Softening Point: An Indicator of Asphalt Granulation Behavior in the Selective Asphaltene Extraction (SELEX-Asp) Process

Granulation is an effectual method to deal with huge amounts of deoiled asphalt (DOA) produced in the residue selective asphaltene extraction (SELEX-Asp) process, and the softening point of DOA plays an important role in asphalt particle production. In this paper, the variation of the softening point under different operation conditions and its influence on asphalt granulation behavior were studied with various solvents and feedstocks. Moreover, properties and structures of five C7 asphaltenes were analyzed with 13C nuclear magnetic resonance (NMR) and X-ray diffraction (XRD) measurements to examine the reasons of asphalt softening point differences for various residues under the same operation conditions. Ordered degree index (OI) and softening point index (SI) were proposed to investigate the influence of asphalt ordered aromatic sheets on the softening point. High softening point asphalt could be obtained with lower temperatures and higher pressures of the extractor, a larger mass ratio of solvent to f...