932
Energy & Fuels 1996, 10, 932-940
Experimental Determination of the Rate Constants of the n-C25 Thermal Cracking at 120, 400, and 800 bar: Implications for High-Pressure/High-Temperature Prospects F. Behar* and M. Vandenbroucke Geochemistry Department, IFP, 1-4 Avenue de Bois Pre´ au, 92506 Rueil-Malmaison Cedex, France Received March 6, 1996. Revised Manuscript Received April 26, 1996X
The aim of this work is to determine the apparent rate constants for the n-C25 thermal cracking and, then, to study pressure effect on these rate constants so as to evaluate n-alkane stability in high-pressure/high-temperature deep prospects. Pyrolyses were carried out in anhydrous closed system (gold vessels) during times ranging from 1 to 360 h under isothermal conditions (325425 °C) and various pressures (120, 400, and 800 bar) in the range of those occurring in petroleum systems. Results show that degradation of n-C25 follows a first-order kinetics under isothermal conditions at 120 bar. The main chemical class produced along increasing severity is the saturated hydrocarbons ranging from C10 to C22 (80 wt %). The gas contribution is very low (
