Agitation power were measured in agitated vessels with highly viscous liquids under conditions of aeration and non-aeration. The agitation power data obtained in the absence of aeration were empirically correlated by the use of two traditional parameters, i.e., power number and Reynolds number.
The agitation power required under aeration were also correlated based on the consideration of the relationship between the power and the shape of the cavity formed behind the impeller blade.
Apparent volumetric mass transfer coefficients were measured with the assumption that the liquids in the vessels remained in a state of the perfect mixing. In the region where the agitation power is relatively great, the relationship between the mass transfer coefficient and the agitation power could be shown by straight lines in log-log plots. In this region, a simple correlation equation was proposed for the mass transfer coefficient. In the region where agitation power is not so great, on the other hand, the mass transfer coefficients were shown to be estimated well by the use of the above-mentioned correlation equation and the correlation equation proposed for bubble columns (Tokanai et al., 2001).

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When the length of an annular liquid film in a circular pipe exceeds a critical length under zero gravity, the liquid film breaks into several lobes periodically, and plugs are formed. The behaviors of the interface deformation of the liquid films and plug formation under microgravity were investigated using the drop-shafts of Hokkaido National Industrial Research Institute (HNIRI), Microgravity Laboratory of Japan (MGLAB) and Japan Microgravity Center (JAMIC). The glass pipes were installed horizontally and vertically.
The experimental and numerical results of the average wavelength of the lobes spaced along the pipe were in good agreement with those of the linear stability analysis.

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The effects of fuel particle size on the combustion propagation rate of the reverse combustion in a packed bed were studied experimentally. We used spherical pellets of activated carbon having a size range of 2.8–6.7 mm. Superficial air velocity was set in the range of 0.012–0.165 m/s. The experimental results showed that in the lower gas velocity region, the combustion front propagation rate increased with the air velocity independently of the particle size. However, at air velocity beyond a certain value, the propagation rate took an asymptotic value that increased with decrease in the particle size.

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A 150 ton/day coal liquefaction pilot plant (PP) of the NEDOL process, supported by New Energy and Industrial Technology Development Organization (NEDO), was operated successfully for a total of 269 days at Kashima, Japan. With a great number of data obtained through the operation, the design procedure for the NEDOL process was studied. Middle and heavy oils from the coal employed were recycled as a hydrogen-donor solvent after hydrotreatment over Ni-Mo/γ-Al₂O₃ in a trickle bed reactor. The hydrogen donating ability of the solvent was high enough to obtain higher oil yield (50~58 wt%) at the aromaticity of ca. 0.45. Life expectancy of solvent hydrotreatment catalyst, requisite to the hydrotreater design, was estimated under PP operating conditions. In addition, physical properties of the solvent required for process design were determined, and hydrodynamics in the liquefaction bubble column reactors were examined. Taking the obtained hydrodynamics and thermal behavior into consideration, we established a design procedure of the liquefaction bubble column reactors using a process simulator (CARD) validated by the product yields of PP. The simulation including distillation and solvent hydrotreatment showed that the content of heavy oil fraction (b.p. 350–538°C) in the solvent was a determinant factor in the design of a large-scale plant based on the NEDOL process.

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Aluminum hydrazinium sulfate (AHS) double salt supported on sepiolite has been found to show good adsorption characteristics for acetaldehyde. However, hydrazine is believed to be carcinogeric and is to be used with great care. This study focused on thermal cracking characteristics of AHS adsorbent and showed that no emission of hydrazine was identified. The composition of emitted gases changed upon the adsorption of acetaldehyde, but it was estimated that hydrazine was easily decomposed into nitrogen and ammonia before desorption from the support. From the amount of water generated during heat treatment, acetaldehyde is estimated to be in the form of acetaldazine when trapped on the adsorbent.

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We investigated the effect of fly ash content on the synthesis of zeolites from coal fly ash prepared by hydrothermal treatment. Both phillipsite and hydroxysodalite are synthesized from fly ash of relatively low silica content. It is found that only phillipsite is synthesized selectively by hydrothermal treatment when concentration of silicate ion is higher than that of aluminate ion in NaOH solution.
We proposed and formulated the formation mechanism of phillipsite. Silicate and aluminate ions dissolve in NaOH solution from fly ash and form aluminosilicate, from which phillipsite crystal are generated. The changes in ion concentrations and phillipsite mass calculated by the newly proposed model agrees with the experimental results. It is suggested that the critical concentration of crystallization and the rate constants of gelation and crystallization are constant, independent of fly ash morphology.

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Epoxy resin (Ep 850)/acrylic composite latex was prepared by a miniemulsion polymerization method. The effects of preparation conditions, such as homogenization time and amount of anionic or nonionic emulsifiers and costabilizer, on droplet size of the monomer-miniemulsion were investigated. The longer the homogenization time and the larger the amounts of emulsifiers, the smaller the droplet size of the monomer-miniemulsion became. If the homogenization time was long enough, the amounts of emulsifiers correlated to the droplet size of miniemulsion. The larger the amount of costabilizer, the better the stability of monomer-miniemulsion became.
The effects of droplet size of the monomer-miniemulsion on properties of the obtained latex, such as particle size of the latex, solvent resistance of its films and solubility in tetrahydrofuran (THF), were also investigated. When the droplet size of the monomer-miniemulsion was large, the particle size of the obtained latex was smaller than the droplet size of monomer-miniemulsion. On the other hand, when the droplet size was relatively small, the particle size of the obtained latex was almost the same as the droplet size. Comparing the solvent resistance or solubility in THF of these latexes, the epoxy groups of the former were lost more quickly than those of the latter. Thus miniemulsion preparation conditions strongly affect the properties of obtained latex.

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We attempted to wash liquid paraffin trapped in a porous polyethylene film by microemulsions formed in a polyoxyethylene-type nonionic surfactant system. Detergent efficiency reached the highest value, approximately 90–95%, in the case of the high oil-to-water ratio in microemulsions, but failed to reach the highest level when the oil content in microemulsions was low. Washing time required to reach the highest detergent efficiency was shorter with a short-chain surfactant than a long-chain one, but the highest detergent efficiency was higher with the long-chain surfactant, about 90% in the C₁₀EO4 system and 95% in the C₁₆EO₇ system. The detergent efficiency with a mixture of long and short-chain surfactants was lower than that with a long-chain surfactant alone. The high detergent efficiency with the microemulsions of high oil content is thought to be due to low interfacial tensions at the liquid paraffin-microemulsion and polyethylene-microemulsion interfaces; and the short washing time with short-chain surfactant is thought ot be due to the small size of micro domain inside the microemulsions.

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A simulation method of initial-stage sintering was proposed to understand the effect of sintering conditions on the sintering behavior of two particles of different size and composition. In this study, This study employed a homogeneous solid solubility system of Cu-Ni. The sintering experiments were performed with two spherical Cu-Ni particles in contact, and the sintered particles were observed by SEM and EDX. It was confirmed that the sintered particles always form a curved neck and copper was the dominant component in the neck.
The proposed simulation method, in which the model for two particles of identical composition was modified, involves several mass transport mechanisms : surface diffusion, volume diffusion, grainboundary diffusion-evaporation-condensation and newly, grain growth. The sintering behavior of CuNi particles was simulated using the proposed method and the results agreed well with experimental ones. It was also found that grain growth was not negligible in initial-stage sintering, and that shrinkage and grain growth responded sensitively to sintering conditions. Consequently, by analysis of these simulation results, it is possible to understand the mechanism of sintering of two spherical particles of different composition and to determine the best sintering conditions.

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The purpose of this study is to specify the scale-up factor and to establish a scale-up method for the vibrating membrane separation system. The permeate flux of latex solution was measured using both a small-scale model system (after here S-system) and an industrial-scale system (after here I-system). The results showed that the permeate flux in the S-system was larger than that in the I-system. The difference was considered to be caused by two reasons. The first is that the shear rate given to the fluid near the membrane surface of the S-system was bigger than that of the I-system because the vibrating frequency of the S-system was higher than that of the I-system. The other is that the I-system used multi -layered membranes of lauger radius than the S-system, while the S-system used only a single membrane. Therefore, the concentration in the membrane module of the I-system varied in the flow direction, and this results in the smaller averaged permeate flux in the I-system. Based on these facts, a scale-up method for predicting the permeate flux in the I-system from that in the S-system was proposed. The predictions of the permeate flux by the method were well consistent with the measurements within an error of 5%. Furthermore it was found that it is possible to use the shear rate applied in the fluid near the membrane surface as a scale-up factor of the vibrating membrane separation system.

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Convective and conductive-convective drying experiments were performed by using a glass particle layer wetted with aqueous polyvinylalcohol (PVA) solution. Drying rate and PVA content profile of dried sample were measured. PVA content was higher near the drying surface only in the case of convective drying, and higher at both the drying surface and the bottom of the sample in the conductive-convective drying. The PVA content near surface was higher in the convective than in the conductive-convective drying, which showed the higher drying rate.

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Double-sided convective drying was performed by using a glass particle layer wetted with aqueous polyvinylalcohol (PVA) solution or water. Two systems were prepared, one having the wet layer laid directly on a porous layer, and the other having a polymer sheet inserted the layers to block moisture transfer. The drying rate and PVA content profile of dried system were measured for each system. When the glass particle layer was wetted with PVA solution, the drying rate in the system allowing free transfer between the layers was larger than that in the system in which transfer was blocked. When the glass particle layer was wetted with water, the reverse result was obtained. The increase in drying rate in the former case may be due to a decrease of PVA content near the surface because of infiltration of PVA solution inte the porous layer during drying.

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Experimental and theoretical studies have been conducted about the influence of particles and dispersion medium behavior in the sedimentation bath on the measurement of particle size distribution with the sedimentation balance.
It is found that an increase in the height of the peripheral wall of a detective tray raises the velocity of the downstream outside the tray and lessens the particle movement in the radial direction. Hence, the initial gradient of a sedimentation curve is larger than that of the theoretical line, and the total sedimentation mass agrees with the theoretical value.
Since the velocity of the downstream outside the tray decreases with decreasing diameter of the tray, both the gradient and total mass come close to the theoretical value. It is found that the size distribution can be measured more accurately by using a detective tray whose diameter is smaller and peripheral wall is higher. Furthermore, it is suggested that the numerical simulation proposed in this paper can optimize dimensions of the sedimentation balance type particle size analyzer.

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Electrostatic particle deposition using tribo-electrification was examined in an experimental apparatus with changeable relative humidity of the particle storage section. The specific charge on particles was found to be controllable to some extent by changing average air velocity in the supply pipe and relative humidity in the storage section. The charged particles did not deposit initially on the front edge of the target because of an inertia effect, especially when a low voltage applied to the target; They deposited initially on the rear and side edges of the target, and as time elapsed, they gradually deposited on the central region of the target. The result suggests that the strength of the electric field may be decreased by the deposited charged particles. The average thickness of deposited particles increased with time elapsed and approached a constant value. The time constant for particle deposition did not depend on the voltage applied to the target. The coefficient of variation for particle deposition decreased with time elapsed and applied voltage, but it changed little after a certain of time had elapsed. It was found that there exists an optimum relative humidity in the particle storage section for deposition of charged particles on a target.

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Surface modification of ash powder was conducted to achieve better control of its mechanical properties in an ash-handling process. Flyash powder (JIS 10) was selected as a powder sample, and carbon black was selected as a fine particle. The powder was mechanically coated with fine particles. As a result, the fluidity of the powder was improved by adding a small amount of fine particles at room temperature. Addition of the fine particles also decreased the tensile strength of the flyash powder bed, and changed the displacement needed for the breakage of the powder bed.

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A process was developed for production of charcoal bricks from spent grain from a beer brewery, and the physical and chemical properties of the charcoal bricks roduced were evaluated. The beer spent grain (water content 67 wt%) was first dried, then pressed at high temperature and pressure to make bricks without any binder. Finally, the spent grain bricks were carbonized in a low oxygen atmosphere to produce charcoal bricks.
The heat recycling carbonization method, in which a part of carbonization gas output was returned to the carbonization furnace, was applied to the carbonization of the bricks. This method yielded charcoal bricks with a constant quality and high yield. The charcoal bricks had a high calorific value of about 27 MJ/Kg, which was equipollent to that of Bincho-tan and was about 13% lower than that of Oga-tan. The contents of nitrogen and phosphorus in the charcoal bricks were 9–20 times and 40 times greater than those of Bincho-tan and Oga-tan, respectively. As the spent grain charcoal bricks contained various minerals such as calcium, magnesium and phosphorus, they had the possibility to be used as a source of natural minerals.

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An unsteady model of the combustion of a single RDF pellet, which involves heat transfer and oxygen diffusion in the RDF pellet, was developed to interpret quantitatively the devolatilization and the char combustion processes of RDF. The simulation results for weight loss and temperature profile of the RDF samples made from municipal solid wastes, wood chips and polypropylene when they were heated at 10 K/min or put into the furnace at 1,073 K were verified to agree with the experimental data. Moreover, by analysis of the temperature distribution and the conversion rate along the radius of the RDF pellet during the devolatilization process and the char combustion process using this model, the influence of heating rate on the combustion characteristics was clarified.

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