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Evaluation of SrBr₂ Hydration Reaction Rate with Repeated Cycling

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Journal of Materials Science and Chemical Engineering 2022年第2期10卷 53-61页

作者： takehiro esaki Yuichi Sugai Department of Earth Resources Engineering Kyushu University Fukuoka Japan

In this study, we evaluated the SrBr2 hydration reaction rate on repeated cycling. It was estimated that hydrated SrBr2 particles were expanded by hydration and condensed to form secondary particles;thus, the hydration reaction was reduced by repeated cycles. Using volumetric methods, we examined the effect of repetition on the reaction rate for 900 cycles during hydration and dehydration and analyzed the reaction rate using the unreacted core-shell model. From the experimental and calculated results, we confirmed that reaction rate decreased and the sample particles formed secondary particles after 900 repeated cycles. By analyzing the unreacted core-shell model, we found that the coefficient of H2O diffusion in the particles exponentially decreased with increasing repeated cycles. The value of the diffusion coefficient after 900 cycles was five times lower than that of the first cycle. To achieve stable repeated hydration cycles, technology to control the formation of secondary particles must be investigated.

关键词： SrBr2 Hydration Repetition Cycle The Coefficient of Particle Diffusion

Analysis of CO2Pressure Swing Adsorption Simulation by Considering the Transport Phenomena in the Adsorber

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Journal of Materials Science and Chemical Engineering 2021年第3期9卷 39-54页

作者： takehiro esaki Hideaki Kuronuma Noriyuki Kobayashi Department of Chemical Engineering Faculty of Engineering Fukuoka University Fukuoka Japan Chemical systems engineering Graduate School of Engineering Nagoya University Aichi Japan

This study focused on CO2 separation technology with adsorption. This paper describes the analysis carried out by a CO2 pressure swing adsorption simulation to scale up the absorber. An unsteady one-dimensional balance model was constructed by considering the material, energy, and momentum. In the CO2 breakthrough test, the beginning time and CO2 concentration at outlet of CO2 breakthrough in the calculation were almost equivalent to that of experiment results. The correlation consistency of the calculation results with the analysis model and the experimental results obtained by a bench scale experiment was evaluated. The transport phenomena in the adsorber were investigated at the adsorption, rinse, and desorption steps according to the calculation results. The starting time of CO2 breakthrough obtained by the analysis is equal to that obtained by the adsorption breakthrough experiment. This confirms that the CO2 adsorption, and the temperature and velocity distribution in the adsorber, change as a function of the adsorption, rinse, and desorption steps, respectively. Additionally, the CO2 concentration of the captured gas and the amount of CO2 quantity were 93.4% per day and 2.9 ton/day, respectively. These values are equal to those obtained by the bench scale experiment.

关键词： Carbon Dioxide Separation Pressure Swing Adsorption Numerical Analysis

Evaluation of the Characteristic of Adsorption in a Double-Effect Adsorption Chiller with FAM-Z01

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Journal of Materials Science and Chemical Engineering 2016年第10期4卷 8-19页

作者： takehiro esaki Noriyuki Kobayashi Takayuki Matsuda Department of Chemical Engineering Nagoya University Nagoya Japan

Here, we propose a double-effect adsorption chiller with a zeolite adsorbent (FAM-Z01) for utilization of waste heat. The FAM-Z01 adsorbent has the potential to recover waste heat in low temperatures ranging from 353 to 333 K and shows good potential in the adsorption chiller in terms of the high cooling output. A double-effect adsorption chiller could provide a higher Coefficient Of Performance (COP) than that of a single-effect chiller. In this paper, we developed a measuring method for the amount of adsorption in the first and second adsorber in a double-effect adsorption chiller and measured the adsorption and desorption rate based on the volumetric method. We calculated the COP of the adsorption chiller with the quantity of adsorbent obtained in the experiment. In the experiments, the quantity of adsorbent in the first adsorber was 0.14 g-H2O/g-Ads at the pressure 20 kPa and a desorption temperature over 100℃. The amount of adsorbent in the second adsorber was equal to that of the first adsorber. By analyzing the COP with the experimental results, the COP value was calculated to be over 1.0 (–) at any desorption temperature. The COP of the double-effect cycle was higher than that of single-effect cycle.

关键词： Adsorption Chiller Double-Effect FAM-Z01 Coefficient of Performance

Evaluation of Carbon Dioxide Absorption Characteristics Lithium Ortho-Silicate in Chemical Heat Storage

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Journal of Materials Science and Chemical Engineering 2017年第4期5卷 56-63页

作者： takehiro esaki Daichi Iwase Noriyuki Kobayashi Department of Chemical Engineering Nagoya University Nagoya Japan

We report the development of technology that may contribute to a reduction in greenhouse gas emissions and improve the energy efficiency of the CO2 capture process. Lithium ortho-silicate is a suitable solid sorbent for capturing CO2. This reversible chemical reaction is also applicable to chemical heat storage. The absorption reaction characteristics of lithium ortho-silicate were studied by a thermogravimetric method and a volumetric method that demonstrated the influence of heat and mass transfer limitations in a packed bed designed to be as small as possible. We developed a method for measuring the absorption reaction characteristics in the experiments. In the experiments, a constant conversion fraction of 60% was observed. The reaction system was stable to repetition. The CO2 absorption rate depends on the CO2 pressure and reactor temperature. The absorption rate was determined at several reactor temperatures when the conversion fraction was 0.3. In this study, the maximum absorption rate was obtained at 670oC. It was demonstrated that lithium ortho-silicate is suitable for use in a chemical heat storage system.

关键词： CO2 Capture Chemical Heat Storage Lithium Ortho-Silicate Absorption Rate

Characteristics of Absorption Equilibrium with HFC-134a and an Ionic Liquid Pair

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Journal of Materials Science and Chemical Engineering 2019年第3期7卷 65-78页

作者： takehiro esaki Noriyuki Kobayashi Hiroki Uchiyama Yousuke Matsukuma Department of Chemical Engineering Faculty of Engineering Fukuoka University Fukuoka Japan Department of Chemical Systems Engineering Graduate School of Engineering Nagoya University Fukuoka Japan

Cold energy generation systems must be improved to prevent catastrophic climate change. In this study, we focused on an absorption chiller cycle with HFC-134a and an ionic liquid pair as the refrigerant and absorbent, respectively. It was expected that this absorption chiller cycle could generate cold heat below 0°C. Two liquids were selected and their absorption equilibrium with this pair was evaluated for the absorption chiller cycle. We measured the adsorbed amount at equilibrium with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM][Tf2N] and N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide [N1113][Tf2N]. The experimental results were reproduced using the non-random two liquid (NRTL) model. This analysis model corresponded well in terms of the amount of adsorption at equilibrium with the experimental results. A Duhring diagram was also generated the NRTL model, and the absorption cycle characteristics as a function of temperature were determined. The absorption chiller cycle obtained cold heat at 10°C with a regeneration temperature of 70°C in addition to generating cold heat below 0°C.

关键词： Absorption Chiller Cycle HFC-134a Ionic Liquid Duhring Diagram

Experimental Evaluation of the Heat Output/Input and Coefficient of Performance Characteristics of a Chemical Heat Pump in the Periodic Operation of CaCl2Hydration

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Journal of Materials Science and Chemical Engineering 2020年第11期8卷 33-42页

作者： Atsuhiro Ichinose Kazuki Kuwata takehiro esaki Takayuki Matsuda Noriyuki Kobayashi Nagoya University Furo-cho Chikusa-ku Nagoya Aichi Japan

We herein evaluate the use of a chemical heat pump (CHP) for upgrading waste heat. CaCl2 was used in the system of CHP. We evaluated the heat storage and heat releasing of CHP, and confirmed the practicality from the experimental results. The reactor module employed was an aluminum plate-tube heat exchanger with corrugated fins, and the CaCl2 powder was in the form of a packed bed. Heat storage operation and heat dissipation operation are performed at the same time and supplied to the heat demand destination. At this time, an environmental heat source can be used during the heat radiation operation, and the heat output can release more heat than the heat input during heat storage. The heat discharging and charging characteristics of the reactor module were evaluated experimentally. The coefficient of performance (COP) was calculated for the heat upgrading cycle, and the heat output in the system was determined. A COP of 1.42 and output of 650 W/L, based on the heat exchanger volume, were obtained using a 600 s change time for the heat pump.

关键词： Chemical Heat Pump CaCl2/H2O Hydration Reaction Heat Pump Cycle Coefficient of Performance

Chemical Heat Storage Using an SiC Honeycomb Packed with CaCl2Powder

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Journal of Materials Science and Chemical Engineering 2020年第11期8卷 23-32页

作者： Atsuhiro Ichinose Kazuki Kuwata takehiro esaki Takayuki Matsuda Noriyuki Kobayashi Nagoya University Furo-cho Chikusa-ku Nagoya Aichi Japan

Chemical heat storage is a promising technology for improving thermal energy efficiency. In this study, CaCl2 and H2O were selected as a reaction system for utilization of low-grade exhaust heat that is cooler than 200°C. Heat discharging and charging were conducted through the CaCl2 hydration reaction. A silicon carbide honeycomb was adopted to improve heat transfer in the CaCl2 packed bed. The heat storage, condenser, and evaporator temperature were set at 150°C, 30°C and 90°C respectively. Repeated trials and experiments are time consuming for optimizing design of the equipment. Therefore, in this research, we constructed a simulation that can predict the performance of the device. A numerical simulation model was utilized in preparation for the design of the heat storage module. The consistency of both the simulation and the experimental results was confirmed by comparing them.

关键词： Chemical Heat Storage CaCl2 Heat Discharging Simulation

Evaluation of Performance of Thermal and Electrical Hybrid Adsorption Chiller Cycles with Mechanical Booster Pumps

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Journal of Materials Science and Chemical Engineering 2017年第5期5卷 22-32页

作者： Tao Zeng takehiro esaki Jun Li Noriyuki Kobayashi Hongyu Huang Department of Chemical Engineering Nagoya University Nagoya Japan Integrated Technology Center Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou China

Large amounts of waste heat below 100oC from the industrial sector are re-leased into the atmosphere. It has been suggested that energy system efficiency can be increased with adsorption chillers. However, the cooling power and coefficient of performance (COP) of conventional adsorption chillers significantly decrease with the desorption temperature. In this paper, we proposed a mechanical booster pump (MBP)-assisted adsorption chiller cycle, and evaluated its performances. In the cycle, a MBP was incorporated into a zeolite-water-type adsorption chiller for facilitating water vapor transportation between an adsorber and an evaporator/condenser. We have experimentally studied the effect of the input electrical power of MBP on the performances of adsorption chiller cycle. It has been demonstrated that the heat input achieved by using MBP at the desorption temperature of 50oC was 1.6 times higher than that of without MBP at the desorption temperature of 60oC. And the increase of pump power was found to be effective in increasing the heat input. Therefore, it was confirmed that the operation range of desorption temperature, which can be generated by using the waste heat, was extended and the cooling power was increased directly by using MBP.

关键词： Adsorption Chiller Cycle Zeolite/Water Pair Mechanical Booster Pump

Long-Term Durability and Reactivation of Thermochemical Heat Storage Driven by the CaO/Ca(OH)2Reversible Reaction

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Journal of Materials Science and Chemical Engineering 2017年第11期5卷 23-32页

作者： Kazuki Kuwata takehiro esaki Daichi Iwase Hiroyuki Ito Shijie Li Xixian Yang Hongyu Huang Noriyuki Kobayashi Nagoya University Nagoya Japan Integrated Technology Center Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou China

Thermochemical heat storage is a promising technology for improving thermal energy efficiency. To investigate the durability of the CaO/Ca(OH)2 reaction and develop a reactivation method, repetitive charging/discharging operation of a packed bed reactor with a thick packed bed was conducted, and variations in the discharging behavior, final conversion, and reactant activity were investigated. Owing to the formation of a deactivated sintered reactant block, the discharging time halved and the final conversion ratio decreased by the 53rd discharging operation. To enhance durability, a reactivation method using high-pressure vapor was implemented during the 54th discharging operation. Following reactivation, the final conversion increased 15%, and the discharging time tripled when compared with the discharging operation before reactivation, confirming the success of this simple reactivation method.

关键词： Thermochemical Heat Storage Durability Repetitive Reaction Reactivation CaO/Ca(OH)2 Reaction