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Volume 5 (1979)
- Issue 6 Pages 547-
- Issue 5 Pages 437-
- Issue 4 Pages 327-
- Issue 3 Pages 219-
- Issue 2 Pages 111-
- Issue 1 Pages 1-
Predecessor
Volume 5, Issue 3
Displaying 1-16 of 16 articles from this issue
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Kenji Haraya, Takashi Nakane, Hiroshi Yoshitome1979 Volume 5 Issue 3 Pages 219-224
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSUnbleached kraft pulp-washing waste water forms a self-rejecting membrane dynamically on a porous support when the waste water is circulated under pressure through the support. Hyperfiltration property of the self-rejecting dynamic membrane was studied using a flow cell and a batch cell at 40 kgf/cm2, 25°C. Because the dissolved lignin in the feed waste water was aggregated in the acidic range, membrane formation and treatment of the feed waste should be performed at pH values outside this range. In the case of feed waste containing NaCl, solutes rejection decreased. By proper selection of conditions, the rejection of TOC, lignin and colored matter and electric conductivity could be maintained for at least 70 hours above 93%, 98.5%, 99% and 80% respectively. Under the same conditions the water flux declined from 4.5 m3/m2·day to 1.3 m3/m2·day. However, the water flux was restored to 85% of that at the initial stage by membrane regeneration.
Furthermore, concentration testing was conducted until 80.3% water recovery was achieved. At this time, total recovery of TOC and lignin reached about 83% and 97% respectively. The quality of permeate water at 80.3% water recovery was comparable to that of low-pressure reverse osmosis testing.View full abstractDownload PDF (1227K) -
Yuji Yoshimura, Kozaburo Ueda, Fuyuhiko Mori, Naoya Yoshioka1979 Volume 5 Issue 3 Pages 225-231
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSInitial filter coefficients used to evaluate the efficiencies of clean deepbed filters in removing suspended particles were estimated by trajectory calculations using Kuwabara's flow model. Under the conditions where double-layer repulsion forces were negligible and contribution from collection by Brownian diffusion was small, the experimental results were in fairly good agreement with trajectory calculations. Under the conditions where double-layer repulsion forces were not negligible and contribution from collection by Brownian diffusion was small, the initial filter coefficients were predicted with corrected trajectory calculations taking into account collision efficiency factors. The collision efficiency factors are defined as the ratio of the number of suspended particles adhering to the filter media to the total number of contacts between them. Their values were estimated by using the data of adhesive forces between suspended particles and filter media and hydrodynamic forces which tend to detach the adhering particles. It was found that the difference between the usual trajectory calculations and experimental results could be explained to some extent using the corrected trajectory calculations.View full abstractDownload PDF (1238K) -
Kensei Hayashida, Yoshimasa Okuda1979 Volume 5 Issue 3 Pages 232-235
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSA cone-and-plate screwless extruder was improved in such manner that the pressure around the cone rim was kept isotropic, and both intermixing of air bubbles and thermal degradation of polymer were prevented by feeding the fresh polymer melt from a feed extruder and by overflowing the tested melt through 3 overflow valves and a center valve. By measuring the radial distribution of pressure in the improved rheogoniometer the first and second normal stress differences of low-density and high-density polyethylene melts were determined for the temperatures 180°C, 200°C and 220°C and in the more practical shear rate region 20-220 sec-1. The results for the first and second normal stress differences were reproducible. The ratio of the second to the first normal stress differences, which is a measure of reliability of the measured values, was- (0.05-0.09). This is part of the evidence by which these values were shown to be reasonable.View full abstractDownload PDF (603K) -
Hiroshi Yokoyama, Tsuyoshi Sano, Tsutomu Chijiiwa, Ryuji Kajiya1979 Volume 5 Issue 3 Pages 236-242
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSIn the polyethylene terephthalate (PET) condensation process, the reaction byproduct removal rate affects the progress of the reaction, because the polycondensation rate of PET is slow and its equilibrium constant is small. To study the rate of this reaction separately from that of byproduct removal, the influence of temperature, pressure, catalyst concentration, residence time and diffusion surface area on the reaction are taken into consideration in this paper.
Experiments were carried out with a 0.5 t/day continuous polycondensation pilot plant. Using a complete-mixing tank-series model with back mixing of the horizontal reactor, the number average degree of polymerization (DP) obtained in the present experiment was found to be in good agreement with calculated values.
The activation energy of the degradation reaction was larger than that of the polycondensation reaction. Considering quality, the production temperature 280-285°C is too high to produce PET. But pressure reduction has influence on the polycondensation without affecting the degradation.
The calculated value deviation of DP from the experimental data were found to be within±5%.View full abstractDownload PDF (1076K) -
Atsushi Inaba, Hakuai Inoue1979 Volume 5 Issue 3 Pages 243-249
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSKinetic studies were made for the thermal degradation of polystyrene at 350°C and different pressures. The degradation rates determined from the amount of oily products were strongly dependent on the agitation speed and the initial load as well as on the operating pressure. The effects of these operating conditions can be explained by the change of mass transfer resistance from the molten polymer to the gaseous stream.
A kinetic model was constructed by taking degradation of the polymers, polymerization of the products and mass transfer resistance into consideration. The results computed from this model agree with the experimental ones.View full abstractDownload PDF (1171K) -
Mitsuo Kamiwano, Kimio Ohya, Toshimichi Koga1979 Volume 5 Issue 3 Pages 250-255
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe mixing of highly viscous Newtonian fluids in two coaxial cylinders was studied to describe the mixing of highly viscous fluids in a stirred vessel analytically and quantitatively.
Two coaxial cylinders in which tangential flow is predominant were used in this experiment. An aqueous polyvinyl alcohol solution which behaved as a Newtonian fluid, especially in the low-shearing-rate region, was used as the mother liquid; an aqueous cobalt chloride (a colored, low-molecular weight) solution was mixed into it.
The mixing process was studied by photographing and analyzing the degree of blackness of the film with an electrophotometer.
The results obtained show that the mixing of highly viscous liquids occurs through diffusion of molecules as well as by convection of liquids. As a result, the mixing process can be explained by an analytical description of the mixing of highly viscous liquids.View full abstractDownload PDF (1037K) -
Satoru Kobayashi, Sakae Kushiyama, Yoshihiro Iida, Noriaki Wakao1979 Volume 5 Issue 3 Pages 256-262
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe effect of the physical properties of liquids on the flow characteristics and flow mixing in packed beds-two phase downflow system was investigated in the range of relatively low gas velocity.
The change in flow pattern from gas-continuous to pulse flow was found to occur at liquid velocity 2 × 104 kg/m2 ·hr in air-water system, and at lower liquid velocity in air-glycerol (25%, 50%) and air-methanol (40%) systems. The liquid velocity at which the change of flow pattern occurs depended largely upon liquid viscosity.
The liquid hold-up for gas-continuous flow was correlated with Re and Ga numbers, irrespective of the physical properties of liquids, and for pulse and bubble flow it was well expressed in terms of parameter χ. In the latter case, the axial dispersion was almost identical with that in single-phase water flow. The axial dispersion in gas-continuous flow was correlated with Re and Ga numbers.View full abstractDownload PDF (1129K) -
Akinori Matsuura, Yosatomi Hitaka, Takashi Akehata, Takashi Shirai1979 Volume 5 Issue 3 Pages 263-268
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSRadial effective thermal conductivity and apparent wall heat transfer coefficient were measured from temperature profiles in cocurrent air-water downflow through beds packed with glass spheres of 3 different sizes (0.12-0.43 cm). This paper concerns the effective thermal conductivity.
In the range of low liquid flow rate, a stagnant effective thermal conductivity, which was independent of gas and liquid flows, was predominant. In the range of high liquid flow rate, heat transfer by lateral mixing of liquid predominated. Effect of gas flow on the effective thermal conductivity appeared only for the conditions of low liquid flow rate and high gas flow rate.
The effective thermal conductivity was correlated by employing a heat transfer model which took into account stagnant effective thermal conductivity and heat transfer by lateral mixing of gas and liquid, as in the following equation :
ke/kl=1.5+ (αβ) g (GgCpg*dp/kl) + (αβ) l (GlCpldp/kl)
where (αβ) g was expressed as a function of particle diameter alone, and (αβ) l as a function of particle diameter and gas Reynolds number based on the superficial velocity.View full abstractDownload PDF (1094K) -
Akinori Matsuura, Yosatomi Hitaka, Takashi Akehata, Takashi Shirai1979 Volume 5 Issue 3 Pages 269-274
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSRadial effective thermal conductivity and apparent wall heat transfer coefficient were measured from temperature profiles in cocurrent air-water downflow through beds packed with glass spheres of 3 different sizes (0.12-0.43 cm). This paper concerns the apparent wall heat transfer coefficient.
In the range of low liquid flow rate, the apparent wall heat transfer coefficient increased slightly with gas and liquid flow rates. In the range of high liquid flow rate, it depended only on liquid flow rate and increased with it.
The apparent wall heat transfer coefficient was analyzed based on a heat transfer model which accounted for heat transfer related to gas and liquid flows and for that independent directly of gas and liquid flows. For the former, equations obtained in previous work were applied, and terms expressing the latter were determined from experimental data. The heat transfer independent of gas and liquid flows was correlated well in terms of dynamic holdup by empirical equations, which depended on particle diameter.View full abstractDownload PDF (1047K) -
Shigeharu Morooka, Yoichi Maruyama, Ken-ichi Kawazuishi, Shun-ichi Hig ...1979 Volume 5 Issue 3 Pages 275-280
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe local weight-mean diameter, the local holdup of solid particles and the heat transfer coefficient between a bed and a vertically inserted tube wall were measured in a 12 cm I.D. fluidized bed using FCC particles with a broad size distribution. The weight-mean diameter of FCC particles was 65 μm and the minimum fluidization velocity was about 0.25 cm/sec.
In a dilute zone which is formed above a bubbling dense zone, the local weight-mean diameter and the local holdup of particles decrease with distance from the upper surface of the dense zone and increase with increasing gas velocity. At a gas velocity of 50 cm/sec there is no notable difference in the weight-mean diameter of particles throughout the bed, but a longitudinal holdup distribution of particles still exists.
The heat transfer coefficient is a function of holdup of particles, weight-mean diameter of particles, gas velocity and physical properties of gas and solid, and is independent of tube diameter.
An empirical equation for the heat transfer coefficient is obtained.View full abstractDownload PDF (1090K) -
Takaji Akiya, Norio Takeuchi, Masaru Owa, Shigetake Kawasaki1979 Volume 5 Issue 3 Pages 281-287
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe sodium hydroxide solution produced by diaphragm cell electrolysis of saturated brine contains some sodium chloride and potassium hydroxide as impurity. For the purpose of purification of the sodium hydroxide solution and concentration of potassium hydroxide in the solution for potassium recovery, the crystallization of NaOH·3.5H2O from the NaOH-KOH-H2O system was investigated using a continuous mixed-suspension mixed product-removal crystallizer and the crystal growth rate of NaOH·3.5H2O was examined by the growth rate equation obtained from the heat and mass balance at the growing crystal surface.
As the result, it was found that crystal growth rate followed the ΔL law and was proportional to the degree of supercooling, and that the surface reaction step was the rate-determining step in crystal growth under these experimental conditions. The nucleation rate was found to depend on secondary nucleation and was correlated with suspension density and crystal growth rate.View full abstractDownload PDF (2840K) -
Ryuzo Ito, Yushi Hirata, Kenichi Inoue, Yoichi Kitagawa1979 Volume 5 Issue 3 Pages 288-292
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe volume of drop detached from a vertical nozzle was measured in two flow systems where the continuous phase with uniform velocity flows parallel or normal to the nozzle axis. Smaller drops were formed in the latter case under the same operating conditions. In the case of low feed rate of dispersed phase, the mean volume of drops could be correlated with a single operating parameter We based on the balance of forces, i. e., buoyancy, surface tension, inertia of dispersed phase and drag by continuous fluid, acting on a drop just before detaching from the nozzle. It was found that the distribution of volumes of dispersed drops obeys the normal distribution function and that the dependency of the standard deviation on Reynolds number corresponds to that of the drag coefficient for the drop calculated from the force balance.View full abstractDownload PDF (730K) -
Kunihiro Kitano, Kazuo Endoh1979 Volume 5 Issue 3 Pages 293-297
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe overall mass transfer coefficient to an oscillating sphere were measured with an electrochemical method. The results were correlated in terms of the Sherwood number Sh and the Reynolds number Re by the following equations :
at 0.2 < a/d ≤ 2.95 20 ≤ Re≤ 46, 000
Sh = 5.64Re0.54whenSc = 1, 660
and at a/d < 0.2 20 ≤ Re ≤ 10, 000
Sh = 8.21/ Re0.40 when Sc = 1, 660
where a is amplitude of vibration, d is diameter of sphere and Sc is the Schmidt number.
It was found that the difference between these mass transfer rate correlations was due to the change of inner circulation flow behavior around the sphere.View full abstractDownload PDF (753K) -
Yoshikazu Miyake, Wataru Eguchi, Motonari Adachi, Susumu Ohara1979 Volume 5 Issue 3 Pages 298-303
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSAbsorption rates of I2 vapor into aqueous NaOH solutions were measured using a flow-type agitated vessel with a constant contact surface area. Observed absorption rates were interpreted by the absorption mechanism considering that the following three reactions, (a) I2+ OH-_??_HIO+ I-, (b) 3HIO→ IO3- +2I-+ 3H+, and (c) I2+ I-_??_ I3-, take place together with the dissociation of both NaOH and H2O. All reactions mentioned above except reaction (b) can be treated as instantaneous reversible reactions. Rate of reaction (b) is so slow that this reaction is regarded to occur in the liquid bulk phase, and consequently the effect of this reaction on the absorption rate becomes gradually significant with increase in residence time of the liquid phase.
There are, however, two different patterns of change of the enhancement factor due to reaction (b). Firstly, the enhancement factor increases with the progress of IO3- formation under the conditions of high NaOH concentration and low I2 vapor concentration. Under the opposite conditions, on the other hand, the enhancement factor decreases to a value lower than that estimated when reaction (b) is neglected. This decrease results because reaction (a) is restrained by a considerable decrease in the concentration of OH-, which in turn is caused by an increase in the concentration of H+ produced by reaction (b).View full abstractDownload PDF (1302K) -
Takeshi Sako, Kenji Haraya, Yuji Shindo, Kenzaburo Obata, Toshikatsu H ...1979 Volume 5 Issue 3 Pages 304-307
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSThe vapor pressure of liquid iodine was measured from 116.2 to 263.2°C (100.83808.0 mm Hg) in this work. This is not only a fundamental thermodynamic property, but also very important for designing and operating the hydrogen production process by the magnesium iodine cycle for the thermochemical decomposition of water. There were a few data below the normal boiling point (184.5°C), but no data above atmospheric pressure (760 mm Hg). Experimental data below the normal boiling point were in satisfactory agreement with the literature values. The vapor pressure data were fitted by the least-squares method to the Antoine equation within an average error of 0.66% and a maximum error of 13.3 mm Hg. The normal boiling point and the latent heat of vaporization calculated from the data of this work agreed very well with literature values. The vapor pressure data were compared with estimated values by use of the acentric factor (ω) to confirm the consistency of the experimental data, and the two almost coincided.View full abstractDownload PDF (615K) -
Yoshinori Nagashima, Shinichi Maeda, Isami Yoshifuku, Ryuzo Ito, Yushi ...1979 Volume 5 Issue 3 Pages 308-326
Published: May 10, 1979
Released on J-STAGE: October 21, 2009
JOURNAL FREE ACCESSDownload PDF (4418K)
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