Solubility of sodium chloride and sulfate in sub- and supercritical water vapor from 450–550°C and 100–250 bar

Armellini, Fred J.; Tester, Jefferson W.

doi:10.1016/0378-3812(93)85120-b

Cited by 150 publications

(122 citation statements)

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“…Eventually, after residence times of about 1 minute, full mineralization occurs to C0 2 , H 2 0, molecular N 2 , and inorganic acids associated with the heteroatoms (Cl, S, P, F). A key area many research groups have focused on is characterizing the rates and mechanisms of hydrolysis and oxidation reactions of model compounds under well-defined reaction conditions of T, P, p, x ir and residence time (Tester et al, 1993(Tester et al, ,1998Savage et al, 1995Savage et al, ,1999.…”

Section: Chemical and Phase Reactions In Supercritical Watermentioning

confidence: 99%

“…In the second area, the research focus has been on experimental characterization of phase boundaries and compositions in binary (single salt-water) and ternary (two salt-water) systems (e.g., Armellini and Tester, 1993;DiPippo et al, 1999) and on modeling of salt-water systems in general (Cui and Harris, 1995a,b;Reagan et al, 1999;Tester et al, 1998).…”

Section: Chemical and Phase Reactions In Supercritical Watermentioning

confidence: 99%

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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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Section: Chemical and Phase Reactions In Supercritical Watermentioning

confidence: 99%

Section: Chemical and Phase Reactions In Supercritical Watermentioning

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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“…The variations of the HTC plotted against the bulk temperature showing the effects of mass flux and pressure are shown in Figure 11 The increased HTC and maximum value near the pseudo-critical temperatures has been observed in studies conducted by several authors 9,10,12,14,[23][24][25][26] on heat transfer to SCW flows at high mass fluxes. Yamagata et al 9 attributed this behavior to the large changes in the physical properties of the fluid produced by small changes in temperature "across the section" of the tube.…”

Section: Effects Of Mass Flux and Pressure On Heat Transfermentioning

confidence: 73%

“…Olander and Liander, 20 Parisod and Plattner, 21 Bischoff et al, 22 Sourirajan and Kennedy, 23 found in literature might lead to possible errors in the solubility of NaCl in the pressure and temperature range of interest to the process, therefore, it is decided to measure the solubility of NaCl in supercritical water at these process conditions in the vapor and liquid phase in one experiment. The apparatus was also used for the proof of concept of the separation method.…”

Section: Phase Equilibrium Measurementsmentioning

confidence: 99%

“…When temperature differences are introduced through boundaries maintained at different temperatures, the resulting density differences will induce motion; hot fluid tends to rise, cold fluid tends to fall. 23 When both forced and natural convection are present in a system, this is called mixed convection. 15 There are two types of mixed convection: (i) aiding flow, when natural convection acts in the same direction as forced convection, and (ii) opposing flow, where natural convection acts in the opposite direction to forced convection.…”

Section: Natural Convectionmentioning

confidence: 99%

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Supercritical water desalination (SCWD): process development, design and pilot plant validation

Odu¹

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The research described in this thesis was financially supported by Wetsus, European Centre of Excellence for Sustainable Water Technology. The main objective of the work reported in this dissertation is the development, design and construction of a pilot plant scale SCWD process that produces drinking quality water and solid salt. SUPERCRITICAL WATER DESALINATION (SCWD)PROCESSIn order to design a SCWD process, it is essential to know the phases present under supercritical water conditions and understand how the process conditions °C at 250 bar, and 475 °C at 300 bar respectively. In addition, the phase equilibrium ii solubility of NaCl−H 2 O was studied under isobaric conditions in a lab-scale experimental setup. The results of the visualization experiments and phase equilibrium measurements show that the SCWD process could be operated in two stages: (i) a V−L separator to remove the supercritical product water from the liquid phase at 250/300 bar, and (ii) a V−S separator to obtain the solid salt by flashing the liquid phase (a highly concentrated salt solution, 50 wt.% at 300 bar, 460 °C) to atmospheric pressure. The two-stage operation is necessary to avoid salts precipitation in the early stage of the process which could lead to equipment blockage and downtime.Simulation of the SCWD process using water was carried out in UniSim Design at 250 and 300 bar pressure. Simulation results show that operating the SCWD process at 300 bar offers better heat integration potential as well as a 22% reduction in thermal energy consumption compared to operating at 250 bar. A conceptual design and a lab-scale (12 g/hr) demonstration of the proof-of-concept of the SCWD process using 3.5 wt.% NaCl-H 2 O solution are presented in Chapter 2.The SCWD process is energy intensive, therefore heat integration is essential to regain as much energy as possible from the process in order to make the process a commercial success. Understanding the heat transfer mechanism as well as knowing the heat transfer coefficient of sub-to supercritical water (SCW) flow is essential to design a heat exchanger required for the heat integration. In Chapter 3, 2D numerical simulations were carried out in COMSOL Multiphysics to provide essential insights into the heat transport mechanism of SCW flow at low mass fluxes. The results show that the heat transport mechanism is primarily by buoyancy-induced circulation resulting from gravitational force acting on density gradients (a direct consequence of temperature gradients) across the section of the tube. From the numerical results, a 1D Nusselt correlation for engineering design was developed and validated with experimental temperature measurements.In Chapter 4, two experimental measurement methods -local and spatially averaged -to measure the heat transfer coefficient (HTC) of SCW are presented.Only the local measurement method has enough resolution and accuracy to detect the maximum in HTC near the pseudo-critical temperature. No noticeable effect of iii an increase in mass flux is observed due to th...

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Molecular‐Based Modeling of Water and Aqueous Solutions at Supercritical Conditions

Chialvo

Cummings

1999

Advances in Chemical Physics

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Solubility of sodium chloride and sulfate in sub- and supercritical water vapor from 450–550°C and 100–250 bar

Cited by 150 publications

References 13 publications

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

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

Supercritical water desalination (SCWD): process development, design and pilot plant validation

Molecular‐Based Modeling of Water and Aqueous Solutions at Supercritical Conditions

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