Homogeneous Liquid Region Research Articles

Application of a new equation of state to energy carriers

A new equation of state (IR EOS) recently reported for liquids and gases has been utilized to predict the densities of some energy carriers at different temperatures, pressures. The ability of IR EOS is examined by comparing its results with experimental data for some energy carriers in homogeneous gas, homogeneous liquid and gas–liquid transition region from low to very high pressures. The IR EOS gives excellent results in homogenous gas and homogeneous liquid region while its predictions in gas–liquid transition have more deviations. The average absolute deviation between calculated and experimental densities for 968 data points of 12 energy carriers is 0.33% over the entire range of data with a maximum pressure of 1000 MPa.

Development of a special single-sinker densimeter for cryogenic liquid mixtures and first results for a liquefied natural gas (LNG)

A special densimeter has been developed for accurate density measurements of liquid mixtures at cryogenic temperatures, e.g., liquefied natural gas (LNG). It covers the density range from (10 to 1000)kg·m−3, thus enabling density measurements in the supercritical region, in the homogeneous liquid region, along the saturated liquid line as well as in the homogeneous gas region. The apparatus is designed for measurements over a temperature range from (90 to 300)K at pressures up to 12MPa. The densimeter is based on the Archimedes (buoyancy) principle and is a single-sinker system incorporating a magnetic suspension coupling. The density can be obtained directly without the need for calibration fluids. The relative combined expanded uncertainty (k=2) for density measurements in the homogeneous liquid region (including the contribution resulting from the uncertainty of the sample gas analysis) was estimated to be 0.044%. First results for a synthetic five-component LNG mixture were obtained at the temperatures T=(105, 115, 120, 125, and 135)K with pressures up to 8.1MPa. The results were compared to the GERG-2008 reference equation of state for natural gases, which represents the experimental values within 0.06%.

Modifying GMA equation of state for description of (P, ρ, T) relation of gas and liquids over an extended pressure range

The main concern of this paper is on the improvement of the GMA equation of state (Fluid Phase Equilibr. 230 (2005) 170) which has been used for density calculation of components in liquid region with excellent accuracy. However, the GMA equation of state cannot predict the density of components in either the gas or gas-liquid transition region. The GMA equation of state is based on intermolecular potential energy; therefore, the potential energy of the GMA equation of state is corrected and an equation of state is obtained. The final form of the new equation of state is a regularity between (Z−1)v 3 and ρ for all temperatures, which is based on modified Lennard-Jones potential (9, 6, 3). The capability of the new equation of state is examined by comparing the results with experimental data in homo- geneous gas, homogeneous liquid and gas-liquid transition region from low to very high pressures. The new equation of state gives excellent results in homogeneous gas and homogeneous liquid region, while the predictions in the gas-liquid transition have more deviations. The average absolute deviation between calculated and experimental densities for 1979 data points of 24 components is 0.25% over the entire range of data with a maximum pressure of 1,000 MPa.

Effect of Al2O3 or MgO on Liquidus Line in the FeOX Corner of FeOX-SiO2-CaO System at 1523 K under Various Oxygen Partial Pressures

Abstract. The liquidus line in the FeO X corner of FeO X -SiO 2 -CaO system and the effect by adding Al 2 O 3 or MgOto this plain system on the liquidus line were experimen-tally investigated at 1523 K in a wide range of oxygen par-tial pressure between about 10 12 and about 10 4 atm andfor given (mass% CaO =mass% SiO 2 / ratios in the systembetween 0 and about 1. It was found for the plain sys-tem that the liquidus lineremarkably shifted toward the lowFeO X -content region when the partial pressure of oxygenwas increased from 10 10 to 10 8 atm. It was clari ed thatthe addition of Al 2 O 3 made the homogeneous region wideonlyinastronglyreducingatmospherewhiletheadditionofMgO made the homogeneous liquid region remarkably nar-row at all the oxygen partial pressures and all the (mass%CaO =mass% SiO 2 / ratios investigated in the study.Keywords. Liquidus line, FeOx-SiO 2 -CaO-Al 2 O 3 system,FeOx-SiO 2 -CaO- MgO system, oxygen partial pressure.PACS ® (2010). 82.60.Lf.1 IntroductionThe FeO

Phase relations in the Cu2Te–Al2Te3 semiconductor system

The T-x phase diagram of the Cu2Te–Al2Te3 semiconductor system was achieved experimentally using 24 different mixtures of the binary compounds. The results of X-ray powder diffraction, differential thermal analysis, and electron microprobe analysis are presented. It was established that only one ternary compound CuAlTe2 exists in this system crystallizing in the tetragonal structure of chalcopyrite with lattice constants at room temperature a = 6.035(5) and c = 11.94(1) A. The maximal homogeneity region of this compound was discovered being limited by compositions with 0.474 and 0.544 molar part of Al2Te3 at 673 K. CuAlTe2 decomposes peritectically at 1,183 K to (Cu2Te)0.97(Al2Te3)0.03 alloy with the structure of Cu2Te and liquid with the composition close to (Cu2Te)0.40(Al2Te3)0.60 which transforms into homogeneous liquid region at 1,240 K.

Cationic surfactant-based polyfluorate salts: Phase separation and analytical applications in the extraction and preconcentration of ionic species prior to liquid chromatography

The liquid–solid phase separation originating from the formation of cationic surfactant-based polyfluorate salts (CSBPS) has been explored for extracting and preconcentrating ionic species. Two cationic surfactants were tested; one with aliphatic hydrocarbon tail [Cetyltrimethylammonium bromide (CTAB)]and the other containing a heterocyclic ring [Hexadecylpyridinium bromide (HPyBr)]. Phase separation possibility was investigated with the use of hexafluorophosphates (PF 6 −) and tetrafluoroborates (BF 4 −). The effect of added acid, base and salt on the phase separation and analyte extraction was also investigated. In all cases the obtained phase diagrams consisted of two regions: a homogeneous liquid region and a solid–liquid region. Analytes of hydrophilic and hydrophobic nature such as amines, amino acids and organic chromophores were used as test compounds in both their anionic and cationic forms. The respective recoveries ranged from over 90% for anionic species and in the proximity of 50% for cationic species, remaining below 20% for neutral species. Extracts from alkaline aqueous and plasma samples spiked with tyrosine and phenylalanine were also subjected to HPLC separation with UV detection with satisfactory results. On line application was also enabled using a flow through-solid phase extraction-HPLC hyphenated apparatus, thus adding the element of automatization and increased reproducibility.

High Temperature Phase Relations in FeO<I><SUB>X</SUB></I>(<I>X</I>=1 and 1.33)–CaO–SiO<SUB>2</SUB> Systems under Various Oxygen Partial Pressure

As a fundamental study of slags in metallurgical processes, liquidus lines in the FeO(wustite)-CaO-SiO 2 and Fe 3 O 4 (spinel)-CaO-SiO 2 systems were determined at temperatures between 1573 and 1673 K and partial pressures of oxygen between 10 - 4 and 36Pa using a quenching method with a crucible of platinum foil. It was found that the two phases (solid wustite and liquid) region in the FeO-CaO-SiO 2 system (1573 K) increased remarkably by changing the partial pressure of oxygen from 10 - 4 to 10 - 3 Pa. It was also found that the two phases (solid spinel and liquid) region in the Fe 3 O 4 -CaO-SiO 2 system (1573 K) at PO 2 of 10 - 2 Pa was a little larger than that in the FeO-CaO-SiO 2 system at PO 2 of 10 - 3 Pa but it was extended considerably when the oxygen pressure was increased to 10 - 1 Pa. However, the two liquids region did no change too much in the range of oxygen pressure above 10 - 1 Pa even though the liquidus line became almost parallel to the Fe 3 O 4 -CaO axis in the ternary diagram when the oxygen pressure was increased. Furthermore, it was found that the two phase region in the Fe 3 O 4 -CaO-SiO 2 system at PO 2 of 10 - 1 Pa decreased remarkably with increasing temperature. On the basis of the obtained and reported data, the homogeneous liquid regions in the FeO x -CaO-Si0 2 systems (1573K) at PO 2 of 10 - 3 Pa, 10 - 1 Pa and in air were compared.

Hydrodynamics and mass transfer in heterogeneous distillation with sieve tray column

Hydrodynamics and separation performance of a sieve tray column in heterogeneous distillation are studied experimentally under total reflux conditions. A correlation for clear liquid height in the heterogeneous liquid region is obtained by modifying the correlation of the homogeneous systems. The volumetric dimensionless diffusion fluxes in the heterogeneous liquid region are smaller than those in the homogeneous liquid region. This may be due to the mass transfer resistance in the liquid phases. In order to examine the effect of liquid-phase resistance on separation performance, a simulation is carried out by either considering or neglecting the liquid-phase resistance. The simulation shows that the liquid-phase resistance affects the vapor-phase concentration driving forces, volumetric diffusion fluxes and convective mass flux in the heterogeneous liquid region. It also shows that the predicted top vapor concentrations and flow rate are in reasonable agreement with the experimental data in the heterogeneous liquid region by considering the liquid-phase mass transfer resistance.

Sulfide Capacity and Phase Equilibria of MnO-TiO2-MnS System at 1723 K.

The sulfide capacity and the activity of MnO in the MnO-TiO 2 system were measured at 1 723 K. Also, the phase equilibria of the MnO-TiO 2 -MnS system were estimated by measuring the solubility of MnS in the melts. The thermodynamic behavior of MnO and TiO 2 in the MnO-TiO 2 system exhibits a negative deviation from ideality at 1 723 K. The sulfide capacity increases and the activity coefficient of MnS decreases with increasing MnO content in the MnO-TiO 2 system. The solubility of MnS in the MnO-TiO 2 system increases with increasing MnO content up to about 50 mol%, followed by nearly constant value of about 80 mass% MnS. The solubility of MnS equilibrated with MnO is in good correspondence with the value obtained from the phase diagram of the MnO-MnS binary system. Compared with the phase diagram of the MnO-SiO 2 -MnS system, a homogeneous liquid region in the MnO-TiO 2 -MnS system is found to be wider at the same temperature. The activity of MnS increases with increasing MnS content at a fixed MnO/TiO 2 ratio in the MnO-TiO 2 -MnS system. Also, the activity slightly decreases with increasing TiO 2 content at a fixed MnS/MnO ratio, whilst MnS activity rapidly decreases by increasing the content of MnO at a constant TiO 2 /MnS ratio.

An Acid-Induced Phase Cloud Point Separation Approach Using Anionic Surfactants for the Extraction and Preconcentration of Organic Compounds

The acid-induced liquid−liquid phase separation of anionic surfactants in aqueous solutions, and its applicability to cloud point extraction methodology, were examined. The phase diagrams obtained (e.g., [HCl] vs [surfactant]) consisted of three regions: a homogeneous liquid region, two coexisting isotropic phases, and a solid region. The breadth of each region was found to depend on the surfactant structure. The behavior of each phase was also examined in relation to temperature and added salts. The anionic surfactants investigated were sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonic acid (SDBSA), sodium dodecanesulfonic acid (SDSA), and sodium dioctylsulfosuccinate (Aerosol OT). The use of anionic surfactant-mediated phase separations provided very high extraction efficiencies (80−100%) for pyrene in aqueous samples and various PAHs in a certified reference material (dried sewage sludge). The preconcentration factor achieved was found to be a function of both surfactant and acid concentrati...

Homogeneous and Heterogeneous Distillation of Ethanol-Benzene-Water System by Packed Column with Structured Packing.

An experimental study is made on mass transfer in a packed distillation column with the structured packing covering homogeneous and heterogeneous liquid regions for an ethanol-benzene-water system under total reflux conditions. The vapor phase diffusion fluxes obtained in the homogeneous liquid region agree well with the correlation derived from an acetone-ethanol system by Olano et al. (1995). On the other hand, the observed diffusion fluxes in the heterogeneous liquid region exhibit wide scattering, which may be due to the neglect of the liquid phase resistance and the assumption of three-phase equilibrium at the vapor-liquid interface in this experimental analysis.In order to examine the effect of liquid phase resistance on the separation performance in the packed distillation column, its simulation is also carried out by considering or neglecting the liquid phase resistance. The liquid phase resistance has much influence on the vapor phase concentration driving force, and then the diffusion and convective mass flux in the heterogeneous liquid region. The top concentrations and reflux flow rates predicted by considering the liquid phase resistance agree reasonably well with the experimental data in the heterogeneous liquid region. On the contrary, the effect of the liquid phase resistance on the separation performance in the homogeneous liquid region is very small as generally accepted.

5559159 Process including depolymerization in polyester reactor for recycling polyester materials : Sublett Bobby; Connell Gary Kingsport, TN, United States assigned to Eastman Chemical Company

Measurements of (P gr, T) for pure dichlorodifluoromethane (R12) and for pure chlorodifluoromethane (R122) were carried out on four isotherms (150 K, 200 K, 250 K, and 300 K) in the homogeneous liquid region from the vapour pressure up to pressures of 8 MPa. Measurements in the homogeneous gas region were performed on three isotherms (260 K, 300 K, and 330 K) for R 12 andon four isotherms (250 K, 270 K, 300 K, and 330 K) for R 22 up to the corresponding vapour pressure. Furthermore, the saturated-liquid densities of R12 and of R22 were measured in the temperature range from 120 K to 340 K along with the vapour pressure; the vapour-pressure measurements, however, were started only at 180 K. Using the experimental results from the gas region, the saturated-vapour densities and the second virial coefficients were also determined. The uncertainties of the homogeneous liquid densities and of the saturated-liquid densities were estimated to be <|0.0002 · ρ| and the uncertainties of the gas densities ρ > 10 km · m−3 to be <|.0003 · ρ|. The new measurements are compared with the experimental results of previous workers.

NaO&lt;SUB&gt;0.5&lt;/SUB&gt;-CO&lt;SUB&gt;2&lt;/SUB&gt;-FeO&lt;SUB&gt;1.5&lt;/SUB&gt;系スラグの熱力学

Thermodynamic properties of NaO0.5-CO2-FeO1.5 slag have been investigated for the application of sodium carbonate slag to the elimination of Fe from molten copper. The activities of NaO0.5 and Na(CO3)0.5 were measured by the EMF method, using beta′′-alumina as a solid electrolyte, for various partial pressures of CO2 at 1423 to 1523 K. There is a stable solid compound NaFeO2 in this system, and the solubility measurement of this compound into sodium carbonate melt at 1523 K revealed that the solubility is very limited and controlled by the partial pressure of CO2. The dissolution reaction seems to proceed according to the following reaction and Fe exists as FeO33− anion in the sodium carbonate-based melt.(This article is not displayable. Please see full text pdf.) \ oindentThe standard free energy change for the following reaction:(This article is not displayable. Please see full text pdf.) \ oindentwas also determined by the EMF method as:(This article is not displayable. Please see full text pdf.) \ oindentThe activity of FeO1.5 in the (solid NaFeO2+liquid) two phase region could be calculated from the activity of NaO0.5 via the above equilibrium relation. Distribution equilibrium measurements were also conducted for Fe between the slag and molten copper at 1523 K not only to confirm the calculated results but also to determine the activity of FeO1.5 in the homogeneous liquid region of the slag. The activity coefficient of FeO1.5 in the homogeneous liquid region has a constant value for a constant CO2 partial pressure, independent of the concentration.

NaO&lt;SUB&gt;0.5&lt;/SUB&gt;-CO&lt;SUB&gt;2&lt;/SUB&gt;-SnO&lt;SUB&gt;2&lt;/SUB&gt;系スラグの熱力学と本系スラグ-溶銅間のSnの分配比の推算

In view of the application of sodium carbonate slag to the elimination of Sn from molten copper, the thermodynamic properties of NaO0.5-CO2-SnO2 slag have been studied by conducting the following experiments:(1) Activities of NaO0.5 in the slag were determined by the EMF method using β′′-alumina as a solid electrolyte over the composition range of 1>N≥0.795{N=nNa+(nNa⁄nSn),n:the number of moles}under the partial pressures of CO2 of 0.001∼0.08 MPa at 1423∼1523 K. It was found that the activity of NaO0.5 did not depend on the slag composition for the constant partial pressure of CO2 and the slag was saturated with Na2SnO3(s).(2) Then the solubility of Na2SnO3(s) into the sodium carbonate melt was measured under the various partial pressures of CO2 at 1523 K. With decreasing the partial pressure of CO2 the solubility increased, but the partial pressure of oxygen had no effect.(3) Activities of SnO2 were determined by the distribution equilibrium measurements for Sn between the Na2SnO3(s)-saturated slag and molten copper. From the activity of SnO2 combined with that of NaO0.5, the standard free energy change for the following reaction was determined as:(This article is not displayable. Please see full text pdf.) \ oindentThe activity of SnO2 in the homogeneous liquid region of the slag was also evaluated by the distribution equilibrium measurements.Based on the results obtained, the distribution ratios of Sn between the slag and molten copper were estimated. The ratios decrease with decreasing SnO2 content in the Na2SnO3(s)-saturated slag. The higher oxygen partial pressure and the lower CO2 partial pressure are more preferable for the removal of Sn from molten copper.

Measurements of the (pressure, density, temperature) relations of dichlorodifluoromethane (R12) and of chlorodifluoromethane (R22) in parts of the homogeneous gas and liquid regions and on the coexistence curve

Measurements of (P gr, T) for pure dichlorodifluoromethane (R12) and for pure chlorodifluoromethane (R122) were carried out on four isotherms (150 K, 200 K, 250 K, and 300 K) in the homogeneous liquid region from the vapour pressure up to pressures of 8 MPa. Measurements in the homogeneous gas region were performed on three isotherms (260 K, 300 K, and 330 K) for R 12 andon four isotherms (250 K, 270 K, 300 K, and 330 K) for R 22 up to the corresponding vapour pressure. Furthermore, the saturated-liquid densities of R12 and of R22 were measured in the temperature range from 120 K to 340 K along with the vapour pressure; the vapour-pressure measurements, however, were started only at 180 K. Using the experimental results from the gas region, the saturated-vapour densities and the second virial coefficients were also determined. The uncertainties of the homogeneous liquid densities and of the saturated-liquid densities were estimated to be 10 km · m−3 to be