Composition Of Binary Mixtures Research Articles

Vapor–liquid phase equilibrium prediction for mixtures of binary systems using graph neural networks

AbstractVapor–liquid phase equilibrium (VLE) plays a crucial role in chemical process design, process equipment control, and experimental process simulation. However, experimental acquisition of VLE data is a challenging and complex task. As an alternative to experimentation, VLE data prediction offers great convenience and utility. In this article, an artificial intelligence network is proposed to predict the temperature and the vapor phase composition of binary mixtures. We constructed a graph neural network (GNN) and designed an uncertainty‐aware learning and inference mechanism (UALF) in the prediction process. The model was tested on both a self‐constructed dataset and a publicly available dataset. The results demonstrate that the proposed method effectively reveals the phase equilibrium properties of the target data. This work presents a novel approach for predicting vapor–liquid phase equilibrium in binary systems and proposes innovative ideas for investigating phase equilibrium mechanisms and principles.

Experimental Determination of the Temperature‐Dependent Broadening Effect of Water Vapour on the S‐Branch Raman Linewidths of Nitrogen

ABSTRACTThis work reports the S‐branch Raman linewidths of N2 broadened by H2O vapour at temperatures 870–1900 K determined using the picosecond time‐resolved pure rotational coherent anti‐Stokes Raman scattering (RCARS) approach. The coherent dephasing time constant of nitrogen in a binary mixture was determined from the time trace fitting of the RCARS signal. Raman linewidths of N2 for four different binary mixture compositions up to 20% H2O were obtained for each temperature and the N2‐H2O broadening coefficient was determined. The decay of nitrogen broadened by water vapour is faster than that of self‐broadened nitrogen for all temperatures leading to a higher Raman linewidth. Respectively, the S‐branch Raman linewidths of N2‐H2O deviate significantly in magnitude and slope from the Q‐branch Raman linewidth calculated by the modified energy gap (MEG) law. Therefore, taking into account the broadening effect of water molecules in nitrogen has the potential to significantly improve thermometry and species concentration determination. The determined S‐branch Raman linewidths and broadening coefficient will therefore find application in combustion and reactive flow diagnostics.

Drag reduction and degradation of binary polymer solutions

Polymer-induced drag reduction has yielded great potential benefits for industrial processes after more than 70 years of research. However, the limitation of low shear stability has hindered further applications. This study investigates the rheology, drag reduction rate (DR), and degradation of binary polymer mixtures comprising a rigid polymer (diutan gum, DG) and a flexible polymer (polyethylene oxide, PEO). The solutions all exhibited shear-thinning behavior, and the mixed solution was less viscous than the pure PEO or DG solutions at the total concentration of 100 ppm. When fixing the PEO concentration at 50 ppm, the mixed solution viscosity significantly increased with the DG concentration. The drag reduction performance of the pure PEO solution, pure DG solution, and various proportions of binary polymer mixtures was analyzed using an in-house rotor device. The DRs of the solutions increased with the Reynolds number (Re), and decreased with shearing time. The binary solution significantly improved the shear stability of the solution without loss of DR compared to the pure PEO solution. The theoretical model for molecular degradation in turbulent flow excellently fitted the experimental data of relative drag reduction with time. Furthermore, the synergistic interaction parameter was calculated, and it was positive for most cases in the mixtures. Additionally, when Re was fixed, the synergistic interaction parameter, related to the composition of binary polymer mixtures, initially decreased and then increased with time.

Prediction of azeotropes position of refrigerant mixtures using the PHSC EoS

The work aims is predict the azeotropes' position in refrigerant mixtures using the Perturbed Hard Sphere Chain (PHSC) equation of state (EoS). The vapor-liquid equilibrium (VLE) of seventeen binary refrigerant mixtures has been correlated using two model-adjustable parameters. The results show that the proposed model can calculate the bubble and dew points of binary systems, accurately. The average ARD value of binary VLE calculations has been obtained 1.28 %. The azeotropes pressure and composition of binary mixtures have been predicted using the PHSC EoS with the average ARD values of 1.043 % and 2.23 %, respectively. The maximum relative deviation has been observed for R717+R125 systems with two azeotropes points; ARDx=12.2 %. The performance of the PHSC EoS has been evaluated by predicting the azeotropes position of ternary mixtures. The PHSC EoS results have been compared to three cubic-based EoSs containing the PR-vdW, PR-BM, and PR-MHV2-NRTL models. The results show that the PHSC EoS can predict the ternary VLE data and azeotropes position satisfactory. The relative absolute deviation does not exceed 1.7 % for the azeotropes pressure. The PHSC EoS can be used as a robust and efficient model for the prediction of the azeotropes' position in binary and ternary refrigerant mixtures. Prediction of azeotropic composition helps us to find promising refrigerant candidates in the pre-design stage of the desired apparatus.

Rapid investigation of the effect of binary and ternary solvent gradient mixtures on reaction outcomes using a continuous flow system

A flow technique for rapid investigation of the effects of solvents mixtures on organic transformations was developed. Reaction information against a full range of binary or ternary solvent mixture composition was obtained in a time efficient manner.

Influence of bed material on biomass gasification in fluidized beds via a TFM-DEM hybrid model

In the biomass gasification process, mixing and segregation behaviors of fuel particles and bed materials greatly influence the performance. In this work, the Two-Fluid Model-Discrete Element Method (TFM-DEM) hybrid model is employed to evaluate the impact of bed material on biomass gasification in a fluidized bed reactor, where fuel particles and bed material particles are described by the Lagrangian method and Eulerian method respectively. The biomass particle size distribution is taken into consideration. The kinetic theory of rough sphere (KTRS) is employed to consider the rotation impact of bed materials. Flow behaviors of binary mixture and gas composition distribution are analyzed. The results reveal that the bed materials with greater size can hinder the particle mixing behaviors and make the biomass particles concentrate on the bed surface so as to increase the non-uniformity of temperature distribution in the bed. A good fluidization with smaller bed material particles is beneficial to hydrogen production.

Investigation of ethanol-phenol interactions used in steam reforming process: Molecular level understanding through experimental and theoretical studies

Ethanol-phenol binary mixtures are used as feed for hydrogen production in the steam reforming process. The present work investigates the physicochemical properties of the various compositions of ethanol-phenol binary mixtures experimentally to understand the interactions of these two molecules at the molecular level. The densities (ρ) and sound velocities (U) values of the binary mixtures increased with the mole fraction of the phenol. The excess molar volume (VmE) and various acoustic parameters such as acoustic impedance (ZE), compressibility (βsE), and intermolecular free length (LfE) were computed in the whole mole fraction range. The negative values of VE, LfE, βsE and positive values of ZE, UE up to a 0.5 mole fraction of phenol indicate strong intermolecular interaction between dissimilar molecules than similar molecules. DFT/B3LYP computational methods were used to optimize the structure of the monomer of ethanol and phenol and the dimers, ethanol-ethanol, ethanol-phenol, and phenol-phenol with a 6-311G ++ (d, p) basis set. The variation of energy of all-possible conformers of homo and hetero molecular dimers of ethanol and phenol was computed by varying the distance between the molecules. The energy values obtained in the computational method supported the experimental findings well and envisaged the significant interaction between ethanol-phenol than ethanol-ethanol and phenol-phenol binary mixture at a 1:1 composition. Summarizing, the 1:1 stoichiometric ratio of the ethanol-phenol binary mixture could be the appropriate feedstock for optimal hydrogen production in the steam reforming process, and accordingly suitable substitute of this mixture can be designed to lessen the overload on ethanol-phenol mixture.

Methane and ethane detection from natural gas level down to trace concentrations using a compact mid-IR LITES sensor based on univariate calibration

A gas sensor based on light-induced thermo-elastic spectroscopy (LITES) capable to detect methane (C1) and ethane (C2) in a wide concentration range, from percent down to part-per-billion (ppb), is here reported. A novel approach has been implemented, exploiting a compact sensor design that accommodates both a custom 9.8 kHz quartz tuning fork (QTF) used as photodetector and the gas sample in the same housing. The resulting optical pathlength was only 2.5 cm. An interband cascade laser (ICL) with emission wavelength of 3.345 µm was used to target absorption features of C1 and C2. The effects of high concentration analytes on sensor response were firstly investigated. C1 concentration varied from 1% to 10%, while C2 concentration varied from 0.1% to 1%. These ranges were selected to retrace the typical natural gas composition in a 1:10 nitrogen dilution. The LITES sensor was calibrated for both the gas species independently and returned nonlinear but monotonic responses for the two analytes. These univariate calibrations were used to retrieve the composition of C1-C2 binary mixtures with accuracy higher than 98%, without the need for further data analysis. Minimum detection limits of ∼650 ppb and ∼90 ppb were achieved at 10 s of integration time for C1 and C2, respectively, demonstrating the capability of the developed LITES sensor to operate with concentration ranges spanning over 6 orders of magnitude.

Effect of CO2-based binary mixtures on the performance of radial-inflow turbines for the supercritical CO2 cycles

Recently, the supercritical carbon dioxide (SCO2) power cycle has become a hotspot in the field of energy-efficient utilization. The utilization of additives in the power cycle has been proven to be an effective way to improve the SCO2 power cycle efficiency. As one of the core components of the system, the influence of CO2-based mixtures on turbine performance needs to be further explored. In this study, the preliminary design and three-dimensional numerical simulation of a 500kW radial-inflow turbine (RIT) for small-scale SCO2 power systems were carried out. Furthermore, the design and off-design performance of high Reynolds number and small size turbine under the change of the CO2-based binary mixture compositions and mixing ratios were studied. Increasing the amount of nitrogen, oxygen, or helium into CO2 has a negative effect on the RIT performance, and the appropriate amount of xenon or krypton can improve the turbine efficiency. Moreover, mixtures with higher krypton additions adapt to higher heat source conditions. The loss of the turbine stage passage shows that a large amount of helium greatly reduces the working fluid density, and the high amount of xenon has a great influence on the dynamic viscosity, which all makes the RIT operation deviate from the steady state. Therefore, the CFD model simulation fails indicating that RIT designed based on pure CO2 may not run smoothly and continuously. The losses in the stage with pure CO2 and CO2–Kr mixture were investigated. The results indicate that the losses originated from the stator cannot be ignored and that the improvement of efficiency is mainly owed to the reduction in clearance losses. There is no doubt that the viewpoints proposed in this paper have significant reference value for the practical application of the SCO2 power cycle using mixtures.

Combined experimental and molecular dynamic simulation study on low pressure solubility of CO2 in Thymol - Decanol based hydrophobic deep eutectic solvent and its binary mixtures with ethylene glycol

Deep eutectic solvents (DESs) as new classes of green solvents have been widely applied in many chemical and physical processes. Carbon dioxide (CO2) capturing by solvent is one of the interested issue which have been recently studied in DESs. This work includes the experimental results as well as the molecular dynamics (MD) simulation data of the solubility of CO2 in Thymol - Decanol as a hydrophobic DES and its binary mixtures with ethylene glycol (EG). The solubility of CO2 was measured at different compositions of binary solvent mixture under pressures 0.1–0.6 MPa at temperature range of 298–318 K. Experimental results showed that the CO2 solubility increased with increasing of DES molar fraction. The dependence of Henry's constant on solvent composition was investigated using preferential solvation model. Results showed that CO2 was preferentially solvated by DES molecules in binary solvent mixtures. In addition, MD simulations confirmed result of the experimental finding and preferential solvation model.

Phase diagrams of binary ionic mixtures and white dwarf cooling

ABSTRACT Phase diagrams of fully ionized binary ionic mixtures are considered within the framework of the linear mixing formalism taking into account recent advances in understanding quantum one-component plasma thermodynamics. We have followed a transformation of azeotropic phase diagrams into peritectic and eutectic types with increase of the charge ratio. For solid 12C/16O and 16O/20Ne mixtures, we have found extensive miscibility gaps. Their appearance seems to be a robust feature of the theory. The gaps evolve naturally into two-solid regions of eutectic phase diagrams at higher Z2/Z1. They do not depend on thermodynamic fit extensions beyond their applicability limits. The gaps are sensitive to binary mixture composition and physics, being strongly different for C/O and O/Ne mixtures and for the three variants of corrections to linear-mixing solid-state energies available in the literature. When matter cools to its miscibility gap temperature, the exsolution process takes place. It results in a separation of heavier and lighter solid solutions. This may represent a significant reservoir of gravitational energy and should be included in future white dwarf (WD) cooling simulations. Ion quantum effects mostly resulted in moderate modifications; however, for certain Z2/Z1, these effects can produce qualitative restructuring of the phase diagram. This may be important for the model with 22Ne distillation in cooling C/O/Ne WD proposed as a solution for the ultramassive WD cooling anomaly.

Experimental investigation of pile characteristics of non-spherical particles mixtures: pile height and angle of repose

An angle of repose is defined as the steepest angle of a conical pile that is naturally formed when a bulk of particulate solid is poured onto a flat surface. It has been considered as one of the important properties in characterizing granular material due to its effectiveness in determining flowability of granular, pile profile in an opaque container, and granular transportation system. Since the angle of repose is sensitive to the shape of individual particles, investigations through experiments and simulations for various forms of particles have been carried out. However, most of them were performed under homogeneous particle systems. While in practical situations, granular mixtures consisting of a variety of particle shapes are commonly employed. This study presents an experimental investigation of angles of repose resulting from a mixture of two types of non-spherical particles with different values of roundness. Experiments have been carried out with different compositions and have been repeated five times to ensure their reproducibility. The results show that the angle of repose linearly corresponds to the granular composition, where the coefficient of determination is ~0.95. Therefore, the effect of granular composition in binary mixtures on the characteristics of the resulting pile has been demonstrated in this study.

Adsorption Properties and Composition of Binary Kolliphor Mixtures at the Water-Air Interface at Different Temperatures.

The studies on the adsorption properties and composition of the adsorbed monolayer at the water–air interface of the binary Kolliphor® ELP (ELP) and Kolliphor® RH 40 (RH40) mixtures based on the measurements of the surface tension (γLV) of their aqueous solution in the temperature range from 293 to 318 K were carried out. The γLV isotherms were described by the exponential function of the second order and the Szyszkowski equation as well as predicted by Fainerman and Miller equation. The obtained γLV isotherms were analyzed using the exponential function of the second order, the Szyszkowski, Fainerman and Miller as well as independent adsorption equations. The γLV isotherms were also used for determination of the Gibbs surface excess concentration of RH40, ELP and their mixture (Γ) at the water–air interface as well as the mixed monolayer composition. Based on Γ and the constant a in the Szyszkowski equation, the standard thermodynamic functions of adsorption were considered. From the consideration dealing with the γLV isotherms obtained by us, it results, among others, that these isotherms for the non-ideal solution of macromolecular surfactants mixture can be predicted using the Fainerman and Miller equation. From this consideration, it also results that a simple method proposed by us, based on the isotherms of RH40 and ELP, allows us to predict the composition of their mixed monolayer in the whole concentration range of RH40 and ELP in the bulk phase.

VLE measurement of binary systems containing imidazolium ionic liquids and water or ethanol

Experimental VLE data for binary systems of ethanol or water with three 1-ethyl-3-methylimidazolium ionic liquids (ILs) containing different anions were measured at normal pressure using the Siwoloboff procedure. ILs selected in this study were those that appear to be suitable for the ethanol−water mixture separation by extractive distillation. Measured vapor–liquid equilibria were described by the extended Raoult's law with components activity coefficients calculated using the NRTL equation. Detailed analysis of the VLE data is presented in form of equilibrium diagrams, variation of activity coefficients with mixture composition and thermodynamic consistency tests. Experimental t–x data were measured within a wider range of the binary mixture compositions and compared to those found in literature. Boiling point temperature measurement of binary mixtures (adapted Siwoloboff procedure) provided comparable results to those obtained applying conventional methods of VLE estimation (circulation method, ebulliometric measurement, etc.). Reliability and thermodynamic consistency of experimental data obtained using the adapted Siwoloboff procedure for high ILs’ content (high temperature) were affected by the accuracy of the temperature measurement. However, the trend of these experimental data is useful for VLE description in concentration regions where usually only coarse extrapolation is applied. Experimental data obtained for a wide binary mixture composition range (IL content of more than 70 mole%) seem to be more suitable for binary and ternary VLE description in separation equipment simulations, e.g. extractive distillation columns.

Binary mixtures containing imidazolium ionic liquids: properties measurement

Abstract Densities and transport properties (dynamic viscosity) of pure imidazolium ionic liquids 1-butyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium dicyanamide and their binary mixtures with water and ethanol were measured within the temperature range of 293.15—333.15 K. Obtained experimental data were used to calculate excess molar volume and viscosity deviation. For the chosen binary mixtures, variations of excess molar volume, partial molar volumes of mixture components and of the viscosity deviation with the binary mixture composition were correlated using the Redlich-Kister equation. In addition, variation of viscosity with the binary mixture composition and temperature was fitted using the Jouyban-Acree model.

Modeling of transport properties of binary mixtures including ionic liquids based on their experimental estimation

Abstract Transport properties of selected imidazolium ionic liquids (1-ethyl-3-methylimidazolium acetate, [emim][ac], and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [bmim][triflate]) as well as of binary mixtures of these ILs with water and ethanol were estimated experimentally. Density data were obtained within the temperature range of 293.15—333.15 K and used for the excess molar volume calculations. For the binary mixtures comprising selected ionic liquids and water/ethanol, partial molar volumes of mixture components were computed and the excess molar volume variation with the mixture composition was correlated using the Redlich-Kister equation. Dependence of viscosity on the binary mixture composition and temperature was described using the Jouyban-Acree model. These data form a base for the assessment of OPEX connected with transportation of mixtures containing these ionic liquids.

A two‐point calibration method for quantifying organic binary mixtures using secondary ion mass spectrometry in the presence of matrix effects

Quantification of the composition of binary mixtures in secondary ion mass spectrometry (SIMS) is required in the analyses of technological materials from organic electronics to drug delivery systems. In some instances, it is found that there is a linear dependence between the composition, expressed as a ratio of component volumes, and the secondary ion intensities, expressed as a ratio of intensities of ions from each component. However, this ideal relationship fails in the presence of matrix effects and linearity is observed only over small compositional ranges, particularly in the dilute limits. In this paper, we assess an empirical method, which introduces a power law dependence between the intensity ratio and the volume fraction ratio. A previously published physical model of the organic matrix effect is employed to test the limits of the method and a mixed system of 3,3′‐bis(9‐carbazolyl) biphenyl and tris(2‐phenylpyridinato)iridium (III) is used to demonstrate the method. This paper introduces a two‐point calibration, which determines both the exponent in the power law and the sensitivity factor for the conversion of ion intensity ratio into volume fraction ratio. We demonstrate that this provides significantly improved accuracy, compared with a one‐point calibration, over a wide compositional range in SIMS quantification and with a weak dependence on matrix effects. Because the method enables the use of clearly identifiable secondary ions for quantitative purposes and mitigates commonly observed matrix effects in organic materials, the two‐point calibration method could be of significant benefit to SIMS analysts.

Implementation of Exp-6 potential function in thermodynamic modeling of clathrate hydrates phase equilibria

Accurate modeling of clathrate hydrates phase behaviors is of significant importance to petroleum industry. It is well known that accurate consideration of the cavity force field can lead to more accurate predictions of incipient conditions of clathrate hydrates. Intermolecular repulsive force is the dominant force in cavity space that is a determinative factor in taking the guest–host interactions into account. As the result, further modifications in potential function part of van der Waals and Platteeuw (vdWP) solid solution theory could improve the model accuracy. In this study, the influence of repulsive force between guest–host molecules in hydrate cavities was investigated through replacing Kihara potential function by Exp-6 potential function. The vdWP model equations were derived based on new potential function. The pair potential parameters were regressed using equilibrium dissociation conditions data of simple hydrates of natural gas constituents. The determination performances of Kihara and Exp-6 potential functions were compared in aspects of incipient hydrate dissociation conditions and hydrate composition of binary hydrate formers and mixtures of natural gas systems. The results show a promising improvement in vdWP model in case of binary hydrate systems, while the accuracy of the model does not change dramatically in case of natural gas hydrate system. This is due to cancellation of changes in Gibbs energy of occupation for different guest species and the natural gas composition.

Preparation of Binary Mixed Inorganic Hydrate

In this paper, 54 binary mixed inorganic hydrates composed of Na2SO4·10H2O, Na2CO3·10H2O, CH3COONa·3H2O and MgSO4·7H2O were prepared, and try to research their reasonable and feasible preparation methods. The results show that the thermogravimetric ratio of binary mixtures varies with the composition and proportion of binary mixtures. There is evaporation of water in the mixtures preparation process, so appropriate deionized water should be added to supplement the evaporated water in the mixtures preparation of phase change materials.

Removal of hydrogen sulfide from a binary mixture with methane gas, using IRMOF-1: a theoretical investigation.

The natural gas is mainly composed by methane, ethane, propane, and contaminants. Among these contaminants, the H2S gas has some specific characteristics such as its toxicity and corrosion, besides reducing the combustion power efficiency of natural gas. In this context, metal-organic frameworks appear as promising materials for purification of natural gas by adsorption, due to their large surface area and pore volume. In this work, Grand Canonical Monte Carlo method was used to study the adsorption and separation of CH4:H2S mixture by IRMOF-1. The adsorption isotherms were computed for the pure components, and at different compositions of binary mixture (90:10, 75:25, 50:50, 25:75, and 10:90). Interaction energy obtained with the semiempirical method confirmed that the inorganic unit is the preferred site for CH4 and H2S adsorption. Moreover, in a gas mixture with 50:50 proportion of CH4:H2S mixture, methane adsorbs preferentially in the inorganic unit only at pressures close to 20bar. Non-covalent interaction (NCI) analyses indicated that the interactions involving H2S are more effective than that for CH4, due to an electrostatic character in the H2S interaction. The simulations also showed that the separation of gases occurs in all compositions and pressures studied, suggesting that IRMOF-1 has a promising potential for this application.