Sulfur-iodine cycle demonstration

The Bench Scale Investigations of the sulfur-iodine cycle include a system which was planned to study the cycle under continuous operation conditions and a smaller unit, the Closed Loop Cycle Demonstrator, aimed at a simple demonstration of the feasibility of the cycle in a closed loop using recycled materials. 

The sulfur-iodine thermo chemical water-splitting cycle continues to represent a promising approach to the production of hydrogen utilizing an entirely thermal energy source. Another significant step toward its viability has been taken by the successful closure of the cycle in this laboratory demonstration. 

Kubo, S. et al., A demonstration study on a closed-cycle hydrogen production by thermochemical water-splitting Iodine-Sulfur process, Nucl. Eng. Des., 233, 347, 2004. 

Kubo, S., et al (2004), A Demonstration Study on a Closed-cycle Hydrogen Production by the Thermochemical Water-splitting Iodine-sulfur Process , Nuclear Engineering and Design, 233, 347-354. 

After completion of the pilot test of Iodine-Sulfur cycle, it is planned to proceed to the demonstration test of nuclear hydrogen production using HTTR. 

A bench-scale test facility for hydrogen production using the thermochemical iodine-sulfur (IS) process has been established at JAERI to verify the hydrogen production, to study the conditions for the reactions, and to gain experience for a large-scale plant [74]. The three reactions (see appendix A.2.3.) are performed in separate sections of the apparatus, the Bunsen reaction and the sulfuric acid decomposition at the same time to avoid SO2 storage (see Fig. 4-8). The process requires temperatures of 800 to 900 °C. Its feasibility was successfully demonstrated in a glass, quartz, and teflon lab-scale apparatus. In the course of six cycles completed, the total amounts of H2 and O2 produced were 16.4 1 and 9.9 1, respectively. The thermal efficiency achieved, however, was much smaller than the theoretical one of 47 - 50 % [44]. In late 1997, the continuous operation of the IS process cycle as a closed loop over 48 h resulted in the production of 44.8 1 of H2 [75]. 

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