記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Heat and Mass Transfer  

This study was focused on the evaluation of the adsorption kinetics of water vapor onto silica-gel with and without an acoustic field, in an objective to reveal the enhancement mechanisms of water vapor adsorption by an acoustic wave. Adsorption uptake curves of water vapor from humidified air onto the silica-gel with and without acoustic field were measured at room temperature under various conditions, after which the adsorption kinetic parameters (fluid film mass transfer coefficient and intraparticle diffusivity) were determined from the uptake curves with the aid of numerical calculations. The results demonstrated that the acoustic field exhibited no effect on the intraparticle diffusion, because the fluid film mass transfer was the rate-limiting step under the condition of this study. In contrast, the fluid film mass transfer was enhanced by the velocity amplitude of the acoustic field. However, the diminished mass transfer was also observed in some cases. For the enhancement and diminution of adsorption rate by the acoustic wave, it was suggested that the ratio of the oscillation flow (U) to the steady flow (u), U’ = U/u, was an important factor. Moreover, the enhanced adsorption kinetics was observed under the conditions of U’ > 2, whereas the adsorption rate was diminished or invariant under the condition of U’ < 2. This would be understood from the viewpoint of the thinning and thickening of fluid film by the oscillation flow caused by the acoustic wave. Even when the direction of the oscillation flow is countercurrent to the steady flow, the thinning of fluid film by the oscillation flow is still possible under U’ = U/u > 2.

DOI： 10.1016/j.ijheatmasstransfer.2019.119088

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Chemical Engineering of Japan  

In this study, the hydrothermal conversion of FAU-type zeolites using an aqueous ammonia solution was investigated to understand the solid-phase transformation mechanism of the selective synthesis of target zeolites. In addition, the CO2/N2 separation ability of prepared materials was estimated from single-component adsorption isotherms by the ideal adsorbed solution theory. ABW and ANA-type zeolites were successfully synthesized from the FAU-type zeolites such as Li-LSX and Na-X, respectively, by a hydrothermal treatment using an aqueous ammonia solution. Li-LSX was completely converted into ABW by treating at a temperature above 150°C for 24 h, and ANA was mainly produced from Na-X at 250°C after treating for over 72 h. The pellet shape of the raw zeolites was maintained even after the hydrothermal treatment. Considering the transformation mechanisms, the results suggest that the transformation of the zeolite topology was caused by the ion exchange between the counter cation of the zeolite and ammonium ion in the solvent and the cation structure-directing effect under hydrothermal conditions. It can be concluded that the counter cations of the raw zeolites played an important role in the structural transformation. The simple synthesis method presented in this study enables the conversion of FAU-type zeolites, particularly X-type zeolite, into other types of zeolites without using strong bases, such as alkali hydroxides. In terms of the CO2/N2 separation ability, CO2/N2 selectivity for post-combustion CO2 capture conditions drastically increased upon the hydrothermal treatment. In particular, the ABW-type zeolite exhibited extremely high CO2/N2 selectivity over 10000.

DOI： 10.1252/jcej.19we149

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Surface Science  

Nitrogen-doped porous carbons were prepared via chemical activation of chitosan using alkali-metal carbonates (Na2CO3, K2CO3, Rb2CO3, and Cs2CO3), and the water adsorption isotherms of prepared carbons were measured to estimate the performance of the carbons in adsorption heat pump/desiccant cooling. Pre-doping of an alkali carbonate activator into the chitosan precursor resulted in a highly developed micropore structure and the introduction of macropores. The macropore structure clearly depended on the alkali carbonate activator. Na2CO3 resulted in two-dimensional macropores because of the hard-template effect, whereas the other alkali carbonate activators resulted in three-dimensional macropores with different cell sizes. A density functional theory calculation study based on X-ray photoelectron spectroscopy analyses of nitrogen-doped activated carbons indicated that pyridinic (pyridine, pyridone, and pyridine N-oxide), amide, and quaternary N groups might be effective for low-pressure water adsorption. Although the water adsorption capacities of the prepared carbons at P/P0 > 0.5 increased with increasing micropore volume, those at the low-pressure region (P/P0 < 0.1) were dependent on the surface density of nitrogen or oxygen functional groups. In addition, the shape of water isotherms preferable for adsorption heat pump/desiccant cooling was observed for the carbons with an appropriate surface density of nitrogen functional groups.

DOI： 10.1016/j.apsusc.2019.06.267

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記述言語：日本語   出版者・発行元：公益社団法人 日本冷凍空調学会  

&lt;p&gt;本研究では音波が吸着促進を引き起こす現象について，音波の周波数が与える影響について実験的に測定するとともに，吸着促進を起こす条件について考察した．3種類の共振モードで音波を印加した結果，速度振幅に対する吸着促進効果の勾配および効果が発生する下限値（臨界速度振幅）に周波数の影響が表れることを見出した．一様流に音波による振動流が合わさった脈動流の実質的な変位振幅がある値以上になると吸着促進効果を生じるとの仮説に基づいて考察した結果，臨界速振幅は周波数の一次式で表されることを導いた．また，その理論式は実験結果とも整合していることから，この仮説が吸着促進現象に有効であることを明らかにした．&lt;/p&gt;

J-GLOBAL

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Sustainable Chemistry and Engineering  

Tetraethylenepentamine (TEPA) and its derivatives were used to functionalize mesocellular silica foam (MSU-F) supports by wet impregnation for utilization as solid sorbents for CO2 capture. TEPA derivatives were synthesized by introducing various substituents into the amino groups of TEPA. The CO2 adsorption and desorption properties of the solid sorbents were evaluated to assess the effects of substituent introduction. TEPA derivatives with bulky alkyl groups such as 3-pentyl (Pe) substituents drastically enhanced the adsorption and regeneration performance of the solid sorbents, while the introduction of hydroxyalkyl substituents had a negative effect on the CO2 adsorption capacity. The mechanisms governing these effects are discussed in terms of CO2 affinity and diffusivity, depending on the introduced functionality. For a simulant flue gas of 14% CO2, 5% O2, 4% H2O, and balance N2 at 40 °C, MSU-F-supported Pe-TEPA showed a working capacity higher than 4 mmol CO2/g by inert-gas sweeping regeneration at 60 °C with excellent cyclic stability. The results demonstrate that the regeneration performance is greatly improved by chemical modification of the amino functional groups of amine-impregnated solid sorbents. This approach is promising for developing low-energy and low-temperature CO2 capture technologies.

DOI： 10.1021/acssuschemeng.9b01064

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Fuel  

The adsorptive removal of sulfur-containing compounds such as thiophene derivatives from transportation fuels has received extensive attention because of its economic and environmental advantages compared to the hydrodesulfurization process. In our previous study, we suggested that the adsorption sites for benzothiophene and naphthalene on the silica surface consist of different types of silanol groups, and the removal of vicinal silanols from the silica surface should enable silica materials to adsorb benzothiophene selectively. In this study, an attempt is made to prove this hypothesis for the development of novel desulfurization sorbents. Heat treatment of silica gel was performed at different temperatures to remove vicinal silanol groups, and the adsorption capacities of benzothiophene and naphthalene were evaluated. The amount of naphthalene adsorbed on heat-treated silica gel decreased with increasing heat-treatment temperature, whereas the amount of benzothiophene adsorbed on silica gel treated at 873 and 1073 K showed only a slight decrease. Considering the heat treatment might lead to the removal of vicinal silanols due to dehydration of surface silanols, the results indicate that vicinal silanol groups were selective adsorption sites for naphthalene. Moreover, for binary-component systems, the adsorption capacities of benzothiophene and naphthalene were almost identical because of multilayer adsorption of naphthalene on adsorbed benzothiophene, and the adsorption capacities of benzothiophene for single- and binary-component systems were also identical. This suggests that the heat treatment of silica enables the selective removal of benzothiophene.

DOI： 10.1016/j.fuel.2017.11.070

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Fuel  

Chemical modification of the amino functional groups of amine-impregnated solid sorbents is an effective strategy for drastically improving the regeneration performance for CO2 capture. In this study, isopropyl groups were introduced into tetraethylenepentamine (TEPA) to obtain N-(isopropyl)-TEPA (IP-TEPA), which was impregnated in mesocellular silica foam (MSU-F). The obtained solid sorbent enabled low-temperature regeneration with a low regeneration energy. To clarify the role of the IP groups, experimental and computational methods were used to compare the IP-TEPA/MSU-F sorbent with TEPA/MSU-F in terms of CO2 working capacity, reaction product stability, self-diffusion coefficient, 13C spin–lattice relaxation time, and CO2 capture performance in steam-aided vacuum swing adsorption.

DOI： 10.1016/j.fuel.2017.10.108

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出版者・発行元：GHGT 2018 - 14th International Conference on Greenhouse Gas Control Technologies  

The Research Institute of Innovative Technology for the Earth (RITE) has been developing advanced CO2 technologies, specifically high performance solid sorbents to capture CO2 from coal-fired power generation plants. RITE has developed a novel solid sorbent that incorporated the amine functionality with regards to CO2 absorption on a porous silica support. The RITE solid sorbent is based on a novel polyamine that provides low temperature regeneration of around 60°C. The sorbent is shown to exhibit a regeneration energy of 1.5 GJ/ton-CO2 along with a high CO2 recovery ratio, which reduces the overall post-combustion costs of CO2 capture. Currently, the bench scale test capturing ~5 ton-CO2/day is underway by the Kawasaki Heavy Industries (KHI) moving bed system using the RITE solid sorbent.

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Transport in Porous Media  

This study focuses on the development of a novel analysis technique for determining the intraparticle diffusivity (DS) and fluid film mass transfer coefficient (kF) from a concentration history curve of a recycle fixed-bed reactor without using the linear driving force approximation and empirical equations for the estimation of kF. The recycle fixed-bed method requires lesser amounts of working fluid for experiment purposes, which is an advantage over the usual fixed-bed method. Based on the characterization results of the concentration history curves, simulated by rigorous numerical calculations, a novel analysis technique was established. The DS value can be determined from the experimentally obtained time at which the concentration of the curve is minimal (tCmin). The kF value can be determined from the DS value and Biot number (Bi), which can be estimated from the experimental ratio of the maximum concentration to the minimum concentration (cmax/ cmin). The DS and kF values of phenol adsorption on an activated carbon material were determined experimentally using the proposed analysis method. This method enables the determination of reliable adsorption kinetic parameters through a simple and economical experiment. However, appropriate experimental data must be acquired under regulated experimental conditions, especially in the case of fluctuation of the concentration history curve.

DOI： 10.1007/s11242-017-0925-x

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Engineering Journal  

A novel amine-based solid sorbent was prepared for CO2 capture, and the CO2 adsorption characteristics were evaluated for simulated flue gas. Furthermore, CO2 capture tests using a lab-scale three-column fixed-bed system were performed. A novel amine compound was synthesized by attaching hindered functional groups to the terminal primary amino groups of a polyamine, followed by impregnation into pelletized mesoporous MSU-F silica. This novel amine-impregnated solid sorbent overcame the problem of limited CO2 diffusion and exhibited extremely high regenerability even at low temperatures. Lab-scale CO2 capture tests suggested that operation conditions such as temperature, cycle time, rinsing time, flow rate, and regeneration method directly affected CO2 capture performance. In particular, direct low-temperature steam stripping desorption drastically enhanced CO2 capture performance. Steam-aided vacuum swing adsorption (SA-VSA) process was feasible for our amine-based solid sorbent and enabled the recovery of CO2 with high purity (>98%) and recovery rate (>93%). The regeneration heat calculated from the amount of recovered CO2 and the amount of supplied steam was considerably lower (1.47 GJ/t-CO2) than that of liquid amine solvents and other amine-based solid sorbents.

DOI： 10.1016/j.cej.2016.08.071

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1177/0263617416674013

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記述言語：日本語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Energy Procedia  

A new synthetic polyamine was found as a suitable compound for amine-impregnated solid sorbent through screening of amine compounds with the aid of density functional theory calculations. CO2 capture performance of the sorbent was evaluated on a lab-scale CO2 capture system. The solid sorbent was excellently regenerable even at low temperature condition. Then, Bench-scale demonstration will be started on current project, using the sorbent developed by Research Institute of Innovative Technology for the Earth (RITE) and moving bed system of Kawasaki Heavy Industries, Ltd (KHI).

DOI： 10.1016/j.egypro.2017.03.1371

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.serj.2016.09.001

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Fuel  

The adsorptive removal of sulfur-containing compounds such as thiophene and dibenzothiophene derivatives from transportation fuels has received extensive attention because of the economical and environmental advantages of adsorptive removal compared to the hydrodesulfurization process. Metal-ion-exchanged zeolites have been known to exhibit high desulfurization performance. However, zeolites induce side reactions because of their strong acidity. Accordingly, silica-based adsorbents showing lower acidity have potential for the desulfurization adsorbent. In this study, to facilitate the development of efficient desulfurization adsorbents, the mechanisms of benzothiophene and naphthalene adsorption onto silica surface were investigated using density functional theory (DFT) in conjunction with experimental approaches. Both the computational and the experimental results suggested that the sites at which benzothiophene and naphthalene adsorb onto silica gel are different types of silanol groups. The adsorption sites of benzothiophene at the initial stage were vicinal-type and/or geminal-type silanols and the final adsorption sites were isolated-type silanols. In addition, the results of DFT calculations suggest that multilayer adsorption might occur. In contrast, the adsorption sites of naphthalene at the initial stage were vicinal-type silanols. Afterward, multilayer adsorption through a T-shape interaction might occur successively on the silica surface.

DOI： 10.1016/j.fuel.2015.10.013

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

Highly porous nitrogen-doped activated carbons (NACs) were prepared by the chemical activation of chitosan using alkali carbonates. The NACs exhibited extremely high CO2 capacities of 1.6 mmol g-1 (15 kPa) and 4.9 mmol g-1 (100 kPa) at 25 °C. Nitrogen atoms doped into carbon frameworks clearly enhanced CO2 adsorption at low partial pressures.

DOI： 10.1039/c5cc06934c

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Separation Science and Technology (Philadelphia)  

Mesocellular silica foam (MSU-F) supports were functionalized via wet impregnation with various amine and alcohol compounds for use as high-capacity adsorbents for CO2 separation. The effect of the amino, hydroxyl, and ether functional groups in the impregnating mixture on the CO2 adsorption capacity was investigated. Chemical adsorption was controlled by the composition of the compounds, and the blending effect on the adsorption performance was dependent on the temperature. MSU-F (30 wt.%) impregnated with a mixture of tetraethylenepentamine (40 wt.%) and aminoethylethanolamine (30 wt.%) showed a high adsorption capacity of 5.4 mmol/g at 333 K for 15 kPa CO2.

DOI： 10.1080/01496395.2015.1085416

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Microporous and Mesoporous Materials  

Amine-impregnated mesoporous silica materials were prepared using surface-modified silica supports for CO<inf>2</inf> capture, and the effects of the surface chemical structure of the support on the CO<inf>2</inf> adsorption performance of surface-modified silica-supported amines were investigated systematically. The thermal stability and CO<inf>2</inf> adsorption characteristics of amine-impregnated materials were determined experimentally. The surface modification of mesoporous silicas by particular functional groups leads to increases in thermal stability of loaded amine and CO<inf>2</inf> adsorption capacity. In particular, the CO<inf>2</inf> adsorption performance in the presence of water vapor was remarkably enhanced by surface modification of the silica support. Computational analyses indicated that increases in the thermal stability of loaded amine and CO<inf>2</inf> adsorption capacity were due to the hydrophilicity and electron donativity (nucleophilicity) of introduced functional groups. Compared to non-modified support, CO<inf>2</inf> adsorption capacities for surface-modified silica supported amines were increased up to 118% in the absence of water vapor and 182% in the presence of water vapor. It is suggested that the surface structure of supports for amine-impregnated mesoporous silica materials plays an important role in CO<inf>2</inf> adsorption performance.

DOI： 10.1016/j.micromeso.2015.05.037

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Energy and Fuels  

Polyethylenimine-functionalized porous chitosan (PEI-CS) beads were prepared and their CO2 adsorption performance was evaluated. The CO2 adsorption capacity of PEI-CS was dependent upon both the amine content and surface area of the functionalized beads. PEI-CS showed a CO2 adsorption capacity of 2.3 mmol/g at 313 K and 15 kPa of CO2 in the absence of water vapor that considerably increased to 3.6 mmol/g in the presence of water vapor. To rationalize this phenomenon, the CO2 adsorption mechanisms in the absence and presence of water vapor were investigated by diffuse reflectance infrared Fourier transform spectroscopy. The results indicated that the mechanism of CO2 adsorption onto PEI-CS, in both the absence and presence of water vapor, involved the formation of carbamate. Therefore, the higher CO2 adsorption capacity in the presence of water vapor was attributed to the increased accessibility to amino groups of PEI-CS, owing to swelling of the polyethylenimine chain and/or chitosan framework upon adsorption of water. The herein reported chitosan-based material displays high CO2 adsorption capacity as well as excellent regenerability and, thereby, shows potential as an adsorbent for CO2 capture.

DOI： 10.1021/ef500975g

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Transport in Porous Media  

To design and use adsorbers, adsorption kinetic properties must be determined. Several experimental methods and many analysis techniques for determining intraparticle diffusivity (DP) have been proposed for single- and multi-component adsorption systems. However, determining DP values from experimental data of multi-component adsorption systems requires trial and error curve-fitting of experimental with theoretical curves. Furthermore, adsorption calculations of multi-component systems are complicated. For example, displacement adsorption, which causes concentration overshoot phenomena, is troublesome when analyzing experimental data. This report focuses on a simple alternative analysis technique for determining the DP values of each component from binary-component adsorption uptake curves. This new analysis method was established for binary-component and pore diffusion-controlling adsorption systems, and enables to analyze binary-component uptake curves by use of single-component uptake curves. Treatment of the equilibrium relation is significant when calculating single-component adsorption uptake curves. This method is useful to analyze experimental results, even if the results show concentration overshoot. © 2014 Springer Science+Business Media Dordrecht.

DOI： 10.1007/s11242-014-0278-7

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記述言語：日本語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Energy Procedia  

Based on insight into the amine-CO2 chemistry from quantum chemical calculations, we designed and developed energy efficient amine solid sorbents for CO2 capture. Novel amine absorbent were synthesized and used for the wet impregnation into mesoporous materials. The blending effect on the CO2 capture was also investigated for various amine absorbents. The developed amine solid sorbents showed high performance in terms of adsorption capacity, desorption efficiency, and regeneration energy.

DOI： 10.1016/j.egypro.2014.11.255

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry Letters  

DOI： 10.1246/cl.130675

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/ceat.201200319

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The mass transfer zone (MTZ) method using the linear driving force (LDF)<br />
approximation is the most common and frequently used technique for the analysis of adsorption kinetics from a fIxed-bed breakthrough curve and for adsorptive process design. However, the adsorption kinetics obtained by the MTZ method includes approximations and estimation errors. This report describes a new analytical method for determining the intraparticle diffusivity (Ds) and the fluid-fIlm mass transfer coeffIcient (kF) from an experimental breakthrough curve without using the LDF approximation and empirical correlations for estimating kF.The proposed method has the advantage of less trial and error on the curve-fItting process and helps better determine Ds and kF. The estimation procedure of the Biot number that represents the ratio of Ds to kp is the key of this method. The values of Ds and kp for the adsorption of phenols onto activated carbon were determined from experimental breakthrough curves using the new analytical method. The results indicate that the method presented in this study yields reliable values.

DOI： 10.1 002/ceat.20120031

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cej.2011.07.035

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Accurate physical and chemical properties of adsorbents are required for the efficient design of fixed bed adsorbers. The bed<br />
void and particle void are significant physical properties. One of the experimentally determination technique for the bed void is a<br />
breakthrough curve method. In the present paper, experimental conditions for determining the bed void from breakthrough curve were<br />
investigated because complex conditions are required. The values of bed void were determined from theoretical elution curve at the<br />
point of c/c0 = 0.5 under the condition of negligible amount adsorbed. The bed void value determined from elution curve was clearly<br />
affected by particle void and fluid velocity, and regarded as “apparent” bed void values. For large porosity particles, it was difficult to<br />
determine the true bed void value due to the effect of penetration into macro pores. Then, the bed void fraction can be determined safely<br />
from breakthrough curve when particles possessing small particle void are used.

記述言語：日本語  

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1252/jcej.10we295

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cej.2010.04.012

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.seppur.2007.08.019

Web of Science

記述言語：日本語  

This study focuses on the phenomenon that the adsorption speed is improved by acoustic wave. An experimental study reported the velocity amplitude of acoustic wave is closely related to the adsorption acceleration. The purpose of this study is to elucidate the adsorption acceleration phenomenon by CFD analysis. A model representing a packed bed was created and analyzed. A result showed that the adsorption of a silica gel particle is faster on the upstream side than on the downstream side in uniform flow, which indicates good agreement with the calculation of Mcbain equation. In addition, adsorption analysis with some oscillatory flows reproduced the adsorption enhancement similar to the experimental results. It suggests that the calculation by CFD can estimate the behavior of adsorption in an oscillating flow.

記述言語：日本語  

J-GLOBAL

記述言語：日本語  

J-GLOBAL

記述言語：日本語  

J-GLOBAL

記述言語：日本語  

記述言語：日本語  

J-GLOBAL

記述言語：日本語   出版者・発行元：技術情報協会  

記述言語：日本語   出版者・発行元：一般社団法人 日本エネルギー学会  

Energy analysis was conducted to precisely evaluate performance of CO_2 capture with a RITE-developed solid sorbent from a coal-fired power plant. The solid sorbent had an advantage of low regeneration energy consumption and the energy efficiency of a power plant with CO_2 capture was estimated to improve by about 2% when the solid sorbent was used in place of a latest liquid amine solvent. The solid sorbent also had a high regeneration performance in low temperature of 60 ℃. That is, there is a high possibility that a low-temperature waste heat was easily used for regeneration of the solid sorbent.

記述言語：日本語   出版者・発行元：公益社団法人 化学工学会