A Hybrid Gas Cleaning Process for Production of Ultraclean Syngas

The overall objective of this project is to develop technologies for cleaning/conditioning IGCC generated syngas to meet contaminant tolerance limits for fuel cell and chemical production applications. The specific goals are to develop processes for (1) removal of reduced sulfur species to sub-ppm levels using a hybrid process consisting of a polymer membrane and a regenerable ZnO-coated monolith or a mixed metal oxide sorbent; (2) removal of hydrogen chloride vapors to sub-ppm levels using an inexpensive, high-surface-area material; and (3) removal of NH3 with acidic adsorbents followed by conversion of this NH3 into nitrogen and water. Existing gasification technologies can effectively and efficiently convert a wide variety of carbonaceous feedstocks (coal, petcoke, resids, biomass, etc.) into syngas, which predominantly contains carbon monoxide and hydrogen. Unfortunately, the impurities present in these carbonaceous feedstocks are converted to gaseous contaminants such as H2S, COS, HCl, NH3, alkali macromolecules and heavy metal compounds (such as Hg) during the gasification process. Removal of these contaminants using conventional processes is thermally inefficient and capital intensive. This research and development effort is focused on investigation of modular processes for removal of sulfur, chlorine, nitrogen and mercury compounds from syngas at elevated temperature and pressures at significantly lower costs than conventional technologies