Infrared Analysis of Particulates by FT-IR Emission/Transmission Spectroscopy

Abstract

In this paper we report on a new method for the on-line chemical characterization of gas-suspended particulate and liquid droplet streams. The method is a combination of emission and transmission (E/T) spectroscopy performed using a Fourier transform infrared (FT-IR) spectrometer and a cell which allows analysis of room-temperature particulates surrounded by hot walls. The method was based on the discovery that the spectrum of radiation coming from such particles contained structure corresponding to the infrared absorption spectrum of the particulates. It was determined that the observed energy was wall radiation which reaches the detector after refraction by, and transmission through the particles. The shape of the observed spectrum relative to that of the wall spectrum is reduced at the absorption bands of the particulates. The general concepts of the E/T method were validated by samples with sizes varying from a few to several hundred microns with varying optical properties. For solids, excellent results were achieved for composition measurements. For a sample of known particle size, quantitative absorbance spectra were obtained from the E/T spectra with the use of a model based on ray optics. The spectra were in good quantitative agreement with absorbance spectra derived by the KBr pellet method for the same sample thickness. The E/T derived spectra were somewhat noisier than the KBr pellet spectra, but were free of Christiansen effect band distortions and scattering contributions. The E/T method has the additional advantage of requiring little or no sample preparation.

Keywords

Analysis for solid particulates Emission spectroscopy Infrared Instrumentation emission spectroscopy

Get full access to this article

View all access options for this article.

References

Schiedt

and Reinwein

, Z. Naturf. 7b, 270 (1952).

Stimson

M. M.

and O'Donnell

M. J.

, J. Amer. Chem. Soc. 74, 1805 (1952).

Solomon

P. R.

and Carangelo

R. M.

, Fuel 61, 663 (1982).

McClelland

J. F.

, Anal. Chem. 55, 89A (1983).

Vidrine

W. D.

, Fourier Transform Infrared Spectroscopy 3, 125 (1982).

Vidrine

W. D.

, Appl. Spectrosc. 34, 214 (1980).

Fuller

M. P.

and Griffiths

P. R.

, Anal. Chem. 50, 1906 (1978).

Fuller

M. P.

and Griffiths

P. R.

, Appl. Spectrosc. 34, 533 (1980).

Yeboah

S. A.

Wang

S. S.

, and Griffiths

P. R.

, Appl. Spectrosc. 38, 259 (1984).

10.

Fuller

M. P.

Hamadeh

I. M.

Griffiths

P. R.

, and Lowenhaupt

D. E.

, Fuel 61, 529 (1982).

11.

Solomon

P. R.

and Hamblen

D. G.

, “Coal Gasification Reactions with On-Line In-Situ FT-IR Analysis,” Quarterly Reports, DOE Contract No. DE-AC21-81FE05122 (1981).

12.

Solomon

P. R.

and Hamblen

D. G.

, “An Investigation of Vaporization and Devolatilization of Coal/Water Mixtures,” Quarterly Reports, DOE Contract No. DE-AC22-82PC50254 (1982).

13.

Solomon

P. R.

Hamblen

D. G.

Carangelo

R. M.

, and Krause

J. L.

, 19th Symposium (Int) on Combustion (The Combustion Institute, Pittsburgh, Pennsylvania, 1982), p. 1139.

14.

Solomon

P. R.

Hamblen

D. G.

, and Carangelo

R. M.

, “Applications of FT-IR in Fuel Science,” ACS Symposium Series 205, 77 (1981).

15.

Solomon

P. R.

, “Experiments and Modeling of Multi-Component Fuel Behavior in Combustion,” Air Force Contract No. F33615-83-C-55139, Final Report for Phase I (1984).

16.

Solomon

P. R.

Hamblen

D. G.

, and Carangelo

R. M.

, “Analytical Pyrolysis of Coal Using FT-IR,” in Analytical Pyrolysis, Voorhees

K. J.

, Ed. (Butterworth, London, 1984), p. 121.

17.

Solomon

P. R.

and Hamblen

D. G.

, “Measurement and Theory of Coal Pyrolysis Kinetics in an Entrained Flow Reactor,” EPRI Final Report for Project No. RP 1654-8 (1983).

18.

Ottensen

D. K.

and Thome

L. R.

, Proceedings of the 1983 International Conference on Coal Science, Pittsburgh, Pennsylvania (1983), p. 621.

19.

Ottensen

D. K.

and Stephenson

D. A.

, Combustion and Flame 46, 95 (1982).

20.

Hamblen

D. G.

Best

P. E.

Carangelo

R. M.

, and Solomon

P. R.

, “Combustion Coal Particle Temperatures by FT-IR Spectroscopy,” Final Report for NSF Grant No. CPE-83-60666 (1984).

21.

Best

P. E.

Carangelo

R. M.

, and Solomon

P. R.

, ACS Div. of Fuel Chemistry Preprints 29, #6, 249 (1984).

22.

Solomon

P. R.

Hamblen

D. G.

Carangelo

R. M.

Markham

J. R.

, and Chaffee

M. R.

, ACS Div. of Fuel Chemistry Preprints 30, #1, 266 (1985).

23.

Solomon

P. R.

Serio

M. A.

Carangelo

R. M.

, and Markham

J. R.

, ACS Div. of Fuel Chemistry Preprints 30, #1, 1 (1985).

24.

Solomon

P. R.

Serio

M. A.

Carangelo

R. M.

, and Markham

J. R.

, Fuel 65, 182 (1986).

25.

Best

P. E.

Carangelo

R. M.

Markham

J. R.

, and Solomon

P. R.

, “FT-IR Emission—Absorption Measurements from Coal and Char: Temperature and Emittance,” accepted for publication in Combustion and Flame (1986).

26.

Bohren

C. E.

and Huffman

D. R.

, Absorption and Scattering of Light by Small Particles (John Wiley and Sons, New York, 1983).

27.

Laufer

Huneke

J. T.

Royce

B. S. H.

, and Teng

Y. C.

, Appl. Phys. Lett. 37, 517 (1980).

28.

Gumprecht

R. O.

and Sliepcevich

C. M.

, J. Phys. Chem. 57, 90 (1953).

29.

Brewster

M. Q.

and Kunitomo

, Trans. ASME 106, 678 (1984).

30.

Solomon

P. R.

Carangelo

R. M.

Best

P. E.

, and Hamblen

D. G.

, “Analysis of Particle Composition, Size and Temperature by FT-IR Emission/Transmission Spectrocopy,” ACS Div. of Fuel Chemistry Preprints 31, (1986).