedmixture was tested by batch distillation. Futhermore, for recovery of a mixture of DMNA isomers of high concentration, distillate containing DMNA was distilled. As a result, a mixture of DMNA isomers with high concentration such as 60wt% was recovered. The extraction-distillation combination was more effective than the distillation to concentration a mixture of DMNA isomer in the LCO.

• Clean Technology
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• v.19 no.1
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• pp.30-37
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• 2013

Low-rank coal with high water content (32.3 wt%) was dried by fry drying, and the fuel characteristics of the dried coal from which the oil was separated by using a high-speed centrifugal separator were analyzed. After fry drying for 6 min and 10 min, the water content decreased to 5.0 wt% and 4.2 wt% respectively. The higher calorific value (HCV) of the coal increased remarkably after fry drying, from 11,442.0 kJ/kg-wet. The oil content of the fry-dried coal was 15.0 wt% and it decreased with an increase in the reheating temperature: 9.7 wt% at $80^{\circ}C$ to 9.3 wt% at $100^{\circ}C$, and then to 8.5 wt% at $120^{\circ}C$. The recovered oil could then be reused. According to of thermogravimetric analysis (TGA), there was no difference in the weight loss patterns of the coal samples with different coal diameters at a reheating temperature of $120^{\circ}C$. This was because the amount of oil separated by the centrifugal separator was affected by the reheating temperature rather than the coal diameter. And derivative thermogravimetry (DTG) curves of raw coal before the fry-drying process, a peak is formed at $400^{\circ}C$ in which the volatile matter is gasified. In case of the fry-dried coal, the first peak is generated at $350^{\circ}C$, and the second peak is generated at $400^{\circ}C$. The first peak is caused by the oil that is replaced with the water contained in the coal during the fry-drying process. Further, the peaks of the coal samples in which the oil is separated at a reheating temperature of $80^{\circ}C$, $100^{\circ}C$, $120^{\circ}C$, respectively are smaller than that of the coal in which the oil is not separated, and this is caused by that the oil is separated by the centrifugal separator.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.430-434
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• 1987

Fatty acid fraction rich in ${\omega}-3$ polyunsaturated fatty acids (${\omega}-3$, PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) could be obtained by saponification of fish oil in ethanol containing alkali hydroxide followed by cooling and filtration of the resultant solution. Fatty acid compositions of fish oil and the concentrates suggest that the ratio of number of double bonds to carbon number in a fatty acid molecule is a more important factor than the degree of unsaturation or the chain length in determining the solubility of fatty acid salts in ethanol. Water content in ethano1 affected significantly the efficiency of the separation with respect to yield and content of EPA and DHA in the concentrates; the lower the water content, the higher the efficiency. It was, however, influenced little by cooling procedure and temperature which the saponified solution experienced during the crystallization. Under an optimal condition, the contents of EPA and DHA in the concentrate increased by 2.4 and 2.5 times, respectively, as compared with those in sardine oil.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.1-7
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• 2017

Polydimethylsiloxane (PDMS) can be deposited on various substrates using chemical vapor deposition process, which results in the formation of PDMS thin films with thickness below 5 nm. PDMS layers can be evenly deposited on surfaces of nanoparticles composed of various chemical compositions such as $SiO_2$, $TiO_2$, ZnO, C, Ni, and NiO, and the PDMS-coated surface becomes completely hydrophobic. These hydrophobic layers are highly resistant towards degradation under acidic and basic environments and UV-exposures. Nanoparticles coated with PDMS can be used in various environmental applications: hydrophobic silica nanoparticles can selectively interact with oil from oil/water mixture, suppressing fast diffusion of spill-oil on water and allowing more facile physical separation of spill-oil from the water. Upon heat-treatments of PDMS-coated $TiO_2$ under vacuum conditions, $TiO_2$ surface becomes completely hydrophilic, accompanying formation oxygen vacancies responsible for visible-light absorption. The post-annealed $PDMS-TiO_2$ shows enhanced photocatalytic activity with respect to the bare $TiO_2$ for decomposition of organic dyes in water under visible light illumination. We show that the simple PDMS-coating process presented here can be useful in a variety of field of environmental science and technology.

• Tribology and Lubricants
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• v.28 no.1
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• pp.33-37
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• 2012

Automotive wheel bearing grease helps to reduce stresses and prevent wear of wheel bearings. But it is easily contaminated by water and other contaminants. Previously, our research group reported the change of grease physical properties such as dropping point, work penetration and oxidation work stability, water washout characteristics, leakage tendency, oil separation, evaporation loss and rust protection by water contamination. In this paper, we analyzed the physical characteristics of grease such as lubricity, viscosity and total acid number to investigate the mechanism of thickener decomposition. In water contaminated grease, the total acid number and wear scar were increased, the viscosity was decreased due to the decomposition of lithium complex thickener.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1478-1486
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• 2018

Liquid crystals offer plenty of useful activities as improving the stability of emulsion, increasing moisturizing power, drug release, improving skin feeling and visual effect for cosmetics fields. In order to prepare stable semi-transparent gel emulsion, liquid crystal emulsification method was used. The emulsion stabilities of systems containing glycerin, fatty alcohols, surfactants, water and oil were investigated at various temperatures as time passed. The stabilities of all emulsions were evaluated by means of a polarizing microscope, SEM, rheometer, colorimeter and DSC. Even though the samples stored at $50^{\circ}C$ thermostatic chamber were occurred the reduction of hardness, turbidity and ${\Delta}H$ and the peak shift, the semi-transparent gel emulsion was very stable without separation between water and oils phase in emulsion.

• Membrane Journal
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• v.8 no.4
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• pp.228-234
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• 1998

Among various water contaminents, organic compounds like phenol are difficult to be removed or destroyed by conventional methods under the unusual discharge conditions. The separation of phenol from aqueous solution has been carried out by several methods recently: absorption by an activated carbon, solvent extraction and liquid membrane technology. The liquid membrane based on water-oil emulsification has been tested as an alternative technology of the conventional technology. In this work, tri-n-butyl phosphate(TBP) and liquid polymers were examined as a liquid membrane in the supported liquid membrane(SLM). The feed concentration of phenol was varied and various types of liquid membranes were used to examine their effects on separation of phenol. It was found that TBP, polypropylene glycol 4000(PPG 4000) and polybutytene glycol 500(PBG 500) were proper carriers because mass transfer rates through them were much higher than or similar to that through methyl isobutyl ketone(MIBK) which was used as a conventional solvent in a solvent extraction process.

• Clean Technology
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• v.10 no.2
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• pp.61-72
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• 2004

In this study, aqueous/semi-aqueous cleaning agents which consist of organic solvent, surfactant, cosurfactant, and water were developed by changing formulation parameters such as organic solvent type and contents, surfactant type and contents, and cosurfactant/surfactant(A/S) ratio, etc.. And physical properties and flux removal of the formulated cleaning agents have been evaluated. Also, the performance of oil-water separation from the rinse water contaminated during the cleaning process was evaluated for its recycling. The formulated cleaning agents in this work expected to have good penetration because of their low viscosity and low surface tension values of 30.2~32.5 dyne/cm. The flux removal with the terpene type cleaning agent was higher than that with hydrocarbon type cleaning agent and two commercial products (CPA(commercial product A), CPB(commercial product B)). And the performance of oil-water separation by gravity settling from the rinse water contaminated with formulated cleaning agent and soils was shown to be very good. The cleaning agents developed in this work were applied to surface mounting technology(SMT) cleaning process for manufacturing electronic parts at L electronic company. As a result, the newly developed cleaning agents showed two times better cleaning speed for removal of solder cream than the conventional ond containing ethanol and IPA(isopropyl alcohol). In addition, malodor and VOC problems generated by the previous organic cleaning agents have been solved in the manufacturing field through introduction of the non-volatile and environmental-friendly cleaning agents to the field.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.1
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• pp.89-97
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• 2017

Butanol has an ability to improve the ignition quality due to its lower latent heat of vaporization; it has an advantage to reduce a volume of a fuel tank because its energy density is higher than that of ethanol. Also, butanol-diesel oil blending quality is good because butanol has an effect to prevent the phase-separation between two fuels. Even if the blended oil contains water, it can reduce the corrosion of the fuel line. Thus, it is possible to use butanol-diesel oil blended fuel in diesel engine without modification, and it may reduce the environment pollution due to NOx and particulate and the consumption of diesel oil. Therefore, some studies are being advanced whether butanol is adequate as an alternative fuel for diesel engines, and the results of the combustion and exhaust gas emission characteristics are being presented. Though the injection and spray characteristics of butanol are more important in diesel combustion, the has not yet dealt with the matter. In this study, the influence in which differences of physical properties between butanol and diesel oil may affect the injection and spray characteristics such as injection rate, penetration, spray cone angle, spray velocity and process of spray development were examined by using CRDI system, injection rate measuring device and spray visualization system. The results exhibited that the injection and macroscopic spray characteristics of two fuels were nearly the same.