Heavy Metal Contaminant Sequestration in Ash by PAC

摘要

Activated Carbon Injection (AO) in flue gas is a leading technology used by EGUs to comply with the EPA's Mercury and Air Toxics Standard (MATS) rule. Newer regulations regarding solid byproducts under the Coal Combustion Residuals (CCR) rule and potential regulations requiring treatment of scrubber discharge under the Effluent Limitations Guidelines (ELG) rule have shifted environmental compliance priorities from single point emission control to a more holistic understanding of the fate and stability of multiple contaminants. This study investigates the potential co-benefits of ACI on removing contaminants, such as arsenic, selenium, and mercury, from the flue gas and enhancing fly ash retention of the same. Using activated carbon for capture upstream of a wFGD could irreversibly sequester pollutants in a way that does not disrupt process operations. The study demonstrates improvements in retention of multiple heavy metals when activated carbon is used. Potential benefits include reducing the size and cost of backend effluent treatment systems and improving control of the fate of trace contaminants.