Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Metal – metal oxide or metal hydroxide
Reexamination Certificate
2000-01-13
2003-10-21
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Metal, metal oxide or metal hydroxide
C502S221000, C502S220000, C502S219000, C502S222000, C502S223000, C502S315000, C502S313000, C502S316000
Reexamination Certificate
active
06635599
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a process for the preparation of a hydroprocessing catalyst, to the catalyst composition obtainable by said process, and to the use of said catalyst composition in hydroprocessing applications.
BACKGROUND OF THE INVENTION
In the hydroprocessing of hydrocarbon feedstocks, the feedstocks are hydrotreated and/or hydrocracked in the presence of hydrogen. Hydroprocessing encompasses all processes in which a hydrocarbon feed is reacted with hydrogen at elevated temperature and elevated pressure, including processes such as hydrogenation, hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, hydrodearomatization, hydroisomerization, hydrodewaxing, hydrocracking, and hydrocracking under mild pressure conditions, which is commonly referred to as mild hydrocracking.
In general, hydroprocessing catalysts are composed of a carrier with a Group VIB metal component and a Group VIII non-noble metal component deposited thereon.
Generally, such catalysts are prepared by impregnating a carrier with aqueous solutions of compounds of the metals in question, followed by one or more drying and calcination steps. Such a catalyst preparation process is described, e.g., in U.S. Pat. No. 2,873,257 and EP 0 469 675.
Another possibility is to coprecipitate the carrier material with one Group VIB. and one Group VIII non-noble metal component as, e.g., disclosed in U.S. Pat. No. 3,280,040. As the carrier itself has no or little catalytic activity, the activity of the above carrier-containing catalysts in hydroprocessing is rather moderate. It is therefore an object of the present invention to provide a catalyst, which can be applied without a carrier. Such carrier-free catalysts are generally referred to as bulk catalysts.
The preparation of bulk catalysts is known from, e.g., EP 0 379 433, where one Group VIII non-noble metal component and one Group VIB metal component are co-precipitated.
It is noted that all the above catalysts comprise one Group VIII non-noble metal and one Group VIB metal. Such catalysts have only moderate activity in hydroprocessing. It is therefore an object of the present invention to provide catalysts with increased catalytic activity.
A more recent development is the application of catalysts comprising one Group VIII non-noble metal and two Group VIB metals.
Such a catalyst is disclosed in, e.g., JP 09000929, U.S. Pat. No. 4,596,785, U.S. Pat. No. 4,820,677, and U.S. Pat. No. 3,678,124.
The catalyst of JP 09000929, which is a carrier-containing catalyst, is prepared by impregnating an inorganic support with cobalt or nickel as Group VIII non-noble metal and molybdenum and tungsten as Group VIB metals.
The catalyst of U.S. Pat. No. 4,596,785 comprises the disulfides of at least one Group VIII non-noble metal and at least one Group VIB metal. The catalyst of U.S. Pat. No. 4,820,677 is an amorphous sulfide comprising iron as Group VIII non-noble metal and a metal selected from molybdenum, tungsten or mixtures thereof as Group VIB metal, as well as a polydentate ligand such as ethylene diamine. In both references the catalyst is prepared via co-precipitation of water-soluble sources of one Group VIII non-noble metal and two Group VIB metals in the presence of sulfides. The sulfidic precipitate is isolated, dried, and calcined. All process steps have to be performed in an inert atmosphere, which means that sophisticated techniques are required to carry out this process, in order not to convert the metal sulfides into their oxides. It is therefore a further object of the present invention to provide a process which is technically simple and robust and which does not require any handling under an inert atmosphere during the preparation of the catalyst.
U.S. Pat. No. 3,678,124 discloses oxidic bulk catalysts to be used in oxidative dehydrogenation of paraffin hydrocarbons. The catalysts are prepared by co-precipitating water-soluble components of the corresponding metals.
SUMMARY OF THE INVENTION
It has surprisingly been found that the above objectives can be met by a catalyst preparation process which, in one embodiment, comprises the steps of combining and reacting at least one Group VIII non-noble metal component in solution and at least two Group VIB metal components in solution in a reaction mixture to obtain an oxygen-stable precipitate and subjecting the precipitate to a sulfidation step.
In another embodiment, the present invention comprises a catalyst composition obtained by the above process.
In a further embodiment, the present invention comprises a process for hydroprocessing a hydrocarbon feedstock that uses the above catalyst composition.
Other embodiments of the present invention encompass further details relating to the catalyst preparation process, further ingredients in the catalyst composition and further details concerning the process for use of the catalyst, all of which are hereinafter disclosed in the following discussion of each of those facets of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Catalyst Preparation Process
The present invention pertains to a process for preparing a catalyst composition comprising sulfidic bulk catalyst particles comprising at least one Group VIII non-noble metal and at least two Group VIB metals which comprises the following process steps (i) combination and reaction of at least one Group VIII non-noble metal component in solution and at least two Group VIB metal components in solution in a reaction mixture to obtain an oxygen-stable precipitate, and (ii) sulfidation of the precipitate.
Process Step (i)
It is essential to the process of the present invention that the metal components are completely dissolved when they are combined and/or reacted to form a precipitate. It is possible, e.g., to combine the metal components when they are already in the dissolved state and then have them react to form a precipitate. However, it is also possible to combine one or more of the metal components, which are partly, or entirely in the solid state with further metal components. However, in this case, care must be taken that the metal components, which are partly or entirely in the solid state will dissolve when present in the reaction mixture. In other words, at least once during process step (i), all metal components must be present wholly as a solution. In cases where metal components are combined partly or entirely in the solid state, the metals are actively dissolved in the reaction mixture, for instance by stirring, increasing the amount of solvent, changing the solvent, changing the temperature, or changing the pH or adding a complexing agent which leads to the formation of a soluble complex of the metal.
As stated above, the reaction mixture is reacted to obtain an oxygen-stable precipitate. Precipitation can be effected by, e.g.,
(a) changing the pH during or after combination of the metal component solutions to such a value that precipitation is induced;
(b) adding a complexing agent during or after combination of the metal component solutions, which complexing agent complexes one or more of the metals to prevent. precipitation of the metals, and thereafter changing the reaction conditions, such as temperature or pH, such that the complexing agent releases the metals for precipitation;
(c) adjusting the temperature during or after combination of the metal component solutions to such a value that precipitation is induced;
(d) lowering the amount of solvent during or after combination of the metal component solutions such that precipitation is induced;
(e) adding a non-solvent during or after combination of the metal component solutions to induce precipitation thereof, with a non-solvent meaning that the precipitate is essentially not, soluble in this solvent; or
(f) adding an excess of either of the components to such an extent that precipitation is induced.
Adjusting the pH in, e.g., options (a) or (b) can be done by adding a base or an acid to the reaction mixture. However, it is also possible to add compounds which upon the temperature increasing will decompose into
Cerfontain Marinus Bruce
Eijsbouts Sonja
Homan Free Hermannus Willem
Miseo Sabato
Oogjen Bob Gerardus
Bell Mark L.
Exxonmobil Research & Engineering Company
Hailey Patricia L.
Morris Louis A.
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