Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

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Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/er.5312

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/er.5312

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.scs.2019.101808

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Publishing type：Research paper (scientific journal)   Publisher：Iron and Steel Institute of Japan  

DOI： 10.2355/tetsutohagane.tetsu-2019-125

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Language：Japanese  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Ltd  

High-temperature adsorptive heat transformer for steam generation has been experimentally investigated by introducing composite zeolite/CaCl2-water working pair based on a direct contact method. Composite adsorbents are prepared by immersing zeolite into different mass concentrations of CaCl2 solutions. SEM (Scanning Electron Microscope) is used to observe the surface structure of the composite zeolite. XRF (X-Ray Fluorescence) is selected to analyze the element mass ratios in adsorbents. BET (Brunauer-Emmett-Teller models) is employed to calculate the pore characteristic of pores inside zeolite. Characterization results confirm the success of preparation for composite zeolite. Adsorption properties including equilibrium water uptake and integral adsorption heat are measured for basic evaluation. Overall volumetric adsorption heat is increased by 13.1% for CA40% (immersion of zeolite in CaCl2 solution concentration at 40%) compared with that for 13X. Cyclic experiments are conducted to test the design of system. Superheated steam above 200 °C is generated for 13X and different composite zeolites from hot water below 80 °C. Dry gas at 130 °C is used for regeneration. Gross temperature lift is more than 100 °C for single stage zeolite adsorptive heat transformer. Dynamic steam generation on interface between water and zeolite is enhanced with more heat released by using composite zeolite. Subsequently, adsorption equilibrium is easier to be achieved inside the whole range of the packed bed. Effective time ratio for steam generation is elevated by 18.6% for CA40% compared with that for 13X. Mass of generated steam is raised by 12.9% simultaneously. Both the time and mass of generated steam have been obviously promoted with the increase of CaCl2 impregnated in zeolite. COPex (Exergy Coefficient of Performance) is kept constant while SHP (Specific Heating Power for steam generation) is increased by 12.6%.

DOI： 10.1016/j.enconman.2019.02.040

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Publishing type：Research paper (scientific journal)  

The color tone of pigments is affected by various factors such as crystal structure and particle size. These characteristics should be determined by synthesis condition. In this study, the influence of cobalt source on the color tone of cobalt blue pigment was investigated. Cobalt blue (CoAl2O4) was synthesized by solid-state reaction method. Co3O4 and Co(OH)2 with two different particle sizes were used as the cobalt source, and γ-Al2O3 was used as the aluminum source. The products were characterized by spectrophotometry, XRD, SEM, and TG/DTA. It was revealed that the chroma of the synthesized cobalt blue depends on the cobalt source. The cobalt blue synthesized using smaller size Co(OH)2 showed most vivid color. It was suggested that the number of the contact points between the starting materials increased with decreasing the particle size, leading to the progress of the reaction.

DOI： 10.4164/sptj.56.446

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Physics Publishing  

The increase in temperature, reduction in partial pressure, reduction in concentration, purging with an inert fluid, and displacement with a more strongly adsorbing species are the basic things that occur in the practical method of desorption. In this study, dry gas at constant temperature and pressure was employed as the aid to reduce the partial pressure in the water desorption on the zeolite 13X. The objective of this study is to confirm the feasibility of desorption using dry gas experimentally and numerically. The implication of heat and mass transfers were numerically investigated to find the most influential. The results of numerical simulation agree with the experimental ones for the distribution of local temperature and average water adsorbed in the packed bed.

DOI： 10.1088/1757-899X/344/1/012002

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Chemical Engineers, Japan  

The performance of steam generators to generate high-temperature steam using waste heat from industrial processes was investigated. Two types of steam generators were constructed. One is a bench-scale cylindrical generator having similar structure to the laboratory-scale reactor used in the authors’ previous research. The other is a scaled-up generator whose flow passage area is extended to store a large amount of adsorbent for further scale-up on practical application. Temperature measurements in the bench-scale generator in the atmospheric steam generation process showed that a high-temperature region is formed above the water level due to adsorption of water vapor, while a low-temperature region below saturation temperature is formed below the water level. The mass of steam generate d per unit mass of adsorbent increased with increasing energy supplied from the regeneration air and approached an asymptotic value depending on the temperature of the regeneration air. The mass of steam generated per unit mass of adsorbent increased with decreasing heat capacity of the generator.

DOI： 10.1252/kakoronbunshu.44.71

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Society of Powder Technology  

A cobalt blue pigment having a core/shell structure was synthesized by solid phase synthesis of coated particles having Co(OH)2 particles adhered onto Al2O3 particles. In this research, the effect of mixing conditions on the color tone of synthesized pigment was investigated. As a result, it was found that the mixing time greatly affected the amount of adhered Co source particles, and the pressing force during mixing affected inhomogeneity of adhered amount of Co source particle on Al source particle surface. However, it was found that the inhomogeneity of the amount of Co source particles is small as the influence on the color tone of the calcinated product by diffusing onto the alumina surface of Co ions during calcination at high temperature. In addition, when the mixing conditions were not appropriate and the coating amount of the Co source particles on the Al source particles was small, the lightness of the product was high and the chroma was low. One reason for this is considered to be a decrease in the shell thickness generated by the decrease in the amount of Co source particles deposited. It was also suggested that the formation of black tri-cobalt tetroxide, which is an unreacted Co source not adhering to the Al source particles, is also the reason of the decrease of chroma of the product.

DOI： 10.4164/sptj.55.165

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

For the effective utilization of unused thermal energy, the novel adsorption heat pump system for generating high-temperature steam is proposed. This system adopts a direct heat exchange method to the adsorption heat pump to increase heat transfer rate between adsorbent and heat transfer fluid. The heat pump system consists of two processes: steam generation process and regeneration process. In the steam generation process, water is directly introduced to the adsorbent. In the regeneration process, dry gas is introduced to the adsorbent. In this study, the performance of the system is numerically evaluated. The efficiency of the heat pump system is calculated by the ratio of enthalpy of product steam to input energy. To calculate the enthalpy of steam, mass of steam generated is estimated based on the progress of the regeneration process. Input energy of the heat pump system consists of the blower power to introduce dry gas and the thermal energy to heat dry gas. The effect of the operating condition on the performance of the steam generation process is studied. It is found there is the appropriate regeneration time to maximize the efficiency of the heat pump system.

DOI： 10.1063/1.4968252

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Begell House Inc.  

An adsorption heat transformer system based on a direct-contact heat exchange method to elevate the hot water temperature level has been proposed. Superheated steam over 150°C was directly generated from hot water. A mathematical model is developed to investigate the effect of zeolite particle size on the transient mass and heat transfer during the generation process. This model features a three-phase calculation and a moving water-gas interface. The calculations are conducted in the zeolite-water and zeolite-gas regions. The numerical results show the maximum temperature in both zeolite and the generated steam gradually decreases as the zeolite particle size increases.Meanwhile, the adsorption rate becomes slower, which takes longer for the packed bed to achieve adsorption equilibrium. The steam generation time is the same for different particle sizes, while the average steam generation temperature declines with the increase in particle sizes. After the preheating process, the maximum temperature in steam slightly decreases for small particle size but obviously increases for large particle size. The gross temperature lifts are the same regardless of the changes in particle size. The steam generation time remarkably expands to almost the whole range of the process. The average temperature for steam generation is dramatically upgraded for large sized particles with the preheating process. Future work will focus on experiments for different sizes of zeolite and packing density to enhance the steam generation process.

DOI： 10.1615/SpecialTopicsRevPorousMedia.2016017261

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Verlag  

Concerning the global warming due to large CO&lt
inf&gt
2&lt
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emission, the efficient use of coal becomes important for getting sustainable energy production. Coal gasification under CO&lt
inf&gt
2&lt
/inf&gt
-rich condition is expected to be an effective way to produce a concentrated and pressurized carbon dioxide stream, resulting in reduction in separation energy of CO&lt
inf&gt
2&lt
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for CCS. Moreover, the soot formation, which is of significant environmental concern, is still being neglected in the past studies of coal gasification. A one-step soot formation reaction mechanism is proposed in this study and implemented in numerical simulations of coal gasification with the aim of describing the gasification behaviors in a two-stage entrained-flow gasifier. In addition, the effects of O&lt
inf&gt
2&lt
/inf&gt
ratio and CO&lt
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2&lt
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concentration on soot concentration, syngas heating value and carbon conversion are numerically studied in an effort to increase the syngas production. The Eulerian–Lagrangian approach is applied to solve the Navier–Stokes equation and the particle dynamics. Finite rate/eddy dissipation model is used to calculate the rate of nine homogeneous gas-to-gas phase reactions including soot formation and soot oxidation. While only finite rate is used for the heterogeneous solid-to-gas phase reactions. It is found that formation of soot enhances the H&lt
inf&gt
2&lt
/inf&gt
production in the gasifier. Carbon conversion gradually increases with an increase in O&lt
inf&gt
2&lt
/inf&gt
ratio, while producing a low heating value syngas beyond a certain limit of O&lt
inf&gt
2&lt
/inf&gt
ratio. In contrast, an increase in CO&lt
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2&lt
/inf&gt
concentration in the gasifier increases heating value of product syngas.

DOI： 10.1007/s40095-015-0173-1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A novel zeolite water adsorption heat pump system based on a direct-contact heat exchange method to generate steam from low-grade waste gas and water has been proposed and examined experimentally. Superheated steam (200 degrees C, 0.1 MPa) is generated from hot water (70-80 degrees C) and dry air (100-130 degrees C). A dynamic model for steam generation process is developed to describe local mass and heat transfer. This model features a three-phase calculation and a moving water gas interface. The calculations are carried out in the zeolite water and zeolite gas regions. Model outputs are compared with experimental results for validation. The thermal response inside the reactor and mass of steam generated is well predicted. Numerical results show that preheat process with low-temperature steam is an effective method to achieve local equilibrium quickly, thus generation process is enhanced by prolonging the time and increasing mass of the generated steam. Besides, high-pressure steam generation up to 0.5 MPa is possible from the validated dynamic model. Future work could be emphasized on enhancing high-pressure steam generation with preheat process or mass recovery operation. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.applthermaleng.2014.11.050

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Convection heat transfer in a shell-and-tube heat exchanger using sheet fins is numerically investigated. Heat and mass transfers in the heat exchanger are modeled under steady state to estimate the heat transfer rate and the pressure drop for various geometries of the heat exchanger. Based on the numerical results, the Nusselt number and pressure drop are formulated for practical applications. For convenience, similar expressions to those of conventional shell-and-tube heat exchangers, that is, the functions of dimensionless numbers such as the Reynolds number, are derived. In these equations, the geometry of the heat exchanger, fin efficiency, and contact thermal resistance are included as major factors. On formulating the equation for the overall heat transfer rate, it is found that the heat transfer coefficient for the heat exchanger with a fin does not correspond to the combination of the heat transfer coefficient of bare tube surface and the fin. This is because the heat exchange area is substantially limited especially at the narrow space between the tube and the fin. A correction factor for the substantial heat transfer area is therefore introduced. These formulated equations are helpful for installing sheet fins in manufactured heat exchangers. Using the formulated equations, effective conditions to enhance heat transfer rate by the fin are established, taking into account the increase in pressure drop. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijheatmasstransfer.2014.11.033

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

To reduce CO2 emission from the iron and steel making process, a novel steam generation system using waste hot water is proposed to use waste heat effectively from the process. This system adopts a direct heat exchange method for the adsorption heat pump to increase the heat transfer rate between the adsorbent and heat transfer fluid. In this study, the performance of the system is evaluated according to the mass of steam generated during the cyclic operation. The regeneration process is first studied taking the transport phenomena in the generator into account. The mass of steam generated is then estimated based on the distributions of water content and temperature in the generator. The results from the model exhibit good agreement with the experimental results. The effect of the operating conditions on the performance of the steam generation process is studied. It was found that there was an appropriate regeneration time to maximize the mass of steam generated during the cycle. For the effective use of adsorption heat, reuse of the water drained from the steam generation process (Drainage Recycling) is proposed. As a result, recycling the drainage water is a practical and helpful method to improve the performance of the system.

DOI： 10.2355/isijinternational.55.448

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The combustibility of Taiheiyo coal and oak char in the tuyere and raceway of an ironmaking blast furnace was simulated. The effects of injection rate, O-2 concentration and particle diameter on combustibility were studied. Numerical results showed that increasing the O-2 concentration from 23 to 27 wt.% resulted in higher combustibility of both solid fuels. However, this effect was insufficient to increase the combustibility of oak char at high injection rates because its volatile content was lower than that of Taiheiyo coal. Temperature and reaction fields were sensitive to both combustion heat and volatile content. A longer raceway or smaller particle size was required to obtain the same combustibility of biochar as of the reference coal. If Taiheiyo coal with a particle diameter of 70 mu m was used at a high injection rate of 200 [(kg solid fuel)/(1000 Nm(3) feed gas)] with hot blasts containing 27 wt.% O-2, the particle diameter of oak char was required to be 60 mu m to obtain the same combustibility. These predictions reveal the potential of pulverized biochar injection instead of conventional pulverized coal injection in blast furnace ironmaking. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.fuproc.2013.01.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IRON STEEL INST JAPAN KEIDANREN KAIKAN  

The possibility of injecting pulverized biochar instead of conventional pulverized coal in blast furnace ironmaking was investigated numerically. More detailed reactions including the water-related reactions were considered here. The combustion process from the tuyere to the raceway of a blast furnace was simulated. Oak char (volatile matter wt.% dry basis, VM = 27.11 wt.%-db) provided a lower temperature than Taiheiyo coal (VM = 44.60 wt.%-db). Increasing the O-2 concentration from 23 to 27 wt.% resulted in a higher combustibility of both solid fuels. However, the effect of increasing oxygen cOncentration was still insufficient for the Oak char at high injection rates because of its inadequate volatile content. Biochar properties become increasingly important as the injection rate increases. Compared with Oak char that provided a combustibility of 68% at an injection rate of 200 [(kg solid fuel)/(1 000 Nm(3) feed gas)] and hot blast of 27 wt.% O-2 concentration, Oak char 1 (VM = 32.09 wt.%-db) had a higher combustibility of 71%.

DOI： 10.2355/isijinternational.54.1521

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Language：English   Publishing type：Research paper (scientific journal)  

Mist cooling is a technology to cool high temperature surfaces using an evaporative latent heat associated with the vaporization of atomized droplets. It has higher cooling capacity than the conventional cooling techniques such as forced convection, as it takes advantage of relatively large values of evaporative latent heat. In this paper, fine mist cooling as a high heat removal technology has been applied to the cooling of a high temperature work material. A threedimensional numerical simulation has been developed in order to investigate the behavior of fine mist particles, flow of gas phase and temperature of work material. Model predictions show that water droplets hardly evaporate in the gas phase of the analytical domain
approximately 45% of fine mist particles flow out of the analytical domain and approximately 55% of fine mist particles collide on the work material. 10%-20% of collided water droplets evaporate on the work material and 80%-90% of collided water droplets stay on the work material under steadystate condition. Collision of fine mist particles on the work material has a high frequency in the central part of the device and the collision frequency of fine mist particles decreases with an increasing distance from the center of the work material. As a result, the surface temperature of the work material is comparatively low in the central part of the work material due to the evaporative latent heat of fine mist particles and becomes higher toward the outside of the work material. © 2014 by Begell House, Inc.

DOI： 10.1615/ComputThermalScien.2014005831

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Begell House Inc.  

Performance of a novel adsorption heat pump system with zeolite-water pair for generating high-temperature steam is investigated. The adsorption heat pump system adopts a direct heat exchange method to overcome the low heat transfer rate between packed bed and heat transfer fluid. As a thermal storage process in the heat pump system, the regeneration of zeolite using dry hot gas is carried out. For a thermal discharge process in the heat pump system, water is introduced to the zeolite packed bed as not only adsorbate but also heat transfer fluid. A direct contact of water and zeolite results in evaporation of excess water due to the release of adsorption heat from zeolite. In the direct heat exchange method, large surface area of zeolite packed bed can be used for the convection heat transfer as well as the reaction. However pressure drop especially for introducing the dry gas would increase. Pressure drop is closely related to the blower load and should be therefore reduced for the practical utilization. In this study, reduction in the pressure drop during the regeneration of zeolite is investigated. An insert made of wire mesh is used to increase the porosity of the zeolite packed bed. As a result, while pressure drop can be reduced, the rate of regeneration of zeolite changes little. This can be attributed to the deviation of air flow by using the inserts. The appropriate conditions to reduce the pressure drop are studied.

DOI： 10.1615/ihtc15.ecs.009174

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Cyclic steam generation experiments from a novel zeolite-water adsorption heat pump were carried out to demonstrate the feasibility of recycling hot water and low-grade waste gas. A direct heat exchange approach was introduced to enhance heat transfer and decrease system size. The experimental steam generation rate per unit mass of zeolite is 2.44 x 10(-5) (kg-steam/kg-zeolite)/s at regeneration for 1200 s, which is 10% larger than that for 3600 s. A one-dimensional model describing transport phenomena during regeneration was developed to estimate temperature distributions and local water content in zeolite at the end of regeneration. Based on the numerical results, the mass of steam generated in the subsequent process was calculated. Then, the cyclic steam generation rate can be estimated. Calculated results on steam generation rate agree with the two sets of experimental data. The calculation reveals a maximum in the steam generation rate with the change in regeneration time. Predictions also show the possibility of high-pressure steam generation from this system. (c) 2012 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.expthermflusci.2012.11.020

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Significance: The effects of mixed solvents on the shape of films formed on a hydrophilic surface from polymer solute droplets were investigated experimentally. The film shape depended on the two solvents used, and the mixing ratio. It was also found that the flow direction was dominated by solute-derived rather than solvent-derived Marangoni flows. Consequently, the changes in the shape of the film could not be explained only by the Marangoni flow direction. © 2013 American Institute of Chemical Engineers.

DOI： 10.1002/aic.14031

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Language：English   Publishing type：Research paper (scientific journal)  

A fluidized bed was applied in a PM-removal device to remove PM2.5 effectively by the adhesion force. The effect of PM diameter on PM collection characteristics in the device was investigated experimentally. Numerical simulation was also performed to analyze the adhesion behavior of PM on the surface of particle in the fluidized bed and to compare the results with the experimental data. The experimental results show that the dominant factor of PM flow (except for flow resistance) changes from gravity to the adhesion force with decreasing PM diameter between 8.95 μm and 2.25 μm. When PM diameter is less than 2.25 μm, PM is effectively collected by the adhesion force. Model predictions are in reasonably good agreement with the experimental observations. Model predictions indicate that PM is mainly collected in the area with a higher volume fraction of bed particles and is rarely collected in bubbles in the fluidized bed. © 2013 The Society of Chemical Engineers, Japan.

DOI： 10.1252/kakoronbunshu.39.60

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AIChE  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

An adsorption heat pump with a direct contact system for steam generation has been developed and the feasibility of the proposed system was confirmed both theoretically and experimentally. The basic cycle for the system has been proposed to use zeolitewater working pairs in the p-T-x equilibrium curve. To generate steam above 150 degrees C from low-energy level water at 80 degrees C, a direct contact adsorption heat pump prototype was constructed. The experimental results show that steam could be generated by the direct contact system and the relationship between the amount of water adsorbed and the change in temperature with time is discussed. This study is expected to serve as a foundation for developing continuous adsorption heat pump systems for steam generation. Copyright (c) 2011 John Wiley & Sons, Ltd.

DOI： 10.1002/er.1855

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

To increase syngas production and minimize soot, polycyclic aromatic hydrocarbon (PAH), and CO2 emissions resulting from biomass combustion, the evolution of biomass volatiles during O-2/CO2 gasification was simulated. A highly detailed soot formation reaction mechanism flowing through the reactor, involving 276 species, 2158 conventional gas phase reactions and 1635 surface phase reactions, was modeled as a plug flow reactor (PFR). The reaction temperature and pressure were varied in the range 1073-1873 K and 0.1-2 MPa. The effect of temperature on product concentration was more emphasized than that of pressure. The effect of O-2/CO2 input on product concentration was investigated. O-2 concentration was important in reducing PAHs at low temperature. Below 1473 K, an increase in the O-2 concentration decreased PAH and soot production. However, if the target of CO2 concentration was higher than 0.22 in mass fraction terms, temperatures above 1473 K reduced PAHs and increased CO. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2012.01.068

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

An experimental study using a flow reactor and a numerical simulation with a detailed kinetic model have been performed to investigate the reaction mechanism of NO formation from pyrrole decomposition. The experiments have been conducted in a quartz flow reactor by using a mixture gas of pyrrole, O-2 and H2O with N-2 as a balance gas at atmospheric pressure and temperature range 800-1400 K. The detailed kinetic model consists of 505 elementary reactions and 89 chemical species, and the plug flow calculations have been carried out under same conditions as experiments. Model predictions are in reasonably good agreement with the experimental data for NO formation from pyrrole. Model predictions indicate that the main reaction pathways from pyrrole to HCN are direct reaction by pyrrole pyrolysis and pyrolysis reaction of HNCPROP (HN=CHACH=C=CH2) generated by ring scission reaction of pyrrole. HCN is converted to N-2 or NO via NCO and about 90% of nitrogen in pyrrole is transformed to N-2 or NO at the temperature of above 1400 K. The residence time has little influence on the reaction rate and the reaction rate largely depends on the reaction temperature. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2011.09.032

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The effort for increasing syngas production and reducing soot and CO2 emissions from coal combustion is important for cleaner and more efficient use of coal for energy production. The primary reactions of coal volatiles for soot formation mechanism were numerically investigated under pyrolysis (thermal decomposition), partial oxidation (O-2 gasification) and O-2/CO2 gasification conditions. Soot formation was modeled in a plug flow reactor (PFR) with a detailed reaction mechanism containing 276 species, 2158 conventional gas phase reactions and 1635 surface phase reactions. The reaction temperature and pressure were maintained in the range 1273-1873 K and 0.1-2 MPa, respectively. The effect of temperature on product concentrations appeared more significant compared with pressure effect. In the viewpoint of special attention regarding O-2/CO2 blown gasification, the effect of O-2/CO2 input on the production of major combustion species was investigated. The O-2 input became important in reducing PAHs/soot at low temperature. However, if the gas mixture input had a high CO2 concentration, higher temperature and pressure provided in eliminated PAHs/soot and increased CO. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fuel.2011.10.003

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER-VERLAG BERLIN  

Coal gasification with CO2 rich gas mixture is one of several promising new technologies associated with CO2 reduction in the atmosphere. Coal gasification with high CO2 concentration is suitable for producing large amount of syngas. However, an increase in CO2 concentration will result in lower gas temperature in the reactor. In this paper, a similar gas temperature profile in CO2/O-2 mixtures to that of coal gasification in air is predicted by observing the effects of CO2 concentration. The coal gasification model considered in this calculation is composed of devolatilization model, char gasification model and gas phase reaction model. Reaction rate equation of n-th order type with the Random Pore Model is applied to the char gasification reaction. Influence of inlet particles size is also studied. It is found that 20 mu m particles in 21%O-2/79%CO2 and 100 mu m particles in air (21%O-2/79%N-2) result in a similar gas temperature profile during coal gasification. The outlet gas mixture with the same calorific value as from air blown coal gasification can be obtained if air is replaced by 50%CO2/29%N-2/21%O-2 mixtures

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER SOC MECHANICAL ENGINEERS  

More reduction in energy consumption is requested to the industrial processes. In particular, large quantity of waste water at low temperature is released from chemical and steel processes. In this study, adsorption/desorption process of zeolite and water pair were selected to generate steam from water at low temperature. Contacting water liquid and zeolite directly, adsorption heat released from zeolite makes excess water evaporate. Basic experiments for adsorption/desorption process were carried out. First of all, adsorbents with different type were tested to find the candidate of the proposed system, and then suitable adsorbent was selected. From the basic adsorption experiment, generation of steam from the water liquid was confirmed by the proposed system. In the desorption process, hot dry gas was introduced to the adsorbent. The effect of gas temperature and its flow rate was investigated. The performance of the system was theoretically investigated based on overall heat and mass balances. As a result, the ratio of enthalpy of recovered steam of 140 degrees C to input waste water of 80 degrees C was around 6 when adsorption process was only considered. On the other hand, the ratio was 0.57 when waste heat was utilized for the desorption process. However if waste heat such as exhaust gas can be utilized for the desorption process, the ratio, that is, the efficiency would increase.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

The effects of mixed solvent on polymer film morphologies formed from droplets of solution dried on a substrate with circular hydrophilic surfaces patterned on a hydrophobic surface were investigated. Several solvent mixtures were used, with polystyrene as a solute at various concentrations. Droplets formed a thin film after shrinking on the hydrophobic surface to the boundary between the two surfaces. The results from the chosen binary solvent pair combination showed that ring films tend to shift to flat films at each mixing ratio as the initial solute concentration increases. Marangoni flow arising from the concentration profiles of the solvents and solute was discussed. However, no evidence was found for Marangoni effects changing the experimental film morphologies when considering the effect of solute. Instead, the viscosity and contact angle at self-pinning was found to affect film morphology.

DOI： 10.1252/jcej.12we085

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

A mathematical model has been developed to predict mass and heat transfer during the steam generation process in a novel zeolite-water adsorption heat pump system. This model features a three-phase calculation and a moving water-gas interface. The calculations were carried out in the zeolite-water and zeolite-gas regions. An enthalpy form is adopted to account for water evaporation. Model outputs are compared with experimental results for validation. The thermal response in the reactor is well simulated with a relative error between the calculated and experimental steam mass of 0.6% to 1.9%. The effects of operational temperatures on the steam mass are also investigated numerically. Raising the water temperature rather than zeolite temperature enhances the mass of steam produced. The peak temperature in the reactor increases from 300 to 311 degrees C as initial zeolite temperature rises from 80 to 120 degrees C.

DOI： 10.1252/jcej.12we016

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

A direct heat exchange system using zeolite 13X-water working pairs is expected as an effective process to generate steam more than 150 degrees C from water below 100 degrees C. As a basic study, steam at 100 degrees C from water at 80 degrees C was investigated. The effects of the direction of feeding water in the adsorption process were experimentally investigated. The experimental results for the feeding from the bottom show that mass of generated steam reached almost 90% of the theoretical value obtained by heat mass balances. However, the performance, that is, the mass ratio of generated steam to the inlet water was around 6.5% because an abundance of water should be introduced to get contact between zeolite particle and water. Feeding water from the top was, therefore, investigated to increase the performance of steam generation with various nozzle configurations. Although the mass of the product steam was less than that for feeding water from the bottom, the mass ratio was improved to 13% by using 14 nozzles. This is because the nozzle installation enlarged the contact area between water and zeolite with a small amount of water.

DOI： 10.1252/jcej.11we128

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

The breakup processes of polymer solution droplets deposited on chemically strip-patterned surfaces are investigated experimentally. Polystyrene is used as solute while various liquids are used as solvents. Breakup of the liquid film is found to progress by iterations of self-pinning on lyophilic channels and receding of the contact line on lyophobic channels. Accordingly, formation of the polymer thin film is incomplete when the contact lines are not pinned on the lyophilic channels, or when they are pinned on the lyophobic channels. To induce a Marangoni effect on breakup, binary solvent mixtures are used. For several mixtures, thin liquid films are elongated on the lyophilic channels, enhancing breakup. Such mixtures exhibit complete wetting on homogeneous lyophilic surfaces as a result of the Marangoni effect.

DOI： 10.1252/jcej.11we183

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

The effect on substrate temperature on the fluid dynamics in a polymer solution droplet evaporating on a substrate is investigated experimentally and numerically. It is found from the experiments that fluid velocities in the droplets increase with increasing initial substrate temperature and with decreasing initial solute concentration. A mathematical model, which takes thermal and solutal Marangoni effects into account, are numerically solved using a finite element method. The calculated fluid velocities agree with the experiment. Both experiments and calculations show that, though thermal Marangoni forces dominate the fluid dynamics, solute Marangoni forces should never be neglected. The calculations predict that solute Marangoni effects are more emphasized with decreasing contact angle.

DOI： 10.1252/jcej.11we124

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Language：English   Publishing type：Research paper (international conference proceedings)  

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This paper provides detailed investigation of Victorian brown coal char gasification in laboratory scale drop tube furnace (DTF) under CO 2/N2 mixtures. The DTF is a 2.0 m long quartz reactor consisting of two concentric tubes (diameters 50 mm and 80 mm). Morwell coal char with diameter of &lt
106μm (mean value = 50μm) is used for this investigation. This char sample was prepared in a tubular furnace under pure N2 at 823K. The char is gasified under CO2/N2 atmosphere at temperatures of 1173 and 1273K. The gas compositions from char gasification in the DTF are measured on-line using micro gas chromatography (GC). The results show that char conversion and CO concentration increases with increasing the inlet gas temperature. At 1273K, CO concentration increases due to increased rate of the char-CO2 reaction. A 3D comprehensive numerical modeling is employed to investigate the char-CO2 gasification process under various operating conditions. The calculated results are compared with experiments at two different temperatures of 1173 and 1273K using at 20 vol. % CO2 /N2 mixtures. The comparisons show a good agreement confirming the validity of the current model. We predict carbon conversion from char-CO2 gasification for various char particle sizes at elevated gas temperature (&gt
1273K). The temperature distribution in the furnace is found to be uniform under current operating conditions. It is also found that the char conversion significantly depend on the inlet gas temperature and particle size.

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The effects of pressure, composition and temperature (PCT) characteristics on the thermal response and overall reaction rates in a packed bed reactor of metal hydrides have been investigated at both constant and variable hydrogen pressures. LaNi(5) particles were used as the alloys for metal hydride formation inside a 50 mm i.d. x 185 mm height cylindrical reactor. Predictions of the thermal response and overall reaction rates were also carried out using three distinct models for the PCT characteristics: one based on Van't Hoff's equation [refer to Mayer et al. J Less Common Met 1987; 131: 235-44], another developed by [Jemni and Nasrallah. Int J Hydrogen Energy 1995; 20: 43-52, 881-891] and a new model and compared with the experimental results. The transient local bed temperature and reaction rate obtained from the predictions strongly depend on the model chosen for the PCT characteristics. Our new model provides good agreement with experiments. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijhydene.2010.12.047

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Heat transfer techniques involving phase a change process are likely to play an important role in industrial devices that require the ability to remove high heat quickly. In the present work, fine mist cooling as a high heat removal technology was applied to the cooling of high temperature work material. A three-dimensional numerical simulation was developed to investigate the behavior of water particles and temperature of work material. The calculated results were in reasonably good agreement with experimental results for cooling performance of fine mist. It was found that about 50% of mist particles collide with the work material, and 20-30% of these particles evaporate after collision.

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

In a previous report where internal flows were experimentally visualized in polymer solution droplets receding on a lyophobic surface [Kaneda et al., Langmuir 2008, 24, 9102-9109], the direction of the circulation flow was found to depend oil solvent and solute concentration. To identify the reason for this finding, the internal now in the droplet is investigated numerically. A mathematical model predicts that double circulation flows initiate after a single now develops at high Marangoni numbers, while only a single circulation flow develops at low Marangoni numbers. The dependencies of the calculated velocities on the solvent and the initial solute concentration agree qualitatively with experiment. It is Concluded that the difference of the flow directions that were investigated experimentally is due to such a change in the now structures. The effects of the contact angle and dimensions on transport phenomena in a droplet are also discussed.

DOI： 10.1021/la903245m

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER SOC MECHANICAL ENGINEERS  

Packed bed reactors are utilized for catalysts, chemical heat pumps, etc. Because the effective thermal conductivities of the packed beds of particles are generally low (approximate to 10(-1) W/mK), this matter often results in low performance and degradation of catalyst. Many heat transfer tubes with fins and/or much filler with high thermal conductivities are inserted in the packed bed reactors to improve heat transfer rate. In return to this, the volume of reactive particles packed into the reactors, or stored energy, decreases.
In this study, the effect of fin configurations on the heat transfer rate in the reactors is numerically investigated. Three. configurations of fins are studied. (I) "Sheet type" is a longitudinal fin attached on the heat transfer tubes. It is placed to connect between heat transfer tubes. (2) "Straight type" is several longitudinal fins in the half length of the tube pitch attached on the tube with radial structure. (3) "Spiral type" is many narrow rectangular fins attached on the tube with spiral structure.
To discuss the effect of fin configuration on the heat transfer generally, the heat conduction equation in the packed bed around the tube is converted to the dimensionless form. The transient temperature responses in the packed bed and fins at a uniform temperature are calculated when the temperature of the tube surface is stepwise changes. In another analytical system, a homogeneous body around the tube is assumed. To evaluate the thermal performance of the fin, apparent thermal conductivity is defined as the thermal conductivity which gives the same thermal response as that calculated in the heterogeneous system. As a result, the spiral type rather than the straight and sheet types effectively increases apparent thermal conductivity. The apparent thermal conductivity of the spiral type is two-three times larger than the straight type, and ten times as large as the sheet type. This result indicates dispersion of fins in packed bed is essential to improve the thermal response in the reactors.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER SOC MECHANICAL ENGINEERS  

To control the formation process of polymer thin films from polymer solution droplets using inkjet printings, internal flows of the droplets on substrates are studied. In our previous study [1], internal flow of polymer solution droplets receding on a lyophobic surface was experimentally visualized. It was found that the direction of the circulation flow in the droplet depended on the solvent and the initial solute concentration. In particular, the flow direction of polystyrene-anisole solution was reversed as the initial solute concentration increased. In this study, to clarify this reason, the conservation equations of momentum, energy and mass on two-dimensional cylindrical coordinate are numerically solved using a finite element method. The mathematical model considers the free convections derived by the dependencies of the density and surface tension on the solute concentration.
As a result, the dependences of the calculated velocities on the initial solute concentration agree qualitatively with the experiments. The mathematical model predicts that double circulation flows appear after a single flow develops at high initial solute concentrations, while double circulations do not develop at low concentrations. It is concluded that the difference between the flow directions investigated experimentally is due to such a change of the flow structure.
The distribution of the surface tension on the free surface is also discussed. When a local minimum of the surface tension appears on the free surface, the double circulations develop. According to the result for a low contact angle; the local minimum point shifts toward the axis of symmetry with a lapse of time, and finally erases the double circulations.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

In the present paper, the authors study the primary reactions of coal volatiles and a detailed mechanism has been made for three different environments: thermal decomposition (pyrolysis), partial oxidation (O2) and O2/CO2 gasification in a plug flow reactor to analyze the combustion component. The computed results have similar trend for three different environments with the experimental data. A systematically reduced mechanism for O2/CO2 gasification has also been derived by examination of Rate of Production (ROP) analysis from the detailed mechanism (255 species and 1095 reactions). The reduced mechanism shows similar result and has been validated by comparing the calculated concentrations of H2, CH4, H2O, CO, CO2 and polycyclic aromatic hydrocarbon (PAH) with those of the detailed mechanism in a wide range of operating conditions. The authors also predicted the concentration profiles of H2, CO, CO2 and PAH at high temperature and high pressure.

DOI： 10.1080/13647830.2010.517273

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2010f.0.666.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2010f.0.84.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2010f.0.397.0

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Heat transfer enhancement in a packed bed reactor equipped with a heat transfer tube was studied. Bundles of carbon fibers of high thermal conductivity were attached to the heat transfer tube not only to increase the effective thermal conductivity around the tube but also to improve the contact thermal resistance between the fibers and the tube. To disperse the carbon fibers in the reactor effectively, a spiral configuration was employed. The effect of the method of fixing the carbon fibers on the heat transfer rate was investigated, and a silver paste adhesive rather than an aluminum tape was found to be suitable to fix the fibers and to transfer thermal energy effectively. The spiral carbon fibers effectively improve thermal responses of the reactor because of their lower contact thermal resistance than a carbon fiber brush.

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

To conventionaly extend heat transfer area in shell-and-tube heat exchangers, a method is proposed where sheet materials with high thermal conductivities are stretched among tubes. The numerical simulations are carried out to predict the performance of heat exchanger with or without the sheets. As a result, it is found that thermal contact resistances between the sheet and tubes rather than thickness and thermal conductivity of the sheet influence overall heat transfer coefficient. In the experiments, the carbon fibers clothes (27Wm^<-1>K^<-1>) are pass zigzag though the tubes whose pitch is 20mm. The heat transfer rate between hot water flowing in the tube side and air in the shell side are measured. No substantial improvement of heat transfer is unfortunately observed experimentally due to contact thermal resistance. The method proposed in this study conclusively has a potential that the heat transfer rate improves no less than a few ten percents.

DOI： 10.1299/kikaib.75.757_1854

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Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.4164/sptj.46.162

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009f.0.103.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009f.0.553.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009f.0.597.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009f.0.702.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009.0.523.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009.0.123.0

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Language：English   Publishing type：Research paper (international conference proceedings)  

Packed bed reactor equipped with shell and tube heat exchanger was studied. Carbon fiber of high thermal conductivity was attached to a heat transfer tube to improve heat transfer rate around the tube by extension of heat transfer area. To disperse the carbon fibers in the reactor effectively, spiral type configuration was used. A silver paste adhesive rather than aluminum tape is suitable to fix carbon fibers and to transfer thermal energy effectively. This is an abstract of a paper presented at the 8th World Congress of Chemical Engineering (Montreal, Quebec, Canada 8/23-27/2009).

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Carbon fiber cloths are stretched among heat transfer tubes to extend the heat transfer area in latent heat thermal energy storage tanks. The thermal responses of the tanks into which paraffin wax as the thermal energy storage material is packed are experimentally investigated. The experimental results show that the carbon fiber cloths of only 0.4 vol.% improve the heat exchange rate in the tanks. A numerical model describing the heat transfer in the tank well predicts the experimental results. Moreover, the effect of the carbon fiber cloths on the thermal performance for a practical scale tank is numerically discussed. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cep.2007.02.001

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2008f.0.582.0

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2008f.0.679.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Packed bed reactors using metal hydride are attracting a lot of attention as potential future hydrogen storage systems, actuators, etc. However, their low effective thermal conductivities lead to low performance. In this study, carbon fiber brush with high thermal conductivity was installed in a reactor to improve the effective thermal conductivity. We found that the carbon fiber brush at 1.0 vol% reduced the reaction time by 30%. A two-dimensional mathematical model describing the heat and mass transfer was developed to predict the thermal performance. Expansion of particles due to absorption is also considered in this model. The model was compared with the experimental results, and it predicted the time variations of the averaged reacted fraction and local reactor temperature very well. The model suggests that heat transfer rather than mass transfer controls the overall reaction.

DOI： 10.1252/jcej.06WE246

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

The seesaw-oscillation of a small circular pad on a single droplet was studied both numerically and experimentally. The circular pad with a diameter of 2.0-3.8 mm onto a water or glycerol droplet with a volume of 1-10 mu L, and a bottom substrate with a smaller diameter than that of the pad were used in the experiment. The pad was then tilted and then the tilting fixture was quickly removed. The pad alternately oscillated and then finally stabilized in a horizontal position. The numerical model considering the surface tension and the viscous force of the droplet was developed and calculated using the same configurations as those in the experiment. The experimental and numerical data showed good agreement not only in terms of the oscillating frequency and damping ratio but the transient motion of the circular pad and instantaneous droplet surface shape. (c) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.precisioneng.2006.03.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Metal hydride (MH) attracts considerable attention for not only hydrogen storage devices hut also chemical heat pumps (CHPs). Many previous researchers pointed out low effective thermal conductivity of MH packed bed resulted in low performance. Indeed, several attempts have been done to improve it. However, no guideline for improving the thermal performance with heat transfer enhancement has been discussed. In this study, thermal performance for a packed bed reactor of MH is numerically investigated. Diagrams for the heat transfer enhancement are developed according to the numerical results. The previous strategies to improve effective thermal conductivity can be combined with the diagrams for the practical use.

DOI： 10.1252/jcej.07WE156

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2007.0.758.0

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Carbon-fiber cloths were installed in a latent heat thermal energy storage (LHTES) tank to expand the heat transfer area, and the characteristics of the energy charge and discharge processes were compared with the results for carbon-fiber brushes previously reported. In the charge process, carbon-fiber cloths with a volume of 0.27% of the tank volume exhibited better thermal performance than carbon-fiber brushes with a volume of 1.3%. In the discharge process, their thermal performances were the same. The thermal performance of the cloths was accordingly superior to the brushes. When the discharge characteristics were evaluated in terms of the overall fin efficiency, that of carbon-fiber cloths under the present conditions was twice as high as that without carbon fibers. An increase in volume fraction of carbon fibers resulted in higher efficiency, which reached 0.9 only at 1 vol.% of carbon fibers.

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2006f.0.145.0

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Society of Heating, Air-Conditioning & Sanitary Engineers of Japan  

Latent thermal energy storage (LHTES) tanks where carbon-fiber cloths are used to extend the heat transfer area are developed. The tanks are set in an air-conditioning system in a building, and then the performances are evaluated using imitation and practical loads. The results are compared with those of the tanks where carbon fiber brushes are installed. As a result, the carbon cloths of 0.27vol%, exhibit the equivalent thermal performance to the carbon fiber brushes of 1.3vol% during the charge process. The thermal performance of the former is apparently superior to the latter. The effect of the orientation of the cloths in the tanks on the heat transfer rate is also investigated. However it has less influence on the charge and discharge characteristics of the tanks.

DOI： 10.18948/shase.31.114_11

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2006f.0.720.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS INC  

Titania (TiO2) nanoparticles with primary diameters of less than 30 nm were produced by the thermal decomposition of TTIP and by the oxidation of TiCl4 in a cylindrical furnace reactor at 1200degreesC. Particle size, crystalline phase, and phase transformation were investigated as a function of precursor concentration and total flow rate by TEM, a DMA/CNC system, XRD, and TG-DTA. The results show that both particle size and number concentration were increased with increasing precursor concentration, and that the primary size could be controlled by changing the operating conditions. An anatase-to-rutile phase transformation occurred at TTIP concentrations above 7.68 x 10(-6) mol/l and this was enhanced with increasing precursor concentration. It is noteworthy that the transformation is independent of grain size but appears to be related to the presence of carbon impurities in the nanoparticles.

DOI： 10.1080/027868290906986

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

To understand the mechanism by which titania (TiO2) nanoparticles are generated by a CVD method, the primary nucleation mode size distributions of TiO2 nanoparticles prepared from two different chemical precursors (TTIP and TiCl4) were directly measured using a DMA/PSM/CNC system. This represents the first report of such direct measurement in the nucleation mode. These results are particularly important for experimental investigation of particle nucleation and growth, something which has never been achieved before. In the nucleation mode, titania nanoparticles with a diameter of about 2 nm were produced by nucleation. At low reactor temperatures, nucleation and surface reaction were major contributors to particle generation. At a high reaction temperature, coagulation and sintering became more important. The morphology and crystallinity of the particles were investigated by TEM and XRD as a function of temperature and precursor concentration. The properties of the titania nanoparticles, such as particle size distribution, the morphology and crystallinity, changed as a function of reaction temperature and chemical reaction rate.

DOI： 10.1252/jcej.37.1379

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

The outlet fluid temperature of a latent heat thermal energy storage unit was numerically estimated using a simplified three-dimensional heat transfer model. In this model, thermal conductivity of liquid phase assumed to have a high value, while free convection heat transfer in the liquid phase is neglected. Comparison of calculated and experimental values showed that the simplified model was able to predict the outlet fluid temperature, which was independent of the thermal conductivity of the liquid phase when the thermal conductivity exceeded a critical value. Moreover, fluid dynamics and heat transfer around heat transfer tubes were numerically predicted using a two-dimensional model that takes into account the free convection heat transfer. Comparison of the numerical results given by the two models showed that the simplified model is applicable to energy thermal storage in which free convection dominates the heat transfer rate.

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Language：English   Publisher：The Society of Chemical Engineers, Japan  

Development of chemical heat pumps and dry sorption systems using solid-gas thermochemical reactors requires determining their optimal operating conditions. Many previous studies particularly noted that the performance of solid-gas thermochemical reaction would be reduced due to low heat transfer rate in the reaction beds. In this study, enhancement of effective thermal conductivity of reaction beds was therefore studied using magnesium oxide/water reaction, which was expected to be utilized for chemical thermal storage in a cogeneration system. High thermal conductive carbon fiber was installed into a reaction bed as a brush in order to be dispersed in the whole reaction bed and improve the effective thermal conductivity. In addition to the experiment, a two-dimensional mathematical model describing heat and mass transfer as well as chemical reaction rate was formulated and solved for its evaluation. Numerical results indicated that increasing the effective thermal conductivity essentially promoted the magnesium oxide/water chemical reaction rate. Qualitative agreement between experimental and theoretical results was obtained. Moreover, optimum operating conditions for a solid-gas thermochemical reactor were also discussed according to the results obtained in this study.

DOI： 10.11491/apcche.2004.0.261.0

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Language：Japanese   Publisher：The Society of Powder Technology, Japan  

DOI： 10.4164/sptj.40.831

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The effect of chemical reaction rate on the generation of titania nanoparticles by chemical vapor deposition using two different precursors was investigated by FTIR, XRD, and microscopy. The size of the primary particle exhibited a minimum with increasing reactor temperature. At lower reaction temperatures, the continuous and gradual formation of titania monomers occurred followed by coagulation and/or surface reaction on the existing particles. In addition, unreacted precursor condensed at the reactor exit. As the reaction temperature increased, the rate of monomer production increased, the dominant characteristics of particle growth were coagulation and sintering. The reactor temperature where the minimum primary particle diameter was produced was different for the two precursors due to differences in chemical reaction rates. Phase composition as well as the primary particle diameter of product titania were affected by the chemical reaction rate. Particle-laden reactor wall enhanced the precursor conversion at low reactor temperatures, where surface reactions compete effectively with gas-phase precursor conversion. (C) 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/S0009-2509(03)00213-6

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Non-agglomerated spherical silicon, titanium and zirconium oxide nanoparticles were prepared using an electrospray assisted chemical vapor deposition (ES-CVD) process. Metal alkoxides in conjunction with an electrospray method were used to introduce charged precursors into a CVD reactor. The ions are produced during evaporation of the charged droplets, and they probably act as seed nuclei (i.e., ion-induced nucleation) and/or, they are attached to the produced particles. The experimental results were compared with those obtained using a conventional evaporation CVD method. The particles generated using the conventional evaporation method were agglomerated to a considerable extent irregardless of the type of particle. Whereas, at the same conditions, high concentrations of non-agglomerated nanoparticles having diameters in the range of 10-40 nm were obtained using the ES-CVD method. This appears to be due to the charging effects of the generated particles, that is, the electrostatic dispersion of unipolarly charged particles. The size of the non-agglomerated particles in the ES-CVD method was reduced as the results of the decease in the concentration of precursors introduced by electrospray. (C) 2003 Elsevier Ltd. All rights reserved.

DOI： 10.1016/S0021-8502(03)00053-3

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Language：English   Publishing type：Doctoral thesis  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Morphological changes of agglomerates consisting of nanometer primary gold particles were studied experimentally and theoretically. Gold aerosol nanoparticles were produced using the evaporation/condensation method, and the change in agglomerate size by reheating was examined experimentally using a tandem DMA setup. Numerical calculations, based on two extreme mechanisms to reshape agglomerates, i.e., subsequent coalescence of primary particles and subsequent rearrangement of primary particles, were carried out. By comparison with the experimental results, the sintering time and the rate constant of restructuring were obtained. Using these values, the change in particle size for different generation conditions could be calculated. The change in morphology of agglomerates can be explained from the comparison of the experimental results with the theoretical calculations: agglomerates with smaller primary particles will compact mainly by the subsequent coalescence of primary particles, while agglomerates with larger primary particles will compact mainly by a rearrangement of primary particles. (C) 2002 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0021-8502(02)00058-7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS INC  

In the manufacturing of nanometer-sized material particlulates by aerosol gas-to-particle conversion processes, it is important to analyze how the gas-phase chemical reaction, nucleation, agglomeration, and sintering rates control the size distribution and morphology of particles. In this study, titania particles were produced experimentally by the thermal decomposition of titanium tetraisopropoxide (TTIP) and oxidation of titanium tetrachloride (TiCl4) using a laminar ? ow aerosol reactor. The effect of reaction temperature on the size and morphology of the generated particles was investigated under various conditions. The size distributions of agglomerates were measured using a DMA/CNC system. The size distributions of primary particles were measured using TEM pictures of the agglomerates sampled by a thermophoretic aerosol sampler. In order to model the growth of both agglomerates and primary particles simultaneously, a two-dimensional discrete-sectional representation of the size distribution was employed, solving the aerosol general dynamic equation for chemical reaction, agglomeration, and sintering. Qualitative agreement between the experimentally observed results and the simulation are satisfactory for the large variations in reactor temperature explored.

DOI： 10.1080/02786820126857

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Achieving a uniform film thickness profile over a substrate has been difficult in CVD-Al2O3 coating processes. Although this problem can be solved by H2S-doping to the source gas mixture, AlCl3/CO2/H-2, the role of H2S in the mechanisms of the CVD coating have not been clarified. In this study, the effects of H2S-doping on the improvement of the uniformity of a coated layer is studied, focusing on the particles generated in the gas phase. it is found in the measurement of gasborne particles that the number concentration of particles larger than 200 nm in diameter is reduced dramatically by the H2S-doping. The concentration is over 10(8) particles/m(3) when no H2S is doped, while it is less than 10(6) particles/m(3) at 0.20% doping. The improvement of the coating by H2S-doping is concluded to be caused by a size reduction of particulate matters of the Al2O3 precursors that leads to an increase of the diffusivity.

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC CHEMICAL ENG JAPAN  

Two different ionization CVD reactors where the surface corona discharger is used as the ion source, are developed and film preparation by a tetraethoxysilane/ozone atmospheric pressure CVD is arrempted. In the close-type reactor where the discharger is close to the substrate, discontinuous films where thickness changes alternately and extremely from zero to a few microns in the distance of millimeter order are formed probably due to the charge of ions accumulated on the surface of Si wafer. In the separate-type reactor where the discharger is distant from the substrate, films with uniform thickness are formed, and the film growth rate is 1.3-1.5 times higher than that without discharge. The separate-type reactor prepared films with strong flow-like shape under conditions where films without flow-like shape are formed in the common reactor. Nanometer-sized particles of 20-100 nm in diameter, which have been generally generated without discharge, are not detected in the ionization CVD reactor.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

A chemical vapor deposition (CVD) method, called ionization CVD, in which ionized source molecules were deposited on a substrate by Coulombic force, was developed to control gas-phase reaction and film morphology. This method was applied to the tetraethylorthosilicate (TEOS)/ozone-atmospheric pressure chemical vapor deposition process by using the surface corona discharge. TEOS/O-3 films deposited on SiN and SiO2 films by this CVD method showed good properties for the flow shape, the gap filling and the surface morphology. In Fourier-transform infrared spectra of gas-phase intermediates collected in the vapor condenser, the intensity of the absorption peak at 600 cm-1 was different between ionized intermediates and nonionized intermediates. (C) 1999 American Institute of Physics. [S0003-6951(99)04639-2].

DOI： 10.1063/1.124889

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：E D P SCIENCES  

The role of H2S in the mechanism of CVD-Al2O3 coating was investigated by measuring particles suspended in the gas phase with an optical particle counter. H2S doping of the CVD-Al2O3 process improves the homogeneity of thickness and growth rate of the Al2O3 layer. The number of particles produced in the reactor whose size was larger than 200 nm was dramatically reduced by H2S doping. The effect of H2S doping appears to be a reduction of the size of Al2O3 particles present in the reactor. These smaller particles have a greater mobility, which will allow them to arrive at the surface, regardless of the shape or arrangement of the substrate inside the reactor.

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Language：Japanese   Publishing type：Book review, literature introduction, etc.  

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Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：The Society of Powder Technology, Japan  

<p>Unused thermal energy such as waste thermal energy from industrial processes is due to low temperature level and unstable output. For the effective utilization of the unused thermal energy, thermal energy storage, in particular chemical heat storage is a key technology. In this review, a novel adsorption heat pump, which is one of the chemical heat storage, is introduced. This system adopts a direct heat exchange method to the adsorption heat pump to increase heat transfer rate between adsorbent and heat transfer fluid. Basic operation and the methods to improve the efficiency of the heat pump system are explained.</p>

DOI： 10.4164/sptj.53.442

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Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

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Language：English   Publishing type：Internal/External technical report, pre-print, etc.   Publisher：International Institute of Refrigeration  

Enhancement of generation of high-temperature steam using a novel adsorption heat pump is investigated. In this study, enhancement of the preheating process by the use of thermal energy storage material was investigated. The effect of the heat capacity of adsorbent on the mass of steam generated was theoretically investigated. As a result, while the mass of water vapor adsorbed during the preheating was increased with the heat capacity of the adsorbent, the temperature after the preheating process decreased. It was found that there was the maximum value in the mass of steam generated. In the experiment, an additive was inserted as the thermal energy storage material to increase the heat capacity of adsorbent. When the overall heat capacity of the packed bed of the adsorbent was increased by 18% by using the additive, the mass of steam generated per unit mass of the adsorbent was increased by 25%.

DOI： 10.18462/iir.icr.2015.0090

Scopus

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Language：English   Publishing type：Internal/External technical report, pre-print, etc.  

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Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

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Language：Japanese  

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：The Japan Society of Mechanical Engineers  

To conventionally extend heat transfer area in shell-and-tube heat exchangers, a method is proposed where sheet materials with high thermal conductivities are stretched among tubes. The numerical simulations are carried out to predict the performance of heat exchanger with or without the sheets. As a result, it is found that thermal contact resistances between the sheet and tubes rather than thickness and thermal conductivity of the sheet influence overall heat transfer coefficient. In the experiments, the carbon fibers clothes (27 W m^-1 K^-1) are pass zigzag though the tubes whose pitch is 20 mm. The heat transfer rate between hot water flowing in the tube side and air in the shell side are measured. No substantial improvement of heat transfer is unfortunately observed experimentally due to contact thermal resistance. The method proposed in this study conclusively has a potential that the heat transfer rate improves no less than a few ten percents.

DOI： 10.1299/jee.6.400

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Language：Japanese  

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Language：English   Publisher：Kyushu University G-COE program "Novel Carbon Resource Sciences" secretariat  

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Other Link： http://hdl.handle.net/2324/18392

Language：Japanese   Publisher：The Heat Transfer Society of Japan  

排ガスからの廃熱回収効率の改善策の一つとして，伝熱面拡大策を提案する．放射伝熱の影響する高温度域で伝熱管群内に張ったフィンの伝熱・流動特性の関係を数値的に検討した．パラメータとして，胴側 Reynolds数を5000～10000で変化させた際の伝熱促進の影響について検討した．流体として赤外活性気体のCO&lt;SUB&gt;2&lt;/SUB&gt;を想定し,伝熱管代表径を変化させた際の放射伝熱の寄与による伝熱促進の影響を確認した．また，フィンと伝熱管表面との接触抵抗を考慮することで実際のフィンの有効性についても検討した．

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Language：English   Publisher：Kyushu University G-COE program "Novel Carbon Resource Sciences" secretariat  

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Other Link： http://hdl.handle.net/2324/18393

Language：Japanese  

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2009.0.455.0

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DOI： 10.11368/htsj1999.45.192_46

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

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Language：Japanese   Publisher：公益社団法人 化学工学会  

DOI： 10.11491/scej.2005.0.702.0

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

Thermal characteristics of laboratory- and practical-scale latent heat thermal energy storage tanks are investigated experimentally and theoretically. Commercial paraffin wax as the thermal energy storage material is packed in the tanks. Cloths made of high conductive carbon fibers are installed in the tanks to enhance the heat transfer rate in the tanks. Experimental results show that the thermal characteristics of the tanks are improved with increasing volume fraction of carbon fibers. A numerical model is developed to predict the thermal characteristics of the tanks. Optimum volume fractions of carbon fibers added in the tanks is numerically discussed.

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Language：Japanese  

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Language：Japanese  

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Language：Japanese   Publisher：The Society of Powder Technology, Japan  

DOI： 10.4164/sptj.39.670

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Other Link： https://jlc.jst.go.jp/DN/JALC/00158864073?from=CiNii

Language：Japanese   Publisher：工業調査会  

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Language：Japanese  

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Language：Japanese   Publisher：粉体工学会  

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Language：Japanese   Publisher：The Society of Inorganic Materials, Japan  

DOI： 10.11451/mukimate2000.8.409

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Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

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Language：Japanese   Publisher：Japan Association of Aerosol Science and Technology  

DOI： 10.11203/jar.15.226

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Language：English   Publisher：Elsevier Ltd  

DOI： 10.1016/S0021-8502(98)90636-X

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Event date： 2023.9.11 - 2023.9.13

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