Sophisticated process of reactivation applicable to catalysts of hydrogenation.

PATENT AS AFRICAN AND MALAGASY

INDUSTRIAL PROPERTY

P. 887

in Yaounde (Cameroon " International Patent Classification: 01 no. 03354 C.

O A>M-I-P

Request to 16 hr 45 min 25 October 1966

to IOAM.P.I. (G.P. no. 52,637) called by the business:

French Institute of petroleum, fuels and lubricants, residing in France

15 December 1970 delivered

Publishes the ballot official n " 5 of 1970

Priority: Patent application filed in France under the no. 38,843 17 November 1965 on behalf of the applicant.

Improved method of reactivating applicable to hydrogenation catalysts.

The present invention provides an improved method of a fast -

tivation applicable to catalyaaure containing at hand a group VIII metal, such as for example cobalt, platinum, palladium or nickel, dépoeé supported on a tops which have lost at least of their activity as a result of their utilisationf^{the n} ii ' selective hydrogenation of highly unsaturated compounds. EEC catalysts can also contain elements hydrogénanta complementary, i.e. compounds of the groupB VI as e.g. to dB of molybdenum oxides or DB tungsten, or elements neutralizing commB for example, 1b lime, the barytB, the oxydB of poteesiumBodium or oxide.

By compounds highly ineaturés, is meant acetylenic hydrocarbons and diethylenic conjugates, cyclic or acyclic, . convertible by monoethylenic hydrocarbon-selective hydrogenation, ain6i 1 ℮ β that hydrocarbons alkenylsromatic convertible by selective hydrogenation

alkylaromatiquee to hydrocarbons.

These hydrocarbons can be subjected to the selective hydrogenation either as individuals chemically defined, either as a mixture with one another or with other hydrocarbons substantially inert with respect to this form of hydrogenation, especially saturated hydrocarbons (cyclic or acyclic), (cyclic or acyclic) monoethylenic, aromatic or alkylaromatic. It is the case, for example, moieties D'hydrocarbons from pyrolysis or dehydrogenation operations, especially the cracking or of the steam-to-fluid substance. The highly unsaturated hydrocarbons contain at least 2 carbon atoms per molecule, and can be up to 30 carbon atoms, without upper limit. A case of particular interest is that of hydrocarbons of 3 to 15 carbon atoms.

The selective hydrogenation defined above using any one of the aforementioned catalysts at a temperature generally between 0. and 250^S C., and preferably between 100 and 190² C..

After a period of use more or less long, these catalysts lose a part at least of their activity. The reason the n¹ in is not well known, but the job seekers showed that this deactivation came at least in part of a material depot gum or polymeric and also, the these échéent, a poisoning too pushed by the impurities of the load, particularly sulfur impurities.

This désactivatidn is therefore, of a nature different from that observed with the catalysts used at higher temperatures, for example in the operations of hydrocracking, hydrorefining, reforming or even single hydrogenation saturated.

The regeneration proper can be made in a known manner by burning carbonaceous materials, gums and/or-polymers accumulated ies catalyst in use "' the danè ." æéactionsudifeÿdrogé haha.tion. selective however, for these catalysts, the method is delicate and can rarely restore levels of initial activity and selectivity.

The reactivation is least abrupt because not using oxidizing gas. It can be performed, e.g., by contacting hydrogen with the catalyst, at a temperature too high, so as to decompose and remove the polymerized products clogging the catalyst while reducing the oxidized or sulfurized weakly active compounds to the corresponding metal most active. In fact, it has been found that this method was also not sufficient, in particular to restore fully the activity of a selective hydrogenation catalyst.

The present inyention provides a novel method of reactivation in previous disadvantages are greatly reduced if not entirely eliminated.

In this method, the deactivated catalyst is first processed by at least one stable hydrocarbon, liquid state, at a temperature less than 200 °c, for example between 50 and 150 °c, followed by hydrogen at a temperature of between 200 and 500 °c, preferably between 550 and 450 °c.

As stable hydrocarbon, e.g. preferred monoethylenic unsaturation or a saturated hydrocarbon (cyclic or acyclic), or an aromatic hydrocarbon or alkylaromatic (including cycloalkylaromatic), provided it is in the liquid. treatment condition.

These hydrocarbons usually contain 3 to DFEs 16 carbon atoms, preferably 6 to 10.

As specific examples, details should include: a propane, n-butane and ., iéopentane, neopentane, n-heptane derivatives ., octane, nn.dod écane, nn.hexad écane, the cyclohexane, methylcyclohexane, decahydronaphthalene, butene-2, octene and 1, cyclohexene, benzene, toluene, xylenes, ethylbenzene, methyl-1 naphthalene. Mixtures of hydrocarbons may also be used, e.g. in the form of an aromatic fraction or a gasoline not containing gums or labile compounds such as diolefins, acetylenic compounds or alkenylbenzene. The varieties of reforming or direct distillation are particularly recommended. The presence of monoolefins aliphatic or cycloaliphatic is not disturbing "

The preferred temperature of treatment by stable hydrocarbons and 50 is between 150 °c.

The pressure is indifferent provided it is sufficient to maintain a liquid phase hydrocarbon steady. An overpressure may, if necessary, be ascertained with hydrogen or an inert gas.

In general the total absolute pressure will be comprised between 0.5 and 200 atmospheres. In case of using a gasoline fraction, for example, the total pressure will be advantageously between 5 and 30 kg/centimeters.

It is carried out preferably by circulating the hydrocarbons through a bed of deactivated catalyst, e.g. at a rate of 0.5 to 200 (preferably from 1 to 10) volumes of liquid hydrocarbons per volume of catalyst per hour.

The treatment time is usually higher

to 15 minutes and preferably between 1 and 24 hours.

There is usually a weight loss of the deactivated catalyst, corresponding to dissolution of impurities. Another alternative is to follow the operation by metering gums or sulfur compounds in the hydrocarbons from processing.

For this purpose can be used respectively the methods of ASTM no.'d 38 - 6 ΐ ΐ T and D 1266.

The treatment by the hydrocarbons is continued, preferably, butantetraccarboxylic ' that the liquid phase effluent does more than gums or sulfur compounds removed at catalyst "

The subsequent treatment with hydrogen is performed Bene -

tageusement under an absolute pressure of 1 to 200 (preferably 2 to 30)

2

kg./ cm a hourly throughput of hydrogen gas of 5 to 5000 (preferably 50 to 500) liters (under normal conditions of temperature and pressure) per liter of catalyst "

Hydrogen can be used in the pure state or as a mixture with inert gas, such as refinery gas. Preferred toto toutefoir have a hydrogen content greater than 70 %.

The following examples, non-limiting, illustrate the invention:

EXAMPLE 1

This example describes the reactivating a catalyst compound

nickel on alumina, which had been used in the reaction of selective hydrogenation of a shaped charge of:

isoprene: about 10 % (molar #)

benzene: about 90#

sulfur: 100 ppm (about 90 ppm sulfur thiophene

10 ppm sulfur and mercaptans).

The catalyst had the following initial composition:

Alfin 0, . 86.6 %

1 CAD %

The NiO #12.4

After use, the deactivated catalyst had a weight of 10 % higher than its initial weight.

Passed over the used catalyst, under a pressure

2 o.

of 28 kg/cm., temperature θ C. 8, a benzene stream liquid at a space velocity of two volumes per volume of catalyst per hour, until there is no more polymerized product in the liquid effluent, thereby requiring about 3 hours. The injection is stopped this charge and Supplying then hydrogen under a pressure of 5 kg/cm apart, at a rate of 200 to 250 liters time per liter of catalyst and a temperature of 400 °c " this takes about 3 hours.

Any nickel is then reduced to the metallic state.

The reactivated catalyst is used to treat the same charge under the following conditions (with an identical initial conditions):

Hg=40 bar pressure

Ratio Hg/load=250 liters/liter liquid

Temperature=100 °c

Hourly throughput (liquid): 2 volume/volume of catalyst/hour.

The table I according summarizes the performance of the reactivated catalyst according to the invention compared to those obtained with the fresh catalyst, the deactivated catalyst or with the same reactivated catalyst similarly with hydrogen but omitting the treatment by benzene.

TABLE I

* a prolongation of the duration of the treatment with hydrogen does not improves this cipher.

EXAMPLE 2

This example relates to the selective hydrogenation of a gasoline fraction of eraquage water vapor to remove the highly unstable such as conjugated di alkenylaromatic and, for example, confer gums.

This gasoline fraction had the following characteristics:

Distilling with ASTM: OA - 20t °C

Density (grams/platform of the vehicle to 20 °c): 0,765

Sulfur: 5 FIPD by weight.

It is performed under the following conditions:

T * 130 C. pressure hg=28 bar

To Hg/liquid charge ratios=250 liters/liter

Hourly throughput (liquid) 2=volume/volume of catalyst/hour.

The table II summarizes the results obtained avecavec.le fresh catalyst, spent catalyst (2,000 hours of travel) and the catalyst, reactivated in the same manner as the one described in example I in replacing however benzene by a gasoline fraction depentanized does - tale

5 olvement nor unstable compounds, nor gums, and whose characteristics are the following:

10

The composition: aromatic

+ Paraffinic oycloparaffinic

Distilling with ASTM: initial point

End point

Gums current before washing

1' to heptane, in mg/100 em-^

: 69 % (amount)

: 31 %

: 60 °C

: 180 °C

: 0 TABLE II

•remark : The various analyses of the product are performed on the effluent from the reactor directly and not after distillation.

The mesùres indicated are performed according to ASTM standards known. The index of maleic anhydride is measured by standard UOF (UPO méthode 526, 58). The bromine number measures the amount of hydrocarbons in the mass are ethylenic. The index of maleic anhydride is a measure of the content of unstable products, it is to say mainly the diolé ' fine conjugated and styrenes.

See in table II that the spent catalyst which converts more than 10 does 5k % unstable materials (this transformation rate is measured by the decrease in established May calculated to the VAM load) fully recovers its initial activity by the method of reactivating advocated in this patent.

EXAMPLE 5

•s in this example, compared with various methods for reactivation. The catalysts treated are of the same type as that of the example 1 while the filler has the mimics characteristics as that of the example 2. The first step of reactivation is accomplished by means of the gasoline fraction depentanized described in the example above. On it 20 telling by the quality of the gasoline and the hydrogen treatment is performed as in example 2. The results obtained are assembled in Table III.

In this table, the catalyst activity is measured by the conversion conjugated diolefins, expressed as follows:

Conversion of diolefins in % =^ Y° .1.^I X - x 100

where MAVo represents the maleic anhydride of the load and the VAM EF into the effluent.

If it is determined in this table that:

1. The reactivation by simple processing to the traditional gasoline fraction.

2. The reactivation by simple hydrogen treat only allows

not restore catalyst activity.

3 * Both stages of the reactivation must be made following the order indicated in the present invention.

EXAMPLE 4

Selective hydrogenation is carried out with a

density of the gasoline (the d * ^) equal to O, 76, vividly colored, index

bromine 72, and index of maleic anhydride equal to 73"

The catalyst is palladium.

The hydrogenation is carried out at 50 °c under 50 kg/cm.²

with a feed flow rate liquid per hour and per liter of catalyst equal to 4. The ratio Hg gas/liquid hydrocarbon is of 20 liters per liter.

After use when the catalyst is désac -

tivé, is regenerated as stated in example 1; however the hydrogenation temperature is 210 °c final (instead of 400 °cj.

Performances by the catalyst are

the following: