共查询到20条相似文献,搜索用时 15 毫秒
1.
We report experimental measurements of the phase behavior of (CO2 + H2O + NaCl) and (CO2 + H2O + KCl) at temperatures from 323.15 K to 423.15 K, pressure up to 18.0 MPa, and molalities of 2.5 and 4.0 mol kg−1. The present study was made using an analytical apparatus and is the first in which coexisting vapor- and liquid-phase composition data are provided. The new measurements are compared with the available literature data for the solubility of CO2 in brines, many of which were measured with the synthetic method. Some literature data show large deviations from our results.The asymmetric (γ–φ) approach is used to model the phase behavior of the two systems, with the Peng–Robinson equation of state to describe the vapor phase, and the electrolyte NRTL solution model to describe the liquid phase. The model describes the mixtures in a way that preserves from our previous work on (CO2 + H2O) the values of the Henry's law constant and the partial molar volume of CO2 at infinite dilution Hou et al. [22]. The activity coefficients of CO2 in the aqueous phase are provided. Additionally, the correlation of Duan et al. [14] for the solubility of CO2 in brines is tested against our liquid-phase data. 相似文献
2.
《Journal of Industrial and Engineering Chemistry》2014,20(6):4163-4168
The (CO2 + 2-ethoxyethyl acetate) and (CO2 + 2-(2-ethoxyethoxy)ethyl acetate) systems at 313.2, 333.2, 353.2, 373.2 and 393.2 K as well as pressures up to 20.59 MPa have been investigated using variable-volume high pressure view cell by static-type. The solubility curve of 2-ethoxyethyl acetate and 2-(2-ethoxyethoxy)ethyl acetate in the (CO2 + 2-ethoxyethyl acetate) and (CO2 + 2-(2-ethoxyethoxy)ethyl acetate) systems increases as the temperature increases at a constant pressure. The (CO2 + 2-ethoxyethyl acetate) and (CO2 + 2-(2-ethoxyethoxy)ethyl acetate) systems exhibit type-I phase behavior. The experimental results for the (CO2 + 2-ethoxyethyl acetate) and (CO2 + 2-(2-ethoxyethoxy)ethyl acetate) systems correlate with the Peng–Robinson equation of state using a van der Waals one-fluid mixing rule including two adjustable parameters. The critical properties of 2-ethoxyethyl acetate and 2-(2-ethoxyethoxy)ethyl acetate are predicted with the Joback–Lyderson group contribution and Lee–Kesler method. 相似文献
3.
《The Journal of Supercritical Fluids》2010,54(1-3):165-173
Post-processing drug impregnation of commercially available polymer-based devices is a recent and attractive approach for the development of multifunctional biomedical devices and implants, drug release systems and tissue scaffolds. Therapeutic ophthalmic articles, such as drug-loaded contact lenses, are already known to improve ocular bioavailability in the treatment of several eye diseases, namely glaucoma, as well as to minimize undesired systemic side-effects. In this work, commercial silicone-based hydrogel contact lenses (Balafilcon A) were impregnated with two anti-glaucoma drugs (acetazolamide and timolol maleate) using a discontinuous supercritical solvent impregnation (SSI) methodology. Pressure and temperature, as well as impregnation time and depressurization rate, were kept constant (17 MPa, 40 °C, 90 min, 0.06 MPa/min, respectively) in order to evaluate the effects of nature and concentration of cosolvents (ethanol and water at 5, 10 and 15% molar) on the impregnation efficiencies and the properties of the contact lenses. Glass-transition temperature (DSC), oxygen permeability, contact angle, apparent morphological changes (SEM) and in vitro drug release kinetics were studied in detail. Results demonstrated the feasibility of preparing acetazolamide and timolol maleate impregnated therapeutic Balafilcon A contact lenses using CO2 + EtOH and CO2 + H2O solvent mixtures. Valuable information about how the nature and the composition of the employed solvent mixtures influence drug loading, drug release profiles and contact lenses physical and thermomechanical properties was obtained. 相似文献
4.
A combined treatment of high hydrostatic pressure (HHP) and dense phase carbon dioxide (DPCD) was investigated to inactivate pectin methylesterase (PME), peroxidase (POD) and polyphenol oxidase (PPO) in feijoa (Acca sellowiana) puree. The treatments were HHP (HHP); carbonation and HHP (HHPcarb); carbonation + addition of 8.5 mL CO2/g puree into the headspace of the package and HHP (HHPcarb + CO2). The different samples were treated at 300, 450 and 600 MPa, for 5 min.The residual POD and PPO activity decreased in the order HHP > HHPcarb > HHPcarb + CO2 at all pressures used. Treatments with HHP at 300 MPa increased POD activity to 140%. The residual PME activity of HHPcarb and HHPcarb + CO2 samples at 600 MPa (45–50%) was significantly (p < 0.05) lower than for HHP treatment (65%).The simultaneous application of HHP and DPCD seems to synergistically enhance the inactivation of the enzymes studied, the CO2 concentration being a key process factor. 相似文献
5.
Melting temperatures of organic solids are often depressed by high-pressure CO2 due to a dissolution of CO2 in the molten organic compounds. For thermodynamic analysis of the melting point depression, solubilities of CO2 in molten biphenyl and naphthalene were measured by near-infrared spectroscopy at various temperatures and pressures up to 20 MPa. Molarity of the organic component was determined from the 3νCH absorption band, and that of CO2 from the 2ν1 + ν3 band. Mole fraction of CO2 in the liquid phase was found to be an increasing function of the pressure up to 0.6 at 20 MPa and a weakly decreasing function of the temperature. The solubility data were used for modeling of the mixtures by the Peng–Robinson equation of state with a binary interaction parameter k12. Calculation of the solid–liquid–gas phase equilibrium for the model fluid qualitatively described a large decrease in the melting temperature with increasing pressure up to 10 MPa followed by a small change at higher pressures. The melting point change was interpreted by the two competing effects: hydrostatic pressure effect increases the melting point by ca. 8 °C at 20 MPa, whereas CO2 solubility effect reduces it by ca. 30 °C. Decomposition of the solubility effect into ideal and non-ideal mixing parts revealed that the non-ideality increases the melting point by more than 10 °C. 相似文献
6.
A polar version of the group contribution PC-SAFT equation of state (GC-PPC-SAFT; Tamouza et al., 2004; NguyenHuynh et al., 2008) combined with a method for correlation/prediction of binary interaction parameters kij (NguyenHuynh et al., 2008) is here applied to model vapor–liquid, liquid–liquid and vapor–liquid–liquid phase equilibria of CO2 + alkanol mixtures simultaneously.A cross-association interaction between CO2 and alkanol had to be taken into account to model/predict the mixtures equilibria accurately. The cross-association parameters were evaluated using the so-called CR1 mixing rules supported by ab initio computations.Extensive prediction tests on CO2 + alkanol mixtures involving linear and branched alkanols are carried out. The results obtained showed that in most cases, the correlation and prediction calculations are qualitatively and quantitatively satisfactory: the overall deviations on liquid phase and vapor phase are respectively ΔX = 3–4% and ΔY = 1–2%. 相似文献
7.
Present work investigated the potential of artificial neural network (ANN) model to correlate the bubble and dew points pressures of binary systems containing carbon dioxide (CO2) and hydrocarbon systems as functions of reduced temperature of non-CO2 compounds, critical pressure, acentric factor of non-CO2 compounds and CO2 composition. In this regards, five binary systems at the temperature and pressure ranges of 263.15–393.15 K at 0.18–12.06 MPa were used to examine the feasibility of cascade-forward back-propagation ANN model. In this regard, the collected experimental data were divided in to two different subsets namely training and testing subsets. The training subset was selected in a way that covers all the ranges of the experimental data and operating conditions. Then, the accuracy of the proposed ANN model was evaluated through a test data set not used in the training stage. The optimal configuration of the proposed model was obtained based on the error analysis including minimum average absolute relative deviation percent (AARD %) and the appropriate (close to one) correlation coefficient (R2) of test data set. The obtained results show that the optimum neural network architecture was able to predict the phase envelope of binary system containing CO2 with an acceptable level of accuracy of AARD % of 2.66 and R2 of 0.9950 within their experimental uncertainty. In addition, comparisons were done between the Peng–Robinson (PR) equation of state (EOS) and ANN model for three different binary systems including CO2 + 1-hexene, CO2 + n-Hexane, and CO2 + n-butane. Results show that developed optimal ANN model is more accurate compared to the PR EOS. 相似文献
8.
An original experimental set-up combining a FTIR (Fourier Transformed InfraRed) microscope with a high pressure cell has been built in order to analyze in situ and simultaneously the CO2 sorption and the polymer swelling of microscopic polymer samples, such as fibers, subjected to supercritical carbon dioxide. Thanks to this experimental set-up, we have determined as a function of the CO2 pressure (from 2 to 15 MPa) the CO2 sorption and the polymer swelling at T = 40 °C of four polymer samples, namely PEO (polyethylene oxide), PLLA (poly-l-lactide acid), PET (polyethylene terephtalate) and PP (polypropylene). The quantity of CO2 sorbed in all the studied polymers increases with pressure. PEO and PLLA display a significant level of CO2 sorption (20 and 25% respectively, at P = 15 MPa). However, we observe that a lower quantity of CO2 can be sorbed into PP and PET (7 and 8% respectively, at P = 15 MPa). Comparing their thermodynamic behaviors and their intrinsic properties, we emphasize that a high CO2 sorption can be reach if on one hand, the polymer is able to form specific interaction with CO2 in order to thermodynamically favor the presence of CO2 molecules inside the polymer and on the other, displays high chains mobility in the amorphous region. PLLA and PEO fulfilled these two requirements whereas only one property is fulfilled by PET (specific interaction with CO2) and PP (high chains mobility). Finally, we have found that for a given CO2 sorption, the resulting swelling of the polymer depends mainly on its crystallinity. 相似文献
9.
Experimental phase equilibrium data for the systems CO2 + n-dodecane, CO2 + 1-decanol and CO2 + 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 CO2 + (n-dodecane + 1-decanol), CO2 + (n-dodecane + 3,7-dimethyl-1-octanol), CO2 + (1-decanol + 3,7-dimethyl-1-octanol) and CO2 + (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 multi-component mixture and separation of the alkane from the alcohol mixture with a supercritical fluid extraction process was found to be possible. 相似文献
10.
We have conducted experiments to obtain cloud-point data of binary and ternary mixtures for poly(isobornyl acrylate) [P(IBnA)] (Mw = 100,000) + isobornyl acrylate(IBnA) in supercritical carbon dioxide (CO2), P(IBnA) (Mw = 100,000) + dimethyl ether (DME) in CO2, P(IBnA) (Mw = 100,000) in propane and butane, and P(IBnA) (Mw = 1,000,000) in propane, propylene, butane and 1-butene at high pressure conditions. Phase behaviors for these systems were measured at a temperature range from 323.4 K to 474.1 K and pressure up to 296.7 MPa. The cloud-point curves of P(IBnA) (Mw = 100,000) + IBnA and DME in CO2 change from upper critical solution temperature (UCST) behavior to lower critical solution temperature (LCST) behavior as IBnA and DME concentration increases, and liquid–liquid–vapor phase behavior appears for the P(IBnA) (Mw = 100,000) + CO2 + 80.3 wt.% IBnA system. Phase behaviors of P(IBnA) and 50 wt.% IBnA in CO2 and P(IBnA) in propane and butane show the pressure difference in accordance with Mw = 1,000,000 and Mw = 100,000 of P(IBnA). Also, the solubility curves for IBnA in supercritical CO2 were measured at a temperature range of (313.2–393.2) K and pressure up to 22.86 MPa. The experimental results were modeled with the Peng–Robinson equation of state (PR-EOS) using a mixing rule including two adjustable parameters. The critical property of IBnA is estimated with the Joback–Lyderson method. 相似文献
11.
A setup based on a static visual synthetic method for determining phase equilibria up to 100 MPa is presented. Solubilities of carbon dioxide (CO2) in a high-oleic sunflower oil (HOSO) and in an additivated vegetable lubricant (BIO-2T-05) were determined from 298 K to 363 K up to CO2 mass compositions of 0.42. The experimental device was verified comparing the solubilities of CO2 in HOSO with values from other laboratory. For both systems, the values of CO2 solubility show cross-over pressures among the different isotherms. A new equation was used to correlate the solubility data, with deviations in CO2 mole fraction in the oil-rich phase lower than 1.6%. The prediction ability of Carvalho and Coutinho equation was tested with experimental data. Vapor–liquid–liquid equilibria were also investigated for CO2 + BIO-2T-05 in the range 288–305 K. Furthermore, densities and viscosities at 0.1 MPa for BIO-2T-05 were measured from 278 K to 373 K. 相似文献
12.
《The Journal of Supercritical Fluids》2007,39(3):306-311
This contribution reports new experimental data on vapor–liquid equilibrium of the binary system diallyl sulfide + carbon dioxide, at temperatures between 275 and 370 K and pressures up to 12 MPa. These data are of interest to study the extraction of Allium oils from garlic and onion, using near-critical CO2. The experimental data were modeled with a group-contribution equation of state. A (CH2S) functional group has been defined to represent alkyl and allyl sulfides. Pure group and binary interaction parameters for this new functional group have been determined. Good correlation and prediction of phase equilibrium conditions were obtained. 相似文献
13.
Density of CO2 saturated solutions of polyethylene glycols (PEGs) of different molecular weight was measured in pressure range from 8.0 MPa up to 47.7 MPa at a temperature of 343 K by a volumetric method. To validate the method density of pure CO2 was measured at different pressures and a temperature of 293 K. The results were compared to the literature data and the accuracy was better than 2%. The density was between 1.17 g/mL for PEG 1000/CO2 at 14.5 MPa and 1.78 g/mL for the system PEG 4000/CO2 at 35 MPa. Further, the data were compared to results, obtained by a gravimetric method using magnetic suspension balance (MSB).Viscosity of CO2 saturated solutions of polyethylene glycols (PEGs) of different molecular weight at different pressures and at a temperature of 343 K was measured using a high pressure view cell. Also a temperature impact on the viscosity of pure PEGs was observed at ambient pressure. After saturating PEG 1500 with 10 MPa of CO2 pressure its viscosity decreases from 76.6 mPa s to 2.24 mPa s at 333 K. Further addition of CO2 and increasing the pressure results in even lower viscosity and the highest viscosity reduction was reached at the highest pressure; at 35 MPa viscosity of the system PEG 1500/CO2 is only 0.665 mPa s. 相似文献
14.
《The Journal of Supercritical Fluids》2007,42(3):482-491
Cloud-point data are reported for poly(isopropyl acrylate) [P(IPA)] in CO2, propane, propylene, butane, 1-butene, and dimethyl ether (DME) and for poly(isopropyl methacrylate) [P(IPMA)] in CO2. P(IPA) + alkene cloud-point curves are ∼100 °C lower than the P(IPA) + alkane curves, which are close to the P(IPA) + CO2 curve located at temperatures greater than 130 °C and pressures of 2500 bar. P(IPA) dissolves in pure DME at conditions as mild as 50 °C and 200 bar. Since IPA and IPMA monomers are used as cosolvents with CO2, binary IPA + CO2 and IPMA + CO2 data are reported to complement the ternary cloud-point data. Both monomer + CO2 mixtures exhibit type-I behavior and both are adequately modeled with the Peng–Robinson equation of state. IPMA is a more effective cosolvent than IPA. The polymer + CO2 + monomer phase behavior suggests that it is viable to polymerize IPA or IPMA in CO2 at moderate operating conditions. 相似文献
15.
Volumetric properties of ionic liquids from cubic equation of state: Application to pure and mixture
S.M. Hosseini M.M. Alavianmehr D. Mohammad-Aghaie F. Fadaei-Nobandegani J. Moghadasi 《Journal of Industrial and Engineering Chemistry》2013,19(3):769-775
In this work, we developed a cubic equation of state (CEOS) for modeling the volumetric properties of various ionic liquids (ILs). Two temperature-dependent parameters presented in the CEOS, have been determined from two sets of corresponding states correlations which are based on the critical point data or the surface tension of ILs. The predicted densities of pure ILs were compared with the experimental data over a broad pressure range from 1 to 100 MPa. The total average absolute deviations (AADs) of the calculated densities of 948 data points from the experimental data are 1.82% using the critical property and 0.96% using the surface tension and liquid density as scaling parameters. Furthermore, the proposed CEOS was successfully extended to mixtures including IL + IL and IL + solvent systems. 1282 literature data points for mixtures were taken to check the reliability of the mixture version of the proposed CEOS. The AAD of the calculated densities of the mixtures using the surface tension and liquid density as scaling parameter is 0.37%. Furthermore, the excess molar volumes (VE) of the studied binary mixtures have been successfully computed by the use of the proposed CEOS. 相似文献
16.
《Chemical Engineering Research and Design》2014,92(12):2806-2813
Equilibrium solubility of m-nitroaniline and p-nitroaniline in supercritical carbon dioxide (SCCO2) is essential to design the process of SCCO2 extraction and to investigate the effect of each solute on the solubility in SCCO2 ternary system. However, the solubility data is not reported so far. We performed the solubility measurements at the temperatures of 308–328 K and in the pressure range of 11.0–21.0 MPa. The experimental results showed the solubility of m-nitroaniline and p-nitroaniline was enhanced in m-nitroaniline + p-nitroaniline + SCCO2 ternary system. The improvement factor (i), separation factor (μ) and separation efficiency (HE) in the ternary system were defined and calculated, and the best separation result could be obtained at 21.0 MPa and 328 K using SCCO2 extraction, where the separation efficiency was up to 90.9%. Based on the chemical association theory, a new model was developed to calculate the solubility of mixed solutes in SCCO2. The correlation result of the new model was tested by about 500 solubility data from 15 kinds of two solutes mixtures in SCCO2. The correlated result showed that the new model could achieve much better AARD (%) than those of frequently used Sovova and Sovova-T models. 相似文献
17.
Experimental studies of adiabatic flat and cellular premixed flames of (CH4 + H2) + (O2 + CO2) are presented. The hydrogen content in the fuel was varied from 0% to 35% and the oxygen content in the oxidizer was 31.55%. These mixtures could be formed when oxy-fuel combustion technology is combined with hydrogen enrichment. Non-stretched flames were stabilized at atmospheric pressure on a perforated plate burner. A heat flux method was used to determine propagation speeds under conditions when the net heat loss of the flame is zero. Adiabatic burning velocities of methane + hydrogen + carbon dioxide + oxygen mixtures were found in satisfactory agreement with the detailed kinetic modeling employing the Konnov mechanism. Under specific experimental conditions the flames become cellular; this leads to significant modification of the flame propagation speed. The onset of cellularity was observed throughout the stoichiometric range of the mixtures studied. Visual and photographic observations of the flames were performed to quantify their cellular structure. The results obtained in the present work in (CH4 + H2) + O2 + CO2 mixtures are in good accordance with the previous observations for different fuels, CH4, C2H6 and C3H8. The enrichment by hydrogen leads to: the increase of the laminar burning velocities; the increase of the number of cells observed; the decrease of the mean cell diameter. The flame acceleration due to cellularity was not affected by the hydrogen enrichment. 相似文献
18.
The frequency response of ferromagnetic nickel microcantilevers with lengths ranging between 200 μm and 400 μm immersed in gaseous, liquid and supercritical carbon dioxide (CO2) was investigated. The resonant frequency and the quality factor of the cantilever oscillations in CO2 were measured for each cantilever length in the temperature range between 298 K and 323 K and the pressure range between 0.1 MPa and 20.7 MPa. At a constant temperature, both the resonant frequency and the quality factor were found to decrease with increasing pressure as a result of the increasing CO2 density and viscosity. Very good agreement was found between the measured cantilever resonant frequencies and predictions of a model based on simplified hydrodynamic function of a cantilever oscillating harmonically in a viscous fluid valid for Reynolds numbers in the range of [1;1000] (average deviation of 2.40%). At high pressures of CO2, the experimental Q-factors agreed well with the predicted ones. At low CO2 pressures, additional internal mechanisms of the cantilever oscillation damping caused lowering of the measured Q-factor with respect to the hydrodynamic model predictions. 相似文献
19.
The mechanism of the CO + NO reaction catalyzed by Pt/SBA-15 was studied via independent investigations of CO oxidation and NO disproportionation. Below 400 °C, both CO + O2 and CO + NO reactions approach 100 % conversion, while the catalyst shows negligible activity for NO disproportionation. These results suggest that CO oxidation by atomic oxygen arising from NO dissociation is not a major route for CO2 formation in the CO + NO reaction. In situ IR spectra reveal the formation of isocyanates (NCO−) adsorbed on silica. Their surface concentration changes with the extent of the CO + NO reaction. A mechanism is proposed in which isocyanates are reaction intermediates. 相似文献
20.
The high-pressure vapour–liquid phase equilibria (P–T–x–y) of the binary mixture propylene glycol/CO2 have been experimentally investigated at temperatures of (398.2, 423.2 and 453.2) K over the pressure range from (2.5 to 55.0) MPa using a static-analytic method. Furthermore, the high-pressure vapour–liquid phase equilibria (P–T–x–y) of the ternary mixture propylene glycol/CO2/ethanol at constant temperatures of (398.2, 423.2 and 453.2) K and at constant pressure of 15.0 MPa have been determined using a static-analytic method. Initial concentrations of components in propylene glycol (PG)/ethanol (EtOH) mixture vary from 10 up to 90 wt.%. In general, for binary system it was observed that the solubility of CO2 in the heavy propylene glycol reach phase increases with increasing pressure at constant temperature. On the contrary, the composition of gaseous phase is not influenced by the pressure or the temperature. On average the solubility of PG in light phase of CO2 amounts to 30 wt.%. The system behaviour at temperature of 398.2 K was investigated up to 70.0 MPa and a single-phase region was not observed. Above the pressure 60.0 MPa a single-phase region of the system was observed for the temperature of 423.2 K. For the temperature of 453.2 K the single-phase was observed above the pressure of 48.0 MPa. For ternary system it was observed that the composition of heavy phase is slightly influenced by the temperature when the mass fraction of EtOH in initial mixture is higher than 50 wt.%. If the mass fraction of PG in initial mixture is higher than 50 wt.%, the composition of heavy phase is not influenced by the temperature anymore. The composition of the PG, EtOH and CO2 in light phase remains more or less unchanged and it is not influenced by the conditions. 相似文献