Entrained-flow adsorption of mercury using activated carbon.
Bench-scale experiments were conducted in a flow reactor to simulate entrained-flow capture of elemental mercury (Hg0) by activated carbon. Adsorption of Hg0 by several commercial activated carbons was examined at different C:Hg ratios (by weight) (350:1-29,000:1), particle sizes (4-44 microns), Hg0 concentrations (44, 86, and 124 ppb), and temperatures (23-250 degrees C). Increasing the C:Hg ratio from 2100:1 to 11,000:1 resulted in an increase in removal from 11 to 30% for particle sizes of 4-8 microns and a residence time of 6.5 sec. Mercury capture increased with a decrease in particle size. At 100 degrees C and an Hg0 concentration of 86 ppb, a 20% Hg0 reduction was obtained with 4- to 8-micron particles, compared with only a 7% reduction for 24- to 44-micron particles. Mercury uptake decreased with an increase in temperature over a range of 21-150 degrees C. Only a small amount of the Hg0 uptake capacity is being utilized (less than 1%) at such short residence times. Increasing the residence time over a range of 3.8-13 sec did not increase adsorption for a lignite-based carbon; however, increasing the time from 3.6 to 12 sec resulted in higher Hg0 removal for a bituminous-based carbon.
Serre
S D
SD
U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Research Triangle Park, North Carolina, USA. serre.shannon@epa.gov
Gullett
B K
BK
Ghorishi
S B
SB
D000327:Adsorption; D000397:Air Pollution / Q000517:prevention & control*; D002606:Charcoal; D003031:Coal; D004867:Equipment Design; D017745:Incineration; D008628:Mercury / Q000737:chemistry*; D010316:Particle Size; D055672:Static Electricity; D013696:Temperature
D003031:Coal; D002606:Charcoal; D008628:Mercury