Set Of Binary Interaction Parameters Research Articles

Phase behavior of supercritical CO2 + nonionic ethoxylated surfactants + methanol: Experimental data and modeling with PC-SAFT equation of state

The use of surfactants for oil and gas purposes has been explored and extensively applied. However, such systems' thermodynamic and predictability behavior still needs further investigation. This work aims to describe the phase behavior of the systems composed of nonionic ethoxylated surfactants (nonylphenyl ethoxylated surfactants—IGEPAL CO-630 and CO-720) + carbon dioxide (CO2) with additional methanol in wide ranges of temperature (T = 313 to 413 K), pressure (P = 0.8 to 54.8 MPa), and CO2 molar compositions (up to 90.0 %). It was observed for all systems studied that CO2 solubility was inversely proportional to temperature and the number of ethoxylated units for pure surfactants. The addition of methanol greatly increases the overall CO2 solubility. The thermodynamic modeling through the PC-SAFT equation of state was also evaluated. Bubble pressure deviations of 13.63 % and 13.49 % were obtained for pure IGEPAL CO-630 and IGEPAL CO-720 + CO2, respectively, and 12.63 % for the ternary system (IGEPAL CO-720 + methanol + CO2). A new set of binary interaction parameters was also provided for IGEPAL CO-630 and IGEPAL CO-720 + CO2.

Modelling low pressure LLE and VLE of methanol/alkane mixtures with a modified Peng-Robinson EoS and the Huron-Vidal mixing rules

In this work, it is assessed the capabilities and limitations of a simple cubic EoS/GE thermodynamic model to describe the phase equilibria of methanol/alkane mixtures using generalized binary interaction parameters. In first place, the critical properties of the n-alkanes were selected to generalize the parameters of the model by fitting the liquid-liquid equilibria (LLE) of binary mixtures formed by methanol with pentane, heptane and decane respectively. Adequate description of the LLE coexistence curve can be obtained at atmospheric pressure for mixtures with n-alkanes in the 4-10 carbon number range. Also, it is possible to represent the mathematical behavior of the UCST of the methanol alkane series according to literature. Finally, some predictions were made for vapor liquid equilibria (VLE) and vapor-liquid-liquid equilibria (VLLE) conditions at low and high pressure. In general, predictions are unsatisfactory. In some cases, at low pressures, qualitative predictions for the azeotropic behavior can be obtained. In second place, a second set of generalized parameters were obtained by fitting the VLE of binary mixtures formed by methanol with propane, pentane and hexane. Using this new set, the model is capable to reproduce in qualitative way the high-pressure vapor-liquid equilibria of methanol/alkane mixtures between propane and decane. However, for LLE equilibria the results are inadequate from qualitative and quantitative points of view. Based on the results found in this work, it can be established that the selected model is not capable to describe simultaneously the VLE and LLE of methanol/alkane type mixtures reasonably with a single set of binary interaction parameters.

The Effect of Functional Groups on the Phase Behavior of Carbon Dioxide Binaries and Their Role in CCS.

In recent years we have focused our efforts on investigating various binary mixtures containing carbon dioxide to find the best candidate for CO2 capture and, therefore, for applications in the field of CCS and CCUS technologies. Continuing this project, the present study investigates the phase behavior of three binary systems containing carbon dioxide and different oxygenated compounds. Two thermodynamic models are examined for their ability to predict the phase behavior of these systems. The selected models are the well-known Peng–Robinson (PR) equation of state and the General Equation of State (GEOS), which is a generalization for all cubic equations of state with two, three, and four parameters, coupled with classical van der Waals mixing rules (two-parameter conventional mixing rule, 2PCMR). The carbon dioxide + ethyl acetate, carbon dioxide + 1,4-dioxane, and carbon dioxide + 1,2-dimethoxyethane binary systems were analyzed based on GEOS and PR equation of state models. The modeling approach is entirely predictive. Previously, it was proved that this approach was successful for members of the same homologous series. Unique sets of binary interaction parameters for each equation of state, determined for the carbon dioxide + 2-butanol binary model system, based on k12–l12 method, were used to examine the three systems. It was shown that the models predict that CO2 solubility in the three substances increases globally in the order 1,4-dioxane, 1,2-dimethoxyethane, and ethyl acetate. CO2 solubility in 1,2-dimethoxyethane, 1.4-dioxane, and ethyl acetate reduces with increasing temperature for the same pressure, and increases with lowering temperature for the same pressure, indicating a physical dissolving process of CO2 in all three substances. However, CO2 solubility for the carbon dioxide + ether systems (1,4-dioxane, 1,2-dimethoxyethane) is better at low temperatures and pressures, and decreases with increasing pressures, leading to higher critical points for the mixtures. By contrast, the solubility of ethyl acetate in carbon dioxide is less dependent on temperatures and pressures, and the mixture has lower pressures critical points. In other words, the ethers offer better solubilization at low pressures; however, the ester has better overall miscibility in terms of lower critical pressures. Among the binary systems investigated, the 1,2-dimethoxyethane is the best solvent for CO2 absorption.

Estimation of Solubility of BTEX, Light Hydrocarbons and Sour Gases in Triethylene Glycol Using the SAFT Equation of State

An accurate prediction of the absorption and desorption of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) is important for the estimation of BTEX emissions from glycol units in natural gas processing plants. This work presents an approach to accurately model the solubilities of BTEX in triethylene glycol (TEG). The absorption of gases studied in this work into TEG is physical in nature, and therefore is treated as physisorption in modeling. The Huang-Radosz version of Statistical Associating Fluid Theory (SAFT-HR) Equation of State (EoS) was utilized to estimate the solubilities of BTEX in TEG. A new set of SAFT parameters for TEG, as well as a new set of binary interaction parameters between TEG and other components were obtained by fitting experimental vapor pressure and liquid density of TEG and available experimental binary VLE data, respectively. Using these parameters, solubility of multicomponent gases in TEG are accurately predicted. To have an estimate of the relative accuracy of SAFT-HR EoS, the results from Perturbed–Chain SAFT (PC–SAFT) and Peng–Robinson (PR) EoS are also reported. The overall average of root–mean–square deviation (RMSD) for binary and ternary systems studied in this work, using SAFT-HR, PC–SAFT, and PR EoS obtained equal to 0.12, 0.20, and 1.56, respectively.

Phase Equilibrium Measurements and Thermodynamic Modeling of the Systems (CO2 + Ethyl Levulinate) and (CO2 + Levulinic Acid)

This work reports phase equilibrium measurements and thermodynamic modeling of the binary systems (CO2 + ethyl levulinate) and (CO2 + levulinic acid). Each composition was carried out in a high-pressure variable-volume view cell at temperatures ranging from 303.15 to 353.15 K and with CO2 mole fraction ranging from 0.4002 to 0.9751 for the system (CO2 + ethyl levulinate) and from 0.4083 to 0.9930 for the system (CO2 + levulinic acid). Under these conditions, only vapor–liquid phase transitions were observed. The experimental data were modeled with the Peng–Robinson cubic equation of state with the Boston–Mathias alpha function (PR-BM) and using the van der Waals quadratic mixing rule. The results showed that the experimental data of the system (CO2 + ethyl levulinate) were adequately represented by the thermodynamic model with a unique set of binary interaction parameters, which were fitted from all isotherms. Whereas the experimental data of the system (CO2 + levulinic acid) were only adequately represen...

Phase Behavior of Heavy-Oil/Propane Mixtures

Summary The phase behavior of heavy-oil/propane mixtures was mapped from temperatures ranging from 20 to 180°C and pressures up to 10 MPa. Both vapor/liquid (VL1) and liquid/liquid (L1L2) regions were observed. Saturation pressures (VL1 boundary) were measured in a Jefri 100-cm3 pressure/volume/temperature (PVT) -cell and blind-cell apparatus. The propane content at which a light propane-rich phase and a heavy bitumen-rich (or pitch) phase formed (L1/L1L2 boundary) was visually determined with a high-pressure microscope (HPM) while titrating propane into the bitumen. High-pressure and high-temperature yield data were measured using a blind-cell apparatus. Here, yield is defined as the mass of the indicated component(s) in the pitch phase divided by the mass of bitumen in the feed. A procedure was developed and used to measure propane-rich-phase and pitch-phase compositions in a PVT cell. Pressure/temperature and pressure/composition phase diagrams were constructed from the saturation-pressure and pitch-phase-onset data. High-pressure micrographs demonstrated that, at lower temperatures and propane contents, the pitch phase appeared as glassy particles, whereas at higher propane contents and temperatures, it appeared as a liquid phase. Ternary diagrams were also constructed to present phase-composition data. The ability of a volume-translated Peng-Robinson cubic equation of state (CEOS) (Peng and Robinson 1976) to match the experimental measurements was explored. Two sets of binary-interaction parameters were tested: temperature-dependent binary-interaction parameters (SvdW) and composition-dependent binary-interaction parameters (CDvdW). Models derived from both types of binary-interaction parameters matched the saturation pressures and the L1L2 boundaries at one pressure but could not match the pressure dependency of the L1L2 boundary or the measured L1L2 phase compositions. The SvdW model could not match the yield data, whereas the CDvdW model matched yields at temperatures up to 90°C.

Review and Thermodynamic Modeling with NRTL Model of Vapor–Liquid Equilibria (VLE) of Aroma Compounds Highly Diluted in Ethanol–Water Mixtures at 101.3 kPa

A review of the vapor–liquid equilibrium data of aroma compounds highly diluted in hydroalcoholic mixtures at 101.3 kPa is presented. The study includes 44 aroma compounds present in distilled beverages from seven chemical families: acetals, alcohols, carbonyl compounds, carboxylic acids, esters, furans, and terpenes. The equilibrium data are modeled using the ideal gas hypothesis (with a correction term for dimerization in the case of carboxylic acids) and the NRTL model. A set of binary interaction parameters is generated, and the quality of the representation is evaluated. A classification of the aroma compounds in terms of their relative volatility with respect to ethanol and water is proposed over the whole ethanol composition range in the liquid phase. Finally, a comparison with the representation obtained when using interaction parameters calculated from binary and ternary mixture data at high concentrations is performed in order to evaluate the extrapolation capability of the NRTL model.

New Method Based on the UNIFAC–VISCO Model for the Estimation of Ionic Liquids Viscosity Using the Experimental Data Recommended by Mathematical Gnostics

The viscosity of ionic liquids (ILs) has been modeled as a function of temperature and at atmospheric pressure using a new method based on the UNIFAC–VISCO method. This model extends the calculations previously reported by our group (see Zhao et al. J. Chem. Eng. Data 2016, 61, 2160–2169) which used 154 experimental viscosity data points of 25 ionic liquids for regression of a set of binary interaction parameters and ion Vogel–Fulcher–Tammann (VFT) parameters. Discrepancies in the experimental data of the same IL affect the quality of the correlation and thus the development of the predictive method. In this work, mathematical gnostics was used to analyze the experimental data from different sources and recommend one set of reliable data for each IL. These recommended data (totally 819 data points) for 70 ILs were correlated using this model to obtain an extended set of binary interaction parameters and ion VFT parameters, with a regression accuracy of 1.4%. In addition, 966 experimental viscosity data po...

Water content of light n‐alkanes: New measurements and cubic‐plus‐association equation of state modeling

Light hydrocarbon gases such as methane, ethane, propane, and butane or other so called gaseous solvents have been suggested as steam additives to improve bitumen recovery and energy efficiency. The water content of these gases is one of the key requirements in the simulation and design of solvent‐aided thermal heavy oil recovery processes. In this work, we present new experimental data for the water content of these gases at high temperatures (up to 493.15 K) and moderate pressures (P < 6 MPa). The experimental data was regenerated using the cubic‐plus‐association equation of state. The Soave–Redlich–Kwong equation of state is used to treat the physical interactions. The association interactions are captured using Wertheim's first‐order thermodynamic perturbation theory. A set of binary interaction parameters is proposed to calculate the water content of methane, ethane, propane, and n‐butane at the operating conditions of the thermal heavy oil and bitumen recovery processes. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1384–1389, 2017

Characterisation of organic solvent nanofiltration membranes in multi-component mixtures: Phenomena-based modelling and membrane modelling maps

Organic solvent nanofiltration (OSN) is a promising, energy saving membrane separation technology for the purification and separation of organic liquids. Challenges for process design include the selection of a suitable membrane and a suitable solvent (mixture) in the process. To solve these challenges, decisions are currently taken based on costly and time-consuming OSN membrane screening experiments. Besides the large associated experimental effort, they often fail to identify the best suitable combination of OSN membrane and solvent (mixture) due to their non-targeted nature. Therefore, modelling of the underlying permeation mechanism to predict solvent fluxes/solute rejections and, more important, to generate insight into the transport, is recommended. In this paper, a phenomena-based model for multi-component permeation through polymeric OSN membranes based on solution–diffusion, pore-flow and mutual coupling terms is presented. Instead of developing a very detailed model, the objective of the model is to attain a fixed set of binary interaction parameters for a given OSN membrane, solvents and solutes in analogy to vapour–liquid equilibria (VLE) parameter sets. Moreover, the processing of insights gained by the model is demonstrated, leading to a suggestion for a separation improvement, either being focused on the membrane or on the applied solvent (mixture). As a conceptual graphical tool, membrane modelling maps (MMM) are introduced. MMM highlight the shares of the permeation phenomena and give recommendations for rejection improvement in dependence of the solute and the applied solvent (mixture). As an experimental basis for parameter estimation and model evaluation, permeability and rejection data in binary and ternary mixtures of toluene, n-hexane and 2-propanol for Starmem™122 from a previous publication is used.

Liquid–liquid equilibrium of pseudoternary systems containing glycerol + ethanol + ethylic biodiesel from crambe oil (Crambe abyssinica) at T/K = (298.2, 318.2, 338.2) and thermodynamic modeling

In the present work liquid–liquid equilibrium (LLE) data were obtained for systems composed of glycerol+ethanol+distilled fatty acid ethyl esters from crambe oil at T/K=298.2, 318.2 and 338.2. The experimental data measured for these systems were used to adjust the binary interaction parameters between their components for NRTL model treating the mixture of ester as a single ethyl ester, with the average molar mass of the mixture of esters. Two sets of UNIFAC binary interaction parameters were also tested to predict the LLE of the systems. Ethanol, which is distributed in the glycerol-rich and ester-rich phases, showed a greater affinity to the glycerol rich phase. Glycerol and FAEE presented very low miscibility. The average deviations related to mass fraction composition between experimental and calculated values by the NRTL model were less than 0.82% and by the UNIFAC model were between 2.27% and 3.97%, considering the two different sets of binary interaction parameters.

PVTx properties of H 2O–H 2S fluid mixtures at elevated temperature and pressure based on new experimental data

The volumetric properties of H 2O–H 2S fluid mixtures have been determined experimentally at temperatures of 150 to 400 °C and pressures up to 240 bar. Using these data and existing equations of state, we have developed a thermodynamic model for H 2O–H 2S fluid mixtures. This model is based on an asymmetric description of phases, which includes an activity model and a P–T-dependent Henry’s law constant for the liquid, and equations of state with mixing rules for the vapour. The fugacity of the vapour was calculated using the cubic equations of state of Peng and Robinson (1976) and Patel and Teja (1982) with density-dependent and composition-dependent mixing rules. Sets of binary interaction parameters for these equations were fitted to the experimental data obtained in this study supplemented by high-temperature PVTx data for H 2O–H 2S fluid mixtures reported in the literature. The Peng–Robinson equation used in conjunction with density-dependent mixing rules was found to be the most accurate of the available equations in representing the properties of the vapour phase. The errors in the pressure of the homogeneous vapour mixtures estimated using the above equations of state (relative deviation from the experimentally determined pressure) were comparatively low, ∼5% to 8%. However, the errors were significantly higher for the estimated pressure of vapour saturated with liquid, i.e., along the vapour–liquid phase boundary (11–15%), due to the polar nature of H 2O and H 2S and the resulting highly non-ideal behaviour of the fluid mixtures. The results of this study make it possible to reliably estimate the volumetric properties of aqueous fluids containing H 2S at temperatures and pressures up to 400 °C and 240 bar, i.e., for conditions commonly encountered in natural hydrothermal systems.

Direct prediction of the binary parameters of a cubic equation of state from those of a low-pressure gE model

This paper discusses a method for directly converting a set of binary interaction parameters of a thermodynamic model to that of another thermodynamic model without calculating phase equilibria. The proposed method assumes that the excess Gibbs energy calculated by the original model at a liquid condition is equivalent to that by the other model. To remove iterative procedures in these calculations, an empirical correlation for liquid molar volume is proposed to analytically derive activity coefficients from the equation of state. Performance of the method is examined in obtaining binary interaction parameters of an empirical mixing rule for the SRK equation of state from those of NRTL or molecular sub-group contribution parameters of UNIFAC.

Modeling of the Mixed Solvent Electrolyte System CO2−Na2CO3−NaHCO3−Monoethylene Glycol−Water

The extended UNIQUAC electrolyte activity coefficient model has been correlated to 751 experimental solid−liquid equilibrium (SLE), vapor−liquid equilibrium (VLE), and excess enthalpy data for the mixed solvent CO2−NaHCO3−Na2CO3−monoethylene glycol(MEG)−H2O electrolyte system. The model was validated by predicting the excess heat capacity. The model is consistent, and one set of binary interaction parameters are used for calculating all the properties between −50 and 90 °C. The model is compared to experimental data of infinite dilution activity coefficient measurements of MEG and may be used for calculating activities, solubility, salt hydrate properties, pH, and CO2 solubility in the NaHCO3−Na2CO3−MEG−H2O system. A simple density model of NaHCO3−Na2CO3−NaCl−MEG−water is given.

CALCULATION OF VAPOR LIQUID EQUILIBRIUM AND EXCESS ENTHALPY WITH THE UNIQUAC EQUATION

The UNIQUAC equation was used for calculation of vapor liquid equilibrium (VLE)as well as excess enthalpy (hE). Four sets of binary interaction parameters were applied: first, parameters estimated only from VLE data, then parameters from hE data for both the original UNIQUAC equation and the Anderson modification, and finally parameters estimated from hE and VLE data simultaneously. Calculations were performed for seven binary systems with polar components, representing different hE behavior. The cross-prediction of hE from VLE data works better than the reversed prediction. The model with parameters estimated simultaneously to both kinds of data can be applied successfully to both kinds of calculations, but it is a compromise between the models estimated from one kind of data.

Extended UNIQUAC model for correlation and prediction of vapour–liquid–solid equilibria in aqueous salt systems containing non-electrolytes. Part A. Methanol–water–salt systems

The Extended UNIQUAC model has previously been used to describe the excess Gibbs energy for aqueous electrolyte mixtures. It is an electrolyte model formed by combining the original UNIQUAC model, the Debye–Hückel law and the Soave–Redlich–Kwong equation of state. In this work the model is extended to aqueous salt systems containing non-electrolytes in order to demonstrate its ability in representing solid–liquid–vapour (SLV) equilibrium and thermal property data for these strongly non-ideal systems. The model requires only pure component and binary temperature-dependent interaction parameters. The calculations are based on an extensive database consisting of salt solubility data in pure and mixed solvents, VLE data for solvent mixtures and mixed solvent–electrolyte systems and thermal properties for mixed solvent solutions. Application of the model to the methanol–water system in the presence of several ions (Na +, K +, NH 4 +, Cl −, NO 3 −, SO 4 2−, CO 3 2− and HCO 3 −) shows that the Extended UNIQUAC model is able to give an accurate description of VLE and SLE in ternary and quaternary mixtures, using the same set of binary interaction parameters. The capability of the model to predict accurately the phase behaviour of methanol–water–three salts systems is illustrated.

Partitioning of some combination di‐ and tripeptides in aqueous two‐phase systems of poly(ethylene glycol) and Di‐potassium hydrogen phosphate at 293 K: Experimental results and predictions

AbstractAqueous two‐phase systems are effective extraction systems for separating peptides and enzymes from aqueous phases. Such extraction processes are based on the finding that peptides and enzymes show different preferences for the coexisting phases. Methods to calculate and predict the liquid‐liquid phase equilibrium in those systems can only be developed when an extensive experimentally determined data base is available. The present contribution contributes to that goal by presenting experimental data for the partitioning of small amounts (micrograms solute per kilogram of solution) of low molecular‐weight combination peptides of glycine, 1‐glutamic acid, 1‐phenylalanine, and 1‐lysine in aqueous two‐phase systems of di‐potassium hydrogen phosphate and poly(ethylene glycol) of molecular mass of about 6000 and 35000 at about 293 K. A group‐contribution model for the excess Gibbs energy is used to predict liquid‐liquid phase equilibrium. A preliminary set of binary interaction parameters was taken from the literature. These model parameters were determined using experimental results for the partitioning of single amino acids and some of their peptides in the same aqueous two‐phase system. No experimental results for the partitioning of combination peptides had been used for parameter estimation, i.e. those peptides were products of condensation reactions of molecules of a single amino acid. Therefore, partition coefficients calculated for combination peptides are predictions. For some peptides predicted and measured partition coefficients agree within experimental uncertainty. In a few cases predicted partition coefficients deviate from experimental results by a factor of about two. However, the model always correctly predicts which phase (polymer‐rich or salt‐rich) is preferred by the peptide.

Improved modelling of vapour-liquid equilibria up to the critical region. Application to the CO 2CH 4N 2 system

A new procedure for extending the applicability of cubic EOS to critical conditions is described. This method requires to determine two sets of optimum binary interaction parameters for the non-critical and critical parts of PTx experimental data of binary systems. The effective binary interaction parameters are calculated by interpolation between these two sets of binary interaction parameters. The interpolation factor is a function of a distance from critical conditions, which is evaluated from an a priori calculation of the molar volumes of coexistent liquid and vapour. The algorithm is shown to improve the prediction of the Soave-Redlich-Kwong equation of state in the ternary CO 2CH 4N 2 system. Application conditions of this approach to other systems are discussed.

Peng-Robinson predictions for hydrocarbons, CO2, N2, and H2 S with pure water and NaCI brine

Søreide, I. and Whitson, C.H., 1992. Peng-Robinson predictions for hydrocarbons, CO2, N2 and H2S with pure water and NaCI brine. id Phase Equilibria 77: 217-240. Attempts at predicting mutual solubilities with a conventional cubic equation of state (EOS) including the effect of salts in the aqueous phase have so far been limited. The main purpose of this work is to provide a simple and novel approach for predicting mutual solubilities of brine/hydrocarbon mixtures with an EOS at high pressures and temperatures, including the effect of salinity in the aqueous phase. The Peng-Robinson EOS 2 has been applied in this study with two modifications: (1) an α-term in the EOS constant a has been developed specifically for the water/brine component as a function of sodium chloride (NaCl) brine salinity and pure water reduced temperature, TI, and (2) two sets of binary interaction parameters (BIP) in the classical mixing rule for mixture EOS constant a have been determined as a function of acentric factor, temperature, and salinity. Experimental data of vapor pressures and mutual solubilities provide the basis for the proposed methods. Applications of the methods described include phase behavior prediction of reservoir gas-oil/brine systems at high pressures, including (1) gas solubility in water/brine and (2) water solubility in hydrocarbon reservoir fluids.

Correlation of solid—liquid and vapor—liquid equilibrium data for polynuclear aromatic compounds

Solid—liquid equilibrium (SLE) data were measured for five solutes in cis-decalin from ambient temperature to the melting point of the solutes. These SLE data plus our previous data for the same solutes in tetralin were used to determine experimental activity coefficients and interaction parameters using the UNIQUAC model. This set of interaction parameters gave a good representation of the experimental SLE data but were not satisfactory generally for predicting vapor—liquid equilibria for these systems. However, in an alternative approach, the solid solubility data and one vapor—liquid equilibrium point for each isotherm from previous work were used to determine another set of binary interaction parameters in the UNIQUAC model using a gradient-based search technique. The calculated values of parameters were used then to predict the vapor—liquid equilibrium for that system. It was found that the solid solubility and one vapor—liquid equilibrium data point were sufficient to predict the vapor—liquid equilibrium curve for the binary systems studied. Finally, all the solid solubility and vapor—liquid equilibrium data were combined to determine global parameters for the ten binary systems using the UNIQUAC model.