Mercury Measurement and Control Part 3 was Hot Topic Hour Yesterday, April 18^th 

There are lots of technological changes in mercury capture. Four speakers provided insights on the latest developments.

Joe Stuart, TDC, LLC a Division of Genesis Energy Limited, said the industry has missed the opportunity to maximize co-absorption of mercury in wet FGDs.  Applying basic engineering concepts to the mercury issue, an operating condition can be found which reliably avoids stripping of elemental mercury (previously known as “re-emission”), maximizes the ability to absorb elemental mercury up to the mass-transfer limit of the system, and avoids the costs and side-effects of excess oxidation of mercury in the inlet gas. Results from commercial scale trials show that once the scrubbing liquor is returned to a sub-saturated condition, mercury capture is very high. Some of the reports of poor performance are due to a solution already saturated with mercury. After chemical treatment for a few hours, the solution returns to a sub-saturated state.

Mark R. Sankey, Senior Specialist for AQCS at Bechtel Power Corporation, reviewed the effectiveness of existing control equipment and the capabilities of new equipment and technologies as they relate to control of mercury emissions. The concepts of multi-pollutant control, co-benefits, and the interrelationships of various technologies and pollutants were addressed. Some undesirable effects occur due to interactions between various pollutants and technologies.

Neil C. Widmer, Sr. Manager/ Product Line at GE Power and Water, explained that combustion optimization can substantially reduce mercury at the same time it is reducing NO_x and improving combustion.

Robert (Rob) Nebergall, Global Business Manager for Emissions Control at Norit Activated Carbon, discussed recent developments in the technology of activated carbon. New carbons cut the volume of sorbent by 50 percent for the same efficiency. Cabot has acquired Norit and is putting much more funding into R &D. A market for coal-fired activated carbon consumption is anticipated at 400 million to 600 million lbs/yr in the U.S. by 2017. 

Paul Barilla, Applications Engineer, and John Darrow, Associate, at W. L. Gore & Associates, Inc., described  a unique approach to mercury control based on a sorbent polymer composite (SPC) material contained within a fixed-structure located in the gas stream. SPC has a high affinity for absorption and retention of mercury in both elemental and oxidized states and requires no sorbent or chemical addition, thus avoiding potential adverse effects on flyash salability and balance-of-plant equipment. The Gore Mercury Control System (GMCS) is ideally located in a wet FGD absorber vessel downstream of the mist eliminators, where it also serves as a barrier to scrubber re-emissions. Removal of SO₂ is a co-benefit of the GMCS. Pilot scale installations have proved to be low maintenance. Efficiencies as high as 90 percent can be achieved with multiple modules. This means that a system following a 90 percent efficient wet scrubber would obtain another nine percent removal, resulting in an overall efficiency of 99 percent.

Bios, Abstracts and Photos can be seen at: BIOS, ABSTRACTS, PHOTOS - 4-18-13.htm

The individual presentations are as follows:

• Mercury Measurement and Control - Part 3 Webinar - Hot Topic Hour April 18, 2013

• Mercury Removal in a Wet FGD by Joe Stuart, TDC - Hot Topic Hour April 18, 2013
• Application of Combustion Optimization to Reduce Activated Carbon Requirements for MATS Compliance by Neil Widmer, GE - Hot Topic Hour April 18, 2013
• Mercury Control - Activated Carbon Update by Rob Nebergall, Cabot - Hot Topic Hour April 18, 2013
• Mercury Control for Coal-fired Power Plants - Interaction of Other Technologies by Mark Sankey, Bechtel - Hot Topic Hour April 18, 2013
• A Fixed-Structure Approach to Mercury Control for Coal-fired Power Plants by John Darrow and Paul Barilla, W. L. Gore - Hot Topic Hour April 18, 2013