J. A. Madariaga

University of the Basque Country

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Carlos Santamaría

Hospital Universitario de La Princesa

J. M. Savirón

University of the Basque Country

M. Mounir Bou‐Ali

Mondragon University

O. Ecenarro

University of the Basque Country

Jean-Michel Navarro

University of the Basque Country

J. A. Carrión

University of the Basque Country

David Alonso de Mezquıa

Mondragon University

J. J. Valencia

Universidad Publica de Navarra

J. Brun

Universidad de Zaragoza

Miren Larrañaga

Universidad de Oviedo

Cooperative Institutions

University of the Basque Country

Mondragon University

Universidad de Zaragoza

University of Mons

Universidad Publica de Navarra

Consejo Superior de Investigaciones Científicas

Centre National de la Recherche Scientifique

Universidad San Pablo CEU

Université de Pau et des Pays de l'Adour

Toronto Metropolitan University

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DIFFUSION PROCESSES IN CLUSIUS--DICKEL COLUMNS.

J. M. Savirón J. A. Madariaga Marta Quintanilla

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Citations (0)

Non-steady separation factor in a closed thermal diffusion column (isotope separation)

Journal of Physics A Mathematical and General (1975)

J. M. Savirón J. Brun J. A. Madariaga

From the Majumdar solution a simple analytical expression is obtained for the non-steady separation factor of a binary isotopic mixture in a thermal diffusion column closed at both ends. The result represents the exact solution very well, it is independent of the initial concentration and allows the value of the magnitude gamma =H2/ mu (Kc+Kd) to be easily obtained from experiment. The proposed formulation qualitatively interprets the principal characteristics of the experimental results of separation of 36Ar-40Ar at four temperatures. The influence of the non-active volumes present in the column is analysed and, by means of numerical calculus, an empirical expression is presented which gives a very good account of their influence on the determination of gamma .

Separation (statistics)

10.1088/0305-4470/8/9/018

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Citations (2)

Determination of the thermodiffusion coefficient in three binary organic liquid mixtures by the thermogravitational method (contribution of the Universidad del País Vasco, Bilbao, to the benchmark test)

The Philosophical Magazine A Journal of Theoretical Experimental and Applied Physics (2003)

M. Mounir Bou‐Ali J. J. Valencia J. A. Madariaga Carlos Santamaría O. Ecenarro

Within the framework of an international benchmark test, the thermodiffusion coefficients D T of the three binary systems formed with dodecane, isobutylbenzene and 1,2,3,4-tetrahydronaphthalene (with a mass fraction of 0.5 for each component at a temperature of 25C) have been measured. Convective coupling in cylindrical thermogravitational columns has been used to determine D T based on the Furry-Jones-Onsager theory. For each system, several columns with different gaps and heights were employed. Our results for these three coefficients are in good agreement with those obtained by other benchmark tests; the maximum deviation from the proposed benchmark values is 8.5%, which is not too bad owing to the difficulties of measuring a thermodiffusion coefficient.

Benchmark (surveying)

Mass fraction

Dodecane

10.1080/0141861031000113299

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Citations (35)

Non-Steady Separation of Multicomponent Isotopic Mixtures in Clusius-Dickel Columns

Journal of the Physical Society of Japan (1975)

J. M. Savirón David González J. Brun J. A. Madariaga

Analytical expressions for the non steady separation factor of an isotopic multicomponent mixture in a thermal diffusion column are given. The results, which are appropiate for column operation at total reflux and cover the real case in which small non active end volumes are present, show a simple exponential rising of the logarithm of the reduced separation factor independent of the initial mixture composition. This fact is confirmed by experimental transient data previously reported by Brun et al. and by new experimental work presented here. It is shown that the relative variations of the relaxation time with the hot wire temperature and with the operation pressure are just those predicted by the Furry, Jones and Onsager theory. It is concluded that two experimental operations: steady-separation vs pressure and non-steady separation vs time, and the use of FJO theory will allow us the qualitative prediction of the column operation in the usual temperature and pressure range in laboratory operation

Separation (statistics)

Transient (computer programming)

10.1143/jpsj.39.1417

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Citations (3)

Experimental Results on Non-Active End Volume Influence in the Transient Separation of Thermal Diffusion Columns

Journal of the Physical Society of Japan (1977)

J. M. Savirón David González M. D. Mendia J. Brun J. A. Madariaga

A hot wire thermal diffusion column with a variable non-active volume has been constructed, The experimental results for the relaxation time as a function of the non-active volume are compared with the theoretical predictions. The good agreement obtained suggests that-our transient formulation can confidently be used to determine the experimental values of the column coefficients. The relaxation time measurements do not permit to distinguish between the active and non-active parts of a column, and the remixing coefficients K c and K d can be experimentallv obtained without an explicit knowledge of the non-active volumes in the column.

Transient (computer programming)

10.1143/jpsj.42.935

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Citations (2)

Thermodiffusion Coefficient for Binary Liquid Hydrocarbon Mixtures

Journal of Non-Equilibrium Thermodynamics (2007)

Pablo Blanco M. Mounir Bou‐Ali J. K. Platten J. A. Madariaga Pedro Urteaga

In this work, the thermogravitational technique has been used to determine the thermodiffusion coefficient of 18 binary mixtures of normal alkanes formed with the n-octadecane as the densest component and mixed with normal alkanes from n-pentane to n-tridecane in two series of experimental tests (nine binary mixtures with mass fraction c = 0.5 and nine binary mixtures with molar fraction x = 0.5 in each component for each mixture). The measurement of the steady separation of these mixtures in the thermogravitational column, as well as their corresponding thermophysical properties, has been determined at the average temperature of 25°C.

Octadecane

Pentane

Component (thermodynamics)

Hydrocarbon mixtures

Mole fraction

Fraction (chemistry)

Mass fraction

Molar mass

10.1515/jnetdy.2007.023

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Citations (33)

Measurement of Thermodiffusion Coefficient in n-Alkane Binary Mixtures: Composition Dependence

The Journal of Physical Chemistry B (2010)

J. A. Madariaga Carlos Santamaría M. Mounir Bou‐Ali Pedro Urteaga David Alonso de Mezquıa

In this work, we have measured the thermodiffusion coefficient of different n-alkane binary mixtures at several concentrations using the thermogravitational technique. In particular, we have studied the n-dodecane/n-heptane system as a function of composition and other systems covering a large range of mass differences and concentration at 25 degrees C and 1 atm. The results show that for any concentration the thermodiffusion coefficient of n-alkane mixtures is proportional to the mass difference between the components and to the ratio of the thermal expansion coefficient and viscosity of the mixture. The obtained equation allows us to determine the infinite dilution values of the thermodiffusion coefficient. We compare these values with recent experimental results in dilute polymer solutions and analyze the Brenner theory of thermodiffusion. Finally, it is shown that the thermodiffusion coefficient depends linearly with the mass fraction, and it can be calculated from the viscosity and thermal expansion of the pure components.

Alkane

Dilution

Heptane

Dodecane

Mass fraction

10.1021/jp910823c

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Citations (34)

Mass effect on the Soret coefficient in n-alkane mixtures

The Journal of Chemical Physics (2014)

David Alonso de Mezquıa M. Mounir Bou‐Ali J. A. Madariaga Carlos Santamaría

We have determined the Soret coefficient of different equimolar and non equimolar n-alkane mixtures from measurements of the molecular diffusion and thermal diffusion coefficients. It is shown that equimolar mixtures behave as isotopic-like mixtures in which only the mass effect contributes to the Soret effect. In non equimolar mixtures, a small linear dependence with the molar fraction is observed. Finally, we have obtained a new correlation, which allows the determination of the Soret coefficient of n-alkane mixtures using the data of viscosity, the thermal expansion coefficient of the pure components, and the density of the equimolar mixture.

Alkane

Thermophoresis

Molar mass

Mole fraction

10.1063/1.4865936

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Citations (27)

Thermal Diffusion Factor for Carbon Tetrachloride-Cyclohexane and Benzene-n-Heptane Mixtures from Thermogravitational Column Separation

Separation Science and Technology (1985)

Jean-Michel Navarro J. A. Madariaga Carlos Santamaría J. M. Savirón J. A. Carrión

Abstract Measurements of the separation of liquid mixtures of n-heptane/benzene and carbon tetrachloride/cyclohexane in a thermogravitational column are reported. The results show that thermal diffusion columns of little mechanical precision can furnish suitable thermal diffusion factors when the diffusion coefficient, viscosity, density, and compressibility factor for the mixture are known.

Heptane

10.1080/01496398508060685

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Citations (5)

Thermogravitational separation and the thermal diffusion factor near critical points in binary liquid mixtures

Journal of Physics Condensed Matter (1993)

O. Ecenarro J. A. Madariaga Jean-Michel Navarro Carlos Santamaría J. A. Carrión

The thermogravitational separation for each of the binary liquid systems nitrobenzene+n-hexane and isobutyric acid+water as a function of composition was measured at temperatures above and near to their critical conditions. The first system, in which the component densities are very different, presents large separations near the critical composition. In contrast, in the second one, with similar densities of the pure components, no separation is observed. The extension to high Soret numbers of the authors' previously developed thermogravitational theory, which takes into account the effect of the buoyancy-driven convection induced by the density composition dependence allows them to obtain values of thermal diffusion factors of binary liquid mixtures in the vicinity of consolute points from separation measurements.

Nitrobenzene

Isobutyric acid

Component (thermodynamics)

Hexane

10.1088/0953-8984/5/15/002

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Citations (12)