Catalytic role of various clay minerals during the thermal reaction process with oxidized and pyrolyzed oils

This study evaluated this thermal reaction behavior of oxidized and pyrolyzed oils containing diverse clay minerals by means of differential scanning calorimetry (DSC) technology. The catalytic role of various clay minerals for thermal reaction processes involving oxidized oil and pyrolyzed oil during in situ combustion (ISC) was investigated in conjunction with kinetic calculation methods as well. The results demonstrated that all four clay minerals could shorten its temperature region of oxidized oil low-temperature oxidation (LTO) stage, with the peak temperature during the LTO stage of oxidized oil containing montmorillonite being dramatically reduced. The catalytic role of montmorillonite and illite on oxidized oil is more powerful in the high-temperature oxidation (HTO) stage with higher peak heat flow. The Lewis acid sites within clay minerals affect free radical reactions within the crude oil pyrolysis process, and in situ reforming performance of 400°C pyrolyzed oils containing clay minerals is less effective, along with low heat release in the LTO stage. Clay minerals can considerably minimize the activation energy during thermal reaction of oxidized oil, contributing to the coke generation and conversion in the fuel deposition (FD) stage and boosting the success rate of the ISC procedure. The catalytic role of clay minerals in the oxidation and pyrolysis reactions of crude oil contributes to the prediction of fuel deposition and the expansion of the combustion front during ISC under diverse types of rock conditions.