Entrained-Flow Adsorption of Mercury Using Activated Carbon

• Published in: Journal of the Air & Waste Management Association (1995) 2001-05, Vol.51 (5), p.733-741
• Main Authors: Serre, Shannon D., Gullett, Brian K., Ghorishi, S. Behrooz
• Format: Article
• Language: English
• Subjects: Adsorption; Air Pollution - prevention & control; Air pollution caused by fuel industries; Applied sciences; Atmospheric pollution; Charcoal; Coal; Combustion and energy production; Energy; Energy. Thermal use of fuels; Equipment Design; Exact sciences and technology; Incineration; Mercury - chemistry; Particle Size; Pollution; Pollution reduction; Prevention and purification methods; Stack gas and industrial effluent processing; Static Electricity; Temperature
• ISSN: 1096-2247; 2162-2906
• DOI: 10.1080/10473289.2001.10464302

Bench-scale experiments were conducted in a flow reactor to simulate entrained-flow capture of elemental mercury (Hg 0 ) by activated carbon. Adsorption of Hg 0 by several commercial activated carbons was examined at different C:Hg ratios (by weight) (350:1-29,000:1), particle sizes (4-44 um), Hg 0 concentrations (44, 86, and 124 ppb), and temperatures (23-250 °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 um and a residence time of 6.5 sec. Mercury capture increased with a decrease in particle size. At 100 °C and an Hg 0 concentration of 86 ppb, a 20% Hg 0 reduction was obtained with 4- to 8-um particles, compared with only a 7% reduction for 24- to 44-um particles. Mercury uptake decreased with an increase in temperature over a range of 21-150 °C. Only a small amount of the Hg 0 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 Hg 0 removal for a bituminous-based carbon.