The kinetic modeling of oil cracking by hydrothermal pyrolysis experiments

The kinetic modeling of oil cracking by hydrothermal pyrolysis experiments using a Japanese oil, derived from type II kerogen, is reported here. Pyrol ysis experiments were carried out in the temperature range from 370 to 410 degrees C and the time range from zero to 384 h. The chemical structural an alysis of the product oils by H-1 NMR and by elemental analysis provided im portant information for the kinetic modeling. The kinetic model to characte rize changes in amount of hydrocarbon gas, light saturates, light aromatics , heavy saturates, heavy condensed aromatics, heavy non-condensed aromatics and coke was finally constructed. The apparent activation energy for crack ing of heavy saturates was found to be 76 kcal/mol, which is close to a val ue published on hexadecane cracking under high pressure in anhydrous condit ions. Application of the model to geological conditions shows that the crac king of heavy saturates occurs within a temperature range of 190 to 230 deg rees C, which is relatively a higher range than that usually accepted in pe troleum geochemistry. (C) 1999 Elsevier Science B.V. All rights reserved.