A demonstration study on a closed-cycle hydrogen production by the thermochemical water-splitting iodine–sulfur process

Kubo, S.; Nakajima, Hayato; Kasahara, Seiji; Higashi, Syunichi; Masaki, Tomoo; Abe, Hiroyoshi; Onuki, Kaoru

doi:10.1016/j.nucengdes.2004.08.025

Cited by 218 publications

(58 citation statements)

References 3 publications

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“…Giaconia et al (2007) had optimized operating range but it appeared closer to lower bound specified by Sakurai et al (2000a). Kubo et al (2004) has good temperature range but prefer more excess water. Lee et al (2008) studied experimental data to present optimal window with lower temperature range specified of 330-350 K. Present study considers recent experimental work including azeotropic range, SO2 absorption, and reverse Bunsen reaction and suggest a precise operating range of 345-360 K for whole SI cycle to be economical.…”

Section: Best Operating Conditions and Comparison With Operating Rangmentioning

confidence: 93%

Effects of Excess Iodine and Water on Bunsen Reaction for Over-Azeotropic Limit

Satpute¹,

Park

Revankar

2015

ACER

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Phase separation is of major importance in a Bunsen reaction in sulfur-iodine thermochemical cycle for hydrogen generation. Extensive experimental data on Bunsen reaction was collected and assembled over range of reaction temperature 293 -393.5 K, excess iodine in the range of 1-16 moles, and excess water in the range of 1-22 moles. The data was systematically analyzed to see key parametric effects on the reaction. The effects of iodine, water and temperature were studied on density ratio, distribution of components in two phases, reverse Bunsen reaction, SO2 dissolution, and azeotrope limits. Best operating conditions were obtained to for which Bunsen reaction would be economical. The analysis indicated that iodine excess of 4 to 6 moles, water excess of 10.5 to 12.5 moles, and temperature range of 345-360 K are the best operating range for the Bunsen reaction. These operating ranges ensure no side reaction, economical operation by avoiding excess iodine, water and complicated options to break or bypass azeotrope. In addition reverse Bunsen and SO2 solubility study are also considered for better understanding of process. Based on this study unique points of operation are recommended.

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Section: Best Operating Conditions and Comparison With Operating Rangmentioning

confidence: 93%

Effects of Excess Iodine and Water on Bunsen Reaction for Over-Azeotropic Limit

Satpute¹,

Park

Revankar

2015

ACER

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“…An alternative way to reduce the temperatures involved includes the utilization of cycles incorporating more than two steps. Examples are the three-step manganese cycle (Sturzenegger and Nüesch, 1999) or the three-step sulfur-iodine cycle (Kubo et al, 2004), requiring temperatures for full reaction conversion in the range of 1600 and 1400 K, respectively. Another way to reduce the reduction temperature is by hybridizing the solar-driven process with a carbon source for carbothermal reduction.…”

Section: Introduction and Historical Backgroundmentioning

confidence: 99%

High-flux optical systems for solar thermochemistry

et al. 2017

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a b s t r a c tHigh-flux optical systems (HFOSs) are optical concentrators used to increase the radiative flux of the natural terrestrial solar irradiation. High radiative flux concentration leads to high energy density in solar receivers which allows to obtain high temperatures. In solar thermochemical applications, the hightemperature heat drives endothermic thermochemical reactions. HFOSs have been deployed for research and development of solar thermochemical devices and systems, from solar reacting media to solar reactors. Here, we review the designs and characteristics of HFOSs as well as challenges and opportunities in the area of high-flux optical systems for solar thermochemical applications.

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“…6,7) JAEA has constructed Japan's first HTGR, the high-temperature engineering test reactor (HTTR), with a thermal output of 30 MW and an outlet coolant temperature of 950 C. 8,9) JAEA also has been developing a thermochemical water-splitting iodine-sulfur (IS) process, which can produce hydrogen from water at a temperature lower than 1000 C. 10,11) Since connecting the IS process to the HTGR can produce a large amount of hydrogen without CO 2 emission, this system is a promising candidate for CO 2 -free energy production. The HTTR-IS system 12) is planned as a coupling of the IS process with the HTTR in order to demonstrate hydrogen production with the HTGR and to obtain technical and capital cost data for such future commercial plants as the GTHTR-300C.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Tritium Behavior by Using Isotope Exchange Reactions in Thermochemical Water-Splitting Iodine–Sulfur Process

Ohashi

Sakaba

Nishihara

et al. 2007

J. Nucl. Sci. Technol.

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One potential problem in the hydrogen production system coupled with the high-temperature gascooled reactor (HTGR) is transmission of tritium from the primary coolant to the product hydrogen by permeation through the heat transfer tubes. Tritium accumulation in the process chemicals in the components of a hydrogen plant, a thermochemical water-splitting iodine-sulfur (IS) process, will also be a critical issue in seeking to license the hydrogen plant as a non-nuclear plant in the future. A numerical analysis model for tritium behavior in the IS process was developed by considering the isotope exchange reactions between tritium and the hydrogen-containing process chemicals, i.e., H 2 O, H 2 SO 4 and HI. The tritium activity concentration in the IS process coupled with the high-temperature engineering test reactor (HTTR), the HTTR-IS system, was preliminarily evaluated in regard to the effects of some indeterminate parameters, i.e., equilibrium constants of the isotope exchange reactions, permeability of tritium through heat transfer tubes, tritium and hydrogen concentrations in the secondary helium coolant, and the leak rate from the secondary coolant loop. The results describing how the tritium activity concentration changes with variations in these parameters and which component has the maximum tritium activity concentration in the IS process are described in this paper.

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A demonstration study on a closed-cycle hydrogen production by the thermochemical water-splitting iodine–sulfur process

Cited by 218 publications

References 3 publications

Effects of Excess Iodine and Water on Bunsen Reaction for Over-Azeotropic Limit

Effects of Excess Iodine and Water on Bunsen Reaction for Over-Azeotropic Limit

High-flux optical systems for solar thermochemistry

Numerical Study on Tritium Behavior by Using Isotope Exchange Reactions in Thermochemical Water-Splitting Iodine–Sulfur Process

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