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

Although the oxidation of carbon monoxide on platinum is one of the oldest known catalytic reactions and one of the most thoroughly studied, it continues to pose difficulties and challenges to both the experimentalist and the theoretician. For the most part, these are due to the frequent observations of hysteresis, associated with steady-state multiplicity, and self-sustained oscillations in the reaction and to the fact that no generally accepted theoretical explanation for them is at hand. even though a large number of studies have addressed the subject.

Intrinsically Unstable Behavior during the Oxidation of Carbon Monoxide on Platinum

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

Influence of Catalyst Pore Size on Demetallation Rate

Influence of inerts on kinetic oscillations during the isothermal oxidation of hydrogen on platinum wires

Techniques for evaluating a heavy oil cracking catalyst

Measurements of the electrical power required to maintain a catalytic wire at a preset resistance (temperature) is a convenient method of determining the isothermal catalytic activity. When the wire is heated electrically abrupt changes in the temperature may occur. The purpose of this work is to study the influence of thermal shocks on the oxidation activity and resistance of palladium wires. Pretreatment steps involving abrupt cooling increased for several hours the catalytic activity of palladium wires toward the oxidation of hydrogen. This ''superactivity'' decayed slowly under reaction conditions and may disguise the intrinsic catalytic activity.

Kuppuswamy Rajagopalan

Papers

Influence of Catalyst Pore Size on Demetallation Rate

Influence of inerts on kinetic oscillations during the isothermal oxidation of hydrogen on platinum wires

Techniques for evaluating a heavy oil cracking catalyst

Influence of thermal shocks on the catalytic activity of palladium