Revisiting Asphaltene Precipitation from Crude Oils: A Case of Neglected Kinetic Effects
H. Scott Folger, Ph.D.
University of Michigan
Abstract:
Asphaltenes represent the largest and most polar fraction of crude oil and have been labeled the “cholesterol of the petroleum industry” due to the multitude of problems they cause, costing tens of millions of dollars each year. Heavy oils and tar sands are likely to be a significant source of energy and petrochemicals in the near future and have a high asphaltene content highlighting the importance of understanding this complex petroleum fraction. Research conducted at the University of Michigan focuses on understanding the fundamental surface science, colloid chemistry, thermodynamics and kinetic behavior of asphaltenes. For several decades, it was assumed that the solubility of asphaltenes could be determined using short time-length experiments, and predictive thermodynamic models relied on this assumption. However, using SANS, SAXS, optical microscopy, and centrifugation-based separation, we demonstrated that the time required to precipitate asphaltenes could vary from a few minutes to several months and invalidated many thermodynamic models of asphaltene stability. This finding that there is no critical precipitation onset has opened up a new paradigm for understanding asphaltene precipitation. The cause of slow precipitation kinetics has been shown by population balance modeling to be a reaction-limited aggregation growth process.
Biosketch:
H. Scott Fogler is the Ame and Catherine Vennema professor of chemical engineering and the Arthur F. Thurnau professor at the University of Michigan in Ann Arbor and was the 2009 President of the American Institute of Chemical Engineers. He received his B.S. from the University of Illinois and his M.S. and Ph.D. from the University of Colorado. He is also the author of the Elements of Chemical Reaction Engineering, which is the dominant book in this area worldwide, and co-author with Steven LeBlanc of the book Strategies for Creative Problem Solving. Scott and his students are well known for their work on the application of chemical reaction engineering principles to the petroleum industry They have published over 200 research articles, in an areas such as acidization of petroleum wells, gellation kinetics wax deposition in subsea pipelines and asphaltene flocculation and deposition kinetics. In 1996 he was recipient of the Warren K. Lewis award from the American Institute of Chemical Engineers for contributions to chemical engineering education. He is the recipient of 11 named lectureships.