-
Toshinori Kojima, Tadashi Kimura, Masayuki Kurimoto, Takaya Nakagawa, ...
1995 Volume 21 Issue 2 Pages
241-247
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Diatomaceous earth particles were calcined in an entrained bed and a powder-particle-fluidized bed using spherical alumina particles as bed materials. Air was usually used for their calcination. Oxygen gas wa necessary to remove the organic material included in the particles because the color of particles calcined in a nitrogen gas stream changed to black 40 min. was enough for at the calcination time 1173 K from fluidized bed experiments. In the entrained bed results, the loss on ignition of diatomaceous earth particles was decreased with an increase in the bed temperature and an increase in the residence time. The calcination was terminated in several seconds at 1473 K. The particles were not granulated during the process. A filtration test of the calcined particles indicated that the shells of the particles were not destroyed. These results in dicated that this process can be applied for lower grade raw material. In conclusion, fluidized bed and entrained bed processes were found to be applicable to the calcination of diatomaceous earth as alternatives to the conventional rotary kiln process.
View full abstract
-
Hiromoto Usui, Takashi Saeki, Tsuneo Takagi, Keiji Tokuhara
1995 Volume 21 Issue 2 Pages
248-256
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The addition of cationic surfactant causes significant drag reduction in a fluid transport line of a district heating and cooling system. The scale up data for a fluid transport system with a well known effective additive were obtained in this study. Also, a simplified calculating method to predict the power consumption in the surfactant drag reducing system was proposed. Many aspects of the practical problems which are encountered in the application of surfactant drag reduction technology were experimentally discussed and it was certified that the addition of surfactants to the practical district heating and cooling system caused no problem.
View full abstract
-
Kooji Kagara, Shigeru Ieda, Hironobu Yasuda, Muneharu Ikushima, Shunsu ...
1995 Volume 21 Issue 2 Pages
257-264
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Trialkyl urea exists in three polymorphic modifications, stable A, metastable B and unstable C. In order to produce metastable B, the crystallization behavior of this compound in toluene was investigated using an infrared spectrometer. In the case of crystallization temperature at 318 K and 333 K, B, mixtures of A and B or A crystallized initially corresponding to the degree of supersaturation
SB. But crystallized B transformed to A after some elapsed time. C cyrstallized at 298 K independently of
SB and transformed to A.
The effects of crystallization conditions on the transformation rate constant κ from A to B and on the waiting time θ
B for the nucleation of B-form were investigated using a 500-m
l crystallizer. Furthermore, the detailed crystallization conditions for large-scale production were determined using a 2
l and 200
l crystallizers.
On the basis of these results, metastable B free from stable A was produced in a 200
l crystallizer.
View full abstract
-
Shigeo Ito, Satoshi Kawamura, Shigenori Komura
1995 Volume 21 Issue 2 Pages
265-271
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Although porous ceramic filters are promising device for coal gas cleaning, it is necessary to maintain stable base line pressure loss, which is the pressure drop of the filter just after reverse cleaning. As penetration and covering of the filter pores by coal char increase the pressure loss, a method to recover the permeability by removing the particles was investigated.
The ignition temperatures of some coal chars were lower than 773 K. A regeneration test of a used filter showed that the filter temperature could also be kept at lower than 773 K during char combustion because the residual amount of char was small. In a filter recycle test, the base line pressure loss recovered after every regeneration cycle and the residual ash on the filter seemed to protect the filter surface from dust particles. Therefore, this regeneration method may improve the filter durability effectively.
View full abstract
-
Sachio Okayasu, Takahiro Kuratani, Hiroshi Imai
1995 Volume 21 Issue 2 Pages
272-278
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Automatic control of incinerators for their stable operation has been desired for the preservation of the environment in the factory. An on-line fuzzy control system has been successfully introduced for temperature control of the fluidized bed of incinerator for industrial wastes. In this case, manual control can be applied to the plant instead of a PID control system, because of the complexity of the waste materials and the large delay in detection of the temperature change in the fluidized bed sand. On the basis of analyzing the dynamic performance of the process and the know-how of skilled operators, membership functions and fuzzy control rules are selected, then determined carefully for the system. Introduction of the system resulted in almost the same performance as manual control. Subsequently the operators are freed from manual operation in the control room for an hour.
View full abstract
-
Yoshiyuki Bando, Makoto Nishimura, Hiroshi Hayakawa, Nobuyuki Kawase, ...
1995 Volume 21 Issue 2 Pages
279-285
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
To give a role of immobilizing carrier to a draft tube, a packed double perforated draft tube was proposed and the liquid mixing and gas-liquid mass transfer of a bubble column with this type of draft tube were examined. The packed double perforated draft tube consisted of two different-diameter perforated tubes and the space between two tubes was filled with particles. Under various combinations of inside and outside diameters of draft tubes and particle diameter, the flow pattern was observed and the liquid mixing time, gas holdup and volumetric mass transfer coefficient were measured.
When the packed double perforated draft tube was used, a part of gas and liquid flowed radially through the particle layer and large bubbles were then subdivided into fine ones. For the liquid mixing time, gas holdup and volumetric coefficient, the diameters of particle and draft tube had optimum values. From comparison of the flow characteristics of the proposed type with those of conventional bubble columns, it was found that the packed double perforated draft tube was effective for the improvement of liquid mixing and gas-liquid mass transfer, especially when the bubble size was relatively large.
View full abstract
-
Hideaki Kurokawa, Toshio Sawa
1995 Volume 21 Issue 2 Pages
286-293
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A simulation model, using a mass transfer coefficient which has as its driving force humidity difference and a heat transfer coefficient which has as its driving force enthalpy difference, is developed for investigating operation characteristics of membrane distillation. Optimum conditions are calculated by the model and the calculated results are proved by actual experiments. Simulated results show that the higher the feed input temperature and the cooling water input temperature, the smaller the recycling rate, membrane area and heat energy are. For a system which has a 0.216-m
2 membrane and heat exchange area, optimum conditions of feed input and cooling water input temperature and recycling rate are 90°C, 50°C, and 18.5 kg/ h, respectively. Furthermore, an actual experiment was performed and its permeate rate and heat input were 1 kg/h and 0.21 kW ·h. From the work, the latent heat recovery is seen as about 66% and the simulation model-reliability is verified.
View full abstract
-
Eiichi Kunugita, Yoshiro Inoue, Jong-Hwa Kim, Izumi Tsuboi
1995 Volume 21 Issue 2 Pages
294-299
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A relational database (keys : ions and precipitates, attributes : reagents to be added, records : chemical species produced by adding reagents) is constructed, based on information about deposition and dissolution of precipitates which are described in the literature.
A computer-aided method for synthesizing metal separation processes by precipitation is established. Processes for separating metals in leaching solution of fly ash discharged from furnaces used for burning municipal wastes are synthesized. A feasible process is tested experimentally. The result shows that the process has ability to separate metals, cadmium, copper, manganese, lead and zinc from each other. More studies are needed, however, on the optimum operating condition.
View full abstract
-
Keisuke Fukui, Satoshi Syoya
1995 Volume 21 Issue 2 Pages
300-305
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The organization process of turbulent structure was investigated, using the conditional-average technique, in unstably-stratified and mixed-stratified turbulent flows developing between horizontal parallel plates. As to the unstable flow, a small organized-vortex, which appeared near the lower plate heated from below, grew to a large-scale longitudinal vortex which was expanded up to the upper plate. In the mixed stratified flow, upward motion which occurred within the unstable layer reached as far as the stably stratified layer near the upper plate and caused the turbulent longitudinal vortex. The shape of the vortex changed because of the span-wise motion near the upper plate. It was also confirmed that two organized vortices were formed in the thin fluid layer near the upper and lower plates as the large longitudinal vortex was growing.
View full abstract
-
Shinichiro Gondo, Hidekazu Koya, Mitsuyasu Kawakami
1995 Volume 21 Issue 2 Pages
306-311
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Amino groups were attached to a platinized platinum electrode through alkylamine-silanization. Glucoamylase (GA) and glucoseoxidase (GOD) were then immobilized directly onto the platinum electrode. The immobilized two enzyme electrode (GA-GOD-Pt) was coupled with a Ag/AgCl electrode as its counter electrode and its characteristics as a maltose sensor were investigated. An increased linearity was observed as the pH value of the ambient solution increased. Its tendency of increased linearity with increased pH value toward 7.5 was examined through the aid of theoretical analysis of the relation between electrode current and maltose concentration and the use of the GA-GOD-Pt electrode under conditions of somewhat depressed GA activity was recommended. The dynamic response of the GA-GOD-Pt to the stepwise change of maltose concentration was found to be expressed by a first order response model without time delay.
View full abstract
-
Atsumi Miyake, Takashi Uchida, Terushige Ogawa, Yuzo Ono
1995 Volume 21 Issue 2 Pages
312-318
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
In order to investigate the thermal decomposition characteristics of cumene hydroperoxide (CHP), thermal analysis (DSC), adiabatic/isothermal storage tests and chemical analyses were carried out.
It was found that the thermal stability of CHPs was strongly influenced by their concentration and the thermal decomposition of concentrated CHPs were stimulated with the organic acids which were produced during the decomposition process of CHPs.
From the results of isothermal storage tests in closed vessels, pressure rises were observed and the thermal decomposition proceeded, even in the range where temperature rises were not observed. Pressure monitoring of gas evolution should also be carried out for evaluation of thermal stability of CHPs.
View full abstract
-
Yoshio Nakano, Yoshimi Seida
1995 Volume 21 Issue 2 Pages
319-326
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A change of pH inside a polymer hydrogel was induced through electrochemical control of proton production to release the water from inside the gel. The relationship between release rate of water and operating conditions such as applied voltage, electrolytes and solution pH were studied experimentally and the following results were obtained.
The release rate of the water from inside the gel,
vt was controlled by both applied voltage and addition of electrolyte. The release rate increases depending on the applied voltage that promotes the production of H
+ ion. The additive electrolyte increases the release rate with its concentration because of the increase of electric conductivity of the solution, resulting in an increase of H
+ ion production. The addition of alkali, however, decreases the release rate depending on the pH.
The release rate can also be controlled by supplied charge, because there is a stoichiometric relation between the amount of charge and H+ ion production. The release rate based on charge,
vq, means the efficiency of charge (proton consumption) in the release of water from inside the gel. The
vq depends on the electrolyte and/or the concentration of counter ion inside the gel.
View full abstract
-
Junji Shibata, Hiroshi Tokunaga
1995 Volume 21 Issue 2 Pages
327-333
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Removal of organic compounds from an aqueous solution has been studied using solvent sublation. The organic compounds are mono-chlorobenzene, tri-chlorobenzene and naphthalene. They are removed at high efficiency by solvent sublation, because they are hydrophobic and have low vapor pressures. A model for the removal mechanism of the organic compounds from an aqueous phase is constructed and the removal percentage calculated from the model is compared with experimental results. Removal percentages for the organic compounds, by bubbling and by transfer to the organic solvent in the upper part of the column, are calculated from model equations.
When salts are added in the aqueous phase, the removal percentage of mono-chlorobenzene increases due to the salting out effect. The removal percentage of mono-chlorobenzene is slightly enhanced with addition of ethanol to the aqueous phase, which makes the diameters of bubbles smaller and consequently increases surface area per unit volume of bubble. The addition of salts and ethanol has an effect on the increase in removal percentage of the organic compounds.
View full abstract
-
Kenji Hamada, Mamoru Senna
1995 Volume 21 Issue 2 Pages
334-340
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A description and characteristics of a newly devoloped multiring media mill are given. An empirical equation relating the time needed to accomplish a desired median diameter,
D50, was obtained as a function of the grinding time and the rate of revolution of the rotor supporting the grinding rings. Heavy calcium carbonate was used as a model substance. The change in chemical properties was also examined. The increase in apparent solubility was monitored by pH and the structural degradation by X-ray diffractometry. A non-linear variation was observed and discussed in terms of a decrease in
D50 or an increase in the specific surface area and the solubility.
View full abstract
-
Hideyuki Aoki, Hiroshi Sato, Takatoshi Miura
1995 Volume 21 Issue 2 Pages
341-348
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The thermal stress analysis within lump coke was studied in order to investigate macro-crack formation and deformation behavior which strongly influence heat and mass transfer in a coke oven chamber. The dilatation of plastic layer, heating rate dependence of thermophysical and mechanical properties of coal/coke, creep in the plastic and semi-coke layers, macro-crack propagation and radiative heat transfer within the macro-crack were considered in an analytical model. The macro-crack propagation was determined from the estimated crack tip stress intensity factor,
KI, at the macro-crack tip compared with the plane strain fracture toughness,
KIC, through the unsteady-state calculation. Calculated results on crack formation and deformation behavior of lump coke were in good agreement with experimental observations in a laboratory-scale oven chamber. The analytical model could predict micro-crack formation within the lump coke normal to the heated wall and the coke surface close to the heated wall.
View full abstract
-
Ryuichi Egashira, Takahiro Sugimoto, Junjiro Kawasaki
1995 Volume 21 Issue 2 Pages
349-356
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
In the first stage, an attempt was made to select the type of packing for an emulsion liquid membrane process by permeation experiments with an aromatics non-aromatics binary mixture as an inner oil phase in the emulsion. Mechanical entrainment of a portion of the outer oil phase into the membrane phase, which frequently results in unfavorable phase inversion, was not detected at all with any packing. A packing whose surface is wetted with the emulsion (the dispersed phase) was recommended for this separation technique in order to avoid membrane breakage and to improve separation selectivity, whereas a packing which is not wetted with the dispersed phase is used in an ordinary liquid-liquid operation. Secondly, with the emulsion-wettable packing, further experiments were conducted under various conditions and the mass transfer coefficient was correlated. Major resistance to overall permeation resided in the emulsion. Independently of the feed system and the composition, the dimensionless mass transfer coefficient in the emulsion could be correlated by a simple dimensionless equation with two dimensionless numbers. The mass transfer coefficient for the permeation in the opposite direction (the inward permeation) could also be represented roughly by this equation.
View full abstract
-
Manabu Yamaguchi, Akira Matsui, Hideki Murakami, Takashi Katayama
1995 Volume 21 Issue 2 Pages
357-364
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Formation of uniformly sized droplets in an electric field was investigated experimentally for Newtonian liquids in air. The field was made of a metal nozzle to which a positive DC voltage was applied and an earthed copper plate. Formation of the droplets was carried out in the range of the flow rate of dispersed phase prior to formation of a liquid jet. It was found that the size of fine charged droplets from the nozzle depended significantly on applied voltage and electrical relaxation time of the liquids. The mechanism of droplet formation and the specific charge of the droplets were discussed.
An empirical correlation for the size of the monodispersed droplets is proposed and is useful for Newtonian liquids with a wide range of physical properties; electrical conductivity, permittivity and viscosity. Also, the minimum voltage required for the formation of monodispersed droplets is proposed.
View full abstract
-
Yoshihito Kato, Setsuro Hiraoka, Yutaka Tada, Seiji Shirai, Takafumi U ...
1995 Volume 21 Issue 2 Pages
365-371
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Power consumption and elevated height of liquid surface on the vessel wall
h were measured in horizontally shaking vessels. Complete mixing was attained, when the
Fr number was in the region of
0.135
Re-0.176<
Fr<0.135
Re0.166 (
Re>1)
where
Fr and Re were defined by
N2D/g and
Nd2/ν, respectively. The power number
Np (=
P/ρN3D5) and the elevated height of liquid surface on the vessel wall
h were correlated as follows.
Np=934
Fr3/2Re-1/4 (
d/D)
3/2h/D=14
Fr1.25 (
d/D)
0.37The mixing time by vessel shaking was slightly longer than that by impeller mixing for a particular power consumption per unit volume.
View full abstract
-
Yasuo Kousaka, Yoshiyuki Endo, Takahiro Horiuchi, Yoshiyuki Sasaki
1995 Volume 21 Issue 2 Pages
372-377
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The effect of electrostatic repulsion force arising from the surface potential ψ and the double layer 1/κ around a particle on dispersion or de-agglomeration of agglomerated particles in water is discussed.
Several suspensions of PSL (polystyrene latex) particles in an agglomerated state where and 1/κ are respectively controlled by the pH and the electrolyte concentration
Ce were prepared. They were accelerated in a convergent nozzle to give an external force on particles and agglomerated particles were dispersed into primary particles. PSL particles thus dispersed were observed with an optical microscope. It was found that the dispersion of agglomerated particles was enhanced with an increase of ψ and
Ce under a constant external force or a constant flow rate in the nozzle. It is well understood that the dispersion of particles with higher surface potential ψ is much easier. It is, however, intuitively curious that the dispersion of agglomerated particles in higher electrolyte concentration
Ce is much easier, since coagulation is usually enhanced in such a higher
Ce suspension. The experimental results may be applied to control the dispersion of agglomerated particles in water.
View full abstract
-
Jun Fukai, Hisayuki Orita, Xioashan Yu, Isao Isokawa, Osamu Miyatake
1995 Volume 21 Issue 2 Pages
378-384
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The governing equations of heat transfer and gas flow within a cylindrical porous material which causes thermal decomposition are simplified to derive approximate models for evaluating the inner gas pressure and the effort of the convection heat transfer, respectively. The combination of these models with the existing previous stress model gives a model for not only evaluating the thermal stress but also stress due to gas pressure.
The models are adapted for a green carbon rod during carbonization. The numerical results reveal the following useful facts : 1) Both the gas pressure and the stress due to the gas pressure approximately increase in proportion to specimen diameter and the square root of heating rate. 2) The releases of gaseous tar and H
2 promote the convection heat transfer rate within the specimen because they change the thermophysical properties of the gas phase as well as increase the gas flow rate. 3) The release of H
2 essentially raises the gas pressure and the stress due to the gas pressure and moreover has a particularly strong influence on the overall-stress peak at about 1000 K.
View full abstract
-
Sang-Chul Jung, Nobuyuki Imaishi, Heung-Chul Park
1995 Volume 21 Issue 2 Pages
385-392
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
ZnO thin films were prepared from zinc acetate using a horizontal tube hot-wall CVD reactor under various pressure and the dependency of film characteristics on operating conditions was studied. The profile of the thin film grown on microscale trenches and the macroscopic growth rate distribution along the reactor were studied by micro/macro numerical simulations.
The experimental results indicate that the CVD reaction mechanism changes with operating pressure. A model was proposed to explain the experimental results. The model reveals that, at higher pressures, ZnO film is formed directly from zinc acetate through the slow surface reaction, as was pointed out in our previous paper APCVD. At low pressure, an active species is formed in the gas phase via a gas-phase reaction, diffuses to the reactor wall and deposits ZnO film via a fast surface reaction. At intermediate pressure (10-300 Torr), these two reaction paths coexist but the active intermediate is deactivated through molecular collisions with nitrogen. The experimental results are best, but not perfectly, explained by assuming the rate of the reverse reaction is proportional to C
N23, where C
N2 is concentration of nitrogen.
View full abstract
-
Kenji Mishima, Shigeyuki Nagayasu, Michinori Totoki, Takaharu Uchiyama ...
1995 Volume 21 Issue 2 Pages
393-396
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The partition coefficients of catechol and three kinds of catecholamines were determined in aqueous two-phase systems containing polyethylene glycol (
Mw= 7, 500) and ammonium sulfate at 25°C. It was found that the distribution coefficients of catechol and catecholamines increase with increasing tie-line length and that an approximately linear relationship exists between ln
K4 (
K4=
m4Top/
m4BOT) and tie-line length. The partition coefficients of catecholamine were rather lower than those of catechol.
Further, the osmotic virial equation was used to correlate the partition coefficients of catechol and three kinds of catecholamines.
View full abstract
-
Kenji Mishima, Akihiro Miyake, Kiyoshi Matsuyama, Junji Sugino, Masano ...
1995 Volume 21 Issue 2 Pages
397-401
Published: March 15, 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Vapor-liquid equilibria of aqueous ethanol solutions containing a very small amount of ethyl caproate, isoamyl acetate and 1-propanol were determined using an Othmer-type still at 66.7 kPa. The equilibrium ratio of the minor components increases with decreasing mole fraction of ethanol in the solutions. The results were correlated with the NRTL equation.
View full abstract
-
1995 Volume 21 Issue 2 Pages
e1
Published: 1995
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
-
1995 Volume 21 Issue 2 Pages
e1a
Published: 1995
Released on J-STAGE: November 22, 2010
JOURNAL
FREE ACCESS
-
1995 Volume 21 Issue 2 Pages
e1b
Published: 1995
Released on J-STAGE: November 22, 2010
JOURNAL
FREE ACCESS
