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Title: Microwave plasma monitoring system for the elemental composition analysis of high temperature process streams

Abstract

Microwave-induced plasma for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, high temperature capability refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury. The invention may be incorporated into a high temperature process device and implemented in situ for example, such as with a DC graphite electrode plasma arc furnace. The invention further provides a system for the elemental analysis of process streams by removing particulate and/or droplet samples therefrom and entraining such samples in the gas flow which passes through the plasma flame. Introduction of and entraining samples in the gas flowmore » may be facilitated by a suction pump, regulating gas flow, gravity or combinations thereof.« less

Inventors:
 [1];  [2];  [3];  [4]
  1. Bedford, MA
  2. Chestnuthill, MA
  3. Newtown Square, PA
  4. Kennewick, WA
Issue Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
OSTI Identifier:
871157
Patent Number(s):
5671045
Assignee:
Masachusetts Institute of Technology (Cambridge, MA)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
DOE Contract Number:  
AC06-76RL01830
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
microwave; plasma; monitoring; elemental; composition; analysis; temperature; process; streams; microwave-induced; continuous; time; trace; element; harsh; variable; conditions; sensor; source; power; energy; shorted; waveguide; conductive; capability; refractory; material; communicating; generate; constructed; robust; hot; hostile; environment; aperture; passage; gases; analyzed; spectrometer; connected; receive; light; provision; situ; calibration; disperses; computer; capable; quantitative; measurements; desired; elements; heavy; metals; lead; mercury; incorporated; device; implemented; example; dc; graphite; electrode; furnace; provides; removing; particulate; droplet; samples; therefrom; entraining; gas; flow; passes; flame; introduction; facilitated; suction; pump; regulating; gravity; combinations; removing particulate; process streams; plasma monitoring; trace element; heavy metal; refractory material; process stream; gas flow; microwave energy; heavy metals; microwave plasma; wave energy; hostile environment; temperature process; receive light; power microwave; spectrometer disperses; quantitative measurements; situ calibration; shorted waveguide; quantitative measure; composition analysis; microwave-induced plasma; elemental composition; variable conditions; time trace; element monitoring; quantitative measurement; electrode plasma; /356/333/

Citation Formats

Woskov, Paul P, Cohn, Daniel R, Titus, Charles H, and Surma, Jeffrey E. Microwave plasma monitoring system for the elemental composition analysis of high temperature process streams. United States: N. p., 1997. Web.
Woskov, Paul P, Cohn, Daniel R, Titus, Charles H, & Surma, Jeffrey E. Microwave plasma monitoring system for the elemental composition analysis of high temperature process streams. United States.
Woskov, Paul P, Cohn, Daniel R, Titus, Charles H, and Surma, Jeffrey E. Wed . "Microwave plasma monitoring system for the elemental composition analysis of high temperature process streams". United States. https://www.osti.gov/servlets/purl/871157.
@article{osti_871157,
title = {Microwave plasma monitoring system for the elemental composition analysis of high temperature process streams},
author = {Woskov, Paul P and Cohn, Daniel R and Titus, Charles H and Surma, Jeffrey E},
abstractNote = {Microwave-induced plasma for continuous, real time trace element monitoring under harsh and variable conditions. The sensor includes a source of high power microwave energy and a shorted waveguide made of a microwave conductive, high temperature capability refractory material communicating with the source of the microwave energy to generate a plasma. The high power waveguide is constructed to be robust in a hot, hostile environment. It includes an aperture for the passage of gases to be analyzed and a spectrometer is connected to receive light from the plasma. Provision is made for real time in situ calibration. The spectrometer disperses the light, which is then analyzed by a computer. The sensor is capable of making continuous, real time quantitative measurements of desired elements, such as the heavy metals lead and mercury. The invention may be incorporated into a high temperature process device and implemented in situ for example, such as with a DC graphite electrode plasma arc furnace. The invention further provides a system for the elemental analysis of process streams by removing particulate and/or droplet samples therefrom and entraining such samples in the gas flow which passes through the plasma flame. Introduction of and entraining samples in the gas flow may be facilitated by a suction pump, regulating gas flow, gravity or combinations thereof.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1997},
month = {1}
}

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Works referenced in this record:

Determination of trace impurities in argon by microwave induced excitation
journal, July 1970


Microwave Discharge Cavities Operating at 2450 MHz
journal, March 1965


Microwave Plasma Emission Spectrometry
journal, June 1976


A novel microwave plasma cavity assembly for atomic emission spectrometry
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Microwave-Supported Discharges
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Atomic emission sources for solution spectrochemistry
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Application of weakly ionized plasmas for materials sampling and analysis
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Design concepts for strip-line microwave spectrochemical sources
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High-Power Microwave-Induced Plasma Source for Trace Element Analysis
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Comparison of microwave-induced plasma sources
journal, January 1991


A Review of Instrumentation Used to Generate Microwave-Induced Plasmas
journal, November 1984