Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 1. Sodium Sulfate

Abdulagatov, Ilmutdin M.; Mursalov, and Boris A.; Dvoryanchikov, V. I.

doi:10.1021/je0001227

Cited by 10 publications

(13 citation statements)

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“…In more complicated systems (for example, water + salt solutions with salt precipitation at high temperatures [43,44] or partially miscible liquids like water + hydrocarbon mixtures [42]) other Table II. Experimental Values of the One-and Two-Phase Liquid (C V 1 , C V 2 ) and Vapor (C V 1 , C V 2 ) Isochoric Heat Capacities, Temperatures (T S ), and Densities (ρ S , ρ S ) of CO 2 + nDecane Mixtures Along the Saturation Curve [44], Valyshko et al [43], and Kamilov et al [42]). The dependence of the two-phase isochoric heat capacities of the CO 2 + n-decane mixtures on the specific volume along three selected isotherms and constant composition is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The technique used to determine T S and ρ S on the coexistence curve and of measuring the heat capacity C V on this curve is the method of quasi-static thermograms as described in detail in our previous publications [35][36][37][38][42][43][44]. The method of quasi-static thermograms makes it possible to obtain reliable phase transition temperatures, including a critical temperature, with an uncertainty of 0.02 K. The method of quasi-static thermograms (temperature vs. time, T-t plot) has been used to determine the location of the phase transition (L-V) boundaries for the CO 2 + n-decane mixtures near the critical points.…”

Section: Methods Of Quasi-static Thermogramsmentioning

confidence: 99%

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Isochoric Heat Capacity of CO2 + n-Decane Mixtures in the Critical Region

et al. 2006

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The isochoric heat capacity of two binary (CO 2 + n-decane) mixtures (0.095 and 0.178 mole fraction of n-decane) have been measured with a hightemperature, high-pressure, nearly constant volume adiabatic calorimeter. Measurements were made at nineteen near-critical liquid and vapor densities between 87 and 658 kg · m −3 for the composition of 0.095 mole fraction n-decane and at nine densities between 83 and 458 kg · m −3 for the composition of 0.178 mole fraction n-decane. The range of temperatures was 295 to 568 K. These temperature and density ranges include near-and supercritical regions. The measurements were performed in both one-and two-phase regions including the vapor + liquid coexistence curve. The uncertainty of the heat-capacity measurements is estimated to be 2% (coverage factor k = 2). The uncertainty in temperature is 15 mK, and that for density measurements is 0.06%. The liquid and vapor one-(C V 1 , C V 1 ) and two-phase (C V 2 , C V 2 ) isochoric heat capacities, temperatures (T S ), and densities (ρ S ) at saturation were measured by using the well-established method of quasi-static thermograms for each filling density. The critical temperatures (T C ), the critical densities (ρ C ), and the critical pressure (P C ) for the CO 2 + n-decane mixtures were extracted from the isochoric heat-capacity measurements on the coexistence curve. The observed isochoric heat capacity along the critical isochore of the CO 2 + n-decane mixture exhibits a renormalization of the critical behavior of C VX typical for mixtures. The values of the characteristic parameters (K 1 , K 2 ), temperatures (τ 1 , τ 2 ), and the characteristic density differences ( ρ 1 , ρ 2 ) were estimated for the CO 2 + n-decane mixture by using the critical-curve data and the theory of critical phenomena in 730 Polikhronidi, Batyrova, Abdulagatov, and Stepanov binary mixtures. The ranges of conditions were defined on the T-x plane for the critical isochore and the ρ-x plane for the critical isotherm, for which we observed renormalization of the critical behavior for the isochoric heat capacity.

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Section: Resultsmentioning

confidence: 99%

Section: Methods Of Quasi-static Thermogramsmentioning

confidence: 99%

Isochoric Heat Capacity of CO2 + n-Decane Mixtures in the Critical Region

et al. 2006

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“…The method of quasi-static thermograms (isochoric heat-capacity jumps and temperature versus time, T − τ , plot) was used in this work to accurately determine the location of the phase-boundary parameters (T S , ρ S , ρ S ) of pure methanol. Details of the method of quasi-static thermograms and its application to complex thermodynamic systems with different types of phase transitions (pure fluids and binary solutions with L-V, L-L, L-S, V-S, L-S-V, and L-L-S phasetransitions) are described in recent publications [36,40,41,[45][46][47].…”

Section: Measurements: Methods Of Quasi-static Thermogramsmentioning

confidence: 99%

Isochoric Heat-Capacity Measurements for Pure Methanol in the Near-Critical and Supercritical Regions

et al. 2007

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Isochoric heat-capacity measurements for pure methanol are presented as a function of temperature at fixed densities between 136 and 750 kg·m −3 . The measurements cover a range of temperatures from 300 to 556 K. The coverage includes the one-and two-phase regions, the coexistence curve, the near-critical, and the supercritical regions. A high-temperature, high-pressure, adiabatic, and nearly constant-volume calorimeter was used for the measurements. Uncertainties of the heat-capacity measurements are estimated to be 2-3% depending on the experimental density and temperature. Temperatures at saturation, T S (ρ), for each measured density (isochore) were measured using a quasi-static thermogram technique. The uncertainty of the phase-transition temperature measurements is 0.02 K. The critical temperature and the critical density for pure methanol were extracted from the saturated data (T S , ρ S ) near the critical point. For one near-critical isochore (398.92 kg·m −3 ), the measurements were performed in both cooling and heating regimes to estimate the effect of thermal decomposition (chemical reaction) on the heat capacity and phase-transition properties of methanol. The measured values of C V and saturated densities (T S , ρ S ) for methanol were compared with values calculated from various multiparametric equations of state (EOS) (IUPAC, Bender-type, polynomial-type, and nonanalytical-type), scaling-type (crossover) EOS, and various correlations. The measured C V data have been analyzed and interpreted in terms of extended scaling equations for 163 0195-928X/07/0200-0163/0 © 2007 Springer Science+Business Media, LLC 164 Polikhronidi et al.the selected thermodynamic paths (critical isochore and coexistence curve) to accurately calculate the values of the asymptotical critical amplitudes (A ± 0 and B 0 ).

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“…Data on salt deposition from the vapor are part of a recent NIST correlation [10] Two papers on the heat capacity work are in press [11,12].…”

Section: Extended Abstractmentioning

confidence: 99%

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

Shaw¹,

Boukis²

2000

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Approved for public release; distribution unlimited. AbstractThe U.S. Army is developing supercritical water oxidation for destruction of military toxic materials. The properties of high-temperature aqueous solutions are not, in most cases, well known. Understanding the phase behavior of these solutions will facilitate design and efficient operation of high-temperature water reactors. A U.S. Army workshop held at the Forschungzentrum Karlsruhe in July 1999 assembled experts on phase behavior to develop guidelines that, in the absence of more complete knowledge of solution properties, will aid reactor designers and operators. The experts presented papers on model systems, properties of high-temperature aqueous solutions, and chemistry in high-temperature water. Following these presentations, the experts developed some of the desired rules of thumb and made recommendations for research to develop these guidelines further. This workshop report includes the presentation papers, guidelines, and recommendations for research. Distribution 67Report Documentation Page 71 Participants in the workshop 2Hong, Model Systems P-T-x diagram for Type la systems and Type lb systems 122. T-x diagram for NaCI-H 2 0 at 250 bar 13 3. P-T projection of solidus for NaCI-H 2 0 14 4. P-T-x diagrams for Type 2a systems, and Type 2b systems 14 5. T-x projection of phase diagram for ternary systems of Type 1: subtype A, subtype B, and subtype C 16 6. P-T projection of eutonic curve for NaCl-Na 2 S04-H 2 0 system ... 177. Temperature progression of phase diagrams at 225 bar for NaCINa 2 S04-H 2 0 system 17 Supercritical water (SCW) oxidation (SCWO) provides a powerful means to transform toxic organic materials into simple, relatively inert oxides. Water at high temperatures and pressures is an active medium, however, and its properties and those of its solutions are only partially understood. Indeed, two principal challenges to broad use of this technology are (1) the materials requirements for the reactor and the heatup and cooldown sections, and (2) the incomplete understanding of and ability to predict the phase behavior of SCW solutions.Phase separations have the potential to impair the operation of an SCWO reactor (1) by dramatically changing transport properties (especially in the presence of dynamically separating liquid and solid phases), (2) by generating solid particles that may plug reactor orifices and deposit on reactor surfaces, and (3) by producing a highly corrosive electrochemical environment. Objectives for This WorkshopWe sought to develop (or recommend methodologies to develop) guidelines/rules of thumb for phase separations in organic/salt/gas/aqueous solutions in SCWO processing for defined sets of feed compositions. Useful speculations about these phase separations are in the areas not only of equilibrium thermodynamics (e.g., solubility), but also of the kinetics of phase separation and growth (e.g., the problem of heterogeneous nucleation). The phase separation guidelines are intended to indicate regions of safe (pr...

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Vapor−Liquid−Solid Phase Transitions in Aqueous Sodium Sulfate and Sodium Carbonate from Heat Capacity Measurements near the First Critical End Point. 1. Sodium Sulfate

Cited by 10 publications

References 8 publications

Isochoric Heat Capacity of CO2 + n-Decane Mixtures in the Critical Region

Isochoric Heat Capacity of CO2 + n-Decane Mixtures in the Critical Region

Isochoric Heat-Capacity Measurements for Pure Methanol in the Near-Critical and Supercritical Regions

Guidelines for Phase Separations in High-Temperature and Supercritical Water Solutions: A Report on a Workshop Organized by the U.S. Army Research Office and the Forschungzentrum Karlsruhe, 7-9 July 1999

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