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Journal Articles

Introduction of loop operating system to improve the stability of continuous hydrogen production for the thermochemical water-splitting iodine-sulfur process

Tanaka, Nobuyuki; Takegami, Hiroaki; Noguchi, Hiroki; Kamiji, Yu; Myagmarjav, O.; Kubo, Shinji

International Journal of Hydrogen Energy, 46(55), p.27891 - 27904, 2021/08

 Times Cited Count:2 Percentile:17.53(Chemistry, Physical)

The thermochemical water-splitting iodine-sulfur (IS) process enables producing hydrogen. In a previous operation procedure, after the components of the unit operations were individually started, they were connected at the same time. However, it was challenging to stably interconnect the components. This study introduces a new loop operation, subdividing the process configuration into four sections before transferring the continuous operation. The proposed loop operation was validated analyzing the material and heat balances of each section. The calculated results showed that the material balances of respective loop sections were closed. The loop operation mode would transfer to the continuous operation by connect all sections. Regarding the switching of operation modes, the material and heat balance showed no or little difference, indicating that two operation modes could only be changed by switching the pipelines. Consequently, the loop sections could be individually operated to stabilize the IS process system, and the loop operation could be smoothly transferred to the continuous operation.

Journal Articles

Fabrication, permeation, and corrosion stability measurements of silica membranes for HI decomposition in the thermochemical iodine-sulfur process

Myagmarjav, O.; Shibata, Ai*; Tanaka, Nobuyuki; Noguchi, Hiroki; Kubo, Shinji; Nomura, Mikihiro*; Takegami, Hiroaki

International Journal of Hydrogen Energy, 46(56), p.28435 - 28449, 2021/08

 Times Cited Count:2 Percentile:17.53(Chemistry, Physical)

Journal Articles

Hydrogen production using thermochemical water-splitting iodine-sulfur process test facility made of industrial structural materials; Engineering solutions to prevent iodine precipitation

Noguchi, Hiroki; Kamiji, Yu; Tanaka, Nobuyuki; Takegami, Hiroaki; Iwatsuki, Jin; Kasahara, Seiji; Myagmarjav, O.; Imai, Yoshiyuki; Kubo, Shinji

International Journal of Hydrogen Energy, 46(43), p.22328 - 22343, 2021/06

 Times Cited Count:7 Percentile:50.73(Chemistry, Physical)

An iodine-sulfur process offers the potential for mass producing hydrogen with high-efficiency, and it uses high-temperature heat sources, including HTGR, solar heat, and waste heat of industries. R&D tasks are essential to confirm the integrity of the components that are made of industrial materials and the stability of hydrogen production in harsh working conditions. A test facility for producing hydrogen was constructed from corrosion-resistant components made of industrial materials. For stable hydrogen production, technical issues for instrumental improvements (i.e., stable pumping of the HIx solution, improving the quality control of glass-lined steel, prevention of I$$_{2}$$ precipitation using a water removal technique in a Bunsen reactor) were solved. The entire process was successfully operated for 150 h at the rate of 30 L/h. The integrity of components and the operational stability of the hydrogen production facility in harsh working conditions were demonstrated.

Journal Articles

Performance tests of catalysts for the safe conversion of hydrogen inside the nuclear waste containers in Fukushima Daiichi

Reinecke, E.-A.*; Takenaka, Keisuke*; Ono, Hitomi*; Kita, Tomoaki*; Taniguchi, Masashi*; Nishihata, Yasuo; Hino, Ryutaro; Tanaka, Hirohisa*

International Journal of Hydrogen Energy, 46(23), p.12511 - 12521, 2021/03

 Times Cited Count:3 Percentile:27.4(Chemistry, Physical)

The safe decommissioning as well as decontamination of the radioactive waste resulting from the nuclear accident in Fukushima Daiichi represents a huge task for the next decade. At present, research and development on long-term safe storage containers has become an urgent task with international cooperation in Japan. One challenge is the generation of hydrogen and oxygen in significant amounts by means of radiolysis inside the containers, as the nuclear waste contains a large portion of sea water. The generation of radiolysis gases may lead to a significant pressure build-up inside the containers and to the formation of flammable gases with the risk of ignition and the loss of integrity. In the framework of the project "R&D on technology for reducing concentration of flammable gases generated in long-term waste storage containers" funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the potential application of catalytic recombiner devices inside the storage containers is investigated. In this context, a suitable catalyst based on the so-called intelligent automotive catalyst for use in a recombiner is under consideration. The catalyst is originally developed and mass-produced for automotive exhaust gas purification, and is characterized by having a self-healing function of precious metals (Pd, Pt and Rh) dissolved as a solid solution in the perovskite type oxides. The basic features of this catalyst have been tested in an experimental program. The test series in the REKO-4 facility has revealed the basic characteristics of the catalyst required for designing the recombiner system.

Journal Articles

Hydriodic iodide and iodine permeation characteristics of fluoropolymers as a lining material

Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Takegami, Hiroaki; Kubo, Shinji

International Journal of Hydrogen Energy, 45(35), p.17557 - 17561, 2020/07

 Times Cited Count:1 Percentile:4.53(Chemistry, Physical)

The thermochemical water-splitting iodine-sulfur (IS) process requires corrosion-resistant materials owing to usage of a mixture of HI-I$$_{2}$$-H$$_{2}$$O. Fluoropolymers, such as PTFE and PFA, are adaptable as lining materials for protecting plant components. However, there has been a concern: PTFE and PFA have the ability to permeate various permeants. From the viewpoint of corrosion, the permeation of HI and I$$_{2}$$ should be evaluated to improve the integrity of the IS process. In this study, permeation tests on PTFE and PFA membranes were performed to measure the permeated fluxes of HI and I$$_{2}$$, and the effects of the operating conditions on them were investigated. The introduction of a permeability parameter could be successful for normalizing the permeated fluxes for a specific membrane thickness and a vapor pressure. Then, the empirical formula of the permeability was given as an Arrhenius-type equation to use as a plant design.

Journal Articles

Overvoltage reduction in membrane Bunsen reaction for hydrogen production by using a radiation-grafted cation exchange membrane and porous Au anode

Sawada, Shinichi*; Kimura, Takehiro*; Nishijima, Haruyuki*; Kodaira, Takahide*; Tanaka, Nobuyuki; Kubo, Shinji; Imabayashi, Shinichiro*; Nomura, Mikihiro*; Yamaki, Tetsuya*

International Journal of Hydrogen Energy, 45(27), p.13814 - 13820, 2020/05

 Times Cited Count:2 Percentile:9.4(Chemistry, Physical)

An electrochemical membrane Bunsen reaction using a cation exchange membrane (CEM) is a key to achieving an iodine-sulfur (IS) thermochemical water splitting process for mass-production of hydrogen. In this study, we prepared both the radiation-grafted CEM with a high ion exchange capacity (IEC) and the highly-porous Au-electroplated anode, and then used them for the membrane Bunsen reaction to reduce the cell overvoltage. The high-IEC grafted CEM exhibited low resistivity for proton transport, while the porous Au anode had a large effective surface area for anodic SO$$_{2}$$ oxidation reaction. As a result, the cell overvoltage for the membrane Bunsen reaction was significantly reduced to 0.21 V at 200 mA/cm$$^{2}$$, which was only one-third of that of the previous test using the commercial CEM and non-porous anode. From the analysis of the current-voltage characteristics, employment of the grafted CEM was found to be more effective for the overvoltage reduction compared to the porous Au anode.

Journal Articles

H$$_{2}$$ production from methane decomposition by fullerene at low temperature

Tokunaga, Tomoharu*; Kuno, Kohei*; Kawakami, Takumi*; Yamamoto, Takahisa*; Yoshigoe, Akitaka

International Journal of Hydrogen Energy, 45(28), p.14347 - 14353, 2020/05

 Times Cited Count:1 Percentile:4.53(Chemistry, Physical)

To understand the catalytic behavior of graphite and carbon black with mainly 6-membered rings with sp$$^{2}$$ bonds for H$$_{2}$$ production by CH$$_{4}$$ decomposition, fullerenes with 6-membered rings and also those comprising 5- and 7-membered rings with sp$$^{2}$$ bonds was investigated using gas chromatography, XPS and TEM analysis. From these analysis, it is anticipated that the ring structures without 6-membered rings in carbon materials with sp$$^{2}$$ bonding contribute to the catalytic behavior for CH$$_{4}$$ decomposition at a low temperature of 400$$^{circ}$$C.

Journal Articles

Comparison of experimental and simulation results on catalytic HI decomposition in a silica-based ceramic membrane reactor

Myagmarjav, O.; Tanaka, Nobuyuki; Nomura, Mikihiro*; Kubo, Shinji

International Journal of Hydrogen Energy, 44(59), p.30832 - 30839, 2019/11

 Times Cited Count:10 Percentile:39.33(Chemistry, Physical)

Journal Articles

Research and development on membrane IS process for hydrogen production using solar heat

Myagmarjav, O.; Iwatsuki, Jin; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Ioka, Ikuo; Kubo, Shinji; Nomura, Mikihiro*; Yamaki, Tetsuya*; Sawada, Shinichi*; et al.

International Journal of Hydrogen Energy, 44(35), p.19141 - 19152, 2019/07

 Times Cited Count:16 Percentile:56.51(Chemistry, Physical)

Journal Articles

R&D status of hydrogen production test using IS process test facility made of industrial structural material in JAEA

Noguchi, Hiroki; Takegami, Hiroaki; Kamiji, Yu; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Kubo, Shinji

International Journal of Hydrogen Energy, 44(25), p.12583 - 12592, 2019/05

 Times Cited Count:14 Percentile:48.89(Chemistry, Physical)

JAEA has been conducting R&D on thermochemical water-splitting hydrogen production IS process to develop one of heat applications of high-temperature gas-cooled reactor. A test facility was constructed using corrosion-resistant industrial materials to verify integrity of the IS process components and to demonstrate continuous and stable hydrogen production. The performance of components installed in each section was confirmed. Subsequently, a trial operation of integration of the processing sections was successfully carried out for 8 hours with hydrogen production rate of approximately 10 NL/h. After that, hydrogen production operation was extended to 31 hours (approximately hydrogen production rate of 20 NL/h) by introducing a corrosion-resistance pump system with a developed shaft seal technology.

Journal Articles

Module design of silica membrane reactor for hydrogen production via thermochemical IS process

Myagmarjav, O.; Tanaka, Nobuyuki; Nomura, Mikihiro*; Kubo, Shinji

International Journal of Hydrogen Energy, 44(21), p.10207 - 10217, 2019/04

 Times Cited Count:14 Percentile:51.64(Chemistry, Physical)

Journal Articles

Hydrogen production tests by hydrogen iodide decomposition membrane reactor equipped with silica-based ceramics membrane

Myagmarjav, O.; Tanaka, Nobuyuki; Nomura, Mikihiro*; Kubo, Shinji

International Journal of Hydrogen Energy, 42(49), p.29091 - 29100, 2017/12

 Times Cited Count:19 Percentile:53.37(Chemistry, Physical)

The catalytic decomposition of hydrogen iodide in a membrane reactor using silica membranes derived from hexyltrimethoxysilane (HTMOS) was investigated for the production of hydrogen in the thermochemical water splitting iodine-sulfur process. The silica membranes were prepared by counter-diffusion chemical vapor deposition using porous alumina support tubes in both the absence and presence of a $$gamma$$-alumina layer. The silica membranes formed on $$gamma$$-alumina-coated $$alpha$$-alumina tubes displayed a higher H$$_{2}$$ permeance than that formed directly on an $$alpha$$-alumina tube. A silica membrane based on a 1.5 $$mu$$m-thick $$gamma$$-alumina layer fabricated under deposition conditions of 450$$^{circ}$$C, 1200 s, and a N$$_{2}$$ carrier gas velocity of 0.044 m s$$^{-1}$$ exhibited a high H$$_{2}$$ permeance of 9.4 $$times$$ 10$$^{-7}$$ mol Pa$$^{-1}$$ m$$^{-2}$$ s$$^{-1}$$ while maintaining an H$$_{2}$$/N$$_{2}$$ selectivity of over 80.0. The performance of a membrane reactor based on an HTMOS-derived silica membrane was evaluated at 400$$^{circ}$$C by measuring the HI conversion and H$$_{2}$$ flow rates. The conversion was approximately 0.48 when the HI flow rate was 9.7 mL min$$^{-1}$$.

Journal Articles

Current R&D status of thermochemical water splitting iodine-sulfur process in Japan Atomic Energy Agency

Kasahara, Seiji; Iwatsuki, Jin; Takegami, Hiroaki; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Onuki, Kaoru; Kubo, Shinji

International Journal of Hydrogen Energy, 42(19), p.13477 - 13485, 2017/05

 Times Cited Count:47 Percentile:82.83(Chemistry, Physical)

Current R&D on the thermochemical water splitting iodine-sulfur (IS) process in Japan Atomic Energy Agency is summarized. Reactors were fabricated with industrial materials and verified by test operations: a Bunsen reactor, a H$$_{2}$$SO$$_{2}$$ decomposer, and a HI decomposer. Reactors of industrial materials showed corrosion stability. Demonstration of the test facility verified integrity of process components and stability of hydrogen production. An 8 hours continuous operation of the total IS process was performed in February 2016 with H$$_{2}$$ production rate of 10 L/h.

Journal Articles

${{it In situ}}$ X-ray absorption spectroscopy study on water formation reaction of palladium metal nanoparticle catalysts

Matsumura, Daiju; Taniguchi, Masashi*; Tanaka, Hirohisa*; Nishihata, Yasuo

International Journal of Hydrogen Energy, 42(11), p.7749 - 7754, 2017/03

 Times Cited Count:5 Percentile:15.47(Chemistry, Physical)

Journal Articles

Preparation of an H$$_{2}$$-permselective silica membrane for the separation of H$$_{2}$$ from the hydrogen iodide decomposition reaction in the iodine-sulfur process

Myagmarjav, O.; Ikeda, Ayumi*; Tanaka, Nobuyuki; Kubo, Shinji; Nomura, Mikihiro*

International Journal of Hydrogen Energy, 42(9), p.6012 - 6023, 2017/03

 Times Cited Count:19 Percentile:53.37(Chemistry, Physical)

Journal Articles

Characteristics of flow field and pressure fluctuation in complex turbulent flow in the third elbow of a triple elbow piping with small curvature radius in three-dimensional layout

Ebara, Shinji*; Takamura, Hiroyuki*; Hashizume, Hidetoshi*; Yamano, Hidemasa

International Journal of Hydrogen Energy, 41(17), p.7139 - 7145, 2016/05

 Times Cited Count:6 Percentile:17.18(Chemistry, Physical)

In this study, a flow visualization and pressure measurement were conducted by using an experimental setup including test sections of 1/7-scale models of the cold-leg piping of Japan sodium-cooled reactor with high Reynolds number region up to about one million. Regarding the flow field, flow separation appeared in the intrados of the third elbow. However, the separation region was smaller than that observed in the first elbow in the direction normal to the mean flow and was larger in the streamwise direction. This can be considered because of the swirling flow generated downstream of the second elbow which flowed into the third elbow with a little reduction. From the pressure fluctuation test, it was found that prominent frequencies of the pressure fluctuation appeared at about 0.4 in Strouhal number, which corresponds to a nondimensional frequency, in the region from 0 D to 0.4 D downstream of the elbow outlet, where D is the diameter of the piping. And weak peaks of about 0.7 in Strouhal number were observed in the region far 0.75 D downstream of the outlet.

Journal Articles

Spontaneous activation behavior of Ni$$_{3}$$Sn, an intermetallic catalyst, for hydrogen production via methanol decomposition

Fan, M.*; Xu, Y.*; Sakurai, Junya*; Demura, Masahiko*; Hirano, Toshiyuki*; Teraoka, Yuden; Yoshigoe, Akitaka

International Journal of Hydrogen Energy, 40(37), p.12663 - 12673, 2015/10

 Times Cited Count:13 Percentile:29.88(Chemistry, Physical)

The catalytic properties of single-phase Ni$$_{3}$$Sn powder in the production of hydrogen via the decomposition of methanol were investigated in isothermal tests at 713, 793, and 873 K. The catalytic activity of Ni$$_{3}$$Sn significantly increased with time at 793 and 873 K, but not at 713 K, suggesting that Ni$$_{3}$$Sn is spontaneously activated at temperatures above 793 K. At these temperatures, Ni$$_{3}$$Sn showed high selectivity for H$$_{2}$$ and CO production and low selectivity for CH$$_{4}$$, CO$$_{2}$$, and H$$_{2}$$O production, indicating that methanol decomposition was the main reaction, and that side reactions such as methanation and water-gas shift reaction were suppressed. Surface analysis revealed that fine Ni$$_{3}$$Sn particles were formed during the reaction, accompanied by a small amount of deposited carbon. The formation of these particles was suggested to be the cause for the spontaneous activation of Ni$$_{3}$$Sn.

Journal Articles

Hydrogenation of a TiFe-based alloy at high pressures and temperatures

Endo, Naruki*; Saita, Itoko*; Nakamura, Yumiko*; Saito, Hiroyuki; Machida, Akihiko

International Journal of Hydrogen Energy, 40(8), p.3283 - 3287, 2015/03

 Times Cited Count:14 Percentile:37.74(Chemistry, Physical)

Journal Articles

Reduction and unusual recovery in the reversible hydrogen storage capacity of V$$_{1-x}$$Ti$$_x$$ during hydrogen cycling

Kim, H.*; Sakaki, Koji*; Saita, Itoko*; Enoki, Hirotoshi*; Noguchi, Kazuo*; Machida, Akihiko; Watanuki, Tetsu; Nakamura, Yumiko*

International Journal of Hydrogen Energy, 39(20), p.10546 - 10551, 2014/07

 Times Cited Count:11 Percentile:29.33(Chemistry, Physical)

The effect of the vanadium content on the cyclic stability of V-Ti binary alloys was investigated. V$$_{1-x}$$Ti$$_x$$, $$x=$$ 0.2 and 0.5 samples were hydrogenated and dehydrogenated at 410 K and 553 K respectively, for more than 100 times. During hydrogen cycling, reduction in the reversible hydrogen storage capacity was clearly observed from both samples. In addition, the shape of the pressure-composition-isotherm curves was significantly altered over the testing cycle period; the absorption and desorption plateaus got markedly inclined and the hysteresis became evidently smaller. We found that even after the hydrogen storage capacity of V$$_{1-x}$$Ti$$_x$$ was significantly reduced, at low enough temperature V$$_{1-x}$$Ti$$_x$$ was able to absorb hydrogen as much as it did at the first cycle.

Journal Articles

Effect of sulfuric acid on electro-electrodialysis of HIx solution

Tanaka, Nobuyuki; Onuki, Kaoru; Kubo, Shinji

International Journal of Hydrogen Energy, 39(1), p.86 - 89, 2014/01

 Times Cited Count:7 Percentile:18.98(Chemistry, Physical)

The effect of sulfuric acid on the concentration of HIx solution by electro-electrodialysis (EED) was examined for the thermochemical water-splitting iodine-sulfur process. Presence of sulfuric acid in the anolyte HIx solution did not affect the concentration behavior. However, sulfuric acid in the catholyte solution caused side reaction(s) producing whitish precipitates, which indicates that the sulfur compound should be removed prior to the EED operation.

36 (Records 1-20 displayed on this page)