The role of sulfur in the pyrolysis of kerogen

Sulfur plays an important role in the generation and evolution of hydrocarbon from organic matter. Here, a pyrolysis experiment in closed system was performed on Maoming oil shales kerogen (Type Ⅰ), Maoming oil shales kerogen added with sulfur ether and Maoming oil shales kerogen added with sulphur. The results suggest that the existence of sulfur can result in: (i) higher yield of hydrocarbons generated from the kerogen; (ii) decrease of the temperature for the maximum generation of heavy hydrocarbons (the C15+ fraction) by 20℃; (iii) decrease of the temperature for the maximum generation of the aromatics fraction by 40℃, and (iv) acceleration of the aromatization process. The pyrolysates from kerogen added with sulfur are similar to the heating products of the sulfur-rich kerogen as reported in the literatures. It seems that the sulfur catalysis is also an important factor that can make the sulfur-rich kerogen generate low-mature oil at the earlier diagenesis stage, except for the weakness of the C-S and S-S bonds.