Evolution of sulfur during pyrolysis of petroleum kerogens

Sulphur K edge spectroscopy was used to differentiate types of sulphur pres ent in petroleum asphaltenes and kerogens. A simplified model of the near e dge structure enabled quantification of the different sulphur forms. The ev olution of the sulphur edge following pyrolysis of kerogens confirms that t hiophenic sulphur is more stable than organic sulphide forms. Pyrite retain ed in the kerogens may partially transform to iron sulphate during air stor age. During pyrolysis FeS2 is regenerated and subsequently converted to FeS , contributing to the release of H2S. The results show that exchange betwee n organic and mineral forms of sulphur is limited.