SBIR-STTR Award

The Phase I objective is to develop a sampling system that differentiates the elemental and oxidized forms of mercury for reliable sample transport to any of several existing real-time analyzers. Mercury emission from combustion sources is recognized as a major concern to the Nation's air quality. However, mercury emissions measurements from coal-fired utility boilers are difficult to make due to low mercury concentrations and interfering gas species. A sample conditioning system that removes interfering species and stabilizes the mercury for measurements would allow real-time, continuous measurements. Control of mercury emissions from coal-fired utility boilers currently is being considered, and if implemented, will likely cost billions of dollars each year. Apogee Scientific, Inc.'s proposed sampling system could assure compliance with regulations and lower costs through more appropriate technology implementation and advanced process control. Furthermore, the health effects of mercury emissions from coal-fired combustion sources cannot be fully evaluated nor can controls be cost-effectively implemented unless the emissions can be accurately measured. The proposed system will enable accurate mercury measurements.

Mercury from combustion sources is a major concern to the nation's air quality. In December 2000, EPA announced that it would regulate mercury emissions from coal-fired boilers under Title III of the Clean Air Act Amendments of 1990. EPA plans to issue final regulations by December 2004, and is expected to require compliance by December 2007. The Department of Energy estimates that control of mercury emissions from coal-fired utility boilers will cost billions of dollars annually. Prior to installing a mercury control system, improved measurements of mercury emissions would allow EPA and the utility to make better decisions concerning control options. Real-time continuous monitoring of mercury would provide options for advanced process control feedback and for monitoring the performance of the control system, thus lowering the cost of mercury controls. Although a few mercury analyzers show promise for measuring elemental mercury, a reliable sampling system that allows these analyzers to measure total (particulate, vapor-phase) and speciated mercury continuously and in real time in the flue gas of coal-fired boilers is needed. Apogee is defining a new state-of-the-art in mercury measurement by developing a novel sample conditioning system (SCS) for the continuous real-time monitoring of mercury in flue gas from coal-fired boilers. The technical objective of the Phase II program is to finalize development of a field prototype SCS allowing commercially available CVAAS or CVAFS analyzers or an Apogee-built CVAAS analyzer to measure total mercury and to differentiate between particulate, elemental, and speciated mercury in coal-combustion flue gas. Performance of the SCS/analyzer will be evaluated during Phase II using EPA's Draft PS-12. Because CVAFS and CVAAS based analyzers detect only elemental mercury, the proposed SCS will provide three separate sample streams. In the first, flue gas is extracted and heated to thermally desorb mercury from the fly ash. All mercury is converted to elemental mercury in a reduction catalyst. In the vapor-phase sample lines, particulate is removed with an Apogee-built intertial separation system. In the total vapor-phase sample line, all vapor-phase mercury is converted to elemental mercury in a reduction catalyst. In the elemental mercury sample line, the oxidized mercury is removed in a HgCl2 removal module. In all sample lines, the gas is conditioned to remove interfering gases, dried, and stabilized prior to transport to an analyzer. Success during the Phase I program and enthusiastic support from the Electric Power Research Institute suggest that this technique is technically viable and preliminary economic studies suggest that it will be cost effective. Supplemental

Keywords:
small business, SBIR, monitoring, analytical, mercury, coal-fired utility boilers, air emissions, EPA.