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ELEMENTAL MERCURY CAPTURE BY ACTIVATED CARBON IN A FLOW REACTOR
Citation:
Serre**, S D., B K. Gullett*, AND S. B. Ghorishi. ELEMENTAL MERCURY CAPTURE BY ACTIVATED CARBON IN A FLOW REACTOR. Presented at AWMA Conference, Salt Lake City, Utah, 6/18-22/2000.
Description:
The paper gives results of bench-scale experiments in a flow reactor to simulate the entrained-flow capture of elemental mercury (Hgo) using solid sorbents. Adsorption of Hgo by a lignite-based activated carbon (Calgon FGD) was examined at different carbon/mercury (C/Hg) ratios (by weight) (2100/1-29000/1), particle sizes (4-44 micrometers), Hgo concentrations (44, 86, and 124 ppb), and temperatures (23-250?C). Increasing the C/Hg ratio from 2100/1 to 11000/1 resulted in an increase in removal from 11 to 30% for particle sizes of 4-8 micrometers and a residence time of 6.5 s. Mercury capture increased with a decrease in particle size. At 100?C and a Hg concentration of 86 ppb, a 20% Hg reduction was obtained with 4-8 micrometer particles, compared to only a 7% reduction for 24-44 micrometer particles. Mercury uptake decreased with an increase in temperature over a range of 21-150?C. Only a small amount of the Hgo uptake capacity is being utilized (< 0.1%)at such residence times, indicating that reactivity or initial rate of uptake is more important than saturation capacity for the short time scale capture of Hgo. Increasing the residence time over a range of 3.8-13 s did not increase adsorption. The rate of uptake appears to be rapid and then decreases with time.