Advanced separation technology for flue gas cleanup: Quarterly technical report No. 16, January 1996--March 1996

摘要

The objective of this work is to develop a novel system for regenerable SO2 and NOx scrubbing of flue gas that focuses on (a) a novel method for regeneration of spent SO2 scrubbing liquor and (b) novel chemistry for reversible absorption of NOx. In addition, high efficiency hollow fiber contactors (BFC) are proposed as the devices for scrubbing the SO2 and NOx from the flue gas. The system is designed to remove more than 95% of the SOx and more than 75% of the NOx from flue gases typical of pulverized coal-fired power plants at a cost that is at least 20% less than combined wet limestone scrubbing of SOx and selective catalytic reduction of NOx. In addition, the process makes only marketable byproducts, if any (no waste streams). The major cost item in existing technology is capital investment. Therefore, our approach is to reduce the capital cost by using high efficiency hollow fiber devices for absorbing and desorbing the SO2 and NOx. We also introduce new process chemistry to minimize traditionally well-known problems with SO2 and NOx absorption and desorption. For example, we extract the SO2 from the aqueous scrubbing liquor into an oligomer of dimethylaniline to avoid the problem of organic liquid losses in the regeneration of the organic liquid. Our novel chemistry for scrubbing NOx consists of water soluble plithalocyanine compounds invented by SRI and also of polymeric forms of Fe(sup ++) complexes similar to traditional NOx scrubbing media described in the open literature.