Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Metal – metal oxide or metal hydroxide
Reexamination Certificate
1999-07-01
2002-05-07
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Metal, metal oxide or metal hydroxide
C502S308000, C502S324000, C502S349000, C502S350000, C502S351000, C208S113000
Reexamination Certificate
active
06383975
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a procedure for the preparation of a new catalyst with application in hydrodenitrogenation and hydrodesulfurization of middle and heavy petroleum distillates. The catalyst object of the present invention is basically constituted by active metals and promoters, whose elements belong to groups VIII, VI, IVB of the periodic table, with specific properties for hydrodenitrogenation and hydrodesulfurization of middle and heavy petroleum oil fractions.
BACKGROUND OF THE INVENTION
It is a fact that an urgent need exists to improve the surrounding ecology, which has been deteriorated by the past generations common practices. It is not until now, the second half of the second millennium, that people are aware of the damage caused to life and living species. Industries tend to be modernized and to establish cleaner production systems. In the same way, the refining industry is focused in producing cleaner fuels with higher quality and with minimum contents of contaminants such as sulfur, nitrogen and heavy metals. However, as the ecological regulations become more strict each day, it is urgent to have processes as well as catalysts performing more efficiently and at the same time able to comply with the new requirements.
Without any doubt, hydrotreating processes are industrially considered the most efficient in contaminants removal and are used for mostly all crude fractions such as gasolines, diesel, vacuum distillates and residues. In order to achieve maximum hydrodesulfurization, hydrodenitrogenation and hydrodemetallization at the given process conditions, it is necessary using catalysts with high activity and selectivity to these reactions. A given process operating with a particular catalyst having such characteristics, will not only remove nitrogen, sulfur and metals, but will improve other fuel properties such as color, stability to gum formation, etc.
The present invention relates to a procedure to prepare a new catalyst that is highly active and selective for hydrodenitrogenating middle and heavy oil fractions, and additionally provides a high hydrodesulfurization and hydrodemetallization capacity. This invention also relates with the process conditions for its industrial application.
Catalyst activity and selectivity is determined and affected by such factors as the nature and properties of the catalyst support, the catalytic agents, activity and selectivity promoters, as well as the preparation and activation method used.
Current catalysts in hydrotreating processes, namely, hydrodesulfurization, hydrodenitrogenation and hydrodemetallization of oil fractions incorporate metals from groups VIII and VIB of the periodic table, and are usually supported on metallic oxides such as alumina, silica or silica alumina. Occasionally, secondary promoters or additives are used such as halogens, phosphorous, borum, etc., enhancing the catalytic properties mainly for a dispersing effect on the active phase or the modifications resulting in the support's physical and chemical properties.
Catalyst support properties play an important role in the catalytic activity. The first generation of catalyst supports had as their only function supporting or containing the active agents. During the 1970's, studies developed on properties and effects of catalytic supports revealed that these could be designed for specific uses.
The support is generally a porous solid constituted by metallic oxides such as gamma alumina, delta alumina, etc.; silica, silica-alumina, titania, titania alumina; among others. A catalyst support used for hydrotreating catalysts can have different geometric forms, such as spheres, pellets, cylindrical extrudates, trilobular and tetralobular forms, etc., and also different sizes going from nominal sizes of {fraction (1/30)} to ⅛ inch.
The method used to prepare catalysts also affects final catalyst activity and selectivity. Of the different methods used for preparing catalysts, (sol-gel, co-precipitation, etc.); the most efficient method known is support impregnation with a solution or solutions containing the active metals and/or promoters and/or additives. In this case, solutions must be very stable to prevent precipitation during impregnation stage and inside the matrix pores. It is necessary that the elements present in the solution be adsorbed and selectively distributed on both internal and external surface preventing its agglomeration.
U.S. patents relating to these procedures are the following:
U.S. Pat. No. 4,665,048 relates to a catalyst for hydrotreatment of oil and its fractions prepared by impregnation of ammonia solutions containing metals from groups VIII and VIB; and anions free derived from strong acids, followed by a drying and a calcination.
U.S. Pat. No. 4,769,129 relates to a method to hydrotreat hydrocarbon feeds using a catalyst containing vanadium sulfide prepared either in situ or outside the reaction zone. This method can be applied to gasolines, gas oils and residues for hydrotreatment, removing sulfur, nitrogen and metals.
U.S. Pat. No. 4,780,193 describes a process for hydrotreating catalytic cracking feeds at temperatures lower than 390° C. and pressures higher than 12,000 KPa, which improves cracking of feeds to produce high octane gasolines. Desulfurization taking place with this process, reduces SO
x
emissions on the catalytic cracking system, and also hydrodenitrogenation takes place as result of the high pressures used.
U.S. Pat. No. 4,886,594 relates to a catalyst formulation consisting on a hydrogenating agent, being a metal from group VIB of the periodic table and phosphorous component, laid on the surface of the support which is a refractory inorganic oxide, free from any zeolitic components. This catalyst is specially used for hydrodenitrogenation and hydrodemetallization of high sulfur content feeds.
U.S. Pat. No. 5,009,768 describes an invention relating to a hydrocatalytic process for vacuum gas oil hydrotreatment, residual feed or a combination of these, in the presence of 100 ppm V and Ni, at moderate partial pressures. The process consists in two or more stages using feed demetallization at levels lower than 10 ppm vanadium and nickel, and hydrodenitrogenation and hydroconversion by means of a combined catalyst bed. The hydrotreated product is then submitted to a catalytic cracking to obtain gasolines.
U.S. Pat. No. 5,246,569 discloses a process and a catalyst for hydrocarbons hydrodesulfurization. The catalyst is prepared by impregnation to achieve 0.3 to 3 weight percent of P
2
0
5
; 4.5 to 6 weight percent of CoO and 19 to 23 weight percent of MoO
5
and which is supported on alumina. Additionally, other organic or inorganic acids are incorporated to obtain more stable solutions.
The previous described technologies have been overwhelmed by the present invention; in catalyst properties, and its preparation procedure, as well as in catalyst performance, demonstrating a superior capacity for hydrotreating middle and heavy oil fractions.
SUMMARY OF THE INVENTION
The present invention is related to a catalyst with high catalytic activity and selectivity for hydrodenitrogenation, as well as a good hydrodesulfurization and hydrodemetallization activity on petroleum oil fractions, preferably middle and heavy fractions. This catalyst is obtained by impregnation of a solution containing metals from groups VIB and VIII of the periodic table. The support used is a porous refractory oxide whose metals belong to groups IIIA, IVA of the periodic table, or its combinations. Additionally, the support includes an additive in the form of an oxide whose metal belongs to group IVB of the periodic table. The impregnated material is thermally treated in an oxidizing atmosphere.
Once the catalyst is obtained, it is activated using presulfiding methods with sulfur compounds which easily decompose to generate the corresponding metallic sulfurs.
DETAILED DESCRIPTION OF THE INVENTION
The catalyst described in the present invention is able to hydrotreat middle and heavy oil fractions, u
de la Paz Teresa de Jesús Cortez
Oviedo Tomás Alberto Beltrán
Ramos René Zárate
Rivera Blanca Lucía Medellín
Rocha Ernesto Galvan
Bell Mark L.
Hailey Patricia L.
Instituto Mexicano del Petroleo
Roylance Abrams Berdo & Goodman L.L.P.
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