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Title: Evaluation of near-infrared tunable diode lasers for detection of transient emissions from a rotary kiln.

Near-infrared tunable diode lasers (TDLs) were evaluated for their suitability as fast-response combustion performance indicators during tests at the U.S. Environmental Protection Agency's pilot-scale Rotary Kiln Incinerator Simulator (RKIS) facility. Transient emissions (i.e., 'puffs') of various magnitudes and duration were generated by injecting a mixture of toluene and methylene chloride into the rotary kiln, through use of a computer-controlled liquid gun or by ram-loading containers of the waste surrogate adsorbed onto corncob. Two wavelength-modulated TDLs that span carbon monoxide (CO) and methane absorption lines at 1.57 and 1.65 pm, respectively, provided information on these species as well as total laser transmittance (an indicator of soot loading). Fiber-optic cables transmitted the laser light from the remotely situated TDLs to two line-of-sight measurement locations. In addition, the TDLs were used with a multi-pass optical cell to perform more sensitive extractive measurements. Over the optical pathlength available in this facility, in situ measurements of methane down to a concentration of {approx} 100 ppm were demonstrated during non-sooty conditions. CO could not be reliably quantified in situ, even at concentrations as high as 0.7%, due to the combination of weak absorption line strength and interfering water and carbon-dioxide hot-bands. The soot produced during themore » toluene/methylene chloride puffs typically attenuated over 90% of the TDL laser beam, preventing effective in situ TDL measurements during the puffs. In contrast, the extractive TDL measurements demonstrated good accuracy and sensitivity for both methane and CO under all reactor conditions. Furthermore, the in situ laser transmittance profiles during the puffs provided new insights into the composition of the puffs as a function of puff magnitude and residence time.« less
Authors:
; ; ;  [1] ;  [1]
  1. (U.S. Environmental Protection Agency, Research Triangle Park, NC)
Publication Date:
OSTI Identifier:
918248
Report Number(s):
SAND2003-8721
TRN: US200818%%326
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Research Org:
Sandia National Laboratories
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; CARBON MONOXIDE; DETECTION; ENVIRONMENTAL PROTECTION; EVALUATION; LASERS; METHANE; METHYLENE CHLORIDE; TRANSIENTS