Comparison of Isothermal and Nonisothermal Pyrolysis Data with Various Rate Mechanisms: Implications for Kerogen Structure

摘要

In order to derive chemical kinetic rate constants that can be extrapolated over a wide range of reaction conditions, it is usually necessary to fit the kinetic data to a model that accounts for important aspects of the reaction mechanism. Kerogen pyrolysis is an extremely complicated process, so it is impossible to consider individual reactions. Therefore, the goal is to construct a global reaction model in which important stages of reaction and classes of reactions are treated by a single rate expression. Two global reaction models that have been used frequently for kerogen pyrolysis are the multiple-parallel reaction model (1-3) and the kerogen-to-bitumen-to-oil serial reaction model (4-5). While these models may be able to describe some aspects of kerogen pyrolysis, they give fundamentally different predictions for certain aspects of oil generation. The purpose of this paper is to examine kerogen pyrolysis under conditions where the differences between these models can be tested. We find that both models have significant weaknesses. We discuss the implications of our results for the structure of kerogens, and we attempt to derive more realistic global models that take these possible structures into account. One promising model is the alternate pathway model (6). 22 refs., 5 figs., 2 tabs. (ERA citation 14:017036)