KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 15 , Issue 2
Showing 1-38 articles out of 38 articles from the selected issue
  • Tohru Sema, Mikio Sato
    1989 Volume 15 Issue 2 Pages 195-201
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Pulverized coal combustion is the main combustion technology for coal utilization at present, and in the future, coal is expected to play an even greater role as a fuel because of improvements in environmental protection technology, coal liquefaction and clean coal technology. SRC-I/heavy oil slurry fuel (SOM) is produced by mixing solvent refined coal (SRC-I) and heavy oil.
    SOM is a convenient fuel for use in existing combustion facilities because it is a liquid fuel.
    This, report describes the combustion characteristics of SOM using a newly designed burner in our test furnace.
    Main results are as follows.
    (1) It is possible to burn SOM with minor improvements in fuel feed equipment and burner.
    (2) For good combustibility of SOM, excess O2 concentration in flue gas Should be over 1.5 %.
    (3) SOM should be preheated to over 373K to achieve desired fuel spray characteristics.
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  • Masanori Aoki, Kazunori Kawaguchi, Kazuhiro Nagaoka
    1989 Volume 15 Issue 2 Pages 202-207
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A vortex-type settling tank is developed as a replacement of the rectangular grit separator traditionally in use in sewerage and other systems. The settling tank performance of the new separator is discussed in this paper.
    The vortex-type settling tank is so designed that sewage containing grit flows tangentially into a circular water tank. While the sewage is whirling in the water tank, grit contained in it settles. Water free of grit drains from the outlet located in the side wall. Since this tank has a cone-shaped bottom, grit tends to settle at the center of its bottom.
    The vortex-type settling tank is compared in performance with the conventional rectangular one..It is found that this settling tank exceeds its counterpart in grit separation and collection performance. The law of similarity concerning grit separation performance is defermined and the equation by which the performance is predicted is thus obtained.
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  • Yorishige Matsuba, Teruo Takahashi, Yoshiro Kitamura
    1989 Volume 15 Issue 2 Pages 208-213
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Liquid-liquid equilibria data for a system of n-heptane, acetonitrile (10 wt % water) and fatty acids (oleic, linoleic, linolenic) were experimentally investigated. A correlation method was proposed by taking account of association of fatty acids in each phase. In this correlation, the concentration of the i-component fatty acid in the acetonitrile phase, yi, is related to the concentration of solute in the pure i-component system,
    y°i, at the same concentration of total solutes in the n-heptane phase, χ, and the solvent-free mole fraction of the i-component in the n-heptane phase, Xi, as follows.
    yi=y°i Xi
    The experimental data were well correlated by this equation. In addition, y°i is given as a function of χ for each component mentioned above.
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  • Akira Hirata, Yukihisa Hosaka
    1989 Volume 15 Issue 2 Pages 214-218
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Biological treatment of actual drum-washed wastewater was carried out with a pilot-scale rotating biological contactor (RBC) for a long time. The drums had been used as containers for various oils and chemicals. The disk of the RBC was 1.2 m in diameter and 2.5 m in length. The characteristics of biological treatment were evaluated. It is concluded that :
    (1) This wastewater consisted of various pollutants and hard-biodegradable substance, and these concentrations were very changeable ; nevertheless it was confirmed that this wastewater could be treated sufficiently and continuously by RBC. (2) It was possible to apply the method of characteristics evaluation of biological treatment in the three-phase fluidized bed system to that in the RBC. The substrate removal in biological treatment of the drum-washed wastewater was treated as a first-order reaction. (3) The characteristics value was affected by temperature. The apparent activation energy was 4.7 × 104J·mol-1. (4) The basic data for the design of a full-scale RBC were obtained.
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  • Ryohei Yamazaki, Ryokichi Sugioka, Osamu Ando, Genji Jimbo
    1989 Volume 15 Issue 2 Pages 219-225
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    From the measurement of the bed pressure drop and gas velocity in inclined fluidized beds, it was found that two minimum fluidization velocities, i.e., initial and steady minimum fluidization velocities, could be defined.
    An analytical and semi-empirical equation for estimating the minimum fluidization velocity and the pressure drop was obtained by considering force balance in a powder bed.
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  • Kazuhiro Murai, Yohsuke Kawashima, Shigeyasu Nakanishi
    1989 Volume 15 Issue 2 Pages 226-230
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A practical calculation method for the capacity of varying-pressure accumulators is presented. We introduced previously two functions of pressure for calculation of the amount of self-evaporation. These functions are represented in two diagrams respectively in order to make practical use of the new method. One of the great merits of this graphical method is that the effect of the initial steam space on the capacity of the varying-pressure accumulator can be calculated without need of any additional correction operation.
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  • Masaaki Nakamura, Katsumi Ito, Shigeki Toyama
    1989 Volume 15 Issue 2 Pages 231-237
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The continuous stirred-tank reactor (CSTR) has many advantages, such as large heat transfer coefficient and good controllability of temperature, but it has poor efficiency for reaction. To enhance the efficiency of the vertical CSTR, attachment of many partition plates in the reactor is very effective, especially for gas-liquid or solid-liquid flow. In the vertical multistage CSTR, back flow of liquid through each partition plate affects reactor performance.
    In this study, the back flow ratio of liquid was measured with varying geometrical and operating conditions, such as impeller, free-area fraction and thickness of a partition plate, tank diameter, superficial liquid velocity and stirring speed. The lowest values were observed when a 4-blade turbine and a partition plate with opening located at the center of the tank were used. The back flow ratio increased with increasing stirring speed or free area fraction, and decreased with increasing superficial liquid velocity. In geometrically similar equipment, the back flow ratios were the same at the same mean residence time and mixing power per unit volume.
    Finally, the procedure for design of the multistage CSTR with partition plates is discussed according to results obtained here.
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  • Hitoshi Takase, Masunori Sugimoto
    1989 Volume 15 Issue 2 Pages 238-245
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To investigate the drainage of a bed which was packed with coal agglomerates obtained by oil agglomeration, dewatering experiments were carried out by using gravitational and air blow drainage under various conditions. The drainage characteristics of the bed are discussed on the basis of agglomerate size and other factors concerned with drainage phenomena.
    In gravitational drainage, the time required to reach equilibrium was dependent on the size of agglomerates and it increased rapidly at less than a certain agglomerate size. The moisture content of the bed decreased with increasing size of the agglomerates. The values of the minimum moisture content after gravitational drainage and after air blow drainage were about 15 % and 10 % respectively. It could be estimated on the basis of a few assumptions that the weight ratio of the water in each agglomerate to the total water in the bed increased with decreasing size of the agglomerates.
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  • Eiichi Kunugita, Sang-Rok Lee, Hiroko Harai
    1989 Volume 15 Issue 2 Pages 246-250
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A method for determining the safe operating region for liquid-phase oxidation of hydrocarbons in perfectly mixed flow tank reactors is proposed. This region containing the steady state can be constructed by the state variables of a reactor in state space. All trajectories of the representative points pass into the region at the boundary surface.
    Since the representative points in the region never drift out, it is safe to keep the reactor in the region for steady-state operation and to choose trajectories that cannot drift into an explosive region before approaching the safe operating region during start-up of the reactor.
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  • Ikuho Yamada, Hideki Mori, Yoshihito Kato, Tsutomu Aragaki, Setsuro Hi ...
    1989 Volume 15 Issue 2 Pages 251-257
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The minimum reflux problem for Petlyuk's distillation process, which utilises two distillation columns with reversible flows, is solved by use of the concept of a hypothetical pinch plate. The concept was previously applied to solving the minimum reflux problems of both conventional and complex distillation processes. To construct the process model under minimum reflux condition, the following assumptions are made; i) pinch points are located in the sections where infinite plates are assigned, but not adjacent to feed and side-cut plates, and ii) a finite number of plates is assigned around the feed and side-cut plates, and the hypothetical pinch plates are located at both ends of the finite number of plates.
    The proposed algorithm basically consists of the following three major calculation loops :
    1) Correct the liquid compositions of the hypothetical pinch plates based on assumed values of the component molar flow rates of the reversible flows entering each column using the normalized θ-method.
    2) Correct the component molar flow rates required for the calculation in step 1) by successive substitution.
    3) Determine two controlling parameters for the vapor and liquid reversible flows by optimization procedure using the Box complex method and golden section algorithm.
    The usefulness of the proposed method and the location of the pinch point in each section of the column are illustrated by numerical examples.
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  • Shigeyuki Tomita, Hisashi Yabusaki, Eiji O'shima
    1989 Volume 15 Issue 2 Pages 258-268
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Although utilizing heuristic knowledge of various types effectively is indispensable to operating a chemical plant safely, very few methodologies for utilizing it on a computer-based system have been reported. The importance of this matter is increasing especially in the case of fault diagnosis. The work presented here addresses the following two issues : classification and encapsulation of heuristic knowledge of human operators which must be utilized in diagnosing failures of chemical plants, and establishment of a framework for developing a fault diagnostic system which mimics the manner of human operators.
    When the plant control system has given an alarm, the operators first try to narrow down their focus to a bounded section where the fault may exist by testing if none of various relations inhering in the plant is violated. Then, they try to find the possible cause of the fault by simulating qualitatively the phenomenon that is occurring in the section. A computer-based system has been developed together with a knowledge base by following this procedure. The system has also been developed in open-ended fashion by using multi-language paradigm. The system is easy for human operators to accept, because the diagnostic algorithm is similar in manner to their own.
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  • Takashi Hibiki, Manabu Yamaguchi, Takashi Katayama
    1989 Volume 15 Issue 2 Pages 269-275
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The stability of a cylindrical jet of an incompressible, inviscid, dielectric liquid in a nonunifrom electric field was studied theoretically. The field is formed by a configuration of an electrified nozzle arranged vertically above a flat earthed electrode. Wave number and growth rate for the surface wave of the jet in the electric field were derived from the Lagrangian equation of motion for the jet. Perturbation analysis of the wave was used to formulate the equation.
    The effect of the electric field on the dynamic characteristics of the jet was investigated by numerical analysis, and it was confirmed that the wave number and maximum growth rate of the surface wave increased and the size of the drop formed decreased with applied voltage.
    The experimental drop diameter for the system of water jet in air in the nonuniform electric field agreed well with the calculated one.
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  • Yoshitaka Nishino, Toshio Sawa, Katsuya Ebara, Hisao Itoh
    1989 Volume 15 Issue 2 Pages 276-283
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The reactions of nickel with iron hydroxides and oxides are investigated under simulated operating conditions of boiling water reactors (BWRs). These chemicals are commonly found in BWR cooling water due to material corrosion. The thermodynamic calculations suggest that nickel's reaction with any of the iron hydroxides and oxides will form nickel ferrite at temperatures below 573K. This experiment indicates that only three kinds of iron hydroxides-γ-FeOOH and two types of amorphous hydroxides-react with nickel hydroxide to form nickel ferrite. These three iron hydroxides are transformed into α-Fe2O3 in the high-temperature water due to dehydration. At the same time, nickel ions combine with particles of iron compounds to form nickel ferrite. The nickel ferrite produced by the reaction of nickel with the crystalline γ-FeOOH forms the largest crystallite with the smallest specific surface area. The dehydration rates of the three iron hydroxides that form nickel ferrite are accounted for by Avrami's equation. According to this analysis, γ-FeOOH had the highest apparent activation energy of dehydration (231 kJ/mol).
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  • Masataka Shimizu, So Takeoka
    1989 Volume 15 Issue 2 Pages 284-291
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    To obtain basic data for methanol onboard reformer design, a kinetic study for the decomposition of methanol over Raney nickel alloy catalyst was carried out in a flow reactor at atmospheric pressure. The initial methanol decomposition rate, ri at a methanol partial pressure, PMeOH, in the range of 2070kPa, was
    ri= αPMeOH/ (1+βPMeOH) 2
    where α and β are constants.
    It was suggested that methanol adsorbed on the catalyst in an undissociative mode. The rate expression for methanol decomposition was assumed on the basis of the postulated mechanism, which involves the undissociative adsorption of methanol as the first step and hydrogen withdrawal from adsorbed methoxy radical as the rate-determining step.
    Kinetic analysis was performed for the reaction data obtained in the temperature range of 556628K by using integral reactor. The results calculated by the assumed rate expression agreed well with the experimental data. For the dehydration of methanol, occurring in parallel with the decomposition, the rate was found to be of first order with respect to the partial pressure of methanol.
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  • Masahiro Ohga, Michiko Izaki, Hisayoshi Matsuyama
    1989 Volume 15 Issue 2 Pages 292-298
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A method has been developed for judging the existence of the quaternary azeotrope in a quaternary system at constant pressure by use of a topological condition to be satisfied by the indices of pure materials and azeotropes and a thermodynamic condition to be satisfied by their bubble-point temperatures. Given the boiling temperatures of the pure materials and the compositions and boiling temperatures of binary and ternary azeotropes in the quaternary system, the method can sharply reduce the number of experiments because it requires only one experimental run for each ternary azeotrope. The method is applied to the acetone-methylacetatemethanol-hexane system in order to demonstrate the procedure of judgement.
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  • Takuo Imasaka, Nobuhiko Kanekuni, Naohito Wajima, Shigeru Yoshino
    1989 Volume 15 Issue 2 Pages 299-305
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Using a ceramic membrane, cross-flow filtration was experimentally studied for particle suspensions of uniform diameter. A modified standard filtration model was applied to calculate a time-decline curve of permeate flux. A comparison of calculated results with experimental ones demonstrated that this model could effectively predict the flux-decline curve against the various membrane characteristics and operating conditions.
    A so-called “dynamically formed self-rejective membrane” behavior was observed in the cake layer formed on the membrane surface. It was also noted that not only the compaction of cake layer and/or plugging of particles into the membrane pores but also the difference of cake layer thickness caused by the magnitude of the transmembrane pressure difference were responsible for the presence of critical permeate flux.
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  • Takuo Imasaka, Nobuhiko Kanekuni, Naohito Wajima, Shigeru Yoshino
    1989 Volume 15 Issue 2 Pages 306-312
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The authors proposed a gas-liquid two-phase cross-flow filtration system which provided a turbulence-promoting effect of gas-liquid mixtures to suppress cake formation on the membrane surface. With a view to clarifying the characteristics of such system, two-phase cross-flow filtration of submicron particle suspensions of uniform diameter was experimentally studied using a tubular ceramic membrane.
    Based on observations that confirmed the presence of the maximums of permeate flux and natural circulating liquid flow rate against a different feed-gas flow rate, the superficial linear velocity of two-phase mixture was considered dominant for the permeate flux. The measured value of liquid flow rate was in good agreement with the value predicted by using the reported equations of two-phase frictional pressure drop and void fraction. A modified standard filtration model taking the two-phase lift velocity into consideration was extended as in the case of liquid single-phase flow. The predicted value of the permeate flux in two-phase cross-flow filtration did not satisfactorily agree with the measured value. The results suggested that it was not practical to evaluate the two-phase viscosity by quality alone. Further investigation is required for valid evaluation of the two-phase lift velocity including the influence of flow patterns.
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  • Ning-He Wang, Shigeki Takishima, Hirokatsu Masuoka
    1989 Volume 15 Issue 2 Pages 313-321
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Solubilities of benzene in PIB at 313.2, 333.2 and 353.2 K and those of cyclohexane in PIB at 313.2 and 333.2 K were measured by the piezoelectric-quartz sorption method. The experimental data were correlated by the modified dual-sorption model, which was expressed by the overall relation of the UNIQUAC+FV equation and the Langmuir equation. Then the effect of adsorption on the experimental data was quantitatively studied and the contribution of adsorption was eliminated from the data. The corrected solubilities agreed with the literature.
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  • Yasutoshi Shimizu, Minoru Rokudai, Sachio Tohya, Eisuke Kayawake, Tets ...
    1989 Volume 15 Issue 2 Pages 322-328
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    For the purpose of selecting or developing appropriate inorganic membranes for methane-fermentation membrane bioreactors, the relationship between the pore size of a membrane and the filtration characteristics for methanogenic waste was studied. Tubular alumina membranes having pore size of 0.01μm1.6μm were used for the experiments. Filtation tests showed that an optimum pore size giving maximum permeation flux through the membrane existed. The permeation flux was restricted by the hydraulic resistance of the particle layer formed on the membrane surface through filtation. It was also affected by the resistance of a plugging layer formed in the membrane interior when pore size was over 0.4 μm and by the resistance of the membrane when pore size was under 0.1 μm. Therefore, the alumina membrane of 0.1 μm pore size gave the highest J value. It was also shown that plugging occurred in the starting period of the filtration when the membrane pore size was bigger than particle size. This was confirmed by measurement of particle rejection.
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  • Bae Sung-Keun, Takashi Akehata, Hajime Unno
    1989 Volume 15 Issue 2 Pages 329-335
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Pyrolysis of high-density polyethylene (HDPE) pellets as a model of plastic wastes was studied at a furnace temperature of 700°C to 800°C and under nitrogen atmosphere in a silica sands fluidized bed of 5.5cm inner diameter. The operating conditions such as the reaction bed temperature, feed rate of HDPE, and superficial velocity of fluidizing gas were varied.
    The pyrolysis reaction was essentially complete in this range of reaction temperature. The gas produced became of lower molecular weight at higher reaction temperatures and at longer residence time. As the feed rate of HDPE increased, the product gas per unit weight of HDPE became small in volume, but of higher calorific value.
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  • Osamu Hashimoto, Takeo Haruta, Shigekatsu Mori, Setsurou Hiraoka, Ikuh ...
    1989 Volume 15 Issue 2 Pages 336-342
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A simulation model is developed to describe the turbulent fluidized-bed catalytic reactor. The features of the proposed model are as follows :
    1) A mean void fraction ε is considered instead of bubbles and its value is affected by the operating condition.
    2) A multistage perfect-mixing cell model with up-and-down flows of particles is considered to describe the gas and solid mixing in the bed.
    It was confirmed that the calculated results from this model can explain the observed data obtained from a high-pressure bench-scale methanol synthesis reactor. Furthermore, resulting the sensitivity analysis for model parameters, it is concluded that the temperature profile which controls the yield of methanol is most seriously affected by the value of mean void fraction ε. Consequently, the accurate estimation of ε is most important to establish the simulation model of the turbulent fluidized-bed catalytic reactor.
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  • Masahiro Hasegawa, Torajiro Honma, Yoshiteru Kanda
    1989 Volume 15 Issue 2 Pages 343-348
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Vibration ball milling was carried out using three mills of cylindrical, capsule and spherical type respectively with the same internal volume, and the specific surface area of the product was examined. An empirical equation of grinding rate applicable in the region of short grinding time (t <1800s) was proposed to investigate the effect of mill shape on grinding rate. It was found that the specific surface area was apparently influenced by the mill shape. Under the same operating conditions the specific surface areas of product by capsule and spherical mills were greater than that by the conventional cylindrical mill. The grinding rate by the spherical mill was found to be about 30% greater than that by the clindrical mill in terms of the empirical equation proposed.
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  • Hiroshi Ooi, Mototake Yano, Yoshiharu Tsugou, Yoshio Harano
    1989 Volume 15 Issue 2 Pages 349-356
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Ni/SiO2 catalysts were prepared by chemical fume thermal deposition. This preparation proceeded as follows. Nickel-salt/methanol solution was sprayed into a tubular reactor with vaporized SiCl4 and air, and then the mixture was immediately pyrolyzed in a reactor whose temperature was controlled at 1573 K at the hottest point.
    The apparent diameter of the catalyst produced was estimated by the BET method, and the diameter of NiO, dNiO, x, was measured by XRD. The relationship between dNiO, x and the relative viscosity of sprayed solution, η, was represented by the following equation under the present experimental conditions.
    dNiO, x=k0.45) n
    where n and k are different for each case; n=1.48, k=19 nm for the [Ni (NO3) 2 /CH3OH+air+SiCl4] system, n=1.48, k=32 nm for the [NiCl2 /CH3 OH + air + SiCl4] system, n=0.64, and k=110 nm both for the [Ni (NO3) 2 CH3OH+air] system and the [NiCl2/ CH3OH+air] system.
    The apparent growth rate of the catalyst, γap, is proportional to the molar fraction of Ni salt, χ.
    γap=kapχ
    The reactivity of the catalyst was examined by the methanation of carbon mono-xide as a model reaction. The results show that the activity (TOF) was one or two magnitudes higher than those of conventionally prepared impregnated catalysts.
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  • Yoshitake Nishino, Toshio Sawa, Hisao Itoh
    1989 Volume 15 Issue 2 Pages 357-363
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The reaction of γ-FeOOH, which is present in the condensate water of power plants, with nickel hydroxide in high-temperature water was investigated. When γ- FeOOH powder adhering to nickel hydroxide is heated, NiFe2O4 is formed simultaneously with α-Fe2O3 by dehydration of γ-FeOOH. The rate of the dehydration reaction of γ-FeOOH can be described by Avrami's equation. Its activation energy in water is about 15 % less than that in nitrogen gas. After the formation of NiFe2O4, the diameter of the particles is larger than that before the reaction. The specific surface area of particles decreases with reaction time. The dissolved oxygen concentration in water has no effect on the reaction of γ-FeOOH with nickel hydroxide. When pH is lower than 5, dissolution of the reacted particles is accelerated and the fraction of NiFe2O4 in the particles increases. The variation of NiFe2O4 fraction with time was examined with the equation of the product of nickel permeation fraction inside the particles and the dehydration rate equation of γ-FeOOH (Avrami's equation).
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  • Tsuneyuki Sato, Hitoshi Kuga, Toshikuni Yonemoto, Teiriki Tadaki
    1989 Volume 15 Issue 2 Pages 364-371
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Chemical absorption of H2S by aqueous solutions of NaOH in a wetted-wall column was simulated, using a theoretical model based on transport equations for the gas and the liquid phases. Two-step instantaneous reversible reactions and ionic migration of charged molecules in the liquid phase were taken into account in the model formulation. The equations were solved by using a finite-difference technique.
    Theoretical absorption rates of H2S obtained for pure and mixed gas flow conditions were compared with experimental ones. Agreement between theory and experiment was excellent.
    The distribution of S2- in the liquid film was also quantified, and the effect of the gas-phase mass transfer resistance on the absorption rates was discussed.
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  • Masanobu Hasatani, Hitoki Matsuda, Katsuhisa Kumazawa
    1989 Volume 15 Issue 2 Pages 372-380
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    As a step in the research on a high-temperature desulfurization cycle of low-calorie gasified gas by means of iron oxide sorption, a fundamental study on the regeneration of iron sulfide with dry air was carried out by use of a packed-bed reactor.
    The iron sulfide packed in the bed could be converted to fresh iron oxide without any drop in the reactivity or the capacity as a sorbent, and the reaction product gas, sulfur dioxide, was released from the reactor at the stoichiometric concentration. It was recognized that the reaction time was approximately inversely proportional to the mass flow rate of air at the bed inlet. By decreasing the mass flow rate of air at the bed inlet, the temperature rise of the bed could be suppressed as low as possible, regardless of the large quantity of exothermic heat of oxidization of iron sulfide.
    The experimental trends mentioned above could be explained fairly well by the theoretical model derived under various assumptions.
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  • Katsuhiko Fujinawa, Makoto Akiyama, Atsushi Shono, Nobuyuki Imaishi, M ...
    1989 Volume 15 Issue 2 Pages 381-387
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The applicability of supported liquid membrane (SLM) to a hydrometallurgical process of gallium and indium is discussed. The conventional process has three extraction stages. Here two of these stages, namely Ga separation stage with isopropyl ether (IPE) as the extractant and In separation stage with tri-n-butyl phosphate (TBP) are examined.
    Under the experimental conditions, the permeation rate of Ga in the IPE system and that of In in the TBP system are revealed to be limited by the mass transfer in the feed solution flow channel. The necessary membrane lengths to recover 99% of Ga and In from feed solution are calculated to be about 10m in each system. It is shown that the separability of Ga or In from other metals in SLM systems is lower than that in the conventional equilibrium separation.
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  • Yasuhide Nishi
    1989 Volume 15 Issue 2 Pages 388-394
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A pipeline network consists of a number of source points, consumption points and branches connecting between these points. Fluid pressure of the source and allowable pressure drop are specified. It is assumed that both cost and pressure drop along the pipeline are proportional to pipe length and are functions of flow rate and pipe diameter.
    This paper describes an algorithm to determine the pipeline route and diameter that minimizes pipeline cost. The algorithm consists of step determining a starting solution near the optimal solution and step adjusting the starting solution. According to the algorithm, it is not necessary to share consumption points among multiple source points. The algorithm can treat a considerably large-scale network by use of a personal computer. An example is also presented.
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  • BohYoh Shibata, Hisayoshi Matsuyama
    1989 Volume 15 Issue 2 Pages 395-402
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    A method of evaluating the accuracy of fault diagnosis based on a signed directed graph is described, utilizing the greatest sets of candidates. An acetic acid manufacturing process is taken as an example to show the usefulness of this method and to compare it with the method of evaluation of accuracy utilizing the envelope set of candidates. This can be applied to the problem of optimal sensor location and the decisionmaking system for emergencies of a chemical plant.
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  • Tadaatsu Ido, Motohisa Saiki, Shigeo Goto
    1989 Volume 15 Issue 2 Pages 403-410
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The effective treatment of polyethylene glycol as phase transfer catalyst for use in a continuous process was investigated. The third phase (referred to as middle phase) appeared between toluene containing polyethylene glycol (organic phase) and aqueous solution of potassium hydroxide (aqueous phase) by addition of methanol.
    No basicity of catalyst (polyethylene glycol with molecular weight 3000) was detected in the organic phase but was detected in the middle phase and most of the catalyst was present in the middle phase. Repeated use of the catalyst was undertaken by use of this phenomenon. The dehydrohalogenation of 2-bromooctane in organic phase by polyethylene glycol was investigated in a batch reactor containing aqueous phase. Only the organic phase containing reaction product was removed from the reactor after the reaction was completed. By adding fresh organic phase containing reactant, the reaction was started again. This procedure was repeated four times to check the amount of loss of catalyst in the repetitions. The results were in good agreement with those calculated without loss of the catalyst.
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  • Kazumasa Kobayashi, Tadashi Nishio, Hiroshi Yukawa
    1989 Volume 15 Issue 2 Pages 411-415
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Bacteria able to oxidize ferrous ion have been found in solutions collected at the Kosaka Smelter & Refinery of the Dowa Mining Co., Ltd., the Tuchihata Mine of the Tanaka Mining Co., Ltd. and the Ashio Dozan Kanko. The batch culture experiments with these iron-oxidizing bacteria were carried out to verify the constancy of bacteria yield to substrate concentration and to examine the dependence of bacteria yield on temperature. As for the batch culture of the bacteria, Lacey et al. analyze the variations of consumption of substrate (ferrous ion) and bacterial growth with the passage of time based on the anatogy with the Michaelis-Menten kinetics. It was confirmed that the experimentally obtained results of the consumption of substrate and bacterial growth with time coincided with the equations analyzed by Lacey et al. with the aid of the least square method. The values of the bacteria yield, Y, maximum specific growth rate, μm, and saturation constant, K, were obtained from the results in the temperature range of 15 to 40°C. Values of both Y and μm were maximal between 25 and 30°C. These observed values support the conventional theory that the optimal temperature lies between 27 and 30°C. The values proposed in this study are the basic data in applying those bacteria to the leaching of metal sulfide.
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  • Zongxue Quan, Katsuki Kusakabe, Shigeharu Morooka
    1989 Volume 15 Issue 2 Pages 416-418
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Electrolysis of Cu-EDTA solution was performed using a bipolar electrode cell with carbon cloth electrode. In this case, each anode-cathode pair was made of a sheet of woven carbon cloth which passed through a narrow slit in a partition plate and was attached to both surfaces of the partition plate. The cell was assembled with 11 bipolar units. The average current efficiency in the range of copper concentration 0.310 mol·m-3 was 50 % at a cell voltage of 22 V. The regulation of copper concentration in the effluent (i.e. 3 ppm) was attained when the solution pH was lower than 3. The average current efficency was 10 % at a cell voltage of 16.5 V for the solution of pH 3 and copper concentration 0.04 1 mol·m-3.
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  • Ryokichi Sugioka, Ryohei Yamazaki, Osamu Ando, Genji Jimbo
    1989 Volume 15 Issue 2 Pages 418-421
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The characteristics of slugs, such as slug size and slug rising velocity, were investigated by use of an inclined fluidized bed of relatively large height compared with its diameter.
    The ratio of the vertical slug diameter (width) to the horizontal diameter (height), slug rising velocity and so on were affected by the angle of the inclined bed and the gas velocity. An empirical equation of the relationship between the diameter ratio and the rising velocity was obtained.
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  • Katsuhiko Fujinawa, Hidenori Adachi, Nobuyuki Imaishi, Mitsunori Hozaw ...
    1989 Volume 15 Issue 2 Pages 421-424
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    It is shown experimentally that deterioration of supported liquid membrane of LIX64N for copper extraction is caused by at least two reasons. One, as has been pointed out by many authors, is wash-out of extractant (LIX64N) and the other noted for the first time, is contamination by some unknown substances dissolved from rubber and/or soft polyvinyl chloride into feed, stripping and membrane liquids.
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  • Yoshiro Kitamura, Hiroshi Tatano, Atsuhiko Takehara, Teruo Takahashi
    1989 Volume 15 Issue 2 Pages 425-427
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The effect of alcohols in water phase on the breakage time of oil-in-water emulsions made from diesel fuel and fuel oil (A) was experimentally investigated. The presence of monohydric alcohols such as methanol and ethanol destabilizes water-in-fuel emulsions prepared using Span 80, although these emulsions have much longer breakage time than water-in-kerosene emulsions. The surface excess of the surfactant (Span 80) at the fuel/aqueous ethanol solution interface was measured. The presence of ethanol reduces the surface excess for the two fuel/water systems, as likely as the kerosene/water system. Such behavior of the surface excess corresponds to the reduction of the breakage time by the alcohols.
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  • Shigeki Toyama, Hidetoshi Mori, Masanori Suzuki
    1989 Volume 15 Issue 2 Pages 428-431
    Published: March 10, 1989
    Released: February 12, 2010
    JOURNALS FREE ACCESS
    Fundamental properties of cross-flow moving-bed filters were experimentally investigated.
    In comparision with fixed-bed filters, collection efficiency decreased due to dust entraiment caused by the movement of filter media after reaching a critical inlet dust load.
    The additional pressure loss was proportional to the 1.3th power of the retained dust loading, which was similar to the result for the fixed bed. It was, however, experimentally found that the additional pressure loss was not dependent on filtration velocity. Pressure loss buildup was predicted by assuming uniform deposition of dust around the filter media.
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  • Osamu Miyatake, Hiroyuki Iwashita, Shuji Yamamoto
    1989 Volume 15 Issue 2 Pages 431-434
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    Rates of laminar heat transfer in axial fluid flow through triangular and square arrays of cylinders were investigated experimentally for the case of cylinders in contact with one another.
    The experiments were conducted by using ducts of the same cross sections formed by both arrays of contacting cylinders, and the boundary condition of uniform temperature at the cylinder wall was substantially achieved.
    Reasonable agreement was found between the logarithmic mean Nusselt numbers obtained from the experiments and those predicted by the authors' previous numerical solutions when a Sieder-Tate type of viscosity ratio correction was applied to account for the effect of variation in fluid viscosity.
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  • Koei Kawakami, Kanya Horiki, Akira Ogawa, Koichiro Kusunoki
    1989 Volume 15 Issue 2 Pages 435-437
    Published: March 10, 1989
    Released: October 21, 2009
    JOURNALS FREE ACCESS
    The dehydrogenation of methylcyclohexane was carried out in a differential fixed-bed reactor at 781 K and atmospheric pressure, and the deactivation rates of Pt-, PtRe-Al2O3 and the sulfided catalysts were compared. The presence of Re and presulfiding of the catalysts resulted in improved stability. Continuous addition of H2S at a concentration of 50 ppm in feed was effective for maintaining the activity with Pt during only the first few hours of operation, while it caused a marked decrease in the initial activity with PtRe. The experimental results were interpreted by the ensemble effect.
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