CORRELATIONS BETWEEN PROPERTIES OF VARIOUS FEEDSTOCKS AND PRODUCTS OFVISBREAKING

Quantitative description of the correlations between some characterist ics (density, viscosity, asphaltene and sulfur contents, stability) of the vacuum residues and products of their visbreaking, and of the cha nges in the feed properties as a result of visbreaking in a real comme rcial visbreaker was done. The asphaltenes contents is higher in the p etroleum products having higher density and viscosity. The higher the feed viscosity, the higher the visbreakate viscosity, but also the hig her the relative decrease in the viscosity. There is no correlation be tween stability and the asphaltenes contents both for the feed and for the visbreakate. The higher the asphaltenes contents in the feed, the lower the relative increase in the asphaltenes contents during visbre aking. It indicates prevailing reactions of condensation of the asphal tenes precursors (resins, etc.) for the light stocks. For heavier stoc ks, cracking of the asphaltenes plays more significant role; starting from the asphaltene content in the feed of 7-9%, reactions of the cond ensation and cracking are approximately of the same rate, and increase in asphaltene content takes place mainly due to concentrating them in the visbreaking residue as a result of distillation of the visbroken product. Two groups of feedstocks may be defined from the point of vie w of their behavior in visbreaking: low-sulfurized (S<1%) and high-sul furized ones (S>2%). In the feedstocks with low sulfur contents, the a sphaltenes contents increases sharply, whereas for the high-sulfurized stocks the relative increase in the asphaltenes contents is low.