Presulfurization method of hydrogenation catalyst

Details Presulfurization method of hydrogenation catalyst Presulfurization method of hydrogenation catalyst

2000-01-24

2002-04-02

Bell, Mark L. (Department: 1755)

Catalyst, solid sorbent, or support therefor: product or process

Catalyst or precursor therefor

Sulfur or compound containing same

C502S155000, C502S167000, C502S168000, C502S216000, C502S219000, C502S220000, C502S221000, C502S222000, C502S223000

Reexamination Certificate

active

06365542

ABSTRACT:

FIELD OF THE ART
The present invention relates to a method for the presulfurization of a hydrogenation catalyst.
BACKGROUND OF THE INVENTION
The conventional method for presulfurizing hydrogenation catalysts is an in-situ (inside reactor) method of presulfurization, comprising: placing a catalyst having hydrogenation-active metal in oxidation state in a reactor and presulfurizing the catalyst at a high temperature by passing through hydrogen and hydrogen sulfide or hydrogen and a straight fraction oil containing carbon disulfide and dimethyl disulfide to convert the hydrogenation-active metal into sulfurization state. The in-situ method of presulfurization has the disadvantages of higher production costs, prolonged time for presulfurization and flammable and poisonous sulfides being used, thus causing environmental pollution.
Another method for presulfurizing hydrogenation catalysts is ex-situ (outside reactor) method of presulfurization, which means combining a hydrogenation catalyst and a vulcanizing agent prior to loading them into the reactor, then only introducing hydrogen or hydrogen and oils simultaneously to start up the presulfurization, and subsequently raising the temperature, thus completing the sulfurization activation process. Since the ex-situ method of presulfurization has advantages of simple operation, high efficiency and non-pollution, this method is used widely. In this ex-situ method of presulfurization, the vulcanization agent usually used is elemental sulfur and/or organic polysulfides.
In U.S. Pat. No. 4,089,930, a hydrotreating process of hydrocarbon raw materials is disclosed, which comprises contacting the hydrocarbon raw material with hydrogen and a hydrotreating catalyst as an elevated temperature to remove sulfur, nitrogen and oxygen there from, the improvement lies in that a sulfurized catalyst is used in the process, wherein said catalyst is obtained by presulfurizing the catalyst supported with metal oxides in the following steps: contacting the supported catalyst of metal oxides with elemental sulfur in the absence of hydrogen to allow at least a part of said elemental sulfur entering the pores in the catalyst. The sulfur-incorporated catalyst is contacted with hydrogen at 200~600° C. The method has advantages of low cost and high efficiency. However, since it is the nature of elemental sulfur to sublime easily and to be dissolvable in raw material oil, if there is no protective measure, the elemental sulfur in the catalyst will be very easily stripped off upon start-up, and as a result the catalyst can not be completely sulfurized and thus the catalyst will not have sufficient activity, and excessive sulfur will exist in the products. In some case as sulfur is stripped off, elemental sulfur will be condensed in the pipes downstream the apparatus to cause a sudden stop for blocked pipelines in production. Thus, it can be seen that, how to increase the sulfur retention degree in catalyst is a key problem which should be solved before commercial application of the ex-situ method of presulfurization when elemental sulfur is used as a vulcanizing agent.
To solve this problem of sulfur being stripped off, in EP 359,356 A1 two presulfurization methods of hydrotreating catalysts are proposed. One comprises: (1) contacting the catalyst with a powdered elemental sulfur at a temperature lower than 210° F. (about 99° C.) to allow said elemental sulfur entering essentially the pores in the catalyst to form a mixture; and (2) heating said mixture to a temperature in the range of higher than the melting point of elemental sulfur and below 390° F. (about 199° C.) in absence of hydrogen. Another one comprises (1) contacting the catalyst with a powdered elemental sulfur at a temperature lower than 210° F. (about 99° C.) to allow said elemental sulfur entering essentially the pores in the catalyst to form a mixture; and (2) mixing said mixture with at least one substance selected from a hydrocarbon solvent and an oil having a high boiling range to form a prewetted mixture, and the method also comprises further heating said prewetted mixture to a temperature higher than the melting point of sulfur. Using these methods mentioned above, the stripping loss of sulfur is decreased, and thus the retention degree of sulfur is increased.
In U.S. Pat. No. 5,215,954, two presulfurization methods of the catalyst containing metal oxides are disclosed, the first one comprises (1) contacting said catalyst with elemental sulfur by sublimation and/or melting at such a temperature as to allow said elemental sulfur entering essentially the pores in the catalyst, (2) heating the sulfur-incorporated catalyst at a temperature higher than 150° C. in the presence of liquid olefin. The second method comprises contacting said catalyst with the mixture of a powdered elemental sulfur and a liquid olefin, and heating the resultant mixture to above 150° C. By this method, stripping loss of sulfur is further decreased, and the retention degree of sulfur is increased.
In U.S. Pat. No. 5,681,787, a presulfurization method of hydrogenation catalyst particles containing at least one metal or metal oxide is disclosed, wherein the method comprises (1) contacting said catalyst with elemental sulfur at such a temperature as to allow at least a part of said elemental sulfur entering the pores in the catalyst, (2) contacting said catalyst with at least one of oxygen-containing hydrocarbons having at least 12 carbon atoms to obtain a catalyst having a decreased autothermicity.
Although the retention degree of sulfur is increased to a certain extent by using various methods mentioned above, it is still far from being enough.
CN 85107953A discloses a presulfurization method of catalyst, wherein said catalyst comprises at least one metal or non-metal oxide carrier and at least one active metal, in the first reaction stage, said catalyst is treated with at least one vulcanizing agent at 0-50° C. in the absence of hydrogen to allow the vulcanizing agent to permeate partially or completely through the pores in the catalyst, in which said vulcanizing agent is a polysulfide having a general formula as follows: R—S(n)—R′, wherein n is a number in the range of 3-20, R′ represents a hydrogen atom or other group similar or not similar to R group, both said groups represent respectively an organic group having 1-150 carbon atoms and may be one selected from the group consisting of saturated or unsaturated linear, branched or cyclic alkyl group, aryl group, alkylaryl group and arylalkyl group, and the vulcanizing agent is used in the form as it is dissolved in a solvent. Then the catalyst is subjected to drying treatment. Thereafter in the second reaction stage, the treated catalyst from the first reaction stage is further treated in the following procedures: (1) treating the catalyst in the absence of hydrogen but in the presence of an inert or non-inert gas at a temperature of 65-275° C. and a pressure of 0.5-70 bar for at least 5 minutes, then (2) treating the catalyst further at a temperature of at least 275° C. for at least 1 minute.
U.S. Pat. No. 5,139,990 discloses a preparation method of a catalyst for hydrotreating hydrocarbon raw materials, wherein the method comprises (1) preparing a catalyst which comprises a carrier material onto which one or more active metal or metal compounds for hydrotreating the hydrocarbon raw materials are deposited; (2) contacting the catalyst from the step (1) with a liquid medium containing an organic sulfur compound to introduce an effective amount of the organic sulfur compound into the catalyst, said organic sulfur compound is one selected from the group consisting of a salt of ethylene bis-(dithio carbamic acid), a salt of 2,5-dimetacapto-1,3,4-thiobiazole, thiourea, ammonium thiocyanate, dimethyl sulfoxide, 3,4-dithiaadipate 2,2′-dithioethylene glycol.
In both methods mentioned above, organic compounds of sulfur are used as the vulcanizing agent, but in the ex-situ method of presulfurization, there is a tendency to use elemental sulfur as the vulcanizin

Affiliated with

Also associated with

Rating

Presulfurization method of hydrogenation catalyst does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Presulfurization method of hydrogenation catalyst, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Presulfurization method of hydrogenation catalyst will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2865319