Development of a membrane reactor with a closed-end silica membrane for nuclear-heated hydrogen production

• Published in: Progress in nuclear energy (New series) 2021-07, Vol.137, p.103772, Article 103772
• Main Authors: Myagmarjav, Odtsetseg, Tanaka, Nobuyuki, Nomura, Mikihiro, Noguchi, Hiroki, Imai, Yoshiyuki, Kamiji, Yu, Kubo, Shinji, Takegami, Hiroaki
• Format: Article
• Language: English
• Subjects: Batteries; Chemical reactions; Chemical vapor deposition; Clean energy; Conversion; Counterdiffusion; Decomposition; Decomposition reactions; Hydrogen; Hydrogen production; Hydrogen-based energy; Iodine compounds; Membrane reactor; Membranes; Nuclear energy; Nuclear engineering; Nuclear reactors; Silica membrane; Silicon dioxide; Studies; Sulfur; Sulfuric acid; Thermal expansion; Thermochemical cycle; Water splitting
• ISSN: 0149-1970; 1878-4224
• DOI: 10.1016/j.pnucene.2021.103772

Hydrogen production from nuclear energy has attracted considerable interest as a clean energy solution to address the challenges of climate change and environmental sustainability. With respect to the large-scale and economical production of hydrogen using nuclear energy, the thermochemical water-splitting iodine-sulfur (IS) process is a promising method. The IS process uses sulfur and iodine compounds to decompose water into its elemental constituents, hydrogen and oxygen, by using three coupled chemical reactions: the Bunsen reaction; sulfuric acid decomposition; and hydrogen iodide (HI) decomposition. The decomposition of HI is the efficiency-determining step of the process. In this work, a membrane reactor with a silica membrane closed on one end was designed, and its potential for hydrogen production from HI decomposition was explored. In the reactor-module design, only one end of the membrane tube was fixed, while the closed-end of the tube was freely suspended to avoid thermal expansion effects. The closed-end silica membranes were prepared for the first time by a counter-diffusion chemical vapor deposition of hexyltrimethoxysilane. In application, HI conversion of greater than 0.60 was achieved at a decomposition temperature of 400 °C, which is three times greater than the equilibrium conversion (0.20). Thus, the membrane reactor with closed-end silica membrane was shown to produce a successful equilibrium shift in the production of hydrogen via HI decomposition in the thermochemical IS process. [Display omitted] •A membrane reactor equipped with a silica membrane closed on one end was designed.•Its potential for hydrogen production from HI decomposition was explored.•A closed-end silica membrane was prepared by counter-diffusion CVD method.•In application, HI conversion of greater than 0.60 was achieved at 400 °C.•Developed membrane reactor is applicable for hydrogen production via HI decomposition.