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

Patent ·
OSTI ID:871157
 [1];  [2];  [3];  [4]
  1. Bedford, MA
  2. Chestnuthill, MA
  3. Newtown Square, PA
  4. Kennewick, WA
+ Show Author Affiliations
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.
Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA
DOE Contract Number:
AC06-76RL01830
Assignee:
Masachusetts Institute of Technology (Cambridge, MA)
Patent Number(s):
US 5671045
OSTI ID:
871157
Country of Publication:
United States
Language:
English

References (14)

An assessment of a microwave-induced plasma generated in argon with a cylindrical TM010 cavity as an excitation source for emission spectrometric analysis of solutions journal January 1978
Annular-shaped microwave-induced nitrogen plasma at atmospheric pressure for emission spectrometry of solutions. journal January 1991
Atomic emission sources for solution spectrochemistry journal August 1986
Atomic emission spectrometry of solid samples with laser vaporization-microwave induced plasma system journal October 1980
Microwave Plasma Emission Spectrometry journal June 1976
High-Power Microwave-Induced Plasma Source for Trace Element Analysis journal April 1990
A novel microwave plasma cavity assembly for atomic emission spectrometry journal September 1992
A Review of Instrumentation Used to Generate Microwave-Induced Plasmas journal November 1984
Comparison of microwave-induced plasma sources journal January 1991
Determination of trace impurities in argon by microwave induced excitation journal July 1970
Application of weakly ionized plasmas for materials sampling and analysis journal January 1991
Design concepts for strip-line microwave spectrochemical sources journal December 1990
Microwave Discharge Cavities Operating at 2450 MHz journal March 1965
Microwave-Supported Discharges journal July 1981

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