Hydrodemetallization

HDM Hydrodemetallization (yields metal sulfides) Ni-MoS2/Al203... 

The most important undesired metallic impurities are nickel and vanadium, present in porphyrinic structures that originate from plants and are predominantly found in the heavy residues. In addition, iron may be present due to corrosion in storage tanks. These metals deposit on catalysts and give rise to enhanced carbon deposition (nickel in particular). Vanadium has a deleterious effect on the lattice structure of zeolites used in fluid catalytic cracking. A host of other elements may also be present. Hydrodemetallization is strictly speaking not a catalytic process, because the metallic elements remain in the form of sulfides on the catalyst. Decomposition of the porphyrinic structures is a relatively rapid reaction and as a result it occurs mainly in the front end of the catalyst bed, and at the outside of the catalyst particles. 

Ying, Z.-S. Gevert, B. Otterstedt, J.-E., and Sterte, J., Hydrodemetalation of residual oil with catalysts using fibrillar alumina as carrier material. Applied Catalysis, A General, 1997. 153(1-2) pp. 69-82. 

Ancheyta-Iuarez, J. Maity, S. K. Betancourt-Rivera, G., et al., Comparison of different Ni-Mo/alumina catalysts on hydrodemetallization of Maya crude oil. Applied Catalysis, A General, 2001. 216(1-2) pp. 195-208. 

Trickle-bed reactors are used in catalytic hydrotreating (reaction with H2) of petroleum fractions to remove sulfur (hydrodesulfurization), nitrogen (hydrodenitrogena-tion), and metals (hydrodemetallization), as well as in catalytic hydrocracking of petroleum fractions, and other catalytic hydrogenation and oxidation processes. An example of the first is the reaction in which a sulfur compound is represented by diben-zothiophene (Ring and Missen, 1989), and a molybdate catalyst, based, for example, on cobalt molybdate, is used ... 

Richard J. Quann, Robert A. Ware, Chi-Wen Hung, and James Wei, Catalytic Hydrodemetallation of Petroleum... 

Wei, J. 1987. Towards the design of hydrodemetallation catalysts. In Catalyst Design Progress and Perspectives, L. L. Hegedus, ed.. New York Wiley. 

In Section III, commercial residuum hydroprocessing technology is discussed to establish the role and requirements of hydroprocessing in the overall refinery residuum conversion scheme. Commercial residuum hydroprocessing catalysts and residuum hydrodesulfurization (RDS)-hydrodemetallation (HDM) technology are reviewed briefly. 

In the last section, future perspectives for the study of residuum hydroprocessing and the rational design of hydrodemetallation catalysts and processes are offered. 

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