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Dive into the research topics where Masaru Nakaiwa is active.

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Featured researches published by Masaru Nakaiwa.


Chemical Engineering Research & Design | 2003

Internally Heat-Integrated Distillation Columns: A Review

Masaru Nakaiwa; K. Huang; Akira Endo; Takao Ohmori; Takaji Akiya; T. Takamatsu

The heat-integrated distillation column to be addressed in this paper is a special distillation column that involves internal heat integration between the whole rectifying and the whole stripping sections. An overview of the research on this process is presented in this work. It covers from the thermodynamic development and evaluations to the practical design and operation investigations for the process. Comparative studies against conventional distillation columns are introduced and the results obtained show distinctively the substantial advantages in energy efficiency of the process over its conventional counterparts. Some relevant issues of process design and operation are to be stressed and the results of the first of its kind bench-scale plant experimentation are given in great detail. The application of internal heat integration principle to other distillation-related processes is also discussed in depth. These include heat integration within batch distillation columns, pressure-swing distillation columns that are used for the separation of pressure-sensitive binary azeotropes, and different distillation columns that have no connections at all. The prospects of the HIDiC and our future research work are then highlighted.


Computers & Chemical Engineering | 2000

Operation of a bench-scale ideal heat integrated distillation column (HIDiC): an experimental study

Kiyoshi Naito; Masaru Nakaiwa; Kejin Huang; Akira Endo; K. Aso; T. Nakanishi; T. Nakamura; H. Noda; T. Takamatsu

Abstract Experimental study of an ideal heat integrated distillation column (HIDiC) is introduced in this work. It is found that the ideal HIDiC can be operated very smoothly, with no special difficulties compared with its conventional counterparts. The higher energy efficiency of the ideal HIDiC is confirmed by the bench-scale experiments. Reflux-free and/or reboil-free operations of the ideal HIDiC are also demonstrated to be feasible by the experiments.


Computers & Chemical Engineering | 2001

Parameter analysis and optimization of ideal heat integrated distillation columns

Masaru Nakaiwa; Kejin Huang; Kiyoshi Naito; Akira Endo; Takaji Akiya; Takashi Nakane; T. Takamatsu

Abstract Parametric analysis is performed for ideal heat integrated distillation columns (HIDiC) and comparative studies are made with conventional distillation columns. Implications of process design and operation variables are clarified and heuristics are provided for the effective process design. A generalized process configuration is suggested, which is demonstrated to have both higher energy efficiency and higher flexibilities than its original configuration. Simulation studies are conducted and the obtained results confirm the conclusion.


Computers & Chemical Engineering | 1998

Operating an ideal heat integrated distillation column with different control algorithms

Masaru Nakaiwa; Kejin Huang; M. Owa; Takaji Akiya; Takashi Nakane; T. Takamatsu

The operation of an ideal heat integrated distillation column is addressed. Five control strategies, namely, single loop composition control system, multi-loop composition control system, multivariable internal model control (IMC) system, modified multivariable IMC control (MIMC) system and nonlinear process model based control (NPMC) system, are design and applied to the process. Simulation results demonstrate that all the control systems are capable of keeping both end products on their specifications. The NPMC is the best one in the operation of the ideal HIDiC. It can very smoothly realize setpoint transition and efficiently counteract external disturbances. The MIMC ranks the second for the regulatory responses to feed composition disturbances have relative longer setting time. The next comes to the multi-loop composition control system. Although it works well for the operation of the ideal HIDiC, it produces relative larger oscillations and longer setting time in the system responses. The IMC can not compete with the multi-loop composition control system because it is extremely sensitive to operating condition changes. The single-loop composition control system is the worst one for the responses of the uncontrolled product is extremely sluggish.


Computers & Chemical Engineering | 1997

Simulation oriented development of a new heat integrated distillation column and its characteristics for energy saving

T. Takamatsu; Masaru Nakaiwa; Kejin Huang; Takaji Akiya; H. Noda; T. Nakanishi; K. Aso

Abstract So far, Process Systems Engineering (PSE) has contributed to the creation and improvement of new chemical production systems, by effective and rational combination of existing elementary production units and related information treatment parts, from both design and operational view points. However, it should not be forgotten that the structure of production units or information treatment parts are already fixed and given in many cases, when such methodologies are going to be applied to practical production systems. In this paper, we show that such production units or information treatment parts themselves should be newly created and synthesized from the viewpoint of the production system as the total, in order to create more rational production systems in the coming century. Next, the development of a new heat integrated distillation column, based on the above general concept, is reported and its characteristics of energy saving are discussed from a thermodynamic viewpoint. t;**


Computers & Chemical Engineering | 2000

A New Configuration of Ideal Heat Integrated Distillation Columns (HIDiC)

Masaru Nakaiwa; Kejin Huang; Kiyoshi Naito; Akira Endo; M. Owa; Takaji Akiya; Takashi Nakane; T. Takamatsu

Abstract A new configuration for ideal heat integrated distillation columns (HIDiC) is proposed by further heat integration between its overhead product and feed. This modification makes the ideal HIDiC more self-support and imposes fewer constraints to the environment. The added heat integration is different in nature from the one between the rectifying and the stripping sections. The latter is self-regulating, while the former is not. Open-loop integrating process is produced by the added heat integration, which makes the process more difficult to control than before. It is therefore extremely important to explore the interaction and tradeoff between process design and operation. Simulation studies are conducted to evaluate the process operation feasibility and it is found that the process can be well controlled through manipulations of pressure difference between the rectifying and the stripping sections and feed thermal condition.


Biotechnology Progress | 2001

Remarkable Antiagglomeration Effect of a Yeast Biosurfactant, Diacylmannosylerythritol, on Ice-Water Slurry for Cold Thermal Storage

Dai Kitamoto; Hiroshi Yanagishita; Akira Endo; Masaru Nakaiwa; Takashi Nakane; Takaji Akiya

Antiagglomeration effects of different surfactants on ice slurry formation were examined to improve the efficiency of an ice‐water slurry system to be used for cold thermal storage. Among the chemical surfactants tested, a nonionic surfactant, poly(oxyethylene) sorbitan dioleate, was found to show a greater antiagglomeration effect on the slurry than anionic, cationic, or amphoteric surfactants. More interestingly, diacylmannosylerythritol, a glycolipid biosurfactant produced by a yeast strain of Candida antarctica, exhibited a remarkable effect on the slurry, attaining a high ice packing factor (35%) for 8 h at a biosurfactant concentration of 10 mg/L. These nonionic glycolipid surfactants are likely to effectively adsorb on the ice surface in a highly regulated manner to suppress the agglomeration or growth of the ice particles. This is the first report on the utilization of biosurfactant for thermal energy storage, which may significantly expand the commercial applications of the highly environmentally friendly slurry system.


Journal of Colloid and Interface Science | 2003

Evaluation of pore size distribution in boundary region of micropore and mesopore using gas adsorption method

Tatsuhiko Miyata; Akira Endo; Takao Ohmori; Takaji Akiya; Masaru Nakaiwa

This paper discusses an accurate method of pore size distribution evaluation in boundary regions of micropores and mesopores using the gas adsorption process on the basis of the capillary condensation theory, which is liable to be underestimated with the existing BJH and DH methods. A typical nitrogen adsorption isotherm for highly ordered mesoporous silica, which has cylindrical pores with diameter smaller than 4 nm, is considered to be type IV and it is well known for the steep increase of the amount adsorbed through capillary condensation in the region of the relative pressure P/P0 smaller than 0.4. In calculating the distribution of the pore size from the change of the amount adsorbed due to capillary condensation, it is important to accurately predict both the multilayer thickness t of the adsorbed nitrogen molecules and the critical radius rc where capillary condensation occurs. It is necessary to consider the curvature of the adsorption layer-gas phase interface when predicting the multilayer thickness t of nitrogen adsorbed within the pore of highly ordered mesoporous silica. Revision of the Kelvin equation is also required when rc is to be predicted. While the predicted value of t based on the Broekhoff and de Boer theory is matched well with the value of t which is actually measured using highly ordered mesoporous silica, and the predicted value of rc based on the GTKB-Kelvin-cylindrical equation that has been revised considering the effect of the interfacial curvature on the interfacial tension of the adsorption layer-gas phase interface is matched with the value of rc which is actually measured using highly ordered mesoporous silica. A combination method of the Broekhoff and de Boer equation and the GTKB-Kelvin-cylindrical equation is proposed as a means of accurately evaluating, from the nitrogen adsorption isotherm, the pore size distribution in the highly ordered mesoporous silica in boundary region of micropore and mesopore. The proposed new method of pore size evaluation features high accuracy and offers the convenience of obtaining the pore size distribution without repeated calculations by employing the same algorithm as DH method. The pore size predicted by the Halsey equation and the Kelvin equation of the conventional DH method is about 20% smaller than the pore size predicted by the newly proposed evaluation method.


Energy Conversion and Management | 1996

Evaluation of an energy supply system with air separation

Masaru Nakaiwa; T. Akiya; M. Owa; Y. Tanaka

A high performance energy supply system (HiPESS) by use of liquefied natural gas (LNG) is proposed, which is one of the promising electric energy supply systems to accomplish less pollutant emissions in the exhaust. By using methane as the fuel and high purity oxygen as the oxidizer, neither NOx nor SOx are ideally generated. In addition, to control the combustion temperature, carbon dioxide is recycled from the flue gas as the dilution gas. As the exhausted gas consists of only carbon dioxide and water, it is easy to separate, isolate, and treat carbon dioxide. To produce high purity oxygen economically, a cryogenic air separation system is applied by introducing the cold energy of LNG and modifying the conventional process. The electric power consumption is potentially reduced by 66%, compared with the conventional system. By installing the air separation system, the efficiency of HiPESS is also lowered by around 10% (if compared with a conventional power plant). However, this is not necessarily negative because HiPESS will make a great contribution towards preservation of the global environment.


Microporous and Mesoporous Materials | 2001

Synthesis of submillimeter-thick films of surfactant templated mesoporous silica

Shinsuke Nagamine; Akira Endo; Masaru Nakaiwa; Takashi Nakane; Ken-ichi Kurumada; Masataka Tanigaki

Abstract Submillimeter-thick mesoporous silica films using tetraethoxysilane (TEOS) as a silica source and the hexagonal mesophase of cetyltrimethylammonium chloride as a template were prepared by solvent evaporation method. The effects of H2O/TEOS molar ratio and drying temperatures on the macroscopic morphology and mesostructure were investigated. Higher H2O/TEOS ratio and higher drying temperature gave a more transparent and smooth-surfaced product. With increasing H2O/TEOS ratio, the order of the mesostructure in the product film was reduced, resulting from the slow formation of surfactant mesostructure and fast silicate gelation. The pore size showed an increase with increasing H2O/TEOS ratio, suggesting mediation by the water layer between the micellar surface and the silicate. The drying temperature affected the rate of silicate condensation and the solvent evaporation, both factors that influenced the mesostructuralization of surfactant molecules. A high drying temperature facilitated the gelation of silicate rather than the evaporation of solvent, resulting in a less ordered mesostructure.

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Akira Endo

National Institute of Advanced Industrial Science and Technology

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Takao Ohmori

National Institute of Advanced Industrial Science and Technology

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Takuji Yamamoto

National Institute of Advanced Industrial Science and Technology

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Takaji Akiya

National Institute of Advanced Industrial Science and Technology

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Kejin Huang

National Institute of Advanced Industrial Science and Technology

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Koichi Iwakabe

National Institute of Advanced Industrial Science and Technology

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Keigo Matsuda

National Institute of Advanced Industrial Science and Technology

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Toshinari Nakanishi

National Institute of Advanced Industrial Science and Technology

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