Mercury Compliance While Avoiding Halogen-Driven Corrosion

EPA’s Mercury and Air Toxic Standards (MATS) requiring stringent emission controls for coal-fired electric generating unit (EGU) power plants will be enforced beginning April 2015. Powdered activated carbons (PACs) have been demonstrated as the leading technology for achieving compliance with the stringent mercury control levels required by MATS. The PACs are sourced as halogenated or non-halogenated materials. In some cases halogens are added to the coal or flue gas stream separately from the PAC. As more of these systems are coming online and accumulating operating hours, issues of plant equipment corrosion are becoming known and work is being done to understand the nature and extent of the problems.  Solutions can include operational changes and/or changes to the materials injected.  We will discuss the design and application of advanced PACs to minimize or avoid corrosion issues and retain effective mercury capture and co-benefit integration with the EGU’s air quality control system (AQCS).