Calculation of the Rate Constants of Thermal Cracking and Condensation Reactions of High-Sulfur Tar Asphaltenes

Abstract: The paper presents the results of a comparative analysis of the cracking products of three samples of high-sulfur tars obtained at a temperature of 500°C and different process durations. The reaction rate constants of the thermal transformations of asphaltenes in the test tars were calculated using a kinetic model of the cracking process. It was found that the rate of asphaltene condensation into coke depends not only on the initial concentration of asphaltenes but also on their molecular structure. It was shown that the cracking of saturated fragments of the structural blocks of asphaltene molecules containing large aliphatic substituents led to the accumulation of secondary asphaltenes with a high degree of aromaticity, which had higher reaction rates of condensation into coke.