KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 22 , Issue 5
Showing 1-43 articles out of 43 articles from the selected issue
  • Iori Hashimoto
    1996 Volume 22 Issue 5 Pages 973-984
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Process Systems Engineering (PSE) has almost 35 years of history as a new discipline with the mission to establish theories and methods for the planning, design, management, and operation of process systems.
    In an attempt to grasp the historical perspective of PSE research, this report reviews the past activities of the JSPS Research Committee No. 143 on Process Systems Engineering since its foundation exactly 20 years ago--the period in which the committee has played a pivotal role in the PSE research in the country. The series of PSE International Symposiums which started in Kyoto in 1982, as well as some contributions presented at major conferences held in Europe and North America, are also analyzed.
    With the 21 st century already in the sight, the chemical industries of Japan currently face many difficult challenges. In order for PSE to be able to help solve those problems, further development including some new paradigms, is very much desired. This report touches upon such possibilities.
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  • Takeichiro Takamatsu, Masaru Nakaiwa, Toshinari Nakanishi
    1996 Volume 22 Issue 5 Pages 985-990
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The concept of a new distillation column which has no reboiler and no condenser, in which liquid and vapor reflux flows are generated by heat transfer between the enriching and stripping sections, is shown (abbreviated as HIDiC). Under some simplifying assumptions, a design method which is based on the famous but classic MaCabe-Thiele method is given, and a numerical example is shown for a benzene toluene system. The feasibility of this distillation without reboiler and condenser was made clear.
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  • Yoshitomo Hanakuma, Kazutoyo Nakaya, Takeshi Takeuchi, Takashi Sasaki, ...
    1996 Volume 22 Issue 5 Pages 991-995
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method of modeling for nonlinear process dynamics by chaotic time-series analysis has been developed. It involves the search of simular characteristic short-term dynamics of the past time-series data which is compared with the present short-term time-series data using the chaotic time-series analysis and the determination of future dynamics by the past simular short-term dynamics. It was applied to the bottom temperature control loop of a demethanizer distillution column in an ethylene plant to confirm the design philosophy. The actual result indicates that the proposed method in this study has the advantage of modeling for nonlinear process dynamics.
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  • Yoshitomo Hanakuma, Kazutoyo Nakaya, Takeshi Takeuchi, Takashi Sasaki, ...
    1996 Volume 22 Issue 5 Pages 996-1000
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method of modeling for nonlinear process dynamics using the discrete volterra series model has been developed. It involves the parameter estimation of a volterra series model by an adaptive digital filter method and calculation of several IAEs between process output and model output in sequentially combinating a volterra series structured order and input series order. The optimum structure of a volterra series model which has minimum IAE is determined by comparing with several IAEs. It was applied to the bottom temperature control loop of the demethanizer distillation column in an ethylene plant to confirm the design philosophy. The actual result indicates that the proposed method in this study has the advantage of modeling for nonlinear process dynamics.
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  • Yoshihiro Hashimoto, Takayuki Shiina, Akihiko Yoneya, Yoshitaka Togari
    1996 Volume 22 Issue 5 Pages 1001-1008
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In moving towards the production of high added value chemicals, changes in operating conditions become larger and more frequent and increases in the strength of nonlinear characteristics of the dynamics of the plant occur. In order to achieve good control, it is important to use nonlinear regulators. Linearizing control is a nonlinear control theory which can be easily understood and does not need heavy computation load for online control. However, linearizing control needs feedback of all state variables. In this paper, a structure of a set of nonlinear blackbox models is proposed. All of the state variables in the model can be expressed using inputs and outputs. The state feedback of the blackbox model can be realized using the combination of inputs and outputs. Therefore, the linearizing controller can be designed based on the blackbox model which approximates the nonlinearity of the plant. The blackbox model can express multi-steady states and changes in lag time. Simulation studies for an exothermic reactor show that the proposed black box model can approximate the nonlinear dynamics and the controller based on this model performs satisfactorily.
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  • Kazuhiro Takeda, Yoshifumi Tsuge, Hisayoshi Matsuyama
    1996 Volume 22 Issue 5 Pages 1009-1017
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It is essential to quantitatively estimate the performance of fault diagnosis. In particular, two quantitative performance criteria are very important : diagnostic reliability and diagnostic accuracy. Each criteria is defined for the design phase and the running phase, respectively. This paper addresses diagnostic reliability for the running phase and diagnostic reliability and accuracy for the design phase.
    A fault diagnostic method utilizing signed directed graph is proposed. In this paper, a modified fault diagnosis method which has higher diagnostic accuracy than the aforementioned method's diagnostic accuracy is proposed. The proposed method uses conditions for cause-effect relationship among state variables. Furthermore, the performance of the proposed method and criteria is demonstrated by use of mini-plant.
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  • Shigeyuki Tomita, Yoshirou Tokumasu, Kazuhiro Ienaga
    1996 Volume 22 Issue 5 Pages 1018-1030
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Designing artifacts is a common although a vague task in a sense that neither intention of the designer nor his expertise exploited there appears explicitly in the output of the design process. In order to make the process transparent, we propose a computer based system together with a knowledge base for designing chemical plants in terms of functional design.
    Taking design specifications as its input, the system generates a hierarchy of functions, each of which can be realized by either a unit or some subassembly. At the same time, it examines whether all conditions required for realizing each function, which are premised in the knowledge base, have been satisfied so that it can provide the designer with appropriate error messages.
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  • Teiji Kitajima, Hirokazu Nishitani, Atsuhiko Saitoh, Shinji Hasebe, Io ...
    1996 Volume 22 Issue 5 Pages 1031-1038
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This paper describes an autonomous decentralized scheduling system for the processes consisting of a sequence of production stages, each of which has parallel units. In the proposed system, an individual scheduling system belonging to each production stage gradually generates a plausible schedule by repeating the schedule generation and the data exchange among the production stages. In the process of schedule generation at each stage, the jobs processed at each unit are also decided by exchanging the scheduling data among the units in the stage. The results of example problems show that the schedule generated by the proposed system has almost the same level of performance as the one obtained by the conventional method, despite the fact that in the proposed system only the local information was used to derive the schedule at each unit
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  • Shinji Hasebe, Satoshi Taniguchi, Iori Hashimoto, Akihumi Nakajima
    1996 Volume 22 Issue 5 Pages 1039-1045
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In the optimization algorithm based on genetic algorithm (GA), the performance of the algorithm depends on the GA operators used in the algorithm. Thus, in the past years many types of operators (mutation and crossover methods) which are appropriate for the respective problems have been proposed. In this paper, an optimization algorithm using several types of GA operators is proposed. In the proposed algorithm, the effectiveness of each operator used in the generation is evaluated and the probability of using that operator is changed as the generation progresses. Therefore, when a problem is given, the selection of the operators suitable for the problem is no longer needed. Furthermore, new operators can be easily added to the algorithm without discussing the effectiveness of the operator. A scheduling system using the proposed algorithm is developed, and it is applied to the scheduling problem of a parallel-unit process. The result shows that the scheduling system using the proposed algorithm can derive reasonably good schedules, even if the type of objective function is changed.
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  • Yoshiaki Shimizu
    1996 Volume 22 Issue 5 Pages 1046-1054
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new method of linear programs, PROLP, is amenable to deal flexibly with various problem-solvings in chemical processes. It is of special advantages when a number of LPs must be solved before a final solution will be obtained. We are concerned in this paper, about the parametric problems of PROLP, and reveal the accelated efficiency in iterative applications by using the outcomes.
    First of all, we have proposed a revised method that weighs on the solution efficiency compared with the previous method. Then we have presented parametric calculations for several cases. Numerical experiments are provided to examine the performances, compared both with the previous and the reference methods, through randomly generated test problems. Furthermore, mentioning a variety of promising applications, we applied the result of RHS case to the solution of mixed integer linear programs (MILP). Finally, a site location problem was taken to verify the effectiveness of the developed MILP programs from a practical point of view.
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  • Naotake Katoh, Shigehiko Yamamoto, Yasuhiko Hayashi
    1996 Volume 22 Issue 5 Pages 1055-1061
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new design method of sliding mode control based on the construction of a Liapunov function is proposed in this paper.
    This method enables us to generate not only linear, but also nonlinear switching curves. Both numerical simulations and laboratory experiments on highly endothermic NH4-alum pyrolysis reactor control were carried out using this new design method.
    Good control performances were obtained in experiments as well as in simulations.
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  • Satoru Shingu, Hirokazu Nishitani, Hiromu Ohno
    1996 Volume 22 Issue 5 Pages 1062-1069
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It is known that nonlinear sampled-data control sometimes shows chaotic behavior. In this paper, chaos in an adaptive model predictive control system has been studied. The closed-loop behavior of the system is represented by a discrete dynamical system with a rational function of state variables. Several characteristics of the chaos in the system have been identified by providing bifurcation diagrams, attractors in the phase space, stable and unstable manifolds, and Lyapunov exponent.
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  • Susumu Hashizume, Akihiro Kaneshige, Katsuaki Onogi, Yoshiyuki Nishimu ...
    1996 Volume 22 Issue 5 Pages 1070-1078
    Published: September 10, 1996
    Released: November 12, 2009
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    Chemical batch plants and their sequential control systems are regarded as discrete event systems. There has recently been great interest in the control of these systems. This paper first formulates a control problem for discrete event systems as follows : given the controlled plant modeled by a condition/event net (C/E net) and some specification of the desired behavior described by a partial language, synthesize a controller to realize the specified behavior. It next studies the properties of this C/E net control problem and then presents a method of finding solutions. It also discusses the practical applications of the control problem to the design of sequential control systems.
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  • Hidekazu Kurimoto, Yo Kato, Kenichi Yoshikawa
    1996 Volume 22 Issue 5 Pages 1079-1083
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    By processing multi-dimensional information involved in nonlinear dynamical response, we propose an intellectual process to imitate the high ability of chemical sensing in living organisms. As an example of the application, we show an experimental result on gas sensing when a sinusoidal voltage is applied to a heater inserted into a SnO2 gas sensor. The nonlinearity in the resulting output resistance of the gas sensor is evaluated by using the algorithm of the fast Fourier transformation (FFT). It is demonstrated that one can distinguish small difference in the chemical structure in alkanes and alkenes, based on the information in the higher harmonics of the FFT.
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  • Kohshi Kawabata, Shigeyuki Tateno, Yoshifumi Tsuge, Hisayoshi Matsuyam ...
    1996 Volume 22 Issue 5 Pages 1084-1092
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A problem of optimal design of a diagnosis system for faulty sensors is formulated as a problem of minimizing the cost required to construct the allocation of sensors which realizes the required upper limit of probability of false-alarm, lower limit of systematic error and upper limit of probability of mis-alarm for the given set of sensors to be diagnosed. A concept of critical detectability is introduced corresponding to the degree of freedom of the sensor system and a method is presented to solve this problem by use of this concept and the branch-and-bound algorithm.
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  • Koji Okuda, Yasuhiro Ide, Junzo Suzuki, Sae Ohba, Junichi Isii, Jun Hi ...
    1996 Volume 22 Issue 5 Pages 1093-1102
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This paper describes our approach to propose a model-based fault diagnostic method using a directed graph. The model is composed of three sub-models a failure propagation model, a component model and a state transition model. A failure propagation model represents causal relationship among process variables. Here, a pressure low variable, a temperature high variable, and others are represented as nodes, and their causalities are represented as links. A component model represents components and parts structure of the target process. Each faulty status (pipe clogged, pump failure, and so on) is represented as a node. A state transition model is introduced to represent different process operation phase like “start-up” and “steady state.” Each state is represented as a node, and their phase transition is represented as a link. The basic concepts of diagnostic algorithms are as follows : (1) input information on abnormal process variables, (2) find primal failure causes, (3) filter the result. In this paper, model components, modeling method, and diagnostic algorithm are described. The software environment for the models is also discussed.
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  • Takeshi Fujiwara, Hirokazu Nishitani
    1996 Volume 22 Issue 5 Pages 1103-1110
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A plant operator monitors time-series data of process variables to judge the state of process, diagnose abnormal states, and to identify failure origins. In this study, a new feature extraction method which extracts simultaneously both local features such as spikes and step changes, and the trend which characterizes global changes is provided from the viewpoint of process monitoring. In this method, the continuous function interpolated from the time-series data is represented by a series of inflection points first. Each time interval between two inflection points is called an episode. Then an approximation function of the time-series data is made iteratively by way of merging these episodes. This feature extraction method is also useful for compaction of a large number of process data.
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  • Yukiyasu Shimada, Kazuhiko Suzuki, Hayatoshi Sayama, Ichiro Nojiri
    1996 Volume 22 Issue 5 Pages 1111-1123
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Operability study is a systematic technique for identifying hazards or operability problems throughout an entire facility, but requires a labor-intensive and time-consuming process. This paper presents an algorithm for a computer-aided operability study for batch plantg using knowledge engineering. The batch plant Operation consists of these three processes “charge, ” “reaction” and “discharge.” Operability study for batch plants should be carried out for each operating step. The knowledge to perform the operability study is separated into plant specific knowledge and generic data to facilitate the development of widely applicable systems. Causal relationships between input variable deviations and output variable deviations for components of batch plants are modeled using decision tables and stored in the generic data base. The plant structure (Piping and Instrumentation Diagram) and reaction types are inputted to the plant specific knowledge base. Each process variable of equipment (manipulating variables, initial conditions of state variables and operating time) is examined in sequence by searching the generic data base, using key words to describe deviations.
    A computer-aided operability study is demonstrated for a polyvinyl acetate plant using the proposed methodology.
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  • Damrong Pradubsripetch, Yuji Naka
    1996 Volume 22 Issue 5 Pages 1124-1129
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Operating procedures are usually provided in advance for the fixed initial operating conditions to be used in the real time operation. They may loose their applicability when the initial operating conditions differ from the predefined ones. To improve their flexibility in terms of operations, this paper proposes a methodology for generating the operating procedures by using plant topological data and real time process data. It is implemented in a prototype system and is applied to a pilot plant of a conventional distillation system. As a result, the proposed system can perform start-up procedures satisfactory for several cases with different initial conditions.
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  • Manabu Kano, Toshihiro Shiren, Shinji Hasebe, Iori Hashimoto, Masahiro ...
    1996 Volume 22 Issue 5 Pages 1130-1137
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In olefin plants, good performance of the pyrolysis units is one of the key elements to efficient operation of the entire facility. In order to achieve efficient operation and lessen the burden of the operators, the on-line inference system of tube-wall temperature is required. In order to estimate the tube-wall temperature by using on-line measured process variables, a two step modeling approach : 1) building a physical model based on the first principles of chemical engineering : and 2) incorporating a statistical model with the physical model so as to improve the prediction accuracy for any operating conditions, is proposed. The statistical model was built by conducting a PLS (Partial Least Squares) analysis. Application of the proposed inference system, where the PLS model is integrated with the physical model, is illustrated using operating data obtained from industrial olefin pyrolysis plants. The results show that the proposed system can predict the tube-wall temperature successfully for almost all operating conditions.
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  • Yoshifumi Tsuge, Takamasa Miura, Shigeyuki Tateno, Hisayoshi Matsuyama
    1996 Volume 22 Issue 5 Pages 1138-1146
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In the development of azeotropic distillation processes, screening potential entrainers that make separation feasible is generally acknowledged to be very difficult. In this article, an attempt has been made to develop a system for screening potential entrainers used in azeotropic distillation processes. The system has the following merits : (1) the system can present entrainers that satisfy the necessary conditions to make separation feasible through azeotropic distillation and the corresponding feasible process configurations derived from them : (2) information required by the system is qualitative, such as the existence of azeotropes, the order of boiling points of pure materials and azeotropes, and immiscibility of liquid phases. Such information can be supplied from azeotropic and liquid-liquid equilibrium databases.
    The effectiveness of the system is demonstrated on a number of practical azeotropic distillation processes.
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  • Yoshiaki Shimizu
    1996 Volume 22 Issue 5 Pages 1147-1156
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Being interested in supporting social consensus making, in this paper, we have proposed a group decision making procedure through conflict resolution in the following situation : each group has a different privilege with decision making ; the final goal should be evaluated by a few qualitative sub-goals besides quantitative ones. For this purpose, we have developed a step-wise procedure that has been popularly adapted when encountered with complicated and large-scale problem-solving. As well as at the value system design phase, we applied the analytic hierarchy process, AHP to decide weights standing for the privilege at the decision making phase. Then, after rearranging the hierarchy of the sub-goals depending on the nature, we have provided an iterative procedure to derive a final solution from a discrete optimization problem. To reduce the difficulties of multi-objective decision making thereat, we took a scoring method for total evaluation and applied the genetic algorithm as a solution method.
    Through numerical experiments applied to a planning problem of the radioactive waste management system, we have shown numerically the proposed approach is very promising for social consensus making.
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  • Masatoshi Yoshida, Syunichiro Ueno, Syuji Obi, Shigeru Matsumoto
    1996 Volume 22 Issue 5 Pages 1157-1160
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An application of modal control theory, recently developed by the authors, to the control of a double-pipe heat exchanger is presented. Since the flow rate of cold fluid is selected as a manipulated variable, the process model is described by a set of nonlinear partial differential equations. After the linear approximation of the original model near an operating point, the finite integral transform is applied to derive a state space representation. A controller is designed based on the derived reduced state space model. The result is demonstrated through the experiment with a small-sized double-pipe heat exchanger.
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  • Sang-Rok Lee, Eiichi Kunugita
    1996 Volume 22 Issue 5 Pages 1161-1166
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Steady states of a complete mixing type reactor in which exothermic and endothermic reactions proceed simultaneously vary considerably, depending on the thermal characteristics of the reactions and operating conditions of the reactor.
    In this study, a simplified method to predict multiplicity and stability of steady states is established. Shapes of a function defined as the sum of products of heat of reaction and reaction rate constant are classified into 6 types, and a number of steady states are predicted based on the relation of location between 2 isoclines on which trajectories are horizontal and vertical. The stability of steady states is determined based on the directions of trajectories in each region separated by 2 isoclines.
    By making use of the method, outlines of the region in which steady states exist, stability of steady states, and also safe operating region can be predicted.
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  • Tatsuo Go, Toshitaka Hara, Munetaka Honda, Kunio Kato
    1996 Volume 22 Issue 5 Pages 1167-1173
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The property control of high purity titanium dioxide for the perovskite of electronic materials was examined by a vapor phase oxidation process. In the production process of the titanium dioxide by the CVD method, the powder of titanium dioxide is synthesized by the reaction of the titanium tetrachloride with oxygen at high temperature. Conditions to control the powder properties in this process were investigated using pilot-scale apparatus.
    Consequently, 100% rutile crystalline powder could be synthesized by addition of steam to promote rutile formation. Also, 100% anatase could be produced of a low reaction temperature. Uniform particles in size, shape and crystalline structure were produced by the reaction of turbulent diffusion combustion and the particle size could be controlled from 0.20μm to 0.52μm by varying the diffusion rate.
    On the basis of these fundamental experiments, it became possible to continuously produce high purity titanium dioxide single crystalline powder with uniform particle size.
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  • Keiichi Koga, Ryouichi Kawakami, Kooji Kagara
    1996 Volume 22 Issue 5 Pages 1174-1179
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It is known that thiazol acid exists in two polymorphic modifications, anhydrous and 1.5 hydrate. Since new crystal forms, i. e., 0.5 hydrated crystals have been discovered, the behaviors of these polymorphs in methanol · water mixed solutions were studied by the measurements of water contents in crystals and by XRPD (X-ray powder diffraction), and the relationships between transformations of ploymorphs were elucidated.
    The transformation of thiazol acid crystals depended on the composition of methanol and water. Transformation of 1.5-hydrated crystals did not occur in 0 to 30Vol% methanol solutions, but they transformed to 0.5 hydrated crystals in 50 to 80Vol% methanol solutions, and to anhydrous crystals in 85 to 100Vol% methanol soultions. By addition of 1Wt% anhydrous crystals as seed crystals, 1.5 hydrated crystals transformed to anhydrous crystals even in 80Vol% methanol soultion. 0.5 hydrated crystals did not show transformation in 80 to 95Vol% methanol solutions, but transformed to anhydrous crystals in 100Vol% methanol solutions.
    The transformation of anhydrous crystals to 1.5 hydrated crystals was observed in 0 to 40Vol% methanol solutions, but not in 50 to 100Vol% methanol solutions.
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  • Yasuo Hatate, Hisamasa Mihara, Kazuya Ijichi, Takahiro Yoshimi, Shinic ...
    1996 Volume 22 Issue 5 Pages 1180-1184
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new type of coal gasifier, consisting of a draft tube spouted bed with circulating ceramic particles as a thermal medium, was demonstrated to produce hydrogen rich gases from subbituminous coal loaded with potassium carbonate. Examinations at a coal feed of 1 kg/h were carried out at atmospheric pressure and ca. 800 °C, employing two levels of HD (= distance between throat nozzle and draft tube), 3 and 6 mm. Although a low content of hydrogen in the produced gases was obtained due to the large amount of bypass flow (from nozzle to annulus) for HD= 6 mm, initially expected results such as no generation of tar, nearly perfect carbon conversion and 55% hydrogen content in the produced gases were achieved for HD=3 mm, proving the potential of the coal gasifier proposed.
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  • Takeyuki Naitou, Chikage Iijima, Hiroyasu Itou, Toshiro Miyahara
    1996 Volume 22 Issue 5 Pages 1185-1191
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new combustion control system for a fluidized bed incinerator being fed with unshredded municipal solid wastes (MSW) was developed and tested under the control of primary and secondary air flow rate, and the feeder speed.
    This control system corresponds to the detection of brightness in a furnace and is for the purpose of obtaining stable combustion ; also, this method could cope with recent stringent air pollution regulations. As a result, the combustion was stabilized and the concentration of carbon monoxide in the waste gas become less than 10 ppm, whereas it was sometimes about 1000 ppm in the case of no new combustion control system. In addition, a new method of the feed forward control that weakens the fluidization of sand before MSW reaches the fluidizing sand by detecting the MSW feed rate is raised ; this method will be very effective for combustion.
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  • Yousuke Kawamura, Akira Takahashi, Ali Al-Shawabkeh, Shiying Lin, Hito ...
    1996 Volume 22 Issue 5 Pages 1192-1200
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The sulfurization characteristics of calcined calcite and dolomite were examined in a packed bed reactor. The calcination and sulfurization experiments were carried out in the temperature range of 973-1, 173 K using particles of 1 mm mean diameter. The effects of diffusion coefficient of the reactant gas (SO2) in the grain product layer, pressure and pore structure on the SO2 reactivity of the calcined samples were theoretically investigated in order to predict the sulfurization characteristics under typical coal combustion conditions.
    Similar CaO conversion levels were attained by calcined calcite and dolomite. Increasing the total gas pressure resulted in a higher initial reaction rate of calcined calcite, while showed no significant influence on the ultimate SO2 sorption capacity. With the calcined dolomite, on the other hand, no effect on the initial reaction rate, nor the capacity, was found upon increasing the total gas pressure. During sulfurization, the observed lower initial rates and ultimate capacities at higher calcination and/or sulfurization temperatures were attributed to the sintering effect.
    Theoretical calculations showed that both the initial reaction rates and capacities increased with larger SO2 effective intraparticle diffusivities. Only the initial reaction rate ; however, was found to increase with increasing the SO2 grain product diffusivity.
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  • Shinichi Hasegawa, Keisuke Fukui, Syouji Hirota
    1996 Volume 22 Issue 5 Pages 1201-1206
    Published: September 10, 1996
    Released: November 12, 2009
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    A liquid ice is useful as a cold heat storage material. Heat transfer experiments were carried out for continuous formation of liquid ice in the vertical pipe where water is chilled by immiscible coolant. Experimental results showed that the direct contact of water and coolant in the vertical pipe was practicable for continuous formation of the liquid ice. As a result, or empirical correlation of capacity coefficient of heat transfer was obtained. The calculated results which were estimated by using the correlation were in good agreement with experimental results. Within the experimental range, it was made out that heat transfer efficiency and mass fraction of ice were correlated with the ratio of water and coolant mass flow rate within the experimental condition.
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  • Tatsuo Go, Nobuyasu Kato, Osamu Sakaguchi, Munetaka Honda, Kunio Kato
    1996 Volume 22 Issue 5 Pages 1207-1213
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The production process of high purity fused silica for package fillers of semiconductor elements was developed. In the silica melting process via flame combustion, a large-sized furnace made of the partially stabilized zirconia bricks equipped with a compact and highly efficient packed bed preheater was developed to increase the productivity and thermal efficiency. A continuous fusing furnace, in which the silica ingot is drawn from the furnace bottom, was developed. Since the silica was not contaminated in the furnace, the fused silica was produced in high purity. As the ingot was quenched quickly, it was of high quality with a low cristobalite ratio.
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  • Masaru Ishida, Sei Hayashi, Yoshio Yamamoto
    1996 Volume 22 Issue 5 Pages 1214-1221
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Two simulators for bulk polymerization of polystyrene were made. One was used to represent the real reactor and the other was simpler and used as process model. Through them, neural networks were constructed for both dynamic state prediction and process control.
    Dynamic state prediction to predict the change of reaction temperature was achieved successfully by applying local and global learning simultaneously. With the former learning the actual experimental data were taught, while in the latter learning, global features over a wide range of operating conditions, that were given by the process model, were taught.
    Control was examined by two kinds of network. Both local and global learning were applid by a neural network, and the reaction temperature was controlled by manipulating either the coolant temperature or the feed rate. Although its calculation is simple and fast, satisfactory control was achieved. By using a forword network, the reaction temperature was manipulated by both the coolant temperature and the feed rate. By use of two operating variables, stabler control was obtained for wider target changes.
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  • Yutaka Ohkubo, Yoshiki Takahashi
    1996 Volume 22 Issue 5 Pages 1222-1229
    Published: September 10, 1996
    Released: November 12, 2009
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    The lifting velocity of an induction-charged particle in horizontally set parallel plate electrodes was studied by both theoretical and experimental approaches.
    In the theoretical analysis, a momentum conservation equation of a particle, the first order ordinary differential equation in a lagrangian frame work, was solved to obtain the velocity field of particles by using a method of the fourth order Runge-Kutta. Thereafter, a numerical integration of the velocity field was performed to define locations of particles.
    For the experiment, by using alumina powders with A 4 paper-sized electrodes, the maximum lifting height of a particle above the upper electrode was measured to estimate the lifting velocity of a particle in the first few seconds after high voltage was supplied, and a laser doppler velocity meter was used to measure the velocity fields of particles in the subsequent period when particles were circulating between the two electrodes.
    The particle velocities obtained by the theoretical and the experimental approaches were approximately identical. A simple formula for the prediction of particle's velocity field was derived by using a curve to fit the results of the numerical simulations. This could make relations between both the Reynolds number on the basis of a particle and other dimensionless numbers consisting of both external forces and locations. The predictions with the formula showed that in the case of a small-sized particle, the velocity of particles increases with the increase in particle diameter, because of viscous force dominating and that in the case of a large-sized particle, the velocity decreased with the increase of the particle diameter because of gravity force dominating.
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  • Kenji Nakano, Masahiko Shimoda, Isami Yoshihuku, Yoshimitsu Uemura, At ...
    1996 Volume 22 Issue 5 Pages 1230-1233
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Vapor-liquid equilibria of aqueous ethanol solution containing minor components (glycerin and diols) were measured at atmospheric pressure to obtain basic data of the minor component behavior in distillation. The diols were ethyleneglycol, diethyleneglycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol and 1, 6-hexanediol. The vapor-liquid equilibrium ratio of glycerin in aqueous ethanol solution was 10-3 to 10-2, depending upon the ethanol concentration. The dependence of vapor-liquid equilibrium ratio of diols on the ethanol concentration was quite different from those of other minor components which are found in Shochu mash.
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  • Ryuichi Egashira, Takahiro Sugimoto, Junjiro Kawasaki
    1996 Volume 22 Issue 5 Pages 1234-1240
    Published: September 10, 1996
    Released: November 12, 2009
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    The permeation experiments of aromatics-nonaromatics binary model mixtures were conducted using two kinds of spray columns which formed different sizes of O/ W emulsion drops, in order to measure the overall volumetric permeation coefficients and the separation selectivities of aromatics components relative to nonaromatics components. The results of these two kinds of spray columns, and those of the packed column which were reported previously, were compared. The overall volumetric permeation coefficients of aromatics components and the separation selectivities in-creased in the order of the spray column which formed the relatively large emulsion drops, the spray column, the emulsion drops of which were rather fine, and the packed column. The packed column was the most effective permeator among the three. The separation selectivity was correlated with the parameter which corresponds to the number of inner oil droplets in the emulsion on the basis of the previous simple model for emulsion liquid membrane permeation (the multi-layer liquid membrane model). The separation selectivity increased as this parameter decreased, so that the separation selectivity of the packed column, whose number of inner droplets was smallest, was reconfirmed to be highest in the three permeators.
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  • Yasuhiko Horie, Masahito Taya, Setsuji Tone
    1996 Volume 22 Issue 5 Pages 1241-1245
    Published: September 10, 1996
    Released: November 12, 2009
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    A titania thin film was fixed on a glass plate (200 mm in length, 25 mm in width and 2 mm in thickness) at a preparation temperature of 423 K, following the hydrolysis of tetraethyl orthotitanate. Photocatalytic sterilization of Escherichia coli was conducted using the prepared titania thin film. The sterilization rate increased with the increase in amount of fixed titania ranging from 0 to 1.2 × 10-3kg/m2. The apparent sterilization rate constant was determined by applying a series-event model to experimental data. A linear relation was observed between the determined rate constant and the quantity of light absorbed by the titania thin film in the range of 0 to 1.0 J/min.
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  • Toshinaga Kawai, Norifumi Onogi
    1996 Volume 22 Issue 5 Pages 1246-1249
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method to determine the mass transfer coefficient from adsorption curves and desorption depletion curves has been proposed by one of authors. The method used time difference at the points of c/c0=0.1 and 0.9 in elution curves. By using second central moments of step response in place of Δt better results are expected. In this work, nondimensional moments were numerically calculated and charts were given to determine mass transfer rate.
    This method was applied to some experimental adsorption and desorption curves, and KFaυ values were obtained with high reliability.
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  • Kazumi Yamamoto, Kazuhiko Nishi, Meguru Kaminoyama, Mitsuo Kamiwano
    1996 Volume 22 Issue 5 Pages 1250-1254
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In radical additional solution polymerization, the viscosity increases with reaction progress. It is important to evaluate beforehand the cooling capacity of the reactor, which worsens with the process.
    In this study, a stirred batch reactor with both a paddle and a helical screw impeller were studied, and measurements were made for the dynamic changes of the film heat transfer coefficient of the cooling coil with progress of the polymer reaction. We found the change could be evaluated by the calculating heat balance of the generated heat, the viscous dissipation energy and the sensible heat change under conditions of monomer conversion and changing viscosity.
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  • Ryozo Watanabe, Nobuyuki Motoyoshi, Hideo Shidara, Masato Endo, Motoka ...
    1996 Volume 22 Issue 5 Pages 1255-1258
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Heat sterilization causes evident viscosity change of fresh cream as well as a change in other physical properties due to heat denaturation. This experimental study shows that the viscosity changes can be summarized by using a C-value defined with the calculation method here, which is found to be commonly applicable to plate type indirect heating systems and two kinds of typical steam direct contact heating systems, showing the same tendency regardless of the heating system. It is suggested that the direct heating system is better in order to get a lower viscosity change with the same sterilization effect.
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  • Katsuyuki Kubota, Takuya Fujikawa, Masaki Nakayama
    1996 Volume 22 Issue 5 Pages 1259-1262
    Published: September 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    By using a bubble column a globular protein soluble in water was continuously floated at a pH value of 5.3 near is isoeletric point in order to vemove and concentrate it tvom its aqueous solution under the co-existence of a supporting electrolyte. The obtained experimental data were summarized in terms of the dynamic surface excess (surface density), and the relationship between the excess and the bulk concentration could be formulated by a Langmuir type equation. By varying the feed concentration and the column height the transient behaviours of the excesses were also examined, and the result could be formulated by the adsorption rate equations proposed by the present authors.
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  • 1996 Volume 22 Issue 5 Pages e1a
    Published: 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1996 Volume 22 Issue 5 Pages e1b
    Published: 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1996 Volume 22 Issue 5 Pages e1c
    Published: 1996
    Released: November 22, 2010
    JOURNALS FREE ACCESS
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