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IN-FLIGHT CAPTURE OF ELEMENTAL MERCURY BY A CHLORINE-IMPREGNATED ACTIVATED CARBON
Citation:
Ghorishi, S. B., R. Keeney, W. Jozewicz, S D. Serre**, AND B K. Gullett*. IN-FLIGHT CAPTURE OF ELEMENTAL MERCURY BY A CHLORINE-IMPREGNATED ACTIVATED CARBON. Presented at 94th Annual AWMA Conference, Orlando, Florida, 6/24/-28/01.
Description:
The paper discusses the in-flight capture of elemental mercury (Hgo) by a chlorine (C1)-impregnated activated carbon. Efforts to develop sorbents for the control of Hg emissions have demonstrated that C1-impregnation of virgin activated carbons using dilute solutions of hydrogen chloride (HC1) leads to substantial increases in Hg capture. HC1 treatment at ambient temperature of a commonly used, commercially available activated carbon--DARCO FGD, NORIT Americas, Inc. (FGD)--has previously been shown to result in significant improvement in the fixed=bed captue of Hgo and mercuric chloride (HgC12). In the study presented here, the C1-impregnation process was optimized for Hg capture based on comparative testing in a bench-scale, fixed-bed Hgo adsorption system. The optimzed sorbent was then produced on a larger scale (5 lb per batch) and tested for in-flight, short-time-scale capture of Hgo in a flow reactor. The sorbent wa entrained in Hgo-laden flue gases of varied compositions with gas/solid contact times of about 3 - 4 s. C1-impregnated FGD exhibited significant Hgo removal (80-90%), compared to virgin FGD (10-15%), across the whole range of very low carbon-to-mercury weight ratios (1000-1 to 5000-1). Preliminary cost estimates indicated that approximately 53% reduction of the total annual cost of Hg control could be possible when using C1-impreganted FGD.