Experimental and Theoretical Investigation of Supercritical Processes: Kinetics of Phase Transitions in Binary “2-Propanol—CO2” System (original) (raw)
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The Journal of Supercritical Fluids, 2013
Experimental phase equilibrium data for the systems CO 2 + n-dodecane, CO 2 + 1-decanol and CO 2 + 3,7-dimethyl-1-octanol were used to determine values for binary interaction parameters for use in the RK-ASPEN thermodynamic model in Aspen Plus ®. Bubble and dew point data of the mixtures CO 2 + (n-dodecane + 1-decanol), CO 2 + (n-dodecane + 3,7-dimethyl-1-octanol), CO 2 + (1decanol + 3,7-dimethyl-1-octanol) and CO 2 + (n-dodecane + 1-decanol + 3,7-dimethyl-1-octanol) were measured experimentally in a static synthetic view cell, and compared to the data predicted by the RK-ASPEN model. The model predicted the phase equilibrium data reasonably well in the low solute concentration region; significant deviation of model predictions from experimental data occurred in the mixture critical and high solute concentration regions due to the exclusion of solute-solute interaction parameters in the model. Distribution coefficients and separation factors were determined for the multicomponent mixture and separation of the alkane from the alcohol mixture with a supercritical fluid extraction process was found to be possible.
2018
In supercritical CO2 extraction process , there are two essential steps: the extraction step in the extractor where the SC-CO2 allows the solvent or extract removal from product structure and the separation step which consists of the separation of CO2-solvents or CO2-extract in a cascade of cyclone separators downstream the extractor. Cyclone separators are separation devices that use the centrifugal and gravity forces to remove liquid phase from flue gases. Two supercritical extraction processes are studied here: organogels supercritical drying for aerogels production and supercritical extraction of polar compounds from natural products. Concerning the first process, the organogel is prepared by an aminoacid-type organogelator with aromatic solvents such as tetralin or toluene. The experimental results showed a good solvent recovery rate in the case of tetralin, exceeding 90% but an unsatisfactory separation for toluene with a yield below 65%. In order to understand the experimenta...
Phase Behavior and Modeling of Supercritical Carbon Dioxide−Organic Acid Mixtures
Industrial & Engineering Chemistry Research, 2000
Pressure-composition isotherms are obtained for binary mixtures of carbon dioxide with formic acid, acetic acid, butyric acid, valeric acid, caproic acid, and caprylic acid at temperatures of 35.0-120.0°C and pressures up to 250 bar. The accuracy of the experimental apparatus was tested by comparing the measured phase equilibrium data of the carbon dioxide-acetic acid system at 40.0 and 60.0°C with those of Laugier et al. These six carbon dioxide-polar solute systems exhibit type I phase behavior, which is characterized by an uninterrupted critical mixture curve that has a maximum in pressure. In each system, the mixture critical point increases as the temperatures increases, and also the mixture critical pressure increases as the molecular weight increases. On the contrary, the carbon dioxide-formic acid system shows a higher mixture critical pressure compared with those of the other systems. The experimental data are modeled using both the statistical associating fluid theory (SAFT) and the Peng-Robinson (P-R) equation of state. The SAFT equation of state reasonably models the pressure-composition isotherms for these six systems only if two temperature-independent mixture parameters are used for each system. The P-R equation of state calculated the phase behavior with one or two temperature-independent mixture parameters.
Phase equilibrium in supercritical CO2 mixtures using a modified Kwak-Mansoori mixing rule
AIChE Journal, 2004
The mixing rules proposed by Kwak and Mansoori for the Peng-Robinson equation of state have been modified to describe vapor-liquid equilibrium in mixtures that contain supercritical CO 2 . Data in the literature for nine binary liquid-vapor systems containing supercritical CO 2 are used for testing the modified models. The systems studied were binary mixtures containing carbon dioxide with lauric acid, palmitic acid, oleic acid, linoleic acid, 1-octanol, 1-decanol, 2-methyl-1-pentanol, ␣-pinene, and limonene. The modifications studied included the introduction of a nonquadratic mixing rule proposed by one of the authors and a different interaction parameter for the volume constant of the equation of state. Compared to results in the literature, the Kwak-Mansoori combining rules and the proposed empirical modifications give lower deviations in correlating the solute concentration in the vapor phase, the most important variable for the design of supercritical extraction processes. Contrary to arguments found in the literature, it is also demonstrated that a severe test for an equation of state and its mixing rules is the correlation of the solute concentration in vapor-liquid mixtures.
The Effect of Fluid Flow Rate and Extraction Time in Supercritical Carbon Dioxide
2019
1 Centre of Lipid Engineering and Applied Research (CLEAR), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia 2 Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia 3 Department of Chemical Engineering, Universiti Teknologi Petronas, 32610 Bandar Sri Iskandar, Perak, Malaysia
Food and Bioproducts Processing, 2020
tDeodorizer distillates are waste by-product from vegetable oil industries. It has excellentpotential as a source of bioactive compounds. Therefore, the aim of this study was tomodel the thermodynamic phase equilibrium and optimize the supercritical CO2extractionprocesses for concentrating valuable minor components from rapeseed oil deodorizer dis-tillates (RODD). The extraction was done in a countercurrent extraction column at pressure(35−40 MPa), temperature (313 K) and solvent to feed mass ratio (S/F) of 5. The raw materialemployed was initially saponified. Investigating the extraction process, representing phaseequilibria behavior of the multicomponent oil-type material/CO2mixture and prediction thesteady-state efficiency of the extractor was done by using the Stryjek–Vera Peng–Robinsonequation of state as a thermodynamic model for the experimental bubble pressures andvapor compositions. The extraction of -sitosterol and vitamin E in the saponified RODD atpredicted conditions showed a recovery of 76 wt% with a purity of 60 wt% and a recoveryof 85 wt% with a purity of 75 wt% respectively. Furthermore, the use of a modified sampleincreased the phytosterol and tocopherol efficiency and purity. The absolute average relativedeviation between the theoretical and experimental was within the range of 1–12%, whichis considered as a good agreement. The coupling of thermodynamic modeling with experi-mental work offered an efficient and rapid tool for analyzing the viability of the supercriticalextraction.
Binary mixtures of supercritical carbon dioxide with methanol. A molecular dynamics simulation study
Chemical Physics Letters, 2003
Molecular dynamics simulations were performed on supercritical mixtures of MeOH in CO 2 with MeOH mole fractions in the range 0.0939-0.1173 at 323.15 K and pressure from 9.952 to 16.96 MPa. It is found that the EPM2 model of CO 2 with the J2 model of MeOH predicts the experimental pVT relationship of the fluid in this region quite good. Furthermore, the structural and hydrogen-bonding data obtained reveal the existence of MeOH type aggregates in the mixed fluid. The latter finding was found to be in agreement with conclusions from previous experimental studies on this system.
International Journal of Thermodynamics
Mutual solubilities of a mixture containing 80.52% ethanol and 19.48% octane were measured in a carbon dioxide solvent using a high-pressure type phase equilibrium apparatus at pressures up to 100 bar and at a temperature of 75°C. Experimental results showed that a considerable separation was not achieved in the ethanol-octane ratio investigated in this work. The experimental data were then compared with the theoretical data which were obtained from the regular solution equations. Regular solution theory was employed for each phase by applying activity coefficient expressions. The regular solution theory approach has been found to be encouraging for the prediction of solubility data (vapor phase data) and also showed that the interaction parameters were dependent on pressure.