An interfacing system to sample total mercury emissions in source streams and suitably condition, dilute, and transport the sample to a mercury measuring instrument was designed, fabricated, and tested. The system consists of three components: a conditioner, a diluter, and a pump module. The conditioner contains a furnace to thermally decompose compounds at temperatures up to 1000C and a liquid scrubbing system to remove particulates and interfering gases, such as sulfur dioxide and nitrogen dioxide. The diluter module is used at sources where mercury levels are above the calibration range of the measuring instrument. The pump module draws the sample through the system, exhausts the waste scrubber liquid, and maintains a constant pressure in the analyzer. Field tests were conducted at a coal-fired power plant. Good correlation was obtained between the interface/photomatic analyzer and a reference manual procedure. Instrumental results ranged from 1.74 to 6.96 micrograms/cu m, with mean value of 4.23 micrograms/cu m; reference method results varied from 1.60 to 7.25 micrograms/cu m, with a mean value of 4.66 micrograms/cu m.

EPA Project Officer: Roy L. Bennett, Emissions Measurement and Characterization Division. Prepared by Geomet, Inc. under Contract No. 68-02-1789. "August 1978."