FR2572309A1 - Process for presulphurising a catalyst for hydrocarbon treatment - Google Patents

Abstract

Process for sulphurising a catalyst especially a refining catalyst containing a support and active metal oxides. In a first stage a sulphur compound based on an organic polysulphide is introduced into the catalytic mass. In a second stage the sulphurisation of the active metal oxides is carried out first of all in the absence of hydrogen at a temperature below 275 DEG C and then the activation of the catalyst is carried out at a temperature above 275 DEG C.

Description

PROCESS FOR PRESULFURING CATALYST FOR PROCESSING HYDROCARBONS

The present invention relates to a method of presulfiding a catalyst for treating hydrocarbons and / or preconditioning a catalyst and then being presulfided.

It is often desirable to carry out a sulphurization (generally called "presulphurisation") of the metals used in the composition of certain hydrocarbon refining and / or hydroconversion catalysts, 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 waf- or hydrodesulphurization / fining, for example the desulfurization reactions of various species, for example catalytic cracking or cracking gasolines. steam which, before use, it is appropriate to lower the sulfur content without modifying the octane number of these species or by modifying it as little as possible. Such desulfurization reactions, generally carried out in the presence of hydrogen, between 200 and 4000 ° C., at a pressure of between, for example, 5 and 60 bars, with a space velocity (expressed in m 3 of liquid injected charge per m 3 of catalyst and per hour) of between 0.5 and 15, with a partial pressure of hydrogen ranging from 4 to 60 bars, the charge being for example a gasoline generally distilling between 30 and 2200 C and possibly having a bromine number between 40 and 80 (g / 100 g), containing about 15 to 45%, by volume, of olefins (essentially monoolefins minor amounts of diolefins) and 15 to 25% of aromatic hydrocarbons.

of desulfurization or /
The catalyst used for this type / 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. demetalle (magnesia (USp4, 132 - silica-alumina silica-fluorinated 632, USP 4 140 626), silica, silicemagnesies, boron aluminas, clays, coals, fluorinated aluminas) this or these carrier mixtures can at least partially in the form of amorphous 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 other chosen for example from the group consisting of cobalt, molybdenum, nickel and tungsten (USP 3,732,155 and 3,804,748). A pair of two of these metals, for example one of the cobalt-molybdenum, nickel-molybdenum, cobalt-tungsten, tungsten-molybdenum, cobalt-nickel, nickel-tungsten pairs, is generally used. It is still possible, for example, to use a noble metal of group VIII of the platinum family: Pt, Pd .... US 4,098,682.

Thus, before being used, the catalyst, new or regenerated, is generally subjected in the prior art to sulphurisation (presulphurization) carried out in the hydrodesulfurization reactor. With this sulfurate, it is possible to include in the catalyst, for example, approximately 50 to 110% of the stoichiometric quantities of sulfur calculated on the amounts of sulphide of formula (according to the metals present), Co9S8, Mo S2, WS2 and Ni3.
S2.

This sulphurization (presulphurization) is carried out, in the prior art, at a temperature near or higher (thus greater than lBO C and more particularly above 250C C) relative to the reaction temperature chosen for the hydrodesulfurization reaction, for a few hours, using a mixture of hydrogen sulphide generally diluted in hydrogen (proportion of hydrogen sulphide in hydrogen of the order of 0.5 to 5% by volume) with an adequate space velocity for example, from about 1,000 to 3,000 liters of gas under normal conditions of temperature and pressure per liter of catalyst per hour (USP 4,334,982). The actual sulfurization (or presulphurization) can be carried out by temperature level
(French Patent No. 2,476,118). Various sulphurizing agents other than hydrogen sulphide (H 2 S) and for example a sulphurized compound of the mercaptan family, carbon disulfide (CS 2), sulphides or disulfides, thiophenic compounds and preferably dimethylsulfide (DMS) and dimethyl disulphide (DMDS).

Sulfurization or presulphurization of regenerated catalyst is also desirable in the hydrocarbon hydroreforming reactions (reforming in particular of a naphtha) and in the production of aromatic hydrocarbons ("Aromizing"), for example the production of benzene; toluene and xylenes (ortho, meta or para), whether from unsaturated or unsaturated species (for example pyrolysis, cracking, in particular steam cracking, or catalytic reforming) or again from naphthenic hydrocarbons capable of dehydrogenation to be transformed into aromatic hydrocarbons.

The general conditions of these reactions are generally as follows: average temperature of between 400 and 600 ° C., pressure of between 1 and 60 bars, hourly velocity of between 0.1 and 10 volumes of liquid naphtha per volume of catalyst and the rate of recycling between 0.5 and 20 moles of hydrogen per mole of filler.

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). The total content of noble metals is, for example, between 0.1 and 5% by weight relative to the catalyst. The catalyst may also contain at least one halogen (chlorine, fluorine, etc.) with a content of from 0 to 15%. Optionally, the catalyst contains at least one promoter metal chosen from the most diverse groups. of the periodic table of the elements, the weight content of promoter metal varying for example between 0.1 and 15%. Mention may thus be made of the metals of groups VIII, VI A and VI B, IB and II B, III A, IV A , VA and
VB, IV B, III B, IA and IB as well as the metals of the lanthanide family: more particularly, in addition to noble or non-noble metals of group VIII, copper, silver, gold, germanium, tin, indium, thallium, manganese, rhenium, tungsten, molybdenum, niobium and titanium.

For these catalytic reforming or aromatic hydrocarbon production reactions, the sulfurization of the new or regenerated catalyst is accompanied by a reduction of the catalyst with hydrogen and takes place at the top of the reactor or in the vicinity of the reactor head. The temperature in the sulphurization zone is imposed by the temperature at which the reduction takes place, generally between 480 and 6000 C.
in most of the cases. the difficulty of this type of sulphurization on the
site, that is to say in the vicinity of the reactors, has led to
sulphurization work, which is often tedious, though effective (USP
4172027).

in the prior art /
The sulphurizing agent used is either pure hydrogen sulphide or
diluted with hydrogen or with gaseous hydrocarbons,
dimethyl disulphide diluted with hydrogen or other sulpho compounds
such as alkyl sulphides or alkyl mercaptans, diluted with
lthydrogene. The pressure used is that which prevails in the reactor
reforming or producing aromatic hydrocarbons, the duration of
the reaction varies from a few minutes to a few days depending on the
operating conditions chosen. (see USP 4,172,027).

Sulphurisation (presulphuration) of a cata
In some cases, the new or regenerated
partial or total sulphidation of catalyst, also based on a
already cited supports and at least one of the active metals already mentioned,
used in reactions, hydrocarbon conversions such as
the hydrogenation, dehydrogenation, alkylation,
hydroalkylation, dealkylation, hydrodealkylation,
dealkylation with water vapor, isomerisation and hydroetallic acid
sation (or deinstallation) of heavy loads.

Sulphurisation or presulphuration, when necessary
advantageously according to one or the other of the techniques of
the prior art recalled above.

The metals of catalysts used in refining, hydrorefining or petrochemicals, whether new or regenerated, are most often in oxidized form, sometimes in metallic form (for some 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 ready-to-use product, which is allowed by the efficient process of the European patent application No. 84,400,234 in which a sulfur compound is incorporated into the catalytic mass, which compound, causes the sulfuration or presulfiding of the catalyst when, subsequently, in the reaction zone (charge treatment zone) or in the immediate vicinity of the reaction zone, the catalyst will be brought into contact with hydrogen.Of course, the incorporation of said sulfurized compound may, if desired, be carried out near the industrial unit or even at the catalyst treatment site; the process for incorporating said sulfurized compound can be carried out off-site also on a new or regenerated catalyst before it is used in the industrial unit.

More precisely, in the European patent application No. 84.400234, the process for sulphurizing the catalyst is therefore characterized by a preliminary step known as incorporation into the catalytic mass of a sulfur compound of a particular nature.

The preliminary step of introduction of a sulphide compound, arbitrarily called "off-site" or "ex situ" pretreatment, whether carried out near the site of the industrial unit or at a greater or lesser distance geographically of the industrial unit (where the catalyst has been regenerated or where it has been manufactured for example) is no longer anyway in the immediate vicinity of the reactor (it is written arbitrarily "in situ") that is - say at the head of the reactors or in zones more or less in direct communication with these reactors, requiring to operate under operating conditions (temperature, pressure or other), imposed at least partly by the operating conditions of the reactors them or annexes of these reactors (pre-hydrogenation zone of the catalyst for example).

In summary, the invention of the European patent application 84.400234 relates to a process, allowing, when the catalyst is subjected from its start preferably on the site ("in situ") to the conventional reaction of activation in the presence of hydrogen , (generally above 1000C), then proceed, thanks to the presence of hydrogen on the site, to sulphurization at the required stoichiometric or non-stoichiometric rate, of the active metal or metals used in the composition of the catalyst. The process consists of incorporating in the absence of hydrogen into the porosity of the new or regenerated catalyst at least one sulfurizing agent of the general formula R - (n) - R ', where R, R' and n are defined below .

The sulphurization of the catalyst can thus be done as follows: in a first step carried out "ex-situ", in the absence of hydrogen, the catalyst is treated with at least one sulphurizing agent so as to incorporate partially or totally this agent in the porosity of the catalyst, the sulphurizing agent being a polysulfide of general formula R - (n) - R 'said sulphurizing agent being used in solution in a solvent in a second stage, carried out "in situ , and preferably above 1500C, a catalyst activation step is carried out in the presence of hydrogen, the required amount of sulfur being fixed by the presence of hydrogen on the metal or metals entering the composition of said catalyst.It is this last step that is perfected in the present invention.

The object of the European patent application 84-400234 is therefore to conduct "ex-situ" the presulphurization of the catalysts by incorporating all the necessary amount of sulfur and only the necessary amount of sulfur required by the user. The catalysts are therefore delivered to the refinery or any other unit, thus preconditioned to be presulfided.

The refiner, or any other user, therefore only has to reactivate this catalyst in the presence of hydrogen at a temperature of, for example, 100 to 2000 ° C. for a desulfurization catalyst, from 400 ° to 6000 ° C., for a reforming catalyst. catalytic or aromatic hydrocarbon production, in order to react the sulfur on the contained metals and immediately start the reaction of refining or hydrocarbon conversion by injection of the charge to be treated.

In the polysulfide of formula R-S (n) -R n is an integer from 3 to 20, preferably from 4 to 8 and more preferably from 5 to 7; R and R ', identical or different, represent organic radicals each containing 1 to 150 carbon atoms per molecule, preferably 10 to 60 carbon atoms and more particularly 15 to 30, these radicals being chosen from the group consisting of radicals alkyl, that is to say saturated or unsaturated, linear or branched or naphthenic type, aryl radicals, alkylaryl radicals and arylalkyl radicals, these various radicals may comprise at least one hetero atom. R 'optionally may also be a hydrogen atom.

où R" est un radical dodécyle.As a preferred example of polysulfide, mention may be made of ditertiododecylpolysulfide (n = 5) of formula

where R "is a dodecyl radical.

This product is marketed for example by Elf Aquitaine under the name
TPS 32, in particular because it contains about 32% by weight of sulfur.

où R" est un radical nonyle.There may also be mentioned ditertiononylpolysulfide (n = 5) of formula

where R "is a nonyl radical.

This product is marketed by Elf Aquitaine under the name TPS 37, in particular because it contains about 37% by weight of sulfur or by
PENWALT under the name of TNPS.

For procedural reasons, it is of course possible to use these sulphurization agents of the polysulphide type alone or as a mixture with one another in carefully chosen proportions.
The first step mentioned above is carried out in the absence of hydrogen and makes it possible to obtain with a very high degree of precision the degree of total or partial sulphurization requested by the user. This sulfur incorporation is carried out between 0 and 50 ° C and preferably between 10 and 350 ° C and more preferably at room temperature.

The sulphurizing agent is used, diluted in a suitable solvent which depends in particular on the nature of the sulphurizing agent that is to say of R or R ', radicals which determine the sulfur content incorporated in the catalyst generally by capillarity or porosity. The sulphurization processes vary in fact according to the sections to be treated later in the presence of the catalysts treated in accordance with the invention. The solvent chosen can thus be one of the following solvents used alone or mixed together - a light gasoline boiling for example between about 60.degree. and 950C - a hexane type gasoline boiling between about 63 and 680.C - a type F gasoline boiling between about 100 and 1600C and
generally containing 10 to 20% aromatic hydrocarbons,
example 15%, by volume - a type of essence "white spirit" boiling between about 150 and
2500C and generally containing 14 to 22% hydrocarbons
Aromatic, for example 17%, by volume, - or any hydrocarbon cut or not, equivalent to the species
preceding.

Subsequently, at the site or near the site (on which the catalyst will be used for the treatment of various fillers), during the conventional activation reaction, carried out in the presence of hydrogen (second stage of the patent application process) European 84-400234), the sulphurizing agent introduced into the catalyst in predetermined quantities, will be capable of giving rise to hydrogen sulphide which, in the presence of hydrogen, will lead to the desired sulphide or sulfides of the metal or metals present in the catalyst according to for example the following schematic exothermic reactions (1) (2) (3) with regard to, by way of example, the sulphurizations of molybdenum, cobalt and nickel

The use of a suitable solvent, in which the sulphurizing agent is dissolved, makes it possible to play on the latent heat of vaporization of the chosen solvent, thus to absorb at least part of the exothermicity of the sulphurization reaction.

At the end of the sulfur deposition, at least part of the solvent remains in the catalyst. It is therefore possible to remove this solvent (by stripping with liquid nitrogen for example, or by any other means).

But this solvent left in the catalyst can be removed later and without any damage, in the reactor of use of the catalyst, that is to say on the site ("in situ").

In the first step, the volume of polysulfide and of the chosen solvent should preferably be about a value equal to the pore volume of the catalyst bed to be treated: thus, for example, per 100 g of regenerated or new catalyst (oxidized form ) It is therefore necessary to put about 9 grams of polysulfide sulfur in about 45 cm3 of polysulfide total mixture plus solvent (white spirit for example).

The adsorption of this polysulfide is generally done in ambient air.

The catalyst may then be optionally dried under a stream of hot air and then conditioned to be shipped, according to a preferred method, to the refiner.

In the present invention, it has been found that during a first part of said second stage, the presence of hydrogen is not only unnecessary but, on the contrary, its absence is even desirable, provided, however, that during the end this second step, performed ex situ or in situ, and optionally in the presence of hydrogen, the catalyst is heated for at least about one hour, at a temperature at least equal to 2750C. The first part of this second stage is carried out in situ or ex situ. Thus the first part of the second stage is carried out in the absence of hydrogen under an inert gas atmosphere (nitrogen, argon, helium, etc.) for about 1 to 3 hours at a pressure of between about 0.degree. 5 and 70 bar, at a temperature between 75 and 2750C, preferably between 85 and 2600C and more particularly between 95 and 1500C.Au the second part of the second step, the catalyst is heated to a temperature equal to at least 2750 C, preferably between 300 and 4000C and for example around 3500C, for at least about one hour in the presence of hydrogen.

This step part is generally carried out in situ and can be confused with the start or the actual start of the refining or petrochemical reaction for which the catalyst prepared according to the present invention is designed, in the case precisely where such a reaction is made above 2750C.

When the temperature chosen for the refining or petrochemical reaction is less than 2750 ° C (for example, it may be the case for hydrodesulphurations of gasolines or kerosines), it is then sufficient to lower the temperature used in the second part of the second step after this step at the appropriate temperature for this reaction.

It has been found that in the first part of the second stage, in spite of the absence of hydrogen, the catalyst is sulphidized, that is to say that the oxides of the active metals of the catalyst are converted into sulphides according to the reactions. chemical data given above. This phenomenon is easily observed by catalyst analysis, which also becomes black. On the other hand, chemisorption tests show that as long as the catalyst does not reach the temperature of 2750 ° C. and does not remain for at least about one hour at at least 27 ° C., this catalyst remains devoid of catalytic activity (see Example 4 below). -after).

In short, during the first part of the second stage, the oxides of the active metals are transformed into sulphides, the catalytic activity of these sulphides being manifested only when the catalyst reaches approximately 2750C, possibly in the presence of hydrogen (second part). of the second stage). Proceed according to the technique of the invention shows several advantages immediately. The first part of the second stage being carried out in the absence of hydrogen, the admission of hydrogen is later than in the process of the European patent application No. 84-400234, hence here a lower consumption of hydrogen The first part of this second stage is no longer exothermic, which is very appreciable (especially from the point of view of safety) for the refiner if this first part of the second stage is carried out in situ. At the end of the first part of the second stage, the catalyst is absolutely not pyrophoric until it has reached the temperature of approximately 2750 ° C., that is to say it is incapable of adsorbing oxygen (exothermic process due to the pyrophoricity of sulphurized catalysts). This catalyst is therefore insensitive to air and can be handled without any particular precaution. So, if desired, this first part of the second stage (transformation of the oxides of the active metals into sulfides) can be carried out at the site of the regeneration (" ex situ ") and then, the catalyst, possibly previously dried, insensitive to air, is transported by truck or by airplane for example, not only presulfide as taught in the European patent application 84-400234 (sulfur incorporated in the pores catalyst in the form of organic polysulfide) but already sulphured, from the regeneration site to the refiner or the petrochemical, the latter then having only to put the catalyst in the refining or petrochemical unit for which the catalyst has been designed, and bring the catalyst to a temperature of at least 275 ° C for at least one hour, possibly introducing hydrogen (essential anyway for the continuation of the operation of the unit). At this stage, other advantages appear as well for the one who carried out the regeneration of the catalyst as for the user of the catalyst, in the case where the first part of the second stage is made "ex situ": during this first part of the second stage, the solvent in which the organic polysulfide was dissolved evaporates (white spirit for example). So this solvent remains on the regeneration site and is recovered by the one who proceeded to the regeneration and presulfuration of the catalyst. The refiner or the petrochemist do not themselves have to provide extraction lines for this solvent. Similarly, the water that can form in the sulphidation reactions of the active metal oxides is eliminated on the regeneration site and the refiner or petrochemist do not have to provide in their units, water removal pipes.

During the second part of the second stage (activation), the catalyst then becomes capable of adsorbing oxygen, thus activating the refining and petrochemical reactions. This activation can be carried out in situ, that is to say in the refining or petrochemical reactor but also ex situ, if for example the wish is felt, if only because, when the refining reaction is made at low temperature, the reactor chosen for such a reaction was not built to withstand high temperatures (mechanical stresses); and it has also been found that when the catalyst undergoes the treatment of the present invention, its activity is improved not only with respect to conventional sulfurization techniques (for example by H2S) but also with respect to the technique of the European patent application. -400,234. Thus, in general, the activity of a catalyst is inversely proportional to the volume of catalyst used to carry out a refining reaction. However, operating according to the invention, it has been found that in order to obtain, on the same refining reaction, identical performances, about 5% less catalyst volume is used relative to the volume used of a sulphurized catalyst by H 2 S, and about 2% less catalyst volume relative to the used volume of a sulfurized catalyst according to the method of European Patent Application 84-400234.

During the first stage of the catalyst treatment process, the "ex situ" incorporation of the polysulfide into the porosity of the catalyst can be carried out in the presence of at least one additive having reducing properties and which is selected in the present invention. group consisting of aldehydes containing 4 to 14 carbon atoms per molecule (and preferably 5 to 12 carbon atoms), the ketones or polyketones containing 3 to 18 (and preferably 5 to 12) carbon atoms per molecule, the ethers containing 5 to 14 (preferably 6 to 12) carbon atoms per molecule, the alcohols or polyalcohols containing 5 to 14 (and preferably 6 to 12 carbon atoms per molecule and organic acids or polyacids containing 3 to 14 (and preferably 6 to 12 carbon atoms per molecule).

0.4 to 8% by weight, preferably 0.8 to 4% and more particularly 0.9 to 3% by weight of the additive or additives selected with respect to the weight of the polysulfide or polysulfides used, will advantageously be used.

The additive (s) may be added, for example, with the solution of the polysulfide (s) used, either in the pure state or dissolved in a suitable solvent. This solvent may be of the same type as the solvent chosen for dissolving the polysulphide, namely, for example a light gasoline boiling for example between about 60 and 950 ° C., a hexane type gasoline boiling between approximately 63 and 6 ° C., a gasoline. type F boiling between about 100 and 1600C and
generally containing 10 to 20% aromatic hydrocarbons,
example 15% (by volume), - a type of essence "white spirit" boiling between about 150 and
25O0C and generally containing 14 to 22% of hydrocarbons
aromatics, for example 17%, by volume, - any hydrocarbon cut or not, equivalent to gasoline
preceding.

The additive or the additives according to the invention can be used in another solvent such as, for example, alcohols (methanol, ethanol, propanol, etc.) or other mineral or organic liquids known to dissolve aldehydes, ketones, ethers, alcohols, polyalcohols, acids and polyacids which can be used according to the present invention.

Among the preferred additives include acetal acetone, diketone, acetonyl acetone, lactic acid and citric acid.

The role of the additive used is to be able to increase, during the first part of the second stage, the degree of reduction of the metal oxides, to reduce these oxides much more quickly, thus favoring the kinetics of oxygen replacement. by sulfur and further promote the dispersion of metals in the catalyst.

As a result, the start of the actual refining or hydroconversion reactions will be accelerated.

EXAMPLES
In Examples 1 to 3 which follow, the effect of the adopted catalyst regeneration method will be studied for hydrorefining or hydrotreating of a hydrocarbon fraction.

p p représentant la somme des titres molaires des produits de conversion du toluène (méthylcyclohexane, éthylcyclopentane et les diméthylcyclopentanes) et 2 T représentant la somme # p + titre de toluène résiduel.The cut proposed for hydrorefining is a model load containing by weight
20% toluene
2% thiophene
78 X cyclohexane
The operating conditions are as follows
Temperature: 3500C
Total pressure: 60 bar
VVH: 2
H / HC 350 lth
Duration of treatment: 48 hours
Catalyst volume involved: 40 cc in the 3 examples 1
to 3 in order to determine the route giving the best
performances
The analysis of the effluents is carried out by gas phase chromatography. The hydrogenation ("A") activity of the toluene and the isomerization ("I") activity of the cyclohexane to methylcyclopentane will be measured in each test.
A = Log 1 lX (natural logarithm) where X is the conversion rate of toluene, i.e.

pp representing the sum of the molar titers of the toluene conversion products (methylcyclohexane, ethylcyclopentane and dimethylcyclopentanes) and 2 T representing the sum # p + residual toluene titer.

X is between 0 and 1, X being 1 for a 100% conversion of toluene.

I = 100 x molar title of methylcyclopentane
Methylcyclopentane molar title
+ residual molar ratio of cyclohexane (the activity in isomerization I makes it possible to measure the acidity of the catalyst).

The catalyst used is a commercial catalyst of the company
Procatalyse HR 346 containing by weight 3% nickel oxide NiO and 14% MoO3 molybdenum oxide, these active metal compounds being deposited on an alumina
Example 1: (comparative)
Before starting the hydrorefining, the catalyst is presulfided according to a conventional method, operating as follows
The catalyst, whose active metals are in the form of their NiO and MoO 3 oxides, is charged to the reactor.

The unit is purged under hydrogen, under cold conditions, and under a pressure of 1 bar (it has been verified that the results would be the same if this step were carried out under a high pressure, 60 bars for example).

The catalyst is heated to 150 ° C. under hydrogen at 1 bar (or 60 bar).

The reactor inlet, whose temperature is 1500 ° C. (at 60 bar pressure), is injected with a sulphurization charge containing by weight
20% toluene
2% dimethyldisulphide
78% cyclohexane
Dimethyldisulphide causes sulfurization of nickel and molybdenum oxides. The operating conditions for sulphurisation are as follows
VVH 2
H2 / HC: 350 l / h
The temperature is increased to 2800C and the sulfurization is continued for 2 hours, then the temperature is raised to 3200C for two hours and finally the temperature is raised to 3500C for a further two hours. The sulphurization of the catalyst being carried out, the charge is then substituted for the sulphurization charge to be hydrorefined and the hydrorefining of this charge is carried out under the operating conditions given above.

Results
A = 0.79
I = 0.29
Example 2 (comparative)
In this example, the catalyst is sulphurated by operating according to the method of European Patent Application No. 84-400234, in two stages.
First stage
For the presulphurization of the catalyst, TPS 37, manufactured by Elf Aquitaine and containing about 37% by weight of sulfur, is used (the formula was given in the general part of this patent application); in order for all of the polysulfide to be adsorbed, a volume of reagent (polysulfide + polysulfide solvent) equal to the impregnation volume of the treated catalyst feed must be used. It is the knowledge of this total pore volume, or impregnation volume, which determines the amount of solvent to be used. For the purposes of this test, this volume, per 100 g of catalyst, is 45 ml on average ( of which 60% solvent and 40% polysulfide). The solvent used is a white spirit (boiling point between 150 and 250 ° C.).

The sulfur stoichiometry necessary to sulphurize all the oxides (NiO, MoO3) is used, ie 7.1% S. The dry impregnation of the catalyst is then carried out, followed by evaporation under 10 mm of mercury or under inert gas stream.

Second step
The catalyst whose metals are in the form of oxides and containing sulfur in its porosity, is introduced into the reactor. The reactor is purged of air and placed in a cold hydrogen atmosphere, under 1 bar (the subsequent results are not changed if the pressure adopted was higher, 60 bar for example). The catalyst impregnated with polysulfide is heated under hydrogen at 1500 ° C. and the temperature is maintained at 1500 ° C. for 2 hours. The catalyst becomes black, this being due to the formation of metal sulfides. Analysis of the TPS sulfided catalyst 37 gives a sulfur value of 7.4% S (weight) and a carbon value of 2% (weight).

Hydrorefining test
The pressure in the reactor is raised to 60 bars and the temperature is raised continuously to 35 ° C.

Results
A = 0.81
I = 0.40
Example 3 (according to the invention)
The first step is identical to the first step of Example 2.

Second Step 1) First part of the second step
The catalyst is introduced into the reactor. We purge cold to chase the air. The reactor is placed in a nitrogen atmosphere under a pressure of one bar (the same results would be obtained under a higher pressure, for example 60 bars).

The catalyst is heated for two hours.

To illustrate the invention, four separate tests are carried out, each of them being carried out at a different temperature.

A T1 test is performed at 1500C
A T2 test is performed at 1000C
A T3 test is performed at 750C
A T4 test is carried out at 275 C
In each test, the catalyst becomes black, the oxides being transformed into sulphides. At the end of each test, the catalyst contains 7.1% sulfur (weight). The carbon content (weight) is 3% in the T1 and T4 tests, 1% in the T2 test and 3.5% in the test
T3.

2) Second part of the second stage and Hydrifice tests
The reactor is placed under a hydrogen atmosphere, cold. The pressure is raised to 60 bars and the temperature to 15O0C.

The charge is injected as in the two preceding examples, then the temperature is raised to 300 ° C. for 1 hour and then to 350 ° C. for the test.

By way of illustration, the results are given in the following table using, to carry out the first part of the first step, three different temperatures, namely 150 C (T1 test), 100 C (T2 test), and 275 C (T4 test). ) and 750C (Test T3).

<Tb>

<SEP> I <SEP> I <SEP> I <SEP> I <SEP> I
<tb> I <SEP> Temperature <SEP> (C) <SEP><SEP> 150 <SEP> l <SEP> 100 <SEP> 1 <SEP> 275 <SEP> 1 <SEP> 75 <SEP> I <September>
<tb> A <SEP> 0.82 <SEP> 0.85 <SEP> 0.75 <SEP> 0.68 <SEP>
<tb> I <SEP> I <SEP> ~~~~ <SEP> I <SEP> ~~ <SEP> ~~ <SEP> I <SEP> ~~~~ <SEP> I <SEP> ~~~ ~ <SEP> I <SEP>
<tb> J <SEP> I <SEP> I <SEP> I <SEP> I
<tb> Ii <SEP> J <SEP> 0.74 <SEP> I <SEP> 1.2 <SEP> I <SEP> 0.74 <SEP> 1 <SEP> 0.55
<Tb>
Note that we verified that the results are the same if the first part of the second stage is performed on the site of presulfuration. This means that the transport of the catalyst and its handling in the air did not cause any damage for this catalyst.

EXAMPLE 4
When the sulfurized catalyst according to the invention is intended for use in a refining reaction whose temperature is below 2750 ° C. (for example a reforming feed pretreatment), it is therefore appropriate, in accordance with the invention, for the catalyst to be the second part of the second stage, first of all worn for at least one hour at least 2750C, for example one hour at 3500C or 2 hours at 300 C. Indeed, the chemisorption of oxygen allows to note that there is a direct relationship between the rate of sulfurization and the uptake of oxygen (expressed for example in moles of oxygen per gram of catalyst). Thus, to study the activity of the catalyst of Example 3, subjected to prior to the first part of the second step, for 2 hours at 1500C (under the conditions of Example 3), this catalyst is subjected in a chemisorption cell at various temperatures under an argon atmosphere for one hour. After each manipulation, the oxygen uptake is measured.

<Tb>

<SEP> measurement of <SEP> adsorp- <SEP> J <SEP>
<tb>SEP> oxygen <SEP> I
<tb> J <SEP> Temperature <SEP> (C) <SEP> unit <SEP> used <SEP>: <SEP> I
<tb> 1 <SEP> | 10 <SEP> 4 <SEP> mole <SEP> oxygen
<tb> by <SEP> g <SEP> of <SEP> Catalyst
<tb> I <SEP> 150 <SEP> 1 <SEP> 0
<tb> 200 <SEP> 1 <SEP> 4 <SEP> 0.02 <SEP> J <SEP>
<tb> I <SEP> 250 <SEP> 1 <SEP>:;<SEP><SEP> 0.01 <SEP> i <SEP>
<tb> 275 <SEP> i <SEP> 0.5 <SEP> J <SEP>
<tb> I <SEP> 300 <SEP> 1 <SEP> 1 <SEP> J <SEP>
<tb> 350 <SEP> 1 <SEP> 1.8 <SEP> J <SEP>
<tb> 400 <SEP> 1 <SEP> 1.8 <SEP> J
<Tb>
This table shows that the activity of the catalyst only develops at about 2750C. If the catalyst does not reach this temperature, it remains inert with respect to oxygen; therefore in return; it remains manipulable in the air, so transportable as the second part of the second stage is not done.

Claims (10)

1. - Process for the two-stage treatment of a new or regenerated catalyst containing (a) a support based on at least one oxide of a metal or a metalloid and (b) at least one active metal, a process in which, in a first step carried out "ex situ" between 0 and 500C approximately and in the absence of hydrogen, the catalyst is treated with at least one sulphurizing agent so as to incorporate partially or totally this agent in the porosity of the catalyst, the sulfurizing agent being a polysulfide of the general formula R - 5 (n) - R 'where n is an integer from 3 to 20 and where R' represents a hydrogen atom or another radical identical or different radical R, these two radicals each representing an organic radical containing 1 to 150 carbon atoms per molecule, these radicals being selected from the group consisting of alkyl radicals that is to say saturated or unsaturated linear or branched or naphthenic type, the r aryl radicals, alkylaryl radicals and arylalkyl radicals, said sulfurizing agent being used in solution in a solvent, the catalyst then being optionally dried, in which process, in a second step, the catalyst obtained in the first step is then treated with a catalyst. characterized in that (a) the catalyst is treated, in the absence of hydrogen and in the presence of an inert gas, for about 1 to 3 hours, "in situ" or "ex situ", at a temperature of between 75 and 2750 ° C., at a pressure of between approximately 0.5 and 70 bars, the catalyst being optionally dried at this stage, (b) this catalyst is then treated for approximately at least one hour at a temperature of at least 2750 ° C. . 2. - The method of claim 1 wherein during said first portion of the second step, the temperature is between 85 and 26O0C, the temperature of said second portion of the second step being between 300 and 4000C. 3. - Method according to one of claims 1 and 2 wherein the second part of said second step is performed "in situ". 4. Method according to one of claims 1 and 2 wherein the second part of said second step is performed "ex situ". 5. - Method according to one of claims 3 and 4 wherein said first part of said second step is performed "in situ". 6. Method according to one of claims 3 and 4 wherein said first part of the first step is performed "ex situ". 7. - Method according to one of claims 1 to 6 applied either to the treatment of a new catalyst, prior to its use, or applied to the treatment of a catalyst, prior to its use, said catalyst having just been subjected to off-site regeneration. 8. - Method according to one of claims 1 to 7, wherein the second part of the second step is carried out in the presence of hydrogen. 9. - Method according to one of claims 1 to 8, wherein in the formula R - S (n) - R ', n is an integer between 4 to 8, R and R' each containing 10 to 60 atoms carbon per molecule. 10. - Method according to one of claims 1 to 9 characterized in that, in the first step, one operates in the presence of 0.4 to 8% by weight relative to the weight of polysulfide of at least one additive chosen in the group consisting of aldehydes containing 4 to 14 carbon atoms per molecule, ketones or polyketones containing 3 to 18 carbon atoms per molecule, ethers containing 5 to 14 carbon atoms per molecule, alcohols or polyalcohols containing 5 to 14 carbon atoms per molecule, at 14 carbon atoms per molecule and organic acids or polyacids containing 3 to 14 carbon atoms per molecule.