• Clean Technology
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• v.17 no.3
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• pp.266-272
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• 2011

Anchovy oil was extracted using supercritical carbon dioxide ($SCO_2$) and organic solvents. Extraction was carried out at temperature range from 40 to $60^{\circ}C$, and pressure range from 15 to 25 MPa. The flow rate of $CO_2$ (22 $gmin^{-1}$) was constant entire the extraction period of 1.5 h. The fatty acid composition of anchovy oil was analyzed by gas chromatography (GC). The main fatty acids of anchovy oil were myristic acid, palmitic acid, stearic acid, palmitoleic acid, EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). In addition, the oil obtained by $SCO_2$ extraction contained a higher percentage of polyunsaturated fatty acids especially EPA and DHA comparing to the organic solvent extracted oil. The oxidative stability of oils extracted from Anchovy by $SCO_2$ extraction was compared to those extracted by organic solvents. Results showed that the storage periods of oils obtained by $SCO_2$ extraction were longer than those of organic solvents extraction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.213-217
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• 2001

In order to develop a new separation technology, supercritical fluid extraction process was used to produce high purity pigments and fatty acids from seaweed (Undaria pinnatifida). Supercritical carbon dioxide was used as a solvent and ethanol as an entrainer. The sample was treated by a frozen drier and experiments were conducted with a semi-batch flow system at various operating conditions (pressure range, $10.3\~17.2$ MPa; temperature range, $30\~45^{\circ}C$: particle size, $500\~1,000{\mu}m$ extraction time, 60 min). Characteristics of the recovered pigment (chlorophyll a) and fatty acids were determined by UV-spectrophotometry and gas chromatography, respectively. The highest extraction efficiency for fatty acids and pigments was achieved at 12.4 MPa, $35^{\circ}C$, $500{\mu}m$of seaweed size.

• KSBB Journal
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• v.21 no.2
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• pp.157-163
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• 2006

A supercritical fluid process, called aerosol solvent extraction system(ASES), is especially suitable to the pharmaceutical, cosmetic and food industries due to its environmentally-friendly, non-toxic and residual solvent-free properties. In particular, the application of the ASES process to the processing of thermo-labile bioactive compounds has received attention of many scientists and engineers because of its low-temperature operating conditions. Unstable substances such as Vitamin-C and Vitamin-A can be effectively protected from degradation during the preparation process, because the ASES process is free from oxygen and moisture. In this study, Vitamin-C was formulated with 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta$-CD) for enhancement of Vitamin-C stability and bioavailability using the ASES process. To investigate the influence of the preparation process on the stability of Vitamin-C, Vitamin-C/HP-${\beta}$-CD inclusion complexes were prepared using both conventional solvent evaporation method and ASES process, and stored in a 50 mM phosphate buffer solution of pH 7.0 at $25^{\circ}C$ for 24 hours. From the experimental results, the stability of the Vitamin-C/HP-${\beta}$-CD inclusion complex prepared from the ASES process was found to be much higher than that of pure Vitamin-C and the Vitamin-C/HP-${\beta}$-CD inclusion complex prepared by the solvent evaporation method. The stability of Vitamin-C was observed to increase with the decrease of temperature at a constant pressure or with the increase of pressure at a constant temperature.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.293-301
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• 2017

A Sub-kWe small-scale experimental test loop was manufactured to investigate characteristics of the supercritical carbon dioxide power cycle. A high-speed turbo-generator was also designed and manufactured. The designed rotational speed of this turbo-generator was 200,000 rpm. Because of the low expansion ratio through the turbine and low mass flowrate, the rotational speed of the turbo-generator was high. Therefore, it was difficult to select the rotating parts and design the turbine wheel, axial force balance and rotor dynamics in the lab-scale experimental test loop. Using only one channel of the nozzle, the partial admission method was adapted to reduce the rotational speed of the rotor. This was the world's first approach to the supercritical carbon dioxide turbo-generator. A cold-run test using nitrogen gas under an atmospheric condition was conducted to observe the effect of the partial admission nozzle on the rotor dynamics. The vibration level of the rotor was obtained using a gap sensor, and the results showed that the effect of the partial admission nozzle on the rotor dynamics was allowable.

• Journal of the KSME
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• v.55 no.7
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• pp.32-36
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• 2015

최근 화석 연료의 과다 사용에 따른 에너지 자원 고갈 및 환경오염에 대한 우려가 증가함에 따라 비화석연료 기반의 재생가능하고 지속가능하며, 환경친화성이 높은 에너지에 대한 관심이 급증하고 있다. 농산폐기물, 폐목재, 에너지작물, 도시고형폐기물, 미세조류, 거대조류 등 육상 및 해상에서 발생하는 바이오매스는 재생가능한 에너지원으로서 화석원료와는 달리 사용 후 발생하는 이산화탄소를 다시 흡수하는 탄소중립(carbon-nutral)의 특성을 갖고 있어 전세계적으로 많은 주목을 받고 있다. 바이오연료 중 당질계원료를 이용하는 바이오에탄올 및 식물성유지를 이용하는 바이오디젤은 현재 상업적인 생산이 이루어지고 있으나, 이들 1세대 바이오연료는 식량자원과의 경쟁이라는 원천적인 한계를 가지고 있고, 분자구조식에 산소를 포함하고 있기 때문에 기존 화석원료에서 출발하는 가솔린, 항공유 및 디젤과 비교하였을 때 에너지 함량이 낮은 단점이 있다. 따라서 기존 1세대 바이오연료에서 탈피하여, 식량자원과 경쟁이 없으며, 또한 분자구조식에 산소를 적게 포함하거나 아예 포함하지 않는 바이오연료("drop-in" 바이오연료) 생산에 많은 관심이 집중되고 있다. 이 글에서는 최근 그린공정으로 대표되는 초임계 유체를 이용한 "drop-in" 바이오연료를 제조하기 위한 바이오매스 액화의 기술동향을 소개하고자 한다.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.93-97
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• 1997

$CO_2$ gas를 초임계상태의 유체로하고 그 용매에 코팅물질인 파라핀을 용해시켜 초임계 분출법(RESS)에 의해 핵입자 코팅을하여 복합입자를 제조하였고 그 용출 특성을 고찰하였다. 핵입자로는 입도분포가 다른 Glassb eads, Brilliant Blue(이하 BB)를 피복한 Glass beads, 분무건조법으로 제조한 염기성 탄산마그네시아의 Microcapsule(이하 MHC MC)을 사용하였다. 제조된 복합분체 표면을 SEM으로 관찰하였고 FT-IR을 사용하여 표면의 성분분석을 하였다. BB로 피복시킨 Glass beads는 Spectrophotometer로 BB가 용출되는 시간을 측정하였고 AA로 MHC MC중 Mg2+ ion의 release time이 7min, 26min, 30min으로 반응부에서 포집한 시료의 용출특성이 제일 우수하였다.

• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.347-349
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• 2007

지구 온난화를 일으키는 온실 가스 중의 하나인 이산화탄소($CO_2$)를 Epoxide와 Tetrabutylammonium bromide를 촉매로 하여 합성하여, 초임계 $CO_2$ 상태($Tc=31.06^{\circ}C$, Pc=7.38MPa)에서 반응하여 그에 따른 수율을 측정한 결과 초임계하에서는 현저한 수율의 증가를 확인하였다.

• Clean Technology
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• v.11 no.4
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• pp.171-179
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• 2005

Biodiesel is synthesized by transesterification of vegetable or animal oils with alcohols. Since it has similar characteristic with diesel fuel, it can be used as a fuel by mixing with diesel fuel. Moreover, it is advantageous that biodiesel can reduce air pollution emitted from fuel combustion and is produced from sustainable energy, biomass. Recently, many researchers have investigated biodiesel synthesis using supercritical methanol since it is economical due to shorter reaction time and simple separation/purification process, compared with conventional alkali- or acid-catalyzed process. By the development of biodiesel production process from waste edible oil using supercritical methanol, it can be expected to utilize potential energy resources, reduce carbon dioxide emission, and improve environmental conditions.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2003.04a
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• pp.83-86
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• 2003

기존의 습식염색법이 에너지 다소비형일 뿐만 아니라 분산염료를 이용해 PET, Nylon과 같은 합성섬유를 염색할 때 첨가되는 조제(계면활성제, 균염제, 유연제 등)가 난분해성 폐수를 유발시킨다. 이를 방지하기 위한 새로운 초임계염색법이 1991년 독일의 Schollmeyer 교수에 의해 보고된 이후, 한국, 미국, 이태리, 프랑스 등에서도 이에 관한 연구가 활발히 진행되어 현재 많은 연구 성과를 거두고 있다. (중략)

• Elastomers and Composites
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• v.34 no.3
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• pp.239-246
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• 1999

Side wall samples from a used automotive tire were subjected to subcritical and supercritical decomposition and extraction with three solvents, water, 28% ammonia solution and ammonia. For 6mm cube samples the rate of supercritical extraction with water followed a first-order kinetics with an activation energy of 140 kJ/mol. Solvent power of 28% ammonia so lotion at supercritical condition was found to be higher than supercritical water at initial extraction as pressure decreased. These phenomena were considered to be an effect of ammonia involved in water.