In this article, we present data on the distribution of sulfur in Estonian kukersite shale oil. It was found that the highest concentration of sulfur is present in the fractions boiling between about 150 and 190°C. Also, we studied the effect of N2, N2/steam, CO2, and CO2/steam environments on the concentrations of some sulfur compounds in shale oil. The results show that thiophenic compounds comprise most of the sulfur compounds in crude kukersite shale oil. Furthermore, CO2 increased the concentration of some of the identified sulfur compounds in the shale oil as compared to N2. The presence of steam significantly increased the concentration of sulfur compounds in the oil as compared to dry sweeping gases. This was also supported by investigation of the release of H2S and SO2 gases during the pyrolysis of oil shale in which steam enhanced the release of sulfurous gases. The presence of steam not only enhances the release of sulfur compounds from oil shale, but also causes it to occur at lower temperatures.

A kukersite oil shale sample from Estonia was pyrolyzed using a Fischer assay method under N2, N2/steam, CO2 and CO2/steam environments. The thermal behavior of the oil shale sample was also studied using TGA and DSC with similar conditions. Also, several properties of produced oils were measured and FTIR analysis was carried out to compare the molecular structure of the derived oils. The presence of steam increased the liquid and gaseous yields, and also caused a greater weight loss in the oil shale. The pyrolysis tests in both the CO2 and N2 atmospheres produced oils with relatively similar properties however, the molecular structure was different.

Studying the evolution of gas during the decomposition process of oil shale provides information about the changes of gas composition and understand the mechanism of pyrolysis process. A few number of studies focused on using CO2 atmosphere to observe the effect of sweep gas on pyrolysis products. Fischer assay method was used to analyze the pyrolysis of Estonian kukersite oil shale under CO2, CO2/steam, N2 and N2/steam. The gaseous products were collected offline using a sample bag. Gas chromatography was performed to investigate the evolution of C1-C3 gases, H2, CO2 and CO. Subsequently, the results from each test were analyzed and compared. Our results show that in comparison with N2, pyrolysis in CO2 increased the production of alkanes and hydrocarbon gases. Also, generation of CH4 and CO gases were enhanced under CO2, while composition of H2 did not significantly change in the gaseous products for both environments. For the tests in presence of steam, the results show that unlike the N2 atmosphere, CO2/steam decreased the production of total hydrocarbons, H2, CO2 and CO.

Studying the evolution of gas during the decomposition process of oil shale provides information about the changes of its composition, as well as an understanding of the mechanism of the pyrolysis process. Earlier mainly the CO 2 atmosphere was used to observe the effect of the sweep gas on the production of pyrolysis products. In the current study, the Fischer assay method was used to analyze the pyrolysis of Estonian kukersite oil shale with CO 2 , CO 2 /steam, N 2 and N 2 /steam sweep gases. The gaseous products were collected offline using a sample bag. Gas chromatography (GC) was performed to investigate the evolution of C 1 -C 3 gases, H 2 , CO 2 and CO. Subsequently, the results from each test were analyzed and compared. It was shown that in comparison with N 2 , pyrolysis in CO 2 increased the production of alkanes and hydrocarbon (HC) gases. Also, the generation of CH 4 and CO gases was enhanced with CO 2 , while the concentration of H 2 in the pyrolysis gas did not significantly change with either environment. The tests carried out in the presence of steam showed that unlike the N 2 atmosphere, CO 2 /steam decreased the production of total hydrocarbons, H 2 , CO 2 and CO.

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