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Journal Articles

Components development for sulfuric acid processing in the IS process

Noguchi, Hiroki; Kubo, Shinji; Iwatsuki, Jin; Kasahara, Seiji; Tanaka, Nobuyuki; Imai, Yoshiyuki; Terada, Atsuhiko; Takegami, Hiroaki; Kamiji, Yu; Onuki, Kaoru; et al.

Nuclear Engineering and Design, 271, p.201 - 205, 2014/05

 Times Cited Count:7 Percentile:53.55(Nuclear Science & Technology)

The Japan Atomic Energy Agency has been conducting research and development on a thermochemical iodine-sulfur (IS) process. An examination is planned to verify the integrity of the components in the sulfuric acid decomposition section. A bayonet-type sulfuric acid decomposer made of SiC ceramics, a key component in the section, was test-fabricated. In parallel, a direct-contact heat exchanger (DCHX) is contemplated for use in the sulfuric acid decomposition section to simplify the process. Although the concept is very attractive, little is known about the heat and mass transfer behavior in the DCHX. Therefore, a test apparatus was constructed to measure the gas-phase mass transfer coefficients required for the optimal design of the DCHX. These coefficients of water were acquired and compared with an empirical correlation. The experimental data were in good agreement with those obtained from empirical correlation, and thus, the apparatus was confirmed to be reasonable.

JAEA Reports

Safety measures for integrity test apparatus for IS process (Bunsen section)

Kubo, Shinji; Tanaka, Nobuyuki; Noguchi, Hiroki; Iwatsuki, Jin; Onuki, Kaoru; Inagaki, Yoshiyuki

JAEA-Technology 2012-043, 41 Pages, 2013/02

JAEA-Technology-2012-043.pdf:7.74MB

Providing safety measures for workers and external environments are indispensable in R&D activities of the iodine sulfur water-splitting hydrogen production process, since this process uses toxic chemicals as sulfur dioxide, sulfuric acid, iodine and hydriodic acid. One of the R&D subjects is proof of manufacturability of chemical reactors made of practical structural materials and confirmation of the reactors' sound performance in the harsh process conditions. In order to examine the task, test apparatuses of the process are being constructed; the apparatus for a Bunsen reactor has been built and assembled. Capacities of vessels of the apparatus are about 50-150 liter; normal operating pressure will be 0.5 MPa [abs], and that of temperature will be 90 degrees centigrade. Safety measures for the test apparatus, operations, and in abnormal situations were considered prior to the start of the operation. This report summarizes the results of the considerations.

JAEA Reports

Density of Bunsen reaction solution and viscosity of poly-hydriodic acid

Kubo, Shinji; Yoshino, Koji*; Takemoto, Jumpei*; Kasahara, Seiji; Imai, Yoshiyuki; Onuki, Kaoru

JAEA-Technology 2012-037, 20 Pages, 2013/01

JAEA-Technology-2012-037.pdf:17.29MB

Densities of Bunsen reaction solutions in the iodine-sulfur process were measured with an oscillating U-tube density meter. Two types of the solutions were prepared to simulate sulfuric acid solutions and hydriodic acid solutions of the Bunsen reaction step. The former solution ranged in concentration from 0 to 45 wt% of sulfuric acid containing HI and I$$_{2}$$ of 0-2 mole%; the latter solution contained 0-17 mole% I$$_{2}$$, 1-15 mole% HI and 0-2 mole% H$$_{2}$$SO$$_{4}$$. The temperature of the measured solution were 10-60 $$^{circ}$$C. It was found that, in both solutions, the effect of HI and I$$_{2}$$ concentration on the density could well be represented by using a kind of mole fraction of iodine atom. Based on the finding, a set of correlation equations between the densities and the compositions were derived. Additionally, viscosities of ploy-hydriodic acid were measured using an oscillating viscosity meter in temperature range of 5-40 $$^{circ}$$C, and in the composition range of 0-17 mole% I$$_{2}$$ and 1-15 mole% HI; a empirical equation to calculate viscosity from the composition and the temperature are obtained.

Journal Articles

Components for sulfuric acid processing in the IS process

Noguchi, Hiroki; Kubo, Shinji; Iwatsuki, Jin; Kasahara, Seiji; Tanaka, Nobuyuki; Imai, Yoshiyuki; Terada, Atsuhiko; Takegami, Hiroaki; Kamiji, Yu; Onuki, Kaoru; et al.

Proceedings of 6th International Topical Meeting on High Temperature Reactor Technology (HTR 2012) (USB Flash Drive), 6 Pages, 2012/10

The Japan Atomic Energy Agency (JAEA) has been conducting research and development on a thermochemical iodine-sulfur (IS) process. An examination is planned to verify the integrity of the components in the sulfuric acid decomposition section. A bayonet-type sulfuric acid decomposer made of SiC ceramics, a key component in the section, was test-fabricated. In parallel, a direct-contact heat exchanger (DCHX) is contemplated for use in the sulfuric acid decomposition section to simplify the process. Although the concept is very attractive, little is known about the heat and mass transfer behavior in the DCHX. Therefore, a test apparatus was constructed to measure the gas-phase mass transfer coefficients required for the optimal design of the DCHX. These coefficients of water were acquired and compared with an empirical correlation. The experimental data were in good agreement with those obtained from empirical correlation, and thus, the apparatus was confirmed to be reasonable.

Journal Articles

R&D progress in thermochemical water-splitting iodine-sulfur process at JAEA

Kubo, Shinji; Tanaka, Nobuyuki; Noguchi, Hiroki; Iwatsuki, Jin; Kasahara, Seiji; Imai, Yoshiyuki; Onuki, Kaoru

Proceedings of 6th International Topical Meeting on High Temperature Reactor Technology (HTR 2012) (USB Flash Drive), 6 Pages, 2012/10

Thermochemical iodine-sulfur hydrogen production process is a promising application for the high temperature gas-cooled reactors. To realize this process, one of the key engineering tasks is proof of manufacturability of chemical reactors made of practical structural materials and confirmation of the reactors' sound performance in the harsh working conditions of the process. In order to examine the task, test apparatuses of the process are being constructed by JAEA. The Bunsen section has been built and assembled, the H$$_{2}$$SO$$_{4}$$ decomposer was recently manufactured, and the HI decomposer will be manufactured in FY2012. Throughput of the test apparatus is equivalent of a hydrogen production rate of 150 NL/h, and the design pressure is 0.95 MPa [abs]. The Bunsen reactor was assembled using corrosion resistant materials such as glass- and fluoroplastic-lined steels. The reactor is required to perform multiple functions of mixing the reactants and recycled substances, producing HI and H$$_{2}$$SO$$_{4}$$ by chemical reaction, carrying out heat removal, and separating products and gases. The reactor features an outer-circulating, co-current system to perform the said functions via a relatively simple mechanism. At first, performance of chemical reaction will be tested, followed by long-term service test of the reactors to demonstrate the durability of the construction materials. The results are expected to prove the promising engineering advances toward the practical use of Bunsen reactor that is a core device of this process.

Journal Articles

Simulation study about the effect of pressure on purification of H$$_{2}$$SO$$_{4}$$ and HIx phases in the iodine-sulfur hydrogen production cycle

Wang, L.*; Imai, Yoshiyuki; Tanaka, Nobuyuki; Kasahara, Seiji; Kubo, Shinji; Onuki, Kaoru; Chen, S.*; Zhang, P.*; Xu, J.*

International Journal of Hydrogen Energy, 37(17), p.12967 - 12972, 2012/09

 Times Cited Count:12 Percentile:30.1(Chemistry, Physical)

Optimization of purification operation of the Bunsen reaction products, H$$_{2}$$SO$$_{4}$$ phase and HIx phase, is one of the problems for industrialization of the thermochemical hydrogen production iodine-sulfur process. HI impurity is contained in H$$_{2}$$SO$$_{4}$$ phase, and H$$_{2}$$SO$$_{4}$$ impurity is in HIx phase: these impurities should be removed by purification. Effect of pressure on purification of these phases was simulated as an investigation of the operation by a chemical process simulator ESP with a thermodynamic database based on the Mixed Solvent Electrolyte model. The simulation was of the reaction equilibrium and phase equilibrium. As the result of the simulation in the range of 0.2-6 bar, effective removal of impurities and suppression of undesirable side reactions were suggested in the purification of H$$_{2}$$SO$$_{4}$$ phase at below atmospheric pressure. On the other hand, advantageous pressure in the viewpoint of equilibrium was not found in purification of HIx phase.

Journal Articles

Thermochemical hydrogen production IS process

Iwatsuki, Jin; Kubo, Shinji; Kasahara, Seiji; Tanaka, Nobuyuki; Noguchi, Hiroki; Imai, Yoshiyuki; Onuki, Kaoru

Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 3 Pages, 2012/07

The Japan Atomic Energy Agency (JAEA) is conducting research and development on nuclear hydrogen production using High Temperature Gas-cooled Reactor and thermochemical water-splitting Iodine-Sulfur (IS) process aiming to develop large-scale hydrogen production technology for "hydrogen energy system". In this paper, the present status of R&D on IS process at JAEA is presented which focuses on examining integrity of such components as chemical reactors, separators, etc. Based on previous screening of materials of construction mainly from the viewpoint of corrosion resistance in the harsh process conditions of IS process, it was planned to fabricate the IS components and examine their integrity in the process environments. At present, among the components of IS process plant consisting of three chemical reaction sections, key components in the Bunsen reaction section was fabricated.

Journal Articles

Present status of hydrogen production and the ammonia production by the thermochemical cycle; Introduction of IS cycle and ISN cycle

Kameyama, Hideo*; Sakurai, Makoto*; Masuda, Akiyuki*; Fukui, Tomoaki*; Onuki, Kaoru; Kubo, Shinji; Imai, Yoshiyuki

Suiso Enerugi Shisutemu, 37(1), p.3 - 10, 2012/03

The technical present status of hydrogen production process using IS thermochemical cycle was introduced. This process is experimentally investigated in Japan, U.S.A., Germany, France, Italy, India, China and Korea. Japan Atomic Energy Agency succeeded in consecutive hydrogen production as a proof examination. The trend of the research and development about the reactions, separation technology, device materials and the process equipment were reported. Thermochemical ammonia production cycle was also introduced. This new cycle is named ISN cycle which was modified from IS cycle in order to produce ammonia from water and nitrogen.

Journal Articles

Thermodynamic considerations on the purification of H$$_{2}$$SO$$_{4}$$ and HIx phases in the iodine-sulfur hydrogen production process

Wang, L.*; Imai, Yoshiyuki; Tanaka, Nobuyuki; Kasahara, Seiji; Kubo, Shinji; Onuki, Kaoru

Chemical Engineering Communications, 199(2), p.165 - 177, 2012/02

 Times Cited Count:9 Percentile:32.37(Engineering, Chemical)

Small amount of HI and I$$_{2}$$ are contained in H$$_{2}$$SO$$_{4}$$ phase and a little H$$_{2}$$SO$$_{4}$$ is contained in HIx phase obtained from the Bunsen reaction in the thermochemical water splitting IS process. A thermodynamical investigation of purification to separate and recover these components was made by a chemical process simulator ESP to clarify effects of temperature and stripping gas on reaction and phase equilibrium. The reverse Bunsen reaction, which change HI to I$$_{2}$$, and I$$_{2}$$ vaporization are dominant at higher temperatures than ca. 110$$^{circ}$$C for H$$_{2}$$SO$$_{4}$$ phase. The temperature can be extended to be lower by inert gas stripping. Purification of the solution without loss of H$$_{2}$$SO$$_{4}$$ is expected by oxidation of HI to I$$_{2}$$ by O$$_{2}$$ stripping. Though temperature range where purification by reverse Bunsen reaction is available is limited for HIx phase because of S and H$$_{2}$$S production reactions, the range can be widen by inert gas stripping.

Journal Articles

R&D status on thermochemical IS process for hydrogen production at JAEA

Kubo, Shinji; Tanaka, Nobuyuki; Iwatsuki, Jin; Kasahara, Seiji; Imai, Yoshiyuki; Noguchi, Hiroki; Onuki, Kaoru

Energy Procedia, 29, p.308 - 317, 2012/00

 Times Cited Count:11 Percentile:92.73

Japan Atomic Energy Agency (JAEA) has been conducting R&D of the thermochemical water splitting iodine-sulfur (IS) process since the end of 1980s. This paper presents the recent study on the IS process in JAEA. In 2005-2009, test-fabrication of components, collection of design database, improvement of process components for higher thermal efficiency, and proposition of composition measurement method were carried out. On the basis of them, the integrity test of process components is carried out in 2010-2014 to examine their integrities in severe process environments. At present, a Bunsen reactor, which produces acids, and incidental equipments has been already manufactured using corrosion resistant materials such as glass lining steel and fluoroplastic lining steel. Data acquisition to examine the functionality and integrity of the materials starts in 2012.

Journal Articles

R&D on thermochemical IS process for nuclear hydrogen production at JAEA

Onuki, Kaoru; Kubo, Shinji; Iwatsuki, Jin; Kasahara, Seiji; Tanaka, Nobuyuki; Imai, Yoshiyuki; Noguchi, Hiroki

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 2 Pages, 2011/12

The Japan Atomic Energy Agency (JAEA) has been conducting research and development of thermochemical water-splitting Iodine-Sulfur (IS) process for nuclear hydrogen production using High Temperature Gas-cooled Reactor. Based on the previous studies on the closed-cycle operation techniques and on the process components using materials of construction selected upon the accumulated knowledge on corrosion in the harsh process environments, a new R&D program was started to fabricate the components and examine their integrity in the actual process environments of IS process. So far, key components in the Bunsen reaction section have been test-fabricated.

Journal Articles

Flowsheet study of HI separation process from HI-H$$_{2}$$O-I$$_{2}$$ solution in the thermochemical hydrogen production iodine-sulfur (IS) process

Kasahara, Seiji; Guo, H.*; Tanaka, Nobuyuki; Imai, Yoshiyuki; Iwatsuki, Jin; Kubo, Shinji; Onuki, Kaoru

Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 8 Pages, 2011/10

Flowsheet investigation of the subsection of HI separation from HI-H$$_{2}$$O-I$$_{2}$$ solution in the thermochemical hydrogen production iodine-sulfur (IS) process was performed. Concentration of HI by electro-electrodialysis (EED) and distillation of HI were applied. Experimental data of the EED cell applying Nafion membrane was used to establish heat/mass balance equations for the cell. Heat/mass balance of HI distillation column was calculated using ESP, a process simulation software. HI molality at the cathode outlet of the cell, pressure in the HI distillation column, and flow rate ratio of the feed to the subsection to distillate of the column were focused as variable parameters for minimum heat demand. Parameters of the EED membrane, electric resistance and upper limit of HI molality between outlet streams, had a great effect on the heat demand; improvement of the membrane parameters is important to reduce the heat demand.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:176 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:7 Percentile:49.81(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Evaluation of required activity of SO$$_{3}$$ decomposition catalyst for iodine-sulfur process

Imai, Yoshiyuki; Kubo, Shinji; Goto, Minoru; Shimakawa, Satoshi; Tachibana, Yukio; Onuki, Kaoru

Proceedings of 5th International Topical Meeting on High Temperature Reactor Technology (HTR 2010) (CD-ROM), 4 Pages, 2010/10

Required performance of SO$$_{3}$$ decomposition catalyst for Iodine-Sulfur process was investigated. Heat transfer area needed for shell and tube type SO$$_{3}$$ decomposer exchanging heat from VHTR was calculated by applying Yagi-Kunii and Zukauskas's equation for filled layer-SiC tube and SiC tube-He gas flow heat transfer respectively and the minimum space velocity for catalyst was 1000 h$$^{-1}$$. To transform minimum space velocity to more universal kinetic rate constant, we introduced forward/reverse SO$$_{3}$$ decomposition equation. To achieve equilibrium SO$$_{3}$$ decomposition ratio above 0.5 MPa, rate constant k$$_{1}$$ should be more than 1.5 s$$^{-1}$$ for SO$$_{3}$$ decomposition catalyst.

Journal Articles

Strength assessment of SiC components used in IS process hydrogen production

Takegami, Hiroaki; Terada, Atsuhiko; Onuki, Kaoru; Inagaki, Yoshiyuki

Nihon Kikai Gakkai 2010-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.165 - 166, 2010/09

The Japan Atomic Energy Agency has been conducting R&D on thermochemical water-splitting Iodine-Sulfur (IS) process for hydrogen production to meet massive demand in the future hydrogen economy. A concept of sulfuric acid decomposer was developed featuring a heat exchanger block made of silicon carbide (SiC). Recent activity has focused on the reliability assessment of SiC block. Although knowing the strength of SiC component is important for the reliability assessment, it is difficult to evaluate a large-scale ceramics structure without destructive test. A novel approach for strength estimation of SiC structure has been proposed. In this study, the validity of proposed estimation method was confirmed by comparison with probability of failure, which is conventional method for reliability assessment of ceramic components. The proposal method was effective for strength estimation of a component of large-scale effective volume.

Journal Articles

Research and development on thermochemical process for nuclear production of hydrogen

Onuki, Kaoru; Kubo, Shinji; Iwatsuki, Jin; Kasahara, Seiji; Tanaka, Nobuyuki; Imai, Yoshiyuki

Suiso Enerugi Shisutemu, 35(3), p.53 - 55, 2010/09

Outline of the study on thermochemical IS process for hydrogen production performed by the IS process technology group of JAEA was described in the field of closed-loop continuous hydrogen production, screening of corrosion-resistant materials of construction, development of chemical reactors made of ceramics, and improvement of hydrogen production efficiency.

Journal Articles

Effect of sulfur dioxide partial pressure and reaction temperature on the product composition of the Bunsen reaction

Imai, Yoshiyuki; Nakajima, Hayato; Kubo, Shinji; Onuki, Kaoru

Kagaku Kogaku Rombunshu, 36(1), p.70 - 73, 2010/01

 Times Cited Count:5 Percentile:23.23(Engineering, Chemical)

Effect of sulfur dioxide partial pressure and reaction temperature on the composition of the poly-hydriodic acid solution produced in the Bunsen reaction, which is a unit reaction in the IS process for thermochemical hydrogen production, was studied experimentally under iodine saturation. The ratio of (HI/(HI/H$$_{2}$$O)) of the poly-hydriodic acid solution assuming an ideal desulfurization was increased with sulfur dioxide partial pressure and reaction temperature. The experimental equation on the ratio of (HI/(HI/H$$_{2}$$O)) was obtained as a function of sulfur dioxide partial pressure and reaction temperature.

Journal Articles

A Simulation study for closed cycle and continuous hydrogen production by a thermo-chemical water-splitting IS process

Kubo, Shinji; Kasahara, Seiji; Sato, Hiroyuki; Imai, Yoshiyuki; Iwatsuki, Jin; Tanaka, Nobuyuki; Miyashita, Reiko*; Tago, Yasuhiro*; Onuki, Kaoru

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/12

A stable hydrogen production via the IS process is relatively difficult because of the unique characteristics of the closed-cycle condition involved. This issue is therefore a high targeted priority when industrializing the process as feasible in a chemical plant. In system of IS process coupled with helium gas heat source, a process control method to maintain mass balance of the process was devised. The method is equipped with measurements of Bunsen reaction composition and allocation of heat for the O$$_{2}$$ and H$$_{2}$$ production sections in strict proportion. Via computer simulation for closed-cycle and fully multi-section driven by high-temperature helium gas, the system worked automatically to maintain stoichiometric production ratio in response to shifts of helium gas conditions.

Journal Articles

A Simulation study of catalytic SO$$_{3}$$ decomposition in heat exchanger reactor

Kubo, Shinji; Tanaka, Nobuyuki; Ohashi, Hirofumi; Kanagawa, Akihiro*; Imai, Yoshiyuki; Kasahara, Seiji; Onuki, Kaoru

Proceedings of 2008 AIChE Annual Meeting (CD-ROM), 8 Pages, 2008/11

SO$$_{3}$$ decomposition is common chemical reaction employed by thermochemical water-splitting cycles for hydrogen. This reaction proceeds endothermically in catalytic bed; in heat utilization system of the VHTR, needed heat is provided from high temperature helium gas by heat exchange. To specify sizes and shape of this reactor, the kinetics of SO$$_{3}$$ decomposition reaction was formulated by a Pt catalyst experiments for primary simple and easy in engineering utilization; besides, the ordinary differential equation for catalytic bed, in which the kinetic and heat exchange were considered, were computed. The characteristics length $$z$$ which represented reactor shapes and the required heat transfer area were shown to attain nearly chemical equilibrium.

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