Modelling of cross-flow membrane contactors : Physical mass transfer processes

NARCIS (Netherlands)

Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

2005-01-01

Traditionally, hollow fiber membrane contactors used for gas-liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called 'parallel flow'

Physical and mathematical modeling of diesel fuel liquid and vapor movement in porous media

International Nuclear Information System (INIS)

Johnson, T.E.; Kreamer, D.K.

1994-01-01

Two-dimensional physical modeling of diesel fuel leaks was conducted in sand tanks to determine liquid and vapor migration characteristics. Mathematical modeling provided estimation of vapor concentrations at discrete times and distances from the vapor source and was compared to the physical experiment. The mathematical gaseous diffusion model was analogous to the Theis equation for ground-water flow, accounted for sorptive effects of the media, and was calibrated using measured concentrations from the sand tank. Mathematically different positions of the vapor source were tested to better relate observed liquid flow rates and media configuration to gaseous concentrations. The calculated diffusion parameters were then used to estimate theoretical, three-dimensional vapor transport from a hypothetical liquid leak of 2.0 1/hr for 30 days. The associated three-dimensional vapor plume, which would be reasonably detectable by commercially available vadose zone monitors, was estimated to have a diameter of 8 m with a vapor concentration of 50 ppm at the outside edge of the vapor plume. A careful application of the method and values can be used to give a first approximation to the number of vapor monitors required at a field site as well as the optimal locations for the monitors

Surface modification of poly(vinylidene fluoride) hollow fibre membranes for biogas purification in a gas-liquid membrane contactor system.

Science.gov (United States)

Jin, Pengrui; Huang, Chuan; Li, Jiaxiang; Shen, Yadong; Wang, Liao

2017-11-01

The wetting of hollow fibre membranes decreases the performance of the liquid-gas membrane contactor for CO 2 capture in biogas upgrading. To solve this problem, in this work, a poly(vinylidene fluoride) (PVDF) hollow fibre membrane for a liquid-gas membrane contactor was coated with a superhydrophobic layer composed of a combination of hydrophobic SiO 2 nanoparticles and polydimethylsiloxane (PDMS) by the method of spray deposition. A rough layer of SiO 2 deposited on the PVDF membrane resulted in an enhanced surface hydrophobicity. The surface structure of the pristine PVDF significantly affected the homogeneity of the generated SiO 2 layer. A uniform surface coating on the PVDF upper layer resulted from the presence of micrometre and nanometre-sized roughness on the surface of the PVDF membrane, which was achieved with a SiO 2 concentration of 4.44 mg ml -1 (0.2 g/45 ml) in the coating solution. As a result, the water contact angle of the modified surface was recorded as 155 ± 3°, which is higher than that of the pristine surface. The high contact angle is advantageous for reducing the wetting of the membrane. Additional mass transfer resistance was introduced by the superhydrophobic layer. In addition, continuous CO 2 absorption tests were carried out in original and modified PVDF hollow fibre membrane contactors, using monoethanolamine (MEA) solution as the absorbent. A long-term stability test revealed that the modified PVDF hollow fibre membrane contactor was able to outperform the original membrane contactor and demonstrated outstanding long-term stability, suggesting that spray deposition is a promising approach to obtain superhydrophobic PVDF membranes for liquid-gas membrane absorption.

CALmsu contactor for solvent extraction with integrated flowrate meters

Energy Technology Data Exchange (ETDEWEB)

Siddiqui, I A; Shah, B V; Theyyunni, T K [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Mixer-settlers are widely used as contactors in solvent extraction processes. In the nuclear industry, solvent extraction techniques are used for the separation and purification of a range of materials. A major difficulty is faced in the nuclear industry due to the constraints on the design of the equipment and its operation by the presence of radioactive materials in process solutions. The development of CALmsu contactor was necessitated by the requirements of the operating environment in radiochemical plants. This contactor is a mixer-settler designed to use a CALMIX (combined air lifting and mixing device) static mixer. The CALMIX comprises two air lifts which raise the liquid phases to a highly turbulent mixing zone situated above the lifts. Its principle and construction are simple, and it is compact in size. It is a passive device and needs no maintenance. It has proved to be efficient during extensive testing. The simple and efficient CALmsu contactor internals are specially engineered for use of CALMIX mixer. It has been extensively tested in pilot plant for extraction and stripping of uranium, recovery of uranium from thorium by THOREX process and for treatment of degraded solvents. A model for the design of CALmsu contactors has been evolved and based on this model a software for engineering design of CALMIX and CALmsu contactors of throughput between 50 and 3000 lph has been developed. (author). 8 refs., 1 fig.

Extraction of zirconium from simulated acidic nitrate waste using liquid membrane in hollow fiber contactor

International Nuclear Information System (INIS)

Pandey, G.; Chinchale, R.; Renjith, A.U.; Dixit, S.; Mukhopadhyay, S.; Shenoy, K.T.; Ghosh, S.K.

2015-01-01

The acidic waste raffinate stream of zirconium (Zr) purification plant contains about 2 gpl of Zr in about 2M free nitric acid. TBP, which is the most commonly used solvent in the nuclear industry, is not suitable for the extraction of Zr from this lean solution as its distribution coefficient is less than one. In house synthesized Mixed Alkyl Phosphine Oxide (MAPO) is a potential extractant for Zr from this lean stream. Intensification of this process for recovery of Zr has been attempted through use of efficient contactor, namely, hollow fiber module and efficient process, namely, simultaneous extraction and stripping across liquid membrane containing MAPO. Based on batch equilibrium studies selection of suitable concentration of extractant, composition of diluent, selection and concentration of strippant for the proposed liquid membrane system was made. The selected organic and strippant concentration was used to study suitability of application of Dispersion Liquid Membrane (DLM) in hollow fiber contactor for recovery Zr from solution simulated to Zr plant raffinate. Challenges related to stable operation of the liquid membrane system like stability of the organic phase in the micropores of lumen and stability of the dispersion during the pertraction were addressed through pressure balance across the lumen and choice of adequate dispersion condition respectively. (author)

Thermogravimetric measurements of liquid vapor pressure

International Nuclear Information System (INIS)

Rong Yunhong; Gregson, Christopher M.; Parker, Alan

2012-01-01

Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

The liquid to vapor phase transition in excited nuclei

Energy Technology Data Exchange (ETDEWEB)

Elliott, J.B.; Moretto, L.G.; Phair, L.; Wozniak, G.J.; Beaulieu, L.; Breuer, H.; Korteling, R.G.; Kwiatkowski, K.; Lefort, T.; Pienkowski, L.; Ruangma, A.; Viola, V.E.; Yennello, S.J.

2001-05-08

For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid-vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197 Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.

Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems

DEFF Research Database (Denmark)

Thomsen, Kaj; Rasmussen, Peter

1999-01-01

A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon ...

Recent advances in centrifugal contactors design

International Nuclear Information System (INIS)

Leonard, R.A.

1987-10-01

Advances in thedesign of the Argonne centrifugal contactor for solvent extaction are being realized as these contactors are built, tested, and used to implement the TRUEX process for the cleanup of nuclear waste liquids. These advances include (1) using off-the-shelf, face-mounted motors, (2) modifying the contractor so that relatively volatile solvents can be used, (3) adding a high-level liquid detector that can be used to alert the plant operator of process upsets, (4) providing secondary feed ports, (5) optimizing support frame design, (6) maintaining a linear design with external interstage lines so the stages can be allocated as needed for extraction, scrub, strip, and solvent cleanup operations, and (7) developing features that facilitate contractor operation in remote facilities. 11 refs., 8 figs

Plasma contactor development for Space Station

Science.gov (United States)

Patterson, Michael J.; Hamley, John A.; Sarmiento, Charles J.; Manzella, David H.; Sarver-Verhey, Timothy; Soulas, George C.; Nelson, Amy

1993-01-01

Plasma contactors have been baselined for the Space Station (SS) to control the electrical potentials of surfaces to eliminate/mitigate damaging interactions with the space environment. The system represents a dual-use technology which is a direct outgrowth of the NASA electric propulsion program and, in particular, the technology development effort on ion thrustor systems. The plasma contactor subsystems include the plasma contactor unit, a power electronics unit, and an expellant management unit. Under this pre-flight development program these will all be brought to breadboard or engineering model status. Development efforts for the plasma contactor include optimizing the design and configuration of the contactor, validating its required lifetime, and characterizing the contactor plume and electromagnetic interference. The plasma contactor unit design selected for the SS is an enclosed keeper, xenon hollow cathode plasma source. This paper discusses the test results and development status of the plasma contactor unit subsystem for the SS.

Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications

Science.gov (United States)

Thompson, W. R.; Zollweg, John A.; Gabis, David H.

1992-01-01

A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.

Annular centrifugal contactors for TRPO process test

International Nuclear Information System (INIS)

Duan, W.H.; Wang, J.C.; Chen, J.; Zhou, X.Z.; Zhou, J.Z.; Song, C.L.

2005-01-01

The TRPO process has been developed in China for removing TRU elements from high-level liquid waste (HLLW) since 1980s. Centrifugal contactors have several advantages such as low hold-up volume, short residence time, low solvent degradation, small space requirements and short start-up time. Therefore, they are favored for both the reprocessing of spent fuel and the treatment of HLLW. In order to meet study on the TRPO test, a series of annular centrifugal contactors have been developed in Institute of Nuclear and -New Energy Technology, Tsinghua University, China (INET). In particular, the 10-mm annular centrifugal contactor for the laboratory-scale test has been applied successfully in the cold and hot tests of the TRPO process. The 70-mm annular centrifugal contactor for the industry-scale test has two new design characteristics, namely a modular design and an overflow structure. The modular design makes the contactor to be disassembled and assembled fast by simply moving the modules up and down. With the overflow structure, even though one stage or non-adjacent stages of the multi-stage cascade in operation are ceased to work, the cascade can continue to operate. Both the hydraulic performance and the mass-transfer efficiency of these contactors are excellent, and the extraction stage efficiency is greater than 95% at suitable operating conditions.

A technical review of liquid/liquid and solid/liquid separation equipment in the field of nuclear-fuel reprocessing

International Nuclear Information System (INIS)

Vassallo, G.

1981-01-01

Liquid/liquid extraction is generally accepted as the preferred method in nuclear-fuel reprocessing. However, although many types of liquid/liquid contactors are available, only a few meet the stringent specifications set by the nuclear industry. This report discusses the criteria for contactor selection and then reviews the most important types, namely packed columns, pulsed columns, mixer-setters and centrifugal contactors. Finally, a short section concerned with solid/liquid separations is included because of the possible deleterious effects caused by solids in liquid/liquid contactors

Liquid-liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials

Model for the dynamic study of AC contactors

Energy Technology Data Exchange (ETDEWEB)

Corcoles, F.; Pedra, J.; Garrido, J.P.; Baza, R. [Dep. d' Eng. Electrica ETSEIB. UPC, Barcelona (Spain)

2000-08-01

This paper proposes a model for the dynamic analysis of AC contactors. The calculation algorithm and implementation are discussed. The proposed model can be used to study the influence of the design parameters and the supply in their dynamic behaviour. The high calculation speed of the implemented algorithm allows extensive ranges of parameter variations to be analysed. (orig.)

Vapor trap for liquid metal

Energy Technology Data Exchange (ETDEWEB)

Watanabe, T

1968-05-22

In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

Science.gov (United States)

Stewart, Mark E. M.

2017-01-01

This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

Liquid--liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This well-known phenomenon is called a ''vapor explosion.'' One method of producing intimate, liquid--liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. In this experiment cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture). The main conclusion from the experimental study is that hydrodynamic effects may be very significant in any shock tube analyses, especially when multiple interactions are observed. A theoretical study was performed to check the possibility of vapor film squeezing (between a drop in film boiling and a surface) as a controlling mechanism for making liquid--liquid contact. Using experimental data, the film thickness was calculated and it was found to be too thick for any conceivable film rupture mechanism. It was suggested that the coalescence is a two-stage process, in which the controlling stage depends mainly on temperature and surface properties and can be described as the ability of cold liquid to spread on a hot surface

Numerical simulation of superheated vapor bubble rising in stagnant liquid

Science.gov (United States)

Samkhaniani, N.; Ansari, M. R.

2017-09-01

In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

Gas-liquid mass transfer in a cross-flow hollow fiber module : Analytical model and experimental validation

NARCIS (Netherlands)

Dindore, V. Y.; Versteeg, G. F.

2005-01-01

The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations

Extended UNIQUAC Model for Correlation and Prediction of Vapor-Liquid-Liquid-Solid Equilibria in Aqueous Salt Systems Containing Non-Electrolytes. Part B. Alcohol (Ethanol, Propanols, Butanols) - Water-salt systems

DEFF Research Database (Denmark)

Thomsen, Kaj; Iliuta, Maria Cornelia; Rasmussen, Peter

2004-01-01

The Extended UNIQUAC model for electrolyte solutions is an excess Gibbs energy function consisting of a Debye-Huckel term and a term corresponding to the UNIQUAC equation. For vapor-liquid equilibrium calculations, the fugacities of gas-phase components are calculated with the Soave-Redlich-Kwong......The Extended UNIQUAC model for electrolyte solutions is an excess Gibbs energy function consisting of a Debye-Huckel term and a term corresponding to the UNIQUAC equation. For vapor-liquid equilibrium calculations, the fugacities of gas-phase components are calculated with the Soave...... solid-liquid-vapor equilibrium and thermal property data for strongly non-ideal systems. In this work, the model is extended to aqueous salt systems containing higher alcohols. The calculations are based on an extensive database consisting of salt solubility data, vapor liquid equilibrium data...

Non-equilibrium phenomena near vapor-liquid interfaces

CERN Document Server

Kryukov, Alexei; Puzina, Yulia

2013-01-01

This book presents information on the development of a non-equilibrium approach to the study of heat and mass transfer problems using vapor-liquid interfaces, and demonstrates its application to a broad range of problems. In the process, the following peculiarities become apparent: 1. At vapor condensation on the interface from gas-vapor mixture, non-condensable components can lock up the interface surface and condensation stops completely. 2. At the evolution of vapor film on the heater in superfluid helium (He-II), the boiling mass flux density from the vapor-liquid interface is effectively zero at the macroscopic scale. 3. In problems concerning the motion of He-II bridges inside capillaries filled by vapor, in the presence of axial heat flux the He-II bridge cannot move from the heater as would a traditional liquid, but in the opposite direction instead. Thus the heater attracts the superfluid helium bridge. 4. The shape of liquid-vapor interface at film boiling on the axis-symmetric heaters immersed in l...

Uranium and zirconium mass transfer testing of 5.5-cm-diam centrifugal contactors

International Nuclear Information System (INIS)

DeMuth, S.F.; Randolph, J.D.

1988-01-01

As part of the Consolidated Fuel Reprocessing Program of the Oak Ridge National Laboratory, compact centrifugal contacts were designed and prototypes build for the Breeder Reprocessing Engineering Test (BRET) facility with a throughput capacity of 0.1 t/d of heavy metals. While the construction of BRET has been put on hold indefinitely, development of the 5.5-cm-diam centrifugal contactors has advanced due to the contactor's broad applicability in other areas of fuel reprocessing and other liquid-liquid extraction. Due to the short residence time of the process fluids in a centrifugal contactor, it was necessary to measure the mass transfer efficiency for a typical process flowsheet. This was done with depleted uranium and 91 Zr. The results of mass transfer tests with uranium and zirconium are reported in this paper

Liquid-liquid contact in vapor explosion. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture).

Numerical Simulation of Vapor Bubble Growth and Heat Transfer in a Thin Liquid Film

International Nuclear Information System (INIS)

Yu-Jia, Tao; Xiu-Lan, Huai; Zhi-Gang, Li

2009-01-01

A mathematical model is developed to investigate the dynamics of vapor bubble growth in a thin liquid film, movement of the interface between two fluids and the surface heat transfer characteristics. The model takes into account the effects of phase change between the vapor and liquid, gravity, surface tension and viscosity. The details of the multiphase now and heat transfer are discussed for two cases: (1) when a water micro-droplet impacts a thin liquid film with a vapor bubble growing and (2) when the vapor bubble grows and merges with the vapor layer above the liquid film without the droplet impacting. The development trend of the interface between the vapor and liquid is coincident qualitatively with the available literature, mostly at the first stage. We also provide an important method to better understand the mechanism of nucleate spray cooling. (fundamental areas of phenomenology (including applications))

Numerical modeling of a vaporizing multicomponent droplet

Science.gov (United States)

Megaridis, C. M.; Sirignano, W. A.

The fundamental processes governing the energy, mass, and momentum exchange between the liquid and gas phases of vaporizing, multicomponent liquid droplets have been investigated. The axisymmetric configuration under consideration consists of an isolated multicomponent droplet vaporizing in a convective environment. The model considers different volatilities of the liquid components, variable liquid properties due to variation of the species concentrations, and non-Fickian multicomponent gaseous diffusion. The bicomponent droplet model was employed to examine the commonly used assumptions of unity Lewis number in the liquid phase and Fickian gaseous diffusion. It is found that the droplet drag coefficients, the vaporization rates, and the related transfer numbers are not influenced by the above assumptions in a significant way.

Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

Directory of Open Access Journals (Sweden)

A. C. D. Freitas

2013-03-01

Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.

Numerical modelling of multiphase liquid-vapor-gas flows with interfaces and cavitation

Science.gov (United States)

Pelanti, Marica

2017-11-01

We are interested in the simulation of multiphase flows where the dynamical appearance of vapor cavities and evaporation fronts in a liquid is coupled to the dynamics of a third non-condensable gaseous phase. We describe these flows by a single-velocity three-phase compressible flow model composed of the phasic mass and total energy equations, the volume fraction equations, and the mixture momentum equation. The model includes stiff mechanical and thermal relaxation source terms for all the phases, and chemical relaxation terms to describe mass transfer between the liquid and vapor phases of the species that may undergo transition. The flow equations are solved by a mixture-energy-consistent finite volume wave propagation scheme, combined with simple and robust procedures for the treatment of the stiff relaxation terms. An analytical study of the characteristic wave speeds of the hierarchy of relaxed models associated to the parent model system is also presented. We show several numerical experiments, including two-dimensional simulations of underwater explosive phenomena where highly pressurized gases trigger cavitation processes close to a rigid surface or to a free surface. This work was supported by the French Government Grant DGA N. 2012.60.0011.00.470.75.01, and partially by the Norwegian Grant RCN N. 234126/E30.

Investigation of H2S and CO2 Removal from Gas Streams Using Hollow Fiber Membrane Gas–liquid Contactors

Directory of Open Access Journals (Sweden)

S. M. Mirfendereski

2017-07-01

Full Text Available Chemical absorption of H2S and CO2 from CH4 was carried out in a polypropylene porous asymmetric hollow fiber membrane contactor (HFMC. A 0.5 mol L–1 aqueous solution of methyldiethanolamine (MDEA was used as chemical absorbent solution. Effects of gas flow rate, liquid flow rate, H2S concentration and CO2 concentration on the H2S outlet concentrations and CO2 removal percentage were investigated. The results showed that the removal of H2S with aqueous solution of MDEA was very high and indicated almost total removal of H2S. Experimental results also indicated that the membrane contactor was very efficient in the removal of trace H2S at high gas/ liquid flow ratio. The removal of H2S was almost complete with a recovery of more than 96 %. Using feed gas mixtures containing 5000 ppm H2S with CO2 concentrations in the range of 4–12 vol.%, the outlet H2S concentration of less than 1.0 ppm was attained with less than 4.0 vol.% of CO2 permeated and absorbed.

Modeling Cryptosporidium spp. Oocyst Inactivation in Bubble-Diffuser Ozone Contactors

Science.gov (United States)

1998-07-01

requirements for Giardia lamblia (G. lamblia) and viruses under the Surface Water Treatment Rule (SWTR). Minimum CT requirements include relatively...parvum and C. muris ) oocysts in ozone bubble-diffuser contactors. The model is calibrated with semi-batch kinetic data, verified with pilot-scale

Experimental study of vapor explosion of molten salt and low boiling point liquid

International Nuclear Information System (INIS)

Iida, Yoshihiro; Takashima, Takeo

1987-01-01

Fundamental study of vapor explosion using small drops of high temperature liquid and low boiling point liquid and a series of small-scale vapor explosion tests are carried out. A single or plural drops of molten LiNO 3 are dropped into ethyl alcohol and the temperature range of two liquids wherein the fragmentation occurs is examined. The propagation phenomenon of vapor explosion between two drops is photographed and the pressure trace is proved to be well consistent with the behavior of the vapor bubble regions. A small amount of molten Flinak and tin which are enclosed in a test tube is dropped into tapped water. The temperature effect of two liquids onto the occurrence of vapor explosion is investigated. Some considerations are made with respect to the upper and lower temperature limits of vapor explosion to occur. A qualitative modeling of vapor explosion mechanism is proposed and discussed. (author)

Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO2 + alkanol) binary systems

International Nuclear Information System (INIS)

Bejarano, Arturo; Gutierrez, Jorge E.; Araus, Karina A.; Fuente, Juan C. de la

2011-01-01

Research highlights: → (Vapor + liquid) equilibria of three (CO 2 + C 5 alcohol) binary systems were measured. → Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. → No liquid immiscibility was observed at the temperatures and pressures studied. → Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. → Correlation results showed relative deviations ≤8 % (liquid) and ≤2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO 2 + 3-methyl-2-butanol), (CO 2 + 2-pentanol), and (CO 2 + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO 2 + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle.

Science.gov (United States)

Đorđević, Jelena; Vladisavljević, Goran T; Trtić-Petrović, Tatjana

2017-01-01

A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P ≥ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

Shock wave of vapor-liquid two-phase flow

Institute of Scientific and Technical Information of China (English)

Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

2008-01-01

The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

Membrane contactors in the beverage industry for controlling the water gas composition.

Science.gov (United States)

Criscuoli, Alessandra; Drioli, Enrico; Moretti, Ugo

2003-03-01

In the work described here, membrane contactors are used for coupling the removal of species (oxygen and hydrogen sulfide) present in the water with the water carbonation process. We include both experiments and a theoretical study devoted to the analysis of the transport phenomena that occur in the membrane contactor. The main resistance to mass transport was located at the liquid side. Correlations between Sherwood and Reynolds numbers on the shell side that are suitable for the membrane contactor used to carry out our experiments have been determined. In particular, for Re > 1.6, the expression proposed by Yang and Cussler in 1986: Sh = 0.90 Re(0.40) Sc(0.33) describes the behavior of the system; whereas, for Re between 0.03 and 0.3, a new expression is proposed: Sh = 0.435 Re(1.2)Sc(0.33). A comparison with traditional equipment is also furnished. Membrane contactors offer reduced size, CO(2) consumption, and capital costs.

Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A

NARCIS (Netherlands)

Matheis, Jan; Hickel, S.

2018-01-01

We present and evaluate a two-phase model for Eulerian large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model is based on cubic equations of state and vapor-liquid equilibrium calculations and can represent the coexistence of supercritical states and

Motion of liquid plugs between vapor bubbles in capillary tubes: a comparison between fluids

Science.gov (United States)

Bertossi, Rémi; Ayel, Vincent; Mehta, Balkrishna; Romestant, Cyril; Bertin, Yves; Khandekar, Sameer

2017-11-01

Pulsating heat pipes (PHP) are now well-known devices in which liquid/vapor slug flow oscillates in a capillary tube wound between hot and cold sources. In this context, this paper focuses on the motion of the liquid plug, trapped between vapor bubbles, moving in capillary tubes, to try to better understand the thermo-physical phenomena involved in such devices. This study is divided into three parts. In the first part, an experimental study presents the evolution of the vapor pressure during the evaporation process of a liquid thin film deposited from a liquid plug flowing in a heated capillary tube: it is found that the behavior of the generated and removed vapor can be very different, according to the thermophysical properties of the fluids. In the second part, a transient model allows to compare, in terms of pressure and duration, the motion of a constant-length liquid plug trapped between two bubbles subjected to a constant difference of vapor pressure: the results highlight that the performances of the four fluids are also very different. Finally, a third model that can be considered as an improvement of the second one, is also presented: here, the liquid slug is surrounded by two vapor bubbles, one subjected to evaporation, the pressure in both bubbles is now a result of the calculation. This model still allows comparing the behaviors of the fluid. Even if our models are quite far from a complete model of a real PHP, results do indicate towards the applicability of different fluids as suitable working fluids for PHPs, particularly in terms of the flow instabilities which they generate.

Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO{sub 2} + alkanol) binary systems

Energy Technology Data Exchange (ETDEWEB)

Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)

2011-05-15

Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

Long term pilot plant experience on aromatics extraction with ionic liquids

NARCIS (Netherlands)

Meindersma, W.G.W.; Onink, F.S.A.F.; Hansmeier, A.R.; Haan, de A.B.

2012-01-01

Since 2004, we have been conducting pilot plant trials with various contactors and different ionic liquids for petrochemical model feeds as well as real refinery feeds. Our pilot plant contains a Rotating Disc Contactor with a height of 6 m and a diameter of 60 mm. Up to 100 kg of ionic liquid and

Extended residence time centrifugal contactor design modification and centrifugal contactor vane plate valving apparatus for extending mixing zone residence time

Science.gov (United States)

Wardle, Kent E.

2017-06-06

The present invention provides an annular centrifugal contactor, having a housing adapted to receive a plurality of flowing liquids; a rotor on the interior of the housing; an annular mixing zone, wherein the annular mixing zone has a plurality of fluid retention reservoirs with ingress apertures near the bottom of the annular mixing zone and egress apertures located above the ingress apertures of the annular mixing zone; and an adjustable vane plate stem, wherein the stem can be raised to restrict the flow of a liquid into the rotor or lowered to increase the flow of the liquid into the rotor.

Modelling and numerical simulation of liquid-vapor phase transitions

International Nuclear Information System (INIS)

Caro, F.

2004-11-01

This work deals with the modelling and numerical simulation of liquid-vapor phase transition phenomena. The study is divided into two part: first we investigate phase transition phenomena with a Van Der Waals equation of state (non monotonic equation of state), then we adopt an alternative approach with two equations of state. In the first part, we study the classical viscous criteria for selecting weak solutions of the system used when the equation of state is non monotonic. Those criteria do not select physical solutions and therefore we focus a more recent criterion: the visco-capillary criterion. We use this criterion to exactly solve the Riemann problem (which imposes solving an algebraic scalar non linear equation). Unfortunately, this step is quite costly in term of CPU which prevent from using this method as a ground for building Godunov solvers. That is why we propose an alternative approach two equations of state. Using the least action principle, we propose a phase changing two-phase flow model which is based on the second thermodynamic principle. We shall then describe two equilibrium submodels issued from the relaxations processes when instantaneous equilibrium is assumed. Despite the weak hyperbolicity of the last sub-model, we propose stable numerical schemes based on a two-step strategy involving a convective step followed by a relaxation step. We show the ability of the system to simulate vapor bubbles nucleation. (author)

CFD simulation of copper(II) extraction with TFA in non-dispersive hollow fiber membrane contactors.

Science.gov (United States)

Muhammad, Amir; Younas, Mohammad; Rezakazemi, Mashallah

2018-04-01

This study presents computational fluid dynamics (CFD) simulation of dispersion-free liquid-liquid extraction of copper(II) with trifluoroacetylacetone (TFA) in hollow fiber membrane contactor (HFMC). Mass and momentum balance Navier-Stokes equations were coupled to address the transport of copper(II) solute across membrane contactor. Model equations were simulated using COMSOL Multiphysics™. The simulation was run to study the detailed concentration distribution of copper(II) and to investigate the effects of various parameters like membrane characteristics, partition coefficient, and flow configuration on extraction efficiency. Once-through extraction was found to be increased from 10 to 100% when partition coefficient was raised from 1 to 10. Similarly, the extraction efficiency was almost doubled when porosity to tortuosity ratio of membrane was increased from 0.05 to 0.81. Furthermore, the study revealed that CFD can be used as an effective optimization tool for the development of economical membrane-based dispersion-free extraction processes.

Thermodynamic Modeling and Mechanical Design of a Liquid Nitrogen Vaporization and Pressure Building Device

Science.gov (United States)

Leege, Brian J.

The design of a liquid nitrogen vaporization and pressure building device that has zero product waste while recovering some of its stored energy is of interest for the cost reduction of nitrogen for use in industrial processes. Current devices may waste up to 30% of the gaseous nitrogen product by venting it to atmosphere. Furthermore, no attempt is made to recover the thermal energy available in the coldness of the cryogen. A seven step cycle with changing volumes and ambient heat addition is proposed, eliminating all product waste and providing the means of energy recovery from the nitrogen. This thesis discusses the new thermodynamic cycle and modeling as well as the mechanical design and testing of a prototype device. The prototype was able to achieve liquid nitrogen vaporization and pressurization up to 1000 psi, while full cycle validation is ongoing with promising initial results.

Conical evaporator and liquid-return wick model for vapor anode, multi-tube AMTEC cells

Science.gov (United States)

Tournier, Jean-Michel; El-Genk, Mohamed S.

2000-01-01

A detailed, 2-D thermal-hydraulic model for conical and flat evaporators and the liquid sodium return artery in PX-type AMTEC cells was developed, which predicts incipient dryout at the evaporator wick surface. Results obtained at fixed hot and cold side temperatures showed that the flat evaporator provided a slightly lower vapor pressure, but reached the capillary limit at higher temperature. The loss of performance due to partial recondensation over up to 20% of the wick surface of the deep conical evaporators was offset by the larger surface area available for evaporation, providing a slightly higher vapor pressure. Model results matched the PX-3A cell's experimental data of electrical power output, but the predicted temperature of the cell's conical evaporator was consistently ~50 K above measurements. A preliminary analysis indicated that sodium vapor leakage in the cell (through microcracks in the BASE tubes' walls or brazes) may explain the difference between predicted and measured evaporator temperatures in PX-3A. .

Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

Energy Technology Data Exchange (ETDEWEB)

Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S. [Lawrence Berkeley National Lab., CA (United States)

1997-12-31

This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

Method And Apparatus For Atomizing And Vaporizing Liquid

KAUST Repository

Lal, Amit; Mayet, Abdulilah M.

2014-01-01

A method and apparatus for atomizing and vaporizing liquid is described. An apparatus having an ejector configured to eject one or more droplets of liquid may be inserted into a reservoir containing liquid. The ejector may have a vibrating device that vibrates the ejector and causes liquid to move from the reservoir up through the ejector and out through an orifice located on the top of the ejector. The one or more droplets of liquid ejected from the ejector may be heated and vaporized into the air.

Method And Apparatus For Atomizing And Vaporizing Liquid

KAUST Repository

Lal, Amit

2014-09-18

A method and apparatus for atomizing and vaporizing liquid is described. An apparatus having an ejector configured to eject one or more droplets of liquid may be inserted into a reservoir containing liquid. The ejector may have a vibrating device that vibrates the ejector and causes liquid to move from the reservoir up through the ejector and out through an orifice located on the top of the ejector. The one or more droplets of liquid ejected from the ejector may be heated and vaporized into the air.

Apparatus of vaporizing and condensing liquid radioactive wastes and its operation method

International Nuclear Information System (INIS)

Irie, Hiromitsu; Tajima, Fumio.

1975-01-01

Object: To prevent corrosion of material for a vapor-condenser and a vapor heater and to prevent radioactive contamination of heated vapor. Structure: Liquid waste is fed from a liquid feeding tank to a vapor-condenser to vaporize and condense the waste. Uncondensed liquid waste, which is not in a level of a given density, is temporally stored in a batch tank through a switching valve and a pipe. Prior to successive feeding from the liquid feeding tank, the uncondensed liquid waste within the batch tank is returned by a return pump to the condenser, after which a new liquid is fed from the liquid feeding tank for re-vaporization and condensation in the vapor-condenser. Then, similar operation is repeated until the uncondensed liquid waste assumes a given density, and when the uncondensed liquid waste reaches a given density, the condensed liquid waste is discharged into the storage tank through the switching valve. (Ohara, T.)

Generalized correlation of latent heats of vaporization of coal liquid model compounds between their freezing points and critical points

Energy Technology Data Exchange (ETDEWEB)

Sivaraman, A.; Kobuyashi, R.; Mayee, J.W.

1984-02-01

Based on Pitzer's three-parameter corresponding states principle, the authors have developed a correlation of the latent heat of vaporization of aromatic coal liquid model compounds for a temperature range from the freezing point to the critical point. An expansion of the form L = L/sub 0/ + ..omega..L /sub 1/ is used for the dimensionless latent heat of vaporization. This model utilizes a nonanalytic functional form based on results derived from renormalization group theory of fluids in the vicinity of the critical point. A simple expression for the latent heat of vaporization L = D/sub 1/epsilon /SUP 0.3333/ + D/sub 2/epsilon /SUP 0.8333/ + D/sub 4/epsilon /SUP 1.2083/ + E/sub 1/epsilon + E/sub 2/epsilon/sup 2/ + E/sub 3/epsilon/sup 3/ is cast in a corresponding states principle correlation for coal liquid compounds. Benzene, the basic constituent of the functional groups of the multi-ring coal liquid compounds, is used as the reference compound in the present correlation. This model works very well at both low and high reduced temperatures approaching the critical point (0.02 < epsilon = (T /SUB c/ - T)/(T /SUB c/- 0.69)). About 16 compounds, including single, two, and three-ring compounds, have been tested and the percent root-mean-square deviations in latent heat of vaporization reported and estimated through the model are 0.42 to 5.27%. Tables of the coefficients of L/sub 0/ and L/sub 1/ are presented. The contributing terms of the latent heat of vaporization function are also presented in a table for small increments of epsilon.

Nuclear material inventory estimation in solvent extraction contactors

International Nuclear Information System (INIS)

Beyerlein, A.; Geldard, J.

1986-06-01

This report describes the development of simple nuclear material (uranium and plutonium) inventory relations for mixer-settler solvent extraction contactors used in reprocessing spent nuclear fuels. The relations are developed for light water reactor fuels where the organic phase is 30% tri-n-butylphosphate (TBP) by volume. For reprocessing plants using mixer-settler contactors as much as 50% of the nuclear material within the contactors is contained in A type (aqueous to organic extraction) contactors. Another very significant portion of the contactor inventory is in the partitioning contactors. The stripping contactors contain a substantial uranium inventory but contain a very small plutonium inventory (about 5 to 10% of the total contactor inventory). The simplified inventory relations developed in this work for mixer-settler contactors reproduce the PUBG databases within about a 5% standard deviation. They can be formulated to explicitly show the dependence of the inventory on nuclear material concentrations in the aqueous feed streams. The dependence of the inventory on contactor volumes, phase volume ratios, and acid and TBP concentrations are implicitly contained in parameters that can be calculated for a particular reprocessing plant from nominal flow sheet data. The terms in the inventory relations that represent the larger portion of the inventory in A type and partitioning contactors can be extended to pulsed columns virtually without change

Assembly of contactors-separators in an extraction unit

International Nuclear Information System (INIS)

Beaujard, Jean; Menes, J.-C.; Ravoire, Jean.

1977-01-01

A description is given of an assembly of contactors-separators of an installation in which a transfer of mass or an isotope exchange occurs between two non miscible phases, characterized in that the contactors-separators are associated in m lines and n columns, one of the phases issuing from a contactor-separator being sent directly to the next contactor-separator of the same line, whilst the other phase, issuing from the same contactor-separator is sent directly to the next contactor-separator of the same column, each of the m lines and n columns being provided with one only pumping facility, the instantaneous flow rate of each phase, at the intake and outlet of each contactor-separator being appreciably identical [fr

Experimental vapor-liquid equilibria data for binary mixtures of xylene isomers

Directory of Open Access Journals (Sweden)

W.L. Rodrigues

2005-09-01

Full Text Available Separation of aromatic C8 compounds by distillation is a difficult task due to the low relative volatilities of the compounds and to the high degree of purity required of the final commercial products. For rigorous simulation and optimization of this separation, the use of a model capable of describing vapor-liquid equilibria accurately is necessary. Nevertheless, experimental data are not available for all binaries at atmospheric pressure. Vapor-liquid equilibria data for binary mixtures were isobarically obtained with a modified Fischer cell at 100.65 kPa. The vapor and liquid phase compositions were analyzed with a gas chromatograph. The methodology was initially tested for cyclo-hexane+n-heptane data; results obtained are similar to other data in the literature. Data for xylene binary mixtures were then obtained, and after testing, were considered to be thermodynamically consistent. Experimental data were regressed with Aspen Plus® 10.1 and binary interaction parameters were reported for the most frequently used activity coefficient models and for the classic mixing rules of two cubic equations of state.

Vapor liquid fraction determination

International Nuclear Information System (INIS)

1980-01-01

This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)

Vapor-liquid equilibrium for the system ethyl alcohol + ester; Equilibrio liquido-vapor para o sistema alcool etilico+ester

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Humberto Neves Maia de; Nascimento, Yuri Corsino do; Chiavone-Filho, Osvaldo [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2004-07-01

This work consists of the experimental determination of a series of vapor-liquid equilibrium (VLE) data, for mixtures of ethyl alcohol + ester (ethyl acetate), prepared synthetically, that may be present in the production of biodiesel. The separation of the ethyl alcohol from esters by distillation is an important stage of this process, and therefore it demands accurate data for an appropriate modelling, and later optimization via simulators. FISCHER'S ebulliometer, with digital control (Model 602), was used for measurement of VLE data for the system ethyl alcohol + ester. It consists of a recirculation cell of the both vapor and liquid phases, providing complete data, i.e., pressure, temperature and compositions of the liquid and vapor phases that were obtained by gaseous chromatography (PTxy). This apparatus is coupled to a thermostatic bath with cooling (TE-184 TECNAL) that aims to condense the coming steams of the ebullition in order to return to the mixture camera. The VLE data obtained experimentally were submitted to the test of thermodynamic consistence of the deviations, where the equation of Gibbs-Duhem is used, through the model UNIQUAC. The parameters obtained from the experimental data can be applied in the simulators of processes with the purpose of optimizing the separation of the ethyl alcohol of Ester. (author)

Small-scale experimental study of vaporization flux of liquid nitrogen released on water.

Science.gov (United States)

Gopalaswami, Nirupama; Olewski, Tomasz; Véchot, Luc N; Mannan, M Sam

2015-10-30

A small-scale experimental study was conducted using liquid nitrogen to investigate the convective heat transfer behavior of cryogenic liquids released on water. The experiment was performed by spilling five different amounts of liquid nitrogen at different release rates and initial water temperatures. The vaporization mass fluxes of liquid nitrogen were determined directly from the mass loss measured during the experiment. A variation of initial vaporization fluxes and a subsequent shift in heat transfer mechanism were observed with changes in initial water temperature. The initial vaporization fluxes were directly dependent on the liquid nitrogen spill rate. The heat flux from water to liquid nitrogen determined from experimental data was validated with two theoretical correlations for convective boiling. It was also observed from validation with correlations that liquid nitrogen was found to be predominantly in the film boiling regime. The substantial results provide a suitable procedure for predicting the heat flux from water to cryogenic liquids that is required for source term modeling. Copyright © 2015 Elsevier B.V. All rights reserved.

Isolation contactor state control system

Energy Technology Data Exchange (ETDEWEB)

Bissontz, Jay E.

2017-05-16

A controller area network (CAN) installed on a hybrid electric vehicle provides one node with control of high voltage power distribution system isolation contactors and the capacity to energize a secondary electro-mechanical relay device. The output of the secondary relay provides a redundant and persistent backup signal to the output of the node. The secondary relay is relatively immune to CAN message traffic interruptions and, as a result, the high voltage isolation contactor(s) are less likely to transition open in the event that the intelligent output driver should fail.

A modified free-volume-based model for predicting vapor-liquid and solid-liquid equilibria for size asymmetric systems

DEFF Research Database (Denmark)

Radfarnia, H.R.; Ghotbi, C.; Taghikhani, V.

2005-01-01

The main purpose of this work is to present a free-volume combinatorial term in predicting vapor-liquid equilibrium (VLE) and solid-liquid equilibrium (SLE) of polymer/solvent and light and heavy hydrocarbon/hydrocarbon mixtures. The proposed term is based on a modification of the original Freed ...

On the vapor-liquid equilibrium in hydroprocessing reactors

Energy Technology Data Exchange (ETDEWEB)

Chen, J.; Munteanu, M.; Farooqi, H. [National Centre for Upgrading Technology, Devon, AB (Canada)

2009-07-01

When petroleum distillates undergo hydrotreating and hydrocracking, the feedstock and hydrogen pass through trickle-bed catalytic reactors at high temperatures and pressures with large hydrogen flow. As such, the oil is partially vaporized and the hydrogen is partially dissolved in liquid to form a vapor-liquid equilibrium (VLE) system with both vapor and liquid phases containing oil and hydrogen. This may result in considerable changes in flow rates, physical properties and chemical compositions of both phases. Flow dynamics, mass transfer, heat transfer and reaction kinetics may also be modified. Experimental observations of VLE behaviours in distillates with different feedstocks under a range of operating conditions were presented. In addition, VLE was predicted along with its effects on distillates in pilot and commercial scale plants. tabs., figs.

Development of centrifugal contactors [Paper No. : IIIB-5

International Nuclear Information System (INIS)

Koganti, S.B.; Nagarajan, S.; Balasubramanian, G.R.

1979-01-01

Development of short residence contactors is one of the main objectives of Reprocessing Programme for fast reactor fuels in Reactor Research Centre, Kalpakkam. Paper discusses the suitability of centrifugal contactor as one of the candidate solvent contactors. Description of various stages of development of this work in the Reprocessing Development Laboratory, RRC and also characteristics of small contactor developed are given. (author)

Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model.

Science.gov (United States)

Bauer, Brad A; Patel, Sandeep

2009-08-28

We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of T(c)=623 K, rho(c)=0.351 g/cm(3), and P(c)=250.9 atm, which are in good agreement with experimental values of T(c)=647.1 K, rho(c)=0.322 g/cm(3), and P(c)=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (T(c)=631 K and rho(c)=0.308 g/cm(3)). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300-450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase

The performance of simulated annealing in parameter estimation for vapor-liquid equilibrium modeling

Directory of Open Access Journals (Sweden)

A. Bonilla-Petriciolet

2007-03-01

Full Text Available In this paper we report the application and evaluation of the simulated annealing (SA optimization method in parameter estimation for vapor-liquid equilibrium (VLE modeling. We tested this optimization method using the classical least squares and error-in-variable approaches. The reliability and efficiency of the data-fitting procedure are also considered using different values for algorithm parameters of the SA method. Our results indicate that this method, when properly implemented, is a robust procedure for nonlinear parameter estimation in thermodynamic models. However, in difficult problems it still can converge to local optimums of the objective function.

Stability limit of liquid water in metastable equilibrium with subsaturated vapors.

Science.gov (United States)

Wheeler, Tobias D; Stroock, Abraham D

2009-07-07

A pure liquid can reach metastable equilibrium with its subsaturated vapor across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated vapor) is compensated by a difference in pressure between the phases. To equilibrate with subsaturated vapor, the liquid phase assumes a pressure that is lower than its standard vapor pressure, such that the liquid phase is metastable with respect to the vapor phase. For sufficiently subsaturated vapors, the liquid phase can even assume negative pressures. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in pressure between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as vapor-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with vapors of activity aw,vapairhumiditynucleation theory or molecular simulations (Pcav=-140 to -180 MPa). To determine the cause of the disparity between the observed and predicted stability limit, we examine experimentally the likelihood of several nonhomogeneous mechanisms of nucleation: (i) heterogeneous nucleation caused by hydrophobic patches on void walls, (ii) nucleation caused by the presence of dissolved solute, (iii) nucleation caused by the presence of pre-existing vapor nuclei, and (iv) invasion of air through the hydrogel membrane into the voids. We conclude that, of these possibilities, (i) and (ii) cannot be discounted, whereas (iii) and (iv) are unlikely to play a role in determining the stability limit.

Multiphase flow modeling of molten material-vapor-liquid mixtures in thermal nonequilibrium

International Nuclear Information System (INIS)

Park, Ik Kyu; Park, Goon Cherl; Bang, Kwang Hyun

2000-01-01

This paper presents a numerical model of multiphase flow of the mixtures of molten material-liquid-vapor, particularly in thermal nonequilibrium. It is a two-dimensional, transient, three-fluid model in Eulerian coordinates. The equations are solved numerically using the finite difference method that implicitly couples the rates of phase changes, momentum, and energy exchange to determine the pressure, density, and velocity fields. To examine the model's ability to predict an experimental data, calculations have been performed for tests of pouring hot particles and molten material into a water pool. The predictions show good agreement with the experimental data. It appears, however, that the interfacial heat transfer and breakup of molten material need improved models that can be applied to such high temperature, high pressure, multiphase flow conditions

(Vapor + liquid + liquid) equilibrium measurements and correlation for {1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a)} system

International Nuclear Information System (INIS)

Zhao, Yanxing; Gong, Maoqiong; Dong, Xueqiang; Guo, Hao; Wu, Jianfeng

2014-01-01

Highlights: • VLLE data for the (R134 + R600a) system at temperatures ranging from (235.311 to 241.720) K was measured. • The experiment was carried out using an apparatus based on the recirculation of vapor into liquid. • Correlation of VLE data was made using PR−HV−NRTL model. • A strong critical opalescence was observed. - Abstract: In this work, a study on the (vapor + liquid + liquid) equilibrium (VLLE) for the (R134 + R600a) system was carried out using an apparatus based on the recirculation of vapor into liquid at temperatures ranging from (235.311 to 241.720) K. The uncertainties of the composition, temperature, and pressure were less than ±0.005, ±5 mK and ±0.5 kPa, respectively. Thirty-eight experimental p–T–x data covering both branches of the binodal boundary and nineteen experimental p–T–y data were presented. Three numerical methods were used to obtain the second liquid phase compositions coexisting in equilibrium, and all the three methods lead to consistent results. Moreover, all of the experimental data were correlated by the Peng–Robinson equation of state (PR EoS) with the Huron–Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient model. Then the vapor phase compositions were calculated. The results show good agreement with the experimental data, and the maximum deviation is less than 0.006

Deviations from mass transfer equilibrium and mathematical modeling of mixer-settler contactors

International Nuclear Information System (INIS)

Beyerlein, A.L.; Geldard, J.F.; Chung, H.F.; Bennett, J.E.

1980-01-01

This paper presents the mathematical basis for the computer model PUBG of mixer-settler contactors which accounts for deviations from mass transfer equilibrium. This is accomplished by formulating the mass balance equations for the mixers such that the mass transfer rate of nuclear materials between the aqueous and organic phases is accounted for. 19 refs

Quaternary isobaric (vapor + liquid + liquid) equilibrium and (vapor + liquid) equilibrium for the system (water + ethanol + cyclohexane + heptane) at 101.3 kPa

International Nuclear Information System (INIS)

Pequenin, Ana; Asensi, Juan Carlos; Gomis, Vicente

2011-01-01

Highlights: → Water-ethanol-cyclohexane-heptane and water-cyclohexane-heptane isobaric VLLE. → Isobaric experimental data were determined at 101.3 kPa. → A dynamic recirculating still with an ultrasonic homogenizer was used. → The quaternary system does not present quaternary azeotropes. - Abstract: Experimental isobaric (vapor + liquid + liquid) and (vapor + liquid) equilibrium data for the ternary system {water (1) + cyclohexane (2) + heptane (3)} and the quaternary system {water (1) + ethanol (2) + cyclohexane (3) + heptane (4)} were measured at 101.3 kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by Wisniak for testing the thermodynamic consistency of isobaric measurements was used to test the equilibrium data.

Testing of pyrochemical centrifugal contactors

International Nuclear Information System (INIS)

Chow, L.S.; Carls, E.L.; Basco, J.K.; Johnson, T.R.

1996-01-01

A centrifugal contactor that performs oxidation and reduction exchange reactions between molten metals and salts at 500 degrees Centigrade has been tested successfully at Argonne National Laboratory (ANL). The design is based on contactors for aqueous- organic systems operation near room temperature. In tests to demonstrate the performance of the pyrocontactor, cadmium and LICl-KCl eutectic salt were the immiscible solvent phases, and rare earths were the distributing solutes. The tests showed that the pyrocontactor mixed and separated the phases well, with stage efficiencies approaching 99% at rotor speeds near 2700 rpm. The contactor ran smoothly and reliably over the entire range of speeds that was tested

Characteristics of centrifugal rapid contactor, (3)

International Nuclear Information System (INIS)

Nakanishi, Mitsuo; Hirayama, Hiroshi; Takasu, Nobuyuki; Takeda, Hiroshi; Hoshino, Tadaya

1979-01-01

Organic solvent yields the degradation product as a result of irradiation, in the extraction process of spent fuel reprocessing. The development of a centrifugal rapid contactor is required for the reduction of the solvent degradation by shortening the contact time. The effects of fine solid particles were investigated with a SGN-Robatel LX-208N contactor, following the uranium extraction and re-extraction performance tests. It was found as the experimental result that the considerable quantity of solids accumulated in the rotor of the centrifugal contactor. As for this experimental apparatus, the flow diagram for the centrifugal rapid contactor and auxiliary apparatuses is shown, which are the same system used for the uranium extraction and re-extraction tests. The schematic diagram, the typical stage construction and fluid transfer path of the LX-208 contactor are illustrated. The main specifications of the LX-208 contactor are as follows: the internal diameter of a rotating bowl 200 mm, the material SUS 316, the number of stages 8, and the total hold-up volume of the contactor 1.8 l. Most tests were carried out with aqueous feed only, because white Alundum is easily deposited in the rotor, and the particle concentration in effluent stream becomes undetectable when organic and aqueous feeds are supplied simultaneously. As the experimental results, the correlation of Alundum concentration in effluent and running time, the effect of rotor speed on effluent stream concentration, the particle size distribution curves for No. 6000 and No. 8000 white Alundum, the effect of flow rate on effluent stream concentration and the effect of flow rate on particle size distribution for both No. 6000 and No. 8000 white Alundum are presented. (Nakai, Y.)

Sharing five years of pilot plant experience on aromatics extraction with ionic liquids

NARCIS (Netherlands)

Onink, S.A.F.; Hansmeier, A.R.; Meindersma, G.W.; Haan, de A.B.

2011-01-01

Since 2004 pilot plant trials have been conducted with various contactors and different ionic liquids for petrochemical model feeds as well as real refinery feeds. Our pilot plant contains several columns (rotating disc contactor, Kuhni, pulsed disc and donut column) with a height of 6 m and 5 cm

Solvent extraction studies in miniature centrifugal contactors

International Nuclear Information System (INIS)

Siczek, A.A.; Meisenhelder, J.H.; Bernstein, G.J.; Steindler, M.J.

1980-01-01

A miniature short-residence-time centrifugal solvent extraction contactor and an eight-stage laboratory minibank of centrifugal contactors were used for testing the possibility of utilizing kinetic effects for improving the separation of uranium from ruthenium and zirconium in the Purex process. Results of these tests showed that a small improvement found in ruthenium and zirconium decontamination in single-stage solvent extraction tests was lost in the multistage extraction tests- in fact, the extent of saturation of the solvent by uranium, rather than the stage residence time, controlled the extent of ruthenium and zirconium extraction. In applying the centrifugal contactor to the Purex process, the primary advantages would be less radiolytic damage to the solvent, high troughput, reduced solvent inventory, and rapid attainment of steady-state operating conditions. The multistage mini contactor was also tested to determine the suitability of short-residence-time contactors for use with the Civex and Thorex processes and was found to be compatible with the requirements of these processes. (orig.) [de

Thermodynamic and transport properties of sodium liquid and vapor

International Nuclear Information System (INIS)

Fink, J.K.; Leibowitz, L.

1995-01-01

Data have been reviewed to obtain thermodynamically consistent equations for thermodynamic and transport properties of saturated sodium liquid and vapor. Recently published Russian recommendations and results of equation of state calculations on thermophysical properties of sodium have been included in this critical assessment. Thermodynamic properties of sodium liquid and vapor that have been assessed include: enthalpy, heat capacity at constant pressure, heat capacity at constant volume, vapor pressure, boiling point, enthalpy of vaporization, density, thermal expansion, adiabatic and isothermal compressibility, speed of sound, critical parameters, and surface tension. Transport properties of liquid sodium that have been assessed include: viscosity and thermal conductivity. For each property, recommended values and their uncertainties are graphed and tabulated as functions of temperature. Detailed discussions of the analyses and determinations of the recommended equations include comparisons with recommendations given in other assessments and explanations of consistency requirements. The rationale and methods used in determining the uncertainties in the recommended values are also discussed

Vapor-Liquid Equilibrium of Methane with Water and Methanol. Measurements and Modeling

DEFF Research Database (Denmark)

Frost, Michael Grynnerup; Karakatsani, Eirini; von Solms, Nicolas

2014-01-01

that rely on phase equilibrium data for optimization. The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols, and water. New vapor-liquid equilibrium data are reported for methane + water, methane + methanol, and methane + methanol...

Diffuse scattering from the liquid-vapor interfaces of dilute Bi:Ga, Tl:Ga, and Pb:Ga alloys

International Nuclear Information System (INIS)

Li Dongxu; Jiang Xu; Rice, Stuart A.; Lin Binhua; Meron, Mati

2005-01-01

As part of a study of the in-plane wave-vector (q xy ) dependence of the effective Hamiltonian for the liquid-vapor interface, H(q), the wave-vector dependences of diffuse x-ray scattering from the liquid-vapor interfaces of dilute alloys of Bi in Ga, Tl in Ga, and Pb in Ga have been measured. In these dilute alloys the solute component segregates as a monolayer that forms the outermost stratum of the liquid-vapor interfaces, and the density distribution along the normal to the interface is stratified. Over the temperature ranges that the alloy interfaces were studied, the Tl and Pb monolayers exhibit both crystalline and liquid phases while the Bi monolayer is always liquid. The diffuse scattering from the liquid-vapor interfaces of these alloys displays interesting differences with that from the liquid-vapor interface of pure Ga. The presence of a segregated monolayer of solute in the liquid-vapor interface of the alloy appears to slightly suppress the fluctuations in an intermediate wave-vector range in a fashion that preserves the validity of the macroscopic capillary wave model to smaller wavelengths than in pure liquid Ga, and there is an increase in diffuse scattering when the Tl and Pb monolayers melt. The surface intrinsic roughness from fitting the wave-vector dependence of surface tension is 5.0 pm for the Tl:Ga alloy and 1.4 pm for the Bi:Ga alloy. Also, a mode of excitation that contributes to diffuse scattering from the liquid-vapor interface of Pb in Ga, but does not contribute to diffuse scattering from the liquid-vapor interface of Ga, has been identified. It is proposed that this mode corresponds to the separation of the Pb and Ga layers in the regime 1 nm -1 ≤q xy ≤10 nm -1

Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures

Directory of Open Access Journals (Sweden)

B. A. Mandagarán

2006-03-01

Full Text Available A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the correlation shows a good agreement for binary and ternary data. The correlation also shows good prediction for reactive quaternary data.

Synchrotron X-ray studies of liquid-vapor interfaces

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage

1986-01-01

The density profile ρ(z) across a liquid-vapor interface may be determined by the reflectivity R(θ) of X-rays at grazing angle incidence θ. The relation between R(θ) and ρ(z) is discussed, and experimental examples illustrating thermal roughness of simple liquids and smectic layering of liquid...

Gibbs Ensemble Simulation on Polarizable Models: Vapor-liquid Equilibrium in Baranyai-Kiss Models of Water

Czech Academy of Sciences Publication Activity Database

Moučka, F.; Nezbeda, Ivo

2013-01-01

Roč. 360, DEC 25 (2013), s. 472-476 ISSN 0378-3812 Grant - others:GA MŠMT(CZ) LH12019 Institutional support: RVO:67985858 Keywords : multi-particle move monte carlo * Gibbs ensemble * vapor-liquid-equilibria Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.241, year: 2013

Efficiency of contactors

International Nuclear Information System (INIS)

Orth, D.A.; Graham, F.R.; Holt, D.L.

1986-01-01

The Savannah River Plant has two separations plants that began Purex operations in 1954 and 1955 with pump-mix mixer-settlers as contactors to process nuclear fuels. The only changes to the extraction equipment were replacement of most of the mixer-settlers in one plant with larger units in 1959, and the further replacement of the large 1A bank with a bank of rapid-contact centrifugal contactors in 1966. Improved performance of the old units has become highly desirable, and an experimental program is underway. Good contact between the phases, and adequate settling without entrainment of the opposite phase are required for high efficiency operation of the mixer-settlers. Factors that determine efficiency are mixer design, drop size generated, and phase coalescence properties. The original development work and accumulated plant data confirm that the tip speed of a given impeller design determines the throughput capacity and extraction performance. An experimental unit with three full-scale stages has been constructed and is being utilized to test different impeller designs; reduced pumping and better mixing with lower speeds appear to be the key factors for improvement. Decontamination performance of the rapid-contact centrifugal contactors is limited by the number of scrub contacts and the time of contact because of slowly equilibrating fission product species. Where solvent degradation is not a factor, the longer scrub contact of mixer-settlers gives better decontamination than the centrifugals. This kinetic effect can be overcome with long scrub contacts that follow the initial short extraction and short scrub contacts in the centrifugal contactors. A hybrid experimental unit with both rapid contact sections and longer contact scrub sections is under development to establish the degree of improvement that might be attained

Theoretical approaches and experimental evidence for liquid-vapor phase transitions in nuclei

Energy Technology Data Exchange (ETDEWEB)

Moretto, L.G.; Elliott, J.B.; Phair, L.; Wozniak, G.J.; Mader, C.M.; Chappars, A.

2001-01-01

The leptodermous approximation is applied to nuclear systems for T > 0. The introduction of surface corrections leads to anomalous caloric curves and to negative heat capacities in the liquid-gas coexistence region. Clusterization in the vapor is described by associating surface energy to clusters according to Fisher's formula. The three-dimensional Ising model, a leptodermous system par excellence, does obey rigorously Fisher's scaling up to the critical point. Multifragmentation data from several experiments including the ISiS and EOS Collaborations, as well as compound nucleus fragment emission at much lower energy follow the same scaling, thus providing the strongest evidence yet of liquid-vapor coexistence.

Development of robust fluorinated TiO2/PVDF composite hollow fiber membrane for CO2 capture in gas-liquid membrane contactor

Science.gov (United States)

Lin, Yuqing; Xu, Yilin; Loh, Chun Heng; Wang, Rong

2018-04-01

Gas-liquid membrane contactor (GLMC) is a promising method to attain high efficiency for CO2 capture from flue gas, biogas and natural gas. However, membranes used in GLMC are prone to pore wetting due to insufficient hydrophobicity and low chemical resistance, resulting in significant increase in mass transfer resistance. To mitigate this issue, inorganic-organic fluorinated titania/polyvinylidene fluoride (fTiO2/PVDF) composite hollow fiber (HF) membranes was prepared via facile in-situ vapor induced hydrolyzation method, followed by hydrophobic modification. The proposed composite membranes were expected to couple the superb chemical stability of inorganic and high permeability/low cost of organic materials. The continuous fTiO2 layer deposited on top of PVDF substrate was found to possess a tighter microstructure and better hydrophobicity, which effectively prevented the membrane from wetting and lead to a high CO2 absorption flux (12.7 × 10-3 mol m-2 s-1). In a stability test with 21-day operation of GLMC using 1M monoethanolamine (MEA) as the absorbent, the fTiO2/PVDF membrane remained to be intact with a CO2 absorption flux decline of ∼16%, while the pristine PVDF membrane suffered from a flux decline of ∼80% due to membrane damage. Overall, this work provides an insight into the preparation of high-quality inorganic/organic composite HF membranes for CO2 capture in GLMC application.

The influence of liquid/vapor phase change onto the Nusselt number

Science.gov (United States)

Popescu, Elena-Roxana; Colin, Catherine; Tanguy, Sebastien

2017-11-01

In spite of its significant interest in various fields, there is currently a very few information on how an external flow will modify the evaporation or the condensation of a liquid surface. Although most applications involve turbulent flows, the simpler configuration where a laminar superheated or subcooled vapor flow is shearing a saturated liquid interface has still never been solved. Based on a numerical approach, we propose to characterize the interaction between a laminar boundary layer of a superheated or subcooled vapor flow and a static liquid pool at saturation temperature. By performing a full set of simulations sweeping the parameters space, correlations are proposed for the first time on the Nusselt number depending on the dimensionless numbers that characterize both vaporization and condensation. As attended, the Nusselt number decreases or increases in the configurations involving respectively vaporization or condensation. More unexpected is the behaviour of the friction of the vapor flow on the liquid pool, for which we report that it is weakly affected by the phase change, despite the important variation of the local flow structure due to evaporation or condensation.

A Scale for Rating Fire-Prevention Contactors

Science.gov (United States)

M.L. Doolittle

1979-01-01

A scale is constructed to help fire-prevention program administrators determine if an individual contactor is effective at influencing people. The 24 items in the scale indicate the qualities that an effective contactor should have.

Apparatus to measure vapor pressure, differential vapor pressure, liquid molar volume, and compressibility of liquids and solutions to the critical point. Vapor pressures, molar volumes, and compressibilities of protiobenzene and deuteriobenzene at elevated temperatures

International Nuclear Information System (INIS)

Kooner, Z.S.; Van Hook, W.A.

1986-01-01

An apparatus designed to measure vapor pressure differences between two similar liquids, such as isotopic isomers, or between a solution and its reference solvent at temperatures and pressures extending to the critical point is described. Vapor-phase volume is minimized and pressure is transmitted to the transducer through the liquid, thereby avoiding several experimental difficulties. Liquid can be injected into the heated part of the system by volumetrically calibrated screw injectors, thus permitting measurements of liquid molar volume, compressibility, and expansivity. The addition of a high-pressure circulating pump and injection valve allows the apparatus to be employed as a continuous dilution differential vapor pressure apparatus for determining partial molar free energies of solution. In the second part of the paper data on the vapor pressure, molar volume, compressibility, and expansivity and their isotope effects for C 6 H 6 and C 6 D 6 from room temperature to near the critical temperature are reported

Navier slip model of drag reduction by Leidenfrost vapor layers

KAUST Repository

Berry, Joseph D.

2017-10-17

Recent experiments found that a hot solid sphere that is able to sustain a stable Leidenfrost vapor layer in a liquid exhibits significant drag reduction during free fall. The variation of the drag coefficient with Reynolds number deviates substantially from the characteristic drag crisis behavior at high Reynolds numbers. Measurements based on liquids of different viscosities show that the onset of the drag crisis depends on the viscosity ratio of the vapor to the liquid. Here we attempt to characterize the complexity of the Leidenfrost vapor layer with respect to its variable thickness and possible vapor circulation within, in terms of the Navier slip model that is defined by a slip length. Such a model can facilitate tangential flow and thereby alter the behavior of the boundary layer. Direct numerical and large eddy simulations of flow past a sphere at moderate to high Reynolds numbers (102≤Re≤4×104) are employed to quantify comparisons with experimental results, including the drag coefficient and the form of the downstream wake on the sphere. This provides a simple one parameter characterization of the drag reduction phenomenon due to a stable vapor layer that envelops a solid body.

Navier slip model of drag reduction by Leidenfrost vapor layers

KAUST Repository

Berry, Joseph D.; Vakarelski, Ivan Uriev; Chan, Derek Y. C.; Thoroddsen, Sigurdur T

2017-01-01

Recent experiments found that a hot solid sphere that is able to sustain a stable Leidenfrost vapor layer in a liquid exhibits significant drag reduction during free fall. The variation of the drag coefficient with Reynolds number deviates substantially from the characteristic drag crisis behavior at high Reynolds numbers. Measurements based on liquids of different viscosities show that the onset of the drag crisis depends on the viscosity ratio of the vapor to the liquid. Here we attempt to characterize the complexity of the Leidenfrost vapor layer with respect to its variable thickness and possible vapor circulation within, in terms of the Navier slip model that is defined by a slip length. Such a model can facilitate tangential flow and thereby alter the behavior of the boundary layer. Direct numerical and large eddy simulations of flow past a sphere at moderate to high Reynolds numbers (102≤Re≤4×104) are employed to quantify comparisons with experimental results, including the drag coefficient and the form of the downstream wake on the sphere. This provides a simple one parameter characterization of the drag reduction phenomenon due to a stable vapor layer that envelops a solid body.

Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

Energy Technology Data Exchange (ETDEWEB)

Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)

1998-01-01

In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.

Science.gov (United States)

Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

2008-01-01

Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application.

Comparison of cryopreserved human sperm in vapor and liquid phases of liquid nitrogen: effect on motility parameters, morphology, and sperm function.

Science.gov (United States)

Punyatanasakchai, Piyaphan; Sophonsritsuk, Areephan; Weerakiet, Sawaek; Wansumrit, Surapee; Chompurat, Deonthip

2008-11-01

To compare the effects of cryopreserved sperm in vapor and liquid phases of liquid nitrogen on sperm motility, morphology, and sperm function. Experimental study. Andrology laboratory at Ramathibodi Hospital, Thailand. Thirty-eight semen samples with normal motility and sperm count were collected from 38 men who were either patients of an infertility clinic or had donated sperm for research. Each semen sample was divided into two aliquots. Samples were frozen with static-phase vapor cooling. One aliquot was plunged into liquid nitrogen (-196 degrees C), and the other was stored in vapor-phase nitrogen (-179 degrees C) for 3 days. Thawing was performed at room temperature. Motility was determined by using computer-assisted semen analysis, sperm morphology was determined by using eosin-methylene blue staining, and sperm function was determined by using a hemizona binding test. Most of the motility parameters of sperm stored in the vapor phase were not significantly different from those stored in the liquid phase of liquid nitrogen, except in amplitude of lateral head displacement. The percentages of normal sperm morphology in both vapor and liquid phases also were not significantly different. There was no significant difference in the number of bound sperm in hemizona between sperm cryopreserved in both vapor and liquid phases of liquid nitrogen. Cryopreservation of human sperm in a vapor phase of liquid nitrogen was comparable to cryopreservation in a liquid phase of liquid nitrogen.

Water-saving liquid-gas conditioning system

Science.gov (United States)

Martin, Christopher; Zhuang, Ye

2014-01-14

A method for treating a process gas with a liquid comprises contacting a process gas with a hygroscopic working fluid in order to remove a constituent from the process gas. A system for treating a process gas with a liquid comprises a hygroscopic working fluid comprising a component adapted to absorb or react with a constituent of a process gas, and a liquid-gas contactor for contacting the working fluid and the process gas, wherein the constituent is removed from the process gas within the liquid-gas contactor.

A theoretical study of the growth of large sodium vapor bubbles in liquid sodium, including the effect of noncondensables and of vapor convection

International Nuclear Information System (INIS)

Casadei, F.; Donne, M.D.

1983-01-01

The study of the dynamics of the expansion of large bubbles of hot sodium vapor in a pool of liquid sodium plays an important role in understanding the effects of a hypothetical core disruptive accident. A model of the growth of the bubble in the pool is described. The equations of the motion of the liquid and of the nonsteady heat diffusion problem are solved together with the continuity and energy equations for the vapor phase. The first set of calculations has been performed with constant evaporation and condensation coefficients. In the second set, however, due account has been taken of the effect on condensation of noncondensable fission gases and vapor convection. Due to the very high calculated vapor velocities, noncondensable gases have little effect on the condensation rate, and the percentage amount of condensed sodium is considerably higher than previously calculated by other authors

Development of centrifugal contactor for FBR fuel reprocessing

International Nuclear Information System (INIS)

Washiya, Tadahiro; Takeuchi, Masayuki; Suganuma, Takashi; Aose, Shinichi; Ogino, Hideki

2003-01-01

In the Feasibility Study on Commercialized Fast Reactor Cycle Systems, the aqueous reprocessing technology is nominated as a candidate for future reprocessing system, which supposes to apply a centrifugal contactor in the extraction process. For the reprocessing plant, the centrifugal contactor has great advantages such as reducing solvent degradation, improving of equipment utilization rate, compact designing of equipment layout and critical safety domination. From these advantages, the centrifugal contactor is crucial equipment in the aqueous reprocessing process. Since 1985, JNC has been developing the centrifugal contactor. The single unit development has been accomplished and basic characteristics such as extraction performance, fluidic performance and remote maintenance performance have been determined. A durability test has been conducted for high longevity, with consideration given to the nitric acid mist and estimation of the equipment lifetime. System test equipment with centrifugal contactors of engineering scale was installed, and uranium test was conducted. Up to now, a standard flow sheet test in the extraction process and mal-operation test assuming the one stage shutdown condition have been performed. (author)

Development of a Power Electronics Unit for the Space Station Plasma Contactor

Science.gov (United States)

Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.

1994-01-01

A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

Distribution of binding energies of a water molecule in the water liquid-vapor interface

Energy Technology Data Exchange (ETDEWEB)

Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

2008-01-01

Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

TRACER-II: a complete computational model for mixing and propagation of vapor explosions

Energy Technology Data Exchange (ETDEWEB)

Bang, K.H. [School of Mechanical Engineering, Korea Maritime Univ., Pusan (Korea, Republic of); Park, I.G.; Park, G.C.

1998-01-01

A vapor explosion is a physical process in which very rapid energy transfer occurs between a hot liquid and a volatile, colder liquid when the two liquids come into a sudden contact. For the analyses of potential impacts from such explosive events, a computer program, TRACER-II, has been developed, which contains a complete description of mixing and propagation phases of vapor explosions. The model consists of fuel, fragmented fuel (debris), coolant liquid, and coolant vapor in two-dimensional Eulerian coordinates. The set of governing equations are solved numerically using finite difference method. The results of this numerical simulation of vapor explosions are discussed in comparison with the recent experimental data of FARO and KROTOS tests. When compared to some selected FARO and KROTOS data, the fuel-coolant mixing and explosion propagation behavior agree reasonably with the data, although the results are yet sensitive primarily to the melt breakup and fragmentation modeling. (author)

Quantitative liquid and vapor distribution measurements in evaporating fuel sprays using laser-induced exciplex fluorescence

International Nuclear Information System (INIS)

Fansler, Todd D; Drake, Michael C; Gajdeczko, Boguslaw; Düwel, Isabell; Koban, Wieland; Zimmermann, Frank P; Schulz, Christof

2009-01-01

Fully quantitative two-dimensional measurements of liquid- and vapor-phase fuel distributions (mass per unit volume) from high-pressure direct-injection gasoline injectors are reported for conditions of both slow and rapid vaporization in a heated, high-pressure spray chamber. The measurements employ the coevaporative gasoline-like fluorobenzene (FB)/diethylmethylamine (DEMA)/hexane exciplex tracer/fuel system. In contrast to most previous laser-induced exciplex-fluorescence (LIEF) experiments, the quantitative results here include regions in which liquid and vapor fuel coexist (e.g. near the injector exit). A unique aspect is evaluation of both vapor- and liquid-phase distributions at varying temperature and pressure using only in situ vapor-phase fluorescence calibration measurements at room temperature and atmospheric pressure. This approach draws on recent extensive measurements of the temperature-dependent spectroscopic properties of the FB–DEMA exciplex system, in particular on knowledge of the quantum efficiencies of the vapor-phase and liquid-phase (exciplex) fluorescence. In addition to procedures necessary for quantitative measurements, we discuss corrections for liquid–vapor crosstalk (liquid fluorescence that overlaps the vapor-fluorescence bandpass), the unknown local temperature due to vaporization-induced cooling, and laser-sheet attenuation by scattering and absorption

Calculating the enthalpy of vaporization for ionic liquid clusters.

Science.gov (United States)

Kelkar, Manish S; Maginn, Edward J

2007-08-16

Classical atomistic simulations are used to compute the enthalpy of vaporization of a series of ionic liquids composed of 1-alkyl-3-methylimidazolium cations paired with the bis(trifluoromethylsulfonyl)imide anion. The calculations show that the enthalpy of vaporization is lowest for neutral ion pairs. The enthalpy of vaporization increases by about 40 kJ/mol with the addition of each ion pair to the vaporizing cluster. Non-neutral clusters have much higher vaporization enthalpies than their neutral counterparts and thus are not expected to make up a significant fraction of volatile species. The enthalpy of vaporization increases slightly as the cation alkyl chain length increases and as temperature decreases. The calculated vaporization enthalpies are consistent with two sets of recent experimental measurements as well as with previous atomistic simulations.

Contacting gases and liquids

International Nuclear Information System (INIS)

Robinson, L.F.; Cahalan, M.J.

1980-01-01

A process is described for contacting substantially immiscible phases to transfer material from one phase to another, which comprises passing the phases through a contactor, while causing portions of at least one phase to be repeatedly passed through at least one other phase. One phase in the contactor is gaseous, and another liquid. A further phase can be liquid or solid The process may be used for extracting impurities from china clay, or extracting uranium values from ore with oxygen gas acting to oxidise the uranium. (author)

Physical model for vaporization

OpenAIRE

Garai, Jozsef

2006-01-01

Based on two assumptions, the surface layer is flexible, and the internal energy of the latent heat of vaporization is completely utilized by the atoms for overcoming on the surface resistance of the liquid, the enthalpy of vaporization was calculated for 45 elements. The theoretical values were tested against experiments with positive result.

Combination downflow-upflow vapor-liquid separator

Energy Technology Data Exchange (ETDEWEB)

Kidwell, John H. (Uniontown, OH); Prueter, William P. (Alliance, OH); Eaton, Andrew M. (Alliance, OH)

1987-03-10

An improved vapor-liquid separator having a vertically disposed conduit for flow of a mixture. A first, second and third plurality of curved arms penetrate and extend within the conduit. A cylindrical member is radially spaced from the conduit forming an annulus therewith and having perforations and a retaining lip at its upper end.

Molecular dynamics study on condensation/evaporation coefficients of chain molecules at liquid-vapor interface.

Science.gov (United States)

Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu

2015-07-07

The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.

Physical property, phase equilibrium, distillation. Measurement and prediction of vapor-liquid and liquid-liquid equilibria; Bussei / heiko / joryu. Kieki, ekieki heiko no sokutei to suisan

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K. [Nihon Univ., Tokyo (Japan)

1998-08-05

The data on vapor-liquid equilibrium are basic data indispensable to the designing of a distillation process. The stage required for separation depends greatly upon the x-y curve, and the existence/nonexistence of an azeotropic point is also an important item to be checked. This paper describes the measurement of vapor-liquid equilibrium and liquid-liquid equilibrium, and then introduces reliable data on vapor-liquid equilibrium and parameters of an activity coefficient formula. For the prediction of vapor-liquid equilibrium, the ASOG, UNIFAC, and modified NIFAC, all being group contributive methods are utilized. The differences between these group contributive methods are based on the differences between the contributive items based on the differences in size of molecules influencing the activity coefficients and the expression of the group activity coefficient formula. The applicable number of groups of the ASOG is 43, while that of groups of the UNIFAC is 50. The modified UNIFAC covers 43 groups. The prediction of liquid-liquid equilibrium by using a group contributive method has little progressed since the of the results of the study of Magnussen et al. using the UNIFAC. 12 refs., 8 figs., 1 tab.

Vapor-liquid equilibria for the acetone-ethanol-n-propanol-tert-butanol-water system

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K.; Uchida, K.; Kojima, K.

1981-12-01

This study deals with the measurement of vapor-liquid equilibria for the five-component system acetone-ethanol-n-propanol-tert-butanol-water at 760 mmHg and prediction of vapor-liquid equilibria by the ASOG group contribution method. The five-component system in this work is composed of a part of the components obtained during ethanol production by vapor-phase hydration of ethylene. 6 refs.

Contacting solids and liquids

International Nuclear Information System (INIS)

Robinson, L.F.

1980-01-01

A solids/liquid (or slurry/liquid) contactor is described comprising a container through which the phases flow, rotatable discs with a rotor dividing the container into a series of interconnected compartments and, in at least some of the compartments, receptacles extending between the discs to effect phase transfer. At least one of the compartments is free of receptacles or has receptacles arranged on a smaller diameter than in other compartments to form a settling chamber. The contactor may be used in the extraction of oil-sands or uranium or purification of china clay. (author)

Experimental study of the spill and vaporization of a volatile liquid

International Nuclear Information System (INIS)

Bohl, Douglas; Jackson, Gregory

2007-01-01

Pool and vapor cloud characteristics of an acetone spill issuing from the downstream wall of a flow obstruction oriented perpendicular to a uniform flow were investigated experimentally. Data indicate that the spill event was largely governed by the temperature of the surface in relation to the boiling point of the spilled liquid. The free stream velocity (ranging from 0.75 to 3.0 m/s) also impacted the spreading of the spill. Planar laser-induced fluorescence (PLIF) was used to measure acetone vapor concentrations during the transient pool spreading and vaporization in a window 60 cm long by 50 cm high and located downstream of the 16 cm high obstruction. The recirculation region induced by the flow obstruction caused upstream transport of the acetone vapor along the spill surface, after which it was convected vertically along the obstruction wall before being entrained into the flow and convected downstream. The recirculating flow caused regions of vapor within the flammability limits to be localized near the flow obstruction. These regions moved into and out of the measurement plane by large three-dimensional flow structures. The flammable region of the evolved vapor cloud was observed to grow well past the downstream edge of the measurement domain. With decreasing wind speeds, both the mass of acetone vapor within the flammability limits and the total spill event time increased significantly. The data presented herein provides a basis for validating future spill models of hazardous chemical releases, where complex turbulent flow modeling must be coupled with spill spreading and vaporization dynamics

Combination downflow-upflow vapor-liquid separator

Energy Technology Data Exchange (ETDEWEB)

Kidwell, J.H.; Prueter, W.P.; Eaton, A.M.

1987-03-10

An improved vapor-liquid separator is described having a vertically disposed conduit for flow of a mixture. A first, second and third plurality of curved arms penetrate and extend within the conduit. A cylindrical member is radially spaced from the conduit forming an annulus therewith and having perforations and a retaining lip at its upper end. 11 figs.

Sludge behavior in centrifugal contactor operation for nuclear fuel reprocessing

International Nuclear Information System (INIS)

Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Okamura, Nobuo; Koizumi, Kenji

2015-01-01

The Japan Atomic Energy Agency (JAEA) has been developing the centrifugal contactor for spent fuel reprocessing. In this study, we investigated the sludge behavior in centrifugal contactors at three different scales. The operational conditions (the flow rate and rotor speed) were varied. Most insoluble particles such as sludge remained in the rotor via centrifugal force. The capture ratio of sludge in the contactor was measured as a function of particle size at various flow rates, rotor speeds, and contactor scales. The sludge adhered and accumulated inside the rotor as the operational time increased, and the operational conditions influenced the capture ratio of the sludge; a lower flow rate and higher rotor speed increased the capture ratio. The results confirmed that Stokes' law can be applied to estimate the experimental result on the behavior of the capture ratio for centrifugal contactors with different scales. (author)

Modeling liquid hydrogen cavitating flow with the full cavitation model

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.B.; Qiu, L.M.; Qi, H.; Zhang, X.J.; Gan, Z.H. [Institute of Refrigeration and Cryogenic Engineering, Zhejiang University, Hangzhou 310027 (China)

2008-12-15

Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid hydrogen flow over a 2D hydrofoil and an axisymmetric ogive in Hord's reports with a so-called full cavitation model. The thermodynamic effect was demonstrated with the assumption of thermal equilibrium between the gas phase and liquid phase. Temperature-dependent fluid thermodynamic properties were specified along the saturation line from the ''Gaspak 3.2'' databank. Justifiable agreement between the computed surface pressure, temperature and experimental data of Hord was obtained. Specifically, a global sensitivity analysis is performed to examine the sensitivity of the turbulent computations to the wall grid resolution, wall treatments and changes in model parameters. A proper near-wall model and grid resolution were suggested. The full cavitation model with default model parameters provided solutions with comparable accuracy to sheet cavitation in liquid hydrogen for the two geometries. (author)

Student Understanding of Liquid-Vapor Phase Equilibrium

Science.gov (United States)

Boudreaux, Andrew; Campbell, Craig

2012-01-01

Student understanding of the equilibrium coexistence of a liquid and its vapor was the subject of an extended investigation. Written assessment questions were administered to undergraduates enrolled in introductory physics and chemistry courses. Responses have been analyzed to document conceptual and reasoning difficulties in sufficient detail to…

Dynamic behaviour of solvent contactors in fuel reprocessing plants- an analysis

Energy Technology Data Exchange (ETDEWEB)

Raju, R P; Siddiqui, H R [Nuclear Waste Management Group, Bhabha Atomic Research Centre, Mumbai (India); Murthy, K K; Kansra, V P [Fuel Reprocessing Group, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Fuel reprocessing plants carry out separation of useful fissile and fertile materials from spent nuclear fuels by isolating highly radioactive fission products using solvent extraction method. In the fuel reprocessing step of nuclear fuel cycle, optimisation of process parameters in the PUREX flowsheet design is of great importance particularly on account of the need to realize high degree of recovery of fissile and fertile materials and to ensure proper control on concentrations of fissile element in process streams for avoidance of criticality. In counter-current solvent contactors of PUREX flowsheet there are a variety of processes conditions which may cause plutonium accumulations that requires attention to ascertain safe Pu concentrations within the contactors. A study was carried out using the PUREX process mathematical model Solvent Extraction Program Having Interacting Solutes (SEPHIS) for pulsed solvent contactors in PREFRE-1, Tarapur and PREFRE-2, Kalpakkam flowsheets for optimising the process parameters in plutonium purification cycles. The study was extended to predict the behaviour of contactors handling plutonium bearing solutions under certain anticipated deviations in the process parameters. Modifications wherever necessary were carried out to the original SEPHIS code. This paper discusses the results obtained during this analysis. (author). 2 figs., 2 tabs.

Modelling and numerical simulation of liquid-vapor phase transitions; Modelisation et simulation numerique des transitions de phase liquide-vapeur

Energy Technology Data Exchange (ETDEWEB)

Caro, F

2004-11-15

This work deals with the modelling and numerical simulation of liquid-vapor phase transition phenomena. The study is divided into two part: first we investigate phase transition phenomena with a Van Der Waals equation of state (non monotonic equation of state), then we adopt an alternative approach with two equations of state. In the first part, we study the classical viscous criteria for selecting weak solutions of the system used when the equation of state is non monotonic. Those criteria do not select physical solutions and therefore we focus a more recent criterion: the visco-capillary criterion. We use this criterion to exactly solve the Riemann problem (which imposes solving an algebraic scalar non linear equation). Unfortunately, this step is quite costly in term of CPU which prevent from using this method as a ground for building Godunov solvers. That is why we propose an alternative approach two equations of state. Using the least action principle, we propose a phase changing two-phase flow model which is based on the second thermodynamic principle. We shall then describe two equilibrium submodels issued from the relaxations processes when instantaneous equilibrium is assumed. Despite the weak hyperbolicity of the last sub-model, we propose stable numerical schemes based on a two-step strategy involving a convective step followed by a relaxation step. We show the ability of the system to simulate vapor bubbles nucleation. (author)

On the critical temperature, normal boiling point, and vapor pressure of ionic liquids.

Science.gov (United States)

Rebelo, Luis P N; Canongia Lopes, José N; Esperança, José M S S; Filipe, Eduardo

2005-04-07

One-stage, reduced-pressure distillations at moderate temperature of 1-decyl- and 1-dodecyl-3-methylimidazolium bistriflilamide ([Ntf(2)](-)) ionic liquids (ILs) have been performed. These liquid-vapor equilibria can be understood in light of predictions for normal boiling points of ILs. The predictions are based on experimental surface tension and density data, which are used to estimate the critical points of several ILs and their corresponding normal boiling temperatures. In contrast to the situation found for relatively unstable ILs at high-temperature such as those containing [BF(4)](-) or [PF(6)](-) anions, [Ntf(2)](-)-based ILs constitute a promising class in which reliable, accurate vapor pressure measurements can in principle be performed. This property is paramount for assisting in the development and testing of accurate molecular models.

Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures

Science.gov (United States)

Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans

2009-02-01

For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.

Haze Formation and Behavior in Liquid-Liquid Extraction Processes

International Nuclear Information System (INIS)

Arm, Stuart T.; Jenkins, J. A.

2006-01-01

Aqueous haze formation and behavior was studied in the liquid-liquid system tri-n-butyl phosphate in odorless kerosene and 3M nitric acid with uranyl nitrate and cesium nitrate representing the major solute and an impurity, respectively. A pulsed column, mixer-settler and centrifugal contactor were chosen to investigate the effect of different turbulence characteristics on the manifestation of haze since these contactors exhibit distinct mixing phenomena. The dispersive processes of drop coalescence and breakage, and water precipitation in the organic phase were observed to lead to the formation of haze drops of ∼1 um in diameter. The interaction between the haze and primary drops of the dispersion was critical to the separation efficiency of the liquid-liquid extraction equipment. Conditions of high power input and spatially homogeneous mixing enabled the haze drops to become rapidly assimilated within the dispersion to maximize the scrub performance and separation efficiency of the equipment

A three-dimensional numerical study on dynamics behavior of a rising vapor bubble in uniformly superheated liquid by lattice Boltzmann method

International Nuclear Information System (INIS)

Sun, Tao; Sun, Jiangang; Ang, Xueye; Li, Shanshan; Su, Xin

2016-01-01

Highlights: • Dynamics of vapor bubble in uniformly superheated liquid is studied by a 3D LBM. • The growth rate reaches a maximum value and then decrease until a certain value. • The vapor bubble will take place a larger deformation at high ratio of Re/Eo. • The bubble wake has a great influence on motion and deformation of vapor bubble. • Ratio of Re/Eo has an important influence on evolution of temperature field. - Abstract: In this paper, dynamics behaviors of a rising vapor bubble in uniformly superheated liquid are firstly studied by a hybrid three-dimensional lattice Boltzmann model. In order to validate this model, two test cases regarding bubble rising in an isothermal system and vapor bubble growth in a superheated liquid are performed, respectively. The test results are consistent with existing results and indicate the feasibility of the hybrid model. The hybrid model is further applied to simulate growth and deformation of a rising vapor bubble in different physical conditions. Some physical parameters of vapor bubble such as equivalent diameter and growth rate are evaluated accurately by three-dimensional simulations. It is found that the growth rate of vapor bubble changes with time and temperature gradient. It reaches a maximum value at the initial stage and then decrease until a certain value. The growth and deformation of vapor bubble at different ratios of Re/Eo are discussed. The numerical results show the vapor bubble will take place a larger deformation at high ratio of Re/Eo at the middle and final stages. In addition, the hybrid model is also applied to predict the evolution of flow and temperature fields. The bubble wake has a great influence on the motion and deformation of vapor bubble during rising process. As far as the temperature field is concerned, a ratio of Re/Eo has an important influence on heat transfer and evolution of temperature field.

Effect of sludge behavior on performance of centrifugal contactor

Energy Technology Data Exchange (ETDEWEB)

Sakamoto, A.; Sano, Y.; Takeuchi, M. [Japan Atomic Energy Agency - JAEA, 4-33 Muramatsu Tokai-mura Naka-gun Ibaraki-pref. 319-1194 (Japan)

2016-07-01

The Japan Atomic Energy Agency has been developing an annular centrifugal contactor for solvent extraction in spent fuel reprocessing, which allows the mixing of aqueous and organic phases in the annular area and their separation from the mixed phase in the rotor. The effects of sludge behavior on the performance of a centrifugal contactor were investigated. Sludge accumulation during the operation of the centrifugal contactor was observed only in the rotor. Based on the sludge accumulation behavior, the effects of rotor sludge accumulation on the performance of phase separation and extraction were investigated using several types of rotors, which simulated different sludge accumulation levels in the separation area. It was confirmed that rotor sludge accumulation would affect the phase separation performance but not the extraction performance. This can be explained by the structure of the centrifugal contactor, wherein the extraction reaction and phase separation mainly proceed in the housing and rotor, respectively.

Mathematical prediction of freezing times of bovine semen in straws placed in static vapor over liquid nitrogen.

Science.gov (United States)

Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

2013-02-01

A widespread practice in cryopreservation is to freeze spermatozoa by suspending the straws in stagnant nitrogen vapor over liquid nitrogen (N(2)V/LN(2)) for variable periods of time before plunging into liquid nitrogen (-196°C) for indefinite storage. A mathematical heat transfer model was developed to predict freezing times (phase change was considered) required for bull semen and extender packaged in 0.5ml plastic straws and suspended in static liquid nitrogen vapor. Thermophysical properties (i.e. thermal conductivity, specific heat, density, initial freezing temperature) of bovine semen and extender as a function of temperature were determined considering the water change of phase. The non-stationary heat transfer partial differential equations with variable properties (nonlinear mathematical problem) were numerically solved considering in series thermal resistances (semen suspension-straw) and the temperature profiles were obtained for both semen suspension and plastic straw. It was observed both the external heat transfer coefficient in stagnant nitrogen vapor and its temperature (controlled by the distance from the surface of liquid nitrogen to the straw) affected freezing times. The accuracy of the model to estimate freezing times of the straws was further confirmed by comparing with experimental literature data. Results of this study will be useful to select "safe" holding times of bull semen in plastic straws placed N(2)V/LN(2) to ensure that complete freezing of the sample has occurred in the nitrogen vapor and avoid cryodamage when plunging in LN(2). Freezing times predicted by the numerical model can be applied to optimize freezing protocols of bull semen in straws. Copyright © 2012 Elsevier Inc. All rights reserved.

Wavelength dependence of liquid-vapor interfacial tension of Ga

International Nuclear Information System (INIS)

Li Dongxu; Yang Bin; Rice, Stuart A.; Lin Binhua; Meron, Mati; Gebhardt, Jeff; Graber, Tim

2004-01-01

The wave-vector dependence of the liquid-vapor interfacial tension of Ga, γ(q), has been determined from diffuse x-ray scattering measurements. The ratio γ(q)/γ(0)=1 for q -1 decreases to 0.5 near q=0.22 Angstrom -1 , and increases strongly for larger q. The observed form for γ(q)/γ(0) is consistent with the prediction from the Mecke-Dietrich theory when the known stratified liquid-vapor interfacial density profile of Ga and a pseudopotential based pair interaction with appropriate asymptotic (r→∞) behavior are used. The detailed behavior of γ(q)/γ(0) depends on the particular forms of both the interfacial density profile and the asymptotic falloff of the atomic pair interaction

Towards Cryogenic Liquid-Vapor Energy Storage Units for space applications

Science.gov (United States)

Afonso, Josiana Prado

With the development of mechanical coolers and very sensitive cryogenic sensors, it could be interesting to use Energy Storage Units (ESU) and turn off the cryocooler to operate in a free micro vibration environment. An ESU would also avoid cryogenic systems oversized to attenuate temperature fluctuations due to thermal load variations which is useful particularly for space applications. In both cases, the temperature drift must remain limited to keep good detector performances. In this thesis, ESUs based on the high latent heat associated to liquid-vapor phase change to store energy have been studied. To limit temperature drifts while keeping small size cell at low temperature, a potential solution consists in splitting the ESU in two volumes: a low temperature cell coupled to a cryocooler cold finger through a thermal heat switch and an expansion volume at room temperature to reduce the temperature increase occurring during liquid evaporation. To obtain a vanishing temperature drift, a new improvement has been tested using two-phase nitrogen: a controlled valve was inserted between the two volumes in order to control the cold cell pressure. In addition, a porous material was used inside the cell to turn the ESU gravity independent and suitable for space applications. In this case, experiments reveal not fully understood results concerning both energy storage and liquid-wall temperature difference. To capture the thermal influence of the porous media, a dedicated cell with poorly conductive lateral wall was built and operated with two-phase helium. After its characterization outside the saturation conditions (conduction, convection), experiments were performed, with and without porous media, heating at the top or the bottom of the cell with various heat fluxes and for different saturation temperatures. In parallel, a model describing the thermal response for a cell containing liquid and vapor with a porous medium heated at the top ("against gravity") was developed

Modeling interfacial area transport in multi-fluid systems

Energy Technology Data Exchange (ETDEWEB)

Yarbro, Stephen Lee [Univ. of California, Berkeley, CA (United States)

1996-11-01

Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacial area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.

Separation of gaseous air pollutants using membrane contactors

Science.gov (United States)

Sverak, T.; Bulejko, P.; Ostrezi, J.; Kristof, O.; Kalivoda, J.; Kejik, P.; Mayerova, K.; Adamcik, M.

2017-10-01

This work deals with the separation of CO2 gaseous pollutant from gas mixtures to a water solution using the laboratory contactor. The laboratory set process parameters showed the rate of carbon dioxide transition through the interface in a so promising level the contactor separators can be considered as a very promising pathway to reduce the content of this greenhouse gas from the air.

Integration issues of a plasma contactor Power Electronics Unit

Science.gov (United States)

Pinero, Luis R.; York, Kenneth W.; Bowers, Glen E.

1995-01-01

A hollow cathode-based plasma contactor is baselined on International Space Station Alpha (ISSA) for spacecraft charge control. The plasma contactor system consists of a hollow cathode assembly (HCA), a power electronics unit (PEU), and an expellant management unit (EMU). The plasma contactor has recently been required to operate in a cyclic mode to conserve xenon expellant and extend system life. Originally, a DC cathode heater converter was baselined for a continuous operation mode because only a few ignitions of the hollow cathode were expected. However, for cyclic operation, a DC heater supply can potentially result in hollow cathode heater component failure due to the DC electrostatic field. This can prevent the heater from attaining the proper cathode tip temperature for reliable ignition of the hollow cathode. To mitigate this problem, an AC cathode heater supply was therefore designed, fabricated, and installed into a modified PEU. The PEU was tested using resistive loads and then integrated with an engineering model hollow cathode to demonstrate stable steady-state operation. Integration issues such as the effect of line and load impedance on the output of the AC cathode heater supply and the characterization of the temperature profile of the heater under AC excitation were investigated.

Thermal-hydraulic behaviors of vapor-liquid interface due to arrival of a pressure wave

Energy Technology Data Exchange (ETDEWEB)

Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo [Tokyo Institute of Technology (Japan)

1995-09-01

In the vapor explosion, a pressure wave (shock wave) plays a fundamental role for triggering, propagation and enhancement of the explosion. Energy of the explosion is related to the magnitude of heat transfer rate from hot liquid to cold volatile one. This is related to an increasing rate of interface area and to an amount of transient heat flux between the liquids. In this study, the characteristics of transient heat transfer and behaviors of vapor film both on the platinum tube and on the hot melt tin drop, under same boundary conditions have been investigated. It is considered that there exists a fundamental mechanism of the explosion in the initial expansion process of the hot liquid drop immediately after arrival of pressure wave. The growth rate of the vapor film is much faster on the hot liquid than that on the solid surface. Two kinds of roughness were observed, one due to the Taylor instability, by rapid growth of the explosion bubble, and another, nucleation sites were observed at the vapor-liquid interface. Based on detailed observation of early stage interface behaviors after arrival of a pressure wave, the thermal fragmentation mechanism is proposed.

Modeling vapor-liquid interfaces with the gradient theory in combination with the CPA equation of state

DEFF Research Database (Denmark)

Queimada, Antonio; Miqueu, C; Marrucho, IM

2005-01-01

and the correct phase equilibrium of water + hydrocarbon systems already obtained from CPA. In this work, preliminary studies involving the vapor-liquid interfacial tensions of some selected associating and non-associating pure components (water, ethanol, n-butane, n-pentane, n-hexane, n-heptane) are presented...

Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

Science.gov (United States)

Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

2007-09-07

The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

Hybrid indirect/direct contactor for thermal management of counter-current processes

Science.gov (United States)

Hornbostel, Marc D.; Krishnan, Gopala N.; Sanjurjo, Angel

2018-03-20

The invention relates to contactors suitable for use, for example, in manufacturing and chemical refinement processes. In an aspect is a hybrid indirect/direct contactor for thermal management of counter-current processes, the contactor comprising a vertical reactor column, an array of interconnected heat transfer tubes within the reactor column, and a plurality of stream path diverters, wherein the tubes and diverters are configured to block all straight-line paths from the top to bottom ends of the reactor column.

Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

Science.gov (United States)

Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

2010-04-14

Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.

Membrane contactors for CO2 capture processes - critical review

Science.gov (United States)

Nogalska, Adrianna; Trojanowska, Anna; Garcia-Valls, Ricard

2017-07-01

The use of membrane contactor in industrial processes is wide, and lately it started to be used in CO2 capture process mainly for gas purification or to reduce the emission. Use of the membrane contactor provides high contact surface area so the size of the absorber unit significantly decreases, which is an important factor for commercialization. The research has been caried out regarding the use of novel materials for the membrane production and absorbent solution improvements. The present review reveals the progress in membrane contactor systems for CO2 capture processes concerning solution for ceramic membrane wetting, comparison study of different polymers used for fabrication and methods of enzyme immobilization for biocomposite membrane. Also information about variety of absorbent solutions is described.

A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

International Nuclear Information System (INIS)

Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

2009-01-01

In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm 3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

Science.gov (United States)

Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

2009-06-01

In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

Isobaric (vapor + liquid) equilibria of 1-ethyl-3-methylimidazolium ethylsulfate plus (propionaldehyde or valeraldehyde): Experimental data and prediction

International Nuclear Information System (INIS)

Alvarez, Victor H.; Mattedi, Silvana; Aznar, Martin

2011-01-01

Research highlights: → We report density, refraction index, and VLE for (propionaldehyde or valeraldehyde) + [emim][EtSO 4 ]. → The Peng -Robinson + Wong -Sandler + COSMO-SAC model was used to predict density and VLE. → The densities were predicted with deviations below than 2.3%. → The experimental VLE was predicted with deviations below than 1.6%. - Abstract: This paper reports the density, refraction index, and (vapor + liquid) equilibria (VLE) for binary systems {aldehyde + 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO 4 ])}: {propionaldehyde + [emim][EtSO 4 ]} and {valeraldehyde + [emim][EtSO 4 ]}. The uncertainties for the temperature, pressure, and compositions measurements for the phase equilibria are ±0.1 K, ±0.01 kPa and ±0.0004, respectively. A qualitative analysis of the variation of the properties with changes in solvent and temperature was performed. The Peng-Robinson equation of state (PR EoS), coupled with the Wong-Sandler mixing rule (WS), is used to describe the experimental data. To calculate activity coefficients we used three different models: NRTL, UNIQUAC, and COSMO-SAC. Since the predictive liquid activity coefficient model COSMO-SAC is used in the Wong-Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the (vapor + liquid) equilibria have a deviation lower than 2.3% and 1.6%, respectively. The (vapor + liquid) equilibria predictions show a good description for the propionaldehyde system and only a qualitative description for the valeraldehyde system.

Molecular interpretation of Trouton's and Hildebrand's rules for the entropy of vaporization of a liquid

International Nuclear Information System (INIS)

Green, James A.; Irudayam, Sheeba Jem; Henchman, Richard H.

2011-01-01

Research highlights: → A method to calculate a liquid's entropy of vaporization is proposed. → The entropy of vaporisation depends on force magnitudes from computer simulation. → Calculated values agree with experiment, Trouton's rule and Hildebrand's rule. → Free volumes decrease for larger molecules or those with stronger interactions. - Abstract: The entropy of vaporization at a liquid's boiling point is well approximated by Trouton's rule and even more accurately by Hildebrand's rule. A cell method is used here to calculate the entropy of vaporization for a range of liquids by subtracting the entropy of the gas from that of the liquid. The liquid's entropy is calculated from the force magnitudes measured in a molecular dynamics simulation based on the harmonic approximation. The change in rotational entropy is not accounted for except in the case of liquid water. The predicted entropies of vaporization agree well with experiment and Trouton's and Hildebrand's rules for most liquids and for water except other liquids with hydrogen bonds. This supports the idea that molecular rotation is close to ideal at a liquid's boiling point if hydrogen bonds are absent; if they are present, then the rotational entropy gain must be included. The method provides a molecular interpretation of those rules by providing an equation in terms of a molecule's free volume in a liquid which depends on the force magnitudes. Free volumes at each liquid's boiling point are calculated to be ∼1 A 3 for liquids lacking hydrogen bonds, lower at ∼0.3 A 3 for those with hydrogen bonds, and they decrease weakly with increasing molecular size.

Liquid-vapor phase transition upon pressure decrease in the lead-bismuth system

Science.gov (United States)

Volodin, V. N.

2009-11-01

The liquid-vapor phase transitions boundaries were calculated on the basis of the values of vapor pressure of the components in the lead-bismuth system during the stepwise pressure decrease by one order of magnitude from 105 down to 1 Pa. The emergence of azeotropic liquid under pressure lower than 19.3 kPa was ascertained. The emergence of azeotropic mixture near the lead edge of the phase diagram was concluded to be the reason for technological difficulties in the distillation separation of the system into the components in a vacuum.

Semiempirical self-consistent polarization description of bulk water, the liquid-vapor interface, and cubic ice.

Science.gov (United States)

Murdachaew, Garold; Mundy, Christopher J; Schenter, Gregory K; Laino, Teodoro; Hutter, Jürg

2011-06-16

We have applied an efficient electronic structure approach, the semiempirical self-consistent polarization neglect of diatomic differential overlap (SCP-NDDO) method, previously parametrized to reproduce properties of water clusters by Chang, Schenter, and Garrett [ J. Chem. Phys. 2008 , 128 , 164111 ] and now implemented in the CP2K package, to model ambient liquid water at 300 K (both the bulk and the liquid-vapor interface) and cubic ice at 15 and 250 K. The SCP-NDDO potential retains its transferability and good performance across the full range of conditions encountered in the clusters and the bulk phases of water. In particular, we obtain good results for the density, radial distribution functions, enthalpy of vaporization, self-diffusion coefficient, molecular dipole moment distribution, and hydrogen bond populations, in comparison to experimental measurements. © 2011 American Chemical Society

X-Ray Scattering Studies of the Liquid-Vapor Interface of Gallium.

Science.gov (United States)

Kawamoto, Eric Hitoshi

A UHV system was developed for performing X-ray scattering studies and in situ analyses of liquid metal surfaces. A nearly ideal choice for this study, gallium has a melting point just above room temperature; is amenable to handling in both air and vacuum; its surface oxides can be removed while its cleanliness is maintained and monitored. Using argon glow-discharge sputtering techniques to remove intervening surface oxides, thin wetting layers of gallium were prepared atop nonreactive substrates, to be used as samples suited for liquid surface scattering experiments. Preliminary measurements of X-ray reflectivity from the liquid-vapor interface of gallium were performed with the X-ray UHV chamber configured for use in conjunction with liquid surface spectrometers at two synchrotron beamlines. A novel technique for carrying out and interpreting scattering measurements from curved liquid surfaces was demonstrated. The energy tunability and intense focused white beam flux from a wiggler source was shown to place within reach the large values of wavevector transfer at which specular reflectivity data yield small length scale information about surface structure. Various theoretical treatments and simulations predict quasi-lamellar ordering of atoms near the free surface of metallic liquids due to energetics particular to metals (electron delocalization, the dependence of system energy on ion and electron densities, surface tension and electrostatic energy). However, the experimental data reported to date is insufficient to distinguish between a monotonic, sigmoidal electron density profile found at the free surfaces of dielectric liquids, and the damped oscillatory layer-like profiles anticipated for metallic liquids. Out to a wavevector transfer of Q = 0.55 A ^{-1}, the reflectivity data measured from a curved Ga surface is not inconsistent with what is expected for a liquid-vapor electron density profile of Gaussian width sigma = 1.3 +/- 0.2 A. Subsequent

Improved annular centrifugal contactor for solvent extraction reprocessing of nuclear reactor fuel

International Nuclear Information System (INIS)

Bernstein, G.J.; Leonard, R.A.; Ziegler, A.A.; Steindler, M.J.

1978-01-01

An improved annular centrifugal contactor has been developed for solvent extraction reprocessing of spent nuclear reactor fuel. The design is an extension of a contactor developed several years ago at Argonne National Laboratory. Its distinguishing features are high throughput, high stage efficiency and the ability to handle a broad range of aqueous-to-organic phase flow ratios and density ratios. Direct coupling of the mixing and separating rotor to a motorized spindle simplifies the design and makes the contactor particularly suitable for remote maintenance. A unit that is critically safe by geometry is under test and a larger unit is being fabricated. Multi-stage miniature contactors operating on the annular mixing principle are being used for laboratory flow sheet studies. 8 figures

Modeling of vapor-liquid-liquid equilibria in binary mixtures

NARCIS (Netherlands)

Tzabar, Nir; ter Brake, Hermanus J.M.

2016-01-01

Vapor compression and Joule–Thomson (JT) cycles provide cooling power at the boiling temperatures of the refrigerants. Maintaining a fixed pressure in the evaporator allows for a stable cooling temperature at the boiling point of a pure refrigerant. In these coolers enhanced cooling power can be

Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {1,1,1,2-tetrafluoroethane (R134a) + propane (R290)} by a recirculation apparatus with view windows

International Nuclear Information System (INIS)

Dong Xueqiang; Gong Maoqiong; Liu Junsheng; Wu Jianfeng

2011-01-01

The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than ±5 mK, ±0.0005 MPa, and ±0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

Science.gov (United States)

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems

Energy Technology Data Exchange (ETDEWEB)

Mun, S Y; Lee, H

1999-12-01

Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated. For the analysis of salt-containing solutions, a method incorporating refractometry and gravimetry was used. From the experimental measurements, the effect of lithium bromide on the VLE behavior of water + 1,3-propanediol was investigated. The experimental data of the salt-free system were successfully correlated using the Wilson, NRTL, and UNIQUAC models. In addition, the extended UNIQUAC model of Sander et al. was applied to the VLE calculation of salt-containing mixtures.

Multicomponent droplet vaporization in a convecting environment

International Nuclear Information System (INIS)

Megaridis, C.M.; Sirignano, W.A.

1990-01-01

In this paper a parametric study of the fundamental exchange processes for energy, mass and momentum between the liquid and gas phases of multicomponent liquid vaporizing droplets is presented. The model, which examines an isolated, vaporizing, multicomponent droplet in an axisymmetric, convecting environment, considers the different volatilities of the liquid components, the alteration of the liquid-phase properties due to the spatial/temporal variations of the species concentrations and also the effects of multicomponent diffusion. In addition, the model accounts for variable thermophysical properties, surface blowing and droplet surface regression due to vaporization, transient droplet heating with internal liquid circulation, and finally droplet deceleration with respect to the free flow due to drag. The numerical calculation employs finite-difference techniques and an iterative solution procedure that provides time-varying spatially-resolved data for both phases. The effects of initial droplet composition, ambient temperature, initial Reynolds number (based on droplet diameter), and volatility differential between the two liquid components are investigated for a liquid droplet consisting of two components with very different volatilities. It is found that mixtures with higher concentration of the less volatile substance actually vaporize faster on account of intrinsically higher liquid heating rates

Measurements of the vapor-liquid coexistence curve and the critical parameters for 1,1,1,2-tetrafluoroethane

Science.gov (United States)

Kabata, Y.; Tanikawa, S.; Uematsu, M.; Watanabe, K.

1989-05-01

Measurements of the vapor-liquid coexistence curve in the critical region for 1,1,1,2-tetrafluoroethane (R134a; CH2FCF3), which is currently considered as a prospective substitute for conventional refrigerant R12, have been performed by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-seven saturated densities along the vapor-liquid coexistence curve between 208 and 999 kg·m-3 have been obtained in the temperature range 343 K to the critical temperature. The experimental uncertainties in temperature and density measurements have been estimated to be within ±10mK and ±0.55%, respectively. On the basis of these measurements near the critical point, the critical temperature and the critical density for 1,1,1,2-tetrafluoroethane were determined in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence. In addition, the critical exponent ß along the vapor-liquid coexistence curve has been determined in accord with the difference between the density of the saturated liquid and that of the saturated vapor.

Engineering test of stripping performance by multi-centrifugal contactors system for spent nuclear reprocessing

International Nuclear Information System (INIS)

Masayuki Takeuchi; Tadahiro Washiya; Hiroki Nakabayashi; Takashi Suganuma; Shinnichi Aose

2005-01-01

Japan Nuclear Cycle Development Institute (JNC) has been developing centrifugal contactors which are compact and high performance for solvent extraction process in industrial reprocessing plant. The stripping performance including equilibrium time for distribution and hydraulic behavior of the multi-centrifugal contactors were mainly evaluated by using uranium nitrite solution on engineering scale (10 kgHM/hr). In particular, the effects of feed temperature of stripping solution and O/A on the stripping performance were focused in this test. As results, no hydraulic problem such as overflow and entrainment were observed in multi-centrifugal contactors system through all conditions, and the uranium and acid concentrations showed desirable profiles which were nearly consistent with calculated one by MIXSET-X code. As to stripping performance, uranium leak concentration in solvent reached to less than 0.01 g/L, which is target of the stripping performance on this centrifugal contactors system, within nine stages on all conditions. It was also found that the effect of feed temperature of stripping solution (35 degree C → 60 degree C) or O/A (1.0→0.8) on stripping performance corresponds to distribution capacity of two contactors, respectively. The stage efficiency for a contactor was estimated as 97-98% on stripping stage. There were no uranium leaks (less than 40μg/L) in spent solvent discharged from the final stage. The profiles of uranium concentration in multi-contactors become stable within 10 minutes after the stripping test starting. In this way, it was demonstrated that the centrifugal contactors system has good stripping performance on engineering scale. (authors)

Incorporating Phase-Dependent Polarizability in Non-Additive Electrostatic Models for Molecular Dynamics Simulations of the Aqueous Liquid-Vapor Interface.

Science.gov (United States)

Bauer, Brad A; Warren, G Lee; Patel, Sandeep

2009-02-10

We discuss a new classical water force field that explicitly accounts for differences in polarizability between liquid and vapor phases. The TIP4P-QDP (4-point transferable intermolecular potential with charge dependent-polarizability) force field is a modification of the original TIP4P-FQ fluctuating charge water force field of Rick et al.(1) that self-consistently adjusts its atomic hardness parameters via a scaling function dependent on the M-site charge. The electronegativity (χ) parameters are also scaled in order to reproduce condensed-phase dipole moments of comparable magnitude to TIP4P-FQ. TIP4P-QDP is parameterized to reproduce experimental gas-phase and select condensed-phase properties. The TIP4P-QDP water model possesses a gas phase polarizability of 1.40 Å(3) and gas-phase dipole moment of 1.85 Debye, in excellent agreement with experiment and high-level ab initio predictions. The liquid density of TIP4P-QDP is 0.9954(±0.0002) g/cm(3) at 298 K and 1 atmosphere, and the enthalpy of vaporization is 10.55(±0.12) kcal/mol. Other condensed-phase properties such as the isobaric heat capacity, isothermal compressibility, and diffusion constant are also calculated within reasonable accuracy of experiment and consistent with predictions of other current state-of-the-art water force fields. The average molecular dipole moment of TIP4P-QDP in the condensed phase is 2.641(±0.001) Debye, approximately 0.02 Debye higher than TIP4P-FQ and within the range of values currently surmised for the bulk liquid. The dielectric constant, ε = 85.8 ± 1.0, is 10% higher than experiment. This is reasoned to be due to the increase in the condensed phase dipole moment over TIP4P-FQ, which estimates ε remarkably well. Radial distribution functions for TIP4P-QDP and TIP4P-FQ show similar features, with TIP4P-QDP showing slightly reduced peak heights and subtle shifts towards larger distance interactions. Since the greatest effects of the phase-dependent polarizability are

Incorporating Phase-Dependent Polarizability in Non-Additive Electrostatic Models for Molecular Dynamics Simulations of the Aqueous Liquid-Vapor Interface

Science.gov (United States)

Bauer, Brad A.; Warren, G. Lee; Patel, Sandeep

2012-01-01

We discuss a new classical water force field that explicitly accounts for differences in polarizability between liquid and vapor phases. The TIP4P-QDP (4-point transferable intermolecular potential with charge dependent-polarizability) force field is a modification of the original TIP4P-FQ fluctuating charge water force field of Rick et al.1 that self-consistently adjusts its atomic hardness parameters via a scaling function dependent on the M-site charge. The electronegativity (χ) parameters are also scaled in order to reproduce condensed-phase dipole moments of comparable magnitude to TIP4P-FQ. TIP4P-QDP is parameterized to reproduce experimental gas-phase and select condensed-phase properties. The TIP4P-QDP water model possesses a gas phase polarizability of 1.40 Å3 and gas-phase dipole moment of 1.85 Debye, in excellent agreement with experiment and high-level ab initio predictions. The liquid density of TIP4P-QDP is 0.9954(±0.0002) g/cm3 at 298 K and 1 atmosphere, and the enthalpy of vaporization is 10.55(±0.12) kcal/mol. Other condensed-phase properties such as the isobaric heat capacity, isothermal compressibility, and diffusion constant are also calculated within reasonable accuracy of experiment and consistent with predictions of other current state-of-the-art water force fields. The average molecular dipole moment of TIP4P-QDP in the condensed phase is 2.641(±0.001) Debye, approximately 0.02 Debye higher than TIP4P-FQ and within the range of values currently surmised for the bulk liquid. The dielectric constant, ε = 85.8 ± 1.0, is 10% higher than experiment. This is reasoned to be due to the increase in the condensed phase dipole moment over TIP4P-FQ, which estimates ε remarkably well. Radial distribution functions for TIP4P-QDP and TIP4P-FQ show similar features, with TIP4P-QDP showing slightly reduced peak heights and subtle shifts towards larger distance interactions. Since the greatest effects of the phase-dependent polarizability are

Structure of the liquid-vapor interface of a dilute ternary alloy: Pb and In in Ga

International Nuclear Information System (INIS)

Yang Bin; Li Dongxu; Rice, Stuart A.

2003-01-01

We report the results of experimental studies of how the competition between two solutes to segregate in the liquid-vapor interface of a dilute ternary alloy influences the composition and structure of that interface. The system studied has small amounts of Pb and In dissolved in Ga; it differs from a previous study of dilute alloys containing small amounts of Pb and Sn dissolved in Ga by the addition of a new variable, namely, the valence difference between the solute atoms Pb and In. This valence difference influences the electron density distribution in the alloy liquid-vapor interface in proportion to the excess concentrations of the solute species in the interface, and thereby should affect the structure of the interface. We find that for a ternary PbInGa alloy that contains 0.039 at. % Pb and 6.31 at. % In, the Pb that segregates in the liquid-vapor interface forms a two-dimensional hexagonal crystal phase that undergoes a first-order transition to a disordered phase at T=29.0±0.1 deg. C. The two-dimensional crystalline Pb forms about 0.6 of a full monolayer; the remainder of the outer stratum of the liquid-vapor interface is filled with two-dimensional liquid In. For a ternary PbInGa alloy that contains the same amount of Pb and 12.2 at. % In, the Pb that segregates in the liquid-vapor interface forms a two-dimensional liquid down to 26.0 deg. C, the lowest temperature at which data were taken. For temperatures in excess of 29.0 deg. C two-dimensional liquid Pb and two-dimensional liquid In coexist in the interface, with the fractional occupation of the monolayer by In exceeding the fractional occupation by Pb

A Centrifugal Contactor Design to Facilitate Remote Replacement

International Nuclear Information System (INIS)

Meikrantz, David H.; Law, Jack D.; Garn, Troy G.; Macaluso, Lawrence L.

2011-01-01

Advanced designs of nuclear fuel recycling and radioactive waste treatment plants are expected to include more ambitious goals for solvent extraction based separations including; higher separations efficiency, high-level waste minimization, and a greater focus on continuous processes to minimize cost and footprint. Therefore, Annular Centrifugal Contactors (ACCs) are destined to play a more important role for such future processing schemes. This work continues the development of remote designs for ACCs that can process the large throughputs needed for future nuclear fuel recycling and radioactive waste treatment plants. A three stage, 12.5 cm diameter rotor module has been constructed and is being evaluated for use in highly radioactive environments. This prototype assembly employs three standard CINC V-05 clean-in-place (CIP) units modified for remote service and replacement via new methods of connection for solution inlets, outlets, drain and CIP. Hydraulic testing and functional checks were successfully conducted and then the prototype was evaluated for remote handling and maintenance. Removal and replacement of the center position V-05R contactor in the three stage assembly was demonstrated using an overhead rail mounted PaR manipulator. Initial evaluation indicates a viable new design for interconnecting and cleaning individual stages while retaining the benefits of commercially reliable ACC equipment. Replacement of a single stage via remote manipulators and tools is estimated to take about 30 minutes, perhaps fast enough to support a contactor change without loss of process equilibrium. The design presented in this work is scalable to commercial ACC models from V-05 to V-20 with total throughput rates ranging from 20 to 650 liters per minute.

Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

Science.gov (United States)

Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

2013-01-01

Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

Development of analytical model for condensation of vapor mixture of nitric acid and water affected volatilized ruthenium behavior in accident of evaporation to dryness by boiling of reprocessed high level liquid waste at fuel reprocessing facilities

International Nuclear Information System (INIS)

Yoshida, Kazuo

2016-08-01

An accident of evaporation to dryness by boiling of high level liquid waste is postulated as one of the severe accidents caused by the loss of cooling function at a fuel reprocessing plant. In this case, continuous vaporing of nitric acid and water leads to increase Ru volatilization in liquid waste temperature over 120degC at later boiling and dry out phases. It has been observed at the experiments with actual and synthetic liquid waste that some amount of Ru volatilizes and transfers into condensed nitric acid solution at those phases. The nitric acid and water vapor flowing from waste tank are expected to condense at compartments of actual facilities building. The volatilized Ru could transfer into condensed liquid. It is key issues for quantifying the amount of transferred Ru through the facility building to simulate these thermodynamic and chemical behaviors. An analytical model has been proposed in this report based on the condensation mechanisms of nitric acid and water in vapor-liquid equilibria. It has been also carried out for the proposed model being feasible to formulate the activity coefficients and to review the thermodynamic properties of nitric acid solution. Practicability of the proposed analytical model has been shown successfully through the feasibility study with simulation of an experiment result. (author)

A corresponding states treatment of the liquid-vapor saturation line

International Nuclear Information System (INIS)

Srinivasan, K.; Ng, K.C.; Velasco, S.; White, J.A.

2012-01-01

Highlights: → Correlations arising from the maxima of products of properties in the coexistence line. → Analysis of maxima along the vapor pressure curve. → Correlations for the maximum of the saturated vapor enthalpy curve. → Prediction of properties of the new low GWP refrigerants HFO 1234yf and HFO 1234ze (E). - Abstract: In this work we analyze correlations for the maxima of products of some liquid-vapor saturation properties. These points define new characteristic properties of each fluid that are shown to exhibit linear correlations with the critical properties. We also demonstrate that some of these properties are well correlated with the acentric factor. An application is made to predict the properties of two new low global warming potential (GWP) refrigerants.

IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

Energy Technology Data Exchange (ETDEWEB)

Ni, Yicun; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

2015-07-07

Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm{sup −1} and a positive band centered at 1670 cm{sup −1}. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

Science.gov (United States)

Ni, Yicun; Skinner, J. L.

2015-07-01

Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm-1 and a positive band centered at 1670 cm-1. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

Vapor phase versus liquid phase grafting of meso-porous alumina

NARCIS (Netherlands)

Sripathi, V.G.P.; Mojet, Barbara; Nijmeijer, Arian; Benes, Nieck Edwin

2013-01-01

Functionalization of meso-porous c-alumina has been performed by grafting of 3-Aminopropyltrimethoxysilane (3APTMS) simultaneously from either the liquid phase or from the vapor phase. In both cases, after grafting nitrogen physisorption indicates that the materials remain meso-porous with

Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {l_brace}1,1,1,2-tetrafluoroethane (R134a) + propane (R290){r_brace} by a recirculation apparatus with view windows

Energy Technology Data Exchange (ETDEWEB)

Dong Xueqiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gong Maoqiong, E-mail: gongmq@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Liu Junsheng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Wu Jianfeng, E-mail: jfwu@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China)

2011-03-15

The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than {+-}5 mK, {+-}0.0005 MPa, and {+-}0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

Tests of a Higgins contactor for the engineering-scale resin loading of uranium

International Nuclear Information System (INIS)

Spence, R.D.; Haas, P.A.

1978-01-01

The loading of uranium on weak-acid ion exchange resin is a basic step in the production of fuel particles for high-temperature gas-cooled reactors (HTGRs). In the work reported here, an engineering-scale continuous resin loader (2-in.-ID Higgins contactor) was tested with existing engineering-scale process equipment. The Higgins contactor was first successfully used to convert Na + -form resin to the H + -form; then it was evaluated as a uranium loader. Results show that the 2-in.-ID Higgins contactor can easily load 25 kg of uranium per day, indicating that a 4-in.-ID contactor could load 100 kg/day. Process control was achieved by monitoring and controlling the density, pH, and inventory volume of the uranium feed solution. This control scheme is amenable to remote operation

ISS and Space Environment Interactions in Event of Plasma Contactor Failure

Science.gov (United States)

Carruth, M. R., Jr.; Munafo, Paul M. (Technical Monitor)

2000-01-01

The International Space Station (ISS), illustrated in Figure 1, will be the largest, highest power spacecraft placed in orbit. Because of this the design of the electrical power system diverged markedly from previous systems. The solar arrays will operate at 160 V and the power distribution voltage will be 120 V. The structure is grounded to the negative side of the solar arrays so under the right circumstances it is possible to drive the ISS potential very negative. A plasma contactor has been added to the ISS to provide control of the ISS structure potential relative to the ambient plasma. The ISS requirement is that the ISS structure not be greater than 40 V positive or negative of local plasma. What are the ramifications of operating large structures with such high voltage power systems? The application of a plasma contactor on ISS controls the potential between the structure and the local plasma, preventing degrading effects. It is conceivable that there can be situations where the plasma contactor might be non-functional. This might be due to lack of power, the need to turn it off during some of the build-up sequences, the loss of functionality for both plasma contactors before a replacement can be installed, and similar circumstances. A study was undertaken to understand how important it is to have the contactor functioning and how long it might be off before unacceptable degradation to ISS could occur.

Hybrid Multiphase CFD Solver for Coupled Dispersed/Segregated Flows in Liquid-Liquid Extraction

Directory of Open Access Journals (Sweden)

Kent E. Wardle

2013-01-01

Full Text Available The flows in stage-wise liquid-liquid extraction devices include both phase segregated and dispersed flow regimes. As a additional layer of complexity, for extraction equipment such as the annular centrifugal contactor, free-surface flows also play a critical role in both the mixing and separation regions of the device and cannot be neglected. Traditionally, computional fluid dynamics (CFD of multiphase systems is regime dependent—different methods are used for segregated and dispersed flows. A hybrid multiphase method based on the combination of an Eulerian multifluid solution framework (per-phase momentum equations and sharp interface capturing using Volume of Fluid (VOF on selected phase pairs has been developed using the open-source CFD toolkit OpenFOAM. Demonstration of the solver capability is presented through various examples relevant to liquid-liquid extraction device flows including three-phase, liquid-liquid-air simulations in which a sharp interface is maintained between each liquid and air, but dispersed phase modeling is used for the liquid-liquid interactions.

Vapor pressure determination of liquid UO/sub 2/ using a boiling point technique

International Nuclear Information System (INIS)

Bober, M.; Singer, J.

1987-01-01

By analogy with the classic boiling point method, a quasi-stationary millisecond laser-heating technique was applied to measure the saturated vapor pressure curve of liquid UO/sub 2/ in the temperature range of 3500 to 4500 K. The results are represented by log rho (MPa)=5.049 - 23 042/T (K), which gives an average heat of vaporization of 441 kJ/mol and a normal boiling point of 3808 K. In addition, spectral emissivities of liquid UO/sub 2/ were determined as a function of the temperature at the pyrometer wavelengths of 752 and 1064 nm

Validation of a simple method for predicting the disinfection performance in a flow-through contactor.

Science.gov (United States)

Pfeiffer, Valentin; Barbeau, Benoit

2014-02-01

Despite its shortcomings, the T10 method introduced by the United States Environmental Protection Agency (USEPA) in 1989 is currently the method most frequently used in North America to calculate disinfection performance. Other methods (e.g., the Integrated Disinfection Design Framework, IDDF) have been advanced as replacements, and more recently, the USEPA suggested the Extended T10 and Extended CSTR (Continuous Stirred-Tank Reactor) methods to improve the inactivation calculations within ozone contactors. To develop a method that fully considers the hydraulic behavior of the contactor, two models (Plug Flow with Dispersion and N-CSTR) were successfully fitted with five tracer tests results derived from four Water Treatment Plants and a pilot-scale contactor. A new method based on the N-CSTR model was defined as the Partially Segregated (Pseg) method. The predictions from all the methods mentioned were compared under conditions of poor and good hydraulic performance, low and high disinfectant decay, and different levels of inactivation. These methods were also compared with experimental results from a chlorine pilot-scale contactor used for Escherichia coli inactivation. The T10 and Extended T10 methods led to large over- and under-estimations. The Segregated Flow Analysis (used in the IDDF) also considerably overestimated the inactivation under high disinfectant decay. Only the Extended CSTR and Pseg methods produced realistic and conservative predictions in all cases. Finally, a simple implementation procedure of the Pseg method was suggested for calculation of disinfection performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Liquids - vapor and liquids - solids equilibria in the system Th(NO3)4 - UO2(NO3)2 - HNO3 - H2O

International Nuclear Information System (INIS)

Volk, V.I.; Vakhrushin, A.Yu.; Mamaev, S.L.; Zhirnov, Yu.P.

1999-01-01

Liquids - vapor and liquids - solids equilibria in the system Th(NO 3 ) 4 - UO 2 (NO 3 ) 2 - HNO 3 - H 2 O were investigated. It was established that in this system thorium nitrate hexahydrate and uranyl nitrate hexa- and trihydrate are formed. Empiric equations of solubility isotherm at 25 deg C were found. Densities of liquid phases of the system were determined. It was established that uranyl nitrates and thorium nitrates salt out nitric acid in vapor phase just as separately so in the case of mutual presence. Empiric equation fixing relationship between nitric acid concentration in condensed phase and concentrations of all components in liquid phase was found

3D printed modular centrifugal contactors and method for separating moieties using 3D printed optimized surfaces

Science.gov (United States)

Wardle, Kent E.

2017-08-29

The present invention provides an annular centrifugal contactor, having a housing to receive a plurality of liquids; a rotor inside the housing; an annular mixing zone, with a plurality of fluid retention reservoirs; and an adjustable stem that can be raised to restrict the flow of a liquid into the rotor or lowered to increase the flow of liquid into the rotor. The invention also provides a method for transferring moieties from a first liquid to a second liquid, the method having the steps of combining the fluids in a housing whose interior has helically shaped first channels; subjecting the fluids to a spinning rotor to produce a mixture, whereby the channels simultaneously conduct the mixture downwardly and upwardly; and passing the mixture through the rotor to contact second channels, whereby the channels pump the second liquid through a first aperture while the first fluid exits a second aperture.

Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

Science.gov (United States)

Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

2008-01-01

Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

Thermodynamic modeling of liquid–liquid phase change solvents for CO2 capture

DEFF Research Database (Denmark)

Waseem Arshad, Muhammad; von Solms, Nicolas; Thomsen, Kaj

2016-01-01

A thermodynamic model based on Extended UNIQUAC framework has been developed in this work for the de-mixing liquid–liquid phase change solvents, DEEA (2-(diethylamino)ethanol) and MAPA (3-(methylamino)propylamine). Parameter estimation was performed for two ternary systems, H2O-DEEA-CO2 and H2O......-MAPA-CO2, and a quaternary system, H2O-DEEA-MAPA-CO2 (phase change system), by using different types of experimental data (equilibrium and thermal) consisting of pure amine vapor pressure, vapor-liquid equilibrium, solid-liquid equilibrium, liquid–liquid equilibrium, excess enthalpy, and heat of absorption...

CFD modeling of condensation process of water vapor in supersonic flows

DEFF Research Database (Denmark)

Yang, Yan; Walther, Jens Honore; Yan, Yuying

2017-01-01

The condensation phenomenon of vapor plays an important role in various industries, such as the steam flow in turbines and refrigeration system. A mathematical model is developed to predict the spontaneous condensing phenomenon in the supersonic flows using the nucleation and droplet growth...... theories. The numerical approach is validated with the experimental data, which shows a good agreement between them. The condensation characteristics of water vapor in the Laval nozzle are described in detail. The results show that the condensation process is a rapid variation of the vapor-liquid phase...... change both in the space and in time. The spontaneous condensation of water vapor will not appear immediately when the steam reaches the saturation state. Instead, it occurs further downstream the nozzle throat, where the steam is in the state of supersaturation....

Understanding the vapor-liquid-solid growth and composition of ternary III-V nanowires and nanowire heterostructures

Science.gov (United States)

Dubrovskii, V. G.

2017-11-01

Based on the recent achievements in vapor-liquid-solid (VLS) synthesis, characterization and modeling of ternary III-V nanowires and axial heterostructures within such nanowires, we try to understand the major trends in their compositional evolution from a general theoretical perspective. Clearly, the VLS growth of ternary materials is much more complex than in standard vapor-solid epitaxy techniques, and even maintaining the necessary control over the composition of steady-state ternary nanowires is far from straightforward. On the other hand, VLS nanowires offer otherwise unattainable material combinations without introducing structural defects and hence are very promising for next-generation optoelectronic devices, in particular those integrated with a silicon electronic platform. In this review, we consider two main problems. First, we show how and by means of which parameters the steady-state composition of Au-catalyzed or self-catalyzed ternary III-V nanowires can be tuned to a desired value and why it is generally different from the vapor composition. Second, we present some experimental data and modeling results for the interfacial abruptness across axial nanowire heterostructures, both in Au-catalyzed and self-catalyzed VLS growth methods. Refined modeling allows us to formulate some general growth recipes for suppressing the unwanted reservoir effect in the droplet and sharpening the nanowire heterojunctions. We consider and refine two approaches developed to date, namely the regular crystallization model for a liquid alloy with a critical size of only one III-V pair at high supersaturations or classical binary nucleation theory with a macroscopic critical nucleus at modest supersaturations.

Assessment of bacterial growth and total organic carbon removal on granular activated carbon contactors.

Science.gov (United States)

Bancroft, K; Maloney, S W; McElhaney, J; Suffet, I H; Pipes, W O

1983-01-01

The overall growth rate of bacteria on granular activated carbon (GAC) contactors at the Philadelphia Torresdale Water Treatment Pilot Plant facility was found to decrease until steady state was reached. The growth rate was found to fluctuate between 6.94 X 10(-3) and 8.68 X 10(-4) doublings per h. The microbiological removal of total organic carbon (TOC) was calculated by considering the GAC contactors as semiclosed continuous culture systems and using growth yield factors determined in laboratory experiments. After ozonation, the average TOC entering the contactors was 1,488 micrograms/liter, and the average effluent TOC was 497 micrograms/liter. Microbiological TOC removal was found to average 240 micrograms/liter on GAC contactors, which was not significantly different from microbiological TOC (220 micrograms/liter) removal across a parallel sand contactor where no adsorption took place. Thus, GAC did not appear to enhance biological TOC removal. Bacterial growth and maintenance was responsible for approximately 24% of the TOC removal on GAC under the conditions of this study. PMID:6639023

Assessment of bacterial growth and total organic carbon removal on granular activated carbon contactors.

Science.gov (United States)

Bancroft, K; Maloney, S W; McElhaney, J; Suffet, I H; Pipes, W O

1983-09-01

The overall growth rate of bacteria on granular activated carbon (GAC) contactors at the Philadelphia Torresdale Water Treatment Pilot Plant facility was found to decrease until steady state was reached. The growth rate was found to fluctuate between 6.94 X 10(-3) and 8.68 X 10(-4) doublings per h. The microbiological removal of total organic carbon (TOC) was calculated by considering the GAC contactors as semiclosed continuous culture systems and using growth yield factors determined in laboratory experiments. After ozonation, the average TOC entering the contactors was 1,488 micrograms/liter, and the average effluent TOC was 497 micrograms/liter. Microbiological TOC removal was found to average 240 micrograms/liter on GAC contactors, which was not significantly different from microbiological TOC (220 micrograms/liter) removal across a parallel sand contactor where no adsorption took place. Thus, GAC did not appear to enhance biological TOC removal. Bacterial growth and maintenance was responsible for approximately 24% of the TOC removal on GAC under the conditions of this study.

Water liquid-vapor interface subjected to various electric fields: A molecular dynamics study

Science.gov (United States)

Nikzad, Mohammadreza; Azimian, Ahmad Reza; Rezaei, Majid; Nikzad, Safoora

2017-11-01

Investigation of the effects of E-fields on the liquid-vapor interface is essential for the study of floating water bridge and wetting phenomena. The present study employs the molecular dynamics method to investigate the effects of parallel and perpendicular E-fields on the water liquid-vapor interface. For this purpose, density distribution, number of hydrogen bonds, molecular orientation, and surface tension are examined to gain a better understanding of the interface structure. Results indicate enhancements in parallel E-field decrease the interface width and number of hydrogen bonds, while the opposite holds true in the case of perpendicular E-fields. Moreover, perpendicular fields disturb the water structure at the interface. Given that water molecules tend to be parallel to the interface plane, it is observed that perpendicular E-fields fail to realign water molecules in the field direction while the parallel ones easily do so. It is also shown that surface tension rises with increasing strength of parallel E-fields, while it reduces in the case of perpendicular E-fields. Enhancement of surface tension in the parallel field direction demonstrates how the floating water bridge forms between the beakers. Finally, it is found that application of external E-fields to the liquid-vapor interface does not lead to uniform changes in surface tension and that the liquid-vapor interfacial tension term in Young's equation should be calculated near the triple-line of the droplet. This is attributed to the multi-directional nature of the droplet surface, indicating that no constant value can be assigned to a droplet's surface tension in the presence of large electric fields.

Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

Science.gov (United States)

Lawson, D. D.

1979-01-01

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Vapor-liquid equilibrium prediction with pseudo-cubic equation of state for binary mixtures containing hydrogen, helium, or neon

Energy Technology Data Exchange (ETDEWEB)

Kato, M.; Tanaka, H. (Nihon Univ.,Fukushima, (Japan). Faculty of Enineering)

1990-03-01

As an equation of state of vapor-liquid equilibrium, an original pseudo-cubic equation of state was previously proposed by the authors of this report and its study is continued. In the present study, new effective critical values of hydrogen, helium and neon were determined empirically from vapor-liquid equilibrium data of literature values against their critical temperatures, critical pressures and critical volumes. The vapor-liquid equilibrium relations of binary system quantum gas mixtures were predicted combining the conventinal pseudo-cubic equation of state and the new effective critical values, and without using binary heteromolecular interaction parameter. The predicted values of hydrogen-ethylene, helium-propane and neon-oxygen systems were compared with literature values. As a result, it was indicated that the vapor-liquid relations of binary system mixtures containing hydrogen, helium and neon can be predicted with favorable accuracy combining the effective critical values and the three parameter pseudo-cubic equation of state. 37 refs., 3 figs., 4 tabs.

Liquid-Vapor Argon Isotope Fractionation from the Triple Point to the Critical Point

DEFF Research Database (Denmark)

Phillips, J. T.; Linderstrøm-Lang, C. U.; Bigeleisen, J.

1972-01-01

are compared at the same molar volume. The isotope fractionation factor α for 36Ar∕40Ar between liquid and vapor has been measured from the triple point to the critical temperature. The results are compared with previous vapor pressure data, which cover the range 84–102°K. Although the agreement is within....... The fractionation factor approaches zero at the critical temperature with a nonclassical critical index equal to 0.42±0.02.〈∇2Uc〉/ρc in liquid argon is derived from the experimental fractionation data and calculations of 〈∇2Ug〉/ρg for a number of potential functions for gaseous argon....

Accomplishing equilibrium in ALSEP: demonstrations of modified process chemistry on 3-D printed enhanced annular centrifugal contactors

Energy Technology Data Exchange (ETDEWEB)

Brown, M.A.; Wardle, K.E.; Gelis, A.V. [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL, 60439 (United States); Lumetta, G. [Paccific Northwest National Laboratory, Richland, WA (United States)

2016-07-01

The ALSEP (Actinide Lanthanide Separation Process) was developed to treat a PUREX raffinate stream by liquid-liquid extraction with the intent of separating trivalent minor actinides (Am/Cm; An) from trivalent fission-product lanthanides (Ln) and selected transition metals. The major components of the modified ALSEP process have been demonstrated on a modified 2-cm annular centrifugal contactor with an enhanced mixing zone using stable fission products and radiotracers. The results show that by decreasing the pH of the minor actinide stripping solution, using HEDTA instead of DTPA, and increasing contact time, the process is very effective in separating americium from the lanthanides and the fission products.

Normal coordinate treatment of liquid water and calculation of vapor pressure isotope effects

International Nuclear Information System (INIS)

Gellai, B.; Van Hook, W.A.

1983-01-01

A vibrational analysis of liquid water is reported, assuming a completely hydrogen-bonded network with continuously varying strengths of the hydrogen bonds. Frequency distribution calculations are made for intramolecular stretching and bending modes and for the intramolecular frequency region. The calculated distributions are compared with the experimental spectroscopic ones. As another test, vapor pressure isotope effects are calculated from the theoretical distributions for some isotopic water molecules. Results are compared with those of other authors obtained from a mixture model. (author)

Nucleation and growth of vapor bubbles in the liquid bulk and at a solid surface

International Nuclear Information System (INIS)

Yagov, V.V.

1977-01-01

The main achievements in the study of the vapor phase origin in liquid and the subsequent growth of the vapor bubbles are presented briefly, and a number of issues on which there is no single opinion as yet are also outlined. The theory of homogeneous nucleation and a great number of experiments make it possible not only to explain qualitatively the causes of spontaneous formation of vapor nucleation centers in the metastable liquid but provides a simple computational relation for the estimating the intensity of this process. None of the existing hypotheses, however, can give a complete answer to the question of the mechanism of the vapor phase nucleation on a solid surface under ''pure conditions'', although this is a more pressing problem. At the same time, the role of cavities of reservoir type (with a narrow orifice) on the surface under heating as reliable stabilizers of the vapor formation (especially in liquid metals) is clarified from the practical point of view. Thus, the identification of technology for production of such cavities would make it possible to increase substantially the efficiency of heat transferring surfaces. Any computational relations for the growth of bubbles on the heating surface also are (and, according to the author, necessarily will be) approximate ones, although considerable success has been achieved in this field

ISS modeling strategy for the numerical simulation of turbulent sub-channel liquid-vapor flows

International Nuclear Information System (INIS)

Olivier Lebaigue; Benoit Mathieu; Didier Jamet

2005-01-01

Full text of publication follows: The general objective is to perform numerical simulation of the liquid-vapor turbulent two-phase flows that occur in sub-channels of a nuclear plant assembly under nominal or incidental situations. Additional features concern nucleate boiling at the surface of fuel rods and the sliding of vapor bubbles on this surface with possible dynamic contact lines. The Interfaces and Sub-grid Scales (ISS) modeling strategy for numerical simulations is one of the possible two-phase equivalents for the one-phase LES concept. It consists in solving the two-phase flows features at the scales that are resolved by the grid of the numerical method, and to take into account the unresolved scales with sub-grid models. Interfaces are tracked in a DNS-like approach while specific features of the behavior of interfaces such as contact line physics, coalescence and fragmentation, and the smallest scales of turbulence within each phase have an unresolved scale part that is modeled. The problem of the modeling of the smallest scales of turbulence is rather simple even if the classical situation is altered by the presence of the interfaces. In a typical sub-channel situation (e.g., 15 MPa and 3.5 m.s -1 water flow in a PWR sub-channel), the Kolmogorov scale is ca. 1 μm whereas typical bubble size are supposed to be close to 150 μm. Therefore, the use of a simple sub-grid model between, e.g., 1 and 20 μm allows a drastic reduction of the number of nodes in the space discretization while it remains possible to validate by comparison to true DNS results. Other sub-grid models have been considered to recover physical phenomena that cannot be captured with a realistic discretization: they rely on physical scales from molecular size to 1 μm. In these cases, the use of sub-grid model is no longer a matter of CPU-time and memory saving only, but also a corner stone to recover physical behavior. From this point of view at least we are no longer performing true

Development of a selection support expert system of mathematical models for dynamic simulation of liquid-vapor two-phase flow

International Nuclear Information System (INIS)

Gofuku, Akio; Shimizu, Kenji; Sugano, Keiji; Morimoto, Takashi; Yoshikawa, Hidekazu; Wakabayashi, Jiro

1992-01-01

This paper deals with computerized supporting techniques of a numerical simulation of complex and large-scale engineering systems like nuclear power plants. As an example of the intelligent support systems of dynamic simulation, a prototype expert system is developed on an expert system development tool to support the selection of mathematical model which is a first step of numerical simulation and is required both wide expert knowledge and high-level decision making. The expert system supports the selection of liquid-vapor two phase flow models (fluid model and constitutive equations) consistent with simulation purpose and condition in the case of thermal-hydraulic simulation of nuclear power plants. The possibility of the expert system is examined for various selection support cases by both investigation of the appropriateness of the selection support logic and comparison between support results and decision results of several experts. (author)

Making sense of enthalpy of vaporization trends for ionic liquids: new experimental and simulation data show a simple linear relationship and help reconcile previous data.

Science.gov (United States)

Verevkin, Sergey P; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Yermalayeu, Andrei V; Schick, Christoph; Liu, Hongjun; Maginn, Edward J; Bulut, Safak; Krossing, Ingo; Kalb, Roland

2013-05-30

Vaporization enthalpy of an ionic liquid (IL) is a key physical property for applications of ILs as thermofluids and also is useful in developing liquid state theories and validating intermolecular potential functions used in molecular modeling of these liquids. Compilation of the data for a homologous series of 1-alkyl-3-methylimidazolium bis(trifluoromethane-sulfonyl)imide ([C(n)mim][NTf2]) ILs has revealed an embarrassing disarray of literature results. New experimental data, based on the concurring results from quartz crystal microbalance, thermogravimetric analyses, and molecular dynamics simulation have revealed a clear linear dependence of IL vaporization enthalpies on the chain length of the alkyl group on the cation. Ambiguity of the procedure for extrapolation of vaporization enthalpies to the reference temperature 298 K was found to be a major source of the discrepancies among previous data sets. Two simple methods for temperature adjustment of vaporization enthalpies have been suggested. Resulting vaporization enthalpies obey group additivity, although the values of the additivity parameters for ILs are different from those for molecular compounds.

A new method for the determination of vaporization enthalpies of ionic liquids at low temperatures.

Science.gov (United States)

Verevkin, Sergey P; Zaitsau, Dzmitry H; Emelyanenko, Vladimir N; Heintz, Andreas

2011-11-10

A new method for the determination of vaporization enthalpies of extremely low volatile ILs has been developed using a newly constructed quartz crystal microbalance (QCM) vacuum setup. Because of the very high sensitivity of the QCM it has been possible to reduce the average temperature of the vaporization studies by approximately 100 K in comparison to other conventional techniques. The physical basis of the evaluation procedure has been developed and test measurements have been performed with the common ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(2)mim][NTf(2)] extending the range of measuring vaporization enthalpies down to 363 K. The results obtained for [C(2)mim][NTf(2)] have been tested for thermodynamic consistency by comparison with data already available at higher temperatures. Comparison of the temperature-dependent vaporization enthalpy data taken from the literature show only acceptable agreement with the heat capacity difference of -40 J K(-1) mol(-1). The method developed in this work opens also a new way to obtain reliable values of vaporization enthalpies of thermally unstable ionic liquids.

Investigation of Real-Time Two-Dimensional Visualization of Fuel Spray Liquid/Vapor Distribution via Exciplex Fluorescence.

Science.gov (United States)

1987-08-30

EXCIPLEX FLUORESCENCE ~N 0FINAL REPORT 00 JAMES F. VERDIECK AND ARTHUR A. ROTUNNO UNITED TECHNOLOGIES RESEARCH CENTER 0 AND LYNN A. MELTON D I UNIVERSITY...DOCUMENTATION. "NWA 0. INVESTIGATION OF REAL-TINE TWO-DIMENSIONAL VISUALIZATION OF FUEL SPRAY LIQUID/VAPOR DISTRIBUTION VIA EXCIPLEX FLUORESCENCE FINAL...Spray Liquid/Vapor Distribution Via Exciplex Fluorescen , - 12. PERSONAL AUTHOR(S) J. F. Yeardierk. A- A. Rnriiunn-l L_ A. Millo - 13a TYPE OF REPORT

DETERMINATION OF HEAT TRANSFER COEFFICIENTS FOR FRENCH PLASTIC SEMEN STRAW SUSPENDED IN STATIC NITROGEN VAPOR OVER LIQUID NITROGEN.

Science.gov (United States)

Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N

2015-01-01

The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

Characterization of the TIP4P-Ew water model: vapor pressure and boiling point.

Science.gov (United States)

Horn, Hans W; Swope, William C; Pitera, Jed W

2005-11-15

The liquid-vapor-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the vapor pressure curve obtained from simulated free-energy changes is in excellent agreement with the experimental vapor pressure curve. The boiling point of TIP4P-Ew water under ambient pressure is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K; from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the vapor pressure results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water.

THE TESTING OF COMMERCIALLY AVAILABLE ENGINEERING AND PLANT SCALE ANNULAR CENTRIFUGAL CONTACTORS FOR THE PROCESSING OF SPENT NUCLEAR FUEL

International Nuclear Information System (INIS)

Jack D. Law; David Meikrantz; Troy Garn; Nick Mann; Scott Herbst

2006-01-01

Annular centrifugal contactors are being evaluated for process scale solvent extraction operations in support of United State Advanced Fuel Cycle Initiative goals. These contactors have the potential for high stage efficiency if properly employed and optimized for the application. Commercially available centrifugal contactors are being tested at the Idaho National Laboratory to support this program. Hydraulic performance and mass transfer efficiency have been measured for portions of an advanced nuclear fuel cycle using 5-cm diameter annular centrifugal contactors. Advanced features, including low mix sleeves and clean-in-place rotors, have also been evaluated in 5-cm and 12.5-cm contactors

A model for acoustic vaporization dynamics of a bubble/droplet system encapsulated within a hyperelastic shell.

Science.gov (United States)

Lacour, Thomas; Guédra, Matthieu; Valier-Brasier, Tony; Coulouvrat, François

2018-01-01

Nanodroplets have great, promising medical applications such as contrast imaging, embolotherapy, or targeted drug delivery. Their functions can be mechanically activated by means of focused ultrasound inducing a phase change of the inner liquid known as the acoustic droplet vaporization (ADV) process. In this context, a four-phases (vapor + liquid + shell + surrounding environment) model of ADV is proposed. Attention is especially devoted to the mechanical properties of the encapsulating shell, incorporating the well-known strain-softening behavior of Mooney-Rivlin material adapted to very large deformations of soft, nearly incompressible materials. Various responses to ultrasound excitation are illustrated, depending on linear and nonlinear mechanical shell properties and acoustical excitation parameters. Different classes of ADV outcomes are exhibited, and a relevant threshold ensuring complete vaporization of the inner liquid layer is defined. The dependence of this threshold with acoustical, geometrical, and mechanical parameters is also provided.

A Liquid Desiccant Cycle for Dehumidification and Fresh Water Supply in Controlled Environment Agriculture

KAUST Repository

Lefers, Ryan

2017-12-01

Controlled environment agriculture allows the production of fresh food indoors from global locations and contexts where it would not otherwise be possible. Growers in extreme climates and urban areas produce food locally indoors, saving thousands of food import miles and capitalizing upon the demand for fresh, tasty, and nutritious food. However, the growing of food, both indoors and outdoors, consumes huge quantities of water - as much as 70-80% of global fresh water supplies. The utilization of liquid desiccants in a closed indoor agriculture cycle provides the possibility of capturing plant-transpired water vapor. The regeneration/desalination of these liquid desiccants offers the potential to recover fresh water for irrigation and also to re-concentrate the desiccants for continued dehumidification. Through the utilization of solar thermal energy, the process can be completed with a very small to zero grid-energy footprint. The primary research in this dissertation focused on two areas: the dehumidification of indoor environments utilizing liquid desiccants inside membrane contactors and the regeneration of these desiccants using membrane distillation. Triple-bore PVDF hollow fiber membranes yielded dehumidification permeance rates around 0.25-0.31 g m-2 h-1 Pa-1 in lab-scale trials. A vacuum membrane distillation unit utilizing PVDF fibers yielded a flux of 2.8-7.0 kg m-2 hr-1. When the membrane contactor dehumidification system was applied in a bench scale controlled environment agriculture setup, the relative humidity levels responded dynamically to both plant transpiration and dehumidification rates, reaching dynamic equilibrium levels during day and night cycles. In addition, recovered fresh water from distillation was successfully applied for irrigation of crops and concentrated desiccants were successfully reused for dehumidification. If applied in practice, the liquid desiccant system for controlled environment agriculture offers the potential to reduce

Microspheres for the Growth of Silicon Nanowires via Vapor-Liquid-Solid Mechanism

Directory of Open Access Journals (Sweden)

Arancha Gómez-Martínez

2014-01-01

Full Text Available Silicon nanowires have been synthesized by a simple process using a suitable support containing silica and carbon microspheres. Nanowires were grown by thermal chemical vapor deposition via a vapor-liquid-solid mechanism with only the substrate as silicon source. The curved surface of the microsized spheres allows arranging the gold catalyst as nanoparticles with appropriate dimensions to catalyze the growth of nanowires. The resulting material is composed of the microspheres with the silicon nanowires attached on their surface.

Applicability of hydroxylamine nitrate reductant in pulse-column contactors

International Nuclear Information System (INIS)

Reif, D.J.

1983-05-01

Uranium and plutonium separations were made from simulated breeder reactor spent fuel dissolver solution with laboratory-sized pulse column contactors. Hydroxylamine nitrate (HAN) was used for reduction of plutonium (1V). An integrated extraction-partition system, simulating a breeder fuel reprocessing flowsheet, carried out a partial partition of uranium and plutonium in the second contactor. Tests have shown that acceptable coprocessing can be ontained using HAN as a plutonium reductant. Pulse column performance was stable even though gaseous HAN oxidation products were present in the column. Gas evolution rates up to 0.27 cfm/ft 2 of column cross section were tested and found acceptable

High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

Energy Technology Data Exchange (ETDEWEB)

Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail: fgarcias@imp.mx; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)

2007-06-15

In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

International Nuclear Information System (INIS)

Garcia-Sanchez, Fernando; Eliosa-Jimenez, Gaudencio; Silva-Oliver, Guadalupe; Godinez-Silva, Armando

2007-01-01

In this work, new (vapor + liquid) equilibrium data for the (N 2 + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N 2 + n-heptane) system

A non-equilibrium model for soil heating and moisture transport during extreme surface heating: The soil (heat-moisture-vapor) HMV-Model Version

Science.gov (United States)

William Massman

2015-01-01

Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMVmodel, a 1-D (one-dimensional) non-equilibrium (liquid- vapor phase change)...

Liquid-Vapor Phase Transition: Thermomechanical Theory, Entropy Stable Numerical Formulation, and Boiling Simulations

Science.gov (United States)

2015-05-01

vapor bubbles may generate near blades [40]. This is the phenomenon of cavitation and it is still a limiting factor for ship propeller design. Phase...van der Waals theory with hydrodynamics [39]. The fluid equations based on the van der Waals theory are called the Navier-Stokes-Korteweg equations... cavitating flows, the liquid- vapor phase transition induced by pressure variations. A potential challenge for such a simulation is a proper design of open

Evaluation of (vapor + liquid) equilibria for the binary systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol compositions

International Nuclear Information System (INIS)

Ovejero, Gabriel; Dolores Romero, M.; Diez, Eduardo; Lopes, Tania; Diaz, Ismael

2008-01-01

Isobaric (vapor + liquid) equilibrium at p = 101.32 kPa of pressure has been determined for the systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol mole fractions. These data were satisfactorily correlated, using ASPEN PLUS commercial software, with Wilson, NRTL, and UNIQUAC activity coefficient models to obtain the binary interaction parameters of both mixtures. Also, UNIFAC group contribution method was employed to predict the equilibrium of both mixtures. With regression values an accurate knowledge of (vapor + liquid) equilibrium for both mixtures can be reached in a range of 1-octanol mole fractions less than 0.1. UNIFAC method provides acceptable results for (1-octanol + n-hexane) system but not for (1-octanol + cyclohexane) system

Evaluation of (vapor + liquid) equilibria for the binary systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol compositions

Energy Technology Data Exchange (ETDEWEB)

Ovejero, Gabriel [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)], E-mail: govejero@quim.ucm.es; Dolores Romero, M.; Diez, Eduardo; Lopes, Tania; Diaz, Ismael [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de C. Quimicas, Universidsad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

2008-11-15

Isobaric (vapor + liquid) equilibrium at p = 101.32 kPa of pressure has been determined for the systems (1-octanol + cyclohexane) and (1-octanol + n-hexane), at low alcohol mole fractions. These data were satisfactorily correlated, using ASPEN PLUS commercial software, with Wilson, NRTL, and UNIQUAC activity coefficient models to obtain the binary interaction parameters of both mixtures. Also, UNIFAC group contribution method was employed to predict the equilibrium of both mixtures. With regression values an accurate knowledge of (vapor + liquid) equilibrium for both mixtures can be reached in a range of 1-octanol mole fractions less than 0.1. UNIFAC method provides acceptable results for (1-octanol + n-hexane) system but not for (1-octanol + cyclohexane) system.

Review of enhanced vapor diffusion in porous media

International Nuclear Information System (INIS)

Webb, S.W.; Ho, C.K.

1998-01-01

Vapor diffusion in porous media in the presence of its own liquid has often been treated similar to gas diffusion. The gas diffusion rate in porous media is much lower than in free space due to the presence of the porous medium and any liquid present. However, enhanced vapor diffusion has also been postulated such that the diffusion rate may approach free-space values. Existing data and models for enhanced vapor diffusion, including those in TOUGH2, are reviewed in this paper

Estimating enthalpy of vaporization from vapor pressure using Trouton's rule.

Science.gov (United States)

MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

2007-04-15

The enthalpy of vaporization of liquids and subcooled liquids at 298 K (delta H(VAP)) is an important parameter in environmental fate assessments that consider spatial and temporal variability in environmental conditions. It has been shown that delta H(VAP)P for non-hydrogen-bonding substances can be estimated from vapor pressure at 298 K (P(L)) using an empirically derived linear relationship. Here, we demonstrate that the relationship between delta H(VAP)and PL is consistent with Trouton's rule and the ClausiusClapeyron equation under the assumption that delta H(VAP) is linearly dependent on temperature between 298 K and the boiling point temperature. Our interpretation based on Trouton's rule substantiates the empirical relationship between delta H(VAP) degree and P(L) degrees for non-hydrogen-bonding chemicals with subcooled liquid vapor pressures ranging over 15 orders of magnitude. We apply the relationship between delta H(VAP) degrees and P(L) degrees to evaluate data reported in literature reviews for several important classes of semivolatile environmental contaminants, including polycyclic aromatic hydrocarbons, chlorobenzenes, polychlorinated biphenyls and polychlorinated dibenzo-dioxins and -furans and illustrate the temperature dependence of results from a multimedia model presented as a partitioning map. The uncertainty associated with estimating delta H(VAP)degrees from P(L) degrees using this relationship is acceptable for most environmental fate modeling of non-hydrogen-bonding semivolatile organic chemicals.

Stage wise modeling of liquid-extraction column (RDC)

International Nuclear Information System (INIS)

Bastani, B.

2004-01-01

Stage wise forward mixing model considering coalescence and re dispersion of drops was used to predict the performance of Rotating Disk Liquid Extraction Contactors. Experimental data previously obtained in two RDC columns of 7-62 cm diameter, 73.6 cm height and 21.9 cm diameter,150 cm height were used to evaluate the model predications. Drops-side mass transfer coefficients were predicted applying Hand los-baron drop model and onley's model was used to predict velocities. According to the results obtained the followings could be concluded: (1) If the height of coalescence and re dispersion i.e.:h=h p Q p / Q could be estimated, the stage wise forward mixing with coalescence and re dispersion model will predict the column height and efficiency with the acceptable accuracy, (2) The stage wise modeling predictions are highly dependent on the number of stages used when the number of stages is less than 10 and (3) Application of continuous phase mass transfer axial dispersion coefficients (k c and E c ) obtained from the solute concentration profile along the column height will predict the column performance more accurately than the Calder bank and moo-young (for K c ) and Kumar-Heartland (for E c ) correlations

Vaporization enthalpies of imidazolium based ionic liquids. A thermogravimetric study of the alkyl chain length dependence

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Zaitsau, Dzmitry H.; Emel’yanenko, Vladimir N.; Ralys, Ricardas V.; Yermalayeu, Andrei V.; Schick, Christoph

2012-01-01

Highlights: ► Enthalpies of vaporization of ionic liquids were measured with thermogravimetry. ► We studied 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide. ► The linear alkyl chain length was 4, 6, 8, 10, 12, 14, 16, and 18 C-atoms. ► A linear dependence on the chain length of the alkyl-imidazolium cation was found. - Abstract: Vaporization enthalpies for a series of ten ionic liquids (ILs) 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide [C n mim][NTf 2 ], with the alkyl chain length n = 4, 6, 8, 10, 12, 14, 16, and 18 were determined using the thermogravimetric method. An internally consistent set of experimental data and vaporization enthalpies at 540 K was obtained. Vaporization enthalpies at 540 K have shown a linear dependence on the chain length of the alkyl-imidazolium cation in agreement with the experimental results measured previously with a quartz crystal microbalance. Ambiguity of Δ l g C pm o -values required for the extrapolation of experimental vaporization enthalpies to the reference temperature 298 K has been discussed.

Vapor-transport of tungsten and its geologic application

Energy Technology Data Exchange (ETDEWEB)

Shibue, Y [Hyogo Univ. of Teacher Education, Hyogo (Japan)

1988-11-10

The volatility of tungsten in a hydrous system at elevated temperatures and pressures was examined, and a tentative model for the enrichment of tungsten in hydrothermal solutions for the deposits related to granitic activities was proposed. To produce vapor-saturated solution, 17 or 15ml of 20wt% NaCl solution was introduced into an autoclave. Ca(OH){sub 2} for tungsten and H{sub 2}WO{sub 4} for base metals were used as vapor-captures, and run products were identified by X-ray powder diffractometry. The results suggested that the ratio of tungsten to base metals was higher in a vapor phase than in a liquid phase, and more enrichment of tungsten in the vapor phase occurred at higher temperature and pressure under the coexistence of the vapor and liquid phase. The tentative model emphasizing the vapor-transport of tungsten could explain the presence of tungsten deposits without large mineralization of base metals. Geological schematic model for the generation of the hydrothermal solution enriched in tungsten compared with base metals was illustrated based on above mentioned results. 21 refs., 3 figs.

R-22 vapor explosions

International Nuclear Information System (INIS)

Anderson, R.P.; Armstrong, D.R.

1977-01-01

Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

A Local Propagation for Vapor Explosions

International Nuclear Information System (INIS)

Ochiai, M.; Bankoff, S.G.

1976-01-01

Explosive boiling, defined as energy transfer leading to formation of vapor rapidly enough to produce large shock waves, has been widely studied in a number of contexts. Depending upon the nature and temperatures of the liquids and mode of contacting, large-scale mixing and explosive vaporization may occur, or alternatively, only relatively non-energetic, film-type boiling may exist. The key difference is whether a mechanism is operative for increasing the liquid-liquid interfacial area in a time scale consistent with the formation of a detonation wave. Small drops of a cold volatile liquid were dropped onto a free surface of a hot, non-volatile liquid. The critical Weber number for coalescence is obtained from the envelope of the film boiling region. Markedly different behavior for the two hot liquids is observed. A 'splash' theory for local propagation of vapor explosions in spontaneously nucleating liquid-liquid systems is now formulated. After a random contact is made, explosive growth and coalescence of the vapor bubbles occurs as soon as the surrounding pressure is relieved, resulting in a high-pressure vapor layer at the liquid-liquid contact area. This amounts to an impact pressure applied to the free surface, with a resulting velocity distribution obtained from potential flow theory. The peak pressure predictions are. consistent with data for Freon-oil mixing, but further evaluation will await additional experimental data. Nevertheless, the current inference is that a UO 2 -Na vapor explosion in a reactor environment cannot be visualized. In conclusion: The propagation model presented here differs in some details from that of Henry and Fauske, although both are consistent with some peak pressure data obtained by Henry, et al. Clearly, additional experimental information is needed for further evaluation of these theories. Nevertheless, it should be emphasized that even at this time a number of important observations concerning the requirements for a vapor

Vaporization of liquid Pb-Li eutectic alloy from 1000K to 1200K - A high temperature mass spectrometric study

Science.gov (United States)

Jain, U.; Mukherjee, A.; Dey, G. K.

2017-09-01

Liquid lead-lithium eutectic will be used as a coolant in fusion reactor blanket loop. Vapor pressure of the eutectic is an important parameter to accurately predict its in-loop behavior. Past measurements of vapor pressure of the eutectic relied on indirect methods. In this paper, we report for the first time the in-situ vaporization behavior of the liquid alloy between 1042 and 1176 K by Knudsen effusion mass spectrometry (KEMS). It was seen that the vaporization occurred by independent evaporation of lead and lithium. No complex intermetallic vapor was seen in the mass spectra. The partial pressures and enthalpy of vaporization of Pb and Li were evaluated directly from the measured ion intensities formed from the equilibrium vapor over the alloy. The activity of Li over a temperature range of 1042-1176 K was found to be 4.8 × 10-5 to that of pure Li, indicating its very low activity in the alloy.

High Pressure Vapor-Liquid Equilibrium of Supercritical Carbon Dioxide + n-Hexane System

Institute of Scientific and Technical Information of China (English)

YU Jinglin; TIAN Yiling; ZHU Rongjiao; LIU Zhihua

2006-01-01

Vapor-liquid equilibrium data of supercritical carbon dioxide + n-hexane system were measured at 313.15 K,333.15 K,353.15 K,and 373.15 K and their molar volumes and densities were measured both in the subcritical and supercritical regions ranging from 2.15 to 12.63 MPa using a variable-volume autoclave.The thermodynamic properties including mole fractions,densities,and molar volumes of the system were calculated with an equation of state by Heilig and Franck,in which a repulsion term and a square-well potential attraction term for intermolecular interaction was used.The pairwise combination rule was used to calculate the square-well molecular interaction potential and three adjustable parameters (ω,kε,kσ) were obtained.The Heilig-Franck equation of state is found to have good correlation with binary vapor-liquid equilibrium data of the carbon dioxide + n-hexane system.

Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

Science.gov (United States)

Yoshikawa, Masahiro; Koga, Nobuyoshi

2016-01-01

This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

Solvent Carryover Characterization and Recovery for a 10-inch Single Stage Centrifugal Contactor

International Nuclear Information System (INIS)

Lentsch, R.D.; Stephens, A.B.; Leung, D.T.; Baffling, K.E.; Harmon, H.D.; Suggs, P.C.

2006-01-01

A test program has been performed to characterize the organic solvent carryover and recovery from centrifugal contactors in the Caustic-side Solvent Extraction (CSSX) process. CSSX is the baseline design for removing cesium from salt solutions for Department of Energy (DOE) Savannah River Site's Salt Waste Processing Facility. CSSX uses a custom solvent to extract cesium from the salt solution in a series of single stage centrifugal contactors. Meeting the Waste Acceptance Criteria at the Defense Waste Processing Facility and Saltstone, as well as plant economics, dictate that solvent loss should be kept to a minimum. Solvent droplet size distribution in the aqueous outlet streams of the CSSX contactors is of particular importance to the design of solvent recovery equipment. Because insufficient solvent droplet size data existed to form a basis for the recovery system design, DOE funded the CSSX Solvent Carryover Characterization and Recovery Test (SCCRT). This paper presents the droplet size distribution of solvent and concentration in the contactor aqueous outlet streams as a function of rotor speed, bottom plate type, and flow rate. It also presents the performance data of a prototype coalescer. (authors)

The processes of vaporization in the porous structures working with the excess of liquid

Directory of Open Access Journals (Sweden)

Genbach Alexander A.

2017-01-01

Full Text Available The processes of vaporization in porous structures, working with the excess of liquid are investigated. With regard to the thermal power plants new porous cooling system is proposed and investigated, in which the supply of coolant is conducted by the combined action of gravity and capillary forces. The cooling surface is made of stainless steel, brass, copper, bronze, nickel, alundum and glass, with wall thickness of (0.05-2•10-3 m. Visualizations of the processes of vaporization were carried out using holographic interferometry with the laser system and high speed camera. The operating conditions of the experiments were: water pressures (0.01-10 MPa, the temperature difference of sub-cooling (0-20°C, an excess of liquid (1-14 of the steam flow, the heat load (1-60•104 W/m2, the temperature difference (1-60°C and orientation of the system (± 0 - ± 90 degrees. Studies have revealed three areas of liquid vaporization process (transitional, developed and crisis. The impact of operating and design parameters on the integrated and thermal hydraulic characteristics was defined. The optimum (minimum flow rate of cooling fluid and the most effective type of mesh porous structure were also defined.

The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

2007-04-04

Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

Empirical model for calculating vapor-liquid equilibrium and associated phase enthalpy for the CO2--O2--Kr--Xe system for application to the KALC process

International Nuclear Information System (INIS)

Glass, R.W.; Gilliam, T.M.; Fowler, V.L.

1976-01-01

An empirical model is presented for vapor-liquid equilibria and enthalpy for the CO 2 -O 2 system. In the model, krypton and xenon in very low concentrations are combined with the CO 2 -O 2 system, thereby representing the total system of primary interest in the High-Temperature Gas-Cooled Reactor program for removing krypton from off-gas generated during the reprocessing of spent fuel. Selected properties of the individual and combined components being considered are presented in the form of tables and empirical equations

Liquid and vapor phase fluids visualization using an exciplex chemical sensor

International Nuclear Information System (INIS)

Kim, Jong Uk; Kim, Guang Hoon; Kim, Chang Bum; Suk, Hyyong

2001-01-01

Two dimensional slices of the cross-sectional distributions of fuel images in the combustion chamber were visualized quantitatively using a laser-induced exciplex (excited state complex) fluorescence technique. A new exciplex visualization system consisting of 5%DMA (N, N-dimethylaniline) · 5%1, 4,6-TMN (trimethylnaphthalene) in 90% isooctane (2,2,4-trimethylpentane) fuel was employed. In this method, the vapor phase was tagged by the monomer fluorescence while the liquid phase was tracked by the red-shifted exciplex fluorescence with good spectral and spatial resolution. The direct calibration of the fluorescence intensity as a function of the fluorescing dopant concentrations then permitted the determination of quantitative concentration maps of liquid and vapor phases in the fuel. The 308 nm (XeCl) line of the excimer laser was used to excite the doped molecules in the fuel and the resulting fluorescence images were obtained with an ICCD detector as a function time. In this paper, the spectroscopy of the exciplex chemical sensors as well as the optical diagnostic method of the fluid distribution is discussed in detail.

CO2 Capture with Liquid-Liquid Phase Change Solvents: A Thermodynamic Study

DEFF Research Database (Denmark)

Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas

2017-01-01

by the quaternary H2O-DEEAMAPA-CO2 system which gives liquid-liquid phase split when reacted with carbon dioxide. A total of 94 model parameters and 6 thermodynamic properties were fitted to approximately 1500 equilibrium and thermal experimental data consisting of pureamine vapor pressure (Pvap), vapor...

Vapor-Liquid-Solid Etch of Semiconductor Surface Channels by Running Gold Nanodroplets.

Science.gov (United States)

Nikoobakht, Babak; Herzing, Andrew; Muramoto, Shin; Tersoff, Jerry

2015-12-09

We show that Au nanoparticles spontaneously move across the (001) surface of InP, InAs, and GaP when heated in the presence of water vapor. As they move, the particles etch crystallographically aligned grooves into the surface. We show that this process is a negative analogue of the vapor-liquid-solid (VLS) growth of semiconductor nanowires: the semiconductor dissolves into the catalyst and reacts with water vapor at the catalyst surface to create volatile oxides, depleting the dissolved cations and anions and thus sustaining the dissolution process. This VLS etching process provides a new tool for directed assembly of structures with sublithographic dimensions, as small as a few nanometers in diameter. Au particles above 100 nm in size do not exhibit this process but remain stationary, with oxide accumulating around the particles.

Equilibrium vapor-liquid-crystal in Sn-In-P system

International Nuclear Information System (INIS)

Ermilin, V.N.; Selin, A.A.; Khukhryanskij, Yu.P.

1991-01-01

Using flow method the dependence of phosphorus vapor pressure was investigated on the composition of equilibrium with indium phosphide crystal of Sn-In-P system melt (x P l ≤x In l ) and temperature (in the range 918 to 978 K). Its multiplicative character conditioned by change in phosphorus solubility in liquid phase and reconstruction of internal structure of the melt was established. It is revealed that in the considered melts phosphorus is in atomic form (possible as In n P complexes)

Sodium vapor deposition onto a horizontal flat plate above liquid sodium surface, 2

International Nuclear Information System (INIS)

Kudo, Kazuhiko; Hirata, Masaru.

1977-01-01

The sodium vapor deposition onto a horizontal flat plate above liquid sodium surface was studied. The analysis was performed by assuming that the sodium mist is emitted into the main flow without condensation and then grows up in the main flow and drops on the sodium surface. The effects of growth of sodium mist to the system were investigated. The model of the phenomena is the sodium deposition onto a horizontal flat plate which is placed above the sodium surface with the medium cover gas. One-dimensional analysis can be done. The rate of deposition is greatly reduced when the temperature of the flat plate is lowered. For the analysis of this phenomena, it is assumed that the sodium mist grows by condensation. One of results is that the real state may be the state between the state that the condensation of mist is made in the boundary layer and the state that the mist is condensed in the main flow. Others are that there is no effect of sodium mist condensation on the rate of deposition, and that the rate of the vaporization of sodium is given by the original and the modified model. (Kato, T.)

Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry.

Science.gov (United States)

Taber Wanstall, C; Agrawal, Ajay K; Bittle, Joshua A

2017-10-20

The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recorded by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.

Generalized modeling of multi-component vaporization/condensation phenomena for multi-phase-flow analysis

International Nuclear Information System (INIS)

Morita, K.; Fukuda, K.; Tobita, Y.; Kondo, Sa.; Suzuki, T.; Maschek, W.

2003-01-01

A new multi-component vaporization/condensation (V/C) model was developed to provide a generalized model for safety analysis codes of liquid metal cooled reactors (LMRs). These codes simulate thermal-hydraulic phenomena of multi-phase, multi-component flows, which is essential to investigate core disruptive accidents of LMRs such as fast breeder reactors and accelerator driven systems. The developed model characterizes the V/C processes associated with phase transition by employing heat transfer and mass-diffusion limited models for analyses of relatively short-time-scale multi-phase, multi-component hydraulic problems, among which vaporization and condensation, or simultaneous heat and mass transfer, play an important role. The heat transfer limited model describes the non-equilibrium phase transition processes occurring at interfaces, while the mass-diffusion limited model is employed to represent effects of non-condensable gases and multi-component mixture on V/C processes. Verification of the model and method employed in the multi-component V/C model of a multi-phase flow code was performed successfully by analyzing a series of multi-bubble condensation experiments. The applicability of the model to the accident analysis of LMRs is also discussed by comparison between steam and metallic vapor systems. (orig.)

Determination of the solid-liquid-vapor triple point pressure of carbon

International Nuclear Information System (INIS)

Haaland, D.M.

1976-01-01

A detailed experimental study of the triple point pressure of carbon using laser heating techniques has been completed. Uncertainties and conflict in previous investigations have been addressed and substantial data presented which places the solid-liquid-vapor carbon triple point at 107 +- 2 atmospheres. This is in agreement with most investigations which have located the triple point pressure between 100 and 120 atmospheres, but is in disagreement with recent low pressure carbon experiments. The absence of any significant polymorphs of carbon other than graphite suggests that the graphite-liquid-vapor triple point has been measured. Graphite samples were melted in a pressure vessel using a 400 W Nd:YAG continuous-wave laser focused to a maximum power density of approximately 80 kW/cm 2 . Melt was confirmed by detailed microstructure analysis and x-ray diffraction of the recrystallized graphite. Experiments to determine the minimum melt pressure of carbon were completed as a function of sample size, type of inert gas, and laser power density to asure that laser power densities were sufficient to produce melt at the triple point pressure of carbon, and the pressure of carbon at the surface of the sample was identical to the measured pressure of the inert gas in the pressure vessel. High-speed color cinematography of the carbon heating revealed the presence of a laser-generated vapor or particle plume in front of the sample. The existence of this bright plume pevented the measurement of the carbon triple point temperature

One-dimensional three-field model of condensation in horizontal countercurrent flow with supercritical liquid velocity

International Nuclear Information System (INIS)

Trewin, Richard R.

2011-01-01

Highlights: → CCFL in the hot leg of a PWR with ECC Injection. → Three-Field Model of counter flowing water film and entrained droplets. → Flow of steam can cause a hydraulic jump in the supercritical flow of water. → Condensation of steam on subcooled water increases the required flow for hydraulic jump. → Better agreement with UPTF experimental data than Wallis-type correlation. - Abstract: A one-dimensional three-field model was developed to predict the flow of liquid and vapor that results from countercurrent flow of water injected into the hot leg of a PWR and the oncoming steam flowing from the upper plenum. The model solves the conservation equations for mass, momentum, and energy in a continuous-vapor field, a continuous-liquid field, and a dispersed-liquid (entrained-droplet) field. Single-effect experiments performed in the upper plenum test facility (UPTF) of the former SIEMENS KWU (now AREVA) at Mannheim, Germany, were used to validate the countercurrent flow limitation (CCFL) model in case of emergency core cooling water injection into the hot legs. Subcooled water and saturated steam flowed countercurrent in a horizontal pipe with an inside diameter of 0.75 m. The flow of injected water was varied from 150 kg/s to 400 kg/s, and the flow of steam varied from 13 kg/s to 178 kg/s. The subcooling of the liquid ranged from 0 K to 104 K. The velocity of the water at the injection point was supercritical (greater than the celerity of a gravity wave) for all the experiments. The three-field model was successfully used to predict the experimental data, and the results from the model provide insight into the mechanisms that influence the flows of liquid and vapor during countercurrent flow in a hot leg. When the injected water was saturated and the flow of steam was small, all or most of the injected water flowed to the upper plenum. Because the velocity of the liquid remained supercritical, entrainment of droplets was suppressed. When the injected

Linear Stability Analysis of an Acoustically Vaporized Droplet

Science.gov (United States)

Siddiqui, Junaid; Qamar, Adnan; Samtaney, Ravi

2015-11-01

Acoustic droplet vaporization (ADV) is a phase transition phenomena of a superheat liquid (Dodecafluoropentane, C5F12) droplet to a gaseous bubble, instigated by a high-intensity acoustic pulse. This approach was first studied in imaging applications, and applicable in several therapeutic areas such as gas embolotherapy, thrombus dissolution, and drug delivery. High-speed imaging and theoretical modeling of ADV has elucidated several physical aspects, ranging from bubble nucleation to its subsequent growth. Surface instabilities are known to exist and considered responsible for evolving bubble shapes (non-spherical growth, bubble splitting and bubble droplet encapsulation). We present a linear stability analysis of the dynamically evolving interfaces of an acoustically vaporized micro-droplet (liquid A) in an infinite pool of a second liquid (liquid B). We propose a thermal ADV model for the base state. The linear analysis utilizes spherical harmonics (Ynm, of degree m and order n) and under various physical assumptions results in a time-dependent ODE of the perturbed interface amplitudes (one at the vapor/liquid A interface and the other at the liquid A/liquid B interface). The perturbation amplitudes are found to grow exponentially and do not depend on m. Supported by KAUST Baseline Research Funds.

Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

Science.gov (United States)

Akasaka, Ryo

This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

Toward a Monte Carlo program for simulating vapor-liquid phase equilibria from first principles

Energy Technology Data Exchange (ETDEWEB)

McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; Vandevondele, J; Sprik, M; Hutter, J; Mohamed, F; Krack, M; Parrinello, M

2004-10-20

Efficient Monte Carlo algorithms are combined with the Quickstep energy routines of CP2K to develop a program that allows for Monte Carlo simulations in the canonical, isobaric-isothermal, and Gibbs ensembles using a first principles description of the physical system. Configurational-bias Monte Carlo techniques and pre-biasing using an inexpensive approximate potential are employed to increase the sampling efficiency and to reduce the frequency of expensive ab initio energy evaluations. The new Monte Carlo program has been validated through extensive comparison with molecular dynamics simulations using the programs CPMD and CP2K. Preliminary results for the vapor-liquid coexistence properties (T = 473 K) of water using the Becke-Lee-Yang-Parr exchange and correlation energy functionals, a triple-zeta valence basis set augmented with two sets of d-type or p-type polarization functions, and Goedecker-Teter-Hutter pseudopotentials are presented. The preliminary results indicate that this description of water leads to an underestimation of the saturated liquid density and heat of vaporization and, correspondingly, an overestimation of the saturated vapor pressure.

Feasibility of refreezing human spermatozoa through the technique of liquid nitrogen vapor

Directory of Open Access Journals (Sweden)

Sidney Verza Jr

2004-12-01

Full Text Available OBJECTIVE: To assess the feasibility of refreezing human semen using the technique of liquid nitrogen vapor with static phases. MATERIALS AND METHODS: Twenty samples from 16 subjects who required disposal of their cryopreserved semen were thawed, corresponding to 6 cancer patients and 10 participants in the assisted reproduction (AR program. Samples were refrozen using the technique of liquid nitrogen vapor with static phases, identical to the one used for the initial freezing, and thawed again after 72 hours. We assessed the concentration of motile spermatozoa, total and progressive percent motility and spermatic vitality, according to criteria of the World Health Organization (WHO, as well as spermatic morphology according to the strict Kruger criterion, after the first and after the second thawing. RESULTS: We observed a significant decrease in all the parameters evaluated between the first and the second thawing. Median values for the concentration of motile spermatozoa decreased from 2.0x10(6/mL to 0.1x10(6/mL (p < 0.01; total percent motility from 42% to 22.5% (p < 0.01; progressive percent motility from 34% to 9.5% (p < 0.01; vitality from 45% to 20% (p < 0.01; and morphology from 5% to 5% (p = 0.03. There was no significant difference in the spermatic parameters between the cancer and assisted reproduction groups, both after the first and after the second thawing. We observed that in 100% of cases there was retrieval of motile spermatozoa after the second thawing. CONCLUSIONS: Refreezing of human semen by the technique of liquid nitrogen vapor allows the retrieval of viable spermatozoa after thawing.

Indirect heating of natural gas using vapor chambers; Aquecimento indireto de gas natural com uso de camaras de vapor

Energy Technology Data Exchange (ETDEWEB)

Milanez, Fernando H; Mantellil, Marcia H.B.; Borges, Thomaz P.F. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica; Landa, Henrique G. de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

2005-07-01

Operation safety and reliability are major guidelines in the design of city-gate units. Conventional natural gas heaters operate by a indirect mechanism, where liquid water is used to transfer heat by natural convection between the combustion chamber and the natural gas coil. In this work, the concept of vapor chamber is evaluated as an indirect gas heater. In a vapor chamber, liquid water is in contact with the heat source, and vaporizes. The vapor condenses in contact with the heat sink. A reduced scale model was built and tested in order to compare these two heating concepts where the combustion chamber was replaced by electrical cartridge heaters. This engineering model can operate either as a conventional heater or as a vapor chamber. The comparison between the concepts was done by inducing a controlled power to the cartridges and by measuring the resulting temperature distributions. In the novel design, the heat exchanger efficiency increases, and the thermal inertia decreases, compared to the conventional system. The new sealed concept of the chamber prevents water evaporation losses. (author)

Vaporization of the prototypical ionic liquid BMImNTf₂ under equilibrium conditions: a multitechnique study.

Science.gov (United States)

Brunetti, Bruno; Ciccioli, Andrea; Gigli, Guido; Lapi, Andrea; Misceo, Nicolaemanuele; Tanzi, Luana; Vecchio Ciprioti, Stefano

2014-08-07

The vaporization behaviour and thermodynamics of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) were studied by combining the Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS) techniques. KEML studies were carried out in a large temperature range (398-567) K by using effusion orifices with 0.3, 1, and 3 mm diameters. The vapor pressures so measured revealed no kinetically hindered vaporization effects and provided second-law vaporization enthalpies at the mean experimental temperatures in close agreement with literature. By exploiting the large temperature range covered, the heat capacity change associated with vaporization was estimated, resulting in a value of -66.8 J K(-1) mol(-1), much lower than that predicted from calorimetric measurements on the liquid phase and theoretical calculations on the gas phase. The conversion of the high temperature vaporization enthalpy to 298 K was discussed and the value Δ(l)(g)H(m)(298 K) = (128.6 ± 1.3) kJ mol(-1) assessed on the basis of data from literature and present work. Vapor pressure data were also processed by the third-law procedure using different estimations for the auxiliary thermal functions, and a Δ(l)(g)H(m)(298 K) consistent with the assessed value was obtained, although the overall agreement is sensitive to the accuracy of heat capacity data. KEMS measurements were carried out in the lower temperature range (393-467) K and showed that the largely prevailing ion species is BMIm(+), supporting the common view of BMImNTf2 vaporizing as individual, neutral ion pairs also under equilibrium conditions. By monitoring the mass spectrometric signal of this ion as a function of temperature, a second-law Δ(l)(g)H(m)(298 K) of 129.4 ± 7.3 kJ mol(-1) was obtained, well consistent with KEML and literature results. Finally, by combining KEML and KEMS measurements, the electron impact ionization cross section of BMIm(+) was estimated.

Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

KAUST Repository

Vakarelski, Ivan Uriev

2016-09-08

The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

Leidenfrost Vapor Layers Reduce Drag without the Crisis in High Viscosity Liquids

KAUST Repository

Vakarelski, Ivan Uriev; Berry, Joseph D.; Chan, Derek Y C; Thoroddsen, Sigurdur T

2016-01-01

The drag coefficient CD of a solid smooth sphere moving in a fluid is known to be only a function of the Reynolds number Re and diminishes rapidly at the drag crisis around Re∼3×105. A Leidenfrost vapor layer on a hot sphere surface can trigger the onset of the drag crisis at a lower Re. By using a range of high viscosity perfluorocarbon liquids, we show that the drag reduction effect can occur over a wide range of Re, from as low as ∼600 to 105. The Navier slip model with a viscosity dependent slip length can fit the observed drag reduction and wake shape. © 2016 American Physical Society.

VOC composition of current motor vehicle fuels and vapors, and collinearity analyses for receptor modeling.

Science.gov (United States)

Chin, Jo-Yu; Batterman, Stuart A

2012-03-01

The formulation of motor vehicle fuels can alter the magnitude and composition of evaporative and exhaust emissions occurring throughout the fuel cycle. Information regarding the volatile organic compound (VOC) composition of motor fuels other than gasoline is scarce, especially for bioethanol and biodiesel blends. This study examines the liquid and vapor (headspace) composition of four contemporary and commercially available fuels: gasoline (gasoline), ultra-low sulfur diesel (ULSD), and B20 (20% soy-biodiesel and 80% ULSD). The composition of gasoline and E85 in both neat fuel and headspace vapor was dominated by aromatics and n-heptane. Despite its low gasoline content, E85 vapor contained higher concentrations of several VOCs than those in gasoline vapor, likely due to adjustments in its formulation. Temperature changes produced greater changes in the partial pressures of 17 VOCs in E85 than in gasoline, and large shifts in the VOC composition. B20 and ULSD were dominated by C(9) to C(16)n-alkanes and low levels of the aromatics, and the two fuels had similar headspace vapor composition and concentrations. While the headspace composition predicted using vapor-liquid equilibrium theory was closely correlated to measurements, E85 vapor concentrations were underpredicted. Based on variance decomposition analyses, gasoline and diesel fuels and their vapors VOC were distinct, but B20 and ULSD fuels and vapors were highly collinear. These results can be used to estimate fuel related emissions and exposures, particularly in receptor models that apportion emission sources, and the collinearity analysis suggests that gasoline- and diesel-related emissions can be distinguished. Copyright © 2011 Elsevier Ltd. All rights reserved.

Correlation of the vapor pressure isotope effect with molecular force fields in the liquid state

International Nuclear Information System (INIS)

Pollin, J.S.; Ishida, T.

1976-07-01

The present work is concerned with the development and application of a new model for condensed phase interactions with which the vapor pressure isotope effect (vpie) may be related to molecular forces and structure. The model considers the condensed phase as being represented by a cluster of regularly arranged molecules consisting of a central molecule and a variable number of molecules in the first coordination shell. The methods of normal coordinate analysis are used to determine the modes of vibration of the condensed phase cluster from which, in turn, the isotopic reduced partition function can be calculated. Using the medium cluster model, the observed vpie for a series of methane isotopes has been successfully reproduced with better agreement with experiment than has been possible using the simple cell model. We conclude, however, that insofar as the medium cluster model provides a reasonable picture of the liquid state, the vpie is not sufficiently sensitive to molecular orientation to permit an experimental determination of intermolecular configuration in the condensed phase through measurement of isotopic pressure ratios. The virtual independence of vapor pressure isotope effects on molecular orientation at large cluster sizes is a demonstration of the general acceptability of the cell model assumptions for vpie calculations

Predicting the heat of vaporization of iron at high temperatures using time-resolved laser-induced incandescence and Bayesian model selection

Science.gov (United States)

Sipkens, Timothy A.; Hadwin, Paul J.; Grauer, Samuel J.; Daun, Kyle J.

2018-03-01

Competing theories have been proposed to account for how the latent heat of vaporization of liquid iron varies with temperature, but experimental confirmation remains elusive, particularly at high temperatures. We propose time-resolved laser-induced incandescence measurements on iron nanoparticles combined with Bayesian model plausibility, as a novel method for evaluating these relationships. Our approach scores the explanatory power of candidate models, accounting for parameter uncertainty, model complexity, measurement noise, and goodness-of-fit. The approach is first validated with simulated data and then applied to experimental data for iron nanoparticles in argon. Our results justify the use of Román's equation to account for the temperature dependence of the latent heat of vaporization of liquid iron.

Rotating biological contactors: the Canadian experience

Energy Technology Data Exchange (ETDEWEB)

Cuenca, Manuel A [Ryerson Polytechnical Univ., Toronto, ON (Canada). Chemical Engineering Dept.; Smith, Tom [CMS Rotordisk Inc., Concord, ON (Canada); Vianna, Arlinda C [Servico Nacional de Aprendizagem Industrial (SENAI), Salvador, BA (Brazil)

1994-12-31

In fifteen years, Rotating Biological Contactors (RBC) have become one of the most attractive technologies for secondary wastewater treatment. The present work is a review of the evolution of RBC technology in the last twenty years. In addition, the status of the technology in Canada is described, emphasizing industrial facilities and landfill leachate treatment. An enumeration of the most relevant development areas is included. (author). 34 refs., 3 figs., 7 tabs.

Rotating biological contactors: the Canadian experience

Energy Technology Data Exchange (ETDEWEB)

Cuenca, Manuel A. [Ryerson Polytechnical Univ., Toronto, ON (Canada). Chemical Engineering Dept.; Smith, Tom [CMS Rotordisk Inc., Concord, ON (Canada); Vianna, Arlinda C. [Servico Nacional de Aprendizagem Industrial (SENAI), Salvador, BA (Brazil)

1993-12-31

In fifteen years, Rotating Biological Contactors (RBC) have become one of the most attractive technologies for secondary wastewater treatment. The present work is a review of the evolution of RBC technology in the last twenty years. In addition, the status of the technology in Canada is described, emphasizing industrial facilities and landfill leachate treatment. An enumeration of the most relevant development areas is included. (author). 34 refs., 3 figs., 7 tabs.

Indirect Determination of Vapor Pressures by Capillary Gas-Liquid Chromatography: Analysis of the Reference Vapor-Pressure Data and Their Treatment

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Koutek, Bohumír; Fulem, M.; Hoskovec, Michal

2012-01-01

Roč. 57, č. 5 (2012), s. 1349-1368 ISSN 0021-9568 R&D Projects: GA ČR GA203/09/1327 Institutional research plan: CEZ:AV0Z40550506 Keywords : vapor pressures * capillary gas–liquid chromatography * reference data * relative retention time Subject RIV: CC - Organic Chemistry Impact factor: 2.004, year: 2012

Vapor-liquid phase behavior of a size-asymmetric model of ionic fluids confined in a disordered matrix: The collective-variables-based approach

Science.gov (United States)

Patsahan, O. V.; Patsahan, T. M.; Holovko, M. F.

2018-02-01

We develop a theory based on the method of collective variables to study the vapor-liquid equilibrium of asymmetric ionic fluids confined in a disordered porous matrix. The approach allows us to formulate the perturbation theory using an extension of the scaled particle theory for a description of a reference system presented as a two-component hard-sphere fluid confined in a hard-sphere matrix. Treating an ionic fluid as a size- and charge-asymmetric primitive model (PM) we derive an explicit expression for the relevant chemical potential of a confined ionic system which takes into account the third-order correlations between ions. Using this expression, the phase diagrams for a size-asymmetric PM are calculated for different matrix porosities as well as for different sizes of matrix and fluid particles. It is observed that general trends of the coexistence curves with the matrix porosity are similar to those of simple fluids under disordered confinement, i.e., the coexistence region gets narrower with a decrease of porosity and, simultaneously, the reduced critical temperature Tc* and the critical density ρi,c * become lower. At the same time, our results suggest that an increase in size asymmetry of oppositely charged ions considerably affects the vapor-liquid diagrams leading to a faster decrease of Tc* and ρi,c * and even to a disappearance of the phase transition, especially for the case of small matrix particles.

A study on the development of advanced models to predict the critical heat flux for water and liquid metals

International Nuclear Information System (INIS)

Lee, Yong Bum

1994-02-01

The critical heat flux (CHF) phenomenon in the two-phase convective flows has been an important issue in the fields of design and safety analysis of light water reactor (LWR) as well as sodium cooled liquid metal fast breeder reactor (LMFBR). Especially in the LWR application many physical aspects of the CHF phenomenon are understood and reliable correlations and mechanistic models to predict the CHF condition have been proposed. However, there are few correlations and models which are applicable to liquid metals. Compared with water, liquid metals show a divergent picture for boiling pattern. Therefore, the CHF conditions obtained from investigations with water cannot be applied to liquid metals. In this work a mechanistic model to predict the CHF of water and a correlation for liquid metals are developed. First, a mechanistic model to predict the CHF in flow boiling at low quality was developed based on the liquid sublayer dryout mechanism. In this approach the CHF is assumed to occur when a vapor blanket isolates the liquid sublayer from bulk liquid and then the liquid entering the sublayer falls short of balancing the rate of sublayer dryout by vaporization. Therefore, the vapor blanket velocity is the key parameter. In this work the vapor blanket velocity is theoretically determined based on mass, energy, and momentum balance and finally the mechanistic model to predict the CHF in flow boiling at low quality is developed. The accuracy of the present model is evaluated by comparing model predictions with the experimental data and tabular data of look-up tables. The predictions of the present model agree well with extensive CHF data. In the latter part a correlation to predict the CHF for liquid metals is developed based on the flow excursion mechanism. By using Baroczy two-phase frictional pressure drop correlation and Ledinegg instability criterion, the relationship between the CHF of liquid metals and the principal parameters is derived and finally the

Thermophysical properties of hydrogen along the liquid-vapor coexistence

Science.gov (United States)

Osman, S. M.; Sulaiman, N.; Bahaa Khedr, M.

2016-05-01

We present Theoretical Calculations for the Liquid-Vapor Coexistence (LVC) curve of fluid Hydrogen within the first order perturbation theory with a suitable first order quantum correction to the free energy. In the present equation of state, we incorporate the dimerization of H2 molecule by treating the fluid as a hard convex body fluid. The thermophysical properties of fluid H2 along the LVC curve, including the pressure-temperature dependence, density-temperature asymmetry, volume expansivity, entropy and enthalpy, are calculated and compared with computer simulation and empirical results.

High flux diode packaging using passive microscale liquid-vapor phase change

Science.gov (United States)

Bandhauer, Todd; Deri, Robert J.; Elmer, John W.; Kotovsky, Jack; Patra, Susant

2017-09-19

A laser diode package includes a heat pipe having a fluid chamber enclosed in part by a heat exchange wall for containing a fluid. Wicking channels in the fluid chamber is adapted to wick a liquid phase of the fluid from a condensing section of the heat pipe to an evaporating section of the heat exchanger, and a laser diode is connected to the heat exchange wall at the evaporating section of the heat exchanger so that heat produced by the laser diode is removed isothermally from the evaporating section to the condensing section by a liquid-to-vapor phase change of the fluid.

Muonium formation and the 'missing fraction' in vapors

International Nuclear Information System (INIS)

Fleming, D.G.; Arseneau, D.J.; Garner, D.M.; Senba, M.; Mikula, R.J.

1983-06-01

The vapor phase fractional polarizations of positive muons thermalizing as the muonium atom (Psub(M)) and in diamagnetic environments (Psub(D)) has been measured in H 2 O, CH 3 OH, C 6 H 14 , C 6 H 12 , CCl 4 , CHCl 3 , CH 2 Cl 2 and TMS, in order to compare with the corresponding fractions measured in the condensed phases. There is a marked contrast in every case, with the vapor phase results being largely understandable in terms of a charge exchange/hot atom model. Unlike the situation in the corresponding liquids, there is no permanent lost fraction in the vapor phase in the limit of even moderately high pressures (approximately 1 atm); at lower pressures, depolarization is due to hyperfine mixing and is believed to be well understood. For vapor phase CH 3 OH, C 6 H 14 , C 6 H 12 , and TMS the relative fractions are found to be pressure dependent, suggesting the importance of termolecular hot atom (or ion) reactions in the slowing-down process. For vapor phase H 2 O and the chloromethanes, the relative fractions are pressure independent. For CCl 4 , Psub(M) = Psub(D) approximately 0.5 in the vapor phase vs. Psub(D) = 1.0 in the liquid phase; fast thermal reactions of Mu likely contribute significantly to this difference in the liquid phase. For H 2 O, Psub(M) approximately 0.9 and Psub(D) approximately 0.1 in the vapor phase vs. Psub(D) approximately 0.6 and Psub(M) approximately 0.2 in the liquid phase. Water appears to be the one unequivocal case where the basic charge exchange/hot atom model is inappropriate in the condensed phase, suggesting, therefore, that radiation-induced 'spur' effects play a major role

The removal of dinitrochlorobenzene from industrial residuals by liquid-liquid extraction with chemical reaction

Directory of Open Access Journals (Sweden)

G. C. M. Ferreira

2007-09-01

Full Text Available Nitrochlorobenzenes (NCBs are very important in the chemical industry since they have been used as raw material for the manufacture of crop protection products, as active ingredients in the pharmaceutical industry, as pigments and as antioxidants as well as for other uses. In industrial processes, NCBs are produced by monochlorobenzene (MCB nitration reactions and one of the main residuals formed is dinitrochlorobenzene (DNCB, which is mainly composed of the isomer 2,4DNCB. This subproduct, although of commercial interest when in its pure state, is generally incinerated due to the high costs of recovery treatment and purification. The objective of this study is to present an alternative to the treatment of industrial residuals containing DNCB. The technique consists of converting DNCB into sodium dinitrophenolate, which is very soluble in water and is also easy to reuse. For this purpose, liquid-liquid extraction with chemical reaction (alkaline hydrolysis with a rotating disc contactor (RDC is used. Experimental data on MCB nitration reactions as well as alkaline hydrolysis using a rotating disc contactor are presented.

Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

Energy Technology Data Exchange (ETDEWEB)

Mahdi, Taha; Ahmad, Arshad; Ripin, Adnan Nasef; Mohamed, Mahmoud [Universiti Teknologi Malaysia, Johor Bahru (Malaysia)

2014-05-15

A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100-400W/cm{sup 2} and three frequencies ranging from 25-68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm{sup 2} and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress.

Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

International Nuclear Information System (INIS)

Mahdi, Taha; Ahmad, Arshad; Ripin, Adnan Nasef; Mohamed, Mahmoud

2014-01-01

A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100-400W/cm 2 and three frequencies ranging from 25-68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm 2 and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress

Modeling the fine fragmentation following the triggering stage of a vapor explosion

International Nuclear Information System (INIS)

Darbord, I.

1997-01-01

In the frame of PWR severe accidents, where the core melt, this thesis studies one of the stages of an FCI (fuel coolant interaction) or vapor explosion. An FCI is a rapid evaporation of a coolant when it comes into contact with a hot liquid. More precisely, the subject of this study is the triggering stage of the FCI, when a fuel drop of diameter around one centimeter breaks up into many fragments, diameter of which is around a hundred micrometers. The model describes the cyclic collapse and growth of a vapor bubble around the fuel droplet and its fragmentation. The main features of the model are: - the destabilization of the film or the vapor bubble due to the growth of Rayleigh-Taylor instabilities (those form coolant jets that contact the fuel surface); - The mechanisms of fragmentation, following the contacts (in the case of entrapment of a certain amount of coolant in the fuel, the entrapped coolant evaporates violently after it has been heated to the homogeneous nucleation temperature); - the transient heat transfer from the fragments to the coolant and the elevated vapor production, which leads to an important expansion of the bubble (about this point, the cooling of the fragments has been described by a transient heat transfer coefficient linked to nucleate boiling). The results of the model show good agreement with experimental data. (Author)

Study on the effect of subcooling on vapor film collapse on high temperature particle surface

International Nuclear Information System (INIS)

Abe, Yutaka; Tochio, Daisuke; Yanagida, Hiroshi

2000-01-01

Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface is needed to be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcooling condition is qualitatively different from the vapor film collapse behavior in high subcooling condition. In case of vapor film collapse by pressure pulse, homogeneous vapor generation occurred all over the surface of steel particle in low subcooling condition. On the other hand, heterogeneous vapor generation was observed for higher subcooling condition. In case of vapor film collapse spontaneously, fluctuation of the gas-liquid interface after quenching propagated from bottom to top of the steel particle heterogeneously in low subcooling condition. On the other hand, simultaneous vapor generation occurred for higher subcooling condition. And the time transient of pressure, particle surface temperature, water temperature and visual information were simultaneously measured in the vapor film collapse experiment by external pressure pulse. Film thickness was estimated by visual data processing technique with the pictures taken by the high-speed video camera. Temperature and heat flux at the vapor-liquid interface were estimated by solving the heat condition equation with the measured pressure, liquid temperature and vapor film thickness as boundary conditions. Movement of the vapor-liquid interface were estimated with the PIV technique with the visual observation

Ozone mass transfer behaviors on physical and chemical absorption for hollow fiber membrane contactors.

Science.gov (United States)

Zhang, Yong; Li, Kuiling; Wang, Jun; Hou, Deyin; Liu, Huijuan

2017-09-01

To understand the mass transfer behaviors in hollow fiber membrane contactors, ozone fluxes affected by various conditions and membranes were investigated. For physical absorption, mass transfer rate increased with liquid velocity and the ozone concentration in the gas. Gas flow rate was little affected when the velocity was larger than the critical value, which was 6.1 × 10 -3 m/s in this study. For chemical absorption, the flux was determined by the reaction rate between ozone and the absorbent. Therefore, concentration, species, and pH affected the mass transfer process markedly. For different absorbents, the order of mass transfer rate was the same as the reaction rate constant, which was phenol, sodium nitrite, hydrogen peroxide, and oxalate. Five hydrophobic membranes with various properties were employed and the mass transfer behavior can be described by the Graetz-Lévèque equation for the physical absorption process. The results showed the process was controlled by liquid film and the gas phase conditions, and membrane properties did not affect the ozone flux. For the chemical absorption, gas film, membrane and liquid film affected the mass transfer together, and none of them were negligible.

Prediction of the liquid-vapor equilibrium pressure using the quasi-Gaussian entropy theory

NARCIS (Netherlands)

Amadei, A; Roccatano, D; Apol, M.E F; Berendsen, H.J.C.; Di Nola, A.

1996-01-01

We derived a method to evaluate the liquid-vapor equilibrium pressure, with high accuracy over a large range of temperature, using the quasi-Gaussian entropy theory. The final expression that we obtain for the equilibrium pressure as a function of the temperature can be considered as a very accurate

Evaluation of E-Cigarette Liquid Vapor and Mainstream Cigarette Smoke after Direct Exposure of Primary Human Bronchial Epithelial Cells

Directory of Open Access Journals (Sweden)

Stefanie Scheffler

2015-04-01

Full Text Available E-cigarettes are emerging products, often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5–8 times lower and the oxidative stress levels 4.5–5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.

Evaluation of E-cigarette liquid vapor and mainstream cigarette smoke after direct exposure of primary human bronchial epithelial cells.

Science.gov (United States)

Scheffler, Stefanie; Dieken, Hauke; Krischenowski, Olaf; Förster, Christine; Branscheid, Detlev; Aufderheide, Michaela

2015-04-08

E-cigarettes are emerging products, often described as "reduced-risk" nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5-8 times lower and the oxidative stress levels 4.5-5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

Science.gov (United States)

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Liquid phase stabilization versus bubble formation at a nanoscale curved interface

Science.gov (United States)

Schiffbauer, Jarrod; Luo, Tengfei

2018-03-01

We investigate the nature of vapor bubble formation near a nanoscale-curved convex liquid-solid interface using two models: an equilibrium Gibbs model for homogenous nucleation, and a nonequilibrium dynamic van der Waals-diffuse-interface model for phase change in an initially cool liquid. Vapor bubble formation is shown to occur for sufficiently large radius of curvature and is suppressed for smaller radii. Solid-fluid interactions are accounted for and it is shown that liquid-vapor interfacial energy, and hence Laplace pressure, has limited influence over bubble formation. The dominant factor is the energetic cost of creating the solid-vapor interface from the existing solid-liquid interface, as demonstrated via both equilibrium and nonequilibrium arguments.

Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

Directory of Open Access Journals (Sweden)

Shiina Tatsuo

2016-01-01

Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

Structure–property relationships in ionic liquids: Influence of branched and cyclic groups on vaporization enthalpies of imidazolium-based ILs

International Nuclear Information System (INIS)

Zaitsau, Dzmitry H.; Varfolomeev, Mikhail A.; Verevkin, Sergey P.; Stanton, Alexander D.; Hindman, Michelle S.; Bara, Jason E.

2016-01-01

Highlights: • Ionic liquids [Rmim][NTf_2] with iso-alkyl and cyclic substituents were synthesized. • Vaporization enthalpies were measured using quartz-crystal microbalance. • Data consistency was tested by comparison with the homomorph compounds. • Vaporization enthalpies of branched ILs are generally on the same level as for linear. • These findings are useful for the quick estimation of vaporization enthalpies. - Abstract: Ionic liquids (ILs) with branched and cyclic substituents are seldom studied in the literature, and as such there are little to no data characterizing their thermophysical properties. ILs with branched and cyclic substituents are just as convenient to synthesize and study as their counterparts with linear substituents, but the effects of these substituents on IL properties are not yet well-defined due to the preference for linear substituents. Standard molar vaporization enthalpies of six imidazolium based ionic liquids [Rmim][NTf_2] with iso-alkyl and cyclic substituents (R = iso-propyl, iso-butyl, sec-butyl, methylcyclopropyl, cyclopentyl and methylcyclohexyl) were derived from quartz-crystal microbalance (QCM) method. Enthalpies of vaporization measured at elevated temperatures have been adjusted to the reference temperature 298 K and tested for consistency by comparison with the homomorphy alkane, alkylbenzenes and alkyl-imidazoles. It was found that vaporization enthalpies of ILs with the iso-alkyl and cyclic groups are generally on the same level within (±2 to 3) kJ · mol"−"1 significantly compared to the analogous ILs with the imidazolium cation substituted with the linear alkyl substituents of the same chain length. These findings are useful for the quick estimation of vaporization enthalpies of various substituted IL cations (e.g. pyrrolidinium, ammonium, pyridinium, etc.).

Vapor-Liquid Equilibrium in the Mixture 1,1-Difluoroethane C2H4F2 + C4H8 2-Methylpropene (EVLM1131, LB5730_E)

Science.gov (United States)

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture 1,1-Difluoroethane C2H4F2 + C4H8 2-Methylpropene (EVLM1131, LB5730_E)' providing data from direct measurement of pressure and mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Ion clustering in aqueous salt solutions near the liquid/vapor interface

Directory of Open Access Journals (Sweden)

J.D. Smith

2016-03-01

Full Text Available Molecular dynamics simulations of aqueous NaCl, KCl, NaI, and KI solutions are used to study the effects of salts on the properties of the liquid/vapor interface. The simulations use the models which include both charge transfer and polarization effects. Pairing and the formation of larger ion clusters occurs both in the bulk and surface region, with a decreased tendency to form larger clusters near the interface. An analysis of the roughness of the surface reveals that the chloride salts, which have less tendency to be near the surface, have a roughness that is less than pure water, while the iodide salts, which have a greater surface affinity, have a larger roughness. This suggests that ions away from the surface and ions near the surface affect the interface in opposite ways.

Prediction of high pressure vapor-liquid equilibria with mixing rule using ASOG group contribution method

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K.; Kojima, K.; Kurihara, K.

1985-02-01

To develop a widely applicable method for predicting high-pressure vapor-liquid equilibria by the equation of state, a mixing rule is proposed in which mixture energy parameter ''..cap alpha..'' of theSoave-RedlichKwong, Peng-Robinson, and Martin cubic equations of state is expressed by using the ASOG group contribution method. The group pair parameters are then determined for 14 group pairs constituted by six groups, i.e. CH/sub 4/, CH/sub 3/, CH/sub 2/, N/sub 2/, H/sub 2/, and CO/sub 2/ groups. By using the group pair parameters determined, high-pressure vapor-liquid equilibria are predicted with good accuracy for binary and ternary systems constituted by n-paraffins, nitrogen, hydrogen, and carbon dioxide in the temperature range of 100 - 450K.

Application of annular centrifugal contactors in the hot test of the improved total partitioning process for high level liquid waste.

Science.gov (United States)

Duan, Wuhua; Chen, Jing; Wang, Jianchen; Wang, Shuwei; Feng, Xiaogui; Wang, Xinghai; Li, Shaowei; Xu, Chao

2014-08-15

High level liquid waste (HLLW) produced from the reprocessing of the spent nuclear fuel still contains moderate amounts of uranium, transuranium (TRU) actinides, (90)Sr, (137)Cs, etc., and thus constitutes a permanent hazard to the environment. The partitioning and transmutation (P&T) strategy has increasingly attracted interest for the safe treatment and disposal of HLLW, in which the partitioning of HLLW is one of the critical technical issues. An improved total partitioning process, including a TRPO (tri-alkylphosphine oxide) process for the removal of actinides, a CESE (crown ether strontium extraction) process for the removal of Sr, and a CECE (calixcrown ether cesium extraction) process for the removal of Cs, has been developed to treat Chinese HLLW. A 160-hour hot test of the improved total partitioning process was carried out using 72-stage 10-mm-dia annular centrifugal contactors (ACCs) and genuine HLLW. The hot test results showed that the average DFs of total α activity, Sr and Cs were 3.57 × 10(3), 2.25 × 10(4) and 1.68 × 10(4) after the hot test reached equilibrium, respectively. During the hot test, 72-stage 10-mm-dia ACCs worked stable, continuously with no stage failing or interruption of the operation. Copyright © 2014 Elsevier B.V. All rights reserved.

Simple liquid models with corrected dielectric constants

Science.gov (United States)

Fennell, Christopher J.; Li, Libo; Dill, Ken A.

2012-01-01

Molecular simulations often use explicit-solvent models. Sometimes explicit-solvent models can give inaccurate values for basic liquid properties, such as the density, heat capacity, and permittivity, as well as inaccurate values for molecular transfer free energies. Such errors have motivated the development of more complex solvents, such as polarizable models. We describe an alternative here. We give new fixed-charge models of solvents for molecular simulations – water, carbon tetrachloride, chloroform and dichloromethane. Normally, such solvent models are parameterized to agree with experimental values of the neat liquid density and enthalpy of vaporization. Here, in addition to those properties, our parameters are chosen to give the correct dielectric constant. We find that these new parameterizations also happen to give better values for other properties, such as the self-diffusion coefficient. We believe that parameterizing fixed-charge solvent models to fit experimental dielectric constants may provide better and more efficient ways to treat solvents in computer simulations. PMID:22397577

On the Bias in the Danckwerts’ Plot Method for the Determination of the Gas–Liquid Mass-Transfer Coefficient and Interfacial Area

Directory of Open Access Journals (Sweden)

German E. Cortes Garcia

2018-02-01

Full Text Available The Danckwerts’ plot method is a commonly used graphical technique to independently determine the interfacial area and mass-transfer coefficient in gas–liquid contactors. The method was derived in 1963 when computational capabilities were limited and intensified process equipment did not exist. A numerical analysis of the underlying assumptions of the method in this paper has shown a bias in the technique, especially for situations where mass-transfer rates are intensified, or where there is limited liquid holdup in the bulk compared to the film layers. In fact, systematic errors of up to 50% in the interfacial area, and as high as 90% in the mass-transfer coefficients, can be expected for modern, intensified gas–liquid contactors, even within the commonly accepted validity limits of a pseudo-first-order reaction and Hatta numbers in the range of 0.3 < Ha < 3. Given the current computational capabilities and the intensified mass-transfer rates in modern gas–liquid contactors, it is therefore imperative that the equations for reaction and diffusion in the liquid films are numerically solved and subsequently used to fit the interfacial area and mass-transfer coefficient to experimental data, which would traditionally be used in the graphical Danckwerts’ method.

COMPARISON OF THE OCTANOL-AIR PARTITION COEFFICIENT AND LIQUID-PHASE VAPOR PRESSURE AS DESCRIPTORS FOR PARTICLE/GAS PARTITIONING USING LABORATORY AND FIELD DATA FOR PCBS AND PCNS

Science.gov (United States)

The conventional Junge-Pankow adsorption model uses the sub-cooled liquid vapor pressure (pLo) as a correlation parameter for gas/particle interactions. An alternative is the octanol-air partition coefficient (Koa) absorption model. Log-log plots of the particle-gas partition c...

Vapor-liquid equilibrium ratio of trace furfural in water+1-butanol system; Mizu+1-butanorukei ni okeru biryo no furufuraru no kieki heikohi

Energy Technology Data Exchange (ETDEWEB)

Ikari, A.; Hatate, Y.; Aikou, R. [Kagoshima Univ. (Japan). Faculty of Engineering

1997-11-01

Vapor-liquid equilibria of a water + 1-butanol system containing a trace amount of furfural were measured at atmospheric pressure by use of a Iino-type still for systems of limited miscibility. Vapor-liquid compositions for the major components (water and 1-butanol) are shown to be nearly coincident with those of the binary system. In the partially miscible region, the vapor-liquid equilibrium ratios of the trace component (furfural) at bubble point were found to be 2.5 and 0.46. Consequently, the partition coefficient of the trace component between the two liquid phases is 5.4. The equilibrium ratio curve of the trace component is presented, in which the calculated curve within the partially miscible region is shown to be coincident with the experimental data. 5 refs., 3 figs., 1 tab.

Liquid--vapor isotope fractionation factors in argon--krypton binary mixtures

International Nuclear Information System (INIS)

Lee, M.W.; Neufeld, P.; Bigeleisen, J.

1977-01-01

An equilibrium isotope effect has been studied as a continuous function of the potential field acting on the atom undergoing isotopic exchange. This has been accomplished through a study of the liquid vapor isotope fractionation factors for both, 36 Ar/ 40 Ar and 80 Kr/ 84 Kr in a series of binary mixtures which span the range between the pure components at 117.5 0 K. The 36 Ar/ 40 Ar fractionation factor increases (linearly) from (lnα)2.49 x 10 -3 in pure liquid argon to 2.91 x 10 -3 in an infinitely dilute solution in liquid krypton. Conversely, the 80 Kr/ 84 Kr fractionation factor decreases (linearly) from (lnα)0.98 x 10 -3 in pure liquid krypton to 0.64 x 10 -3 in an infinetely dilute solution in pure liquid argon. The mean force constants 2 U>/sub c/ on both argon and krypton atoms in the mixtures are derived from the respective isotope fractionation factors.The mean force constants for argon and krypton as a function of composition have been calculated by a modified corresponding states theory which uses the pure liquids as input parameters. The discrepancy is 8 percent at X/sub Ar/ + O. A systematic set of calculations has been made of 2 U> (Ar) and 2 U> (Kr) as a function of composition using radial distribution functions generated by the Weeks--Chandler--Anderson perturbation theory

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium

Science.gov (United States)

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Thermally excited capillary waves at vapor/liquid interfaces of water-alcohol mixtures

International Nuclear Information System (INIS)

Vaknin, David; Bu Wei; Sung, Jaeho; Jeon, Yoonnam; Kim, Doseok

2009-01-01

The density profiles of liquid/vapor interfaces of water-alcohol (methanol, ethanol and propanol) mixtures were studied by surface-sensitive synchrotron x-ray scattering techniques. X-ray reflectivity and diffuse scattering measurements, from the pure and mixed liquids, were analyzed in the framework of capillary wave theory to address the characteristic length scales of the intrinsic roughness and the shortest capillary wavelength (alternatively, the upper wavevector cutoff in capillary wave theory). Our results establish that the intrinsic roughness is dominated by average interatomic distances. The extracted effective upper wavevector cutoff indicates capillary wave theory breaks down at distances of the order of bulk correlation lengths.

Simulation of water vapor condensation on LOX droplet surface using liquid nitrogen

Science.gov (United States)

Powell, Eugene A.

1988-01-01

The formation of ice or water layers on liquid oxygen (LOX) droplets in the Space Shuttle Main Engine (SSME) environment was investigated. Formulation of such ice/water layers is indicated by phase-equilibrium considerations under conditions of high partial pressure of water vapor (steam) and low LOX droplet temperature prevailing in the SSME preburner or main chamber. An experimental investigation was begun using liquid nitrogen as a LOX simulant. A monodisperse liquid nitrogen droplet generator was developed which uses an acoustic driver to force the stream of liquid emerging from a capillary tube to break up into a stream of regularly space uniformly sized spherical droplets. The atmospheric pressure liquid nitrogen in the droplet generator reservoir was cooled below its boiling point to prevent two phase flow from occurring in the capillary tube. An existing steam chamber was modified for injection of liquid nitrogen droplets into atmospheric pressure superheated steam. The droplets were imaged using a stroboscopic video system and a laser shadowgraphy system. Several tests were conducted in which liquid nitrogen droplets were injected into the steam chamber. Under conditions of periodic droplet formation, images of 600 micron diameter liquid nitrogen droplets were obtained with the stroboscopic video systems.

On The Validity of the Assumed PDF Method for Modeling Binary Mixing/Reaction of Evaporated Vapor in GAS/Liquid-Droplet Turbulent Shear Flow

Science.gov (United States)

Miller, R. S.; Bellan, J.

1997-01-01

An Investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is perfomed through both theroetical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer.

Reaction of water vapor with a clean liquid uranium surface

International Nuclear Information System (INIS)

Siekhaus, W.

1985-01-01

To study the reaction of water vapor with uranium, we have exposed clean liquid uranium surfaces to H 2 O under UHV conditions. We have measured the surface concentration of oxygen as a function of exposure, and determined the maximum attainable surface oxygen concentration X 0 /sup s/ as a function of temperature. We have used these measurements to estimate, close to the melting point, the solubility of oxygen (X 0 /sup b/, -4 ) and its surface segregation coefficient β/sup s/(> 10 3 ). 8 refs., 5 figs., 1 tab

Modeling of fuel vapor jet eruption induced by local droplet heating

KAUST Repository

Sim, Jaeheon

2014-01-10

The evaporation of a droplet by non-uniform heating is numerically investigated in order to understand the mechanism of the fuel-vapor jet eruption observed in the flame spread of a droplet array under microgravity condition. The phenomenon was believed to be mainly responsible for the enhanced flame spread rate through a droplet cloud at microgravity conditions. A modified Eulerian-Lagrangian method with a local phase change model is utilized to describe the interfacial dynamics between liquid droplet and surrounding air. It is found that the localized heating creates a temperature gradient along the droplet surface, induces the corresponding surface tension gradient, and thus develops an inner flow circulation commonly referred to as the Marangoni convection. Furthermore, the effect also produces a strong shear flow around the droplet surface, thereby pushing the fuel vapor toward the wake region of the droplet to form a vapor jet eruption. A parametric study clearly demonstrated that at realistic droplet combustion conditions the Marangoni effect is indeed responsible for the observed phenomena, in contrast to the results based on constant surface tension approximation

Vapor generation rate model for dispersed drop flow

International Nuclear Information System (INIS)

Unal, C.; Tuzla, K.; Cokmez-Tuzla, A.F.; Chen, J.C.

1991-01-01

A comparison of predictions of existing nonequilibrium post-CHF heat transfer models with the recently obtained rod bundle data has been performed. The models used the experimental conditions and wall temperatures to predict the heat flux and vapor temperatures at the location of interest. No existing model was able to reasonably predict the vapor superheat and the wall heat flux simultaneously. Most of the models, except Chen-Sundaram-Ozkaynak, failed to predict the wall heat flux, while all of the models could not predict the vapor superheat data or trends. A recently developed two-region heat transfer model, the Webb-Chen two-region model, did not give a reasonable prediction of the vapor generation rate in the far field of the CHF point. A new correlation was formulated to predict the vapor generation rate in convective dispersed droplet flow in terms of thermal-hydraulic parameters and thermodynamic properties. A comparison of predictions of the two-region heat transfer model, with the use of a presently developed correlation, with all the existing post-CHF data, including single-tube and rod bundle, showed significant improvements in predicting the vapor superheat and tube wall heat flux trends. (orig.)

Modeling UTLS water vapor: Transport/Chemistry interactions

International Nuclear Information System (INIS)

Gulstad, Line

2005-01-01

This thesis was initially meant to be a study on the impact on chemistry and climate from UTLS water vapor. However, the complexity of the UTLS water vapor and its recent changes turned out to be a challenge by it self. In the light of this, the overall motivation for the thesis became to study the processes controlling UTLS water vapor and its changes. Water vapor is the most important greenhouse gas, involved in important climate feedback loops. Thus, a good understanding of the chemical and dynamical behavior of water vapor in the atmosphere is crucial for understanding the climate changes in the last century. Additionally, parts of the work was motivated by the development of a coupled climate chemistry model based on the CAM3 model coupled with the Chemical Transport Model Oslo CTM2. The future work will be concentrated on the UTLS water vapor impact on chemistry and climate. We are currently studying long term trends in UTLS water vapor, focusing on identification of the different processes involved in the determination of such trends. The study is based on natural as well as anthropogenic climate forcings. The ongoing work on the development of a coupled climate chemistry model will continue within our group, in collaboration with Prof. Wei-Chyung Wang at the State University of New York, Albany. Valuable contacts with observational groups are established during the work on this thesis. These collaborations will be continued focusing on continuous model validation, as well as identification of trends and new features in UTLS water vapor, and other tracers in this region. (Author)

Membrane assisted liquid-liquid extraction of cerium

International Nuclear Information System (INIS)

Soldenhoff, K.M.

2000-02-01

Membrane assisted liquid-liquid extraction of cerium was investigated, with emphasis placed on the study of the reaction chemistry and the kinetics of non-dispersive solvent extraction and stripping with microporous membranes. A bulk liquid membrane process was developed for the purification of cerium(IV) from sulfate solutions containing other rare earth elements. The cerium process was studied in both a flat sheet contained liquid membrane configuration and with hollow fibre contactors. Di-2-ethylhexyl phosphoric acid (DEHPA) was identified as a suitable extractant for cerium(IV) from sulfuric acid solution, with due consideration of factors such as extraction ability, resistance to degradation, solvent selectivity and potential for sulfate transfer into a strip solution. A detailed study of the extraction of cerium(IV) with DEHPA defined the extraction reaction chemistry. The Ce/DEHPA/sulfate system was also investigated with a flat sheet bulk liquid membrane configuration, using both sulfuric and hydrochloric acid as receiver solutions. These tests identified that hydrophobic membranes provide better mass transfer for extraction and hydrophilic membranes are better for stripping. The presence of an impurity, mono 2-ethylhexyl phosphoric acid (MEHPA), was found to have a dramatic accelerating effect on the rate of the chemical extraction reaction. This was attributed to its higher interfacial activity and population compared to DEHPA, and the fact that MEHPA was also found to be an active carrier for cerium(IV). The mass transfer rate of membrane assisted extraction and stripping of cerium, using hydrophobic and hydrophilic microporous membranes, respectively, was investigated using a modified Lewis-type cell. It was quantitatively demonstrated that the extraction process was mainly controlled by membrane diffusion and the stripping process was controlled by the chemical reaction rate, with membrane diffusion becoming important at low distribution coefficients

Development of a new miniature short-residence-time annular centrifugal solvent extraction contactor for tests of process flowsheets in hot cells

International Nuclear Information System (INIS)

Lanoe, J.Y.; Rivalier, P.

2000-01-01

Researches undertaken on new nuclear fuel reprocessing extraction processes need tests of process flowsheets in hot cells. To this goal, a new miniature short residence-time annular centrifugal solvent extraction contactor was conceived and developed at Marcoule. This single stage contactor is composed of an outer stationary cylinder (made of transparent plexiglas on prototype and of stainless steel on models for hot cells) and a suspended inner rotating cylinder of stainless steel; the inside diameter of the rotor is 12 mm. Aqueous and organic phases are fed into the gap between the two cylinders. The mixture flows down the annular space and then up through an orifice at the bottom of the rotor. Into the rotor, the emulsion breaks rapidly under the centrifugal force (up to 600 g with rotor speed of 10,000 rpm). The separated phases flow over their weirs and discharge at the top in their collector rings. The liquid hold-up of this centrifugal contactor is approximately 6 mL. The use in hots cells needed original designs for: - the assembly of a single-stage contactor: every part (motor, rotor, stationary housing) is simply inserted on the other one without screws and nuts; - the assembly of multistage group: every stage is stacking in two rails and an intermediate part (supported on the two rails) links exit ports and their corresponding inlet ports. All the parts are pressed and sealed against a terminal plate with a screw. Separating capacity tests with. a prototype were conducted using water as the aqueous phase and hydrogenated tetra-propylene (TPH) as the organic phase with aqueous to organic (A/O) flow ratio equal to 1. The best performances were obtained with rotor speed ranging from 4000 to 5000 rpm; the total throughput was then up to 2 L.h -1 . For a total throughput of 300 mL.h -1 , the hold-up in the annular mixing zone varied from 0.5 to 1.5 mL according to the A/O ratio and the starting mode. A number of tests were also performed to measure the

Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica exchange method.

Science.gov (United States)

Lu, Qing; Kim, Jaegil; Straub, John E

2013-03-14

The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by "backbending" in the statistical temperature. While the metastable and unstable states in the vicinity of the first-order phase transition are masked by the enthalpy gap in temperature replica exchange method simulations, they are transformed into stable states through the parameterized effective sampling weights in gREM simulations, and join vapor and liquid phases with a succession of unimodal enthalpy distributions. The enhanced sampling across metastable and unstable states is achieved without the need to identify a "good" order parameter for biased sampling. We performed gREM simulations at various pressures below and near the critical pressure to examine the change in behavior of the vapor-liquid phase transition at different pressures. We observed a crossover from the first-order phase transition at low pressure, characterized by the backbending in the statistical temperature and the "kink" in the Gibbs free energy, to a continuous second-order phase transition near the critical pressure. The controlling mechanisms of nucleation and continuous phase transition are evident and the coexistence properties and phase diagram are found in agreement with literature results.

Open absorption system for cooling and air conditioning using membrane contactors. 2006 annual report

Energy Technology Data Exchange (ETDEWEB)

Conde-Petit, M. [M. Conde Engineering, Zuerich (Switzerland); Weber, R. [Materials Science and Technology (EMPA), Abteilung Bautechnologien, Duebendorf (Switzerland)

2006-11-15

This illustrated annual report for 2006 for the Swiss Federal Office of Energy (SFOE) reports on work being done on the development of an open absorption system for cooling and air-conditioning. The report reviews the construction of a first prototype and the manufacture of its components. The conceptual design of this new type of air handling unit (AHU), operating with a liquid desiccant, is discussed. The AHU is to be autonomous and the system will not require additional mechanical refrigeration. It is to be thermally driven at temperatures below 80 {sup o}C. Waste heat sources, solar collectors, district heating plants and co-generation systems are targeted as providers of thermal energy at this temperature level. Work carried out is reported on, including that on two-stream membrane contactors.

Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram

International Nuclear Information System (INIS)

Moretto, L.G.; Elliott, J.B.; Phair, L.

2003-01-01

In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A ∼ 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)

Surface science and model catalysis with ionic liquid-modified materials.

Science.gov (United States)

Steinrück, H-P; Libuda, J; Wasserscheid, P; Cremer, T; Kolbeck, C; Laurin, M; Maier, F; Sobota, M; Schulz, P S; Stark, M

2011-06-17

Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-vapor coexistence by molecular dynamics simulation

International Nuclear Information System (INIS)

Baranyai, Andras; Cummings, Peter T.

2000-01-01

We present a simple and consistent molecular dynamics algorithm for determining the equilibrium properties of a bulk liquid and its coexisting vapor phase. The simulation follows the dynamics of the two systems simultaneously while maintaining the volume and the number of particles of the composite system fixed. The thermostat can constrain either the total energy or the temperature at a desired value. Division of the extensive properties between the two phases is governed by the difference of the corresponding intensive state variables. Particle numbers are continuous variables and vary only in virtual sense, i.e., the real sizes of the two systems are the same and do not change during the course of the simulation. Calculation of the chemical potential is separate from the dynamics; thus, one can replace the particle exchange step with other method if it improves the efficiency of the code. (c) 2000 American Institute of Physics

Site-specific and multielement approach to the determination of liquid-vapor isotope fractionation parameters. The case of alcohols

International Nuclear Information System (INIS)

Moussa, I.; Naulet, N.; Martin, M.L.; Martin, G.J.

1990-01-01

Isotope fractionation phenomena occurring at the natural abundance level in the course of liquid-vapor transformation have been investigated by using the SNIF-NMR method (site-specific natural isotope fractionation studied by NMR) which has a unique capability of providing simultaneous access to fractionation parameters associated with different molecular isotopomers. This new approach has been combined with the determination of overall carbon and hydrogen fractionation effects by isotope ratio mass spectrometry (IRMS). The results of distillation and evaporation experiments of alcohols performed in technical conditions of practical interest have been analyzed according to the Rayleigh-type model. In order to check the performance of the column, unit fractionation factors were measured beforehand for water and for the hydroxylic sites of methanol and ethanol for which liquid-vapor equilibrium constants were already known. Inverse isotope effects are determined in distillation experiments for the overall carbon isotope ratio and for the site-specific hydrogen isotope ratios associated with the methyl and methylene sites of methanol and ethanol. In contrast, normal isotope effects are produced by distillation for the hydroxylic sites and by evaporation for all the isotopic ratios

Viscosity and Liquid Density of Asymmetric n-Alkane Mixtures: Measurement and Modelling

DEFF Research Database (Denmark)

Queimada, António J.; Marrucho, Isabel M.; Coutinho, João A.P.

2005-01-01

Viscosity and liquid density Measurements were performed, at atmospheric pressure. in pure and mixed n-decane. n-eicosane, n-docosane, and n-tetracosane from 293.15 K (or above the melting point) up to 343.15 K. The viscosity was determined with a rolling ball viscometer and liquid densities...... with a vibrating U-tube densimeter. Pure component results agreed, oil average, with literature values within 0.2% for liquid density and 3% for viscosity. The measured data were used to evaluate the performance of two models for their predictions: the friction theory coupled with the Peng-Robinson equation...... of state and a corresponding states model recently proposed for surface tension, viscosity, vapor pressure, and liquid densities of the series of n-alkanes. Advantages and shortcoming of these models are discussed....

Isothermogravimetric determination of the enthalpies of vaporization of 1-alkyl-3-methylimidazolium ionic liquids.

Science.gov (United States)

Luo, Huimin; Baker, Gary A; Dai, Sheng

2008-08-21

Vaporization enthalpies for two series of ionic liquids (ILs) composed of 1- n-alkyl-3-methylimidazolium cations, [Imm1+] (m=2, 3, 4, 6, 8, or 10), paired with either the bis(trifluoromethanesulfonyl)amide, [Tf2N-], or the bis(perfluoroethylsulfonyl)amide anion, [beti-], were determined using a simple, convenient, and highly reproducible thermogravimetric approach, and from these values, Hildebrand solubility parameters were estimated. Our results reveal two interesting and unanticipated outcomes: (i) methylation at the C2 position of [Imm1+] affords a significantly higher vaporization enthalpy; (ii) in all cases, the [beti-] anion served to lower the enthalpy of vaporization relative to [Tf2N-]. The widespread availability of the apparatus required for these measurements coupled with the ease of automation suggests the broad potential of this methodology for determining this critical parameter in a multitude of ILs.

Inhomogeneous Monte Carlo simulation of the vapor-liquid equilibrium of benzene between 300 K and 530 K

Directory of Open Access Journals (Sweden)

J.Janeček

2007-09-01

Full Text Available The inhomogeneous Monte Carlo technique is used in studying the vapor-liquid interface of benzene in a broad range of temperatures using the TraPPE potential field. The obtained values of the VLE parameters are in good agreement with the experimental values as well as with the results from GEMC simulations. In contrast to the GEMC, within one simulation box the inhomogeneous MC technique also yields information on the structural properties of the interphase between the two phases. The values of the vaporization enthalpy and the vapor pressure very well satisfy the Clausius-Clapeyron equation.

On the spatial stability of a liquid jet in the presence of vapor cavities

Energy Technology Data Exchange (ETDEWEB)

Lü, Ming; Ning, Zhi, E-mail: zhining@bjtu.edu.cn; Lu, Mei; Yan, Kai; Fu, Juan; Sun, Chunhua [College of Mechanical and Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

2013-11-15

A dispersion equation describing the effect of temperature differences on the stability of three-dimensional cylindrical liquid jets in the presence of vapor cavities is presented by the use of linear stability analysis. The mathematical model and its solving method are verified by comparing them with the data in the literature, and then the effect of temperature differences between jet and surrounding gas on the spatial stability of liquid jet is investigated. Some conclusions can be drawn from the results of this investigation: (1) the temperature difference destabilizes the liquid jet when the jet liquid is cooler than the surrounding gas, (2) the smallest atomized droplet without taking into account the effect of temperature differences is significantly larger than that when the effect of temperature differences is taken into account, (3) the effect of temperature differences on the stability of liquid jet has little relationship with azimuthal wave modes, (4) cavitation destabilizes the liquid jet when the value of the bubble volume fraction is not greater than 0.1 (0 ≤ α ≤ 0.1), and the temperature difference can weaken this effect of cavitation on the stability of liquid jet, and (5) cavitation is responsible for generating smaller droplets, the effect of cavitation on the critical wave number with and without taking into account the effect of temperature differences is quite different, and temperature difference is likely to fully restrain the effect of cavitation on the critical wave number; however, cavitation is again responsible for generating smaller droplets despite the effect of temperature differences when the bubble volume fraction α = 0.1. These findings may explain some observations of practical atomizer performance.

1996 scientific report; Rapport scientifique 1996

Energy Technology Data Exchange (ETDEWEB)

Berhouet, F.; Delavault, E.; Dupuy, P.; Legre, J.; Comte, M.; Panek, H.; Martin-Daguet, V.; Fleche, J.L.; Meis, C.; Kupecek, Ph.; Mennerat, G.; Mauchien, P.; Chaleard, C.; Kocon, S.; Lacour, J.L.; Gueneau, C.; Dauvois, V.; Gonella, C.; Berhier, C.; Lameille, J.M. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`enrichissement] [and others

1997-12-31

This report presents the work realized in 1996 by CEA-DCC (Direction du Cycle du Combustible). The main study fields are: laser beam stabilization, copper vapor laser (LVC) modelling, vapor density measurements, light transport in thick vapor, uranium evaporation, GdR-PRACTIS activities, uranyl organo phosphates, actinide extraction, ultra son in chemistry, oxidation mechanisms, salt free processes, tributyl phosphate (TBP) stability, cation exchanging membranes, filtering mineral membranes, liquid-liquid extraction processes, centrifugal contactor, supercritical phase, iodine reduction, weapon plutonium reprocessing, long term waste packaging, clay behaviour modelling; gas formation in deep storages, water-clay chemical interaction, nuclear glass behaviour, actinide storage dies, radionuclide release in storage, waste storage dies, iodine conditioning, cesium extraction by calix[4]arene molecules, decontamination foam, oxidation by supercritical water, decontamination by electrolysis, microorganism actions on metals, long life radionuclide determination in wastes, active and passive tomography, sulfated wastes, zircon-titanates ceramics, direct storage of irradiated fuel, caramel type fuel dismantling, radioprotection calculation codes, diffraction of backscattered electrons, infrared light coherent source, optical spectrometry, physical and chemical aspect of corium, iron-nickel-chromium alloy corrosion, natural uranium perspective, Atalante installation, interlaboratory comparisons. (A.C.)

1996 scientific report

International Nuclear Information System (INIS)

Berhouet, F.; Delavault, E.; Dupuy, P.; Legre, J.; Comte, M.; Panek, H.; Martin-Daguet, V.; Fleche, J.L.; Meis, C.; Kupecek, Ph.; Mennerat, G.; Mauchien, P.; Chaleard, C.; Kocon, S.; Lacour, J.L.; Gueneau, C.; Dauvois, V.; Gonella, C.; Berhier, C.; Lameille, J.M.

1997-01-01

This report presents the work realized in 1996 by CEA-DCC (Direction du Cycle du Combustible). The main study fields are: laser beam stabilization, copper vapor laser (LVC) modelling, vapor density measurements, light transport in thick vapor, uranium evaporation, GdR-PRACTIS activities, uranyl organo phosphates, actinide extraction, ultra son in chemistry, oxidation mechanisms, salt free processes, tributyl phosphate (TBP) stability, cation exchanging membranes, filtering mineral membranes, liquid-liquid extraction processes, centrifugal contactor, supercritical phase, iodine reduction, weapon plutonium reprocessing, long term waste packaging, clay behaviour modelling; gas formation in deep storages, water-clay chemical interaction, nuclear glass behaviour, actinide storage dies, radionuclide release in storage, waste storage dies, iodine conditioning, cesium extraction by calix[4]arene molecules, decontamination foam, oxidation by supercritical water, decontamination by electrolysis, microorganism actions on metals, long life radionuclide determination in wastes, active and passive tomography, sulfated wastes, zircon-titanates ceramics, direct storage of irradiated fuel, caramel type fuel dismantling, radioprotection calculation codes, diffraction of backscattered electrons, infrared light coherent source, optical spectrometry, physical and chemical aspect of corium, iron-nickel-chromium alloy corrosion, natural uranium perspective, Atalante installation, interlaboratory comparisons. (A.C.)

1996 scientific report; Rapport scientifique 1996

Energy Technology Data Exchange (ETDEWEB)

Berhouet, F; Delavault, E; Dupuy, P; Legre, J; Comte, M; Panek, H; Martin-Daguet, V; Fleche, J L; Meis, C; Kupecek, Ph; Mennerat, G; Mauchien, P; Chaleard, C; Kocon, S; Lacour, J L; Gueneau, C; Dauvois, V; Gonella, C; Berhier, C; Lameille, J M [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d` enrichissement; and others

1998-12-31

This report presents the work realized in 1996 by CEA-DCC (Direction du Cycle du Combustible). The main study fields are: laser beam stabilization, copper vapor laser (LVC) modelling, vapor density measurements, light transport in thick vapor, uranium evaporation, GdR-PRACTIS activities, uranyl organo phosphates, actinide extraction, ultra son in chemistry, oxidation mechanisms, salt free processes, tributyl phosphate (TBP) stability, cation exchanging membranes, filtering mineral membranes, liquid-liquid extraction processes, centrifugal contactor, supercritical phase, iodine reduction, weapon plutonium reprocessing, long term waste packaging, clay behaviour modelling; gas formation in deep storages, water-clay chemical interaction, nuclear glass behaviour, actinide storage dies, radionuclide release in storage, waste storage dies, iodine conditioning, cesium extraction by calix[4]arene molecules, decontamination foam, oxidation by supercritical water, decontamination by electrolysis, microorganism actions on metals, long life radionuclide determination in wastes, active and passive tomography, sulfated wastes, zircon-titanates ceramics, direct storage of irradiated fuel, caramel type fuel dismantling, radioprotection calculation codes, diffraction of backscattered electrons, infrared light coherent source, optical spectrometry, physical and chemical aspect of corium, iron-nickel-chromium alloy corrosion, natural uranium perspective, Atalante installation, interlaboratory comparisons. (A.C.)

Harvesting liquid from unsaturated vapor - nanoflows induced by capillary condensation

Science.gov (United States)

Vincent, Olivier; Marguet, Bastien; Stroock, Abraham

2016-11-01

A vapor, even subsaturated, can spontaneously form liquid in nanoscale spaces. This process, known as capillary condensation, plays a fundamental role in various contexts, such as the formation of clouds or the dynamics of hydrocarbons in the geological subsurface. However, large uncertainties remain on the thermodynamics and fluid mechanics of the phenomenon, due to experimental challenges as well as outstanding questions about the validity of macroscale physics at the nanometer scale. We studied experimentally the spatio-temporal dynamics of water condensation in a model nanoporous medium (pore radius 2 nm), taking advantage of the color change of the material upon hydration. We found that at low relative humidities ( 60 % RH, driven by a balance between the pore capillary pressure and the condensation stress given by Kelvin equation. Further analyzing the imbibition dynamics as a function of saturation allowed us to extract detailed information about the physics of nano-confined fluids. Our results suggest excellent extension of macroscale fluid dynamics and thermodynamics even in pores 10 molecules in diameter.

Effectiveness of Forestry Agency Personnel as Fire Prevention Contactors

Science.gov (United States)

M.L. Doolittle

1980-01-01

A major responsibility of county forest rangers in North Carolina is fire prevention. Personal contact with the public is essential to the successful performance of this function. A survey of 50 North Carolina rangers revealed that the degree of success for each ranger was directly related to the specific effort put forth as a contactor.

Prediction of the enthalpies of vaporization for room-temperature ionic liquids: Correlations and a substitution-based additive scheme

International Nuclear Information System (INIS)

Kabo, Gennady J.; Paulechka, Yauheni U.; Zaitsau, Dzmitry H.; Firaha, Alena S.

2015-01-01

Highlights: • The available literature data on Δ l g H for ionic liquids were analyzed. • Correlation equations for Δ l g H were derived using symbolic regression. • A substitution-based incremental scheme for Δ l g H was developed. • The proposed scheme has an advantage over the existing predictive procedures. - Abstract: The literature data on the enthalpies of vaporization for aprotic ionic liquids (ILs) published by the end of May 2014 were analyzed and the most reliable Δ l g H m values were derived for 68 ILs. The selected enthalpies of vaporization were correlated with density and surface tension using symbolic regression and a number of effective correlation equations were proposed. The substitution-based incremental scheme for prediction of the enthalpies of vaporization of imidazolium, pyridinium and pyrrolidinium ILs was developed. The standard error of the regression for the developed scheme is significantly lower than that for the atom-based group-contribution schemes proposed earlier

Force Field Benchmark of the TraPPE_UA for Polar Liquids: Density, Heat of Vaporization, Dielectric Constant, Surface Tension, Volumetric Expansion Coefficient, and Isothermal Compressibility.

Science.gov (United States)

Núñez-Rojas, Edgar; Aguilar-Pineda, Jorge Alberto; Pérez de la Luz, Alexander; de Jesús González, Edith Nadir; Alejandre, José

2018-02-08

The transferable potential for a phase equilibria force field in its united-atom version, TraPPE_UA, is evaluated for 41 polar liquids that include alcohols, thiols, ethers, sulfides, aldehydes, ketones, and esters to determine its ability to reproduce experimental properties that were not included in the parametrization procedure. The intermolecular force field parameters for pure components were fit to reproduce experimental boiling temperature, vapor-liquid coexisting densities, and critical point (temperature, density, and pressure) using Monte Carlo simulations in different ensembles. The properties calculated in this work are liquid density, heat of vaporization, dielectric constant, surface tension, volumetric expansion coefficient, and isothermal compressibility. Molecular dynamics simulations were performed in the gas and liquid phases, and also at the liquid-vapor interface. We found that relative error between calculated and experimental data is 1.2% for density, 6% for heat of vaporization, and 6.2% for surface tension, in good agreement with the experimental data. The dielectric constant is systematically underestimated, and the relative error is 37%. Evaluating the performance of the force field to reproduce the volumetric expansion coefficient and isothermal compressibility requires more experimental data.

Hollow Fiber Membrane Contactors for Post-Combustion CO2 Capture: A Scale-Up Study from Laboratory to Pilot Plant

Directory of Open Access Journals (Sweden)

Chabanon E.

2014-11-01

Full Text Available Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfortunately almost systematically on small, laboratory scale, modules. Given the level of flue gas flow rates which have to be treated for carbon capture applications, a consistent scale-up methodology is obviously needed for a rigorous engineering design. In this study, the possibilities and limitations of scale-up strategies for membrane contactors have been explored and will be discussed. Experiments (CO2 absorption from a gas mixture in a 30%wt MEA aqueous solution have been performed both on mini-modules and at pilot scale (10 m2 membrane contactor module based on PTFE hollow fibers. The results have been modelled utilizing a resistance in series approach. The only adjustable parameter is in fitting the simulations to experimental data is the membrane mass transfer coefficient (km, which logically plays a key role. The difficulties and uncertainties associated with scaleup computations from lab scale to pilot scale modules, with a particular emphasis on the km value, are presented and critically discussed.

X-ray diffuse scattering study of height fluctuations at the liquid-vapor interface of gallium

Energy Technology Data Exchange (ETDEWEB)

Lin Binhua [CARS, University of Chicago, Chicago, IL 60637 (United States); Meron, Mati [CARS, University of Chicago, Chicago, IL 60637 (United States); Gebhardt, Jeff [CARS, University of Chicago, Chicago, IL 60637 (United States); Graber, Tim [CARS, University of Chicago, Chicago, IL 60637 (United States); Li Dongxu [Department of Chemistry and James Franck Institute, University of Chicago, Chicago, IL 60637 (United States); Yang Bin [Department of Chemistry and James Franck Institute, University of Chicago, Chicago, IL 60637 (United States); Rice, Stuart A. [Department of Chemistry and James Franck Institute, University of Chicago, Chicago, IL 60637 (United States)]. E-mail: s-rice@uchicago.edu

2005-02-28

We report an experimental study of wavelength dependent interfacial tension of liquid Ga using X-ray surface diffusion scattering. The observed surface tension can be explained by Mecke-Dietrich formalism derived from a microscopic density functional theory when the known stratified liquid-vapor interfacial density profile of Ga and a so-called individual local pseudo-potential for the pair-interaction potential of liquid metal are used. The quantitative behavior of the surface tension as a function of wavelength is very sensitive to the forms of both the interfacial density profile and the asymptotic part of the pair-potential, and is different from that observed from several dielectric liquids reported previously (Nature 403 (2000) 871; Phys. Rev. Lett. 90 (2003) 216101)

Extended vapor-liquid-solid growth of silicon carbide nanowires.

Science.gov (United States)

Rajesh, John Anthuvan; Pandurangan, Arumugam

2014-04-01

We developed an alloy catalytic method to explain extended vapor-liquid-solid (VLS) growth of silicon carbide nanowires (SiC NWs) by a simple thermal evaporation of silicon and activated carbon mixture using lanthanum nickel (LaNi5) alloy as catalyst in a chemical vapor deposition process. The LaNi5 alloy binary phase diagram and the phase relationships in the La-Ni-Si ternary system were play a key role to determine the growth parameters in this VLS mechanism. Different reaction temperatures (1300, 1350 and 1400 degrees C) were applied to prove the established growth process by experimentally. Scanning electron microscopy and transmission electron microscopy studies show that the crystalline quality of the SiC NWs increases with the temperature at which they have been synthesized. La-Ni alloyed catalyst particles observed on the top of the SiC NWs confirms that the growth process follows this extended VLS mechanism. The X-ray diffraction and confocal Raman spectroscopy analyses demonstrate that the crystalline structure of the SiC NWs was zinc blende 3C-SiC. Optical property of the SiC NWs was investigated by photoluminescence technique at room temperature. Such a new alloy catalytic method may be extended to synthesis other one-dimensional nanostructures.

Temperature Profile Measurements in a Newly Constructed 30-Stage 5 cm Centrifugal Contactor Pilot Plant

International Nuclear Information System (INIS)

Garn, Troy G.; Meikrantz, Dave H.; Greenhalgh, Mitchell R.; Law, Jack D.

2008-01-01

An annular centrifugal contactor pilot plant incorporating 30 stages of commercial 5 cm CINC V-02 units has been built and operated at INL during the past year. The pilot plant includes an automated process control and data acquisitioning system. The primary purpose of the pilot plant is to evaluate the performance of a large number of inter-connected centrifugal contactors and obtain temperature profile measurements within a 30-stage cascade. Additional solvent extraction flowsheet testing using stable surrogates is also being considered. Preliminary hydraulic testing was conducted with all 30 contactors interconnected for continuous counter-current flow. Hydraulic performance and system operational tests were conducted successfully but with higher single-stage rotor speeds found necessary to maintain steady interstage flow at flowrates of 1 L/min and higher. Initial temperature profile measurements were also completed in this configuration studying the performance during single aqueous and two-phase counter-current flow at ambient and elevated inlet solution temperatures. Temperature profile testing of two discreet sections of the cascade required additional feed and discharge connections. Lamp oil, a commercially available alkane mixture of C14 to C18 chains, and tap water adjusted to pH 2 were the solution feeds for all the testing described in this report. Numerous temperature profiles were completed using a newly constructed 30-stage centrifugal contactor pilot plant. The automated process control and data acquisition system worked very well throughout testing. Temperature data profiles for an array of total flowrates (FT) and contactor rpm values for both single-phase and two-phase systems have been collected with selected profiles and comparisons reported. Total flowrates (FT) ranged from 0.5-1.4 L/min with rotor speeds from 3500-4000 rpm. Solution inlet temperatures ranging from ambient up to 50 C were tested. Ambient temperature testing shows that a small

Modeling of venturi scrubber efficiency

Science.gov (United States)

Crowder, Jerry W.; Noll, Kenneth E.; Davis, Wayne T.

The parameters affecting venturi scrubber performance have been rationally examined and modifications to the current modeling theory have been developed. The modified model has been validated with available experimental data for a range of throat gas velocities, liquid-to-gas ratios and particle diameters and is used to study the effect of some design parameters on collection efficiency. Most striking among the observations is the prediction of a new design parameter termed the minimum contactor length. Also noted is the prediction of little effect on collection efficiency with increasing liquid-to-gas ratio above about 2ℓ m-3. Indeed, for some cases a decrease in collection efficiency is predicted for liquid rates above this value.

Theoretical analysis of the axial growth of nanowires starting with a binary eutectic droplet via vapor-liquid-solid mechanism

Science.gov (United States)

Liu, Qing; Li, Hejun; Zhang, Yulei; Zhao, Zhigang

2018-06-01

A series of theoretical analysis is carried out for the axial vapor-liquid-solid (VLS) growth of nanowires starting with a binary eutectic droplet. The growth model considering the entire process of axial VLS growth is a development of the approaches already developed by previous studies. In this model, the steady and unsteady state growth are considered both. The amount of solute species in a variable liquid droplet, the nanowire length, radius, growth rate and all other parameters during the entire axial growth process are treated as functions of growth time. The model provides theoretical predictions for the formation of nanowire shape, the length-radius and growth rate-radius dependences. It is also suggested by the model that the initial growth of single nanowire is significantly affected by Gibbs-Thompson effect due to the shape change. The model was applied on predictions of available experimental data of Si and Ge nanowires grown from Au-Si and Au-Ge systems respectively reported by other works. The calculations with the proposed model are in satisfactory agreement with the experimental results of the previous works.

Thermal behaviour of agitated gas-liquid reactors with a vaporizing solvent/air oxidation of hydrocarbons

NARCIS (Netherlands)

Westerterp, K.R.; Crombeen, P.R.J.J.

1983-01-01

Many highly exothermic gas-liquid reactions are carried out with a vaporizing solvent, which after condensation is returned to the reactor. In this way the liberated reaction heat for a large part is absorbed by the cooling water flowing through the condenser. In order to determine the influence of

The study of water + HCl + ethanol vapor-liquid equilibrium at 78 kPa

International Nuclear Information System (INIS)

Ojeda Toro, Juan Carlos; Dobrosz-Gómez, Izabela; Gómez García, Miguel Ángel

2017-01-01

Graphical abstract: Comparison between experimental and calculated saturation temperature of water + HCl + ethanol system using two rigorous electrolyte models. - Highlights: • Data for the water + HCl + ethanol VLE is reported at 78 kPa. • The VLE for the system water + HCl + ethanol was determined. • A new set of parameters for extended UNIQUAC model were correlated. • A new set of parameters for LIQUAC model were correlated. - Abstract: In this work, the isobaric vapor-liquid equilibrium (VLE) data obtained for the ternary system water + HCl + ethanol at 78 kPa, using an Ellis still, were studied. Two rigorous electrolyte models (extended UNIQUAC and LIQUAC) were fitted to the experimental data. Ethanol-H + , water-H + , ethanol-Cl − , water-Cl − , and Cl − -H + interaction parameters were determined. Likewise, Henry’s law constants for the volatile electrolyte were defined. A high goodness of fit was obtained for both electrolyte models; however, the extended UNIQUAC one showed better performance (AAD = 0.1326%). Two azeotropes observed in the system were accurately predicted (ethanol + water: x EtOH = 0.86 at 344.6 K; and HCl + water: x HCl = 0.11 at 375.5 K).

Partitioning of Tank Waste Sludge in a 5-cm Centrifugal Contactor Under Caustic-Side Solvent Extraction Conditions

International Nuclear Information System (INIS)

Birdwell, Jr. J.F.

2001-01-01

A test program has been performed to evaluate the effect of solids on the hydraulic performance of a 5-cm centrifugal contactor under conditions present in the extraction section of the Caustic-Side Solvent Extraction (CSSX) process. In addition to determining if the ability to separate the aqueous and organic phases is affected by the presence of solids in a feed solution, the extent to which solids are accumulated in the contactor was also assessed. The reported task was motivated by the need to determine if removal of cesium from Savannah River Site tank waste can be performed using a contactor-based CSSX process without first removing sludge that is suspended in the feed solution. The ability to pass solids through the CSSX process could facilitate placement of CSSX upstream of a process in which alpha-decaying actinides and strontium are removed from the waste stream by precipitation with monosodium titanate (MST). This relative placement of the CSSX and MST processes is desirable because removal of cesium would greatly reduce the activity level of the feed stream to the MST process, thereby reducing the level of shielding needed and mitigating remote maintenance design features of MST equipment. Both results would significantly reduce the cost of the Salt Processing Project. Test results indicate conclusively that a large fraction of suspended sludge that enters the centrifugal contactor remains inside. It is expected that extended operation would result in continued accumulation of solids and that hydraulic performance would be adversely affected. Results also indicate that a fraction of the solids partitions to the phase boundary and could affect phase separation as contactor operations progress

In situ separation of root hydraulic redistribution of soil water from liquid and vapor transport

Energy Technology Data Exchange (ETDEWEB)

Warren, Jeffrey [ORNL; Brooks, J Renee [U.S. Environmental Protection Agency, Corvallis, OR; Dragila, Maria [Oregon State University, Corvallis; Meinzer, Rick [USDA Forest Service

2011-01-01

Nocturnal increases in water potential ( ) and water content (WC) in the upper soil profile are often attributed to root water efflux into the soil, a process termed hydraulic lift or hydraulic redistribution (HR). We have previously reported HR values up to ~0.29 mm day-1 in the upper soil for a seasonally dry old-growth ponderosa pine site. However, unsaturated liquid or vapor flux of water between soil layers independent of roots also contributes to the diurnal patterns in WC, confounding efforts to determine the actual magnitude of HR. In this study, we estimated liquid (Jl) and vapor (Jv) soil water fluxes and their impacts on quantifying HR in situ by applying existing data sets of , WC, temperature (T) and soil physical properties to soil water transport equations. Under moist conditions, Jl between layers was estimated to be larger than necessary to account for measured nocturnal increases in WC of upper soil layers. However, as soil drying progressed unsaturated hydraulic conductivity declined rapidly such that Jl was irrelevant (< 2E-06 cm hr-1 at 0-60 cm depths) to total water flux by early August. In surface soil at depths above 15 cm, large T fluctuations can impact Jv leading to uncertainty concerning the role, if any, of HR in nocturnal WC dynamics. Vapor flux was estimated to be the highest at the shallowest depths measured (20 - 30 cm) where it could contribute up to 40% of hourly increases in nocturnal soil moisture depending on thermal conditions. While both HR and net soil water flux between adjacent layers contribute to WC in the 15-65 cm soil layer, HR was the dominant process and accounted for at least 80% of the diurnal increases in WC. While the absolute magnitude of HR is not easily quantified, total diurnal fluctuations in upper soil water content can be quantified and modeled, and remain highly applicable for establishing the magnitude and temporal dynamics of total ecosystem water flux.

Perspective: Highly stable vapor-deposited glasses

Science.gov (United States)

Ediger, M. D.

2017-12-01

This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the "ideal glass." Connections between vapor-deposited glasses, liquid-cooled glasses, and deeply supercooled liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.

Effect of carbon derivatives in sulfonated poly(etherimide)-liquid crystal polymer composite for methanol vapor sensing

Science.gov (United States)

Bag, Souvik; Rathi, Keerti; Pal, Kaushik

2017-05-01

A class of highly sensitive chemiresistive sensors is developed for methanol (MeOH) vapor detection in ambient atmosphere by introducing conductive nanofillers like carbon black, multi-wall carbon nanotubes, and reduced graphene oxide into sulfonated poly(etherimide) (PEI)/liquid crystal polymer (LCP) composite (sPEI-LCP). Polar composites are prepared by a sulfonation process for instantaneous enhancement in adsorption capability of the sensing films to the target analyte (MeOH). Sensing properties exhibit that polymer composite-based fabricated sensors are efficient for the detection of different concentration of methanol vapor from 300-1200 parts-per-million (ppm) at room temperature. The incorporation of nanofiller induces the dramatic change in sensing behavior of base composite film (sPEI-LCP). Thus, less mass fraction of nanofillers (i.e. 2 wt%) influences the nonlinear sensing behavior for the entire range of methanol vapor. The simple method and low fabrication cost of the prepared sensor are compelling reasons that methanol vapor sensor is suitable for environmental monitoring.

Theoretical studies on membrane-based gas separation using computational fluid dynamics (CFD) of mass transfer

International Nuclear Information System (INIS)

Sohrabi, M.R.; Marjani, A.; Davallo, M.; Moradi, S.; Shirazian, S.

2011-01-01

A 2D mass transfer model was developed to study carbon dioxide removal by absorption in membrane contactors. The model predicts the steady state absorbent and carbon dioxide concentrations in the membrane by solving the conservation equations. The continuity equations for three sub domains of the membrane contactor involving the tube; membrane and shell were obtained and solved by finite element method (FEM). The model was based on 'non-wetted mode' in which the gas phase filled the membrane pores. Laminar parabolic velocity profile was used for the liquid flow in the tube side; whereas, the gas flow in the shell side was characterized by Happel's free surface model. Axial and radial diffusion transport inside the shell, through the membrane, and within the tube side of the contactor was considered in the mass transfer model. The predictions of percent CO/sub 2/ removal obtained by modeling were compared with the experimental values obtained from literature. They were the experimental results for CO/sub 2/ removal from CO/sub 2//N/sub 2/ gas mixture with amines aqueous solutions as the liquid solvent using polypropylene membrane contactor. The modeling predictions were in good agreement with the experimental values for different values of gas and liquid flow rates. (author)

Dynamic Leidenfrost temperature on micro-textured surfaces: Acoustic wave absorption into thin vapor layer

Science.gov (United States)

Jerng, Dong Wook; Kim, Dong Eok

2018-01-01

The dynamic Leidenfrost phenomenon is governed by three types of pressure potentials induced via vapor hydrodynamics, liquid dynamic pressure, and the water hammer effect resulting from the generation of acoustic waves at the liquid-vapor interface. The prediction of the Leidenfrost temperature for a dynamic droplet needs quantitative evaluation and definition for each of the pressure fields. In particular, the textures on a heated surface can significantly affect the vapor hydrodynamics and the water hammer pressure. We present a quantitative model for evaluating the water hammer pressure on micro-textured surfaces taking into account the absorption of acoustic waves into the thin vapor layer. The model demonstrates that the strength of the acoustic flow into the liquid droplet, which directly contributes to the water hammer pressure, depends on the magnitude of the acoustic resistance (impedance) in the droplet and the vapor region. In consequence, the micro-textures of the surface and the increased spacing between them reduce the water hammer coefficient ( kh ) defined as the ratio of the acoustic flow into the droplet to total generated flow. Aided by numerical calculations that solve the laminar Navier-Stokes equation for the vapor flow, we also predict the dynamic Leidenfrost temperature on a micro-textured surface with reliable accuracy consistent with the experimental data.

Evaluation of the Hydraulic Performance and Mass Transfer Efficiency of the CSSX Process with the Optimized Solvent in a Single Stage of 5.5-Cm Diameter Centrifugal Contactor

International Nuclear Information System (INIS)

Law, J.D.; Tillotson, R.D.; Todd, T.A.

2002-01-01

The Caustic-Side Solvent Extraction (CSSX) process has been selected for the separation of cesium from Savannah River Site high-level waste. The solvent composition used in the CSSX process was recently optimized so that the solvent is no longer supersaturated with respect to the calixarene crown ether extractant. Hydraulic performance and mass transfer efficiency testing of a single stage of 5.5-cm ORNL-designed centrifugal contactor has been performed for the CSSX process with the optimized solvent. Maximum throughputs of the 5.5-cm centrifugal contactor, as a function of contactor rotor speed, have been measured for the extraction, scrub, strip, and wash sections of the CSSX flowsheet at the baseline organic/aqueous flow ratios (O/A) of the process, as well as at O/A's 20% higher and 20% lower than the baseline. Maximum throughputs are comparable to the design throughput of the contactor, as well as with throughputs obtained previously in a 5-cm centrifugal contactor with the non-optimized CSSX solvent formulation. The 20% variation in O/A had minimal effect on contactor throughput. Additionally, mass transfer efficiencies have been determined for the extraction and strip sections of the flowsheet. Efficiencies were lower than the process goal of greater than or equal to 80%, ranging from 72 to 75% for the extraction section and from 36 to 60% in the strip section. Increasing the mixing intensity and/or the solution level in the mixing zone of the centrifugal contactor (residence time) could potentially increase efficiencies. Several methods are available to accomplish this including (1) increasing the size of the opening in the bottom of the rotor, resulting in a contactor which is partially pumping instead of fully pumping, (2) decreasing the number of vanes in the contactor, (3) increasing the vane height, or (4) adding vanes on the rotor and baffles on the housing of the contactor. The low efficiency results obtained stress the importance of proper design of

Single Stage Contactor Testing Of The Next Generation Solvent Blend

Energy Technology Data Exchange (ETDEWEB)

Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

2014-01-06

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

Revisiting a many-body model for water based on a single polarizable site: from gas phase clusters to liquid and air/liquid water systems.

Science.gov (United States)

Réal, Florent; Vallet, Valérie; Flament, Jean-Pierre; Masella, Michel

2013-09-21

We present a revised version of the water many-body model TCPE [M. Masella and J.-P. Flament, J. Chem. Phys. 107, 9105 (1997)], which is based on a static three charge sites and a single polarizable site to model the molecular electrostatic properties of water, and on an anisotropic short range many-body energy term specially designed to accurately model hydrogen bonding in water. The parameters of the revised model, denoted TCPE/2013, are here developed to reproduce the ab initio energetic and geometrical properties of small water clusters (up to hexamers) and the repulsive water interactions occurring in cation first hydration shells. The model parameters have also been refined to reproduce two liquid water properties at ambient conditions, the density and the vaporization enthalpy. Thanks to its computational efficiency, the new model range of applicability was validated by performing simulations of liquid water over a wide range of temperatures and pressures, as well as by investigating water liquid/vapor interfaces over a large range of temperatures. It is shown to reproduce several important water properties at an accurate enough level of precision, such as the existence liquid water density maxima up to a pressure of 1000 atm, the water boiling temperature, the properties of the water critical point (temperature, pressure, and density), and the existence of a "singularity" temperature at about 225 K in the supercooled regime. This model appears thus to be particularly well-suited for characterizing ion hydration properties under different temperature and pressure conditions, as well as in different phases and interfaces.

Measurements of isothermal (vapor + liquid) phase equilibrium for {trifluoroiodomethane (R13I1) + 1,1-difluoroethane (R152a)} from T = (258.150 to 283.150) K

International Nuclear Information System (INIS)

Gong, Maoqiong; Cheng, Kuiwei; Dong, Xueqiang; Guo, Hao; Zhao, Yanxing; Wu, Jianfeng

2015-01-01

Highlights: • VLE data for (R13I1 + R152a) system were measured at four temperatures. • Experiments were based on the vapor-recirculation method. • VLE data were correlated using PR−VdWs and PR−HV−NRTL models. • Azeotropic behavior can be found. - Abstract: In this paper, isothermal (vapor + liquid) equilibrium (VLE) values for {trifluoroiodomethane (R13I1) + 1,1-difluoroethane (R152a)} at T = (258.150 to 283.150) K are presented. The experimental apparatus was based on a vapor-recirculation method. The VLE measurements were regressed by the Peng–Robinson equation of state with two models, the Van der Waals mixing rules and the Huron–Vidal mixing rules using the NRTL activity coefficient model. The newly measured VLE values satisfied the thermodynamic consistency test. The results have led to that the two models selected are both suitable for the description of the binary system. Azeotropic behavior can be found for the system measured

Electrochemical Model for Ionic Liquid Electrolytes in Lithium Batteries

International Nuclear Information System (INIS)

Yoo, Kisoo; Deshpande, Anirudh; Banerjee, Soumik; Dutta, Prashanta

2015-01-01

ABSTRACT: Room temperature ionic liquids are considered as potential electrolytes for high performance and safe lithium batteries due to their very low vapor pressure and relatively wide electrochemical and thermal stability windows. Unlike organic electrolytes, ionic liquid electrolytes are molten salts at room temperature with dissociated cations and anions. These dissociated ions interfere with the transport of lithium ions in lithium battery. In this study, a mathematical model is developed for transport of ionic components to study the performance of ionic liquid based lithium batteries. The mathematical model is based on a univalent ternary electrolyte frequently encountered in ionic liquid electrolytes of lithium batteries. Owing to the very high concentration of components in ionic liquid, the transport of lithium ions is described by the mutual diffusion phenomena using Maxwell-Stefan diffusivities, which are obtained from atomistic simulation. The model is employed to study a lithium-ion battery where the electrolyte comprises ionic liquid with mppy + (N-methyl-N-propyl pyrrolidinium) cation and TFSI − (bis trifluoromethanesulfonyl imide) anion. For a moderate value of reaction rate constant, the electric performance results predicted by the model are in good agreement with experimental data. We also studied the effect of porosity and thickness of separator on the performance of lithium-ion battery using this model. Numerical results indicate that low rate of lithium ion transport causes lithium depleted zone in the porous cathode regions as the porosity decreases or the length of the separator increases. The lithium depleted region is responsible for lower specific capacity in lithium-ion cells. The model presented in this study can be used for design of optimal ionic liquid electrolytes for lithium-ion and lithium-air batteries

Transport evaluation of a gas-liquid scrubber

International Nuclear Information System (INIS)

Brodner, A.J.; Bistline, J.E.; Weber, S.E.

1982-10-01

The hydraulics and the mass-transfer behavior of a five-tray, single-bubble-cap, single-downcomer, gas-liquid contactor were studied for use as a gas scrubber. Flooding was not observed at the maximum available liquid and gas flow rates of 0.32 and 464 L/min, respectively. The maximum liquid entrainment was 33% at a gross liquid flow rate of 0.05 L/min. The Murphree-tray efficiencies for absorption of CO 2 (5000 ppM in air) into demineralized water ranged from 0.14 to 0.74 for volumetric liquid-to-gas ratios of 4 x 10 -4 and 2 x 10 -4 , respectively, for k/sub L/a values ranging from 0.088 to 0.36 min -1 . 12 figures, 10 tables

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric plutonium dioxide at high temperatures

International Nuclear Information System (INIS)

Green, D.W.; Fink, J.K.; Leibowitz, L.

1982-01-01

Vapor pressures and vapor compositions have been calculated for 1500 less than or equal to T less than or equal to 4000 0 K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model extended into the liquid region to obtain the partial pressures of O 2 , O, Pu, PuO and PuO 2 . The calculated oxygen pressures increase very rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu 6 + from the oxygen-potential model. No reliable method was found to estimate the importance of this ion. As a result of large oxygen potentials at high temperatures, extremely high total pressures that produced unreasonably high vapor densities were calculated. The highest temperature was therefore limited to 400 K, and the range of oxygen-to-metal ratios was limited to 1.994 to 1.70. These calculations show that vapor in equilibrium with hypostoichiometric plutonium dioxide is poorly approximated as PuO 2 for most of the temperture and composition range of interest. The vapor is much more oxygen-rich than the condensed phase. Implications for the (U,Pu)O/sub 2-x/ system are discussed

Condensation of vapor bubble in subcooled pool

Science.gov (United States)

Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

2017-02-01

We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

Study of the liquid vapor equilibrium in the bromine-hydrobromic acid-water system

Science.gov (United States)

Benizri, R.; Lessart, P.; Courvoisier, P.

1984-01-01

A glass ebullioscope was built and at atmospheric pressure, liquid-vapor equilibria relative to the Br2-HBr-H2O system, in the concentration range of interest for evaluation of the Mark 13 cycle was studied. Measurements were performed for the brome-azeotrope (HBr-H2O) pseudo-binary system and for the ternary system at temperatures lower than 125 C and in the bromine concentration range up to 13% wt.

In situ separation of root hydraulic redistribution of soil water from liquid and vapor transport

Science.gov (United States)

Jeffrey M. Warren; J. Renée Brooks; Maria I. Dragila; Frederick C. Meinzer

2011-01-01

Nocturnal increases in water potential and water content in the upper soil profile are often attributed to root water efflux, a process termed hydraulic redistribution (HR). However, unsaturated liquid or vapor flux of water between soil layers independent of roots also contributes to the daily recovery in water content, confounding efforts to determine the actual...

Carbon Dioxide Absorption in a Membrane Contactor with Color Change

Science.gov (United States)

Pantaleao, Ines; Portugal, Ana F.; Mendes, Adelio; Gabriel, Joaquim

2010-01-01

A pedagogical experiment is described to examine the physical absorption of gases, in this case carbon dioxide, in a hollow fiber membrane contactor (HFMC) where the absorption concentration profile can be followed by a color change. The HFMC is used to teach important concepts and can be used in interesting applications for students, such as…

Mathematical modelling of liquid meniscus shape in cylindrical micro-channel for normal and micro gravity conditions

Science.gov (United States)

Marchuk, Igor; Lyulin, Yuriy

2017-10-01

Mathematical model of liquid meniscus shape in cylindrical micro-channel of the separator unit of condensing/separating system is presented. Moving liquid meniscus in the 10 μm cylindrical microchannel is used as a liquid lock to recover the liquid obtained by condensation from the separators. The main goal of the liquid locks to prevent penetration of a gas phase in the liquid line at the small flow rate of the condensate and because of pressure fluctuations in the vapor-gas-liquid loop. Calculation of the meniscus shape has been performed for liquid FC-72 at different values of pressure difference gas - liquid and under normal and micro gravity conditions.

Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field

Science.gov (United States)

Boziuk, Thomas; Smith, Marc; Glezer, Ari

2016-11-01

Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

Charge transfer effects of ions at the liquid water/vapor interface

Energy Technology Data Exchange (ETDEWEB)

Soniat, Marielle; Rick, Steven W., E-mail: srick@uno.edu [Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148 (United States)

2014-05-14

Charge transfer (CT), the movement of small amounts of electron density between non-bonded pairs, has been suggested as a driving force for a variety of physical processes. Herein, we examine the effect of CT on ion adsorption to the water liquid-vapor interface. Using a CT force field for molecular dynamics, we construct a potential of mean force (PMF) for Na{sup +}, K{sup +}, Cl{sup −}, and I{sup −}. The PMFs were produced with respect to an average interface and an instantaneous interface. An analysis of the PMF relative to the instantaneous surface reveals that the area in which the anions experience a free energy minimum is quite narrow, and the cations feel a steeply repulsive free energy near the interface. CT is seen to have only minor effects on the overall free energy profiles. However, the long-ranged effects of ions are highlighted by the CT model. Due to CT, the water molecules at the surface become charged, even when the ion is over 15 Å away from the surface.

Surface boiling of superheated liquid

Energy Technology Data Exchange (ETDEWEB)

Reinke, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-01-01

A basic vaporization mechanism that possibly affects the qualitative and quantitative prediction of the consequences of accidental releases of hazardous superheated liquids was experimentally and analytically investigated. The studies are of relevance for the instantaneous failure of a containment vessel filled with liquefied gas. Even though catastrophical vessel failure is a rare event, it is considered to be a major technological hazard. Modeling the initial phase of depressurisation and vaporization of the contents is an essential step for the subsequent analysis of the spread and dispersion of the materials liberated. There is only limited understanding of this inertial expansion stage of the superheated liquid, before gravity and atmospheric turbulence begin to dominate the expansion. This work aims at a better understanding of the vaporization process and to supply more precise source-term data. It is also intended to provide knowledge for the prediction of the behavior of large-scale releases by the investigation of boiling on a small scale. Release experiments with butane, propane, R-134a and water were conducted. The vaporization of liquids that became superheated by sudden depressurisation was studied in nucleation-site-free glass receptacles. Several novel techniques for preventing undesired nucleation and for opening the test-section were developed. Releases from pipes and from a cylindrical geometry allowed both linear one-dimensional, and radial-front two-dimensional propagation to be investigated. Releases were made to atmospheric pressure over a range of superheats. It was found that, above a certain superheat temperature, the free surface of the metastable liquid rapidly broke up and ejected a high-velocity vapor/liquid stream. The zone of intense vaporization and liquid fragmentation proceeded as a front that advanced into the test fluids. No nucleation of bubbles in the bulk of the superheated liquid was observed. (author) figs., tabs., refs.

Surface boiling of superheated liquid

International Nuclear Information System (INIS)

Reinke, P.

1997-01-01

A basic vaporization mechanism that possibly affects the qualitative and quantitative prediction of the consequences of accidental releases of hazardous superheated liquids was experimentally and analytically investigated. The studies are of relevance for the instantaneous failure of a containment vessel filled with liquefied gas. Even though catastrophical vessel failure is a rare event, it is considered to be a major technological hazard. Modeling the initial phase of depressurisation and vaporization of the contents is an essential step for the subsequent analysis of the spread and dispersion of the materials liberated. There is only limited understanding of this inertial expansion stage of the superheated liquid, before gravity and atmospheric turbulence begin to dominate the expansion. This work aims at a better understanding of the vaporization process and to supply more precise source-term data. It is also intended to provide knowledge for the prediction of the behavior of large-scale releases by the investigation of boiling on a small scale. Release experiments with butane, propane, R-134a and water were conducted. The vaporization of liquids that became superheated by sudden depressurisation was studied in nucleation-site-free glass receptacles. Several novel techniques for preventing undesired nucleation and for opening the test-section were developed. Releases from pipes and from a cylindrical geometry allowed both linear one-dimensional, and radial-front two-dimensional propagation to be investigated. Releases were made to atmospheric pressure over a range of superheats. It was found that, above a certain superheat temperature, the free surface of the metastable liquid rapidly broke up and ejected a high-velocity vapor/liquid stream. The zone of intense vaporization and liquid fragmentation proceeded as a front that advanced into the test fluids. No nucleation of bubbles in the bulk of the superheated liquid was observed. (author) figs., tabs., refs

Membrane contactor/separator for an advanced ozone membrane reactor for treatment of recalcitrant organic pollutants in water

International Nuclear Information System (INIS)

Chan, Wai Kit; Jouët, Justine; Heng, Samuel; Yeung, King Lun; Schrotter, Jean-Christophe

2012-01-01

An advanced ozone membrane reactor that synergistically combines membrane distributor for ozone gas, membrane contactor for pollutant adsorption and reaction, and membrane separator for clean water production is described. The membrane reactor represents an order of magnitude improvement over traditional semibatch reactor design and is capable of complete conversion of recalcitrant endocrine disrupting compounds (EDCs) in water at less than three minutes residence time. Coating the membrane contactor with alumina and hydrotalcite (Mg/Al=3) adsorbs and traps the organics in the reaction zone resulting in 30% increase of total organic carbon (TOC) removal. Large surface area coating that diffuses surface charges from adsorbed polar organic molecules is preferred as it reduces membrane polarization that is detrimental to separation. - Graphical abstract: Advanced ozone membrane reactor synergistically combines membrane distributor for ozone, membrane contactor for sorption and reaction and membrane separator for clean water production to achieve an order of magnitude enhancement in treatment performance compared to traditional ozone reactor. Highlights: ► Novel reactor using membranes for ozone distributor, reaction contactor and water separator. ► Designed to achieve an order of magnitude enhancement over traditional reactor. ► Al 2 O 3 and hydrotalcite coatings capture and trap pollutants giving additional 30% TOC removal. ► High surface area coating prevents polarization and improves membrane separation and life.

Effects of solvent-extraction contactor selection on flowsheet and facility design

International Nuclear Information System (INIS)

Whatley, M.E.

1982-01-01

The notion is developed that the selection of a solvent extraction contactor is part of a more general development of principles and philosophy guiding the overall plant design. Specifically, the requirements and constraints placed on the plant by the solvent extraction system must be consistent with those imposed by the other operations, which generally are more expensive and more complicated. Were a conservative philosophy employed throughout the plant, the choice of pulsed columns seem correct. Were the plant intended to employ modern techniques and state-of-the-art technology, particularly in remote maintenance and process control, the selection of centrifugal contactors seems appropriate. The process improvements attainable from employing more stages in a more tightly controlled solvent extraction system seem marginal at present when applied to conventional flowsheets, although the cost-benefit may be attractive in a modern plant. The potential for improvement through major flowsheet modification can not presently be assessed quantitatively

Study on the performance of the hydraulic and mass-transfer with miniature centrifugal contactor

International Nuclear Information System (INIS)

Wang Jianchen; Tang Wencheng; Fan Shilei; Lian Jun

1997-01-01

The hydraulic performance and the mass-transfer properties of HNO 3 , Fe 3+ , Nd 3+ are studied in H 2 O-30% TRPO-kerosene system at different conditions with single-stage φ = 10 mm miniature centrifugal contactor. The rotor's speed varies from 4000 r/min to 4500 r/min. The total throughput is less than 600 mL/h. the phase ratio(o/a) changes from 1/10 to 10/1. Under the above experimental conditions, the single contactor operates very well and gives good performance. The stage efficiencies of HNO 3 and Nd 3+ are about 90%. The Fe 3+ extraction is very slow kinetically and the stage efficiency of Fe 3+ is low

Novel highly integrated biodiesel production technology in a centrifugal contactor separator device

NARCIS (Netherlands)

Kraai, G. N.; Schuur, B.; van Zwol, F.; van de Bovenkamp, H. H.; Heeres, H. J.

2009-01-01

The base catalyzed production of biodiesel (FAME) from sunflower oil and methanol in a continuous centrifugal contactor separator (CCS) with integrated reaction and phase separation was studied. The effect of catalyst loading (sodium methoxide), temperature, rotational frequency and flow rates of

Relation between heat of vaporization, ion transport, molar volume, and cation-anion binding energy for ionic liquids.

Science.gov (United States)

Borodin, Oleg

2009-09-10

A number of correlations between heat of vaporization (H(vap)), cation-anion binding energy (E(+/-)), molar volume (V(m)), self-diffusion coefficient (D), and ionic conductivity for 29 ionic liquids have been investigated using molecular dynamics (MD) simulations that employed accurate and validated many-body polarizable force fields. A significant correlation between D and H(vap) has been found, while the best correlation was found for -log(DV(m)) vs H(vap) + 0.28E(+/-). A combination of enthalpy of vaporization and a fraction of the cation-anion binding energy was suggested as a measure of the effective cohesive energy for ionic liquids. A deviation of some ILs from the reported master curve is explained based upon ion packing and proposed diffusion pathways. No general correlations were found between the ion diffusion coefficient and molecular volume or the diffusion coefficient and cation/anion binding energy.

International Union of Theoretical and Applied Mechanics: Symposium on Adiabatic Waves in liquid-Vapor Systems Held at Goettingen (Germany, F.R.) on 28 August-1 September 1989. Abstracts of the Contributed Papers

Science.gov (United States)

1989-09-01

THE LIQUID- VAPOR CRITICAL POINT" P.A. Thompson, J.E. Shepherd, H.J. Cho, S.Can Gulen (Troy). Non-euilibrium in dinamic systems , critical phenomena...IN LIQUID-VAPOR SYSTEMS G~ttingen: 28. August - 1. September 1989 Chairmen: Gerd E.A. Meier & Philip A. Thompson Secretary: Tomasz A. Kowalewski...is a great pleasure to welcome you on behalf of the Organizing Committee to the IUTAM Symposium on Adiabatic Waves in Liquid Vapor Systems . We are

Experimental investigations on performance of liquid desiccant-vapor compression hybrid air conditioner

International Nuclear Information System (INIS)

Mohan, B. Shaji; Tiwari, Shaligram; Maiya, M.P.

2015-01-01

A coupled desiccant column is integrated with a conventional room air conditioner (AC) to enhance dehumidification of the room air. One desiccant column (absorber) is placed after the evaporator the other (regenerator) after the condenser of the AC unit. Such a novel liquid desiccant vapour compression hybrid air conditioning system has been fabricated and tested in a balanced ambient room type calorimeter for very low flow rates of liquid desiccant (lithium bromide solution). The moisture from the cold supply air is transferred to the hot condenser air by the desiccant flowing in the loop, thereby complimenting the dehumidification of the room air at the evaporator. The supply air is also sensibly heated during the dehumidification process by liquid desiccant in the absorber, which together enables the hybrid system to maintain low humidity in the room. Whereas the liquid desiccant is regenerated by the condenser waste heat, the entire cooling is derived only by the AC unit. The experimental results show that an increase of room temperature reduces both dehumidification of process air and regeneration of liquid desiccant, whereas an increase of room specific humidity enhances both these for the flow rate of the liquid desiccant in the range of 0.2–1.6% of the air flow rate through the absorber. - Highlights: • A liquid desiccant vapor compression hybrid system is fabricated and tested. • The liquid desiccant reduces latent load but equally increases sensible load. • Hybrid system performance is studied for varying room temperature and humidity. • Higher room temperature lowers air dehumidification and desiccant regeneration. • Increase of room specific humidity enhances dehumidification and also regeneration

Recovery of combustible vapors, by liquid refrigerated centrifugation, on distribution bases of loading islands; Recuperacao de vapores de combustiveis, por centrifugacao liquida refrigerada, em ilhas de carregamento das bases de distribuicao

Energy Technology Data Exchange (ETDEWEB)

Capulli, Domenico; Saraceno, Alessandra S.P. [Capmetal Tecnologia Ambiental, Rio de Janeiro, RJ (Brazil)

2004-07-01

The distribution of petroleum derivates organic combustibles represents, in volume, the second liquid fluid of the planet, with distribution basis, the loading operations of trucks, railroad coaches and vessels provokes the unfastening of volatile organic compounds - VOC, in Brazil the combustible vaporized fraction is estimated 313.308 liters daily, provoking health damages in operators and environmental impacts at aerial basin, determining the obligatory disposal of organic vapors capitation and depuration systems, with use of technologies, such as thermal oxidation, activated carbon adsorption, fluids absorptions and cryogenic condensation for treatment of the emanated vapors at loading operations, so the high aggregated value of the investment, the intensive consume of energy and the high sizes, that residue treatment units have postponed the investments in function of the missing of regularization in Brazil, counter pointing the regularization of the Clean Air Act and the United States Cost Guard that introduced the evolution and the availability of the BDT - Best Demonstrated Technologies - the technological innovation of the Hydrodynamic Precipitator operating by multi venturi liquid centrifugation married with refrigeration cycles that permit the recovery of the vapors and technologies BADCT - Best Demonstrated Control Technology - to viability the large extension of the compact control units required of smaller investment and one stage operation. (author)

Isobaric (vapor + liquid) equilibria for the ternary system of (ethanol + water + 1,3-propanediol) and three constituent binary systems at P = 101.3 kPa

International Nuclear Information System (INIS)

Lai, Hung-Sheng; Lin, Yi-Feng; Tu, Chein-Hsiun

2014-01-01

Highlights: • We report VLE data at 101.3 kPa for mixtures of ethanol, water, and 1,3-propanediol. • The VLE data were correlated by the Wilson, NRTL, and UNIQUAC models. • The ternary VLE data were predicted from binary VLE data using the three models. • The VLE effect of 1,3-propanediol on the azeotropic ethanol + water mixture was studied. • The azeotropic point of ethanol + water disappears at 30 wt% of 1,3-propanediol. -- Abstract: Isobaric (vapor + liquid) equilibrium (VLE) at P = 101.3 kPa have been measured for the ternary system of (ethanol + water + 1,3-propanediol) and for the corresponding binary systems of (ethanol + water), (ethanol + 1,3-propanediol), and (water + 1,3-propnaediol) using a Hunsmann-type equilibrium still with circulation of both vapor and liquid phases. The ternary mixtures were prepared by mixing ethanol and pure water with three concentrations (10, 30, and 50) wt% of 1,3-propanediol in the overall liquid mixtures in order to study the effect of 1,3-propanediol on the VLE of (ethanol + water). The equilibrium compositions of mixtures were analyzed by gas–liquid chromatography. The relative volatilities of ethanol with respect to water were also determined. The results of the investigation indicate the disappearance of the binary azeotrope between ethanol and water when the concentration of 1,3-propanediol is up to 30 wt%. The liquid activity coefficients were calculated using the modified Raoult’s law. The thermodynamic consistency of the VLE data was performed for the three binary systems using Van Ness direct test. The new binary and ternary VLE data were successfully correlated using the Wilson, NRTL, and UNIQUAC models, for which the binary interaction parameters are reported

Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

2011-01-01

Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 1. Vapor-liquid equilibria

DEFF Research Database (Denmark)

Grenner, Andreas; Tsivintzelis, Ioannis; Economou, Ioannis

2008-01-01

for the models were taken from literature or estimated in this work. Generalized pure-component parameters were fitted to pure-component vapor-pressure and liquid-density data. For the majority of the mixtures examined, satisfactory results were obtained. For a number of mixtures, different modeling approaches...... were applied to improve the results, such as incorporation of cross-association between nonself-associating fluids or induced association for mixtures of polar nonassociating and self-associating fluids. For both models, the overall deviations from experimental data are similar, and none of the models...

Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

Energy Technology Data Exchange (ETDEWEB)

Annenkova, E. A., E-mail: a-a-annenkova@yandex.ru [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Kreider, W. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States)

2015-10-28

Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

Effect of cooling rate on the survival of cryopreserved rooster sperm: Comparison of different distances in the vapor above the surface of the liquid nitrogen.

Science.gov (United States)

Madeddu, M; Mosca, F; Abdel Sayed, A; Zaniboni, L; Mangiagalli, M G; Colombo, E; Cerolini, S

2016-08-01

The aim of the present trial was to study the effect of different freezing rates on the survival of cryopreserved rooster semen packaged in straws. Slow and fast freezing rates were obtained keeping straws at different distances in the vapor above the surface of the nitrogen during freezing. Adult Lohmann roosters (n=27) were used. Two experiments were conducted. In Experiment 1, semen was packaged in straws and frozen comparing the distances of 1, 3 and 5cm in nitrogen vapor above the surface of the liquid nitrogen. In Experiment 2, the distances of 3, 7 and 10cm above the surfaces of the liquid nitrogen were compared. Sperm viability, motility and progressive motility and the kinetic variables were assessed in fresh and cryopreserved semen samples. The recovery rates after freezing/thawing were also calculated. In Experiment 1, there were no significant differences among treatments for all semen quality variables. In Experiment 2, the percentage of viable (46%) and motile (22%) sperm in cryopreserved semen was greater when semen was placed 3cm compared with 7 and 10cm in the vapor above the surface of the liquid nitrogen. The recovery rate of progressive motile sperm after thawing was also greater when semen was stored 3cm in the vapor above the surface of the liquid nitrogen. More rapid freezing rates are required to improve the survival of rooster sperm after cryopreservation and a range of distances from 1 to 5cm in nitrogen vapor above the surface of the liquid nitrogen is recommended for optimal sperm viability. Copyright © 2016 Elsevier B.V. All rights reserved.

MOLECULAR SIMULATION OF THE VAPOR-LIQUID EQUILIBRIUM OF N2-NC5 MIXTURE BY MONTE CARLO SIMULATIONS

Directory of Open Access Journals (Sweden)

Florianne Castillo-Borja

2013-12-01

Full Text Available ABSTRACT This study used Monte Carlo simulations in the Gibbs ensemble to describe the liquid-vapor phase equilibrium of nitrogen-n-pentane system for three isotherms. The study analyzed a wide range of pressures ranging up to 25 MPa. The system was modeled using the intermolecular potential Galassi-Tildesley for nitrogen and SKS for n-pentane. Results were compared against experimental data. Far from the critical point region, analyzed models reproduce favorably shape of the curve of phase equilibrium and in the vicinity of the critical point, results tend to move away from the experimental behavior. Critical points were determined (pressure, density and composition for the three isotherms using an extrapolation method based on scaling laws, with satisfactory results. Calculated coexistence curves are adequate even if the models analyzed do not contain optimized binary interaction parameters .

A computational model of a PEM fuel cell with finite vapor absorption rate

Energy Technology Data Exchange (ETDEWEB)

Vorobev, A.; Zikanov, O.; Shamim, T. [Department of Mechanical Engineering, University of Michigan-Dearborn, 48128-1491 Dearborn, MI (United States)

2007-03-30

The paper presents a new computational model of non-steady operation of a PEM fuel cell. The model is based on the macroscopic hydrodynamic approach and assumptions of low humidity operation and one-dimensionality of transport processes. Its novelty and advantage in comparison with similar existing models is that it takes into account the finite-time equilibration between vapor and membrane-phase liquid water within the catalyst layers. The phenomenon is described using an additional parameter with the physical meaning of the typical reciprocal time of the equilibration. A computational parametric study is conducted to identify the effect of the finite-time equilibration on steady-state and transient operation of a PEM fuel cell. (author)

Effect of Feed Gas Flow Rate on CO2 Absorption through Super Hydrophobic Hollow Fiber membrane Contactor

Science.gov (United States)

Kartohardjono, Sutrasno; Alexander, Kevin; Larasati, Annisa; Sihombing, Ivander Christian

2018-03-01

Carbon dioxide is pollutant in natural gas that could reduce the heating value of the natural gas and cause problem in transportation due to corrosive to the pipeline. This study aims to evaluate the effects of feed gas flow rate on CO2 absorption through super hydrophobic hollow fiber contactor. Polyethyleneglycol-300 (PEG-300) solution was used as absorbent in this study, whilst the feed gas used in the experiment was a mixture of 30% CO2 and 70% CH4. There are three super hydrophobic hollow fiber contactors sized 6 cm and 25 cm in diameter and length used in this study, which consists of 1000, 3000 and 5000 fibers, respectively. The super hydrophobic fiber membrane used is polypropylene-based with outer and inner diameter of about 525 and 235 μm, respectively. In the experiments, the feed gas was sent through the shell side of the membrane contactor, whilst the absorbent solution was pumped through the lumen fibers. The experimental results showed that the mass transfer coefficient, flux, absorption efficiency for CO2-N2 system and CO2 loading increased with the feed gas flow rate, but the absorption efficiency for CO2-N2 system decreased. The mass transfer coefficient and the flux, at the same feed gas flow rate, decreased with the number of fibers in the membrane contactor, but the CO2 absorption efficiency and the CO2 loading increased.

Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

Energy Technology Data Exchange (ETDEWEB)

Herman, D. T.; Duignan, M. R.; Williams, M. R.; Peters, T. B.; Poirier, M. R.; Fondeur, F. F.

2013-07-31

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05 M) concentration of the MaxCalix as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the “first stage” D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet

Experimental and modelling studies on continuous synthesis and refining of biodiesel in a dedicated bench scale unit using centrifugal contactor separator technology

NARCIS (Netherlands)

Abduh, Muhammad Yusuf; Martinez, Alberto Fernandez; Kloekhorst, Arjan; Manurung, Robert; Heeres, Hero J.

Continuous synthesis and refining of biodiesel (FAME) using a laboratory scale bench scale unit was explored. The unit consists of three major parts: (i) a continuous centrifugal contactor separator (CCCS) to perform the reaction between sunflower oil and methanol; (ii) a washing unit for the crude

Dynamics of a microbial biofilm in a rotating biological contactor for ...

African Journals Online (AJOL)

Wastewater from wine-related industries is characterised by high variability in COD and pH. Disposal of these effluents with little or no treatment could lead to heavy financial penalties or pollution of soil and water resources. A pilot-scale rotating biological contactor (RBC) was evaluated for the treatment of winery effluent, ...

Vapor-liquid Phase Equilibria for CO2+Tertpentanol Binary System at Elevated Pressures

Institute of Scientific and Technical Information of China (English)

WANG Lin; LUO Jian-cheng; YANG Hao; CHEN Kai-xun

2011-01-01

Vapor-liquid phase equilibrium data of tertpentanol in carbon dioxide were measured at temperatures of 313.4,323.4,333.5 and 343.5 K and in the pressure range of 4.56-11.44 MPa.The phase equilibium apparatus used in the work was a variable-volume high-pressure cell.The experimental data were reasonably correlated with Peng-Robinson equation of state(PR-EOS) together with van der Waals-2 two-parameter mixing rules.Henry's Law constants and partial molar volumes of CO2 at infinite dilution were estimated with Krichevsky-Kasarnovsky equation,and Henry's Law constants increase with increasing temperature,however,partial molar volumes of CO2 at infinite dilution are negative whose magnitudes decrease with temperature.Partial molar volumes of CO2 and tertpentanol in liquid phase at equilibrium were calculated.

Insights into Mechanistic Models for Evaporation of Organic Liquids in the Environment Obtained by Position-Specific Carbon Isotope Analysis.

Science.gov (United States)

Julien, Maxime; Nun, Pierrick; Robins, Richard J; Remaud, Gérald S; Parinet, Julien; Höhener, Patrick

2015-11-03

Position-specific isotope effects (PSIEs) have been measured by isotope ratio monitoring (13)C nuclear magnetic resonance spectrometry during the evaporation of 10 liquids of different polarities under 4 evaporation modes (passive evaporation, air-vented evaporation, low pressure evaporation, distillation). The observed effects are used to assess the validity of the Craig-Gordon isotope model for organic liquids. For seven liquids the overall isotope effect (IE) includes a vapor-liquid contribution that is strongly position-specific in polar compounds but less so in apolar compounds and a diffusive IE that is not position-specific, except in the alcohols, ethanol and propan-1-ol. The diffusive IE is diminished under forced evaporation. The position-specific isotope pattern created by liquid-vapor IEs is manifest in five liquids, which have an air-side limitation for volatilization. For the alcohols, undefined processes in the liquid phase create additional PSIEs. Three other liquids with limitations on the liquid side have a lower, highly position-specific, bulk diffusive IE. It is concluded that evaporation of organic pollutants creates unique position-specific isotope patterns that may be used to assess the progress of remediation or natural attenuation of pollution and that the Craig-Gordon isotope model is valid for the volatilization of nonpolar organic liquids with air-side limitation of the volatilization rate.

Computational Fluid Dynamics Model for Saltstone Vault 4 Vapor Space

International Nuclear Information System (INIS)

Lee, Si Young

2005-01-01

Computational fluid dynamics (CFD) methods have been used to estimate the flow patterns for vapor space inside the Saltstone Vault No.4 under different operating scenarios. The purpose of this work is to examine the gas motions inside the vapor space under the current vault configurations. A CFD model took three-dimensional transient momentum-energy coupled approach for the vapor space domain of the vault. The modeling calculations were based on prototypic vault geometry and expected normal operating conditions as defined by Waste Solidification Engineering. The modeling analysis was focused on the air flow patterns near the ventilated corner zones of the vapor space inside the Saltstone vault. The turbulence behavior and natural convection mechanism used in the present model were benchmarked against the literature information and theoretical results. The verified model was applied to the Saltstone vault geometry for the transient assessment of the air flow patterns inside the vapor space of the vault region using the boundary conditions as provided by the customer. The present model considered two cases for the estimations of the flow patterns within the vapor space. One is the reference baseline case. The other is for the negative temperature gradient between the roof inner and top grout surface temperatures intended for the potential bounding condition. The flow patterns of the vapor space calculated by the CFD model demonstrate that the ambient air comes into the vapor space of the vault through the lower-end ventilation hole, and it gets heated up by the Benard-cell type circulation before leaving the vault via the higher-end ventilation hole. The calculated results are consistent with the literature information

Melting temperature, vapor density, and vapor pressure of molybdenum pentafluoride

Energy Technology Data Exchange (ETDEWEB)

Krause, Jr, R F; Douglas, T B [National Bureau of Standards, Washington, D.C. (USA). Inst. for Materials Research

1977-12-01

A sample of MoF/sub 5/ was prepared by reaction of MoF/sub 6/(g) and Mo(c). Melting curves of temperature against time established the melting temperature at zero impurity to be 318.85 K, the enthalpy of fusion to be 6.1 kJ mol/sup -1/ (+ - 5 per cent), and the cryoscopic impurity of the sample to be 0.15 mole per cent. In the presence of MoF/sub 6/(g) which was added to suppress disproportionation, the vapor density of MoF/sub 5/ over the liquid was measured by the transpiration method at 343, 363, and 383 K, the total MoF/sub 5/ that evaporated being determined by permanganate titration. The total vapor pressure of MoF/sub 5/ oligomers over the liquid was measured by a simple static method at 373 and 392 K, while melting temperatures were taken alternately to monitor possible contamination of the sample. Although the vapor pressures were adjusted for disproportionation, solution of MoF/sub 6/ in MoF/sub 5/ (1), and wall adsorption of MoF/sub 6/ their percentage uncertainty is probably several times that of the vapor densities. A combination of the two properties indicates the average extent of association of the saturated vapor to be near 2, which is the value for the dimer species (MoF/sub 5/)/sub 2/.

Problems of hydrogen - water vapor - inert gas mixture use in heavy liquid metal coolant technology

International Nuclear Information System (INIS)

Ul'yanov, V.V.; Martynov, P.N.; Gulevskij, V.A.; Teplyakov, Yu.A.; Fomin, A.S.

2014-01-01

The reasons of slag deposit formation in circulation circuits with heavy liquid metal coolants, which can cause reactor core blockage, are considered. To prevent formation of deposits hydrogen purification of coolant and surfaces of circulation circuit is used. It consists in introduction of gaseous mixtures hydrogen - water vapor - rare gas (argon or helium) directly into coolant flow. The principle scheme of hydrogen purification and the processes occurring during it are under consideration. Measures which make it completely impossible to overlap of the flow cross section of reactor core, steam generators, pumps and other equipment by lead oxides in reactor facilities with heavy liquid metal coolants are listed [ru

Liquid nitrogen vapor is comparable to liquid nitrogen for storage of cryopreserved human sperm: evidence from the characteristics of post-thaw human sperm.

Science.gov (United States)

Hu, Jingmei; Zhao, Shidou; Xu, Chengyan; Zhang, Lin; Lu, Shaoming; Cui, Linlin; Ma, Jinlong; Chen, Zi-Jiang

2015-11-01

To compare the differences in the characteristics of post-thaw human sperm after storage in either liquid nitrogen (LN2; -196 °C) or LN2 vapor (-167 °C). Experimental study. University hospital. Thirty healthy volunteers who agreed to donate their normal semen samples for infertility or research were included in the study. Semen samples (n = 30) were divided into eight aliquots and frozen. Four aliquots of each human semen sample were stored in LN2 (-196 °C), and the other four aliquots were stored in LN2 vapor (-167 °C). After 1, 3, 6, or 12 months, samples were thawed and analyzed. The motility was evaluated by the manual counting method. The viability was estimated by eosin staining. The morphology was analyzed by Diff-Quik staining. The sperm DNA integrity was determined with acridine orange fluorescent staining, and acrosin activity was assayed by the modified Kennedy method. The characteristics of post-thaw human sperm, including motility, viability, morphology, DNA integrity, and acrosin activity, showed no significant difference between LN2 and LN2 vapor storage for the different time periods. LN2 vapor was comparable to LN2 in post-thaw sperm characteristics, suggesting that LN2 vapor may be substituted for LN2 for the long-term storage of human sperm. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Hydraulic performance of a multistage array of advanced centrifugal contactors

International Nuclear Information System (INIS)

Hodges, M.E.

1984-01-01

The hydraulic characteristics of an advanced design centrifugal contactor array have been determined at the Savannah River Laboratory (SRL). The advanced design utilizes couette mixing (Taylor vortices) in the annulus between the rotating and stationary bowls. Excellent phase separation over a wide range of flow conditions was obtained. Interfaces within an entire eight-stage array were controlled with a single weir air pressure. 2 references, 5 figures

Fabrication and performance evaluation of a high temperature co-fired ceramic vaporizing liquid microthruster

International Nuclear Information System (INIS)

Cheah, Kean How; Low, Kay-Soon

2015-01-01

This paper presents the study of a microelectromechanical system (MEMS)-scaled microthruster using ceramic as the structural material. A vaporizing liquid microthruster (VLM) has been fabricated using the high temperature co-fired ceramic (HTCC) technology. The developed microthruster consists of five components, i.e. inlet, injector, vaporizing chamber, micronozzle and microheater, all integrated in a chip with a dimension of 30 mm × 26 mm × 8 mm. In the dry test, the newly developed microheater which is deposited on zirconia substrate consumes 21% less electrical power than those deposited on silicon substrate to achieve a temperature of 100 °C. Heating temperature as high as 409.1 °C can be achieved using just 5 W of electrical power. For simplicity and safety, a functional test of the VLM with water as propellant has been conducted in the laboratory. Full vaporization of water propellant feeding at different flow rates has been successfully demonstrated. A maximum thrust of 633.5 µN at 1 µl s −1 propellant consumption rate was measured using a torsional thrust stand. (paper)

Experimental determination of the (vapor + liquid) equilibrium data of binary mixtures of fatty acids by differential scanning calorimetry

International Nuclear Information System (INIS)

Matricarde Falleiro, Rafael M.; Meirelles, Antonio J.A.; Kraehenbuehl, Maria A.

2010-01-01

(Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (φ = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C 14:0 ) + palmitic acid (C 16:0 ), myristic acid (C 14:0 ) + stearic acid (C 18:0 ), and palmitic acid (C 16:0 ) + stearic acid (C 18:0 ), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g E models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.

Performance of polydimethylsiloxane membrane contactor process for selective hydrogen sulfide removal from biogas.

Science.gov (United States)

Tilahun, Ebrahim; Bayrakdar, Alper; Sahinkaya, Erkan; Çalli, Bariş

2017-03-01

H 2 S in biogas affects the co-generation performance adversely by corroding some critical components within the engine and it has to be removed in order to improve the biogas quality. This work presents the use of polydimethylsiloxane (PDMS) membrane contactor for selective removal of H 2 S from the biogas. Experiments were carried out to evaluate the effects of different pH of absorption liquid, biogas flowrate and temperature on the absorption performances. The results revealed that at the lowest loading rate (91mg H 2 S/m 2 ·h) more than 98% H 2 S and 59% CO 2 absorption efficiencies were achieved. The CH 4 content in the treated gas increased from 60 to 80% with nearly 5% CH 4 loss. Increasing the pH (7-10) and loading rate (91-355mg H 2 S/m 2 ·h) enhanced the H 2 S absorption capacity, and the maximum H 2 S/CO 2 and H 2 S/CH 4 selectivity factors were 2.5 and 58, respectively. Temperature played a key role in the process and lower temperature was beneficial for intensifying H 2 S absorption performance. The highest H 2 S fluxes at pH 10 and 7 were 3.4g/m 2 ·d and 1.8g/m 2 ·d with overall mass transfer coefficients of 6.91×10 -6 and 4.99×10 -6 m/s, respectively. The results showed that moderately high H 2 S fluxes with low CH 4 loss may be achieved by using a robust and cost-effective membrane based absorption process for desulfurization of biogas. A tubular PDMS membrane contactor was tested for the first time to remove H 2 S from biogas under slightly alkaline conditions and the suggested process could be a promising for real scale applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Migration of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling

Directory of Open Access Journals (Sweden)

Peng Hao

2011-01-01

Full Text Available Abstract The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt.%, the heat flux is from 10 to 100 kW·m-2, and the initial liquid-level height is from 1.3 to 3.4 cm. The experimental results indicate that the migration ratio of carbon nanotube increases with the increase of the outside diameter or the length of carbon nanotube. For the fixed type of carbon nanotube, the migration ratio decreases with the increase of the oil concentration or the heat flux, and increases with the increase of the initial liquid-level height. The migration ratio of carbon nanotube increases with the decrease of dynamic viscosity of refrigerant or the increase of liquid phase density of refrigerant. A model for predicting the migration ratio of carbon nanotubes in the refrigerant-based nanofluid pool boiling is proposed, and the predictions agree with 92% of the experimental data within a deviation of ±20%.

Fuel Evaporation in an Atmospheric Premixed Burner: Sensitivity Analysis and Spray Vaporization

Directory of Open Access Journals (Sweden)

Dávid Csemány

2017-12-01

Full Text Available Calculation of evaporation requires accurate thermophysical properties of the liquid. Such data are well-known for conventional fossil fuels. In contrast, e.g., thermal conductivity or dynamic viscosity of the fuel vapor are rarely available for modern liquid fuels. To overcome this problem, molecular models can be used. Currently, the measurement-based properties of n-heptane and diesel oil are compared with estimated values, using the state-of-the-art molecular models to derive the temperature-dependent material properties. Then their effect on droplet evaporation was evaluated. The critical parameters were liquid density, latent heat of vaporization, boiling temperature, and vapor thermal conductivity where the estimation affected the evaporation time notably. Besides a general sensitivity analysis, evaporation modeling in a practical burner ended up with similar results. By calculating droplet motion, the evaporation number, the evaporation-to-residence time ratio can be derived. An empirical cumulative distribution function is used for the spray of the analyzed burner to evaluate evaporation in the mixing tube. Evaporation number did not exceed 0.4, meaning a full evaporation prior to reaching the burner lip in all cases. As droplet inertia depends upon its size, the residence time has a minimum value due to the phenomenon of overshooting.

Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C1-C4) and dimethyl carbonate

International Nuclear Information System (INIS)

Matsuda, Hiroyuki; Fukano, Makoto; Kikkawa, Shinichiro; Constantinescu, Dana; Kurihara, Kiyofumi; Tochigi, Katsumi; Ochi, Kenji; Gmehling, Juergen

2012-01-01

Highlights: → The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. → VLE data for ternary and binary mixtures containing alcohol and DMC were measured. → Several activity coefficient models were used for data reduction or prediction. → Valley line, i.e., distillation boundary, was observed for the ternary mixture. → Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {methanol + propan-1-ol + dimethyl carbonate (DMC)}, and four binary mixtures, namely an {alcohol (C 3 or C 4 ) + DMC}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

Thermally activated vapor bubble nucleation: The Landau-Lifshitz-Van der Waals approach

Science.gov (United States)

Gallo, Mirko; Magaletti, Francesco; Casciola, Carlo Massimo

2018-05-01

Vapor bubbles are formed in liquids by two mechanisms: evaporation (temperature above the boiling threshold) and cavitation (pressure below the vapor pressure). The liquid resists in these metastable (overheating and tensile, respectively) states for a long time since bubble nucleation is an activated process that needs to surmount the free energy barrier separating the liquid and the vapor states. The bubble nucleation rate is difficult to assess and, typically, only for extremely small systems treated at an atomistic level of detail. In this work a powerful approach, based on a continuum diffuse interface modeling of the two-phase fluid embedded with thermal fluctuations (fluctuating hydrodynamics), is exploited to study the nucleation process in homogeneous conditions, evaluating the bubble nucleation rates and following the long-term dynamics of the metastable system, up to the bubble coalescence and expansion stages. In comparison with more classical approaches, this methodology allows us on the one hand to deal with much larger systems observed for a much longer time than possible with even the most advanced atomistic models. On the other, it extends continuum formulations to thermally activated processes, impossible to deal with in a purely determinist setting.

Solid and Liquid Waste Drying Bag

Science.gov (United States)

Litwiller, Eric (Inventor); Hogan, John A. (Inventor); Fisher, John W. (Inventor)

2009-01-01

Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.

Final report on the small-scale vapor-explosion experiments using a molten NaCl--H2O system

International Nuclear Information System (INIS)

Anderson, R.P.; Bova, L.

1976-04-01

Vapor explosions were produced by injecting small quantities of water into a container filled with molten NaCl. Minimum explosion efficiencies, as evaluated from reaction-impulse measurements, were relatively large. Subsurface movies showed that the explosions resulted from a two-step sequence: an initial bulk-mixing phase in which the two liquids intermix on a large scale, but remain locally separated by an insulating gas-vapor layer; and a second step, immediately following breakdown of the gas layer, during which the two liquids locally fragment, intermix, and pressurize very rapidly. The experimental results were compared with various mechanistic models that had been proposed to explain vapor explosions. Early models seemed inconsistent with the results. More recent theories suggest that vapor explosions may be caused by a nucleation limit or by dynamic mixing combined with high surface-heat-transfer rates. Both types of models are consistent with the results

HIGH PRESSURE VAPOR-LIQUID EQUILIBRIA OF PALM FATTY ACIDS DISTILLATES-CARBON DIOXIDE SYSTEM

Directory of Open Access Journals (Sweden)

Nélio T. MACHADO

1997-12-01

Full Text Available Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid and unsaturated (oleic+linoleic acids fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.Foi investigado experimentalmente o equilíbrio líquido-vapor para o sistema Destilado Ácido de Óleo de Palma (PFAD/Dióxido de Carbono, nas temperaturas de 333, 353 e 373 K e pressões de 20, 23, 26 e 29 MPa, usando-se o método estático. Os dados experimentais do sistema pseudo-binário PFAD/CO2 foram correlacionados com a equação de estado de Redlich-Kwong do pacote computacional ASPEN. O modelo reproduz bem os resultados experimentais. A seletividade obtida indica que o CO2 supercrítico é um solvente razoável para a separação em coluna multi-estágio e contínua, do ácido graxo saturado (ácido palmítico daqueles insaturados (ácido oleico e ácido linoleico contidos no PFAD.

Isothermal Vapor-Liquid Equilibrium in the Quaternary Water + 2-Propanol + Acetic Acid + Isopropyl Acetate System with Chemical Reaction

Czech Academy of Sciences Publication Activity Database

Teodorescu, M.; Aim, Karel; Wichterle, Ivan

2001-01-01

Roč. 46, č. 2 (2001), s. 261-266 ISSN 0021-9568 R&D Projects: GA ČR GA203/98/1446 Institutional research plan: CEZ:AV0Z4072921 Keywords : vapor-liquid equilibrium * quaternary water Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.960, year: 2001

Sustainable in-well vapor stripping: A design, analytical model, and pilot study for groundwater remediation

Science.gov (United States)

Sutton, Patrick T.; Ginn, Timothy R.

2014-12-01

A sustainable in-well vapor stripping system is designed as a cost-effective alternative for remediation of shallow chlorinated solvent groundwater plumes. A solar-powered air compressor is used to inject air bubbles into a monitoring well to strip volatile organic compounds from a liquid to vapor phase while simultaneously inducing groundwater circulation around the well screen. An analytical model of the remediation process is developed to estimate contaminant mass flow and removal rates. The model was calibrated based on a one-day pilot study conducted in an existing monitoring well at a former dry cleaning site. According to the model, induced groundwater circulation at the study site increased the contaminant mass flow rate into the well by approximately two orders of magnitude relative to ambient conditions. Modeled estimates for 5 h of pulsed air injection per day at the pilot study site indicated that the average effluent concentrations of dissolved tetrachloroethylene and trichloroethylene can be reduced by over 90% relative to the ambient concentrations. The results indicate that the system could be used cost-effectively as either a single- or multi-well point technology to substantially reduce the mass of dissolved chlorinated solvents in groundwater.

HIGH-PRESSURE VAPOR-LIQUID EQUILIBRIUM DATA FOR BINARY AND TERNARY SYSTEMS FORMED BY SUPERCRITICAL CO2, LIMONENE AND LINALOOL

Directory of Open Access Journals (Sweden)

MELO S. A. B. VIEIRA DE

1999-01-01

Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

Ionic liquids. Combination of combustion calorimetry with high-level quantum chemical calculations for deriving vaporization enthalpies.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas; Schick, Christoph

2008-07-10

In this work, the molar enthalpies of formation of the ionic liquids [C2MIM][NO3] and [C4MIM][NO3] were measured by means of combustion calorimetry. The molar enthalpy of fusion of [C2MIM][NO3] was measured using differential scanning calorimetry. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the G3MP2 theory. We have used a combination of traditional combustion calorimetry with modern high-level ab initio calculations in order to obtain the molar enthalpies of vaporization of a series of the ionic liquids under study.

Uptake of mercury vapor by wheat. An assimilation model

International Nuclear Information System (INIS)

Browne, C.L.; Fang, S.C.

1978-01-01

Using a whole-plant chamber and 203 Hg-labeled mercury, a quantitative study was made of the effect of environmental parameters on the uptake, by wheat (Triticum aestivum), of metallic mercury vapor, an atmospheric pollutant. Factors were examined in relation to their influence on components of the gas-assimilation model, U(Hg) = (C/sub A' -- C/sub L')/(r/sub L.Hg/ + r/sub M.Hg/) where U(Hg) is the rate of mercury uptake per unit leaf surface, C/sub A'/ is the ambient mercury vapor concentration, C/sub L'/ is the mercury concentration at immobilization sites within the plant (assumed to be zero), r/sub L.Hg/ is the total leaf resistance to mercury vapor exchange, and r/sub M.Hg/ is a residual term to account for unexplained physical and biochemical resistances to mercury vapor uptake. Essentially all mercury vapor uptake was confined to the leaves. r/sub L.Hg/ was particularly influenced by illumination (0 to 12.8 klux), but unaffected by ambient temperature (17 to 33 0 C) and mercury vapor concentration (0 to 40 μg m -3 ). The principal limitation to mercury vapor uptake was r/sub M.Hg/, which was linearly related to leaf temperature, but unaffected by mercury vapor concentration and illumination, except for apparent high values in darkness. Knowing C/sub A'/ and estimating r/sub L.Hg/ and r/sub M.Hg/ from experimental data, mercury vapor uptake by wheat in light was accurately predicted for several durations of exposure using the above model

Nuclear material inventory estimation in solvent extraction contactors III. Final report for the period 1 January 1988 - 28 February 1989

International Nuclear Information System (INIS)

Beyerlein, A.L.; Geldard, J.F.

1989-03-01

Simple mathematical models have been developed for estimating the nuclear material inventory in the solvent extraction contactors of nuclear fuel reprocessing facilities from measured nuclear material concentrations in the tanks feeding the purification cycles. The report describes the models and their application to the Eurochemic Reprocessing Plant in Belgium, and the development of a computer simulation program, PUPART, for investigating the effects of process variation as well as measurement error on near-real-time accounting methods. Figs and tabs

Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature.

Science.gov (United States)

Chapela, Gustavo A; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

2015-04-21

A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

Operating experience of centrifugal contactors used in a third plutonium purification cycle at the Marcoule reprocessing plant

International Nuclear Information System (INIS)

Coste, J.A.; Breschet, C.A.; Delafontaine, G.L.

1991-01-01

Multistage centrifugal contactors of the type SGN-ROBATEL LX 208 NSC are used in a third plutonium cycle at the Marcoule Reprocessing Plant, they have been smooth-running since the commissioning in 1984. The four centrifugal contactors, totalling 32 stages, are used for Extraction. Scrub and Acidic Strip, and a bank of three flat mixer-settlers is used for plutonium blocking, and soda washing of the solvent. The plutonium product, the residual activity of which is less than one microcurie per gram, is diluent washed in a bank of three flat mixer-settlers, before been concentrated in a zirconium evaporator to 200 g. 1 -1

LEGAL PROTECTION FOR CONSUMER OF UNLICENCED VAPOR FROM DRUG AND FOOD SUPERVISORY AGENCY

Directory of Open Access Journals (Sweden)

Dedhi Bima Samudra

2018-04-01

Full Text Available Abstract This research begins with the number of liquid vapor that is not licensed BPOM spread in Indonesia, and there is no clear law for liquid vapor, so there is no clarity from legal protection against liquid vapor consumers who are not licensed from  BPOM. Therefore, in this research, there is the formulation of the problem as follows: Is there a legal protection against liquid vapor consumers who are not licensed from BPOM?. The purpose of this research to determine whether there is legal protection against liquid vapor consumers who are not licensed BPOM. So this research can be useful for subsequent research that has the same theme and beneficial to researchers, liquid vapor consumers and also for the government. The research method used is the normative method. Normative research methods using statute approach. The result of the research shows that there is legal protection for liquid vapor consumer who is not licensed by BPOM, which is reviewed from the Law of the Republic of Indonesia Number 36 Year on concerning the health of Article 113 paragraph (1 and Article 114, Law of the Republic of Indonesia Number 8 Year 1999 on Consumer protection Article 8 paragraph (1 c and paragraph (1 i, Regulation of the Head of the Food and Drug Supervisory Agency of the Republic of Indonesia Number 4 Year 2017 on the Supervision of the Importation of Drugs into the Territory of Indonesia Article 4 paragraph (1. Keywords: Legal Protection, Consumer, Liquid-Vapor

Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

International Nuclear Information System (INIS)

Herman, D. T.; Duignan, M. R.; Williams, M. R.; Peters, T. B.; Poirier, M. R.; Fondeur, F. F.

2013-01-01

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05 M) concentration of the MaxCalix as well as a new suppressor, tris(3,7 dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the ''first stage'' D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet

Study of the Vapor-Liquid Coexistence Curve and the Critical Curve for Nonazeotropic Refrigerant Mixture R152a + R114 System

Science.gov (United States)

Kabata, Yasuo; Higashi, Yukihiro; Uematsu, Masahiko; Watanabe, Koichi

Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of R152a (CH3CHF2: 1, l-difluoroethane) +R 114 (CCIF2CCIF2 :1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Forty-eight saturated densities along the vapor-liquid coexistence curve between 204 and 861 kg·m-3 for five different compositions of 10, 20, 50, 80 and 90 wt% R 152a were obtained in the temperature range 370 to 409 K. The experimental errors of temperature, density, and mass fraction were estimated within ±10mK, ±0.5% and +0.05 %, respectively. On the basis of these measurements, the critical parameters of five different compositions for the R 152a +R 114 system were determined in consideration of the meniscus disappearance level as well as intensity of the critical opalescence. In accordance with the previous results of three other refrigerant mixtures, i.e., R 12 +R 22 system, R 22 +R 114 system and R 13B1 + R 114 system, the coexistence curve and critical curve on the temperature-density diagram for binary refrigerant mixtures were discussed. In addition, correlations of its composition dependence for this system were proposed.

Measurement and correlation of (vapor + liquid) equilibrium data for {α-pinene + p-cymene + (S)-(−)-limonene} ternary system at atmospheric pressure

International Nuclear Information System (INIS)

Sun, Lixia; Liao, Dankui; Yang, Zhengyu; Chen, Xiaopeng; Tong, Zhangfa

2013-01-01

Highlights: ► The VLE data of (α-pinene + p-cymene) and (α-pinene + p-cymene + (S)-(−)-limonene) at atmospheric pressure were measured. ► The VLE data of binary system were correlated by four activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the Liebermann–Fried model. ► The constant G 123 E counters plotted on the Roozeboom diagrams. -- Abstract: (Vapor + liquid) equilibrium (VLE) data for binary system of (α-pinene + p-cymene) and ternary system of {α-pinene + p-cymene + (S)-(−)-limonene} were measured at 100.7 kPa using the modified Ellis equilibrium still. The VLE data are thermodynamically consistent. Parameters of the binary system for the four solution models — Liebermann–Fried, Wilson, NRTL, and UNIQUAC — were calculated by referencing least squares method to minimize an objective function based on the total pressure. The ternary system data were predicted with the parameters of Liebermann–Fried model obtained from the pertinent binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results. Smooth representations of the results are used to construct constant excess Gibbs free energy contours on Roozeboom diagrams

Separation coefficients of liquid-vapor in systems formed by yttrium chloride with some impurities

International Nuclear Information System (INIS)

Volkov, V.T.; Nikiforova, T.V.; Nisel'son, L.A.; Telegin, G.F.

1990-01-01

Using equilibrium Rayleigh distillation in the 800-950 deg C temperature range, separation coefficients of liquid-vapor for systems, formed by yttrium chloride with Co, Cr, Ni, Mn, Fe, Cu, Na, K, Mg, Ca, Li impurities are determined. The impurity concentration lies within 0.02-0.4 mass. % limits of each impurity, and total impurity concentration does not exceed 1 mass. %. The tested impurities, except for calcium, are more volatile than the base, yttrium trichloride. In most systems negative deviation from the Raoult's law is observed

ISS And Space Environment Interactions Without Operating Plasma Contactor

Science.gov (United States)

Carruth, M. R., Jr.; Ferguson, Dale; Suggs,Rob; McCollum, Matt

2001-01-01

The International Space Station (ISS) will be the largest, highest power spacecraft placed in orbit. Because of this the design of the electrical power system diverged markedly from previous systems. The solar arrays will operate at 160 V and the power distribution voltage will be 120 V. The structure is grounded to the negative side of the solar arrays so under the right circumstances it is possible to drive the ISS potential very negative. A plasma contactor has been added to the ISS to provide control of the ISS structure potential relative to the ambient plasma. The ISS requirement is that the ISS structure not be greater than 40 V positive or negative of local plasma. What are the ramifications of operating large structures with such high voltage power systems? The application of a plasma contactor on ISS controls the potential between the structure and the local plasma, preventing degrading effects. It is conceivable that there can be situations where the plasma contactor might be non-functional. This might be due to lack of power, the need to turn it off during some of the build-up sequences, the loss of functionality for both plasma contactors before a replacement can be installed, similar circumstances. A study was undertaken to understand how important it is to have the contactor functioning and how long it might be off before unacceptable degradation to ISS could occur. The details of interaction effects on spacecraft have not been addressed until driven by design. This was true for ISS. If the structure is allowed to float highly negative impinging ions can sputter exposed conductors which can degrade the primary surface and also generate contamination due to the sputtered material. Arcing has been known to occur on solar arrays that float negative of the ambient plasma. This can also generate electromagnetic interference and voltage transients. Much of the ISS structure and pressure module surfaces exposed to space is anodized aluminum. The anodization

Vapor-droplet flow equations

International Nuclear Information System (INIS)

Crowe, C.T.

1975-01-01

General features of a vapor-droplet flow are discussed and the equations expressing the conservation of mass, momentum, and energy for the vapor, liquid, and mixture using the control volume approach are derived. The phenomenological laws describing the exchange of mass, momentum, and energy between phases are also reviewed. The results have application to development of water-dominated geothermal resources

Vapor condensation device

International Nuclear Information System (INIS)

Sakurai, Manabu; Hirayama, Fumio; Kurosawa, Setsumi; Yoshikawa, Jun; Hosaka, Seiichi.

1992-01-01

The present invention enables to separate and remove 14 C as CO 3 - ions without condensation in a vapor condensation can of a nuclear facility. That is, the vapor condensation device of the nuclear facility comprises (1) a spray pipe for spraying an acidic aqueous solution to the evaporation surface of an evaporation section, (2) a spray pump for sending the acidic aqueous solution to the spray pipe, (3) a tank for storing the acidic aqueous solution, (4) a pH sensor for detecting pH of the evaporation section, (5) a pH control section for controlling the spray pump, depending on the result of the detection of the pH sensor. With such a constitution, the pH of liquid wastes on the vaporization surface is controlled to 7 by spraying an aqueous solution of dilute sulfuric acid to the evaporation surface, thereby enabling to increase the transfer rate of 14 C to condensates to 60 to 70%. If 14 C is separated and removed as a CO 2 gas from the evaporation surface, the pH of the liquid wastes returns to the alkaline range of 9 to 10 and the liquid wastes are returned to a heating section. The amount of spraying the aqueous solution of dilute sulfuric acid can be controlled till the pH is reduced to 5. (I.S.)

Comparison of molecular models of carbon monoxide for calculation of vapor-liquid equilibrium

Directory of Open Access Journals (Sweden)

Bibian Alonso Hoyos-Madrigal

2015-01-01

Full Text Available Existen varios modelos moleculares para el monóxido de carbono desarrollados a partir de diferentes mediciones experimentales. El objetivo de este trabajo es comparar los resultados que varios de estos modelos producen en el cálculo del equilibrio líquido-vapor en busca de recomendar qué modelo debe ser usado de acuerdo la propiedad y la fase que se desea calcular. Los modelos seleccionados corresponden a cuatro modelos no polares, con uno o dos sitios Lennard-Jones, y cuatro modelos polares, con dipolos o cargas parciales para representar la polaridad del monóxido de carbono. Simulaciones Monte Carlo en la versión Gibbs canónica (NVT-GEMC se emplearon para determinar las densidades de las fases en equilibrio, la presión de vapor y la entalpia de vaporización entre 80 y 130 K con cada uno de los modelos seleccionados. Se encontró que los modelos más complejos SVH, ANC y PGB, son los que mejor describen la densidad del líquido saturado (alrededor de 7% de desviación promedio, pero estos modelos generan desviaciones mayores al 40% para las propiedades del vapor y al 20% para la entalpia de vaporización. Por otro lado, el modelo no- polar BLF generó las menores desviaciones para la presión de saturación y la densidad del vapor (6.8 y 21.5%, respectivamente. Este modelo, al igual que el modelo HCB, produce desviaciones aceptables para la densidad del líquido y la entalpia de vaporización (entre 10 y 12%. Los modelos no polares BLF y HCB, que no requieren el cálculo de las interacciones de largo alcance, se pueden considerar como los modelos moleculares que presentan un balance satisfactorio entre desviaciones en los resultados y complejidad de cálculo.

Prediction of vapor pressure and heats of vaporization of edible oil/fat compounds by group contribution

DEFF Research Database (Denmark)

Ceriani, Roberta; Gani, Rafiqul; Liu, Y.A.

2013-01-01

In the present work, a group contribution method is proposed for the estimation of vapor pressures and heats of vaporization of organic liquids found in edible fat/oil and biofuel industries as a function of temperature. The regression of group contribution parameters was based on an extensive...

Dynamic performance analysis of permanent magnet contactor with a flux-weakening control strategy

Science.gov (United States)

Wang, Xianbing; Lin, Heyun; Fang, Shuhua; Jin, Ping; Wang, Junhua; Ho, S. L.

2011-04-01

A new flux-weakening control strategy for permanent magnet contactors is proposed. By matching the dynamic attraction force and the antiforce, the terminal velocity and collision energy of the movable iron in the closing process are significantly reduced. The movable iron displacement is estimated by detecting the closing voltage and current with the proposed control. A dynamic mathematical model is also established under four kinds of excitation scenarios. The attraction force and flux linkage are predicted by finite element method and the dynamics of the closing process is simulated using the 4th-order Runge-Kutta algorithm. Experiments are carried out on a 250A prototype with an intelligent control unit to verify the proposed control strategy.

Released air during vapor and air cavitation

Energy Technology Data Exchange (ETDEWEB)

Jablonská, Jana, E-mail: jana.jablonska@vsb.cz; Kozubková, Milada, E-mail: milada.kozubkova@vsb.cz [VŠB-Technical University of Ostrava, Faculty of Mechanical Engineering, Department of Hydromechanics and Hydraulic Equipment, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)

2016-06-30

Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ε model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

Study of near-critical states of liquid-vapor phase transition of magnesium

International Nuclear Information System (INIS)

Emelyanov, A N; Shakhray, D V; Golyshev, A A

2015-01-01

Study of thermodynamic parameters of magnesium in the near-critical point region of the liquid-vapor phase transition and in the region of metal-nonmetal transition was carried out. Measurements of the electrical resistance of magnesium after shock compression and expansion into gas (helium) environment in the process of isobaric heating was carried out. Heating of the magnesium surface by heat transfer with hot helium was performed. The registered electrical resistance of expanded magnesium was about 10 4 -10 5 times lower than the electrical resistance of the magnesium under normal condition at the density less than the density of the critical point. Thus, metal-nonmetal transition was found in magnesium. (paper)

Quantitative analysis of urine vapor and breath by gas-liquid partition chromatography.

Science.gov (United States)

Pauling, L; Robinson, A B; Teranishi, R; Cary, P

1971-10-01

When a human being is placed for several days on a completely defined diet, consisting almost entirely of small molecules that are absorbed from the stomach into the blood, intestinal flora disappear because of lack of nutrition. By this technique, the composition of body fluids can be made constant (standard deviation about 10%) after a few days, permitting significant quantitative analyses to be performed. A method of temperature-programmed gas-liquid partition chromatography has been developed for this purpose. It permits the quantitative determination of about 250 substances in a sample of breath, and of about 280 substances in a sample of urine vapor. The technique should be useful in the application of the principles of orthomolecular medicine.

Exchange between the stagnant and flowing zone in gas-flowing solids-fixed bed contactors

Directory of Open Access Journals (Sweden)

ALEKSANDAR P. DUDUKOVIC

2005-02-01

Full Text Available In countercurrent gas – flowing solids – fixed bed contactors, a fraction of the flowing solids is in motion (dynamic holdup, while the other fraction is resting on the fixed bed elements. In this study it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles. Combining a mathematical model with tracer experiments, the rate of exchange was determined and it was shown that only a small part (ca. 20 % of the stagnant region should be considered as a dead one.

Synthesis and refining of sunflower biodiesel in a cascade of continuous centrifugal contactor separators

NARCIS (Netherlands)

Bin Abu Ghazali, Yusuf; van Ulden, Wouter; van de Bovenkamp, Hendrik; Teddy, T; Picchioni, Francesco; Manurung, Robert; Heeres, Hero J.

The synthesis of fatty acid methyl esters (FAME) from sunflower oil and methanol was studied in a continuous centrifugal contactor separator (CCCS) using sodium methoxide as the catalyst. The effect of relevant process variables like oil and methanol flow rate, rotational speed and catalyst

Density Relaxation of Liquid-Vapor Critical Fluids Examined in Earth's Gravity

Science.gov (United States)

Wilkinson, R. Allen

2000-01-01

This work shows quantitatively the pronounced differences between the density equilibration of very compressible dense fluids in Earth's gravity and those in microgravity. The work was performed onsite at the NASA Glenn Research Center at Lewis Field and is complete. Full details are given in references 1 and 2. Liquid-vapor critical fluids (e.g., water) at their critical temperature and pressure, are very compressible. They collapse under their own weight in Earth's gravity, allowing only a thin meniscus-like layer with the critical pressure to survive. This critical layer, however, greatly slows down the equilibration process of the entire sample. A complicating feature is the buoyancy-driven slow flows of layers of heavier and lighter fluid. This work highlights the incomplete understanding of the hydrodynamics involved in these fluids.

Liquids and liquid mixtures

CERN Document Server

Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

2013-01-01

Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

The use of stochastic method for the calculation of liquid-vapor multicomponent equilibrium and the contribution of groups theory for the evaluation of fugacity coefficient; Uso de um metodo estocastico para calculo do equilibrio liquido-vapor de sistemas multicomponentes e avaliacao de uma abordagem por contribuicao de grupos para o calculo do coeficiente de fugacidade

Energy Technology Data Exchange (ETDEWEB)

Cavalcanti, Rafaelly L.; Oliveira, Jackson A. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia Quimica; Rojas, Leopoldo O.A. [Centro de Tecnologias do Gas (CTGAS), Natal, RN (Brazil)

2008-07-01

This work has the main objective of evaluating the mathematical model developed by Jaubert e Mutelet (2004) in terms of the prediction capacity for the calculation of the vapor-liquid equilibrium (VLE). This model is based on Peng-Robinson equation of state (EOS) and it considers the binary interaction parameters (Kij(T)) estimated by a contribution group method and dependent of the temperature. The model proposed by Jaubert e Mutelet (2004), named PPR78 (Predictive Peng-Robinson), was implemented in this work by using the Fortran language. An optimization approach based on the stochastic algorithm of Particle Swarm Optimization (PSO) was used in order to calculate the vapor-liquid equilibrium. Simulations were accomplished for several binary systems and the results were concordant with some experimental data of the investigated systems. However, for some systems different from those presented by Jaubert and Mutelet (2004), the model presented low prediction capacity. In spite of the great demand of computational performance, the algorithm PSO demonstrated robustness during the calculation of VLE and it assured convergence in most of the cases. (author)

Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure%Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure

Institute of Scientific and Technical Information of China (English)

王琳; 曹丰璞; 刘珊珊; 杨浩

2011-01-01

High-pressure vapor-liquid phase equilibrium data for carbon dioxide＋ isopentanol were measured at tempera- tures of 313.2, 323.1, 333.5 and 343.4 K in the pressure range of 4.64 to 12.71 MPa in a variable-volume high-pressure visual cell. The experimental data were well correlated with Peng-Robinson equation of state （PR-EOS） together with van der Waals-2 two-parameter mixing rule, and the binary interaction parameters were obtained. Henry coefficients and partial molar volumes of CO2 at infinite dilution were estimated based on Krichevsky-Kasarnovsky equation, and Henry coefficients increase with increasing temperature, however, partial molar volumes of CO2 at infinite dilution are negative and the magnitudes decrease with temperature.

Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C{sub 1}-C{sub 4}) and dimethyl carbonate

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Hiroyuki, E-mail: matsuda@chem.cst.nihon-u.ac.jp [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Fukano, Makoto; Kikkawa, Shinichiro [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Constantinescu, Dana [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany); Kurihara, Kiyofumi; Tochigi, Katsumi; Ochi, Kenji [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Gmehling, Juergen [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

2012-01-15

Highlights: > The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. > VLE data for ternary and binary mixtures containing alcohol and DMC were measured. > Several activity coefficient models were used for data reduction or prediction. > Valley line, i.e., distillation boundary, was observed for the ternary mixture. > Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {l_brace}methanol + propan-1-ol + dimethyl carbonate (DMC){r_brace}, and four binary mixtures, namely an {l_brace}alcohol (C{sub 3} or C{sub 4}) + DMC{r_brace}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

Molecular Models for DSMC Simulations of Metal Vapor Deposition

OpenAIRE

Venkattraman, A; Alexeenko, Alina A

2010-01-01

The direct simulation Monte Carlo (DSMC) method is applied here to model the electron‐beam (e‐beam) physical vapor deposition of copper thin films. A suitable molecular model for copper‐copper interactions have been determined based on comparisons with experiments for a 2D slit source. The model for atomic copper vapor is then used in axi‐symmetric DSMC simulations for analysis of a typical e‐beam metal deposition system with a cup crucible. The dimensional and non‐dimensional mass fluxes obt...

Method of estimating changes in vapor concentrations continuously generated from two-component organic solvents.

Science.gov (United States)

Hori, Hajime; Ishidao, Toru; Ishimatsu, Sumiyo

2010-12-01

We measured vapor concentrations continuously evaporated from two-component organic solvents in a reservoir and proposed a method to estimate and predict the evaporation rate or generated vapor concentrations. Two kinds of organic solvents were put into a small reservoir made of glass (3 cm in diameter and 3 cm high) that was installed in a cylindrical glass vessel (10 cm in diameter and 15 cm high). Air was introduced into the glass vessel at a flow rate of 150 ml/min, and the generated vapor concentrations were intermittently monitored for up to 5 hours with a gas chromatograph equipped with a flame ionization detector. The solvent systems tested in this study were the methanoltoluene system and the ethyl acetate-toluene system. The vapor concentrations of the more volatile component, that is, methanol in the methanol-toluene system and ethyl acetate in the ethyl acetate-toluene system, were high at first, and then decreased with time. On the other hand, the concentrations of the less volatile component were low at first, and then increased with time. A model for estimating multicomponent organic vapor concentrations was developed, based on a theory of vapor-liquid equilibria and a theory of the mass transfer rate, and estimated values were compared with experimental ones. The estimated vapor concentrations were in relatively good agreement with the experimental ones. The results suggest that changes in concentrations of two-component organic vapors continuously evaporating from a liquid reservoir can be estimated by the proposed model.

Vapor-liquid equilibrium of the Mg(NO3)2-HNO3-H2O system

International Nuclear Information System (INIS)

Thompson, B.E.; Derby, J.J.; Stalzer, E.H.

1983-06-01

The vapor-liquid equilibrium of the Mg(NO 3 ) 2 -HNO 3 -H 2 O system in concentrations of 0 to 70 wt % Mg(NO 3 ) 2 and 0 to 75 wt % HNO 3 at atmospheric pressure was correlated by two approaches. One was based on a dissociation equilibrium expression in which the activities of the reacting species (HNO 3 , NO 3 - , and H + ) were approximated with mole fractions. The activity coefficients of the undissociated HNO 3 and H 2 O were correlated as functions of the concentrations of magnesium nitrate and nitric acid by second-order polynomials. The average absolute difference between predicted and experimental values was 8% for the mole fraction of acid in the vapor and 8 0 K for the bubble-point temperature. The second approach was to correlate the mean ionic rational activity coefficient of water with a form of the excess Gibbs energy composed of two terms. One term, a function of the ionic strength, accounts for the coulombic (ionic) interactions; the other term accounts for the non-coulombic (molecular) interactions. The average absolute difference between predicted and experimental values was 9% for the mole fraction of acid in the vapor, and 10 0 K for the bubble-point temperature

Densities of liquids and vapors in boiling NaCl-H2O solutions: a PVTx summary from 300° to 500°C

Science.gov (United States)

Bischoff, James L.

1991-01-01

Experimental data for densities of liquids and vapors on the two-phase surface of the system NaCl-H2O were compiled and evaluated to provide a complete summary between 300° and 500°C. The results are added to a previously published PTx summary compiled in the same manner to provide a PVTx summary of the present state of knowledge. Results are in table form of use to the understanding of two-phase behaviour in boiling hydrothermal systems and to theoretical modeling of this important system. 

Dual vapor extraction on acidic sludge tar at a former refinery

International Nuclear Information System (INIS)

Lear, P.R.; Beall, P.; Townsend, S.

1996-01-01

OHM Remediation Services Corp conducted a pilot-scale demonstration for a novel application of dual vapor extraction technology for the pretreatment of the acid tar sludge material. The acid tar sludge comprised of approximately 60% asphaltene hydrocarbon material, 20% clay, and up to 20% sulfuric acid (H 2 SO 4 ). The liquid layer in the bottom of the pits has a low pH ( 2 ) gas which is released with the sludge material is excavated or handled. The objective of the dual vapor extraction was to remove the SO 2 vapors and liquid layer containing sulfuric acid prior to any further treatment. The dual vapor extraction would reduce the amount of alkaline reagent required for neutralization while eliminating the health and safety concerns. Overall, the DVE pilot demonstration successfully showed that both liquids and vapors could be removed from the acid tar sludge material. The liquid present in the lower portions of the pits will have pH values of 1.0 or less and acidities on the order of 5% H 2 SO 4 . The liquid removed from the acid tar sludge material by a DVE system will have slightly higher pH (∼1.5) and lower alkalinities (∼3% H 2 SO 4 ). The SO 2 concentration in the vapors removed by the DVE system will be variable with initial levels approaching 1,200 ppmv SO 2 . The SO 2 concentration in the vapor phase should decrease with time. A caustic scrubber solution will remove any SO 2 from the vapor phase. After DVE treatment, the acid tar sludge material would have a slightly increased pH and a decreased SO 2 concentration

Reply to "On Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K- A high temperature mass spectrometric study"

Science.gov (United States)

Jain, Uttam; Mukherjee, Abhishek

2018-03-01

This communication is in response to a letter to editor commenting on the authors' earlier paper "Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K - A high temperature mass spectrometric study".

Feasibility of using of the second gradient theory for the direct numerical simulation of liquid-vapor flows with phase-change; Etude des potentialites de la theorie du second gradient pour la simulation numerique directe des ecoulements liquide-vapeur avec changement de phase

Energy Technology Data Exchange (ETDEWEB)

Jamet, D. [CEA Grenoble, 38 (France). Dept. de Thermohydraulique et de Physique]|[Ecole Centrale de Paris, 75 (France)

1998-12-31

One on the main difficulties encountered in the direct numerical simulation of two-phase flows in general and of liquid-vapor flows with phase-change in particular, is the interface tracking. The idea developed in this work consists in modeling a liquid-vapor interface as a volumetric zone across which physical properties vary continuously instead of a discontinuous surface. The second gradient theory allows to establish the evolution equations of the fluid in the whole system: bulk phases and interfaces. That means that the resolution of a unique system of partial differential equations is necessary to determine the whole two-phase flow, the interfaces and their evolution in time being a part of the solution of this unique system. We show in this work that it is possible to artificially enlarge an interface without changing its surface tension and the latent heat of vaporization. That means than it is possible to track all the interfaces of a liquid-vapor two-phase flow with phase-change on a mesh the size of which is imposed by the smallest Kolmogorov scale of the bulk phases for example. The artificial enlargement of an interfacial zone is obtained by modifying the thermodynamic behavior of the fluid within the binodal. We show that this modification does not change the dynamics of an interface. However, although the thickness of an interface and its surface tension vary with the mass and heat fluxes that go though it, the thermodynamic modification necessary to the artificial enlargement of an interface drastically increases these variations. Consequently, the artificial enlargement of an interface must be made carefully to avoid a too much important variation of its surface tension during dynamic situations. (author) 60 refs.

The plasma properties and electron emission characteristics of near-zero differential resistance of hollow cathode-based plasma contactors with a discharge chamber

Energy Technology Data Exchange (ETDEWEB)

Xie, Kan, E-mail: xiekan@bit.edu.cn [School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China); Farnell, Casey C.; Williams, John D. [Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80524 (United States)

2014-08-15

The formation of electron emission-bias voltage (I-V) characteristics of near-zero differential resistance in the cathodic plasma contactor for bare electrodynamic tether applications, based on a hollow cathode embedded in a ring-cusp ionization stage, is studied. The existence of such an I-V regime is important to achieve low impedance performance without being affected by the space plasma properties for a cathodic plasma contactor. Experimental data on the plasma structure and properties downstream from the ionization stage are presented as functions of the xenon flow rate and the electron emission current. The electrons were emitted from the cathode to the cylindrical vacuum chamber wall (r = 0.9 m) under ≈10{sup −5 }Torr of vacuum pressure. The ring-cusp configuration selected for the plasma contactor created a 125-Gauss axial field near the cathode orifice, along with a large-volume 50-Gauss magnitude pocket in the stage. A baseline ion energy cost of ≈300 eV/ion was measured in the ionization stage when no electrons were emitted to the vacuum chamber wall. In addition, the anode fall growth limited the maximum propellant unitization to below ≈75% in the discharge loss curves for this ion stage. Detailed measurements on the plasma properties were carried out for the no-electron emission and 3 A emission conditions. The experimental data are compared with 1-D models, and the effectiveness of the model is discussed. The four key issues that played important roles in the process of building the near-zero different resistance I-V regime are: a significant amount of ionization by the emission electrons, a decrease in the number of reflected electrons in the plume, the electron-temperature increment, and low initial ion energy at the source outlet.

Microscale interfacial behavior at vapor film collapse on high-temperature particle surface

International Nuclear Information System (INIS)

Abe, Yutaka; Tochio, Daisuke

2009-01-01

It has been pointed out that vapor film on a premixed high-temperature droplet surface should be collapsed to trigger vapor explosion. Thus, it is important to clarify the micromechanism of vapor film collapse behavior for the occurrence of vapor explosion. In the present study, microscale vapor-liquid interface behavior upon vapor film collapse caused by an external pressure pulse is experimentally observed and qualitatively analyzed. In the analytical investigation, interfacial temperature and interface movement were estimated with heat conduction analysis and visual data processing technique. Results show that condensation can possibly occur at the vapor-liquid interface when the pressure pulse arrived. That is, this result indicates that the vapor film collapse behavior is dominated not by fluid motion but by phase change. (author)

Vapor Pressures of Several Commercially Used Alkanolamines

NARCIS (Netherlands)

Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

Biodiesel synthesis from Jatropha curcas L. oil and ethanol in a continuous centrifugal contactor separator

NARCIS (Netherlands)

Abduh, Muhammad Yusuf; van Ulden, Wouter; Kalpoe, Vijay; van de Bovenkamp, Hendrik H.; Manurung, Robert; Heeres, Hero J.

The synthesis of fatty acid ethyl esters (FAEE) from Jatropha curcas L. oil was studied in a batch reactor and a continuous centrifugal contactor separator (CCCS) using sodium ethoxide as the catalyst. The effect of relevant process variables like rotational speed, temperature, catalyst

Determination of the enthalpy of vaporization and prediction of surface tension for ionic liquid 1-alkyl-3-methylimidazolium propionate [C(n)mim][Pro](n = 4, 5, 6).

Science.gov (United States)

Tong, Jing; Yang, Hong-Xu; Liu, Ru-Jing; Li, Chi; Xia, Li-Xin; Yang, Jia-Zhen

2014-11-13

With the use of isothermogravimetrical analysis, the enthalpies of vaporization, Δ(g)lH(o)m(T(av)), at the average temperature, T(av) = 445.65 K, for the ionic liquids (ILs) 1-alkyl-3-methylimidazolium propionate [C(n)mim][Pro](n = 4, 5, 6) were determined. Using Verevkin's method, the difference of heat capacities between the vapor phase and the liquid phase, Δ(g)lC(p)(o)m, for [C(n)mim][Pro](n = 2, 3, 4, 5, 6), were calculated based on the statistical thermodynamics. Therefore, with the use of Δ(g)lC(p)(o)m, the values of Δ(g)lH(o)m(T(av)) were transformed into Δ(g)lH(o)m(298), 126.8, 130.3, and 136.5 for [C(n)mim][Pro](n = 4, 5, 6), respectively. In terms of the new scale of polarity for ILs, the order of the polarity of [C(n)mim][Pro](n = 2, 3, 4, 5, 6) was predicted, that is, the polarity decreases with increasing methylene. A new model of the relationship between the surface tension and the enthalpy of vaporization for aprotic ILs was put forward and used to predict the surface tension for [C(n)mim][Pro](n = 2, 3, 4, 5, 6) and others. The predicted surface tension for the ILs is in good agreement with the experimental one.

Viscosities of cesium vapor to 1,620 K and of liquid gallium to 1,800 K

International Nuclear Information System (INIS)

Tippelskirch, H. v.

1976-01-01

The viscosity of cesium at 1,620 K and 40 bar has been determined to 41 x 10 -6 (Pa x s) by the oscillating cup method. The saturated vapor density at 1,580 K could be derived from the viscosity measurements. The viscosity of liquid gallium has been determined from 370 K to 1,800 K. The experimental results have been compared with calculations based on the Enskog hard-sphere transport theory for dense fluids. (orig.) [de

Nucleation and growth of microdroplets of ionic liquids deposited by physical vapor method onto different surfaces

Science.gov (United States)

Costa, José C. S.; Coelho, Ana F. S. M. G.; Mendes, Adélio; Santos, Luís M. N. B. F.

2018-01-01

Nanoscience and technology has generated an important area of research in the field of properties and functionality of ionic liquids (ILs) based materials and their thin films. This work explores the deposition process of ILs droplets as precursors for the fabrication of thin films, by means of physical vapor deposition (PVD). It was found that the deposition (by PVD on glass, indium tin oxide, graphene/nickel and gold-coated quartz crystal surfaces) of imidazolium [C4mim][NTf2] and pyrrolidinium [C4C1Pyrr][NTf2] based ILs generates micro/nanodroplets with a shape, size distribution and surface coverage that could be controlled by the evaporation flow rate and deposition time. No indication of the formation of a wetting-layer prior to the island growth was found. Based on the time-dependent morphological analysis of the micro/nanodroplets, a simple model for the description of the nucleation process and growth of ILs droplets is presented. The proposed model is based on three main steps: minimum free area to promote nucleation; first order coalescence; second order coalescence.

X-ray studies of the liquid/vapor interface: Water and polymer and fatty acid monolayers on water

International Nuclear Information System (INIS)

Schlossman, M.L.; Schwartz, D.K.; Kawamoto, E.H.; Kellogg, G.J.; Pershan, P.S.; Ocko, B.M.; Kim, M.W.; Chung, T.C.

1989-01-01

X-ray specular reflectivity is used to study the liquid-vapor interface of pure water and of fatty acid and polymer monolayers at that interface. For the pure water surface the reflectivity was measured for three different spectrometer resolutions and simultaneous fits with only one free parameter to all of the data are in excellent agreement with the prediction of capillary wave theory for the RMS surface roughness. Diffuse scattering away from the specular condition, at wavevectors corresponding to those of the capillary waves, yields intensities and line shapes in agreement with theory with no significant adjustable parameters. Reflectivity from separate monolayers of co-poly 1, 2-butadiene/butyl alcohol (50% random substitution) and lignoceric acid (CH 3 (CH 2 ) 22 COOH) at the water/vapor interface are interpreted to obtain profiles of the average electron density ρ(z) as a function of distance z along the surface normal. For the polymer monolayer we find the following: (1) a local maximum in the electron density approximately 10% larger than that of the bulk polymer and (2) the RMS roughness of the vapor/polymer interface agrees with capillary wave theory predictions for the lower surface pressures. For the highest surface pressure the RMS roughness exceeds the value predicted by the capillary wave model. Measurements of reflectivity from a lignoceric acid monolayer, as a function of surface pressure throughout an isotherm (near room temperature), reveal the following behavior: (1) the overall thickness of the monolayer increases with increasing pressure and (2) the head groups occupy a progressively larger region along the surface normal as the pressure increases, indicating that they rearrange normal to the interface. 15 refs., 5 figs., 2 tabs

Vapor-liquid critical surface of ternary difluoromethane + pentafluoroethane + 1,1,1,2-tetrafluoroethane (R-32/125/134a) mixtures

Energy Technology Data Exchange (ETDEWEB)

Higashi, Y.

1999-09-01

The plane of vapor-liquid criticality for ternary refrigerant mixtures of difluoromethane (R-32) + pentafluoroethane (R-125) + 1,1,1,2-tetrafluoroethane (R-134a) was determined from data on the vapor-liquid coexistence curve near the mixture critical points. The composition (mass percentage) of the mixtures studied were 23% R-32 + 25% R-125 + 52% R-134a (R-407C). 25% R-32 + 15% R-125 + 60% R-134a (R-407E), and 20% R-32 + 40% R-125 + 40% R-134a (R-407A). The critical temperature of each mixture was determined by observation of the disappearance of the meniscus. The critical density of each mixture was determined on the basis of meniscus disappearance level and the intensity of the critical opalescence. The uncertainties of the temperature, density, and composition measurements are estimated as {+-}10mK, {+-}5kg{center_dot}m{sup {minus}3}, and {+-}0.05%, respectively. In addition, predictive methods for the critical parameters of R-32/125/134a mixtures are discussed.

Clean-in-Place and Reliability Testing of a Commercial 12.5-cm Annular Centrifugal Contactor at the INL

International Nuclear Information System (INIS)

N. R. Mann; T. G. Garn; D. H. Meikrantz; J. D. Law; T. A. Todd

2007-01-01

The renewed interest in advancing nuclear energy has spawned the research of advanced technologies for recycling nuclear fuel. A significant portion of the advanced fuel cycle includes the recovery of selected actinides by solvent extraction methods utilizing centrifugal contactors. Although the use of centrifugal contactors for solvent extraction is widely known, their operation is not without challenges. Solutions generated from spent fuel dissolution contain unknown quantities of undissolved solids. A majority of these solids will be removed via various methods of filtration. However, smaller particles are expected to carry through to downstream solvent extraction processes and equipment. In addition, solids/precipitates brought about by mechanical or chemical upsets are another potential area of concern. During processing, particulate captured in the rotor assembly by high centrifugal forces eventually forms a cake-like structure on the inner wall introducing balance problems and negatively affecting phase separations. One of the features recently developed for larger engineering scale Annular Centrifugal Contactors (ACCs) is the Clean-In-Place (CIP) capability. Engineered spray nozzles were installed into the hollow central rotor shaft in all four quadrants of the rotor assembly. This arrangement allows for a very convenient and effective method of solids removal from within the rotor assembly

Clean-in-Place and Reliability Testing of a Commercial 12.5 cm Annular Centrifugal Contactor at the INL

International Nuclear Information System (INIS)

N. R. Mann; T. G. Garn; D. H. Meikrantz; J. D. Law; T. A. Todd

2007-01-01

The renewed interest in advancing nuclear energy has spawned the research of advanced technologies for recycling nuclear fuel. A significant portion of the advanced fuel cycle includes the recovery of selected actinides by solvent extraction methods utilizing centrifugal contactors. Although the use of centrifugal contactors for solvent extraction is widely known, their operation is not without challenges. Solutions generated from spent fuel dissolution contain unknown quantities of undissolved solids. A majority of these solids will be removed via various methods of filtration. However, smaller particles are expected to carry through to downstream solvent extraction processes and equipment. In addition, solids/precipitates brought about by mechanical or chemical upsets are another potential area of concern. During processing, particulate captured in the rotor assembly by high centrifugal forces eventually forms a cake-like structure on the inner wall introducing balance problems and negatively affecting phase separations. One of the features recently developed for larger engineering scale Annular Centrifugal Contactors (ACCs) is the Clean-In-Place (CIP) capability. Engineered spray nozzles were installed into the hollow central rotor shaft in all four quadrants of the rotor assembly. This arrangement allows for a very convenient and effective method of solids removal from within the rotor assembly

Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

Energy Technology Data Exchange (ETDEWEB)

Ratcliff, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McCormick, Robert L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Burke, Stephen [Colorado State University; Rhoads, Robert [University of Colorado; Windom, Bret [Colorado State University

2018-04-03

A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol's high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recently through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion. To better understand the role of the azeotrope interactions on the vapor/liquid composition evolution of the fuel, distillations were performed using the Advanced Distillation Curve apparatus on carefully selected samples consisting of gasoline blended with ethanol and heavy aromatic and oxygenated compounds with varying vapor pressures, including cumene, p-cymene, 4-tertbutyl toluene, anisole, and 4-methyl anisole. Samples collected during the distillation indicate an enrichment of the heavy aromatic or oxygenated additive with an increase in initial ethanol concentration from E0 to E30. A recently developed distillation and droplet evaporation model is used to explore the influence of dilution effects versus azeotrope interactions on the aromatic species enrichment. The results suggest that HOV-cooling effects as well as aromatic species enrichment behaviors should be considered in future development of predictive indices to forecast the PM potential of fuels containing oxygenated compounds with comparatively high HOV.

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

Energy Technology Data Exchange (ETDEWEB)

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

The annual cycle of stratospheric water vapor in a general circulation model

Science.gov (United States)

Mote, Philip W.

1995-01-01

The application of general circulation models (GCM's) to stratospheric chemistry and transport both permits and requires a thorough investigation of stratospheric water vapor. The National Center for Atmospheric Research has redesigned its GCM, the Community Climate Model (CCM2), to enable studies of the chemistry and transport of tracers including water vapor; the importance of water vapor to the climate and chemistry of the stratosphere requires that it be better understood in the atmosphere and well represented in the model. In this study, methane is carried as a tracer and converted to water; this simple chemistry provides an adequate representation of the upper stratospheric water vapor source. The cold temperature bias in the winter polar stratosphere, which the CCM2 shares with other GCM's, produces excessive dehydration in the southern hemisphere, but this dry bias can be ameliorated by setting a minimum vapor pressure. The CCM2's water vapor distribution and seasonality compare favorably with observations in many respects, though seasonal variations including the upper stratospheric semiannual oscillation are generally too small. Southern polar dehydration affects midlatitude water vapor mixing ratios by a few tenths of a part per million, mostly after the demise of the vortex. The annual cycle of water vapor in the tropical and northern midlatitude lower stratosphere is dominated by drying at the tropical tropopause. Water vapor has a longer adjustment time than methane and had not reached equilibrium at the end of the 9 years simulated here.

Trial of Neem Oil (Azadirachta Indica) as Basic Compound of Electric Liquid Vaporizer Against Aedes Aegypti Mortality

OpenAIRE

Diptyanusa, Ajib; Satoto, Tri Baskoro Tunggul; Hadianto, Tridjoko

2017-01-01

Dengue Hemorrhagic Fever (DHF), commonly caused by Aedes aegypti mosquito bites, has been one of the worlds major concern for progressively increasing incidence. To prevent further increase in DHF incidence, an effective yet safe vector control method is needed. One of the most common method of vector control in Indonesia is using electric liquid vaporizer. Basic compounds which are less toxic to humans and less resistance-producing to mosquitoes are preferred, without neglecting its ability ...

Fragmentation of suddenly heated liquids in ICF reactors. Revision 1

International Nuclear Information System (INIS)

Blink, J.A.; Hoover, W.G.

1985-01-01

Fragmentation of free liquids in Inertial Confinement Fusion reactors could determine the upper bound on reactor pulse rate because increased surface area will enhance the cooling and condensation of coolant ablated by the fusion x rays. Relaxation from the suddenly (neutron) heated state will move a liquid into the negative pressure region under the liquid-vapor P-V dome. The resulting expansion in a diverging geometry will hydrodynamically force the liquid to fragment, with vapor then forming from the new surfaces to fill the cavities. An energy minimization model is used to determine the fragment size that produces the least amount of non-fragment-center-of-mass energy; i.e., the sum of the surface and dilational kinetic energies. This model predicts fragmentation dependence on original system size and amount of isochoric heating as well as liquid density, Grueneisen parameter, surface tension, and sound speed. A two dimensional molecular dynamics code was developed to test the model at a microscopic scale for the Lennard-Jones fluid with its two adjustable constants chosen to represent lithium

Layered interfaces between immiscible liquids studied by density-functional theory and molecular-dynamics simulations.

Science.gov (United States)

Geysermans, P; Elyeznasni, N; Russier, V

2005-11-22

We present a study of the structure in the interface between two immiscible liquids by density-functional theory and molecular-dynamics calculations. The liquids are modeled by Lennard-Jones potentials, which achieve immiscibility by suppressing the attractive interaction between unlike particles. The density profiles of the liquids display oscillations only in a limited part of the simple liquid-phase diagram (rho,T). When approaching the liquid-vapor coexistence, a significant depletion appears while the layering behavior of the density profile vanishes. By analogy with the liquid-vapor interface and the analysis of the adsorption this behavior is suggested to be strongly related to the drying transition.

Vapor-liquid equilibria of a minute amount of furfural in water-methanol-ethanol system; Mizu-methanol-ethanol keichu no biryo no furfural no kieki heiko

Energy Technology Data Exchange (ETDEWEB)

Ikari, A.; Hatate, Y.; Uemura, Y. [Kagoshima University, Kagoshima (Japan). Faculty of Engineering

1997-01-10

Vapor-liquid equilibria of a water-methanol-ethanol system containing a minute amount of furfural were measured at atmospheric pressure by use of an Othmer-type still. The experimental results are represented by four triangular diagrams against the liquid compositions of the major components (water, methanol and ethanol), in which three diagrams show the vapor composition of the major components, respectively, and one diagram shows the equilibrium ratio of the trace component (furfural). The curved surface of the equilibrium ratio of the trace component exhibits a gentle downward slope in most areas, but shows a half-saddle face in the neighborhood of the water-ethanol side. 4 refs., 10 figs., 3 tabs.

Modeling leaks from liquid hydrogen storage systems.

Energy Technology Data Exchange (ETDEWEB)

Winters, William Stanley, Jr.

2009-01-01

This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

Potassium permanganate for mercury vapor environmental control

Science.gov (United States)

Kuivinen, D. E.

1972-01-01

Potassium permanganate (KMnO4) was evaluated for application in removing mercury vapor from exhaust air systems. The KMnO4 may be used in water solution with a liquid spray scrubber system or as a solid adsorber bed material when impregnated onto a zeolite. Air samples contaminated with as much as 112 mg/cu m of mercury were scrubbed to 0.06mg/cum with the KMnO4-impregnated zeolite (molecular sieve material). The water spray solution of permanganate was also found to be as effective as the impregnated zeolite. The KMnO4-impregnated zeolite was applied as a solid adsorber material to (1) a hardware decontamination system, (2) a model incinerator, and (3) a high vacuum chamber for ion engine testing with mercury as the propellant. A liquid scrubber system was also applied in an incinerator system. Based on the results of these experiments, it is concluded that the use of KMnO4 can be an effective method for controlling noxious mercury vapor.

Kinetics of small particle activation in supersaturated vapors

Energy Technology Data Exchange (ETDEWEB)

McGraw, R.; Wang, J.

2010-08-29

We examine the nucleated (with barrier) activation of perfectly wetting (zero contact angle) particles ranging from bulk size down to one nanometer. Thermodynamic properties of the particles, coated with liquid layers of varying thickness and surrounded by vapor, are analyzed. Nano-size particles are predicted to activate at relative humidity below the Kelvin curve on crossing a nucleation barrier, located at a critical liquid layer thickness such that the total particle size (core + liquid layer) equals the Kelvin radius (Fig. 1). This barrier vanishes precisely as the critical layer thickness approaches the thin layer limit and the Kelvin radius equals the radius of the particle itself. These considerations are similar to those included in Fletcher's theory (Fletcher, 1958) however the present analysis differs in several important respects. Firstly, where Fletcher used the classical prefactor-exponent form for the nucleation rate, requiring separate estimation of the kinetic prefactor, we solve a diffusion-drift equation that is equivalent to including the full Becker-Doering (BD) multi-state kinetics of condensation/evaporation along the growth coordinate. We also determine the mean first passage time (MFPT) for barrier crossing (Wedekind et al., 2007), which is shown to provide a generalization of BD nucleation kinetics especially useful for barrier heights that are considerably lower than those typically encountered in homogeneous vapor-liquid nucleation, and make explicit comparisons between the MFPT and BD kinetic models. Barrier heights for heterogeneous nucleation are computed by a thermo-dynamic area construction introduced recently to model deliquescence and efflorescence of small particles (McGraw and Lewis, 2009). In addition to providing a graphical representation of the activation process that offers new insights, the area construction provides a molecular approach that avoids explicit use of the interfacial tension. Typical barrier profiles for

Determination of vapor-liquid equilibrium data and decontamination factors needed for the development of evaporator technology for use in volume reduction of radioactive waste streams

International Nuclear Information System (INIS)

Betts, S.E.

1993-01-01

A program is currently in progress at Argonne National Laboratory to evaluate and develop evaporator technology for concentrating radioactive waste streams. By concentrating radioactive waste streams, disposal costs can be significantly reduced. To effectively reduce the volume of waste, the evaporator must achieve high decontamination factors so that the distillate is sufficiently free of radioactive material. One technology that shows a great deal of potential for this application is being developed by LICON, Inc. In this program, Argonne plans to apply LICON's evaporator designs to the processing of radioactive solutions. Concepts that need to be incorporated into the design of the evaporator include, criticality safety, remote operation and maintenance, and materials of construction. To design an effective process for concentrating waste streams, both solubility and vapor-liquid equilibrium data are needed. The key issue, however, is the high decontamination factors that have been demonstrated by this equipment. Two major contributions were made to this project. First, a literature survey was completed to obtain available solubility and vapor-liquid equilibrium data. Some vapor-liquid data necessary for the project but not available in the literature was obtained experimentally. Second, the decontamination factor for the evaporator was determined using neutron activation analysis (NAA)

Rate theory of ion pairing at the water liquid-vapor interface: A case of sodium iodide

Science.gov (United States)

Dang, Liem X.; Schenter, Gregory K.

2018-06-01

Studies on ion pairing at interfaces have been intensified recently because of their importance in many chemical reactive phenomena, such as ion-ion interactions that are affected by interfaces and their influence on kinetic processes. In this study, we performed simulations to examine the thermodynamics and kinetics of small polarizable sodium iodide ions in the bulk and near the water liquid-vapor interface. Using classical transition state theory, we calculated the dissociation rates and corrected them with transmission coefficients obtained from the reactive flux formalism and Grote-Hynes theory. Our results show that in addition to affecting the free energy of ions in solution, the interfacial environments significantly influence the kinetics of ion pairing. The results on the relaxation time obtained using the reactive flux formalism and Grote-Hynes theory present an unequivocal picture that the interface suppresses ion dissociation. The effects of the use of molecular models on the ion interactions as well as the ion-pair configurations at the interface are also quantified and discussed.

Review on utilization of the pervaporation membrane for passive vapor feed direct methanol fuel cell

International Nuclear Information System (INIS)

Fauzi, N F I; Hasran, U A; Kamarudin, S K

2013-01-01

The Direct Methanol Fuel Cell (DMFC) is a promising portable power source for mobile electronic devices because of its advantages including easy fuel storage, high energy density, low temperature operation and compact structure. In DMFC, methanol is used as a fuel source where it can be fed in liquid or vapor phase. However, the vapor feed DMFC has an advantage over the liquid feed system as it has the potential to have a higher operating temperature to increase the reaction rates and power outputs, to enhance the mass transfers, to reduce methanol crossover, reliable for high methanol concentration and it can increase the fuel cell performance. Methanol vapor can be delivered to the anode by using a pervaporation membrane, heating the liquid methanol or another method that compatible. Therefore, this paper is a review on vapor feed DMFC as a better energy source than liquid feed DMFC, the pervaporation membrane used to vaporize methanol feed from the reservoir and its applications in vapor feed DMFC