FR2647368A1 - Process for the pre-sulphurisation of a hydrocarbon treatment catalyst - Google Patents

Abstract

A process for the pre-sulphurisation (presulphiding) of a hydrocarbon treatment catalyst, effected in the presence of an ammonium disulphide solution, is characterised in that, conjointly with the ammonium disulphide, a sulphur-containing additive is used, which may in particular be a thiol, a thioether or an organic disulphide.

Description

The present invention relates to a method of presulfiding a hydrocarbon processing catalyst. The invention is an improvement of the process described in patent EP-B-153233 of the applicant.

 It is often desirable to carry out a sulphurization (generally called "presulphurisation") of the metals used in the composition of certain catalysts for refining and / or hydroconversion of hydrocarbons either when these catalysts are new or at the end of regeneration. of these catalysts before reuse.

Presulphurization of the new or regenerated catalysts is thus desirable for the use of these catalysts in the refining reactions, for example the desulfurization or hydrodesulfurization reactions of various species, for example, catalytic cracking or steam cracking gasolines of which - it is advisable, before use, to lower the sulfur content without modifying the octane number of these species or by modifying it as little as possible.

The catalyst used for this type of desulfurization or hydrodesulfurization contains a generally non-acidic support, for example an alumina or mixtures of alumina (US Pat. No. 4,334,982) or any other suitable support based on at least one oxide of a metal or metalloid (magnesia (US 4,311,632, USP 4,140,626), silica, silicalumines, silica-magnesies, silica-fluorinated, borated aluminas, clays, coals, aluminas fluorinated) this or these mixtures of carriers can at least partly be in amorphous form or in crystalline form (zeolites) and the catalyst additionally containing 0.2 to 30% of at least one active metal of groups VI, VIII or another chosen, for example, from the group consisting of cobalt, molybdenum, nickel and tungsten (US Pat. Nos. 3,732,155 and 3,804,748).

Sulfurization or presulphurization of regenerated catalyst is also desirable in hydroforming reactions of hydrocarbons (reforming in particular of a naphtha) and production of aromatic hydrocarbons ("aromizing"), for example the production of benzene, toluene and xylenes. (ortho, meta or para), either from unsaturated species or not (for example pyrolysis gasoline, cracking gas, in particular steam cracking (steam cracking), or catalytic reforming), or from of naphthenic hydrocarbons capable of dehydrogenation to become aromatic hydrocarbons.

The catalyst may contain, for example, at least one metal of the platinum family, that is to say a noble metal such as platinum, palladium, iridium, rhodium, ruthenium, osmium deposited on a suitable support (alumina, silica silica-alumina, fluorinated aluminas, fluorinated silicas, zeolite, etc ... or mixtures of such supports).

Sulfurization (presulphurisation) of a new or regenerated catalyst is still suitable, in certain cases, for the partial or total sulphurization of catalyst, also based on one of the aforementioned supports and at least one of the active metals already mentioned, for use in hydrocarbon conversion reactions such as hydrogenation, dehydrogenation, alkylation, hydroalkylation, dealkylation, hydrodealkylation, steam dealkylation, isomerization and hydrodemetallization reactions heavy loads.

The metals of the catalysts used in refining, hydrorefining or petrochemicals, whether new or regenerated, are most often in oxidized form, sometimes in metallic form (for certain metals, reforming catalysts in particular). Since the metals of these catalysts are often active only in the sulphurous or at least partially sulphurized form, it is therefore necessary for the refiner or petrochemist to carry out a sulphidation of the catalyst prior to its use.

At present, the regeneration of catalysts is increasingly done in a catalyst regeneration specialist, sometimes far from the industrial unit. However, it seems reasonable to think of returning to the refiner a product ready for use, which allows the original and effective process of the applicant described in EP.B.153233.

This process makes it possible, when starting the catalyst, to be subjected to the conventional activation reaction in the presence of hydrogen (generally above 100 ° C.), preferably at the site ("in situ"). the presence of hydrogen on the site, the sulphurization at the required stoichiometric or non-stoichiometric rate of the active metal or metals used in the composition of the catalyst. The process involves incorporating ammonium disulfide in the absence of hydrogen into the porosity of the new or regenerated catalyst.

In this process, the catalyst is generally impregnated "ex situ" in the absence of hydrogen with an aqueous ammonium disulfide solution.
S (NH4) 2 at a temperature between 0 and 50 OC, preferably between 10 to 35 OC and for example at room temperature so as to incorporate the appropriate degree of sulfur in the porosity of the catalyst, the treatment of the catalyst being then followed by drying of this catalyst for example at a temperature below 120 ° C. and preferably between 95 and 115 ° C. Above 120 ° C., it was found that the sulfur was partially removed from the catalyst.

One of the advantages of the process is that it can presulfurize the catalyst only in the presence of an aqueous solution. It has been proposed by the plaintiff in US.A. 4,719,195 introducing organic polysulfides into the porosity of the catalytic mass; However, the latter method has the disadvantage of operating the presulfuration in the presence of an organic solvent of "white spirit" type more difficult to remove than liteau end of the process. The present process, moreover, has the advantage of being able to use the commercial solution of ammonium sulphide as it is.

It has now been discovered, in the context of the present invention, a means for improving the presulphurization of the catalyst, which means in particular a longer stability of the catalysts in long-term tests.

This means consists in operating the incorporation of ammonium sulphide into the porosity of the catalyst, in the presence of at least one particular sulphurized additive.

5 to 50% by weight, preferably 10 to 40% by weight, and more particularly 15 to 30% by weight of the additive or additives selected with respect to the weight of sulphide introduced into the catalyst, will advantageously be used.

The additive (s) may be added, for example, with the ammonium disulfide solution, either in the pure state or dissolved in a suitable solvent, especially water.

The rible of this additive is to increase the incorporation of sulfur into the catalyst. In a preferred method ammonium disulfide can be introduced onto the catalyst during a first impregnation.

Then during a second impregnation is added the additive (in aqueous solution or not) alone or in admixture with ammonium disulfide.

Thus, in a more particular way, and especially when it wishes to convert all the oxides of the promoter metals contained in the catalyst into sulphides, the process then consists of (a) impregnating the catalyst at a temperature of between 0 and 50 ° C.
its impregnation volume with an aqueous disulfide solution
S (NH4) 2, (preferably between 10 and 35 OC), (b) drying the catalyst at a temperature below 120 OC, and
preferably between 95 and 1150 ° C, (c) re-impregnating (between 0 and 50 ° C, preferably between 10 and 50 ° C).
35 OC) at least a second time the catalyst at its volume
impregnation or at a lower volume, depending on the quantity
of sulfur to be introduced into the catalyst by a mixture of
aqueous solution of ammonium disulfide S (NH4) 2 and an additive
according to the invention, (d) drying the catalyst at a temperature below 130 OC and
preferably between 90 and 120 OC and more particularly in the vicinity
100 OC.

If necessary, if necessary, in the case where large quantities of sulfur must be introduced into the catalyst, further impregnation of the catalyst with an ammonium disulfide solution and / or the additive will be carried out, each of them being followed by drying at a temperature below 120 OC.

It may thus be necessary to perform several impregnations because the pore volume of the catalyst is not sufficient to absorb during the first impregnation all the theoretical aqueous solution of ammonium sulphide and / or additive containing the amount, stoichiometric or not, sulfur that it is proposed to introduce into the catalytic mass (a commercial solution of ammonium sulphide contains maximum 20% by weight of sulfur and then want to concentrate such solutions would result in the decomposition of ammonium disulfide).

The drying which follows the first impregnation of ammonium disulfide is preferably carried out in a gas containing molecular oxygen and in particular in air.

The invention can thus be carried out in the presence of a sulphide additive selected from the group consisting of thiodiazoles, thioacids, thioamides, thiocyanates, thioesters, thiophenols, thiosemicarbazides and thioureas. By way of example, mention may be made of thiobenzoc acid, 2-thiocresol, 3-thiocresol, 4-thiocresol, 3,3 'thiodipropionic acid, 3,3' thiodipropionitrile, 2,3,6-thiocresol trimethyl thiophenol, methyl thioglycollate, 4-methyl-3-thiosemicarbazide, naphthalene 2-thiol, phenyl isothiocyanate, 2-phenyl thiophenol, thioacetamide, thiobenzamide, 2,6-dimethyl thiophenol, 3,5-dimethyl thiophenol, 2,2'-dinitrodiphenyl disulphide, 2,5-dithiobiurea, 11-ethyl thioglyacollate, 2-methoxy thiophenol, 3-methoxy thiophenol, 2-methyl-5-mercapto-1,3,4-thiadiazole, amidinothiourea, 2-amino ethyl-1,3,4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 2-amino thiophenol, benzene 1, 3-dithiol, 3-chloro thiophenol and 2,5-dimercapto 1,3,4-thiadiazole.

où n et m sont des nombres entiers, R1, R2, R3, R4, identiques ou différents sont des atomes d'hydrogène ou des radicaux organiques alkyle, aryle, aralkyle, alkylaryle etc... ayant de préférence 1 à 20 ; de préférence 1 à 6 atomes de carbone par molécule ; de préférence n = 1-10 (par exemple 1-2) et m = 1-10 (par exemple 1-2).But the invention can also be carried out in the presence of other types of sulfur additives. It will thus be possible to mention the mercapto-alcohols of formula:

where n and m are integers, R1, R2, R3, R4, which may be identical or different, are hydrogen atoms or organic radicals of alkyl, aryl, aralkyl, alkylaryl, etc., preferably having 1 to 20; preferably 1 to 6 carbon atoms per molecule; preferably n = 1-10 (for example 1-2) and m = 1-10 (for example 1-2).

By way of example, mention may be made of 2-mercaptoethanol, 1-mercapto-2-propanol, 1-mercapto-2-butanol, 3-mercapto-1-propanol, 1-mercapto-2-hexanol, 2-mercaptocyclohexanol and 2-mercaptocyclopentanol. , 3mercaptobicyclo (2,2,1) -heptane-2-ol-mercapto-2-pentanol, 1-mercapto-2-phenyl-2-ethanol, 3-mercapto-3-phely-propan-1-ol, 2-mercapto 3-phelypropan-1-ol, thioglycerol, 9-mercapto-10-hydroxyoctadecanoacid acid and 10-mercapto-10-hydroxyoctadecanoacid acid. More particularly, compounds of formula HS-CH 2 -CH 2 OH (2 mercaptoethanol) and HS-CH 2 -C (C 6 H 5 H -OH (1-mercapto-2-phenyl-2-ethanol) are mentioned.

The thiols (thioalcohols, mercaptans, thiophenols) of formula R1-SH where R is an organic radical, the thioethers of formula R1-S-R2 and the organic disulfides of formula R1-SS-R2 can be used in a more general manner. .

Mention may thus be made of alkyl mercaptans (such as n-butyl mercaptan, n-hexyl mercaptan), monothioglycols (such as monothioethylene glycol), dithioglycols such as dithiopropylene glycol, aryl mercaptans already mentioned above (thiophenols) (such as thiophenol, thiocresols), dithiobenzenes (such as dithioresorcin), heterocycles substituted with mercapto groups (such as mercaptopyridine, mercaptopyrimidine, etc., etc.). As an example of thioethers, mention may be made of dialkyl sulfides (such as din-butyl sulphides, di-tert-butyl sulphides, dihydroxyalkyl sulphides (such as thiodiethylene glycol (S (CH 2 CH 2 OH) 2), thiodipropylene glycol, and the like; diaryl sulphides (diphenyl sulphide, etc.); dialkyl sulphides (dibenzyl sulphide, etc.), alkyl ethers, thiophenols (thioanisole, etc.), cyclic thioethers and their substituted derivatives (ethylene sulphide, thiophene, thiazole, thiopyrone, thioxanthone, t hioxanthydrol, 1, 4 thioxane etc ..., the alkyl salts of heterocycles substituted with mercaptans (2-methylthio 4,6-diamino pyrimidine etc ...).

Among the families of the above compounds, mention will be made more particularly of dimethyl sulfoxide, ethyl thiol ethanol, thio glycolic acid, di thio glycol and organic disulfides of formula in particular HO-R 1 -SR-R 2 -OH or H 2 ( Wherein R1 and R2 are defined as above, wherein x, x 'and x ", which are the same or different, are an integer.

Mention may be made more particularly by way of example of diethanol bisulphide or 2,2-dithiobis ethanol of formula
HO-C2H4-SS-C2H4-OH soluble in particular in water, glycols and polyglycols.

Examples
The purpose of the tests is to prepare an easily manipulated catalytic charge, reduce investment time to obtain an economically viable yield, be able to rely on the ex-situ regeneration plants and save the refiner time while facilitating the reworking of the catalytic charge.

It is recalled that the base of the sulphidation of a catalyst according to the process of the invention remains the same as in the prior art, namely the use of a mixture of hydrogen and hydrogen sulphide:

The principle of the process consists in charging the catalyst with ammonium sulphide mixed or not with DEDS (diethanol disulfide). This is done by adsorption of this or these compounds in the porosity of the catalyst.

The catalyst thus treated is subsequently activated in the reactor of the refinery by passage of heated hydrogen for example between 80 and 200 OC. The sulphurized product releases H2S, the sulphidation of the oxides then takes place according to the known techniques mentioned above.

Some tests were made on a new KETJEN 165 / 1.5 E catalyst, calcined at 550 OC, new or regenerated.

Example 1 (comparative)
The sulphurizing agent (or reagent) tested is ammonium disulfide.

The manipulation is carried out by immersing a given amount of catalyst in an excessive volume of the reagent. The impregnation lasts 1 hour.

It is proposed to introduce ammonium sulphide into the catalyst
KETJEN new or regenerated whose support is alumina and which contains 15.4% by weight of MoO3 molybdenum oxide and 4.23% by weight of cobalt oxide CoO. The purpose of the operation is that, later, on the site where this catalyst will be used, a hydrogen pretreatment of the catalyst can convert all the molybdenum oxide to molybdenum sulphide MoS2 and all the cobalt oxide to sulphide. Cobalt Coqs8 formula. The
Porous lume of catalyst is 46 ml per 100 grams of catalyst
It is possible to calculate the weight of sulfur (molecular weight: 32) which should be introduced into the porosity of the catalyst in order to transform all the oxides of molybdenum and cobalt into sulphides (MoS2 and Coqs8) 15.4 g of oxide Molybdenum (molecular weight of MoO3: 144) in 100 grams of catalyst corresponds to (see reaction (1) on page 9) 15.4 ---- x 2 x 32 = 6.844 g of sulfur in these 100 grams of catalyst.

144 does not even, 4.23 g of cobalt oxide (molecular weight: 75) in 100
These catalysts correspond to (see reaction (2) on page 9): ## STR1 ## in which these grams of catalyst are present.

 It is therefore necessary to incorporate a total of 6.844 + 1.604 = 8.448 g of sulfur in 100 grams of catalyst. To carry out this operation, use will be made of a commercial 20% aqueous solution of ammonium sulphide (NH 4) 2 S (molecular weight: 68); 100 ml of such a solution closment: 0.294 molecule of (NH4) 2S is 0.294 sulfur atom or 9.41 g of sulfur. Since 8.448 g of sulfur must be introduced into 100 g of catalyst, 89.77 ml of said commercial solution should be used per 100 g of catalyst, this volume thus corresponding to approximately twice the pore volume of the catalyst (46 ml per 100 g), so the need to perform here two successive impregnations of the catalyst.

During a first impregnation, 46 ml of the commercial solution of ammonium sulphide are introduced into the catalyst at ordinary temperature. It is dried at 105 ° C. for about two hours in air. A second impregnation is then carried out using 46 ml of the commercial solution and dried at 100 ° C. for about two hours, under nitrogen.

The catalyst contains at this stage 8.6 grams of sulfur per 100 grams of catalyst.

It has been found that by drying at 150 ° C., the catalyst contains only 5.18% sulfur and that the catalyst contains 5.51% of sulfur by drying at 200 ° C.

Various conventional analyzes make it possible to conclude that sulfur is present in the catalyst in the form of polysulphide.

The results obtained on the KETJEN K 165 / 1.5E catalyst treated with ammonium disulfide are the following: Loss on ignition at 500 OC (PAF at 500 OC)
- before treatment: 0.81 Z
- after treatment: nitrogen: 26.76 Z
Carbon and sulfur analysis on the impregnated catalyst.

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<tb>(<SEP>:<SEP> processing <SEP>: <SEP> processing <SEP>)
<tb>(<SEP>:<SEP><SEP>:<SEP> under <SEP> nitrogen <SEP>)
<tb>(<SEP>:<SEP>:<SEP>)
<tb>(<SEP> S <SEP> Z <SEP>: <SEP> 0.38 <SEP>: <SEP> 8.76 <SEP>)
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<tb>(<SEP> C <SEP>% <SEP>: <SEP> 0.08 <SEP>: <SEP> 0.12 <SEP>)
<Tb>
In view of these results (in particular the values of PAF at 500 ° C.), it can be said that the catalyst is on average impregnated with 20% of ammonium disulphide, ie 8.45% of sulfur by weight of dry and oxidized catalyst, which corresponds to the desired goal.

The activation of the previously treated catalyst is carried out by passing a stream of hydrogen at 150 ° C. through a bed of impregnated polysulfide catalyst (at 30 bars).

When the bed has reached 130 OC, the reaction starts and the temperature rises to about 150 OC.

The catalyst becomes black, this is due to the metal sulphides formed.

The analysis of the sulphurized catalyst gives as a value of sulfur 8.50%.

Example 2 (according to the invention)
The previous tests are repeated as indicated above. However, here during the second impregnation, 25 ml of the commercial solution of ammonium disulfide is used and the theoretical complement necessary for the stoichiometric sulphidation of the catalyst is provided by an aqueous solution of diethanol disulfide.

At the end of the activation of the catalyst, the analysis of the sulfurized catalyst also gives a sulfur value of 8.50 Z.

It will be noted later that the stability of the activities is improved notably in the long-term tests (several hundred hours in the pilot units).

Claims (3)

1. - Process for treating a new or regenerated catalyst, containing  a support based on at least one oxide of a metal or a metalloid  and at least one active metal, produced in the absence of hydrogen and  treating said catalyst with an aqueous solution of  ammonium disulfide at a temperature of 0 to 50 OC, in  presence of at least one sulfur additive selected from the group  consisting of thiodiazoles, thioacids, thioamides,  thiocyanates, thioesters, thiophenols,  thiosemicarbazides, thioureas, mercapto alcohols of formula

 of formula R1-S-S-R2 where R1 and R2 are defined as above.  and R2 are defined as above and organic disulfides  R is an organic radical, thioethers of formula R1-S-R2 where R1  alkyl, aryl, aralkyl, alkylaryl, thiols of formula R1-SH where  different are hydrogen atoms or organic radicals  where n and m are integers, R1, R2, R3, R4, the same or 2. - Process according to claim 1 for treating a new catalyst  or regenerated containing a support based on at least one oxide of one  metal or metalloid and at least one active metal, said method  consisting  (a) impregnating the catalyst at a temperature between 0 and  50 OC at its impregnation volume with an aqueous solution of  ammonium disulfide,  (b) drying the catalyst at a temperature below 120 OC,  (c) impregnating the catalyst again at least a second time  its impregnation volume sou to a lower volume, by a  aqueous solution of ammonium disulfide and at least one said  additive,  (d) drying the catalyst at a temperature below 130 OC. 3. - Method according to one of claims 1 and 2 wherein the weight  of additive (s) used represents 5 to 50% of the weight of  sulfur introduced into the catalyst.