AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Identifying Regimes of Mercury Adsorption Enhancement and Inhibition within Electric Utility ESPs
HEREK CLACK, University of Michigan
Abstract Number: 489 Working Group: Control and Mitigation Technology
Abstract Early mercury emissions control tests operated on the presumption that mercury adsorption within electrostatic precipitators (ESPs) was the result of accumulated fly ash or sorbent deposits on internal ESP collection electrodes. Later developments revealed the role of suspended aerosols, either ash or powdered mercury sorbents. A continuing, implicit assumption has been that the two mechanisms contribute in an additive fashion to overall mercury removal efficiency. The present study computationally models the fluid and electric fields, and the charged aerosol kinematics and mass transfer to demonstrate for the first time that the two mechanisms are coupled. Weakly adsorbing fly ash or sorbent deposits contribute little to overall removal efficiency. However, strongly adsorbing deposits produce mercury-lean regions in which adsorption by suspended particles is diminished. Overall removal efficiency for the two coupled mechanisms is shown to be less than the sum of their individual contributions.