Assessment of structural changes in resins and asphaltenes depending on the duration of cracking using structural group analysis

Changes in structural parameters of secondary resins and asphaltenes formed upon the cracking of asphaltenes, resins and their mixture were assessed at different process durations. Resins and asphaltenes isolated from heavy methane crude of Zyuzeevskoye oil field (Tatarstan) and their mixture (Resins + Asphaltenes) were cracked in a closed reactor at 450°C for 60, 90 and 120 minutes. With increasing the duration of resins and asphaltene cracking, condensation reactions leading to an increase in the yield of coke and the formation of low-molecular-weight, highly aromatic secondary resin and asphaltene molecules accelerated. It was found that the directions of thermal transformations of resin and asphaltene molecules are similar. The joint presence of resins and asphaltenes in a mixture changed the direction on their thermal transformations in the course of cracking, which was reflected in the quantitative data on the mass balance and structural parameters of secondary resins and asphaltenes formed upon the cracking of a mixture of resins with asphaltenes. Differences in the structural characteristics of resins and asphaltenes formed upon the cracking of single-component samples and their mixtures were revealed.