Transformation of the Resins of High-Sulfur Tar in the Cracking Process
摘要
The article presents the results of studying resins isolated from the liquid cracking products of sulfur tar from the Omsk Oil Refinery. Thermal treatment was carried out at 500°C for 15, 30, 45, and 60 min. It was found that the yield of coke increased with the duration of tar cracking due to the condensation of resins into asphaltenes and then into coke. Changes in the structural-group parameters of resins in the course of cracking process were established using 1H NMR spectroscopic data, elemental composition, and the results of molecular weight measurements. Averaged resin molecules became more condensed, and they were characterized by an increased concentration of aromatic fragments and a decrease in the numbers of naphthenic fragments and aliphatic substituents. The set of data on changes in the composition of cracking products together with an analysis of sulfur distribution in the products indicated a significant contribution of sulfur-containing structural fragments of resins to the accumulation processes of thiophene derivatives. It was shown that the cracking of resins was accompanied by the formation of a wide range of low-molecular-weight sulfur-containing compounds in the composition of oils.