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

The objective of this work is to develop a novel system for regenerable SO{sub 2} and NO{sub x} scrubbing of flue gas that focuses on (a) a novel method for regeneration of spent SO{sub 2} scrubbing liquor and (b) novel chemistry for reversible absorption of NO{sub x}. In addition, high efficiency hollow fiber contactors (BFC) are proposed as the devices for scrubbing the SO{sub 2} and NO{sub x} from the flue gas. The system will be designed to remove more than 95% of the SO{sub x} and more than 75% of the NO{sub x} 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 SO{sub x} and selective catalytic reduction of NO{sub x}. In addition, the process will make 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 SO{sub 2} and NO{sub x}. We will also introduce new process chemistry to minimize traditionally well-known problems with SO{sub 2} and NO{sub x} absorption and desorption. For example, we will extract the SO{sub 2} 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 NO{sub x} will consist of water soluble plithalocyanine compounds invented by SRI and also of polymeric forms of Fe{sup ++} complexes similar to traditional NO{sub x} scrubbing media described in the open literature. Our past work with the phthalocyanine compounds, used as sensors for NO and NO{sub 2} in flue gases, shows that these compounds bind NO and NO{sub 2} reversibly and with no interference from O{sub 2}, CO{sub 2}, SO{sub 2}, or other components of flue gas