• Textile Coloration and Finishing
• /
• v.32 no.2
• /
• pp.80-88
• /
• 2020

Supercritical fluid dyeing is a new alternative to the conventional aqueous process because of its environmental benefits. In this study, dyeing properties of Nylon 6 fabrics were investigated depending on dyeing temperature and pressure in supercritical CO₂ fluid dyeing system. In order to select the optimal condition for supercritical fluid dyeing of Nylon 6 fabrics, dyeing temperature and pressure were varied from 100, 110, 120℃, 200, 230, 260bar, respectively. The results of K/S values and levelling properties showed that the optimal dyeing condition for Nylon 6 fabrics was 110℃ and 230bar in the supercritical CO₂ fluid dyeing system. The washing fastness ratings of the dyed Nylon 6 fabrics under supercritical medium were good for both fading and staining except for staining on nylon.

• Journal of the Korean Ceramic Society
• /
• v.40 no.12
• /
• pp.1220-1223
• /
• 2003

TiO$_2$ and TiO$_2$-CdS which were expected to be highly activated photocatalysts with semiconductor properties, were prepared using supercritical fluid method. The powders prepared by supercritical fluid were agglomerate foam in 2-3 ${\mu}{\textrm}{m}$ size and the primary particles of 20 nm were arranged in the powders. The powders which were prepared by supercritical fluid method were anatase phase without any heat treatment.

• Textile Coloration and Finishing
• /
• v.31 no.1
• /
• pp.25-32
• /
• 2019

The influence of the contact amount of carbon dioxide per unit mass of dyestuff(${\alpha}$) on dyeing uniformity in supercritical fluid dyeing is analyzed in this study. The experiments using a 5L class Pilot Scale dyeing machine is carried out for this study purpose. For a fixed temperature and pressure, the amount of sample and the dyeing leveling time were considered as process variables. The results show that the increase in the amount of the sample causes a higher color difference than the reference sample, and it also increases the amount of residual dye. On the other hand, the color difference tended to decrease with the increase in dyeing time. Based on these results, the correlation between ${\alpha}$ value and dyeing uniformity in supercritical fluid dyeing is obtained.

• Nuclear Engineering and Technology
• /
• v.54 no.9
• /
• pp.3540-3550
• /
• 2022

The supercritical carbon dioxide (S-CO₂) Brayton cycle is an important energy conversion technology for the fourth generation of nuclear energy. Since the printed circuit heat exchanger (PCHE) used in the S-CO₂ Brayton cycle has narrow channels, Rayleigh-Bénard (RB) convection is likely to exist in the tiny channels. However, there are very few studies on RB convection in supercritical fluids. Current research on RB convection mainly focuses on conventional fluids such as water and air that meet the Boussinesq assumption. It is necessary to study non-Boussinesq fluids. PRB convection refers to RB convection that is affected by horizontal incoming flow. In this paper, the computational fluid dynamics simulation method is used to study the PRB convection phenomenon of non-Boussinesq fluid-supercritical carbon dioxide. The result shows that the inlet Reynolds number (Re) of the horizontal incoming flow significantly affects the PRB convection. When the inlet Re remains unchanged, with the increase of Rayleigh number (Ra), the steady-state convective pattern of the fluid layer is shown in order: horizontal flow, local traveling wave, traveling wave convection. If Ra remains unchanged, as the inlet Re increases, three convection patterns of traveling wave convection, local traveling wave, and horizontal flow will appear in sequence. To characterize the relationship between traveling wave convection and horizontal incoming flow, this paper proposes the relationship between critical Reynolds number and relative Rayleigh number (r).

• Bulletin of the Korean Chemical Society
• /
• v.35 no.10
• /
• pp.3107-3110
• /
• 2014

• Textile Coloration and Finishing
• /
• v.31 no.1
• /
• pp.48-64
• /
• 2019

With evolution in the production environment of the textile industry, the need for non-water-based dyeing technologies and eco-friendly process facilities in the dyeing and processing stages has increased. In recent years, supercritical fluid dyes have been developed and commercialized in Europe, centering on this demand. However, so far, such dyes have been mainly applied in the processing of PET fibers. Basic research has mainly involved investigation of dyeing by supercritical carbon dioxide or solubility of such dyes, and more in-depth research should be continuously carried out. In this review, we describe the types and characteristics of supercritical fluids that exhibit specific properties at pressures and temperatures over the critical point. In addition, the state of the art in the dyeing and processing technology using supercritical fluids and associated, processing problems, environmental regulation, and wastewater treatment issues are described in detail. We hope this review can contribute to the supercritical fluid technology being further developed as an environment friendly dyeing processing method. Furthermore, we expect that the technique can be used as a means of ensuring different, high-quality dyed products.

• Korean Chemical Engineering Research
• /
• v.45 no.4
• /
• pp.384-390
• /
• 2007

In this study, electroless plating of copper was performed on PET film by using the blend of supercritical $CO_2$ and plating solution. The optimum volumetric ratio of supercritical fluid and plating solution was found to be 1:9 and dispersion property was poor at $CO_2$ vol% langer than 10%. Electroless plating of copper was best at $25^{\circ}C$ and 15 MPa. Role of added supercritical $CO_2$ is not to increase solubility but to disperse and maintain Cu-particles as the 1st particles.

• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.609-613
• /
• 2005

Daidzein and genistein were extracted from Korean soybean by supercritical $CO_2$ and sub/supercritical water. The extracted sample was analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). The retention time, retention factor, column efficiency, column selectivity and resolution of aglycons were compared with the change in the temperature and pressure of supercritical fluid and ethanol concentration. The characteristics of extraction of daidzein and genistein were more affected by ethanol concentration using supercritical $CO_2$. The most desirable extraction yield was obtained by supercritical $H_2O$ with $400^{\circ}C$ and 250 bar. Generally, the extraction yield of aglycons increased over 10 times using supercritical $CO_2$ than sub/supercritical $H_2O$.

• Journal of the Korean Ceramic Society
• /
• v.39 no.11
• /
• pp.1023-1027
• /
• 2002

In this paper, we have prepared phase-pure $SrTiO_3:\;Pr^{3+}$ phosphor powder by Supercritical Fluid Mixing using $Sr(OH)_2{\cdot}8H_2O$ and $TiO_2$ powders as starting materials. Its luminescent properties were investigated in comparison with $SrTiO_3:\;Pr^{3+}$ powders prepared by solid-state method with conventional mixing. $SrTiO_3:\;Pr^{3+}$ phosphor powders by Supercritical Fluid Mixing have spherical shapes and narrow particle size distribution. We have investigated the luminescent properties of $SrTiO_3:\;Pr^{3+}$ phosphor using $Al^{3+}$ and $Ga^{3+}$ as sensitizer.

• Journal of the Korean Ceramic Society
• /
• v.41 no.6
• /
• pp.481-484
• /
• 2004

TiO$_2$ and TiO$_2$-CdS powders which were expected to be highly activated photocatalysts were prepared using supercritical fluid method (SCF). The prepared photocatalyst TiO$_2$ powders were crystalline of anatase and ultrafine spherical powders with large specific surface area. When photodecompositoion reaction was done with TiO$_2$ powders prepared by SCF as a photocatalyst in DCA (Dichloroactic Acid) solution, a hazardous organic compound, the photocatlyst, properties of TiO$_2$ powders prepared by SCF were better than that of commercial TiO$_2$ powders.