Component Mole Research Articles

Viscosities of diethylene glycol (DEG) + 2-amino-2-methyl-1-propanol (AMP) + water

In this study, the viscosities (η) of the aqueous mixed-solvent system of diethylene glycol (DEG) and 2-amino-2-methyl-1-propanol (AMP) were investigated at normal atmospheric pressure over the range of temperature of 303.15 - 343.15 K and across varying component mole fractions range [0.02 to 0.60 for DEG (x1 ), 0.02 to 0.60 for AMP (x2 ), and 0.20 to 0.80 for H2O (x3 )]. The calculated properties were fitted to a modified equation originally proposed by Grunberg and Nissan for the viscosity of liquid mixtures to correlate temperature and composition dependency of the measured property. In comparison to literature values, the uncertainty of the kinematic viscosities was approximated to be + 1.0 %, and that the correlations used satisfactorily represent the effects of temperature and composition on the viscosities of the considered mixed-solvent system as shown by the low overall average absolute deviations obtained in the calculations. The properties obtained and reported in this work are, in general, of adequate correctness for most engineering-design calculations, such as the design of absorption process for carbon dioxide capture using mixed-solvents as absorbents.

Improved Minimum Miscibility Pressure Prediction for Gas Injection Process in Petroleum Reservoir

Determination of gas–oil minimum miscibility conditions is one of the important design parameters to improve the displacement efficiency of the hydrocarbon reservoir during enhanced oil recovery with gas injection. In this work, a support vector regression (SVR) model is developed using experimental data to estimate the minimum miscibility pressure (MMP) for various reservoir fluids and injection gases. Experimental MMP data taken from the reliable literature were used as input. Each data point input includes methane and intermediate components mole percent, plus fraction properties and reservoir temperature related to reservoir fluid and CO2, H2S, N2 and intermediate mole fractions, and intermediate properties of the injected gas. Experimental MMP is regarded as the model output. The database contains 135 datasets, from which 125 datasets were used for model development, and the rest were used for model evaluation. Genetic algorithm was implemented to optimize the SVR model parameters. The proposed data-driven model was verified by statistical validation data. The model results illustrate a correlation coefficient (R2) of 0.999. In addition, the SVR results demonstrate the proposed model to be a fast tool and a robust approach to map input space to output features. The SVR model was compared to popular data-driven MMP estimation models as well. This comparison presents an acceptable accuracy relative to this estimation model. Finally, the presented model was evaluated against a comprehensive theoretical model of slim tube compositional simulation on a trusted literature dataset.

Mixing enthalpy of Ag–Sn system at 1150 °C

This paper presents thermodynamic results of Ag–Sn alloys mixing at 1150 °C. The need for binary data on mixing enthalpy ΔH mix appeared obvious in the process of calorimetric study of the ternary system Ag–Cu–Sn known as the promising lead-free solder. The mixing enthalpies of Ag–Sn system were measured by drop calorimetry method using SETARAM MHTC thermal analyzer. All the tests were conducted in the dynamic protective atmosphere of argon. The calorimeter’s sensitivity calibration was performed with the use of pure metals (Ag, Sn) and standard leucosapphire samples and consisted of two stages. The use of two-stage calibration procedure improves significantly the convergence of two branches of ΔH mix isotherm plotted from the pure component toward each other. The experimental results were approximated with analytical function using quasi-chemical modification of subregular solutions model (quasi-chemical model of Sharkey et al.) postulating the presence of both pair and triple interactions in solution. The resultant equation is ΔH mix = N Ag·N Sn·(− 27.7075·N Ag − 0.9977·N Sn + 27.7079·N Ag·N Sn), kJ mol−1, where N is the component mole fraction. The measured compositional dependence of ΔH mix is substantially asymmetric like the previous results of the other authors, but, in contrast to those results, it does not change the sign and is entirely negative in the whole range of concentrations.

Internally heat integrated batch distillation: Vapor recompression and nonlinear control

Abstract This work proposes a vapor-recompressed heat integration scheme in batch distillation column and its nonlinear control. For this, first a thermal coupling is made to form a heat integrated batch distillation column (HIBDC). To further improve energetic and economic potential, a mechanical heat pump system is introduced in the HIBDC, which gives rise to the vapor-recompressed HIBDC (VRHIBDC). For a ternary hydrocarbon system, this VRHIBDC exhibits superiority in the aspects of energy savings and economic performance over the HIBDC with respect to the conventional batch distillation column (CBDC). Aiming to achieve a constant product composition and to collect higher amount of distillate from the VRHIBDC column, an extended generic model controller (EGMC) is formulated. To obtain the state information required for this model-based controller simulation, two nonlinear observers, namely high gain observer (HGO) and extended Kalman filter (EKF), are devised and then coupled with the EGMC, yielding the EGMC-HGO and EGMC-EKF, respectively. To avoid the design complexity and computational load, both the observers are designed based on only the component mole balance equation around the reflux drum. The open-loop performance of the EKF shows its superiority over the HGO for the same example system. Subsequently, the comparative closed-loop performance is evaluated between the EGMC-HGO and EGMC-EKF with respect to a traditional proportional-integral (PI) controller. It is investigated that the EGMC-EKF shows the best result followed by EGMC-HGO.

Slip at liquid-liquid interfaces

A new study shows that the need for slip models at interfaces and detailed molecular dynamics simulations can be obviated by continuum models that only require knowledge of the density, component mole fractions, and the dependence of the viscosity on the density

Evaluating Transport Properties of LiPF6 in Concentrated EC/DEC Electrolytes By Self-Diffusivity from NMR

Accurate prediction of the lithium ion battery charge-discharge behavior is critically important in many battery applications1, including for the high-power, high-energy battery packs used in electric vehicles. Accurate model predictions by, for instance, the classical porous electrode model developed by John Newman2, require accurate electrolyte solution transport properties. In this work, the self-diffusivities of all species in LiPF6/EC/DEC electrolyte solutions were characterized by PFG-NMR, and the protocol reported by Kim and Srinivasan3was used to evaluate the transport properties. Experimental All chemicals were purchased from BASF. LiPF6 in EC/DEC (w/w 50:50) of different concentrations (1.5M to 0.1M) were prepared inside an argon-filled glove box and sealed in aluminum bottles before the PFG-NMR measurement.5 Diffusion coefficients (D) of the Li+, PF6 - , and EC/DEC were measured by 7Li 19F and 1H PFG stimulated echo NMR spectroscopy. Since resonances from EC, DEC are separated in one-dimensional 1H spectra, separate diffusion coefficients could be measured. Experiments were performed at Larmor frequencies of 599.82 and 564.3 MHz for 1H and 19F, respectively, over the temperature range of 0 to 40 oC using a 14.1 T (600 MHz 1H) NMR spectrometer (Agilent) equipped with a 5 mm z-gradient probe (Doty Scientific), which can generate a maximum gradient strength of approximately 31 T/m. The echo heights, S(g), recorded as a function of gradient strength, g, were fitted with the Stejskal-Tanner equation (equation 1), RESULTS AND DISCUSSIONShown in Figure 1 is the concentration dependence of self-diffusivity of LIPF6/EC/DEC measured by PFG-NMR for Li+, PF6 -, EC and DEC. Careful inspection of the data leads to several conclusions below: I. the self-diffusivities of all species decrease as the concentration increases or the temperature decreases, which is expected from the Stokes-Einstein equation II. the self-diffusivity values are ordered as follows EC≈DEC>PF6 ->Li+ III. the concentration dependence of self-diffusivity for PF6 -is stronger than other species, especially at lower concentrations, e.g. 0.1 M to 1.0 M, while Li+ shows the weakest dependence. The generalized-Darken relation (Equation 1) for translating self-diffusivities and of species i and j into binary diffusivities, Dij, is given by equation (2): where xi , xj , are component mole fractions. This relation was validated by Krishna and van Baten4. The resulting Fickian diffusivity values decrease as the concentration increases in a narrow range (3.7x10-10 to 2.4x10-10m2/s), and have similar magnitudes to these reported in EC/DEC or PC/EC/DMC as measured by electrochemical methods over a wide range of concentrations. Lundgren et al. 6 reported that the Fickian diffusivities of LiPF6 in the same electrolyte decreased from 2.8x10-10m2/s to 2.0x10-10 m2/s in the range of 0.5M to 1.5M, as measured by galvanostatic polarization experiments (red connected points, Figure 2); Valøen and Reimers 7 measured the Fickian diffusion coefficients of LiPF6in a PC/EC/DMC mixture (10:27:63) (blue connected points, Figure 2). Reference 1. L. Cai, R. E. White J. Power Sources14 (2011): 5985. 2. J. Newman, W. Tiedemann, Aiche Journal21 (1975), 25. 3. S. Kim, V. Srinivasan, J. Electrochem. Soc. 163(2016), A2977. 4. R. Krishna, J. M. van Baten, Ind. Eng. Chem. Res., 44(2005), 6939. 5. K. Han, N. Rajput, X. Wei, W. Wang, J. Hu, K. Persson, K. Mueller J. Chem. Phys., 141(2014), 104509. 6. H. Lundgren, M. Behm, G. Lindbergh, J. Electrochem. Soc., 162(2015), A413. 7. Lars Ole Valøena, and J. Reimersa, J. Electrochem. Soc., 152 (2005), A882. Figure 1

General solutions to decompose heterogeneous compositions using antibody afucosylation as a model system.

Methods involving the use of mathematical models of competitive ligand-receptor binding to characterize mixtures of ligands in terms of compositions and properties of the component ligands have been developed. The associated mathematical equations explicitly relate component ligand physical-chemical properties and mole fractions to measurable properties of the mixture including steady state binding activity, 1/Kd,apparent or equivalently 1/EC50, and kinetic rate constants kon,apparent and koff,apparent allowing: (1) component ligand physical property determination and (2) mixture property predictions. Additionally, mathematical equations accounting for combinatorial considerations associated with ligand assembly are used to compute ligand mole fractions. The utility of the methods developed is demonstrated using published experimental ligand-receptor binding data obtained from mixtures of afucosylated antibodies that bind FcγRIIIa (CD16a) to: (1) extract component ligand physical property information that has hitherto evaded researchers, (2) predict experimental observations, and (3) provide explanations for unresolved experimental observations. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:500-510, 2017.

Parameters Affecting the Efficiency of a Heat Transformer with a Particular Focus on the Heat Solution

Abstract The heat transformer is a reverse cycle absorption machine, suitable for the direct exploitation of heat wastes and solar energy. Part of these wastes are “transformed” into thermal energy at a higher temperature than the one provided. Hence some studies concern the evaluation of the performances of the working fluids used. They must ensure a high level of efficiency which, as for the conventional absorption machines, depends on several parameters. One of these parameters is the heat solution: it is defined as the heat absorbed when a mole of a given component is mixed with the amount of the other component required to generate the desired solution at a certain temperature and pressure. This is the reason why the decision was to examine its influence with respect to machines exerting two different fluids which are generally used. The first one is NH 3 -H 2 O, whereas the second is H 2 O-LiBr; they used as refrigerating substances ammonia and water respectively and as absorption substances water and lithium bromide. Through an analytical modeling and the processing of experimental data provided by the bibliography, it was possible to show how, for these fluids, the terms of the sensible heat represent a moderate fraction of the global energy balance, at one condition though: highly efficient recovery exchangers must be present. Moreover there were reported values of the refrigeration effect of the order of thousands of kJ/kg with satisfying responses energetically speaking. Then a high stability of the fluid NH 3 -H 2 O was revealed, as testified by the high value of the difference between the concentration of the refrigerator in the absorber and the concentration of the refrigerator in the generator.

Linking fluid composition to black-oil properties

Field development studies require, among many other things, reliable estimates of fluid properties. In cases where experimental data is unavailable or incomplete, it is necessary to predict fluid properties using correlations, based on input variables such as temperature, API, saturation pressure, gas gravity, and flash GOR. However, there are situations when even these input variables are not known, and where the only information is the initial reservoir fluid composition.The scope of the present work is to develop a predictive method which links the reservoir fluid composition to the input variables needed for the black-oil property correlations. The method is based on analysis of several experimental data sets comprising in total several hundred fluid compositions with associated black-oil properties as well as on isothermal flash calculations on 500,000 synthetic, but realistic, fluid compositions spanning a large range in compositional space. The aim of this work is therefore not to develop new correlations for oil compressibility, formation volume factors, viscosities etc. Rather, the contribution should be regarded as a novel way to incorporate reservoir fluid compositional information into an already existing framework for predicting fluid properties used for field development studies.Results from the study show that it is possible to predict API, flash gas gravity, flash GOR and saturation pressure with reasonable accuracy for a large range of reservoir fluid compositions as long as the molecular weight of the plus fraction is known. The work sheds more light on the quantitative influence of individual component mole fractions on fluid properties.

On a choice of independent variables in Newton iterations for multiphase flash calculations

Multiphase split calculations consist in the minimization of the Gibbs free energy. If the second-order Newton method is used, either component mole numbers or the logarithms of equilibrium constants (lnK) are selected as independent variables. Several recent papers advocated the use of the phase mole fractions together with lnK as independent variables in Newton iterations (lnK-θ). Unlike in the lnK approach, there is no explicit resolution of the Rachford-Rice (RR) equations, which are solved implicitly during the Newton update. The resulting linear system is non-symmetric and is solved by Gaussian elimination. In this study, this latter choice of variables is analyzed in detail, and an efficient formulation is proposed in which algebraic transformations are used to recast the lnK-θ method in a way that enables using the symmetry efficiently, both for constructing the Jacobian matrix and for solving the linear system of equations using a Cholesky factorization. Taking advantage of the block structure of the Jacobian matrix, it is revealed that the matrix of the linear system is formally identical to the Jacobian of lnK (evaluated at a lower implicitness level) and phase mole fraction can be updated separately using the partial solution of this system. Numerical experiments carried out on several multiphase mixtures exhibiting complex phase envelopes show the robustness and the efficiency of the proposed approach as compared to the original lnK-θ methodology, with the observed computational time savings up to 25%.

Erosion corrosion failure analysis of the elbow in sour water stripper overhead condensing reflux system

The erosion corrosion failure of elbow of one oil refinery was investigated by using Aspen software, CFD technology and experiments. And the gas–liquid equilibrium distribution of H2S and NH3 and multiphase flow simulation in the overhead system of a sour water stripper were obtained. The result shows that the component mole fraction of H2S and NH3 rises markedly with decreasing temperature. At the outlet of air cooler, the temperature drops to 85°C to form high concentration of ammonium bisulfide (NH4HS), which would cause serious erosion corrosion at a certain flow rate and reveals an inhomogeneous thinning. The liquid phase fraction mainly distributes on the outside part of elbow, the more sour water accumulates there resulting in localized corrosion thinning. Meanwhile, the experiments show that when the concentration of NH4HS reaches 10wt.%, the corrosion rates increase rapidly with increased velocity. Thus controlling the concentration of NH4HS below 10wt.% in reflux drum would reduce the risk of erosion corrosion failure.

CMFD simulation of ERCOSAM PANDA spray tests PE1 and PE2

The ERCOSAM project (together with the SAMARA project) includes a set of multi-stage experiments carried out at different thermal-hydraulics facilities (TOSQAN, MISTRA, PANDA, SPOT) and their numerical simulation. The test sequences aim to investigate hydrogen concentration build-up and stratification during a postulated severe accident as well as the effect of activation of Severe Accident Management systems (SAMs) on stratification. At the initial Phases I–III of the tests stratification of the injected light gases (steam, helium) is established, pressure increases. The models of SAMs are activated at the final Phase IV.In the paper, two spray tests PE1 and PE2 performed at PANDA facility are numerically investigated aiming for code validation (FLUENT) and better understanding of physical processes. Phases I–IV of the tests were simulated. A satisfactory agreement with the experimental results on gas component mole fractions was obtained. The reasons of obtained some discrepancies in pressure and temperature were studied in multivariate calculations and discussed in the paper. The tests PE1 and PE2 were performed with different spray nozzles and initial conditions. In simulation that resulted in different flow patterns during spray operation. The sensitivity to nozzle angle and some other input parameters was investigated. Possible factors of depressurization rate caused by spray operation were also studied. The key features observed in the experiments and obtained numerically being of interest in terms of CFD applications to NPP hydrogen safety are summarized.

Gas Injection for Enhancement of Condensate Recovery in a Gas Condensate Reservoir

Gas condensate reservoirs suffer losses in well productivity due to near wellbore condensate dropout when the flowing bottom-hole pressure declines below the dew point pressure. Pressure maintenance and gas cycling are the common practices used in the oil and gas field to alleviate this problem and develop gas condensate reservoirs. The injection of dry gas into a retrograde gas condensate reservoir helps in vaporizing the condensate and increases its dew point. This article investigates the situation of one of the reservoirs located in southern Iran in Zagros area. First, based on the reservoir composition, the phase diagram has been plotted. Peng–Robinson equation of state for the equilibrium calculations and Lee–Kesler characterization of heavy fractions are used in this software. After that the effect of nitrogen, pure methane, a composition of ethane and methane, and carbon dioxide injections on reservoir recovery has been investigated and compared to a natural depletion scheme. The full system, including two separators and a stock tank, are simulated simultaneously and the effect of each type of injection on the liquid and gas production is investigated. Full mixing has been assumed in all of the injections studied. By comparing between the results it is concluded that in an injection process, required injection rate to maintain reservoir pressure above dew point pressure and avoid liquid formation in the reservoir for pure methane, a composition of ethane and methane, pure nitrogen and carbon dioxide, and liquid recovery in all cases are investigated. According to the results, with increasing ethane mole percent in the injecting gas a lower injecting rate for the same liquid recovery is needed. Because with increasing heavy components mole percent in injecting gas, average molecular weight of injecting gas, and reservoir gas becomes closer and there will be a better mixing between them and, therefore, liquid recovery will be improved. Thus, a composition of ethane and methane with more ethane mole percent is better than others.

Helmholtz function-based global phase stability test and its link to the isothermal–isochoric flash problem

The global phase stability test is formulated based on the Helmholtz function. The corresponding phase stability function is minimized and, if the system is found to be unstable, the initial estimates for the properties of the incipient phase are such that the system's Helmholtz function after its incipient partition is smaller than before the partition. This ensures trivial solutions are avoided in flash problems with specifications of temperature, volume, and component mole numbers. Also, there is no need for reformulation of the thermodynamic model as in procedures proposed earlier for similar purposes. The procedure succeeded in the stability analysis of several situations previously used as test cases in the literature.

Reduced-Order Modeling for Compositional Simulation by Use of Trajectory Piecewise Linearization

Summary Compositional simulation can be very demanding computationally as a result of the potentially large number of system unknowns and the intrinsic nonlinearity of typical problems. In this work, we develop a reduced-order modeling procedure for compositional simulation. The technique combines trajectory piecewise linearization (TPWL) and proper orthogonal decomposition (POD) to provide a highly efficient surrogate model. The compositional POD-TPWL method expresses new solutions in terms of linearizations around states generated (and saved) during previously simulated “training” runs. High-dimensional states are projected (optimally) into a low-dimensional subspace by use of POD. The compositional POD-TPWL model is based on a molar formulation that uses pressure and overall component mole fractions as the primary unknowns. Several new POD-TPWL treatments, including the use of a Petrov-Galerkin projection to reduce the number of equations (rather than the Galerkin projection, which was applied previously), and a new procedure for determining which saved state to use for linearization are incorporated into the method. Results are presented for heterogeneous 3D reservoir models containing oil and gas phases with up to six hydrocarbon components. Reasonably close agreement between full-order reference solutions and compositional POD-TPWL simulations is demonstrated for the cases considered. Construction of the POD-TPWL model requires preprocessing overhead computations equivalent to approximately three or four full-order runs. Runtime speedups by use of POD-TPWL are, however, very significant—up to a factor of 800 for the cases considered. The POD-TPWL model is thus well suited for use in computational optimization, in which many simulations must be performed, and we present an example demonstrating its application for such a problem.

Ternary diffusion coefficients of nickel chloride plus theophylline plus water at 298.15 K

Ternary mutual diffusion coefficients (D11, D22, D12 and D21) for aqueous solutions containing nickel chloride and theophylline (THP), at T=298.15K, and at different carrier concentrations were measured by using the Taylor technique. The results are compared with those obtained for the binary systems H2O–NiCl2 and H2O–theophylline, already published. These data permit us to have a better understanding of the structure of this ternary system and its thermodynamic behaviour. For example, it is possible to take conclusions about the influence of this electrolyte in diffusion of THP, and to estimate some parameters, such as the number of moles of each component transported per mole of the other component driven by its own concentration gradient.

Using a Committee Machine With Artificial Neural Networks To Predict PVT Properties of Iran Crude Oil

Summary Reservoir-fluid properties are very important in material-balance calculations, well testing, and reserves estimates. Ideally, those data should be obtained experimentally. Sometimes, the results obtained from experimental tests are not reliable or accessible. In this study, we predict the pressure/volume/temperature (PVT) properties by a new artificial-neural-network (ANN) model using component mole percent, solution gas/oil ratio (GOR) (Rs), bubblepoint pressure (Pb), reservoir pressure, API oil gravity, and temperature as input data. The employed ANN model is from the committee machine type. The designed model processes its inputs using two parallel multilayer perceptron (MLP) networks, and then recombines their results. The results obtained show that the committee-machine model is a dependable network for prediction of PVT properties in reservoirs among the other ANNs and empirical correlations.

Chemistry and Origin of Enigmatic Monazite and Chevkinite/Perrierite in the Egyptian Black Beach Sand

AbstractThe content of monazite in the Egyptian black beach sand and coastal sand dunes is normally equal to or below 0.01 wt.%. The obtained high grade monazite concentrate includes three minor monazite groups in addition to major canary and lemon yellow coloured monazite: (i) the colourless to pinkish white coloured monazite; (ii) the opaque light to dark resinous, reddish brown and dark brown coloured monazite; and (iii) opaque yellowish red to brownish red coloured monazite grains group. These groups represent 3%, 4% and 2%, respectively, in the high grade monazite concentrate. A negligible amount of euhedral to subhedral black to brownish black chevkinite/perrierite mineral crystals was detected in the obtained monazite concentrate. The presence of these minor mineral groups affects the chemical composition of the obtained high grade monazite concentrate.The Ce2O3 is the main REE in the studied monazite. In the colourless‐pinkish monazite grains, the analyzed REE are the following, in order of abundance; Ce > La > Nd > Pr > Sm > Gd > Dy. UO2 ranges between 0.11 and 1.74 wt.%. The contents of Eu2O3 is under the limit of detection while ThO2 ranges between 3.99 and 8.58 wt.% with an average value of 5.57 wt.%. These grains are most probably igneous monazite from a highly differentiated granite.The resinous, brown monazite grains have lower Ce2O3 content (24.63 wt.%) and much lower La2O3 content (6.00 wt.%) but greater content of Eu2O3 (0.41 wt.%) than those of the colourless‐pinkish monazite. These monazites have the lowest contents of Th, U and Ca among the three groups. The resinous, brown monazites are most probably formed by metamorphism or alteration leading to leaching or replacement of pre‐existing minerals.The red monazite group has a lower average Ce2O3 content (25.28 wt.%) than the colourless‐pinkish variety (28.02 wt.%) but slightly greater than that of the resinous, brown ones. The red monazite group has the highest ThO2 and UO2 contents; 5.84 wt.% and 1.24 wt.%, respectively. It has the lowest monazite component mole fraction (0.75). The red monazite seems to have been formed by hydrothermal alteration of pre‐existing monazite and other mineral species bearing for Y, REE, Ca, Th and U.The two coupled substitution mechanisms: (Th, U)4++ Ca2+ 2REE3+, and (Th, U)4++ Si4+ REE3++ P5+, are obvious in the studied colourless‐pink monazite.

Interaction between calcium chloride and some carbohydrates as seen by mutual diffusion at 25 °C and 37 °C

Ternary mutual diffusion coefficients measured by Taylor dispersion method ( D 11, D 22, D 12 and D 21) are reported for aqueous solutions of calcium chloride (CaCl 2) and some carbohydrates (glucose, fructose and sucrose) at 25 °C and 37 °C at carrier concentrations from 0.000 to 0.100 M, for each solute, respectively. These diffusion coefficients have been measured to gain a better understanding of the structure of these systems and thermodynamic behaviour of CaCl 2 and carbohydrates in solution. For example, from these data it will be possible to estimate some parameters, such as the number of moles of each component transported per mole of the other component driven by its own concentration gradient. Significant effects on these data were observed in the presence of these carbohydrates (especially with sucrose), suggesting interactions between them and calcium chloride. These studies have been complemented by molecular mechanics calculations.

Composition of heteroassociates formed in an HF-diethyl ketone liquid binary system

The IR spectra and solution densities in a binary liquid system (BLS) HF-diethyl ketone were measured for the first time upon variation of the component molar ratio from 1: 12 to 12: 1 and to 27: 1, respectively. Analysis of the concentration dependences of normalized (to the total number of moles of BLS components in 1 L) optical density and excess density of the solutions revealed the presence of 1: 1, 4: 1, and ∼12: 1 heteroassociates (HAs). For each associate, the concentration range in which it forms in the HF-(C2H5)2CO binary mixture was estimated. It was shown that, at component molar ratios from 2: 1 to 9: 1, all three types of HAs are present simultaneously.