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Abstract

Several laser-based techniques are being developed to provide in situ determinations of size, velocity, and elemental composition for individual particulates in combustion environments. Emphasis is placed on composition measurements using laser spark spectroscopy, and data for particulates entrained in gaseous flows are presented. Size and velocity of individual particles are determined by a colinear two-color laser scattering technique. Laser sparks (high-temperature plasmas) are produced from single particles with the use of a Q-switched Nd:YAG laser, and time-resolved emission spectra are observed. Results indicate a high sensitivity of the technique to mineral matter in coal particles. The detection of numerous constituent species is demonstrated, and trends observed in elemental distribution are in agreement with x-ray fluorescence measurements. Initial semi-quantitative results are compared with standard chemical analyses of the bulk material.

Keywords

Analyses coal particles Emission spectroscopy Lasers Nd:YAG Methods analytical Laser spark

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References

Schmieder

R. W.

, Techniques and Applications of Laser Spark Spectroscopy, Sandia National Laboratories Report SAND83–8618 (1983).

Radziemski

L. J.

and Loree

T. R.

, J. Plasma Chem. Plasma Proc. 1, 281 (1981).

Wang

J. C. F.

and Hencken

K. R.

, Applied Opt. 25, 653 (1986).

Ottesen

D. K.

, “In Situ Real-Time Analysis of Particulates Using Laser Spark Spectroscopy,” in Proceedings of the International Conference on Coal Science, Moulijn

J. A.

, Ed. (Elsevier, New York, 1987), p. 777.

Cremers

D. A.

and Radziemski

L. J.

, “Laser Plasmas for Chemical Analysis,” in Laser Spectroscopy and Its Applications, Radziemski

L. J.

Solarz

R. W.

, and Paisner

J. A.

, Eds. (Marcel Dekker, New York, 1987), Chap. 5.

Laqua

, “Analytical Spectroscopy Using Laser Atomizers,” in Analytical Laser Spectroscopy, Omenetto

, Ed. (Wiley, New York, 1979), Chap. 2.

Mika

and Torok

, Analytical Emission Spectroscopy (Butterworth, London, 1974).

Boumans

P. W. J. M.

, Theory of Spectrochemical Analysis (Hilger, London, 1966).

Loree

T. R.

and Radziemski

L. J.

, “Laser-Induced Breakdown Spectroscopy: Detecting Sodium and Potassium in Coal Gasifiers,” in Proceedings of the 1981 Symposium on Instrument Control Fossil Energy Progress, ANL81-62/Conf-810607 (Argonne National Laboratory Press, Argonne, Illinois, 1982), p. 768.

10.

Holve

J. D.

and Self

S. A.

, J. Appl. Opt. 18, 1632 (1979).

11.

Radziemski

L. J.

Loree

T. R.

Cremers

D. A.

, and Hoffman

N. M.

, Anal. Chem. 55, 1246 (1983).

12.

Archontaki

H. A.

and Crouch

S. R.

, Appl. Spectrosc. 42, 741 (1988).

13.

Meggers

W. F.

Corliss

C. H.

, and Scribner

B. D.

, Tables of Spectral-Line Intensities, Part I, NBS-MN-145 (National Institute of Standards and Technology, Gaithersburg, Maryland, 1975).

14.

Wiese

W. L.

and Martin

G. A.

, Wavelengths and Transition Probabilities for Atoms and Atomic Ions, NSRDS-NBS 68 (National Institute of Standards and Technology, Gaithersburg, Maryland, 1980).

15.

Baldwin

J. M.

, Appl. Spectrosc. 24, 429 (1970).

16.

Cerrai

and Trucco

, Energia Nucleare 15, 581 (1968).

17.

Adrain

R. S.

and Watson

, J. Phys. D: Appl. Phys. 17, 1915 (1984).

18.

Nissen

, Sandia National Laboratories, private communication (1987).

19.

Sarofim

A. F.

Howard

J. B.

, and Padia

A. S.

, Comb. Sci. and Tech. 16, 187 (1977).

20.

Quann

R. J.

and Sarofim

A. F.

, Fuel 65, 40 (1986).

Real-Time Laser Spark Spectroscopy of Particulates in Combustion Environments

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