Perovskite Adsorbents for Warm-Gas Removal of Sulfur

The DOE is seeking new materials and processes to remove trace quantities of impurities from hydrogen, including sulfur, metals, and other impurities. Currently, oxides based upon zinc are commonly used to remove sulfur from industrial gas streams. However, in the presence of steam, and under warm-gas clean-up conditions (250-450°C), standard industrial adsorbents based upon zinc are not adequate. Sulfur must be reduced to levels in the parts per billion by volume range, in order to prevent poisoning the many types of catalyst used in the production of synthetic fuels. Previous analysis has suggested that a number of elements will form much more stable sulfides relative to those of zinc and, therefore, could be used to form better adsorbents for removal of sulfur in the presence of steam. This project will develop materials with a perovskite crystal structure, which contain elements with high binding energy for sulfur, as improved adsorbents for the warm-gas removal of sulfur. Commercial Applications and other Benefits as described by the awardee: The removal of sulfur from process streams should gain in importance as coal and high-sulfur petroleum feedstocks are increasingly utilized. Warm-gas clean-up would save energy costs relative to processes that require the cooling and re-heating of gas streams, along with the condensation and re-introduction of steam.