Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics

Abstract

The Democratic Republic of the Congo holds important reserves of oil shale which is still under geological status. Herein, the characterization and pyrolysis kinetics of type I kerogen-rich oil shale of the western Central Kongo (CK) were investigated. X-ray diffraction, Fourier-transform infrared spectroscopy and thermal analysis (TG/DTA) showed that CK oil shale exhibits a siliceous mineral matrix with a consistent organic matter rich in aliphatic chains. The pyrolysis behavior of kerogen revealed the presence of a single mass loss between 300 and 550 °C, estimated at 12.5% and attributed to the oil production stage. Non-isothermal kinetics was performed by determining the activation energy using the iterative isoconversional model-free methods and exhibits a constant value with E = 211.5 ± 4.7 kJ mol −1. The most probable kinetic model describing the kerogen pyrolysis mechanism was obtained using the Coats-Redfern and Arrhenius plot methods. The results showed a unique kinetic triplet confirming the nature of kerogen, predominantly type I and reinforcing the previously reported geochemical characteristics of the CK oil shale. Besides, the calculation of thermodynamic parameters (ΔH*, ΔS* and ΔG*) corresponding to the pyrolysis of type I kerogen revealed that the process is non-spontaneous, in agreement with DTA experiments.

Catalytic pyrolysis of coconut oil with Ni/SBA-15 for the production of bio jet fuel

“…This behavior has been frequently observed in several works reported in the literature, such as Wako and collaborators 65 in their research on the kinetic study of the thermal degradation of rubber seed oil. According to Bouamoud and collaborators, 66 this shift is due to the temperature gradient during the reaction process, which is smaller at low heating rates and larger at a high heating rates, that is, the increase in the heating rate causes a delay in material degradation. 67 However, this behavior was not observed in the OC1NS sample, since there was a decrease in the maximum temperatures between the heating rates of 15 and 20 °C min −1 .…”

A review on thermogravimetric analysis‐based analyses of the pyrolysis kinetics of oil shale and coal

“…The activation energy obtained by these five methods had a good fitting effect, and the author put forward the early first‐order reaction mechanism function and the late second‐order reaction mechanism function by the least‐squares method to account for the pyrolysis process of organic matter in oil shale. Bouamoud et al 99 employed the FWO and KAS iteration methods to study the activation energy parameters of type I oil shale rich in fatty chains in the Congo area. The accuracy of activation energy can be effectively improved by iterative processing.…”

Thermogravimetric Pyrolysis Behavior and Kinetic Study of Two Different Organic-Rich Mudstones via Multiple Kinetic Methods

“…Thermogravimetric analysis (TGA) is an efficient technique to study pyrolysis kinetics and behavior with thermogravimetric curves [13] and is extensively used in pyrolysis research of organic-rich rocks, such as oil shale [14][15][16] and coal [17][18][19]. However, the pyrolysis kinetic research of other organic-rich rocks is seldom reported, and more theoretical research via thermogravimetric analysis is necessary for development and application.…”