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NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
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Evaluation of Passive FTIR to Determine Efficiency of Operating Industrial Flares
Karen N. T. Olson, P.E.
Texas Commission on Environmental Quality, Austin, Texas
Walt Crow
URS
Bob Spellicy
IMACC
Elevated flares are commonly used by petrochemical and refining facilities to abate emissions resulting from process vents and emission events. EPA has determined, based on previously flare testing, that under certain operating conditions (tip velocity and btu value of the waste gas) a flare should be expected to provide 98-99% destruction efficiency. Emissions are commonly estimated based on the waste gas flow rate and composition with an assumed 98-99% destruction efficiency. However, during actual flare operation there may be many conditions that affect flare efficiency as well as periods of time when actual operation is not within the EPA defined range. Some previous data indicates that under these conditions efficiency can deviate significantly from 98-99%.
The best information concerning flare efficiency would be from actual real-time measurements during flare operation. It has not been possible to measure flare efficiency of an operating flare because the flame is not enclosed. TCEQ, URS and IMACC have been evaluating passive FTIR as a possible method for determining real time actual flare efficiency. The intent of this project is to provide data and methodologies to be used to improve emission estimates for flares. The project involves:
- testing of an instrument to determine the capability of passive FTIR to provide the desired data quality for measurements of flare combustion and destruction efficiency, and estimated mass emission rates over a range of operating conditions; and
- gathering of combustion efficiencies, destruction efficiencies, total mass emissions and, to the extent possible, speciated emissions from flares operating under a variety of conditions.