Kinetic study of thermal and catalytic pyrolysis of Brazilian heavy crude oil over mesoporous Al-MCM-41 materials

This study aimed to evaluate the activity of Al-MCM-41, as mesoporous heterogeneous catalyst, for the thermal and catalytic degradation of a Brazilian heavy crude oil (14A degrees API), via thermogravimetry. The American Petroleum Institute gravity (A degrees API) is a measure of how light of heavy petroleum is when compared to water. The API value is an inverse measure of the relative density of a petroleum liquid, and it is used to compare the relative densities of petroleum samples. The catalytic activity was investigated as a function of different concentration of Al-MCM-41 (1, 3, 5, 10 and 20 mass%) added to the oil, as well as the apparent activation energy relative to degradation process. The TG runs were carried out at temperature range of 30-900 A degrees C, at heating rates of 5, 10 and 20 A degrees C min(-1), under nitrogen atmosphere. From TG/DTG tests, the material presented effective catalytic activity when added to the heavy oil at concentration higher than 5 mass%. This property was clearly evidenced by the activation energy values. By the application of Ozawa-Flynn-Wall kinetic model, it was observed that when the amount of catalyst was increased, the value of the apparent activation energy decreased from 103 kJ mol(-1) (without catalyst) to 70 kJ mol(-1) (with 20 mass% of catalyst).