A continuous isokinetic gas/mist sampler for flue stream extractive analysis
Title:
A continuous isokinetic gas/mist sampler for flue stream extractive analysis
Author:
Lucero, Daniel P. Kolakowski, Jan E.
Appeared in:
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering
Paging:
Volume 21 (1986) nr. 7 pages 639-680
Year:
1986-10
Contents:
A special-purpose stream sampler is required for the automated and continuous extractive analysis of saturated mist-laden flue gas streams. Isokinetic sampling is essential for those applications in which the analyte molecules are miscible in or otherwise associated with the mist droplets. Essentially, continuous isokinetic sampling is accomplished over a 30- to 60-ft/s flue stream velocity range by a heated sampling probe through which a large sample (∼50 to 100 L/min) is pumped solely by the flue stream dynamic pressure and returned directly to the flue. The probe geometry and dimensions are configured to permit the probe pressure losses experienced by the sample stream to vary in proportion to the flue stream dynamic pressure, i.e., flue stream velocity, to maintain an isokinetic condition at the probe entrance. As the sample flows through the probe, it is heated, and the mist droplets are vaporized by the energy from the probe wall, which is maintained at 340 °F. Near the probe exit and prior to return of the sample stream to the flue, a second probe, located in the sample stream and operating independently of the heated sampling probe, extracts continuously a small fraction (∼1 to 2 percent) of the sample stream for further processing, if required, and subsequent analysis. Because the analyte molecules at the heated probe exit exist in gas phase, isokinetic sample extraction is not required for operation of the second probe. Efficient sample transport through the heated probe is attained by vaporization of the mist droplets and liquid phase altogether, which precludes the formation of absorbing wetted-wall surfaces.
Journal description