(45a) Overview on Mercury Control Options for Coal-Burning Power Plants

With the USEPA expected to issue a national regulation in November 2011 requiring 90% removal of mercury, and many states promulgating their own regulations, the need exists for low-cost mercury removal techniques that can be applied to coal-burning power plants.   The injection of powdered activated carbon into the ductwork upstream of the particulate control device is the most developed technology for mercury capture.  Alternative techniques for mercury capture will also play a role in the near future because of the numerous configurations of air pollution control devices present within the power plants, as well as the many different coals being burned.  These methods employ sorbents, catalysts, scrubber liquors, flue gas or coal additives, combustion modification, flue gas cooling, barrier discharges, and ultraviolet radiation for the removal of mercury from flue gas streams.  The DOE Mercury Program has been a huge success, spurring development, demonstration, and commercialization of many technologies for the capture of mercury. 

An overview of current and alternative technologies for mercury capture from coal-derived flue gas will be provided.  In addition, six patent/patent pending methods for mercury as well as carbon dioxide control within coal-derived flue gas have been recently developed at NETL, and will be discussed.  The future research needs for mercury control include improved sorbent-flue gas contact, development of poison-resistant sorbents and catalysts, new scrubber additives for retention of mercury within wet FGD systems, concrete-friendly activated carbons, new continuous measurement methods, byproducts research, and development of an ASTM standard lab test for sorbent activity for mercury capture.