An analysis of kinetic data on TGA thermo-degradation of different types of unmatured kerogen

Abstract

Kinetic parameters are calculated from the thermogravimetric analytical data of different kinds of unmatured kerogen by using the Flynn curve-fitting techniques and the Zsako equation. The determination of the activation energy from the TGA plots involves only the reading of the temperature at a constant weight loss from several integral thermograms at different heating rates. From the slope of log β ( β = heating rate) vs 1/T, the approximate value of activation energy may be closely calculated. Accurate activation energy is obtained from the approximate value of E/ RT and constant b. The pre-exponential factor is calculated by the Zsako equation. Our research results have shown that there is no relation between kerogen types and the kinetic parameters of thermo-degradation in kerogen's oil-generating stage. However, the variation of kinetic parameters is related to the kerogen type. With the conversion degree increasing, the observed conversion trend is that the kinetic parameters of sapropel-type kerogen increase while those of humic-type kerogen decrease.