• Korean Journal of Food Science and Technology
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• v.49 no.3
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• pp.279-285
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• 2017

This study reviews the manufacturing characteristics of distilled liquor prepared using Saccharomyces cerevisiae 88-4 separated from traditional Nuruk. From analysis of soju mash (sool-dut) during the fermentation process, 17.2% of alcohol was detected in the final fermentation with succinic acid present at the highest level ($7,164.3{\pm}85.2ppm$). From the analysis of alcohol content in different distillation conditions, distillation condition No. 6 showed the lowest amount of alcohol ($29.6{\pm}0.0%$), whereas distillation condition No. 4 showed the highest amount ($59.9{\pm}0.1%$). N-propanol has been detected at the highest level in distilled liquor under conditions No. 1 and 4, each being $163.4{\pm}18.3$ and $174.0{\pm} 0.1ppm$, respectively. Isobutanol showed a tendency similar to n-propanol. Distilled liquor in conditions No. 1 and 4 has shown the highest acetaldehyde level, each being $303.4{\pm}4.5$ and $325.4{\pm}13.1ppm$, respectively. After distillation, 14 volatile substances were found in common, with isoamyl alcohol present at the highest levels in all the distilled liquors. Distillation conditions No. 3, 5, 6, and 7 have shown high levels of isobutanol that emits a banana-like fragrance and ethyl octanoate that emits a pleasant fruity and floral fragrance.

• Clean Technology
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• v.29 no.4
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• pp.262-271
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• 2023

Globally, the amount of waste plastics has been occurring to environmental problems. As a result, it is necessary to research methods that utilize waste plastic pyrolysis oil (WPPO) produced by pyrolysis. One such method being studied is utilizing WPPO as a naphtha feedstock. In this study, five types of WPPO were analyzed to determine whether they can be used as raw materials for naphtha. Because of their wide boiling point range, the WPPOs were fractionated into light and heavy fractions through vacuum distillation, and the separation and purification techniques were analyzed using GC-VUV to determine the content of paraffin, olefin, and other compounds. All WPPOs showed high olefin content regardless of the source and fraction. Aromatic and paraffin content varied depending on the source, and oxygen and other compounds also varied significantly by source and fraction. In addition, the light fraction showed a carbon distribution similar to that of naphtha, whereas the heavy fraction showed a carbon distribution of C₁₁ ~ C₁₄. In conclusion, additional processes and raw material selection are required to utilize waste plastic pyrolysis oil as a raw material for naphtha.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.4
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• pp.451-460
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• 2013

The purpose of this study is to investigate the volatile compounds of Korean traditional gochujang from various districts. The volatiles from each traditional gochujang are being extracted by simultaneous steam distillation extraction (SDE), and analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Twenty compounds are identified as major volatile components which include 8 esters, 4 alcohols and 4 acids. The most traditional gochujang possesses more volatile components rather than commercial gochujang products. Most acids come from fatty acids and the alcohols derive from the oxidative degradation of linolenic acid. The most abundant volatile compounds for both traditional and commercial gochujang include 10 compounds such as 2-methyl-1-propanol, hexanal, 2-methyl-1-butanol, octanoic acid ethyl ester, as well as the various type of acids and esters. They represent most of the total GC peak areas, respectively. From the results, the characteristics of the flavors for traditional gochujang from each district are not clear but have shown various components than the commercial products.

• Journal of the Korean Applied Science and Technology
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• v.19 no.4
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• pp.258-264
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• 2002

Pyrolysis of polypropylene(PP) Was performed to find the effects of the pyrolysis temperature(425, 450, 475 and $500^{\circ}C$) and the pyrolysis time(35, 50 and 65minutes), respectively. Conversion and liquid yield obtained during PP pyrolysis continuously increased with the pyrolysis temperature( up to $500^{\circ}C$) and the pyrolysis time(up to 65minutes), especially these were more sensitive to the pyrolysis time at $425^{\circ}C$ than other pyrolysis temperatures. Each liquid product formed during the pyrolysis was classified into gasoline, kerosene, light oil and wax according to the distillation temperature based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The liquid products of PP pyrolysis up to $450^{\circ}C$ were almost same fractions($26{\pm}3$wt.% gasoline, $20{\pm}2$wt.% kerosene and $23{\pm}2$wt.% light oil) except wax($3{\sim}13$wt.%). On the other hand, the pyrolysis of PP from $475^{\circ}C$ to $500^{\circ}C$ produced $26{\pm}3$wt.% wax, $24{\pm}1$wt.% gasoline, $18{\pm}1$wt.% kerosene and $16{\pm}1$wt.% light oil. After all, the main liquid product changed from gasoline to wax with increasing pyrolysis temperature.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.307-312
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• 2001

Flavor compounds in Neungee (sarcodon aspratus) were extracted by simutaneous distillation and extraction (SDE), supercritical fluid extraction (SFE) and headspace method. Flavor compounds obtained by various extraction methods were analyzed with GC and GC-MS. The funtionality of flavor compounds were determined by aroma extract dilution analysis (AEDA) of GC-ofactometry methods. Fifty one flavor compounds were totally identified in Neungee mushroom. However, the numbers of flavor extracted SDE, SFE and headspace were 33, 26 and 17 respectively. The major flavor compounds obtained by SDE, SFE and headspace were 1-octen-3-ol, 1-octen-3-one, 3-octanone, 2-octen-1-ol, 3-octanol, 1-octanol and benzenealdehyde. As the results of sniffing test, the major flavor compounds were found to be fresh mushroom flavor, wood flavor, refreshing sweet flavor, mold flavor, bitter-mushroom and metalic-flavor.

• Clean Technology
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• v.17 no.4
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• pp.329-335
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• 2011

$SF_6$ gas is well known as a global warming gas. Global warming potential of $SF_6$ gas is 22,000 times higher than that of $CO_2$. Recycling of $SF_6$ gas is an essential technology for the sake of the environment and the economy. The recovery processes of $SF_6$ gas studied in this work were liquefaction, distillation, and crystallization processes because these processes were thought to be easily carried to the fields for recycling waste $SF_6$ gas. The processes were simulated and optimized using Aspen plus. The optimization problems were formulated to minimize energy consumption with satisfying product specification and desired recovery. The performance of the processes was compared based on the optimization results. Effects of major process variables on the recovery performance were investigated and optimal operation guide for changing product specification and product recovery was provided.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.243-248
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• 2005

Membrane pervaporation processes could have advantages over distillation for separation of water/organics mixtures: a low energy demand and the ability to separate azeotropic mixtures or isomers. Zeolite membranes might show better thermal, mechanical and chemical stabilities than polymer membranes. Water could be effectively separated from water/organic mixtures using the NaA zeolite membrane because of its high hydrophilicity. In this study, water was separated by pervaporation using the NaA zeolite membrane from water/ethanol mixtures. As a mole fraction of ethanol increased, the total permeation flux and the water flux decreased while the separation factor increased, reached a maximum point, and decreased. As an experimental temperature increased, the total permeation flux increased while the separation factor increased at the lower mole fraction of ethanol than 0.8 and it decreased at the higher mole fraction of ethanol than 0.8. The total permeation flux and the separation factor could be maintained constant during the long term experiment longer than 160 hours. It was found that the NaA zeolite membrane synthesized in our study showed better performance on water/ethanol separation than that of a distillation process or PVA polymeric pervaporation membranes.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.287-298
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• 2019

Lotus leaf has a special dual micro and nano surface structure which gives its highly hydrophobic surface characteristics and so-called self cleaning effect. In order to endow PVDF hollow fiber membrane with this special structure and improve the hydrophobicity of membrane surface, PVDF hollow fiber composite membranes was obtained through the immersion coating of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) dilute solution on the outside surface of PVDF support membrane. The prepared PVDF composite membranes were used in the vacuum membrane distillation (VMD) for the desalination. The effects of PVDF-HFP dilute solution concentration in the dope solution and coating time on VMD separation performance was studied. Membranes were characterized by SEM, WCA measurement, porosity, and liquid entry pressure of water. VMD test was carried out using $35g{\cdot}L^{-1}$ NaCl aqueous solution as the feed solution at feed temperature of $30^{\circ}C$ and the permeate pressure of 31.3 kPa. The vapour flux reached a maximum when PVDF-HFP concentration in the dilute solution was 5 wt% and the coating time was kept in the range of 10-60 s. This was attributed to the well configuration of micro-nano rods which was similar with the dual micro-nano structure on the lotus leaf. Compared with the original PVDF membrane, the salt rejection can be well maintained which was greater than 99.99 % meanwhile permeation water conductivity was kept at a low value of $7-9{\mu}S{\cdot}cm^{-1}$ during the continuous testing for 360 h.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.442-448
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• 2021

Seawater desalination is a technology through which salt and other constituents are removed from seawater to produce fresh water. While a significant amount of fresh water is produced, the desalination process is limited by the generation of concentrated brine with a higher salinity than seawater; this imposes environmental and economic problems. In this study, characteristics of seawater from three different locations in South Korea were analyzed to evaluate the feasibility of crystallization to seawater desalination. Organic and inorganic substances participating in crystal formation during concentration were identified. Then, prediction and economic feasibility analysis were conducted on the actual water flux and obtainable salt resources (i.e. Na2SO4) using membrane distillation and energy-saving crystallizer based on multi-stage flash (MSF-Cr). The seawater showed a rather low salinity (29.9~34.4 g/L) and different composition ratios depending on the location. At high concentrations, it was possible to observe the participation of dissolved organic matter and various ionic substances in crystalization. When crystallized, materials capable of forming various crystals are expected. However, it seems that different salt concentrations should be considered for each location. When the model developed using the Aspen Plus modular was applied in Korean seawater conditions, relatively high economic feasibility was confirmed in the MSF-Cr. The results of this study will help solve the environmental and economic problems of concentrated brine from seawater desalination.

• Journal of environmental and Sanitary engineering
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• v.11 no.2
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• pp.65-73
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• 1996

The objective of this study is to investigate the removal efficiency of volitile organic compounds in soil, and the mechanism of desorption by bench scale microwave heating, Silt soil used for experiment and was impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene and the microwave treatment was conducted in a modified domestic microwave oven : 2450MHz, 700W. According to the results of the research the removal efficiency was improved with increasing water contents and the soil temperature appeared to plateau period extending to 2-3minutes corresponds to the temperature a which steam distillation was expected. The value of removal rate constant (k) were calculated on dry and moisty silt soil, respectively, which showed linear with increasing microwave heating time. Therefore, addition of a certain amount of water to the contaminated soil can efficiently enhance the ability of the soil to absorb microwave energy and promote the evaporation of the volitile contaminants.