• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.988-993
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• 2012

Energy and cost analysis of the preprocessing for carbon capture and storage transportation such as supercritical compression and liquefaction is done using chemical simulation model. Direct compression to supercritical phase (process 1-1), liquefaction and pumping (process 1-2), carbon dioxide compression and expansion as a refrigerant itself (process 2), usage of other refrigerant with compression and expansion (process 3-1), with absorption chiller (process 3-2), cascade refrigeration (process 3-2) have been simulated and evaluated. The specific cost is about 4 to 7 $/ton.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.59-64
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• 1999

Supercritical fluid extraction (SFE) technique was applied to extract cytotoxic substances from five medicinal plants including Angelica gigas, Angelica acutiloba, Aralia cordata, Spirodela polyrhiza, Bupleurum falcatum, and Acanthopanax sessiliflorus. The cytotoxicities against P388, A549, and HL-60 cell lines were determined for the supercritical carbon dioxide extracts of five plant materials employed and were compared with those of the conventional organic solvent extracts such as n-hexane, $CHCl_{3}$, and MeOH to evaluate the SFE as an alternative method to conventional organic solvent extraction. In most cases, the SFE extracts of plant materials showed enhanced cytotoxicities when compared with those of other organic solvent extracts. In addition, the optimum temperature and pressure of SFE for extraction of the cytotoxic substances were largely affected by both the plant species and the cell lines tested. These results suggested that SFE could be an alternative to the conventional organic solvent method for the selective extraction of cytotoxic compounds from plants.

• Clean Technology
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• v.17 no.4
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• pp.300-305
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• 2011

A mixture of supercritical carbon dioxide and a co-solvent was employed to strip a high-dose ion-implanted photoresist (HDIPR) from the surface of semiconductor wafers. The stripping efficiency was highly improved by the physical force generated from a ultrasonication tip inside the reactor. In addition, helium gas was injected in the reactor as a barrier gas before the introduction of pure supercritical $CO_2$ ($scCO_2$), which reduced the rinsing time significantly. The effect of co-solvents on the stripping efficiency was investigated. The wafer surfaces were analyzed by scanning electron microscopy and by an energy dispersive X-ray spectrometer.

• KSBB Journal
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• v.18 no.4
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• pp.301-305
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• 2003

The study of pancreatin extraction was investigated by supercritical fluid process. Using supercritical carbon dioxide extraction with entrainer the purification of pancreatin was possible to remove lipids from Hog pancreas. To observe the optimum conditions different experimental variables were changed as pressure, temperature, flow rate of solvent and 0.25 mm of sample size were evaluated for effective removal of lipids. Ethanol and n-hexane were used as an entrainer with 5 mL/min. Increasing pressure at constant temperature the efficiency of the lipid removal in Hog pancreas was improved and the protein was concentrated without denaturalization, compared that of the control Hog pancreas. The most efficient conditions of lipid elimination were 17 MPa of pressure and 35$^{\circ}C$ of temperature and 0.25 mm of sample size.

• Journal of Powder Materials
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• v.21 no.6
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• pp.407-414
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• 2014

The powder injection molding process having advantages in manufacturing three-dimensional precision parts essentially requires a debinding process before sintering to remove the binders used for preparing feedstock. In this study, powder injection molding of translucent alumina was performed, and carbon dioxide ($CO_2$) is used as a supercritical fluid that makes it possible to remove a large amount of binder, which is paraffin wax. The relationship between the optical property of translucent alumina and the debinding condition (temperature and pressure) of supercritical $CO_2$ was investigated. As temperature and pressure increased, extraction rate of the binder showed rising tendency and average grain size after sintering process was relatively fine. On the other hand, optical transmittance was reduced. As a result, the debinding condition at $50^{\circ}C$ and 20 MPa that represents the lowest extraction rate, $8.19{\times}10^{-3}m^2/sec$, corresponds to the largest grain size of $14.7{\mu}m$ and the highest optical transmittance of 45.2%.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1254-1266
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• 2024

This study investigates the application of supercritical carbon dioxide (S-CO₂) direct-cycle micro modular reactors (MMRs) in primary frequency control (PFC), which is a scenario characterized by significant load fluctuations that has received less attention compared to secondary load-following. Using a modified GAMMA + code and a deep neural network-based turbomachinery off-design model, the authors conducted an analysis to assess the behavior of the reactor core and fluid system under different PFC scenarios. The results indicate that the acceptable range for sudden relative electricity output (REO) fluctuations is approximately 20%p which aligns with the performance of combined-cycle gas turbines (CCGTs) and open-cycle gas turbines (OCGTs). In S-CO₂ direct-cycle MMRs, the control of the core operates passively within the operational range by managing coolant density through inventory control. However, when PFC exceeds 35%p, system control failure is observed, suggesting the need for improved control strategies. These findings affirm the potential of S-CO₂ direct-cycle MMRs in PFC operations, representing an advancement in the management of grid fluctuations while ensuring reliable and carbon-free power generation.

• Journal of the Korean GEO-environmental Society
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• v.25 no.3
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• pp.5-11
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• 2024

Promising geological structures for carbon dioxide capture and subsurface storage include aquifers, depleted reservoirs, and gas fields. Among these, aquifers are gaining attention due to their potential for storing significant amounts of carbon dioxide compared to other geological structures. Therefore, there is a growing interest in enhancing carbon dioxide storage efficiency by understanding the characteristics of aquifers and developing technologies tailored to their properties. In this study, the storage efficiency of carbon dioxide injection following surfactant pre-injection into porous micro-models was evaluated. The results indicate that as the concentration of the surfactant solution injected prior to carbon dioxide injection increases, storage efficiency improves. Conversely, lower concentrations require more surfactant injection to enhance storage efficiency. Furthermore, under identical surfactant concentration conditions, the storage efficiency from surfactant pre-injection prior to supercritical carbon dioxide injection is approximately 30% lower compared to surfactant-co-solvent substitution as observed in previous studies. However, under the maximum concentration conditions investigated in this study, similar storage efficiencies to those of previous studies were achieved. These findings are expected to guide concentration determinations for surfactant application aimed at enhancing carbon dioxide storage efficiency in aquifers in future studies.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.732-737
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• 2018

Experimental data of phase equilibria are reported for the binary mixture of 1-phenyl-2-pyrrolidone in supercritical carbon dioxide. Phase behavior data was measured in a synthetic method at a temperature ranging from 333.2 to 393.2 K and at pressures up to 97.14 MPa. The solubility of 1-phenyl-2-pyrrolidone in the carbon dioxide + 1-phenyl-2-pyrrolidone system increased as temperature increased at a constant pressure and it exhibited the type-I phase behavior. The experimental data for the binary mixture were correlated with the Peng-Robinson equation of state using mixing rule and the critical properties of 1-phenyl-2-pyrrolidone were predicted with the Joback and Lyderson method.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.171-174
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• 2001

초임계유체(supercritical fluid, SCF)는 친환경적 용매로서 고분자 합성과 기능화를 비롯하여 RESS(rapid expansion of supercritical solution)와 초임계염색 등의 섬유공정 분야에서 연구자들의 흥미로운 관심을 받아 오고 있다. 초임계유체는 기체와 액체의 중간적인 특성을 가지면서도 가스와 같이 우수한 확산력을 가지며 또한 아주 낮은 점도를 갖는다. SCF 중에서 비교적 온화한 조건(31.1℃의 임계온도, 73.8기압의 임계압력, Figure 1)에서 초임계상태를 가질 수 있는 이산화탄소가 가장 많이 이용되고 있는데 이는 자원이 풍부하며 쉽게 회수하여 사용할 수 있어 응용 면에서 유리하다. (중략)

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1351-1355
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• 1998

A simple apparatus for adding a modifying solvent to supercritical CO2 extractant was described. Small, fixed volumes (typically 100 μL) of liquid modifying solvents were delivered during the extraction process by use of an in-line high pressure loop injector and an air pump. Without disconnecting the extraction cell from the supercritical fluid extraction system, the modifying solvent was repeatedly delivered. The solvent modification device was optimized during the extraction of carbaryl and bis(acetylacetonato) copper(Ⅱ). Extraction recoveries from spiked filter paper and soil samples ranged between 22% and 109%, depending on the analyte and matrix components. The addition of polar modifying solvents were necessary to improve the extractability of the nonpolar CO2.