Ternary Hydrocarbon Mixtures Research Articles

Modelling of the three phase LLV region for ternary hydrocarbon mixtures with the Soave-Redlich-Kwong equation of state

The prediction of the three phase liquid-liquid-vapour (L2L1V) region for the ternary mixtures ethane + propane + eicosane (C2 + C3 + C20) and methane + ethane + eicosane (C1 + C2 + C20) was performed using the Soave-Redlich-Kwong equation of state. A procedure for finding K- and L-points is presented. It is based on the solution of thermodynamic conditions for the K- and L-point using the Newton iteration technique with carefully chosen starting points. The calculations were performed with all binary interaction parameters set to zero and with binary interaction parameters fitted to vapour-liquid equilibrium data of the binary subsystems. In the latter case for all binary subsystems two adjustable parameters with classical mixing rules were used. The results obtained show only qualitative agreement with experimental data for both sets of interaction parameters.

Vapor-liquid equilibria of binary mixtures containing methyl tert-butyl ether (MTBE) and/or substitution hydrocarbons at 298.15 K and 313.15 K

An up-to-date high accuracy vapor-liquid equilibrium apparatus (Van Ness' type) for binary and ternary mixtures has been newly built and successfully tested. A program on thermodynamic characterization of binary and ternary mixtures of oxygenate additives and/or hydrocarbons substituting the main classes of constituents of a real gasoline is presented. Some of the early results are reported, discussed and compared with literature data. These systems are the binary mixtures cyclohexane + n-heptane, benzene + cyclohexane and methyl tert-buthyl ether (MTBE) + n-hexane, all have been measured at 313.15 K and the first of them at 298.15 K too.

Gravity drainage in a fissured reservoir with fluids not in equilibrium

If a matrix block in a fractured reservoir is surrounded by gas, the gravity forces tend to expel the oil from the matrix and the capillary forces tend to retain the oil. If the liquid and the gas are not at thermodynamic equilibrium, a lowering of the interfacial tension and a swelling of the liquid may improve the liquid recovery. Experiments performed with ternary mixtures of hydrocarbons (C 1− n C 4− n C 10) under simulated reservoir conditions show that the oil recovery by gravity drainage increases if the content of intermediate components in the gas or in the liquid phase increases. This phenomenon has been confirmed by numerical simulations using compositional models.

Viscosities of binary and ternary mixtures of polyaromatic hydrocarbons

Experimental measurements of the viscosities of the three binary-mixture combinations of the toluene/tetralin/1-methylnaphthalene system were performed over the entire concentration range for various temperatures ranging from 298 to 498 K. Viscosities were also determined for an equimolar mixture of the three components and for the binary naphthalene/tetralin system. Finally, the polar phenol/picoline mixture was found to have interesting associative properties. The viscosity data determined have an experimental uncertainty of 1.1%. The viscosity correlation of Mc Allister gave excellent representations of both binary and ternary data.

Prediction of excess molar enthalpies for ternary alcohol-saturated hydrocarbon mixtures

Binary excess molar enthalpies for alcohol-alcohol mixtures are well represented by use of the UNIQUAC associated-solution model, which includes two association constants for the dimerization and polymerization of pure alcohol molecules and one solvation constant between unlike alcohol molecules and takes account of non-polar interactions. The model is further extended to predict ternary excess enthalpies for mixtures containing two alcohols and one saturated hydrocarbon with only binary parameters. Calculated results agree with the published data of many mixtures.

Estimation of Soot Thresholds for Fuel Mixtures

Abstract Experimental soot threshold results obtained using binary and ternary hydrocarbon mixtures were analyzed to obtain two empirical rules for estimating the onset of soot formation for fuel blends in atmospheric pressure, laminar premixed and diffusion flames. The results suggest that the onset of soot formation for a fuel mixture of known composition can be accurately calculated from soot threshold data for the pure compounds.

Tricritical phenomena in ‘‘quasibinary’’ mixtures of hydrocarbons. I. Methane systems

Temperature, pressure, and composition measurements are reported for the three coexisting phases in the region of the tricritical points of two ternary mixtures of hydrocarbons: methane+n-pentane+2,3-dimethylbutane (I) and methane+2,2-dimethylbutane+2,3-dimethylbutane (II). These systems satisfy a ’’quasibinary’’ approximation in which the proportions of the two higher hydrocarbons [expressed as Z = xC/(xB+xC)] are the same in each of the three phases, so that the phase equilibrium is equivalent to that in a binary system with a solute of average properties. Least-squares analysis does not locate the tricritical point with high precision, but all the measurements are consistent with the predictions of the phenomenological theory that the exponents governing the approach to the tricritical point are the ’’classical’’ mean-field values. If, in accord with this view, we write the difference between the upper and lower critical-end-point temperatures (i.e., extent of the three-phase region) as Tu−Tl = B(Z−Zt)3/2, then the coordinates of the two tricritical points are (I) Zt = 0.28, Tt = 202.82 K, pt = 6.058 MPa and (II) Zt = 0.09, Tt = 201.60 K, pt = 5.938 MPa, xA = 0.965.

Indirect determination of concentrations in coexisting phases

A general method is reported for the determination of the compositions of existing phases in multicomponent mixtures. A previous study of tricritical phenoena in ternary mixtures of hydrocarbons is used to demonstrate the method of analysis.

Tricritical points in ternary mixtures of hydrocarbons

Tricritical points in ternary mixtures of hydrocarbons

Prediction of heats of mixing for ternary alcohols-saturated hydrocarbon mixtures

Ternary heat of mixing values for alcohol-alcoholsaturated hydrocarbon mixtures are successfully predicted by using an empirical equation based on the association model theory. Prediction is illustrated with 17 systems. Basic information necessary for prediction is the equilibrium constant of pure alcohol and one physical interaction parameter per binary pair. The enthalpy of a hydrogen bond formation is taken to be -6.0 kcal/mol, irrespective of alcohol species.

Thermodynamics of Ternary Alcohol-Saturated Hydrocarbon Mixtures

Thermodynamics of Ternary Alcohol-Saturated Hydrocarbon Mixtures

Study of the properties of binary and ternary mixtures of aromatic C8 hydrocarbons, n-nonane, and methanol

Study of the properties of binary and ternary mixtures of aromatic C8 hydrocarbons, n-nonane, and methanol

Solubility of Gaseous Hydrocarbon Mixtures in Water

Abstract At present no reliable theoretical or empirical method exists by which the solubility of gaseous hydrocarbon mixtures in water can be determined. Based on the experimental data of this work, an empirical correlation was developed by which solubility of gaseous hydrocarbon mixtures, using pure component solubilities, could be predicted. pure component solubilities, could be predicted. The effect of mixture composition on the solubility was also studied. Solubility of the following binary and tertiary hydrocarbon mixtures in water were experimentally determined as (1) methane-ethane mixtures at temperatures of 100 degrees to 220 degrees F and pressures of 700 to 8,000 psi; (2) methane-propane pressures of 700 to 8,000 psi; (2) methane-propane mixtures and ethane-propane mixtures at 220 degrees F and pressures of 700 to 8,000 psi; and (3) methane-ethane-propane mixtures at temperatures of 160 degrees to 220 degrees F and pressures of 700 to 5,000 psi. We found that: (1) the solubility of hydrocarbon mixtures increases with an increase in pressure and shows a minimum with an increase in temperature; (2) solubilities of the binary and ternary hydrocarbon mixtures are greater than the solubilities of the pure components at the same temperature and pressure; and (3) hydrocarbon-water solutions tested in this work show a positive deviation from Raoult's law. Introduction Quantitative information concerning the behavior of gaseous hydrocarbon-water mixtures under reservoir conditions is valuable to the petroleum and chemical industries. A thorough understanding of hydrocarbon-water systems A necessary because water is present in all steps of hydrocarbon gas handling processes. More experimental investigations have been reported for the formation of gas hydrates and gas water content than the determination of the solubility of hydrocarbon mixtures in water. Solubilities of pure light hydrocarbons and natural gas in water at various pressure and temperature ranges have been published. The information available concerning the solubility of binary hydrocarbon mixtures is fragmentary and data for ternary hydrocarbon mixtures are even more scant. The solubility of an ideal gas in an ideal solution, in equilibrium with each other, can be determined using Henry's law. At high pressures, both the gas and liquid will behave nonideally. The theories pertaining to solubility and the different kinds of nonideal solutions have been presented by Hildebrand and Scott. In analyzing presented by Hildebrand and Scott. In analyzing the solubility of hydrocarbons in water, Shinda and Fujihira state, "Enthalpy and entropy of solution of non-polar solutes in water diverge strikingly from the normal behavior established for regular solutions. This abnormality has been considered mostly due to the iceberg formation around solute molecules in water." There is no reliable method for predicting the solubility of a gaseous mixture in water, under nonideal conditions. This paper describes an experimental determination of the solubilities of gaseous hydrocarbon mixtures in water. Based on the experimental results, we developed an empirical correlation by which the solubility of hydrocarbon mixtures can be predicted. Results indicate that the solubility of the hydrocarbon mixture increase with an increase in pressure and show a minimum at around 160 degrees F. pressure and show a minimum at around 160 degrees F. Solubilities of the mixtures are greater than their pure constituents under the same conditions. pure constituents under the same conditions. Calculated values, using the empirical correlation developed in this work, compare well with the experimental data obtained by McKetta.

Interaction model for critical pressures of multicomponent methane-free aliphatic hydrocarbon mixtures

An interaction model has been proposed to represent the critical pressure of a multicomponent aliphatic hydrocarbon system not containing methane. This model has been expressed mathematically as an expansion which for its definition requires the establishment of interaction coefficients. For a proper representation of the critical pressure, this expansion has been truncated beyond the fourth order interactions. Experimental critical pressures available in the literature for multicomponent systems have been utilized to establish the second and third order interaction coefficients. Due to the lack of sufficient experimental critical pressures on quaternary systems, the fourth order interaction coefficient cannot be established at this time. Using the second and third order interaction coefficients, the critical pressures of 120 compositions of binary, ternary, quarternary, and quinary methane-free aliphatic hydrocarbon mixtures were calculated and were compared with corresponding experimental values to produce an average deviation of 3·25 per cent.

Generalized Correlations for Predicting Solubility, Swelling and Viscosity Behavior of CO2 -Crude Oil Systems

Abstract This paper presents correlations for predicting the solubility, swelling and viscosity behavior of CO2-crude oil systems. The correlations were developed from experimental data obtained by the authors. These data are also presented. The data were determined by measuring the properties of mixtures of CO2 and nine different oils. Experimental conditions covered a range of 100 to 250 degrees F and pressures up to 2,300 psia. Properties predicted by the correlations have average deviations, expressed as per cent of experimental value, of 2 per cent for solubility, 0.5 per cent for swelling and 12 per cent for viscosity. Introduction Interest in CO2 injection as an oil recovery process has led to the development of performance prediction methods which can be applied to specific reservoirs. To use these performance prediction methods, it is necessary to know the solubility, swelling, and viscosity properties of CO2-crude oil mixtures at reservoir conditions. Some information on these properties has appeared in the literature; however, this information did not cover the range of different oils and conditions needed to prepare generalized correlations for reservoir engineering purposes. Consequently, an experimental program was undertaken to collect the data needed. The data obtained and the correlations developed from the data are described in the following sections of this paper. SOLUBILITY OF CO2 IN CRUDE OILS CO2 solubility data in the literature come from six principal sources. The solubility prediction method of Welker and Dunlop is limited to 80F.The information in Ref. 4 is of two types: the first includes binary and ternary mixtures of CO2 and light hydrocarbons (C1 to C6), and the second gives data for CO2 and heavy hydrocarbons for a temperature range of 40 to 90F.Ref. 5 contains a KCO2 chart for systems whose convergence pressure is 4,000 psia. The KCO2's are based mainly on CO2-natural gas mixtures. Poettmann's work covered CO2 solubility in one condensate and one crude oil. Jacoby and Rzasa measured CO2 solubilities as a function of pressure and temperature for two natural gas-absorber oil mixtures and two natural gas-crude oil mixtures. CO2 concentration in these four systems was fixed at 5 mol per cent. The work reported in this paper extends CO2 solubility data to a variety of different crude oil types in a temperature range from 110 to 250F and pressures up to 2,300 psia. The experimental procedure used by the authors to obtain the solubility data consisted of combining known amounts of pure CO2 and crude oil in a visual cell at a fixed temperature and measuring the bubble point of the mixture. Measurements were made for a total of 40 different CO2-oil mixtures and the results are shown in Table 2. The mixtures included nine different oils (seven crude oils and two refined oils) whose properties are listed in Table 1. All nine oils had vapor pressures less than 1 atm at the experimental temperatures. Consequently, analysis of the bubble-point vapor showed a CO2 concentration over 99 mol per cent. At no time during these experiments was a second, more dense, liquid phase observed. The solubility correlation which was developed from the data in Table 2 is presented in Figs. 1, 2 and 3. In these figures, solubility is expressed as xCO2, the mol fraction of CO2 in the CO2-Oil mixture. Fig. 1 shows solubility as a function of CO2 fugacity and temperature. Fig. 2 shows the same solubility data expressed as a function of saturation pressure and temperature. The solubility shown in Figs. 1 and 2 is for an oil whose UOP characterization factor is 11.7. UOP characterization factors of crude oils can be determined from Ref. 10 if the viscosity and API gravity of the oil are known. Fig. 3 gives the solubility correction factor for oils whose UOP characterization factors differ from 11.7. JPT P. 102ˆ

Predictions of K-Values for Ternary Hydrocarbon Systems: Conditions up to the Critical Point

Abstract A method has been developed that permits the correlations of Mehra and Thodos and Dastur and Thodos for binary systems to be used for the prediction of the vapor-liquid equilibrium constants of the light and heavy constituent, Kl and Kh, of a ternary hydrocarbon mixture. Furthermore, the unique relationship observed in this study, i.e., a plot of log Kl/Ki vs log Kl/Kh is linear and passes through the origin, permits the calculation of the K-value for the intermediate component. This approach has been used to establish K-values for the constituents of the three ternary hydrocarbon systems used to develop this method and has also been applied to two additional ternary hydrocarbon systems to yield an average deviation of 7.7 per cent resulting from a total of 294 points for the five ternary systems considered. Introduction The rigorous calculation of vapor-liquid equilibrium constants for systems containing two or more components is a difficult problem and becomes extremely complex at elevated pressures and for conditions approaching critical point. Although thermodynamic relationships can be developed to account for the vapor-liquid equilibrium behavior of simple systems, their use is limited because the necessary PVT data for these systems are not generally available. To establish a method for calculating K constants directly, without any recourse to the PVT behavior of a system, Mehra and Thodos applied the principle of corresponding states to the vapor-liquid equilibrium constants of binary hydrocarbon systems. They developed a series of charts which made possible the prediction of K-values for all binary hydrocarbon systems not containing methane. This work has been extended by Dastur and Thodos to include binary hydrocarbon systems containing methane. The charts developed in these two studies cover the high-pressure region and are applicable to conditions in the vicinity of the critical point. The ability of this approach to predict vapor-liquid equilibrium constants of binary hydrocarbon systems suggests that this method may be extended to the prediction of the K-values of the components of ternary hydrocarbon systems. In this investigation, the charts developed for both the methane and non-methane binary systems, together with mixture rules developed in this study, have been used to predict the K- values of the light and heavy components of a ternary hydrocarbon system. These calculated values are then used to establish the K-value of the intermediate component through the use of a novel relationship developed in the present study. DEVELOPMENT OF METHOD FOR PREDICTING K-VALUES OF TERNARY SYSTEMS The application of the corresponding state charts developed for binary hydrocarbon systems is restricted to those systems containing two components. The extension of these correlations to three-component systems requires that the ternary system be reduced to an equivalent binary, which can be treated in a manner consistent with the corresponding state development. To establish such an approach, the vapor-liquid equilibrium constant of the light component Kl is first calculated by assuming that the ternary mixture consists of the light component and a pseudo- heavy component of the intermediate and heavy constituents of the original ternary. To establish the vapor-liquid equilibrium constant of the heavy component Kb, the light and intermediate constituents of the ternary are combined to form a pseudo-light component of another equivalent binary system. The calculated values Kl and Kb are then utilized to calculate the vapor-liquid equilibrium constant of the intermediate component Ki. SPEJ P. 329ˆ

Stability limits of flames of ternary hydrocarbon mixtures

Studies of lean blow-off and flash-back limits of laminar flames of ternary hydrocarbon mixtures containing ethylene show that these stability limits of the mixtures are predictable. The fuel components are non-interfering in flames at these limits. The contributions of the individual hydrocarbons are additive and define the limit of the mixture. However, at rich blow-off, there is evidence of inhibition in mixtures where ethylene is the primary fuel and in mixtures where the ethylene concentration exceeds a certain minimum as a secondary fuel. Consequently, the rich blow-off limits of mixtures containing ethylene are not usually predictable.