Thermal Behavior of Heavy Oil Catalytic Pyrolysis and Aquathermolysis

Abstract

There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA (S: saturates, A: aromatics, R: resins, A: asphaltenes) analysis has shown a significant increase in light hydrocarbon content during aquathermolysis. Moreover, the elemental analysis has indicated an increase in C and H content by almost 4% and 6%, respectively, with a significant decrease in S and O content by up to 23% in the presence of iron tallates. These results have been further confirmed by infrared spectrometry. The obtained IR data indicated that asphaltene and resin compounds transform into light hydrocarbons after aquathermolysis. On another hand, the activation energy of heavy oil pyrolysis decreased in the presence of the utilized catalyst; meanwhile, the reaction rate increased, especially in the temperature range of 200–480 °C, which may validate a significant effect of the used catalyst in real conditions. Moreover, the obtained thermodynamic data showed a decrease in the enthalpy and entropy of activation of oil pyrolysis in the presence of iron tallates. Our results are encouraging in terms of energy consumption, optimization, and process control and should be validated by a larger sample size.