Characterization of Dachengzi Oil Shale Fast Pyrolysis by Curie-Point Pyrolysis-Gc-MS

Abstract

Fast pyrolysis of a Dachengzi oil shale sample was studied using a Curie-point pyrolyzer, the pyrolysis products were characterized online by gas chromatography-mass spectroscopy. Nine different Curie-point temperatures were chosen to investigate product distribution regularities. Hydrocarbons were the major components of the fast pyrolysis products of oil shale. n-Alkanes were generated at all the nine temperatures, while cycloalkanes only appeared at the temperatures above 485 °C. Branched alkanes were seldom produced at all the temperature points because of the bond cleavage at the branch point. Alkenes and aromatic compounds began to be formed at 386 °C and 423 °C separately, and their molecule sizes decreased with increasing pyrolysis temperature. Various oxygen-containing compounds, including ketones, acids, alcohols, esters and phenols, were identified in the shale oil components, indicating the wide existence of oxygen-containing functional groups.

Structural characterization of Huadian oil shale kerogen by using 13C DP/MAS NMR

“…Therefore, the aliphatic chains contain slightly less than 20 carbon atoms on average. This is consistent with the results of fast pyrolysis experiments, which show that at 600-700 °C, most alkanes and alkenes in the shale oil products contain around 20 carbon atoms [40]. The Cn values reported in previous studies on Huadian oil shale kerogen [16,19,37,38] were higher than the Cn value obtained in the current research because CP underestimated the aromaticity and the average chain length was defined differently.…”

“…The average number of carbons per aromatic cluster (C) was defined on the assumption that the aromatic cluster size does not exceed two rings. Since Huadian oil shale kerogen mainly possesses aromatic clusters of 1-2 rings referring to the fast pyrolysis studies [40,42], the C value calculated by the equation given in Table 3 is accurate enough. The C value of 8.5 indicates that there are slightly more naphthalene units in this kerogen than benzene units.…”

“…Quaternary aliphatic carbon and C = C groups have been introduced into several previously proposed kerogen models [19,38,39]. However, the fast pyrolysis study of Huadian oil shale by Huang et al [40] shows that no adamantane-like structures exist in the pyrolysis products and almost all alkenes generated are α-alkenes, indicating that the content of quaternary aliphatic carbon and C = C groups in the kerogen is negligible. Thus, no carbon resonance was assigned to them.…”

The effect of pyrolysis conditions on the composition of Chinese Jimsar shale oil using FT-IR, 1H-NMR and 13C-NMR techniques

“…Compared with -CH 2 , -CH 3 and C=C functional groups, the relative content of oxygen-containing functional groups (C-O and C=O) is comparatively small. However, Huang et al [39] reported the oxygenated compounds to be the main component of non-hydrocarbons of shale oil. Moreover, Wang et al [28] found that the relative content of C-O functional groups was much greater than that of C=O functional groups.…”

“…It can be seen from Table 5 that the oxidation-containing compounds are little affected by the process. This is because the proportion of oxygenated compounds in shale oil is determined by the maturity of oil shale [39]. Furthermore, some researchers [20] have found that oxygen-containing compounds are not stable when heated.…”