Asphaltenes: Chemical Transformation During Hydroprocessing of Heavy Oils

During the upgrading of heavy petroleum, asphaltene is the most problematic impurity since it is the main cause of catalyst deactivation and sediments formation. Exploring many aspects related to asphaltenes composition and conversion, Asphaltenes: Chemical Transformation during Hydroprocessing of Heavy Oils highlights the various changes that these heavy and complex molecules undergo during catalytic hydroprocessing.

After defining and characterizing asphaltene structure, the book examines the composition of petroleum and the processes and catalysts for upgrading heavy oils. It then details the characterization of asphaltenes after hydroprocessing and the effect of reaction conditions on their structures. The authors also analyze the deactivation and characterization of spent hydroprocessing catalysts as well as the role played by asphaltenes. They cover sediments formation during hydroprocessing and the role of asphaltenes on it. The final chapters describe the hydrocracking and kinetics of asphaltenes and the fractionation of heavy crudes and asphaltenes.

Due to the increasing production of heavy crude oils, asphaltene has become one of the most studied molecules. This book provides a deep understanding of how asphaltenes transform during hydroprocessing, offering insight on designing catalysts and processing for the upgrading of heavy oils.

Jorge Ancheyta is an R&D Project Leader in the Mexican Institute of Petroleum and a professor in the School of Chemical Engineering and Extractive Industries at the National Polytechnic Institute in Mexico City, Mexico.
Fernando Trejo is a researcher in the Center of Research in Applied Science and Advanced Technology at the National Polytechnic Institute in Mexico City, Mexico.
Mohan Singh Rana works at the Kuwait Institute for Scientific Research in Ahmadi, Kuwait.

Definition and Structure of Asphaltenes
Introduction
Variables Affecting the Asphaltenes Precipitation
Reversibility of Asphaltenes Precipitation
Elemental Composition of Asphaltenes
Asphaltenes Density
Characterization of Asphaltenes
Role of Resins in Stabilizing Asphaltenes

Hydroprocessing of Heavy Oils
Introduction
Composition of Heavy Petroleum Feeds
Upgrading of Heavy Oils
Components of Hydroprocessing Catalyst
Effect of Catalyst Properties on Hydroprocessing Activities
Catalyst Life (Catalyst Stability)

Changes in Asphaltenes during Hydrotreating
Introduction
Asphaltenes Characterization after Hydrotreating
Influence of Reaction Conditions on Asphaltene Structure

Catalyst Deactivation due to Asphaltenes
Introduction
Origin of Coke, Mechanism of Its Formation, and Properties
The Role of the Asphaltenes in Coke Formation
Catalyst Deactivation in Fixed-Bed Reactors
Influence of Coke and Metals Deposition on Catalyst Deactivation during Hydroprocessing
Characterization of Spent Catalysts
Effect of Reaction Conditions on Catalyst Deactivation
Catalyst Formulation and Its Effect on Asphaltenes Conversion
Alternatives Approaches for Preventing Coke Deposition
Regeneration and Rejuvenation of Spent Catalyst

Sediments Formation
Introduction
Sediments Analysis or Sediment Tests
Possible Reaction Mechanism and Compatibilities between the Components
Role of Catalyst and Feed on Sediments Formation
Effect of Hydroprocessing Reaction Conditions on Sediment Formation
Presumptions and Remedies for Sediment Formation

Hydrocracking and Kinetics of Asphaltenes
Introduction
Effect of Reaction Conditions on Asphaltene Hydrocracking
Reaction Pathways of Asphaltene Hydrocracking
Kinetic Modeling of Asphaltenes Hydrocracking

Fractionation of Heavy Crudes and Asphaltenes
Introduction
Distillation and Separation of Crude Oil Fractionation of Asphaltenes by Different Techniques
Structure and Composition of Crude and Asphaltenes after
Fractionation
Concluding Remarks and References appear at the end of each chapter.