A review of recent advances on process technologies for upgrading of heavy oils and residua

Deactivation of hydroprocessing catalysts

Catalyst deactivation due to coke formation is an important technological and economic problem in petroleum refining and in the petrochemical industry. Remedies to catalyst deactivation are sought by a variety of strategies involving modification of catalyst surface composition such as the use of polymetallic catalysts and/or by manipulation of the reaction environment which often limits the yield due to thermodynamic constrains (i.e., high hydrogen pressures, etc.). In the limit, when the activity reaches unacceptable limits, regeneration by burning off carbon residues can usually be attained, Regeneration can take place in situ, as in fixed-bed reactors, or in an adjacent reactor to which the catalysts is transported to, such as in moving-bed reactors or in fluidized-bed reactors. In the first case intermittent operation is required, whereas in the second case the operation is continuous, but a second regeneration reactor is required. The choice of the proper process cycle is an economic optimi...

Catalysts deactivation by coking

Catalyst deactivation in heavy petroleum and synthetic crude processing: a review

Publisher Summary This chapter discusses the elements of physical chemistry, heterogeneous catalysis, and reaction engineering that are necessary for a basic understanding of catalytic hydrodemetallation. It focuses on vanadium and nickel removal because these are the most abundant metals in petroleum. Following this, it discusses the nature of the metal compounds in petroleum oils and the targeted reactants. The chemical composition of the host petroleum and residuum is described, including a discussion of the two classes of metal compounds: (1) metalloporphyrins and (2) nonporphyrin metals. A comparison between the characteristics of vanadium and nickel complexes and their distribution in residua is also presented. Commercial residuum hydroprocessing technology is then discussed to establish the role and requirements of hydroprocessing in the overall refinery residuum conversion scheme. Finally, the kinetics and mechanisms of catalytic HDM reactions are presented and future perspectives for the study of residuum hydroprocessing and the rational design of hydrodemetallation catalysts and processes are highlighted.

Dan Luss

Papers

Influence of Catalyst Pore Size on Demetallation Rate

Regeneration of Adiabatic Fixed Beds