Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-04-10
2002-12-10
Wood, Elizabeth D. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S216000, C502S217000, C502S219000, C502S220000, C502S221000, C502S222000, C502S223000
Reexamination Certificate
active
06492296
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for sulfiding a catalyst containing an S (sulfur)-containing organic additive, in particular a hydrotreating catalyst containing an S-containing organic additive.
2. Prior Art
Hydrotreating catalysts comprise hydrogenation metal components, generally a Group VI metal component such as molybdenum and/or tungsten and a Group VIII metal component, such as nickel and/or cobalt generally on an oxidic carrier. Before use, the hydrogenation metal components present in hydrotreating catalysts will generally be converted into their sulfides. This process is conventionally indicated as sulfidation or presulfidation. It is generally done before the catalyst is used in hydrotreating to ensure a stable reactor performance.
Hydrotreating catalysts containing S-containing organic additives are known in the art. The addition of the S-containing organic additive is often intended to preclude the necessity of a separate presulfiding step.
For example, European patent application 0 300 629 and European patent application No. 0 357 295 describe hydrotreating catalysts comprising a support impregnated with at least one member of molybdenum, tungsten, and/or Group VIII of the Periodic Table, and a mercapto-compound selected from mercaptocarboxylic acids, amino-substituted mercaptanes, di-mercaptanes, and thioacids. The S-containing additive is incorporated into the catalyst composition to obviate the necessity of presulfiding, or at least make the presulfiding less difficult. In particular, the S-containing additive is incorporated into the catalyst to obviate the necessity of dedicating the initial part of the reactor start-up to providing the catalyst with the amount of sulfur needed to attain equilibrium with the reaction environment, or to shorten the time necessary for doing so. Additionally, the necessity of spiking the feed with a sulfur-containing compound such as DMDS is lessened or obviated. Further, since all catalyst particles already contain S when they enter the unit, the homogeneity of the sulfided product will be improved.
European patent application No. 0 506 206 also describes a hydrotreating catalyst comprising an S-containing additive selected from the group of bi-mercaptanes, aminosubstituted mercaptanes, and thiocarboxylic acids. The S-containing catalyst is again intended to avoid the necessity of presulfiding. Some of the catalysts described in this reference are activated by a treatment with hydrogen at a temperature from room temperature up to 400° C., preferably 100-300° C.
Similar subject-matter is described in European patent application No. 0 338 788, and European patent application No. 0 289 211.
U.S. Pat. No. 5,139,990 describes a hydrotreating catalyst comprising a carrier and hydrogenation metal components which is treated with an aqueous medium comprising a water-soluble or water-miscible S-containing organic additive, followed by drying the resulting catalyst and activating it with hydrogen at a temperature of 100-600° C.
U.S. Pat. No. 4,636,487 describes a hydrotreating catalyst comprising a support and a hydroxymercaptide of one or more metals, which may be the reaction product of a mercaptoalcohol and one or more metal compounds. The catalyst may be activated with hydrogen at a temperature of 66-316° C.
European patent application No.0 496 592 describes a hydrotreating catalyst comprising a carboxylic acid and an organic sulfur compound which may be a mercaptocarboxylic acid. The amount of organic sulfur compound is so low that the catalyst still needs to be presulfided. No information is given as to how this presulfidation step should be carried out.
U.S. Pat. No. 5,045,518 describes a process in which a conventional hydrotreating catalyst is subjected to ex situ presulfiding followed by in situ presulfiding. Ex situ presulfiding is carried out by contacting the catalyst with a sulfur compound, e.g., by impregnation. The amount is 0.5-1.5 times the stochiometric amount. The sulfur compound may be present in a solvent, which may be water or an organic solvent, which may, e.g., be a gasoline fraction. The use of water-soluble sulfur compounds is preferred. After the impregnation there is a drying step to remove the solvent. The in situ sulfidation may be gas phase or liquid phase, with liquid phase being preferred.
U.S. Pat. No. 5,001,101 describes the preparation of a catalyst by incorporating metals into an alumina hydrogel, followed by shaping, drying, and calcination to prepare a catalyst. The catalyst is subsequently sulfided by a conventional sulfidation procedure, followed by activation at a temperature of at least 900° F. (482° C.). Conventional sulfidation procedures may include two-step sulfidation processes (col. 7, lines 55-62).
Although the activity of the catalysts containing an S-containing organic additive described in the above references is good, there still is room for improvement. Additionally, it has appeared that when the catalysts of the above references are brought into the hydrotreating unit, undesirable components such as acetic acid may be formed during the start-up. Additionally it was found that the start-up procedure is rather critical to obtain good results.
SUMMARY OF THE INVENTION
In one embodiment, our invention is a sulfidation process in which a catalyst composition comprising at least one hydrogenation metal component of Group VI and/or Group VIII of the Periodic Table, and an S-containing organic additive is contacted in two steps with hydrogen and a sulfur-containing compound in the gaseous phase, with the first step being performed at a temperature which is lower than that of the second step.
In a second embodiment, our invention is a catalyst obtained by the above process.
In a third embodiment, our invention is a process for hydrotreating a hydrocarbon feed by contacting the feed with the above catalyst at hydrotreating conditions.
Other embodiments of our invention encompass details about reactant compositions, process steps and conditions, etc., all of which are hereinafter disclosed in the following discussion of each of the facets of our invention.
DETAILED DESCRIPTION OF THE INVENTION
The Sulfidation Process
It appears that catalysts with a higher activity may be obtained if the catalysts containing an S-containing organic additive are sulfided by way of the process of our invention.
In the process according to our invention, the catalyst is contacted in two steps with hydrogen and a sulfur-containing compound in the gaseous phase, with the first step being performed at a temperature which is lower than that of the second step.
The sulfur-containing compound is H
2
S and/or a compound which is decomposable into hydrogen sulphide under the conditions prevailing during the contacting of the catalyst with hydrogen and a sulfur-containing compound. Examples of suitable components decomposable into H
2
S are mercaptanes, CS
2
, thiophenes, dimethyl sulphide (DMS), dimethyl disulphide (DMDS), and suitable S-containing refinery outlet gasses. The use of H
2
S alone is preferred. The skilled person knows how to select a sulfur compound which will decompose under the conditions applied.
The total amount of sulfur-containing compound which is incorporated into the catalyst in the process according to the invention, including the amount of sulfur added by way of the S-containing additive is generally selected to correspond to about 50-300%, preferably about 70-200%, more preferably about 80-150%, of the stoichiometric sulfur quantity necessary to convert the hydrogenation metals into Co
9
S
8
, MoS
2
, WS
2
, and Ni
3
S
2
, respectively.
The concentration of sulfur-containing compound in the mixture of H
2
and sulfur-containing compound is generally selected to be between about 1 and about 99 wt. %, preferably between about 10 and about 80%, calculated as H
2
S on the total of H
2
S and hydrogen. Of course, lower sulfur concentrations in this mixture will either lengthen the duration of the process or increase the required space
Akzo Nobel NV
Morris Louis A.
Wood Elizabeth D.
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