Static Apparatus Research Articles

Bubble Point Pressure and Some Dielectric Properties of Propane+Ethanol Liquid Mixture at 303.2 K

Bubble point pressure and dielectric spectra of propane+ethanol liquid mixtures were measured at 303.2 K. The bubble point pressure was measured by use of a static type apparatus. The experimental pressure increased with increase in the mole fraction of propane, and the tendencies were well correlated with NRTL equations. The dielectric constants decreased with the mole fraction of propane. Otherwise the dielectric relaxation times showed convex shapes for the mole fraction of propane. The excess dielectric constants and the excess inverse dielectric relaxation times showed negative values over the whole range of the propane concentration. These phenomena suggested that hydrophobic interactions and dipole-dipole interactions play important roles in determining the dielectric properties of propane+ethanol liquid mixtures at the experimental temperature and pressure.

CO2 + n-dodecane + 3,7-dimethyl-1-octanol: High pressure experimental phase equilibria data and thermodynamic modelling

New high pressure VLE data for the ternary mixture CO2+n-dodecane (nC12)+3,7-dimethyl-1-octanol (37DM1O) are presented. A static apparatus with online analysis was used to measure phase compositions at 35, 55 and 75°C, and pressures between 68 and 157bar. In the high-nC12 region the mixture displayed enhanced solubility, presenting as a pinched two phase band and s-shaped liquid phase curves. Relative solubility, an indicator of fractionation sharpness, increased with 37DM1O content and the 75:25 nC12:37DM1O mixture cannot be separated using CO2. RK-ASPEN, SR-POLAR, PR-BM and PC-SAFT models were evaluated for their ability to correlate these data. RK-ASPEN and PC-SAFT models provided the best and worst correlation of equilibrium pressures with respective percentage average absolute deviations of 3.1% and 8.5%. RK-ASPEN model was impressive in its ability to capture the co-solubility pinch seen for the 75:25 nC12:37DM1O mixture and the resultant s-shaped liquid phase complexity.

Flowfield and Performance Analysis of a Three-Dimensional TBCC Exhaust Nozzle

Compared to other engines, turbine-based combined cycle (TBCC) engine is one of the most suitable propulsion systems for hypersonic vehicle. Because of its fine reusability, wide flight envelope, and safety margins, TBCC engine is becoming a more and more important hotspot of research. In this paper, a three-dimensional (3D) over–under TBCC exhaust system is designed, simulated, and the results are discussed, wherein the ramjet flowpath is designed by the quasi-two-dimensional method of characteristics (MOC). A new scheme of rotating around the rear shaft is proposed to regulate the throat area of turbine flowpath. Cold flow experiments are conducted to gain a thorough and fundamental understanding of TBCC exhaust system at on and off-design conditions. To characterize the flow regimes, static pressure taps and schlieren apparatus are employed to obtain the wall pressure distributions and flowfield structures during the experiments. Detailed flow features, as well as the thrust performance, are simulated by the computational fluid dynamics (CFD) method. Both the numerical and experimental results show that the TBCC exhaust nozzle in this study can provide sufficient thrust during the whole flight envelop despite a little deterioration at the beginning of the mode transition. The research provides a new and effective scheme for the exhaust system of TBCC engine.

Phase equilibrium measurements and thermodynamic modeling of binary mixtures containing a diesel compound n-dodecane + biodiesel compounds: Ethyl dodecanoate and ethyl octanoate

The vapor pressures of two binary systems ethyl dodecanoate (1)+n-dodecane (2) and ethyl octanoate (1)+n-dodecane (2), were measured by means of a static apparatus at temperatures between 373.15K and 453.15K. The data were correlated with the Antoine equation. From these data, the molar excess Gibbs energies GE were obtained with Barker’s method and fitted to the Redlich-Kister equation. The binary mixture (ethyl octanoate (1)+n-dodecane (2)) exhibits maximum azeotropic behavior. Positive values of the excess Gibbs energy are obtained for all the investigated constant temperatures and over the whole composition range. The data were also correlated by using Wilson equation and good results were obtained in the prediction of the total pressure and thermodynamic excess properties; however deviations were observed with respect to the experimental and predicted GE, using modified UNIFAC (Dortmund) group contribution model. Additionally, the NRTL model was applied to regress the experimental GE. The investigated systems were successfully represented by the NRTL model.

Isothermal Vapor Pressures of Three Binary Systems: n-Tetradecane + Methyl Dodecanoate, Methyl Tetradecanoate, or Methyl Hexadecanoate between 353.15 and 453.15 K

Isothermal vapor pressures of three binary systems, methyl dodecanoate (1) + n-tetradecane (2); methyl tetradecanoate (1) + n-tetradecane (2); and methyl hexadecanoate (1) + n-tetradecane (2), were measured by means of a static apparatus at temperatures between 353.15 and 453.15 K. The data of the pure components were correlated by the Antoine equation. A maximum azeotropic behavior is observed for the binary mixture, methyl dodecanoate (1) + n-tetradecane (2). The molar excess Gibbs energies GE were deduced from Barker’s method by fitting the experimental points through Redlich–Kister equation. The NRTL and UNIQUAC models were applied to regress the experimental vapor liquid equilibrium (VLE). The investigated systems were successfully represented by the two models.

New Static Apparatus for Vapor Pressure Measurements: Reconciled Thermophysical Data for Benzophenone

A newly developed static apparatus, capable of measuring the vapor pressure in the temperature range 273–368 K and in the pressure range 0.1–1333 Pa, is presented. The apparatus was calibrated by measuring the vapor pressure of recommended reference materials, naphthalene, n-decane, and ferrocene, and thoroughly tested. Subsequently, new vapor pressure data for benzophenone were measured in the temperature range 293–365 K with the aim to establish revised thermophysical data for this compound. Although benzophenone is another material recommended as the reference material for sublimation pressure and enthalpy measurements, the published sublimation thermodynamic data show a significant spread, and the recommendation was made with reservations which involved a reported metastable crystalline phase. We clarify this point based on reviewing the literature reporting the phase behavior and crystallographic studies and an extensive study on the polymorphic behavior of benzophenone performed in the present work....

Experimental vapor pressures (from 1 Pa to 100 kPa) of six saturated Fatty Acid Methyl Esters (FAMEs): Methyl hexanoate, methyl octanoate, methyl decanoate, methyl dodecanoate, methyl tetradecanoate and methyl hexadecanoate

Vapor pressures of six saturated Fatty Acid Methyl Esters (FAMEs), methyl hexanoate (or methyl caproate), methyl octanoate (or methyl caprylate), Methyl decanoate (or methyl caprate), methyl dodecanoate (or methyl laurate), methyl tetradecanoate (or methyl myristate), and methyl hexadecanoate (or methyl palmitate) were measured from 1Pa to 100kPa and at temperature range between 262 and 453K using a static apparatus. The experimental data (P-T) were compared with the available literature data.

Phase equilibrium properties of binary mixtures containing a diesel compound (n-dodecane) + biodiesel compounds (ethyl hexanoate, ethyl decanoate and ethyl tetradecanoate)

The vapor pressures of three binary systems ethyl hexanoate (1) + n-dodecane (2), ethyl decanoate (1) + n-dodecane (2) and ethyl tetradecanoate (1) + n-dodecane (2) were measured by means of a static apparatus at temperatures between 373.15 and 453.15 K. The data were correlated with the Antoine equation. From these data, the molar excess Gibbs energies G E were obtained with Barker’s method and fitted to the Redlich–Kister equation. The excess Gibbs energy is positive for all the investigated constant temperatures and over the whole composition range. The Wilson equation was used and good results were obtained in the prediction of the total pressure and thermodynamic excess properties; however, deviations were observed with respect to the experimental and predicted G E, using UNIFAC (Dortmund) group contribution model.

Liquid–vapor equilibria of pure and aqueous solutions of diethylenetriamine or dipropylenetriamine

Vapor pressures of pure and aqueous diethylenetriamine (DETA) and dipropylenetriamine (DPTA) were measured by means of a static apparatus at temperatures between (283 and 363) K. The data were correlated with the Antoine equation and fitted to Redlich–Kister equation using Barker's method. Additionally, the NRTL, UNIQUAC models were used to correlate total pressures.

Solubility of Ethene in n-Hexane and n-Heptane as Common Slurry-Phase Polymerization Solvents: Experimental Measurement and Modeling

To evaluate solvent performance, mass transfer calculation of gas–liquid phases and good prediction of catalyst activity and polymer product yield, precise experimental solubility data are required in slurry-phase ethene polymerization. The solubility of ethene in n-hexane and n-heptane as commercial solvent of ethene slurry-phase polymerization was measured at pressures from 0.18 to 1.6 MPa and temperatures ranging from 303 to 348 K. A static apparatus is used to measure the experimental data. The experimental data are modeled using Peng–Robinson cubic equation of state (PR CEOS) with vdW mixing rule with two adjustable parameters. The modeling results show the PR CEOS is capable to represent the experimental data well.

Phase equilibrium measurements and thermodynamic modeling of aqueous solutions of polyamines CO2 absorbents: 3-aminopropylmethylamine, 3-aminopropyldimethylamine and N,N-diethyl 1,3-propanediamine at temperatures from 273 K to 363 K

The vapor pressures of the pure components 3-aminopropylmethylamine (MAPA), 3-aminopropyldimethylamine (DMAPA) and N,N-diethyl 1,3-propanediamine (DEAPA) along with the binary mixtures (MAPA+water), (DMAPA+water) and (DEAPA+water) were measured by means of a static apparatus at temperatures between (273 and 363)K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (GE) were calculated for several constant temperatures, and fitted to a three parameters Redlich–Kister equation using the Barker’s method. Additionally, the NRTL and UNIQUAC models have been used for the correlation of the total pressure.

Vapor pressures and thermophysical properties of selected monoterpenoids

A thermodynamic study of selected monoterpenoids, geraniol, β-citronellol, and borneol, is presented in this work. The vapor pressure measurements were performed using two static apparatus over a wide temperature range from 273 to 363K. Liquid heat capacities were measured by Tian–Calvet calorimetry in the temperature interval from 258 to 355K. The phase behavior was investigated by DSC from 183K. The thermodynamic properties in the ideal-gas state were calculated by combining statistical thermodynamics and density functional theory (DFT) calculations. Calculated ideal-gas heat capacities and experimental data on vapor pressure and condensed phase heat capacity were treated simultaneously to obtain a consistent thermodynamic description.

Phase diagrams of binary systems containing tricyanomethanide-based ionic liquids and thiophene or pyridine—New experimental data and PC-SAFT modelling

Isothermal vapor–liquid equilibrium (VLE) phase diagram measurements for the binary systems composed of tricyanomethanide-based ionic liquids and thiophene or pyridine were carried out over the whole range of composition at temperature between (293.15 and 313.15) K using a static apparatus. Moreover, liquid–liquid equilibrium (LLE) phase diagrams for the investigated systems have been determined at atmospheric pressure using a dynamic method. The impact of the cation core structure (imidazolium, or pyridinium, or pyrrolidinium) on the both VLE and LLE has been discussed. Modelling of the investigated properties in terms of molecular-based equation of state, namely perturbed-chain statistical associating fluid theory (PC-SAFT), was performed. Pure-fluid parameters for ionic liquids were obtained from ambient pressure densities and the Hildebrand solubility parameters. Calculations of VLE and LLE employed binary corrections to common combining rules fitted to experimental activity coefficients of thiophene and pyridine reported previously in literature.

Measurement, correlation and prediction of isothermal vapor–liquid equilibria of different systems containing vegetable oils

Thermodynamic properties, in particular vapor–liquid equilibrium (VLE) data, are required for the development of reliable predictive models for systems with fatty compounds. Isothermal VLE data have been measured for mixtures of methanol, ethanol, or n-hexane with refined vegetable oils (soybean, sunflower and rapeseed) at 348.15K and 373.15K using a computer-driven static apparatus. The oils were characterized in terms of their fatty acid and corresponding triacylglycerol (TAG) compositions. For the mixtures containing vegetable oils and n-hexane a negative deviation from Raoult’s law was observed and a homogeneous behavior (no miscibility gap) was found, while the mixtures with alcohols exhibited positive deviation from ideal behavior and, in some cases, limited miscibility. On the basis of the composition of the studied vegetable oils, their relative van der Waals volume and surface area parameters were estimated by the Bondi method and their vapor pressure by a group contribution method developed by Ceriani and Meirelles [1]. The experimental VLE data were correlated together with available excess enthalpies (HE) and activity coefficients at infinite dilution (γi∞) data using the UNIQUAC model. For the fitting process the refined vegetable oil was treated as a single triacylglycerol (pseudo-component) which has the corresponding degree of unsaturation, number of carbon atoms and molar mass of the original oil composition. The overall-average errors (AAE) using UNIQUAC model are 4.46% for VLE, 7.07% for γi∞ and 5.80% for HE The experimental data were also compared with the predicted results using mod. UNIFAC (Dortmund) and an extension of this method proposed for triacylglycerols in a previous work was also tested.

Isothermal (vapor + liquid) equilibria for the binary mixtures of (propylene oxide + ethanol) and (propylene oxide + 1-propanol) at several temperatures

Isothermal (vapor+liquid) equilibrium data for the binary mixtures of (propylene oxide+ethanol) and (propylene oxide+1-propanol) were measured using a static apparatus at three different temperatures ranging from (303.15 to 333.15)K at an interval of 15K. The measured data were correlated using Peng–Robinson–Stryjek–Vera equation of state (PRSV EOS) combined with van der Waals one-fluid mixing rule for the vapor phase and with Wong-Sandler mixing rule involving a non-random two liquid (NRTL) model, universal quasi-chemical (UNIQUAC) model and Wilson model for the liquid phase. The experimental data are in good agreement with the correlation results.

「静止器における解析技術の最新動向」特集号によせて

「静止器における解析技術の最新動向」特集号によせて

静止器における解析技術の現状と今後の課題

静止器における解析技術の現状と今後の課題

A Comparison of Natural Depletion and Different Scenarios of Injection in the Reservoir From the Beginning of Oil Production

This research comprises natural depletion, associate, and CO2 gas injection with regard to asphaltene precipitation and permeability reduction. For the sake of achievement these goals experiments were undertaken by core flood and asphaltene static apparatus. Natural depletion was performed at 4500, 3050, 2250, 1450, and 900 Psig and it has been seen maximum amount of asphaltene precipitation located at saturation pressure. The results demonstrate that asphaltene precipitation during natural depletion was higher than CO2 and associate gas injection. Also it was seen asphaltene precipitation rate during CO2 and associate gas injection was lower than natural depletion. Based on results, amount of asphaltene precipitation was differing according to type of gas. The results of the study indicate asphaltene precipitation during CO2 injection was more than associate gas injection. Finally it was seen the permeability reduction during associate was less than CO2 and natural depletion for this kind of Iranian carbonate sample.

A Compositional Reservoir Simulation and Experimental Investigation of Asphaltene Onset Pressure

Asphaltene precipitation is one of the most common problems in many reservoirs and may lead to many safeties operational issues which affects on oil recovery; therefore, identifying start of asphaltene activation is known as a key parameter to control production efficiency. This study includes predicting onset pressure with Multiphase Flash test and compare its result with experimental data generated by Asphaltene Static Apparatus. Safety pressure was obtained by performing Multiphase Flash test for each component. In order to prevent adsorption, mechanical entrapment, and blockage, reservoir pressure must be higher than this safety pressure. SARA test is widely used to identify the fraction of crude oil that affect the asphaltene stability. IP143 standard test was used to measure precipitated asphaltene. Natural depletion test was designed at four steps, including 4400, 3000, 1550, and 1020 Psia and reservoir temperature is 205°F. It was seen that with decreasing pressure from reservoir pressure to saturation pressure asphaltene precipitation from PVT cell was increased and at pressures below saturation pressure with pressure reduction, asphaltene precipitations was decreased. Also it was concluded that above saturation pressure solubility model is dominant and below saturation pressure colloidal model is dominant. The results of IP143 show that initial content of asphaltene are 12.8%. SARA test result shows this kind of fluid located at unstable asphaltene precipitation region. Comparison of safety pressure between Multiphase Flash test and experimental data are investigated and discussed. Onset pressure of 18000 Pisa was obtained from Multiphase Flash test, which is in good agreement with experimental result.

Experimental and Modeling of the Propene Solubility in the Heptane and Methylbenzene Solvents

To estimate the amount of dissolved propene gas in various industrial solvents especially in the early time of polymerization in slurry-phase propene polymerization and consequently achieve real polymer productivity, the precise experimental solubility data are needed. The solubility of propene in methylbenzene and heptane was measured at pressures from (0.13 to 1.27) MPa and temperatures ranging from (313 to 359) K. A static apparatus is used to measure the experimental data. The experimental data are modeled using the Peng–Robinson cubic equation of state (PR CEOS) with the van der Waals (vdW) mixing rule with two adjustable parameters. The modeling results show that the PR CEOS is capable to represent the experimental data well.