Colloidal Structures of Daqing and Gudao Vacuum Residua and Their Formation

ＣｏｌｏｉｄａｌＳｔｒｕｃｔｕｒｅｓｏｆＤａｑｉｎｇａｎｄＧｕｄａｏＶａｃｕｕｍＲｅｓｉｄｕａａｎｄＴｈｅｉｒＦｏｒｍａｔｉｏｎＬｉＳｈｅｎｇｈｕａ（ＬｏｇｉｓｔｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＣｏｌｅｇｅ，Ｃｈｏｎｇｑｉｎｇ６３００４２）ＬｉｕＣｈｅ...

Physical structures of Daqing vacuum residue with traceable n heptane insoluble and toluene soluble (HI TS) asphaltenes and Gudao vacuum residue with relatively much HI TS asphaltenes have been revealed with freeze fracture replication transmission electronic microscopy to assume colloidal configurations, in which the HI TS asphaltenes, in combination with some heavier and more polar resins, construct the mixed asphaltenes resins micelle, and the remaining lighter resins, aromatics and saturates act as the dispersing medium. It is indicated that the role of the n pentane insoluble and toluene soluble (PI TS) asphaltenes should be stressed in view of the colloidal character of vacuum residua. Analyses of the compositional and structural parameters of vacuum residua and their SARA fractions as well as their IR spectra suggest that both the high electronegativity heteroatoms and the molecular aromaticity contribute to the colloid formation of vacuum residua.