KKI process is a new one for thermal cracking of vacuum residue and employs a particle circulation system between two fluidized beds, using an overflow system.
Considering this particle circulation system, the most important points are to predict the particle circulation rate and to control this rate. The characteristics of fluidization in both vertical and inclined fluidized beds were studied by single fluidized bed mock-up tests in a liquid-solid system (water-glass beads system). The relationships between the superficial velocity and the particle diameter at the same expansion ratio in both vertical and inclined fluidized beds were obtained.

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The effect of cationic polyelectrolyte dosage on both flocculation and dewatering characteristics for municipal sewage sludge was investigated using a commercial-scale continuous belt press.
It was found that :
1) Dewatering characteristics were optimum at a break point, i.e., a polyelectrolyte dosage above which residual polyelectrolyte was observed in separated water.
2) Results of continuous experiments were mostly the same as those of batch experiments for night soil treatment sludge.
3) Residual polyelectrolyte concentration was useful index for the optimal control of polyelectrolyte dosing.

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The correlation of the natural frequency of a bubble swarm in water with the bubble diameter was studied experimentally. Measurements of the frequencies F_n of a bubble swarm were made by using the pulse response method of sound. The natural frequencies F₁ of a bubble in the swarm, supposing that there was only a single bubble in water, were obtained by the floating bubble method.
The experimental results were successfully correlated by the following empirical equation, including water depth H [cm], tower diameter T_d [cm], distance between origins of bubbles L [cm], number of bubbles N [-] and volume mean diameter of a bubble D₀ [cm] :
F_n/F₁=1.06 (H/D₀) ^0.216 (T_d/D₀) ^0.273 (L/D₀) ^-0.664 (N·W) ^-0.5
20≤H≤56.5, 6≤T_d≤36
where W is D₀ (2L).
The standard deviation of the 133 data obtained for this equation was found to be 9.0%.

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A CFM bed which consists of the combination of a fast fluidized bed (or an entrained bed) with a moving bed is proposed for the development of a new type of gas-solid contactor.
As the first step of R&D, the fundamental features of solid-particle flow such as particle holdup, particle velocity distributions and residence time of the particle were observed in a two-dimensional cold model by using glass beads as a typical fluidizing material under various solid/air ratios.
As a result, it was observed that there exists a minimum fast fluidization velocity to form a stable fast fluidized bed in the inner pipe. Particle holdup in the inner pipe decreased with increasing gas velocity in the inner pipe. The velocity distribution of the solid particle in both the inner and the annular parts were found to agree relatively well with those obtained by a simple theoretical analysis based on single-particle behavior. The residence time of the particle was in proportion to the height of the inner pipe, and the scale-up effect was obtained within the experimental conditions employed.

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Many problems must be worked out for practical use of the surfactant liquid membrane process. Among them, the following subjects are very important : (1) the selection of proper combination of extractant, surfactant and diluent as membrane liquid, and their concentrations ; and (2) the choice of species and concentrations of elution reagent in internal aqueous phase, and of adjuvant in external aqueous feed. solution. This paper deals with the recovery and concentration of chromium contained in aqueous sulfuric acid solution, and investigates the proper condition of the surfactant liquid membrane process and the possibility of recycle use of the organic phase as the membrane phase.
Tertiary amines such as tridodecyl or trioctyl amines diluted in kerosene, which are familiar as extractants for chromium, were found to form gel-like chromium complex in the presence of surfactant such as Span 80 or polyamine. The extracted chromium, therefore, was not transported to the internal aqueous phase through the organic phase. Chromium in the external aqueous phase was successfully transported and concentrated into the internal aqueous phase containing lithium hydroxide solution through the organic phase with 2-ethylhexyl alcohol and polyamine in kerosene. Further, it was found that recycle use of the organic phase did not affect the function of the surfactant liquid membrane.

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A reasonable method entitled is proposed. It has been obtained through comparing between the desighn methods of the heat exchanger and of the mass transfer device and is superior to the current method in the following points.
1) It is easy to understand because of its concise operation, in which the required number of transfer units calculated as a countercurrent device is considered to be the sum of the number of transfer units of each stage evaluated as a countercurrently equivalent one.
2) In approximating the equilibrium curve with straight sections, the effect of the mass transfer resistance in two phases is reasonably taken into account through use of tie lines.
3) Efficiencies capable of becoming greater than 100 % are not needed.

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The effect of corona wind on rates of heat transfer from horizontal, parallel cylinder banks was investigated.
Velocity distributions and maximum velocities of corona wind were measured under various conditions. The results could be explained well by a model based on the assumption that the wind blowing from the tip of a discharge electrode spreads out in the form of ellipses.
Average velocities of corona wind on each cylinder were derived by use of this model. Heat transfer coefficients of each cylinder were found to correlate well with these average velocities, and a non-dimensional correlating equation was proposed according to the manner usually employed in correlation of heat transfer coefficients of single cylinders in uniform flow.

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For a passive system of solar thermal energy storage, in which a plane layer of a semitransparent PCM (phase change material) is directly heated and melted by the sun, the effect of the optical thickness of the PCM on the temperature distribution and the efficiency of thermal energy storage was investigated. Paraffin wax was used as the PCM and a black dye was added to it to vary its absorption coefficient. Samples composed of the PCM layer and an insulating layer with adiabatic rear side were tested using a solar simulator with constant incident radiation. A theoretical analysis was carried out by applying the concept of overall specific heat.
The numerical results agreed fairly well with the experimental results within the range of the present experimental conditions and so this theoretical analysis proved to be valid. It became clear that the optical thickness of the PCM has a strong influence on the temperature distribution and the efficiency of thermal energy storage. It was found that a PCM with small optical thickness has greater efficiency of thermal energy storage because of inner (back) melting.

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Liquid-gas interfacial areas in a mobile bed contactor were investigated by using a chemical absorption method.
An empirical correlation equation covering a wide range of process variables was obtained as a function of gas and liquid holdups.
The effective interfacial area per unit expanded bed volume increases with increasing gas and liquid velocities to a maximum point and decreases beyond this point, while the effective interfacial area per unit liquid volume in the bed increases with increasing gas velocity, but the effect of the liquid velocity is small. When the gas and liquid velocities are 2.0-3.0 m/s and 0.01-0.03 m/s respectively, the effective interfacial area per unit expanded bed volume has a maximum point at a gas holdup of 0.6.

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The particle temperature of burning pulverized coal was measured by using a newly developed two-color pyrometer. It was found that the particle temperature exceeded the surrounding gas temperature by more than 900°C under some conditions. The particle temperature increased in proportion to the oxygen concentration of the surrounding gas. The temperature of large particles was 200-600°C higher than that of small particles. Furthermore, good agreement could be obtained between measured particle temperature and predicted temperature calculated from the measured reaction rate data assuming steady state. These results suggest that one must take the particle temperature into account in evaluating the combustion rate of pulverized coal, which has been related only with the surrounding gas temperature or wall temperature so far.

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To improve the collection efficiency of the “volume heat trap” type solar collector, making the working fluid layer a multilayer or a multipass was tried, using a transparent partitioning plate. The effects of flow mode and thermal resistance of the partitioning plate on collection characteristics in these collectors were studied.
The temperature distribution and the collection efficiency were measured for collectors with different partitioning plates under various flow modes. A theoretical analysis, taking natural convection into consideration, was performed and the calculated results were compared with the experimental data.
It was clear that the temperature distribution and the collection efficiency of the collector with partitioning plate depended greatly upon the flow mode and the thermal resistance of the partitioning plate. It was also found that, in the collector with partitioning plate of high thermal resistance, the collection efficiency of a multipass collector was greater than that of a multilayer collector.

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Electroosmotic dewatering of compressible sludge at constant voltage was studied theoretically and a basic equation for the estimation of the dewatering process is presented. The variations of water content and electric potential difference distributions in the sludge bed, dewatered volume, electric current passing through the sludge bed and height of sludge bed with dewatering time can be numerically analyzed by the basic equation. Their calculated results are compared with the experimental results obtained by using gelatinous bentonite sludge, and it was confirmed that the basic equation is usable for the estimation of electroosmotic dewatering at constant voltage.
An equation for average water content in the sludge bed was also derived theoretically. Based on the theoretical equation, an empirical equation for the average water content is obtained by using the final dewatered volume and the final height of the sludge bed. It is shown that the average water content in the dewatering process can be approximately calculated by the empirical equation.

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Flow transition from bubble flow to recirculating flow in a bubble column was experimentally studied. For a tap water-compressed air system, it was found that the hysteresis of the mean gas holdup against the increase and decrease of gas flow rate was closely dependent on the changing velocity of gas flow rate. It was also found that continuous operation at high gas flow rate usually makes the coalescence of bubbles easy, and that continuous operation at low gas flow rate tends to promote anti-coalescence. Considering the experimental results for a tap water-compressed air system together with the results for an ion exchanged water-compressed air system, a tap water-N₂ gas system and an ion exchanged water-N₂ gas system, the following results were obtained. 1. Tap water has a rather anti-coalescence effect compared with ion exchanged water. 2. Mist in the compressed air weakens the anti-coalescence effect when it is mixed in liquid. 3. The hysteresis of the mean gas holdup against the increase and decrease of gas flow rate is a result of the anti-coalescence effect of the liquid and the weakening effect of the impurities in the gas phase against the anti-coalescence effect.

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Ultrafine particles of nickel and molybdenum were prepared by hydrogenation of metal chloride in the gas phase. The effects of operation conditions such as reaction temperature and concentration of metal chloride on the particle size were investigated. Particles were characterized by means of transmission electron microscopy, X-ray diffraction and BET surface area.
The size of nickel particles decreased with increasing temperature in the range of 1050-1250K but increased with increasing temperature above 1250K. Near the melting point, the particle size obeyed the agglomeration theory which assumes that each particle fused immediately after mutual collision by Brownian motion.
The fusion of particles was possible even at relatively low temperatures when the particles were small. Particle growth by fusion was enhanced if metal monomer could deposit near the neck of agglomerated particles. After the disappearance of metal chloride, however, the rate of particle growth became very slow. Nickel chloride was consumed within 0.3 second under the present conditions.
Particle size was decreased by an increase in the rate of hydrogenation reaction.

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A binary mixture of hydrocarbons was separated by the batchwise liquid membrane permeation technique. Benzene-n-hexane was selected as a hydrocarbon feed mixture together with iso-octane as a solvent and an aqueous solution of saponin and glycerine as the membrane phase. With the assumption that the total rate of mass transfer for the permeable component consists of the rate of permeation, the rate of membrane breakage and the rate of mechanical entrainment, the contributions of these individual rates on the total rate were calculated. Membrane breakage had no influence practically on the more permeable benzene, but some detrimental effect on the less permeable hexane, where it caused a definite drop in membrane selectivity. After a relatively long period of contact, when the benzene content in the extract phase became higher, entrainment affected seriously the rate of benzene transfer. The overall permeabilities were 3-7 g/ (m²·min) for benzene and 0.2-0.5 g/ (m²·min) for hexane. The maximum membrane selectivity was about 45.

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Selective withdrawal from two-layer stratified fluids by a vertical pipe was studied experimentally. Experiments were performed under the conditions of upward withdrawal and downward withdrawal. Assuming the sink exerts force on the interface of two layers, the relationship between suction limit distance and densimetric Froude number was obtained. Suction limit distance for the lower-layer fluid under the condition of upward withdrawal and that for upper-layer fluid under the condition of downward withdrawal were both in good agreement with calculation.
It was found that the withdrawal ratio defined by the ratio of discharge from lower-layer fluid to total discharge varied linearly with the level of the interface. On the basis of sink flow between two parallel plates, the withdrawal ratio was studied hydrodynamically.

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Liquid-liquid equilibria for acetic acid-water-binary solvent systems were investigated at 25°C. The solvents used were 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and butyl acetate.
When the molar ratio of butyl acetate in the binary solvents was equal to that of alcohol, the distribution ratio of acetic acid defined by the molar fraction at infinite dilution had a maximum value and increased in the range of 5.0-5.4 in the order of 1-pentanol > 1-hexanol > 1-heptanol > 1-butanol.
When the mixing ratio of butyl acetate in the binary solvent increased, the selectivity between the water and the binary solvent increased. Selectivity increased with the alcohol carbon number.

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In the previous paper, it was demonstrated that the reaction could be divided into three regions, and the modified double shrinking core model, the double shrinking core model and the shrinking core model were applied to regions I, II and III respectively. However, the influence of different conditions on coal particle size change is not fully understood.
In the present paper, the influence of reaction temperature on changes in residue weight, particle size and density was examined, using Taiheiyo coal screened to 16/20 mesh as the starting materials. It was found that the effect of reaction temperature on coal particle change is very great in region I. Moreover, by assuming initial particle size using the double shrinking core model, the relation between reaction temperature and particle size change was clarified.

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The emission characteristics of char NO at combustion temperatures of 1073 to 1173K were experimentally investigated in a differential packed-bed reactor to eliminate the gas-phase reduction of the NO produced. In this study, Taiheiyo (non-caking bituminous) and Taisei (anthracite) coal-chars, and activated sludge-char for comparison, were employed. The ratio of fixed carbon to volatile matter of the original coals was between 0.1 and 4.2. The chars were preliminarily prepared at a devolatilization temperature about 100K higher than the combustion temperatures so that the effect of volatile matter on NO formation could be minimized.
The following results were obtained within the range of experimental conditions employed.
1) The fractional conversion of char N into NO (η_NO) during the combustion depended on the coal rank ; η_NO of Taisei chars was about 0.8, that of Taiheiyo chars was in the range of 0.3 to 0.6, and that of activated sludge-char was about 0.1. The η_NO gradually decreased with increasing particle diameter.
2) The η_NO obtained at a constant burning condition was found to increase with the initial mass ratio of char C to char N.

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Transient heat transfer characteristics of a typical heat pipe for which the thermal loading was variable with time were investigated experimentally by using an automatic measuring system. Significant behaviour of step, frequency and pulse responses of surface temperature and heat transferred in particular was observed.

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A nonionic temperature-sensitive water-absorbing hydrogel PVMEG (polyvinyl-methylether gel), which swells and shrinks reversibly in response to a small temperature change, was applied to sludge dewatering as a water-absorbing medium. The water-absorbing rate of the gel varied with the properties and solid concentration of the sludge. All the sludges tested were dewatered quite well by repeated use of the gel.

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Effects of moisture content on mechanical properties (Young's modulus, yield stress, tensile strength) of drying shrinkage materials (Kibushi, Haido and mixed clay, to which 10wt % of glass beads are added) were studied by measuring the stress-strain curves experimentally. It was found that these properties strongly affect the moisture content. Liquid transport properties (Permeability and osmotic suction pressure) were measured and a strong dependence was found. When glass beads are added to the Kibushi, Young's modulus and yield stress decrease and permeability increases in spite of the same tensile strength and osmotic suction pressure.

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The control scheme recently proposed by the authors for diffusion processes has been extended so as to be usable for systems with unknown parameters. The extended Kalman filter algorithm was used for simultaneous estimation of parameters and state variables. The performance of estimator and controller was tested in real time in an experimental heat conduction process. The results show that the control scheme is robust and performs well even with few sensors.

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To make a closed-circuit granulation system by a single horizontal rotating conical vessel having the functions of granulation and classification small in scale and simple in operation, a new equipment item, the rotary lifter, was developed in the present work for refeeding small ungranulated particles, which were discharged from the narrow end of the vessel. Large spherical granules as final product were discharged from the wide end of the vessel.
Under various circulating load ratios, closed-circuit granulation of calcium carbonate powder with water was carried out by such a horizontal rotating conical granulator with a rotary lifter. It was experimentally confirmed that more spherical and more uniform size products were obtained in the closed-circuit granulation than the total products in open-circuit granulation by the granulator.

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