Development of Optical Technologies for Monitoring Moisture and Particulate in Geothermal Steam

Partin, J. K.

Idaho National Laboratory

关键词: Particulates;    Water Vapor;    15 - Geothermal Energy;    Absorption;    Lasers;   

DOI  :  10.2172/911675
RP-ID  :  INL/EXT-06-11705
RP-ID  :  DE-AC07-99ID-13727
RP-ID  :  911675

美国|英语

来源: UNT Digital Library

【 摘 要 】

The results of an investigation directed at evaluating the feasibility of using optical measurements for the real-time monitoring moisture and particulate in geothermal steam is described. The measurements exploit new technologies that have been developed for the telecommunications industry and includes new solid state laser devices, large-bandwidth, high-sensitivity detectors and low loss optical fiber compo-nents. In particular, the design, fabrication, and in-plant testing of an optical steam monitor for the detection of moisture is presented. The measurement principle is based upon the selective absorption of infrared energy in response to the presence of moisture. Typically, two wavelengths are used in the measurements: a wavelength that is strongly absorbed by water and a reference wavelength that is minimally influenced by water and steam which serves as a reference to correct for particulate or droplet scattering. The two wavelengths are chosen to be as close as possible in order to more effectively correct for scattering effects. The basic instrumentation platform developed for the in-situ monitoring of steam moisture can be modified and used to perform other measurements of interest to plant operators. An upgrade that will allow the instrument to be used for the sensitive detection of particulate in process streams has been investigated. The new monitor design involves the use of laser diodes that are much less sensitive to water and water vapor and more sensitive to scattering phenomena, as well as new processing techniques to recover these signals. The design reduces the averaging time and sampling volume, while increasing the laser probe power, enhancing particulate detection sensitivity. The design concept and initial laboratory experiments with this system are also reported.