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Title: A CAVITY RING-DOWN SPECTROSCOPY MERCURY CONTINUOUS EMISSION MONITOR

Technical Report ·
DOI:https://doi.org/10.2172/823019· OSTI ID:823019

The work performed during this quarter by SRD scientists and engineers focused on a number of tasks. The initial acquisition of some hardware needed and the actual construction of the sampling system have begun. This sampling system will contain the pyrolysis oven to atomize the sample gas stream needed for total gaseous mercury measurements, the CRD cavity to acquire the ring-down signal needed to obtain the mercury concentration, various tubing, and temperature and pressure measurement equipment. The amount of tubing and valves have been cut to a minimum to try and reduce the resident time the sample flue gas stream is in the sampling system and minimize the possibility that the gases in the sample gas stream will react with the elements of the sampling system and change the component mixture contained in the flue gas. In an effort to minimize the equipment that needs to be close to the actual sampling port, SRD scientists decided to fiber optically couple the laser to the CRD cavity. However, the ultra-violet (UV) light needed for the mercury transition presents a problem as fiber optics can be solarized by the UV radiation thereby changing the transmission characteristics. SRD has obtained a solarization-resistant fiber. SRD scientists were then able to couple the UV laser light into the fiber and inject the output of the fiber into the CRD cavity and obtain a ring-down signal. Long-term effects of the UV radiation on the fiber optic are being monitored to detect any change in the transmission of the laser light to the cavity. Additional requirements of the mercury CRD monitor will be to not only monitor the mercury concentration continuously but also perform the measurements over extended periods of time. SRD has extended some previously performed shorter-term studies to longer time intervals. The results of these initial long-term studies are very promising.

Research Organization:
Sensor Research and Development Corporation (US)
Sponsoring Organization:
(US)
DOE Contract Number:
FC26-01NT41221
OSTI ID:
823019
Resource Relation:
Other Information: PBD: 30 Sep 2003
Country of Publication:
United States
Language:
English