Assessment and Investigation of Containment Materials for the Sulfur-Iodine Thermochemical Water-Splitting Process for Hydrogen Production

摘要

This report summarizes the materials investigations conducted at General Atomic to support the on-going process development of the sulfur-iodine thermochemical water-splitting process to produce hydrogen. It presents data from compatibility tests in which candidate construction materials were exposed to chemical and temperature environments simulating the principal process fluids of the water-splitting cycle. The environments were (1) mixtures of HI-H2O-I2 and I2 in the range of 295 to 423 K, (2) H2SO4 acid (60 wt%) at 398 K, and (3) H2SO4 vapor decomposition products at 1173 K. The program group identified commercial construction materials for each environment. These materials demonstrated adequate compatibility for use in the conceptual design of a pilot plant and a commercial-size process plant. Mixtures of HI-H2O-I2 were very corrosive to most metals and alloys used in the chemical industry. Increased temperature rapidly accelerated corrosion and increased absorption in fluorocarbon plastics and elastomers. These investigations helped to select candidate materials, including metals, alloys, ceramics, plastics, and elastomers, to handle many of the more aggressive and corrosive fluids anticipated in the chemical process operation.