• Clean Technology
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• v.24 no.3
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• pp.157-165
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• 2018

In this study, the removal of $Si_3N_4$ particles from the surface of a silicon wafer was investigated by using supercritical carbon dioxide, the IPA co-solvent and cleaning additive chemicals. First, the solubility of several surfactants and binders in supercritical carbon dioxide solubility and particle dispersibility in the binders were evaluated in order to confirm their suitability for the supercritical cleaning process. Particle removal experiments were carried out with adjusting various process parameters and reaction conditions. The surfactants used in the experiment showed little particle removal effect, producing secondary contamination on the surface of wafers. On the other hand, 5 wt% (with respect to $scCO_2$) of the cleaning additive mixture of trimethyl phosphate, IPA, and trace HF resulted in 85% of particle removal efficiency after $scCO_2$ flowing for 4 minutes at $50^{\circ}C$, 2000 psi, and the flow rate of $15mL\;min^{-1}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.207-212
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• 2001

Supercritical fluid extraction was explored as a method for removing lipids and bad odor from tuna viscera. Selected conditions of extraction pressure, time, temperature and sample size were evaluated for effective removal of lipids and bad odor, Supercritical carbon dioxide was used as a solvent and the extraction was performed at semi-batch flow type. The experimental conditions used in this work was the range of pressure from 1,500 psig to 2,000 psig, the temperature from $25^{\circ}C\;to\;40^{\circ}C$ and dried sample size from 0.2 mm to 1.0 mm. The main fatty acids extracted from tuna viscera were palmitic acid (16: 0) heptadecenoic acid (17: 1) oleic acid (18: 1) and docosahexaenoic acid (22: 6). Protein concentrate was obtained without deformation the optimum condition at $35^{\circ}C$, 1,800 psig and 0.25 mm of the size. In the concentrate after supercritical carbon dioxide extraction, the major amino acids were glutamic acid, leucine and lysine.

• Plant Journal
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• v.15 no.2
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• pp.42-45
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• 2019

The molten carbonate fuel cell has a high temperature of waste heat and can constitute a bottoming cycle to increase the efficiency. Previous study used a bottoming cycle as steam turbine cycle. In this study, we are going to replace the bottoming cycle with a supercritical carbon dioxide power cycle. The system power was compared to consider replacing the bottoming cycle. As a result, the power of the supercritical carbon dioxide power cycle at the present development stage is lower than that of the steam turbine cycle, but theoretically, the power can be larger than the steam turbine cycle. If the supercritical carbon dioxide power cycle improves the isentropic efficiency of the turbine by 89%, the isentropic efficiency of the compressor by 83%, and the effectiveness of the recuperator by 0.9, the power can be same to the steam turbine cycle.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.737-741
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• 1997

The typical removal method of volatile organic compounds is adsorption process. In this study, granular activated carbon and activated carbon fiber were used as adsorbents, and the adsorption behavior for the two types of adsorbent was compared. And they were regenerated by supercritical carbon dioxide extraction at a constant temperature, 318.15 K, and 2000, 2500, 3000 psi respectively. The desorption percentage of initial adsorbates and iodine values were increased with pressure of supercritical carbon dioxide. The regeneration time was 70 and 60 minutes in adsorbents loaded with methyl ethyl ketone(MEK) and benzene, respectively. The desorption percentages were 64.0% for granular activated carbon and 55.3% for activated carbon fiber loaded with MEK, and 59.1% for granular activated carbon and 45.2% for activated carbon fiber loaded with benzene. The exit concentration could be evaluated by Tan and Liou model. Therefore, the granular activated carbon and the activated carbon fiber could be regenerated by supercritical fluid extraction process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.1018-1023
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• 2010

This study was conducted to investigate quality changes of apple slab after pretreating with supercritical $CO_2$. L, a, b and color difference values were little changed at increasing temperature and pressure. Polyphenol oxidase was inhibited according to increment of supercritical $CO_2$ temperature and pressure. Springiness and hardness were increased at increasing pressure and temperature condition of pretreatment but hardness showed lower value than untreatment. The texture like sponge of dried apple slab was probably due to channels which were made during penetration and release of carbon dioxide.

• Journal of environmental and Sanitary engineering
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• v.16 no.4
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• pp.69-76
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• 2001

The catalytic oxidation of volatile organic compounds (VOCs), which were benzene and toluene, was studied in the supercritical carbon dioxide($SC-CO_2$) media. In $SC-CO_2$ media, the deep oxidation conversion of VOCs was increased with the temperature and pressure. The deep oxidation conversion in SC -$CO_2$ media is better than that in air media at same pressure condition. This can be explained by the solubility of VOCs in $SC-CO_2$. The many intermediates produced by the partial oxidation of VOCs were detected from off-line samples. The intermediates were Identified as benzene, toluene, benzaldehyde, phenol, naphthalene, 1,1`-biphenyl, benzoic acid, 3-methylphenol, 1,1'-(1,2-ethanediyl)bis- benzene, 1,1'-(1,2-ethene- diyl)bis-benzene, anthracene, and so on. The amount of intermediates was decreased as the molar radio of oxygen to carbon dioxide was decreased. When the molar ratio of oxygen to carbon dioxide was 1 : 16, the deep conversion was kept constant. Thus, the catalytic oxidation process in $SC-CO_2$ media can be combined on-line with supercritical fluid extraction of environmental matrices and supercritical regeneration of used adsorbent. Thus, the nontoxic $SC-CO_2$ media process was suggested as the new VOCs control technology.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.414-420
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• 2004

The heat transfer and pressure drop characteristics associated with the gas cooling of the supercritical carbon dioxide in a horizontal tube have been investigated experimentally. This problem is of particular interest in the design of a gas cooler of cooling systems using $CO_2$refrigerant. The test section is consisted of 6 series of 455 mm in length, 4.15 mm ID copper tube, respectively. The effects of the inlet temperature, pressure and mass flow rate on the heat transfer and pressure drop of $CO_2$in a horizontal tube is studied in detail. The heat transfer coefficient of $CO_2$is varied by temperature, inlet pressure, and mass flow rate of $CO_2$. This has maximum value at near the pseudocritical temperature. The pressure drop is changed by inlet pressure and mass flow rate of $CO_2$. The results have been compared with those of previous work. The heat transfer correlation at the supercritical gas cooling process is also suggested.

• KSBB Journal
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• v.26 no.1
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• pp.69-77
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• 2011

In this study, poly (L-lactic acid) (PLLA) microparticles containing gemcitabine hydrochloride were prepared by a supercritical fluid process, called aerosol solvent extraction system (ASES), utilizing supercritical carbon dioxide as antisolvent. The influence of process parameters such as temperature, pressure, $CO_2$ and solution flow rate, solution concentration, and feed ratio of drug to polymer on the morphology and characteristics of the microparticles was studied in detail. The gemcitabine-loaded microparticles exhibited a spherical shape with a smooth surface. The entrapment efficiency of gemcitabine increased with increasing temperature, solution concentration and $CO_2$ flow rate and with decreasing drug/polymer feed ratio. The maximum drug loading obtained from the ASES process was found to be about 11%. The ASES-processed PLLA microparticles containing gemcitabine showed a relatively high initial burst due to the presence of surface pores on the microparticles and the poor affinity between drug and polymer.

• KSBB Journal
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• v.17 no.2
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• pp.148-152
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• 2002

The extraction of volatile essential oil using supercritical carbon dioxide with 2%(v/v) ethanol and non-ethanol was performed in a semi-continuous flow extractor at the range of pressures and temperatures 6.9 to 17.2 MPa and 30 to 45$^{\circ}C$, respectively. When ethanol was added to the co-solvent, the solubility of volatile essential oils was increased up to 90% over the neat CO$_2$ value. The most efficiency of extraction of the voilatile essential oils was achieved at 13.8㎫ and 40$^{\circ}C$ by supercritical carbon dioxide with entrainer from Citrus junos peel.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.383-386
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• 2005

Grape seed oil made by press or organic solvent extraction does not contain resveratrol, a bioactive compound. Supercritical carbon dioxide could extract oil containing resveratrol from grape seed. The extraction efficiency was mainly dependent on the water content in grape seed. More resveratrol was contained in the oil extracted with un-dried grape seed. No resveratrol was extracted with dried grape seed. Time course changes of grape seed oil extraction also resulted that resveratrol could be extracted by supercritical carbon dioxide with the positive influence of water.