Chemistry and Chemical Biology ETDs

Publication Date

11-23-1977

Abstract

The fusion of oil shales with eutectic mixtures of inorganic salts was studied with the objective of finding a chemical means of releasing the organic material either at a lower temperature or with a lower empirical activation energy (Ea). Experimental techniques by which the pyrolysis of oil shale was studied were thermogravimetry (TG), evolved gas detection (EGD), and pyrolysis/thin-layer chromatography (TLC). The following fused salts were investigated (ratios in mo1%): LiCO3/Na2co3/K2CO3, 43.5/31.5/25.0; KSCN/NaSCN, 73.75/26.25; KSCN/­NaSCN, 70/30; Na2SO4/K2SO4/ZnSO4, 29.1/30.2/40.7; NaCl/Na2CO3/NaOH, 7.8/6.4/85.8; and K2CrO4/KOH/LiOH, 6/69/25. The last two mixtures were extremely difficult to handle and were unsuitable for use in oil-shale pyrolyses. Of the others, only the carbonate eutectic showed any difference in pyrolysis of oil shale with the fused salt as compared with pyrolysis of the oil shale alone. For a 50 gallon-per­ton (gpt) oil shale, this eutectic effected increased product evolution only above 675° C; however, for a 22-gpt oil shale, increased product release was observed starting at about 400 °C. These results are thought to be due to differences in the mineral content of the shales. To determine the effect of the carbonate eutectic on the silicate minerals, pyrolyses of this mixture with analcime, kaolin, and bentonite were studied. In all cases, there was increased product evolution in the presence of the eutectic; the increase began in the region of 400 to 450°C on the TG curves. Empirical Ea's for oil-shale pyrolysis calculated from EGD curves were found to be in the range of 35 to 49 kcal mole -1 for temperatures of 350 to 390° C and 19 to 31 kcal mole-1 above 390 (or 400) ° C. The presence of eutectics had little effect on the Ea values except in the case of pyrolysis of the 22-gpt oil shale with the carbonate eutectic. The technique of pyrolysis-TLC was used to enable separation of pyrolysis products according to temperature fractions. Problems encountered with solvent impurities, small sample size, and poor product elution resulted in disappointingly little data from this technique. TG analyses in a CO2 atmosphere were performed on two oil shales. The only effect of the CO2 is the suppression of carbonate decomposition. TG was investigated as a method for determining oil yield of oil shales. TG curves were obtained for a series of Green River Formation oil shales of varying density. The samples were heated at a rate of 10°C/min in a helium atmosphere. The weight loss up to 600°C is predominantly a result of the release of organic material; the weight loss above 600°C is primarily due to mineral decomposition. TG curves were also obtained for the available pure minerals known to be present in oil shales.

Language

English

Document Type

Thesis

Degree Name

Chemistry

Level of Degree

Masters

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Edward A. Walters

Second Committee Member

E. Dan Loughran

Third Committee Member

Roy Dudley Caton Jr.

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