Evaluation and Characterization of Membranes for HI/H2O/I2 Water Separation for the S-I Cycle

Technical Report · Thu Sep 01 04:00:00 EDT 2005

DOI:https://doi.org/10.2172/911782· OSTI ID:911782

Stewart, Frederick F

In the Sulfur-Iodine (S-I) thermochemical cycle, iodine is added to the product of the Bunsen reaction to facilitate the separation of sulfuric acid (H2SO4) from hydriodic acid (HI). The amount of iodine can be as high as 83% of the overall mass load of the Bunsen product stream, which potentially introduces a large burden on the cycle’s efficiency. Removal of water from the HI and I2 mixture would substantially reduce the amount of required additional iodine. In this work, Nafion® membranes have been studied for their use as de-watering membranes. Specifically, two thicknesses of Nafion membranes have been found to be effective in this application. The thicker membrane, Nafion-117®, produces moderate fluxes of water with very high separation factors. On the other hand, the thinner membrane, Nafion-112®, yielded very large fluxes of water, however with smaller separation factors. All membranes were found to be durable and did not degrade in contact with the feed stream over periods of time up to three months.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: DOE - NE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 911782
• Report Number(s): INL/EXT-05-00723
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
EFFICIENCY
EVALUATION
HYDRIODIC ACID
IODINE
MEMBRANES
MIXTURES
REMOVAL
SULFURIC ACID
WATER
iodine
separation
sulfur-iodine thermochemical cycle