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Proceedings Paper

A novel variable power diode laser sensor for harsh process monitoring
Author(s): William Von Drasek; Anna Pubill Melsió; Shawn Wehe; Mark Allen
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Paper Abstract

Industrial applications using tunable diode laser technology for process gas monitoring are often faced with technical challenges because of dynamic operating conditions in the presence of high particle densities and high temperature. Furthermore, issues related to alignment stability and maintenance requirements must be overcome for industry acceptance of the sensing technology. To address these technical challenges a novel near infrared tunable diode laser system for monitoring CO, H2O and gas temperature is presented. The system incorporates balanced ratiometric detection and a variable laser power delivery scheme allowing the launch laser power to vary between 2-248 mW while maintaining a constant reference power. Feedback control is used to adjust the level of laser power delivered to the process based on the light transmission through the measurement zone. Results are presented using the system on a 500 kW oxy-fuel pilot furnace with controlled particle injection to simulate industrial conditions in preparation for field test campaign measuring the off-gas of an electric arc (EAF) steel-melting furnace. For the industrial test, monitoring on the EAF process can be considered one of the harshest environments to perform a measurement with particle densities rising above 100 g/Nm3 and temperatures up to 1800°C. In addition, special requirements are needed to integrate the sensor into the process because of the high level of mechanical vibration, high and varying ambient temperatures, EMF interference sources, and protection against flying debris.

Paper Details

Date Published: 5 November 2005
PDF: 7 pages
Proc. SPIE 5998, Sensors for Harsh Environments II, 59980E (5 November 2005); doi: 10.1117/12.631803
Show Author Affiliations
William Von Drasek, American Air Liquide (United States)
Anna Pubill Melsió, Air Liquide (France)
Shawn Wehe, Physical Sciences, Inc. (United States)
Mark Allen, Physical Sciences, Inc. (United States)

Published in SPIE Proceedings Vol. 5998:
Sensors for Harsh Environments II
Anbo Wang, Editor(s)

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