Polymerization ofN-Vinylcarbazole in Supercritical Carbon Dioxide and in a Supercritical Region of a Carbon Dioxide and Dimethyl Ether Mixture

2008 ◽  
Vol 47 (15) ◽  
pp. 5734-5741 ◽  
Author(s):  
Kyoung Shil Oh ◽  
Won Bae ◽  
Youn-Woo Lee ◽  
Hwayong Kim
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Dimethyl Ether ◽  
Supercritical Region ◽  
Ether Mixture ◽  
Supercritical Carbon

scholarly journals Enhancement of Lipid Extraction from Soya Bean by Addition of Dimethyl Ether as Entrainer into Supercritical Carbon Dioxide

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1223
Author(s):  
Hideki Kanda ◽  
Yuji Fukuta ◽  
Wahyudiono ◽  
Motonobu Goto
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Dimethyl Ether ◽  
Neutral Lipids ◽  
Lipid Extraction ◽  
Operating Pressure ◽  
Supercritical Carbon Dioxide Extraction ◽  
Ether Extraction ◽  
Carbon Dioxide Extraction ◽  
Supercritical Carbon

Soya beans contain a variety of lipids, and it is important to selectively separate neutral lipids from other lipids. Supercritical carbon dioxide extraction has been used as an alternative to the selective separation of neutral lipids from soya beans, usually using non-polar hexane. However, supercritical carbon dioxide extraction has a high operating pressure of over 40 MPa. On the other hand, liquefied dimethyl ether extraction, which has attracted attention in recent years, requires an operating pressure of only 0.5 MPa, but there is concern about the possibility of an explosion during operation because it is a flammable liquefied gas. Therefore, this study aims to reduce the operating pressure by using a non-flammable solvent, supercritical carbon dioxide extraction mixed with liquefied dimethyl ether as an entrainer. The extraction rate and the amount of neutral lipids extracted increased with increasing amounts of added liquefied dimethyl ether. In the mixed solvent, the amount of neutral lipids extracted was higher at an operating pressure of 20 MPa than in pure supercritical carbon dioxide extraction at 40 MPa. The mixing of liquefied dimethyl ether with supercritical carbon dioxide allowed an improvement in the extraction of neutral lipids while remaining non-flammable.

Transient Natural Convection Heat Transfer to CO2 in the Supercritical Region

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
G. Janardhana Reddy ◽  
Hussain Basha ◽  
N. S. Venkata Narayanan
Keyword(s):  
Carbon Dioxide ◽  
Thermal Expansion ◽  
Equation Of State ◽  
Supercritical Carbon Dioxide ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Physical Parameters ◽  
Reduced Pressure ◽  
Supercritical Region ◽  
Supercritical Carbon

Present research paper investigates the transient laminar free convective supercritical carbon dioxide flow past a semi-infinite vertical cylinder using numerical methods. Two new thermodynamic models for the supercritical fluid (SCF) flow are considered. Based on these models, for supercritical carbon dioxide, two new equations for thermal expansion coefficient are obtained on the basis of Redlich–Kwong equation of state (RK-EOS) and Van der Waals equation of state (VW-EOS). Based on the calculated values of thermal expansion coefficient, it is shown that not only RK-EOS is closer to experimental values but also gives greater accuracy when compared to VW-EOS validating RK-EOS as suitable model for predicting natural convective properties of carbon dioxide under supercritical condition. The governing equations of SCF flow are solved numerically using Crank–Nicolson implicit finite difference scheme. Numerical simulations are performed for carbon dioxide in the region of its critical point. Results in subcritical, supercritical, and near-critical regions are shown graphically and discussed for different physical parameters. From the obtained numerical results, it is clear that the steady-state time increases for the increasing values of reduced temperature and reduced pressure for carbon dioxide in supercritical region.

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