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TAKUO SHIGETOMI, TOMOSHIGE NITTA, TAKASHI KATAYAMA
1982 Volume 15 Issue 4 Pages
249-254
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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An adsorption model combining localized and nonlocalized adsorptions is presented to interpret the adsorption isotherms of water and methanol in zeolitic sorbents of type A. The Langmoir equation is used for the localized adsorption of water and the van der-Waals-type equation is suggested for nonlocalized adsorption. For methanol adsorption the extended form of the Langmuir equation based upon the model in which one molecule occupies two adjacent sites, plays a significant role. Single-component adsorptions of water and methanol on Molecular Sieve 4A are represented fairly well by means of two adjustable parameters, an adsorption equilibrium constant and a physical interaction parameter. The theory can predict the selective adsorption of water from aqueous methanol solutions without any adjustable parameters.
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KUNIO KATAOKA, HITOSHI MATSUO, HIROYUKI SHUNDOH
1982 Volume 15 Issue 4 Pages
255-261
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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A generalized eddy transfer coefficient model has been experimentally obtained for axisymmetric, nonisothermal variable-density jets, the initial density ratio of which ranges from 0.66 to 5.1. The local variation in the dynamic eddy transfer coefficients for momentum and heat has been measured in the developed region: both transfer coefficients on the jet axis are proportional to the square root of the initial density ratio, but are almost independent of the axial distance from the nozzle exit; the transfer coefficients for momentum and a chemical species remain constant in the inner region whereas the transfer coefficient for heat decreases slightly with increasing radial distance; all the transfer coefficients decrease rapidly in the outer region owing to the intermittent entrainment of the quiescent ambient fluid. The present model can perdict local values of the transfer coefficients over the range of initial density ratio from 0.66 to 5.1 if the initial jet condition alone is specified at a nozzle exit.
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TATSUO KANKI, SATORU IUCHI, YOSHINORI MATSUI, YUJI YAMAMOTO
1982 Volume 15 Issue 4 Pages
261-267
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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A new, explicit equation for nononiforni pressure diffusion of a ternary gas mixture in a circular tube is obtained. The theory employed is based on the authors'' existing kinetic model of foursided local velocity distributions. The diffusion equation shows that transport of the individual components is expressed by a simple summation of two separated terms of diffusional and hydrodynamic flows. Validity of the equation is shown by comparison of the fluxes with those measured for a He-Ne-Ar mixture through a diffusion bridge. The diffusion equation gives a physical explanation for striking phenomena at low pressures, such as Hoogschagen''s nonequimolar counter-diffusion at a uniform pressure, diffusio-molecular pressure effect, velocity slip at the channel wall, and Knudsen''s minimum in volume flow.
The concept of "diffusional momentum slip" is newly proposed. Use of this concept is effective in deriving the solutions to transport of gases at low pressures directly from the continuum theory.
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HITOSHI KOSUGE, KOICHI ASANO
1982 Volume 15 Issue 4 Pages
268-273
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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Experimental study of vapor-phase sensible heat and mass fluxes in ternary distillation of the methanol-ethanol-water system was made with a wetted-wall column at total reflux conditions.
From heat and mass balances for the liquid film, a theoretical expression was derived for the interfacial velocity caused by mass fluxes. The interfacial velocity was shown to be a function of the sensible heat and diffusion fluxes.
Observed vapor-phase sensible heat fluxes showed good agreement with the theoretical values obtained by laminar flow theories. Observed vapor-phase diffusion fluxes obtained from mass flux measurements also showed good agreement with the theoretical values, but a poor correlation was obtained for vapor-phase mass fluxes. Observed interfacial velocities were compared with the calculated values.
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FUMIYUKI NAKASHIO, KAZUO KONDO, AKINORI MURAKAMI, YOSHIRO AKIYOSHI
1982 Volume 15 Issue 4 Pages
274-279
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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Measurements of the extraction equilibria of copper and zinc with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester dissolved in w-heptane or toluene diluent were carried out at 303 K.
It was found that the extractant (HR) is apt to dimerize in
n-heptane diluent. It was clarified that copper and zinc are extracted according to the following equations, respectively, in the low concentration range of the metals.
Cu
2+aq+2(HR)
2, org⇔CuR
2•2HR
org+2H
+aq Zn
2+aq+1.5(HR)
2, org⇔ZnR
2•HR
org+2H
+aqExtraction equilibrium constants, K
e, Cu = 1.0×10
-4 and K
e, Zn=2.5×10
-2 mol
1/2/dm
3/2 were obtained. From the above experimental results, it is seen that selective separation of copper and zinc is possible by solvent extraction with the extractant used in this study.
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MOTOYUKI SUZUKI, AKIYOSHI SAKODA
1982 Volume 15 Issue 4 Pages
279-285
Published: August 20, 1982
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The Dubinin-Astakhov (D-A) equation is modified for adosrption of gases on microporous activated carbons with appreciable size distribution of micropores.
Parameters
n and
E involved in the D-A equation are assumed to vary with the ratio of micropore size to molecular size of adsorbate. Also,
E is considered to be in proportion to the standard heat of vaporization of the adsorbate. The dependence of
n and
E on these characteristics is determined from adsorption data for carbon molecular sieves that have uniform micropores. Thus, once the size distribution function of micropores is given for a commercial activated carbon, adsorption equilibrium of any gas is predictable with the generalized D-A equation proposed here by accounting for the micropore size distribution.
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ULRICH HAUPTMANNS, JAVIER YLLERA, HERMINIO SASTRE
1982 Volume 15 Issue 4 Pages
286-291
Published: August 20, 1982
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The principal mechanisms leading to an explosion of the reactors in a plant for production of nitric acid are represented by means of a fault tree whose numerical evaluation reveals weak points of the safety system and allows its improvement. Both mean values and log-normally distributed failure rates are used, the latter allowing assessment of the influence of the uncertainty of input data on the result for the unreliability of the system.
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KENICHI USHIKI, EIICHI NISHIZAWA, HISAO BENIKO, KOICHI IINOYA
1982 Volume 15 Issue 4 Pages
292-298
Published: August 20, 1982
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The performance and separation mechanism of mist separators, which consist of multi-stage rows of narrow flat plates, are experimentally studied. The effects of stages, blade inclination angle, air velocity, blade pitch and lateral blade dislocation on partial collection efficiencies and on pressure loss are described. The beat design has 30° blade inclination angle and 5 to 7 stages, under conditions of constant pressure loss and of constant blade pitch.
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Ko HIGASHITANI, RYUJI OGAWA, GIJIRO HOSOKAWA, YOSHIZO MATSUNO
1982 Volume 15 Issue 4 Pages
299-304
Published: August 20, 1982
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The coagulation of colloidal particles in a simple shear flow of a viscous fluid is considered. The coagulation rate between unequal spherical particles is calculated by use of approximate trajectory equations, and a kinetic equation of shear coagulation is proposed in which the hydrodynamic interaction between particles is taken into account. It is found that the coagulation rate decreases rapidly with increase of the ratio of particles radius
ai/
aj and a dimensionless quantity 6πμa
3ijγ/
A. Comparison between the present theory and the classical Smoluchowski theory indicates that the Smoluchowski theory is applicable to limited coagulation systems and that it overestimates the coagulation rate considerably when applied to common aqueous dispersions. It is also found that the change of particle concentration is conveniently estimated by a kinetic equation in which the coagulation rate between unequal particles is approximated by that between equal spheres.
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HIROYASU SEKO, SETSUJI TONE, TSUTAO OTAKE
1982 Volume 15 Issue 4 Pages
305-310
Published: August 20, 1982
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Necessary and sufficient conditions for existence of steady states are derived from a mathematical model of fluid catalytic cracker (FCC), and sufficient conditions for stable steady states are determined from the Hurwitz stability criterion by using a linearized FCC model. Based on the graphical analysis of these conditions in a three-dimensional coordinate, a criterion for stability and multiplicity of steady states is developed. By applying the criterion to three kinds of chemical reaction types in the FCC, the stability of steady states can be successfully predicted under various operating conditions.
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HIROYASU OHASHI, TAKUO SUGAWARA, KEN-ICHI KIKUCHI, MORITO TAKEDA
1982 Volume 15 Issue 4 Pages
311-313
Published: August 20, 1982
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IKUHO YAMADA, Soo GAK LEE, SETSURO HIRAOKA, SHIGEHIKO SUDA, MASAO UCHI ...
1982 Volume 15 Issue 4 Pages
313-316
Published: August 20, 1982
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KENJI FUKUCHI, SHIGETOSHI KOBUCHI, YASUHIKO ARAI
1982 Volume 15 Issue 4 Pages
316-318
Published: August 20, 1982
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TATSUYA OKAZAKI, HIROMU HAYASHI, Em KAWANISHI, YOSHIAKI KONISHI
1982 Volume 15 Issue 4 Pages
318-320
Published: August 20, 1982
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HIROMITSU KOJIMA, KOICHI ASANO
1982 Volume 15 Issue 4 Pages
321-323
Published: August 20, 1982
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EIICHI ABE, HIDEHARU HIROSUE
1982 Volume 15 Issue 4 Pages
323-326
Published: August 20, 1982
Released on J-STAGE: April 04, 2006
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