Solubility of Carbon Dioxide in Water and Hexadecane: Experimental Measurement and Thermodynamic Modeling (original) (raw)
Related papers
Injection of a soluble gas like CO2 into an oil reservoir reduces the interfacial tension and oil viscosity and contributes to oil swelling, which together, in turn, enhance the oil mobility and relative permeability. In this work an experimental phase equilibrium setup for the recombination of live oil (stock-tank oil and first-stage separator gas) and measurement of the corresponding phase behaviors of CO2/live oil mixtures is described. In the recombination process, the vapor-to-oil molar ratio was adjusted until the composition of the original reservoir fluid was obtained. The average of the absolute error (AAE) in composition was about 0.77% and 1.09% for the two reservoir fluids under test (named here wells A#22 and A#33, respectively). The optimum vapor-tooil molar ratio for zero deviation in the methane composition in the live oil (recombined) was about 0.42 for both wells. In addition, the PVTi simulator was used to reproduce the live oil (by combining the first-stage separator gas and the stock-tank oil) and also to predict the recombined oil characteristics at the reservoirs' saturation pressure and bottom hole temperature. On the other hand, the PVTpro simulator was used to investigate the oil swelling rate and establish the relationship between saturation pressure and the injected CO2 mass fraction. The average of the absolute relative error (AARE) between experimental and predicted saturation pressures was 7.78% for well A#22 and 5.38% for well A#33.
The Journal of Supercritical Fluids, 2016
The knowledge about crude oil phase behavior at high-pressures is a challenge for scientists due to inherent complexity to this systems. Some works employ model systems attempting to predict crude oil behavior, but the results are normally poor. In this sense, the use of real crude oil fractions can be an alternative to improve the accuracy of the models used in these simulations. In this work, a light oil sample has been fractionated to generate four representative fractions. An approach to estimate the critical properties of these distilled fractions using only density and vapor pressure experimental data is presented. In sequence, phase behavior of the pseudo binary (carbon dioxide (CO 2) + real crude oil fractions), multicomponent (mixture of fractions + CO 2) and original crude oil + CO 2 systems were determined using static synthetic method and static synthetic + NIR, with CO 2 molar fraction range of 0.367-0.986, temperature range of 20-80 • C and pressure up to 300 bar. Binary interaction parameters (BIP) were estimated for each pair (CO 2 + distilled fraction) and employed to describe the phase behavior of a CO 2 + crude oil systems with Peng-Robinson equation of state (PR-EOS) and quadratic mixing rule. The results suggest that the use of real fractions can be a safer strategy for predicting the phase behavior of petroleum in carbon dioxide. Besides, NIR spectroscopy showed to be a good alternative to study phase behavior of dark/opaque systems.
Phase Behavior of UAE Crude-Oil/Carbon Dioxide System at Reservoir Temperature
International Journal of Modern Sciences and Engineering Technology (IJMSET), 2014
A significant number of Enhanced Oil Recovery (EOR) techniques focus on increasing the displacement efficiency as their main recovery mechanism by injecting carbon dioxide.. Carbon dioxide flooding is among the most promise EOR methods for the light and medium oil reservoirs and has been successfully used in a number of worldwide basins. Carbon Dioxide becomes supercritical when injected under field conditions, and as a natural hydrocarbon solvent, it not only can recover more oil but also considerably reduces greenhouse gas emissions. Several factors affect the mobilization efficiency. These factors include rock geometry, pore structure, flooding rate and fluid properties. Phase behavior of the system is controlled by the properties of the reservoir oil and injected fluid mixture which depend on pressure, temperature, oil composition, and injected fluid composition. In this work, phase behavior data and swelling test at well temperature of UAE crude oil is presented. The static synthetic method is used to perform saturation pressure measurements at well temperature. Results show there is a critical carbon dioxide concentration above which a liquid-liquid-gas equilibrium is observed.
Journal of Chemical & Engineering Data, 2020
The solubility of carbon dioxide in organic solvents at high temperatures and pressures is required for certain enhanced oil recovery processes. In this study, the solubilities of CO 2 in two different solvents, ethyl benzoate and triethyl citrate, were measured at saturation conditions at temperatures ranging between 298.15 and 373.15 K. The solubility was determined by measuring the saturation pressure of CO 2 −solvent using the constant-mass expansion method. For each solvent, six mixtures were tested with CO 2 mole fractions varying between 0.65 and 0.90 with 0.05 increments. The results show each mixture's saturation pressure increasing virtually linearly with temperature. For ethyl benzoate, the saturation pressure varied between 5.38 MPa at 298.15 K for the 0.65 x CO 2 solution to 19.7 MPa at 373.15 K for the 0.90 x CO 2 solution. For triethyl citrate, the saturation pressure varied between 4.00 MPa at 298.15 K for the 0.65 x CO 2 solution to 22.4 MPa at 373.15 K for the 0.90 x CO 2 solution. The saturated solutions' x CO 2 values follow a simple exponential model in pressure and temperature. For both solvents, the saturation conditions predicted by the Peng−Robinson equation of state with adjusted parameters showed deviations, especially at higher temperatures and at larger CO 2 concentrations.
Solubility of Carbon Dioxide in Two Pentaerythritol Ester Oils between (283 and 333) K
Journal of Chemical & Engineering Data, 2008
In this work, the solubility of carbon dioxide, CO 2 , in pentaerythritol tetrapentanoate (PEC5) and in pentaerythritol tetra(2-ethylhexanoate) (PEBE8) has been performed from (283 to 333) K and pressures up to 7 MPa in a new high-pressure gas solubility apparatus. The results show that in the present analyzed range CO 2 is highly soluble in these oils and that the solubility expressed as CO 2 mole fraction is practically not dependent on the branching of the acid chain, whereas it increases slightly with the length of the PE acid chains in the present range of compositions. The gas solubility data were satisfactorily correlated with the Soave-Redlich-Kwong (SRK) equation of state (EOS) using the conventional quadratic mixing rule with two interaction parameters for each temperature.
Solubility of CO2 in some heavy alcohols and correlation of fluid phase equilibrium
Fluid Phase Equilibria, 2003
The synthetic method was applied to measure the phase equilibrium of binary mixtures involving CO 2 and the following alcohols: undecan-2-ol, undecan-6-ol, undec-10-en-1-ol, and 2-methylpentan-2,4-diol. Measurements were performed at three different temperatures: 313.15, 323.15, and 333.15 K. The bubble points were measured at carbon dioxide mole fractions between 0.1 and 0.8 and at a pressure range of 13-160 bar. The results were correlated with the Peng-Robinson equation of state using the quadratic mixing rules.
Experimental and Modeling Study of the Phase Behavior of (Heptane + Carbon Dioxide + Water) Mixtures
Journal of Chemical & Engineering Data, 2015
We report experimental measurements of three-phase equilibria in the system (heptane + carbon dioxide + water) obtained with a quasi-static analytical apparatus with compositional analysis by means of gas chromatography. The apparatus was calibrated by an absolute area method and the whole measurement system was validated by means of comparison with the published literature data of the system (heptane + carbon dioxide). The compositions of the three phases coexisting in equilibrium were measured along five isotherms at temperatures from (323.15 to 413.15) K with pressures ranging from approximately 2 MPa to the upper critical end point pressure at which the two non-aqueous phases became critical. The experimental results have been compared with the predictions of the statistical associating fluid theory for potentials of variable range. The unlike binary interaction parameters used here are consistent with a previous study for a ternary mixture of a different n-alkane, while the alkane-water binary interaction parameter is found to be transferable and the alkane-carbon dioxide binary interaction parameter is predicted using a modified Hudson-McCoubrey combining rule. Generally, good agreement between experiment and theory was found.
Low-pressure equilibrium data for the prediction of solubility in carbon dioxide
Chemical Engineering Science, 1990
A method is proposed for the Calculation of solubilities in compressed carbon dioxide. The method is illustrated with the hard-sphere equation of state, but the main feature is the use of low-pressure-low-temperature solubility data for determining the binary interaction parameters. Examples are reported for carbon dioxide because of its industrial use in supercritical fluid extraction.