Catalyst – solid sorbent – or support therefor: product or process – Regenerating or rehabilitating catalyst or sorbent – Gas or vapor treating
Reexamination Certificate
2000-07-03
2003-10-21
Silverman, Stanley S. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Regenerating or rehabilitating catalyst or sorbent
Gas or vapor treating
Reexamination Certificate
active
06635596
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a process for regenerating additive-based catalysts.
2. Prior art
Additive-containing hydrotreating catalysts are known in the art. For example, European patent application 0 601 722 describes hydrotreating catalysts comprising a gamma-alumina support impregnated with a Group VIB metal component, a Group VIII metal component, and an organic additive which is at least one compound selected from the group of compounds comprising at least two hydroxyl groups and 2-10 carbon atoms, and the (poly)ethers of these compounds.
WO 96/41848 describes a process for preparing an additive-containing catalyst in which the additive mentioned above is incorporated into a finished catalyst composition. That is, a catalyst composition comprising hydrogenation metal components in the oxidic form, brought into that form by calcination, is contacted with the specified additive.
Japanese patent application 04-166231 describes a hydrotreating catalyst prepared by a process in which a support is impregnated with an impregnation solution comprising a Group VIB metal component, a Group VIII metal component, and, optionally, a phosphorus component. The support is dried at a temperature below 200° C., contacted with a polyol, and then dried again at a temperature below 200° C. Japanese patent application 04-166233 describes an alkoxycarboxylic acid-containing catalyst prepared by substantially the same process.
Japanese patent application 06-339635 describes a hydrotreating catalyst prepared by a process in which a support is impregnated with an impregnation solution comprising an organic acid, Group VIB and Group VIII hydrogenation metal components, and preferably a phosphorus component. The impregnated support is dried at a temperature below 200° C. The dried impregnated support is contacted with an organic acid or polyol, after which the thus treated support is dried at a temperature below 200° C.
Japanese patent application 06-210182 describes an additive-containing catalyst based on a boria-alumina support comprising 3-15 wt. % of boria. Non-prepublished European patent application No. 00201039 in the name of Akzo Nobel filed on Mar. 23, 2000, describes a catalyst containing an organic compound comprising N and carbonyl.
The additive-containing catalysts of the above references all show an increased activity in the hydrotreating of hydrocarbon feeds as compared to comparable catalysts which do not contain an additive.
During the hydrotreating of hydrocarbon feeds, the activity of the catalyst decreases. This is caused, int. al., by the accumulation on the catalyst surface of carbon-containing deposits, which are generally referred to as coke. The accumulation of these deposits is detrimental to the activity of the catalyst. Therefore, a catalyst .is commonly regenerated after a certain period of use by burning off the coke, which renders the catalyst suitable for reuse.
In the case of additive-containing catalysts, however, it has appeared that specific regeneration conditions, in particular a lower regeneration temperature, are essential to obtain an acceptable activity for the regenerated catalyst.
Additionally, and surprisingly, it has been found that by proper selection of the regeneration conditions it is in fact possible to regenerate an additive-based catalyst in such a way that a catalyst is obtained which still shows an increased activity as compared to a comparable catalyst which never contained an additive. This is in contradiction to the earlier assumption that the effect of the additive would be lost upon. regeneration of the catalyst. In WO 96/41848 this is stated as follows. “Although these catalysts do indeed show improved hydrotreating activity as compared with conventional hydrotreating catalysts which do not contain an additive, this improved activity will only appear when the catalyst is used for the first time. Regeneration of the catalyst by burning off coke results in removal of the additive from the catalyst, so that the improvement in activity is lost in the further catalyst life cycles.”
SUMMARY OF THE INVENTION
The present invention therefore pertains to a process for regenerating a used additive-based catalyst comprising the step of contacting. the additive-based catalyst with an oxygen-containing gas, the regeneration process being carried out under such conditions that the maximum catalyst temperature during the regeneration process is at most 500° C.
In a second embodiment the present invention pertains to a regenerated additive-based hydrotreating catalyst obtained by the above process.
In a third embodiment the present invention pertains to a process for the hydrotreating of hydrocarbon feeds in which a feed is contacted at elevated temperature and pressure with the above catalyst.
Other embodiments of the present invention are based on details including catalyst stripping and regeneration conditions and process details, all of which are hereinafter disclosed in the following discussion of each of these facets of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The Used Additive-based Catalyst
In the context of the present specification, the term additive-based catalyst is intended to refer to a catalyst which contained an organic additive before use, even though during use or, optionally, depending on the presulphiding conditions, during presulphiding, said additive was lost from the catalyst.
The used additive-based catalyst which is to be regenerated in accordance with the present invention may have been used in any hydrotreating process. In the context of the present specification, hydrotreating is intended to refer to all processes in which one or more of hydrodesulfurisation, hydrodenitrogenation, and hydrodearomatisation, optionally accompanied by some conversion into products with a lower boiling range, takes place. Use in (deep) hydrodesulfurisation, hydrodenitrogenation, or hydrodearomatisation is most common for additive-based catalysts. Examples of suitable feeds include straight run gas oil, light catalytically cracked gas oil, and light thermally cracked gas oil, middle distillates, kero, naphtha, vacuum gas oils, heavy gas oils, and residues.
The reaction temperature generally is 200-500° C., preferably 280-430° C. The reactor inlet hydrogen partial pressure generally is 5-200 bar, preferably 10-150 bar. The liquid hourly space velocity preferably is between 0.1 and 10 vol./vol.h, more preferably between 0.5 and 4 vol./vol.h. The H
2
/oil ratio generally is in the range of 50-2000 NI/I, preferably in the range of 80-1500 NI/I.
In principle, the used additive-based catalyst may be any used hydrotreating catalyst which comprises a Group VIB hydrogenation metal, a Group VIII hydrogenation metal, and generally a carrier, and which contained an organic additive before it was used or, as the case may be, presulfided.
As Group VIB metals may be mentioned molybdenum, tungsten, and chromium. Group VIII metals include nickel, cobalt, and iron. Catalysts comprising molybdenum as Group VIB metal component and nickel and/or cobalt as Group VIII metal component are the most common. The catalyst usually has a metal content in the range of 0.1 to 50 wt. %, calculated on the dry weight of the catalyst not containing the additive. The Group VIB metal will frequently be present in an amount of 5-35 wt. %, preferably 15-30 wt. %, calculated as trioxide. The Group VIII metal will frequently be present in an amount of 1-10 wt. %, preferably 2-7 wt. %, calculated as monoxide. The catalyst may also contain other components, such as phosphorus, halogens, and boron. Particularly, the presence of phosphorus in an amount of 1-10 wt. %, calculated as P
2
O
5
, may be preferred.
The catalyst carrier may comprise the conventional oxides, e.g., alumina, silica, silica-alumina, alumina with silica-alumina dispersed therein, silica-coated alumina, magnesia, zirconia, boria, and titania, as well as mixtures of these oxides. As a rule, preference is given to the carrier comprising alumina, silica-a
Eijsbouts Sonja
Houtert Franciscus Wilhelmus
Jansen Marcel Adriaan
Kamo Tetsuro
Plantenga Frans Lodewijk
Akzo Nobel N.V.
Johnson Edward M.
Morris Louis A.
Silverman Stanley S.
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