Microwave plasma torch continuous emissions monitor
- Massachusettes Institute of Technology, Cambridge, MA (United States)
The emissions of toxic and heavy metals in the exhaust gas streams of furnaces used for waste processing, industrial manufacturing, and power production can pose an unacceptable safety and health risk on local communities and the environment. Therefore, strictly controlling such emissions is an important and critical task. In order to make such control practical and enforceable, a need exists for continuous emission diagnostics of vapors and particulates in the off gas stream of furnaces. Currently, the Environmental Protection Agency has determined a need for monitoring the emissions of twelve metals (Ag, As, Ba, Be, Cd, Cr, Hg, Ni, Pb, Sb, Se, Tl). A device capable of such a task, a microwave plasma torch system for metal particulate atomic emission spectroscopy in a high temperature furnace environment, is under development at MIT. Implementation on a pilot scale DC graphite arc furnace at MIT used for investigation of treatment of wastes at Department of Energy sites is under progress. Microwave torch laboratory tests in nitrogen and ambient air gas flows laden with furnace particulates have demonstrated plasma robustness and high sensitivity to trace elements. Plasma torch temperatures of about 5000{degrees}C has been spectroscopically determined in the laboratory. Mass detection limits in the sub-nanogram range and concentration limits of < 1 ppb have been achieved for many metals. Real time, in situ absolute calibration techniques have been tested requiring only sub-microgram calibration mass quantities. Various calibration sample insertion techniques are under investigation, and the results will be presented.
- OSTI ID:
- 375033
- Report Number(s):
- CONF-9304297--
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
- Country of Publication:
- United States
- Language:
- English
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