Abstract—Japan Atomic Energy Agency (JAEA) has been conducting research and development on the iodine-sulfur (IS) thermochemical water-splitting process for hydrogen production as one of the heat applications of High Temperature Gas-Cooled Reactor. The iodine-sulfur (IS) process is one of the most promising thermochemical process because of its potential for large-scale, economical and CO
2 free hydrogen production. The IS process consists three chemical reactions: Bunsen reaction, sulfuric acid (H
2SO
4) decomposition reaction and hydrogen iodide (HI) decomposition reaction. In each reaction, high corrosion resistance is required of the construction materials since highly corrosive chemicals such as HI, iodine and H
2SO
4 are used as working fluids in the various phases over a wide temperature range.
HI may be decomposed in gas phase using solid catalysts at temperatures around 500°C. We fabricated a HI decomposer and examined corrosion of test specimens made of Nickel-based alloy (Hastelloy C-276) set in the actual HI decomposition environment, using pure HI as the feed gas. The experiments were carried out at 500°C and atmospheric pressure for 100h in total. Corrosion rates were evaluated from the weight change of each specimen after exposure. Test specimens set in the catalyst layer suffered relatively severe corrosion (< 0.75 mm/y) in comparison with those set before the catalyst layer (< 0.52 mm/y). It is noted that the observed corrosion rates were larger than those of previous studies performed in the co-existence of steam.
Index Terms—Hydrogen production, thermochemical process, water splitting, iodine-sulfur process, hydrogen iodide, iodine, corrosion, nickel-based alloy.
The authors are with the Japan Atomic Energy Agency/HTGR Hydrogen and Heat Application Research Center, Oarai, Japan (e-mail: kamiji.yu@jaea.go.jp, onukikaoru@jaea.go.jpp, shinjikubo@jaea.gp.jp).
[PDF]
Cite: Yu Kamiji, Kaoru Onuki, and Shinji Kubo, "Corrosion Resistance of Nickel-Based Alloy to Gaseous Hydrogen Iodide Decomposition Environment in Thermochemical Water-Splitting Iodine-Sulfur Process," International Journal of Chemical Engineering and Applications vol. 9, no. 5, pp. 167-170, 2018.
