Publication Date

7-1985

Advisor(s) - Committee Chair

John Reasoner, John Riley, Gordon Wilson Jr.

Degree Program

Department of Chemistry

Degree Type

Master of Science

Abstract

Samples of four different Thai lignites were utilized to study the effects of ceiling temperature and heating rate on the overall yield and product distribution by the technique of analytical pyrolysis (pyrolysis-gas chromatography). Ceiling temperatures of 450°, 550°, 650°, 750°, 850°, and 950°C, a heating rate of 500°C/sec and pyrolysis intervals of 20 seconds were investigated. The results were reported in terms of percentage high-volatile product and low-volatile product fraction, weight-loss (% by weight), and total yield (counts per milligram). One sample which showed the highest sensitivity to changing ceiling temperature was selected to study the effect of heating rate on overall yield and product distribution. Heating rates of 500°C/sec and 100°C/sec (for an interval of 20 seconds) and 500°C/sec for one minute and 300°C/min for two minutes were employed in the study, at a ceiling temperature of 750°C.

The results of the above investigation may be summarized as follows:

  1. All four samples are lignite A (rank) but give different pyrograms as a result of differences in maceral concentrations and chemical structure of each of the coals.

  2. The total yield, high-volatile product, and weight-loss increase with increasing ceiling temperatures.

  3. Heating rates in the range studied have no significant effect on the total yield and product distribution.

  4. High -volatile product yield increases with increasing pyrolysis interval because of secondary cracking reactions but the overall product yield remains essentially constant.

Disciplines

Chemistry | Physical Sciences and Mathematics

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