DE3590575T1 - Rejuvenation of a deactivated catalyst - Google Patents

Description

PCT / US85 / 02218

Rejuvenation of a Deactivated Catalyst Background of the Invention

The present invention relates to a method for rejuvenating a zeolite catalyst.

Catalytic reforming is a well known method, Jm which is used to increase the octane number to a naphtha for gasoline. The reactions that take place during reforming are as follows: dehydrocyclization of acyclic hydrocarbons, dehydrogenation of cyclohexanes, dehydroisomerization of alkylcyclopentanes, isomerization of paraffins, dealkylation of alkylbenzenes and hydrocracking of paraffins. The hydrocracking reaction should be suppressed because that reaction lowers the yield of hydrocarbons and reduces ^ O 3i _e yield of liquid products.

Reforming catalysts must be used for dehydrocyclization be selective to produce high yields of liquid product and low yields of light gases. This

* ° Catalysts should have good activity so that low temperatures can be maintained in the reformer. They should also have good stability, like that that they maintain high activity and high selectivity for dehydrocyclization for a long period of time. Furthermore, they should be regenerable in such a way that they can be regenerated without loss of efficiency be able.

Most reforming catalysts contain platinum an alumina support, but other catalysts such as large pore zeolites have also been proposed. This large-pore zeolites have pores that are large enough to

so that the hydrocarbons in the gasoline boiling range pass through. However, catalysts based on these zeolite supports have not been commercially successful.

More recently, a new catalyst has been developed that is composed of a large-pore zeolite, a Group VIII metal and an alkaline earth metal. This catalyst has a very high selectivity for dehydrocyclization however difficult to regenerate.

Summary of the invention

._ The catalyst according to the invention is based on the finding 15th

that a catalyst can be rejuvenated by contacting the catalyst with an aqueous medium selected from the group consisting of water, an aqueous solution and saturated water vapor. This rejuvenation process

works in the case of large-pore zeolite catalysts, the Λ U

contain at least one Group VIII metal.

According to a first embodiment, at least 10 ecm of an aqueous medium per ecm of the catalyst is used

_ be and the aqueous medium must be in the liquid 25th

Phase. Preferably at least 500 ecm will be one aqueous medium used per ecm of the catalyst. Before contacting the catalyst with an aqueous Medium it should be exposed to oxidizing conditions,

preferably at a temperature of about 200 ⁰ C to 30

about 450 ⁰ C. After the catalyst with an aqueous

Medium has been contacted, it should be exposed to reducing conditions, preferably in the presence of hydrogen at a temperature of about 200 ° C to about 700 ⁰ C. The stages of oxidation of the catalyst, of 35

Contacting the catalyst with an aqueous medium

and the reduction of the catalyst can if necessary repeated until the catalyst has been tapered to the desired level.

A basic solution (i.e. with a pH greater than 7)

can be used instead of water or saturated water vapor. In this embodiment, the catalyst is contacted with a basic solution at a temperature of -, Q approximately 70 ^° C. to approximately 80 ^{° C.} The basic solution can be an alkali metal hydroxide solution, such as a potassium hydroxide solution, with a pH of at least 10.

According to a second embodiment, a zeolite catalyst, psator can be tapered and the stability of this catalyst can be improved by contacting the catalyst with an aqueous solution of a metal salt or metal hydroxide, the metal being either an alkali metal or a Is alkaline earth metal.

According to a third embodiment, a zeolite catalyst

Sator can be rejuvenated by washing the catalyst with either a neutral or acidic solution, contacting the washed catalyst with an aqueous solution _oc - a metal salt or a metal hydroxide (the metal is either an alkali metal or an alkaline earth metal), washing the contacted catalyst with a neutral solution and drying the catalyst washed twice. This process is suitable for both sulfur-containing

dirty catalytic converters as well as catalytic converters that are on 30

other way have been deactivated.

In the second and third embodiment, the concentration of the aqueous solution should preferably be 0.1 to 10% by weight

of the metal. A more preferred concentration range 35

varies between 0.1 and 8% by weight of the metal. Preferably

are 2 to 30 ecm of the aqueous solution per gram of the catalyst at each washing stage.

c Preferably, in the second and third embodiment, the metal salt or hydroxide is either a metal halide, a metal nitrate, a metal carbonate, a metal phosphate or a metal hydroxide. The preferred metal salt is a metal hydroxide such as potassium hydroxide.

Preferably, the contacting occurs in the second and third embodiment at a temperature of 25 ° C to 100 ⁰ C (in particular from about 8O ⁰ C), after which the catalyst has been contacted with the aqueous solution containing 10 to

200 ecm of water per gram of the catalyst to remove Ib

excess metal is washed and the washed catalyst is dried. Preferably the catalyst contacted with an oxidizing gas under conditions conducive to oxidation prior to the first washing stage is carried out.

Description of preferred embodiments

In its broadest aspect, the present invention relates to the rejuvenation of a catalyst by contacting the Catalyst with a large amount of an aqueous medium in the liquid phase. This contacting stage is an essential one Element of the invention.

The aqueous medium must be in the liquid phase. If there is no water in the liquid phase, then the shows Contacting stage not the surprising regeneration according to the present invention.

Furthermore, a large amount of the aqueous medium is required. At least 10 ecm of an aqueous medium should be per ecm of the catalyst can be used. Preferably there should be at least 500 cmm of the aqueous medium per ecm of the catalyst be used.

This regeneration method is not only suitable for catalysts contaminated with sulfur, but also for catalysts which have been deactivated in other ways.

A basic solution can be used to contact the sulfur contaminated catalyst at a temperature of about 70 ^° C to about 80 ^{° C.} Preferably the basic solution is an alkali metal hydroxide-15

solution, such as a potassium hydroxide solution, with a pH of at least 10. This embodiment has the advantage that the formation of acidic sites on the catalyst is kept to a minimum.

A saturated water vapor in the liquid phase can be used to contact the sulfur-contaminated catalyst, preferably at a temperature of approximately 120 ^° C. to approximately 180 ^° C. This embodiment has

the advantage that an in situ treatment can be carried out 25th

can without removing or handling the catalyst.

The present invention rejuvenates the catalyst without removal of all the sulfur from the catalyst. Although it is not yet fully understood how by the invention the surprising rejuvenation of sulfur fouled catalysts occurs, according to one theory thereof assume that the washing is the present in the catalyst

Sulfur in a state that is more easily removed from the catalyst 35

remove during the reduction and reforming process

is bar, or converted into a state that does not affect the desired catalytic reactions.

_ The catalyst can be used in oxidizing conditions before b

Contacting the catalyst with an aqueous medium can be exposed. The contacting stage causes a noticeable tapering of the catalyst, while the combination of oxidation stage and contacting stage causes an even more noticeable tapering. The oxidation stage is preferably carried out in the presence of oxygen at a temperature of approximately 200 ^° C. to approximately 450 ^° C. The oxidation stage alone does not rejuvenate the catalyst.

It is believed that the oxidation state makes the sulfur one 15th

changes its water-soluble form and / or weakens the association between platinum and sulfur. This could be done with others Oxidizing agents in addition to oxygen, such as KMnO., CrO-, etc. be effected. This could also be applied to other metal containing catalysts that use sulfur is known to damage the activity.

The catalyst can undergo reducing conditions after contacting the catalyst with an aqueous medium

get abandoned. The reduction stage is preferably carried out 25th

in the presence of hydrogen at a temperature of 200 ^° C. to 700 ^° C. There is no rejuvenation through the reduction stage alone or through a reduction and subsequent oxidation without switching on the water stage.

The effectiveness of this reduction stage can depend on whether the solvent molecules shielding the platinum are removed faster than the sulfur is reduced. In this context it was found that if at

moist hydrogen is used in water treatment, a 35

more stable tapered catalyst is obtained. Other

Reducing agents such as water-soluble hydrazine hydrate, NaBH. or KBH., could also be used for this stage.

The combination of the oxidation level, the soaking level and the reduction stage cause an even more noticeable rejuvenation than the combination of the soaking stage with either only the oxidation stage or only the reduction stage. These three stages can be repeated as long as necessary until the catalyst has been tapered to the desired extent.

A sulfur-contaminated catalyst can be exposed to oxidizing conditions in the presence of oxygen at a temperature of about 200 ⁰ C to about 450 ° C, the oxidized catalyst is saturated with at least 500 ecm of water vapor in the liquid phase per ecm of the catalyst at a temperature of about 120 ⁰ C to about 180 ⁰ C contacted and then the catalyst is exposed to reducing conditions in the presence of hydrogen at a temperature of 200 ⁰ C to about 700 ^{0 C.} These steps are repeated until the catalyst has been tapered to the desired extent.

According to a second embodiment, a large-pored

Zeolite catalyst containing at least one Group VIII metal tapered by contacting the catalyst with an aqueous solution of a salt of a metal, selected selects from the group consisting of an alkali metal and an alkaline earth metal.

An essential stage of this embodiment consists in that the catalyst with an aqueous solution of a salt gc or hydroxide of a metal selected from the group which consists of an alkali metal and an alkaline earth metal,

must be contacted. The metal salt or hydroxide can be: Either a metal halide, a metal nitrate, a metal carbonate, a metal phosphate or a metal hydroxide. Preferably the metal salt or hydroxide consists of potassium hydroxide. Preferably, the catalyst with 2 to 30 cc of aqueous solution per gram of the catalyst at a temperature of 25 ° C to 100 ° C and in particular at a temperature of about 80 ⁰ C contacted. The aqueous solution should have a concentration of 0.1 to 10% by weight of metal, preferably 1 to 8% by weight of metal.

After the catalyst has been contacted with the aqueous solution, the catalyst is mixed with 10 to 200 ecm of water •, c per gram of catalyst washed to remove excess To remove metal, then the washed catalyst is dried.

The sulfur contaminated catalyst can be a type 2Q L zeolite containing 8 to 10 wt% barium and 0.1 to 1.5 wt% platinum, with an inorganic binder selected from the group being provided which consists of silica, alumina, aluminosilicates and clays. This contaminated with sulfur catalyst is ever at a temperature of about 80 ⁰ C and 2 to 30 cc

an aqueous potassium hydroxide solution per gram of catalyst contacted. The aqueous solution has a concentration of 1 to 8% by weight metal. After the catalyst with a Solution has been contacted, he will be 10 to 200 ecm oQ water per gram of catalyst to remove excess Metal washed and then dried.

The catalyst can be with a neutral or acidic solution washed, then with an aqueous solution of an alkali

", - metal salt or an alkaline earth metal salt contacted if

and then washed with a neutral solution and dried

- JtO-

will.

According to a third embodiment, the present

Invention of the rejuvenation of a large-pore zeolite catalyst

tors containing at least one Group VIII metal, by washing the catalyst with a non-basic solution, contacting the washed catalyst with a aqueous solution of a salt of a metal selected from the group consisting of an alkali metal and an alkaline earth metal consists of washing the contacted catalyst with a neutral solution and drying the washed catalyst. This regeneration process is not only suitable for catalysts contaminated with sulfur, but also

for catalysts that have been deactivated in other ways 15

are.

When rejuvenating a catalytic converter contaminated with sulfur the present invention rejuvenates the catalyst,

without removing all of the sulfur from the catalyst. 20th

Before the catalyst has been contacted with the aqueous solution, it becomes either neutral with 10 to 200 ecm Solution or an acidic solution per gram of the catalyst washed.

An essential stage of this embodiment consists in that the catalyst with an aqueous solution of a salt or hydroxide of a metal selected from the group, which consists of an alkali metal and an alkaline earth metal,

must be contacted. The metal salt or hydroxide can either be a metal halide, a metal nitrate, a metal carbonate, be a metal phosphate or a metal hydroxide. Preferably, the catalyst is 2 to 30 ecm one aqueous solution per gram of catalyst at one temperature

of 25 ° C and 100 ⁰ C and in particular at a temperature of approximately 80 ⁰ C contacted.

-vö-

The aqueous solution should have a concentration of 0.1 to 10 wt .-% metal, preferably 0.1 to 8 wt .-% metal,

._ sit,
ο

After the catalyst has been contacted using the aqueous solution, the catalyst with 10 to 200 cc of water per gram of catalyst is washed to remove excess metal, then the washed one is washed Catalyst dried.

Preferably, the catalyst is contacted with an oxidizing gas under conditions that favor oxidation, before the first washing stage is carried out. 15th

According to a preferred method of this embodiment is the deactivated catalyst is a sulfur-contaminated catalyst, which has a type L-zeolite, the 8 to Contains 10 wt .-% barium and 0.1 to 1.5 wt .-% platinum, wherein an inorganic binder is present, which consists of the Is selected from the group consisting of silica, alumina, aluminosilicates, and clays. This one with sulfur contaminated catalyst becomes with an oxidizing gas

contacted under conditions conducive to oxidation, 25

and the catalyst is washed with a neutral solution, and the catalyst at a temperature of about 80 ⁰ C and 2 to 30 cc of an aqueous potassium hydroxide per gram of catalyst will be contacted. The watery

Solution has a concentration of 0.1 to 8% by weight 30th

Alkali or alkaline earth metal. After the catalyst has been contacted with a solution, it is 10 to 200 cc of water per gram of catalyst was washed to remove excess metal and then dried.

A reforming catalyst made by the present invention can be regenerated is a large-pore zeolite that is loaded with one or more dehydration constituents is. The term "large pore zeolite" defines a zeolite with an effective pore diameter of 6-15 Angstrom.

Type L zeolite, zeolite X, zeolite Y and faujasite are presumed -, Q loaned the best large pore zeolites for the measure and own apparent pore sizes on the order of 7 to 9 angstroms. The preferred catalyst is a type L zeolite, which is loaded with one or more dehydrating components.

An alkaline earth metal can be present in the catalyst. This alkaline earth metal can be either barium, strontium, or calcium. The alkaline earth metal may be in the zeolite by synthesis, _one introduced by impregnation or by ion exchange. Barium is preferred over the other alkaline earths because the catalyst obtained has high activity, high selectivity and high stability. The barium should preferably constitute from about 0.1 to about 35 weight percent of the zeolite, and more preferably from about 1 to about 20 weight percent.

The reforming catalysts of the invention are with loaded with one or more metals of group VIII, for example nickel, ruthenium, rhodium, palladium, iridium or platinum.

The preferred Group VIII metal is platinum, which is, and is, more selective to dehydrocyclization is more stable than other Group VIII metals under the reforming reaction conditions. The preferred percentage

_o _ the platinum in the catalyst is between 0.1% and 5%

. AS-

-γί-

and especially between 0.1% and 1.5%.

An inorganic oxide can be used as a carrier

to bind the large-pored zeolite. The wearer can be a natural 5

Liches or synthetically produced inorganic oxide or a combination of inorganic oxides. Preferred Quantities of the inorganic oxides are between 5 and 50% by weight of the catalyst. Typical inorganic oxide supports that

Can be used are silica, 10 alumina

and aluminosilicates.

T Examples

The first embodiment of the present invention becomes explained in more detail by the following examples, which are a particularly advantageous method and particularly preferred compositions show. The examples serve only to illustrate the invention without restricting it.

example 1

A catalyst is made by (1) ion exchange

of a potassium-type L zeolite with such a volume of one 25th

0.17 molar barium nitrate solution, which is sufficient that a

Excess of barium compared to the ion-exchange capacity of the zeolite is present, (2) drying the resulting barium-exchanged type L zeolite catalyst, (3) calcining the catalyst at 590 ⁰ C, (4) impregnation of the 30

Catalyst with 0.8% platinum using tetrammineplatinum (II) nitrate, (5) drying the catalyst, (6) calcining the catalyst at 260 ⁰ C, and (7) reducing the catalyst in hydrogen at 480 ⁰ C to 500 ⁰ C.

-yi-

Example 2

The catalyst from Example 1 is used in a pilot plant for the 5th

Reforming η-hexane, which has been hydrofined to remove sulfur, oxygen and nitrogen has been used. Reforming occurs at 860 ° F, 100 psig, an LHSV (liquid hourly space flow rate) from 17 and 5 H_ / HC. The results after 10 and 20 hours are shown in Table I. emerged.

Example 3

The catalyst of Example 1 is used in a pilot plant

used to reform naphtha used to remove Sulfur, oxygen and nitrogen had been hydrofined and then sulfur compounds have been intentionally added around a 20

Sulfur contaminated catalyst to produce. The reforming takes place at 860 ⁰ F, 100 psig, an LHSV value of 1.5 and 6 H ^ / HC for 3 weeks zur.Erzeugung a sulfided catalyst, whereupon the sulfided catalyst after the

Methods of Example 2 is tested. The results of this 25th

Tests after 10 and 20 hours are shown in Table I.

Example 4

The sulfided catalyst of Example 3 is oxidized in 1 atmosphere with 1% oxygen in nitrogen for half an hour at 400 ^° F, 1 hour at 500 ^° F and 5 hours at 750 ^° F Methods tested. The results of this test after 10 and 20 hours are shown in Table I.

-AS

-j / 4-

Example 5

The sulfided catalyst from Example 3 is with 80 ⁰ C-

Washed water at 2 cc / min for 1 hour, whereupon the Catalyst is tested according to the methods described in Example 2. The results of this test after 10 and 20 hours can be seen from Table I.

Example 6

The sulfided catalyst of Example 3 is oxidized at 1 atmosphere with 1% Sauertstoff in nitrogen for one half hour at 400 ° F, one hour at 500 ⁰ F and 5 Stundden at 750 ⁰ F, then with 100% steam at 212 ° F washed for 3 hours, after which the catalyst is tested according to the methods described in Example 2. The results of this test run out after 10 and 20 hours

Table I.
Λ U

Example 7

The sulfided catalyst of Example 3 is at 1 atmosphere with 1% oxygen in nitrogen for half a 2o

Oxidized hours at 400 ⁰ F, one hour at 500 ⁰ F and 5 hours at 750 ⁰ F and then with 100% steam for 3 hours at 212 ° F washed and then reduced in H "during one and a half hours at 900 ⁰ F, then at 1 atmosphere with

1% oxygen in nitrogen for half an hour 30th

400 ⁰ F, oxidized at 500 ⁰ F one hour and 5 hours at 750 ⁰ F, and then washed with 100% steam at 212 ° F for 3 hours, then the catalyst is tested according to the methods described in Example 2. The results of this test after 10 and 20 hours are based on the 35th

Table I.

. away

Example 8

The sulfided catalyst of Example 3 is oxidized at 1 Atmoshare with 1% oxygen in nitrogen for one half hour at 400 ⁰ F, one hour at 500 ⁰ F and 5 hours at 750 ⁰ F, then with a 100% ethyl steam at 212 washed ° F for 3 hours, then reduced at 900 ⁰ F in H "during one and a half hours, then at 1 atom -. <-> phere with 1% oxygen in nitrogen for one half hour at 400 ⁰ F, one hour at 500 ⁰ F and oxidized for 5 hours at 750 ⁰ F, then washed with 100% steam at 212 ⁰ F for 3 hours, then ^{reduced at 900 0} F in H- for one and a half hours, then at 1 atmosphere with

., _ 1% oxygen in nitrogen for half an hour Ib

oxidized at 400 ° C, one hour at 500 ⁰ F and 5 hours at 750 ⁰ F, then washed with 100% steam at 212 ° F for 3 hours, then the catalyst is tested according to the methods described in Example 2. The results of this test after 10 and 20 hours are shown in Table I.

Table I.

Relative speed constants for

Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8

Conversion of saturated C, compounds during operation

Benzene formation during operation

% Selectivity to. Benzene in operation

10h 20h 10h 20h 10h 20th 1 1 1 1 86 85 0.08 0.09 0.01 0.01 11th 12th 0.21 0.18 0.10 0.09 40 45 0. 19 0.19 0. 10 0.10 45 45 0.71 0.74 0.53 0.56 75 76 0.81 0.80 0.80 0.76 84 81 0.81 0.80 0.80 0.76 84 81

Examples 5, 6, 7 and 8 are examples in accordance with the present invention. They show that washing, either alone or in conjunction with an oxidation that rejuvenates deactivated catalysts.

Example 9

The second embodiment of the present invention will illustrated in more detail by the following examples, which are a particularly preferred method and preferred compositions reproduce. The examples serve only to illustrate the invention without restricting it.

Fresh reforming catalyst is made by

(1) Ion exchange of a potassium type L with such Volume of a 0.17 molar barium nitrate solution which is sufficient to show an excess of barium in comparison to the ion exchange capacity to provide the zeolite,

(2) drying the obtained barium-exchanged type L zeolite catalyst, (3) calcining the catalyst

.iss

59O ° C, (4) impregnation of the catalyst by means of a pore filling impregnation with 0.8% platinum using tetrammine platinum (II) nitrate, (5) drying the catalyst;

_ (6) Calcine the catalyst at 260 ° C and (7) Redub

decorate the catalyst in hydrogen at 480 ⁰ C to 500 ⁰ C.

A feed of η-hexane, which has been subjected to removal of sulfur, oxygen and nitrogen of a hydrofining treatment psig at 920 ⁰ F, 100th, an LHSV of 10 and 5 _H2 / HC with a portion of contacted fresh reforming catalyst. The benzene selectivity and the hexane conversion for this experiment can be seen from FIGS.

A second serving of the fresh reforming catalyst is deactivated by contacting the catalyst with a sulfur-containing light straight run until approximately 200 ppm sulfur is deposited on the catalyst. The DEACTIVATED catalyst is rejuvenated by contacting the catalyst for 2 hours at a temperature of about 80 ⁰ C with an aqueous solution of potassium hydroxide having a concentration of 5 wt .-% metal, 30 of aqueous solution per gram of catalyst ecm present, 10-

repeated washing of the catalyst, which was mixed with the aqueous 25

Solution has been contacted with 20 ecm of water per gram Catalyst (total of 200 ecm washing solution) to remove excess metal and dry the washed Catalyst. A n-hexane feed used for removal

of sulfur, oxygen and nitrogen in a hydrofining 30

Treatment has been subjected to 100 is at 920 ⁰ C, psig, contacted by an LHSV of 10 and 5 H- / HC with the tapered reforming catalyst.

Examples 10 to 23

The third embodiment of the present invention becomes explained in more detail by the following examples, which show a particularly advantageous method and particularly advantageous compositions indicate. These examples illustrate the invention without restricting it.

jQ A type L zeolite reforming catalyst is used with a Treated sulfur-containing hydrocarbon feed, until the catalyst is essentially deactivated. The catalyst is made by (1) extruding the catalyst with 20% by weight of an aluminum oxide

, c Inorganic oxide binder in the form of a 1/16 inch extrudate., (2) Ion exchange of a potassium-type zeolite with a volume of a 0.3 molar barium nitrate solution that is sufficient to that there is an excess of barium compared to the ion exchange capacity of the zeolite, (3) drying the

2Q resulting barium-exchanged type L zeolite, (4) calcining the catalyst at 590 ⁰ C, (5) impregnating the catalyst with 0.8% platinum, based on the weight of the L-zeolite using tetrammineplatinum (II) nitrate (6) drying the catalyst (7) calcining the catalyst at 260 ⁰ C in air or 50% sodium water vapor (8) extruding the catalyst with 20 wt .-% of a group consisting of alumina in the form of inorganic Oxidbindungsmittels 1/16 inch extrudate, and (9) reducing the catalyst in hydrogen at 480 ^° C. to 500 ^° C. The catalyst is method

"Q been deactivated that it has been under mild reforming conditions (100 psig, 870 ⁰ F, 2 H ₂ / HC, LHSV 1.5) containing sulfur with a naphtha feedstock (1.5 ppm dimethyl disulfide) used in operation is. This catalyst is then used in a variety of regeneration processes

oc driving and then tested according to the following test.

> 9

Regeneration test

0.356 grams of catalyst, which has a particle size of

24 to 80 mesh are sifted into a tube-5

shaped reactor. A small surface area alpha alumina is placed above and below the catalyst. The catalyst is at 400 ⁰ F in hydrogen, the with 500 ccm / min. flows for half an hour,

then at 880 ^° F in hydrogen for 10 minutes and then 10

treated at 92O ⁰ F in hydrogen for 1 hour. After 1 hour at 920 ^° C., the hydrogen flow is increased to 60 ccm / min. and the pressure increased from atmospheric to 100 psig. At this time, η-hexane is used in an amount of

3 cc / hour introduced. The start and end values are after 15th

about 2 hours and 18 hours after inserting the

n-hexane loading determined. The conversion (conversion), the selectivity for the dehydrocyclization (Sci.) And the Yields of aromatics in the product as mole percent of the feed (mole percent) are calculated at these points in time. 20th

Example 10

The catalyst in this example is not treated by any regeneration process. 25th

Example 11

The catalyst of this example is placed in a quartz reactor tube

put in an oven, then 1% oxygen in stick-30

substance passed over the catalyst in an amount of 2 ccm / g catalyst / min. The catalyst is ^{treated at 600 °} F. for 1 hour, then the catalyst is treated at 780 ^° F. for 5 hours. The flow of oxygen is then stopped and the catalyst is turned on to the room

temperature cooled. Then the catalyst is charged three times

-ge, namely: (1) with a 10-fold excess deionized water for 30 minutes at 165 ° C, (2)

cooled and (3) filtered. Then the catalyst in 5

Getrockent air during 2 hours at 250 ⁰ F and then treated in flowing air at 500 ⁰ F for 2 hours.

Example 12

The catalyst in this example is placed in a quartz reactor tube in an oven, then 1% oxygen in nitrogen is passed over the catalyst at a rate of 2 cc / g catalyst / min. The catalyst is ^{treated at 600 0} F for 1 hour, then the catalyst is

treated at 780 ° F for 5 hours. The flow the oxygen is then stopped and the catalyst cooled to room temperature. Then the catalyst treated three times as follows: (1) for 30 minutes at 165 ° C with a 10-fold excess of an aqueous chlorine

hydrogen solution with a pH of 3, (2) cooling and

(3) filter. The catalyst is then ^{dried in air at 250 °} C. for 2 hours and ^{treated in flowing air at 500 °} C. for 2 hours.

Example 13

The catalyst of this example is placed in a quartz reactor tube in an oven, then 1% oxygen in nitrogen over the catalyst at one rate

of 2 cc / g catalyst / min. The catalyst is treated at 600 ⁰ F for 1 hour, then the catalyst at 80 7 ⁰ F is treated for 5 hours. The flow of oxygen is then stopped and the catalyst is cooled to room temperature. The catalyst is then heated to 176 ° C. for 2 hours and occasionally in the presence

-24-

stirred a 20-fold excess of an aqueous solution of 4 wt .-% KOH, then cooled and filtered. The catalyst is then treated nine times as follows: (1) mixed with a 10-fold excess of water at room temperature for 1 minute, (2) allowed to settle for 3 minutes, and (3) filtered. At this point the pH of the draining water is 7.5. The catalyst is then ^{dried in air at 250 °} C. for 20 hours and ^{treated in flowing air at 500 °} C. for 2 hours.

Table II shows the effect of the regeneration methods of Examples 10 to 13. This table shows that the regeneration with a previous oxidation and subsequent contact with water or an aqueous one Solution and subsequent drying and calcining a significant regeneration of the deactivated catalyst conditional. Of these 4 examples, the example (KOH wash) gives the best results.

effect table II Mol% with water end Mol% of regeneration 2.15
36.09
9.85
35.63 May be. 2.45
11/25
7.67
32.90 Around At first- Around 62.29
87.25
73.
90.64 example 4.96
42.07
14.58
40.72 May be. 3.93
28.78
10.58
36.29 10
11th
12th
13th 43.27
85.79
68.
87.49

Example 14

The catalyst of this example is placed in a quartz reactor tube in an oven and 1% oxygen in nitrogen is passed over the catalyst at a rate of 2 cc / g catalyst / min. The catalyst is treated at 600 ° F for 1 hour, then the catalyst at 78o F ⁰ is treated for 5 hours. The flow of oxygen

IQ is then stopped and the catalyst is cooled to room temperature. Then the catalyst was, for three times: (1) treatment with a 10-fold excess of deionized water for 30 minutes at 165 ⁰ C, (2) cooling and (3) filtered. Then the catalyst is three-

Treated 1 ^ 5 times as follows: (1) heating to 135 ° C for 1 hour in the presence of a 10-fold excess of an aqueous solution of 0, IN KOH, (2) cooling and (3) filtering. The catalyst is then washed with a 10-fold excess of deionized water at 140 ⁰ F for 1 hour,

2Q then cooled and filtered. Then, the catalyst in air at 250 ⁰ F for 2 hours, is dried and treated in flowing air at 500 ⁰ C for 5 hours.

Table III shows the improvement that is achievable, ok when the catalyst with a neutral solution before a KOH washing is treated. Out. the table is clearly too see that washing the catalyst with a neutral wash solution prior to the KOH wash gives better results than when there is no neutral washing.

Table III

Effect of the neutral wash before the KOH wash

τ-, · · ■, τ-, start- .., _o ,, end- "," example ums. = -: - ^ - Mon 1-% turnover = - mol% at . bsι

₁₃ 40.72 87.49 35.63 36.29 90.64 3.2.90

14 56.73 93.13 52.83 54.15 95.10 51.49

example

_ ■ The catalyst of this example is heated to 176 ° F during b

Heated for 2 hours and occasionally stirred in the presence of a 20-fold excess of an aqueous solution of 4% by weight KOH, then cooled and filtered. The catalyst is then treated nine times as follows: (1) mixed with a 10-fold excess of water at room temperature for 1 minute, (2) allowed to sit for 3 minutes and (3) filtered. At this point the pH of the draining water is 7.5. Then the catalyst is ^{dried in air at 250 0} F for 20 hours and in flowing

Treated air at 500 ⁰ F for 2 hours. 15th

example

The catalyst of this example is treated three times as follows: (1) Treatment for 30 minutes at 165 ° F in 20

a 10-fold excess of an aqueous solution of hydrogen chloride with a pH of 3, (2) cool and filter. Then the catalyst is treated three times as follows: (1) Mix with a 10-fold excess of a solution

of O, 1N KOH, (2) treatment with the KOH solution during 25th

1 hour at 135 ^° F, (3) cooling and (4) filtering. Then the catalyst is treated with a 10-fold excess of deionized water at 135 ⁰ F, cooled and filtered. Then the catalyst is in air at 250 ^° F

dried for 2 hours and in flowing air at 30

Treated SOO ⁰ F for 2 hours.

' Example

The catalyst of this example is placed in a quartz reactor tube 35

placed in an oven then turns 1% oxygen into nitrogen

-34-

passed over the catalyst in an amount of 2 ccm / g catalyst / min. The catalyst is treated at 600 ⁰ F for 1 hour, then the catalyst at 780 ° F while c is treated for 5 hours. The flow of oxygen is then stopped and the catalyst is cooled to room temperature. Then the catalyst was, for three times: (1) treatment with a 10-fold excess of deionized water for 30 minutes at 165 ⁰ F, (2) cooling and (3) filtered. Then the catalyst was, for three times: (1) treatment for 1 hour at 135 ⁰ F in a 10-fold excess of a solution of 0.1N sodium carbonate, (2) cooling and (3) filtered. Then the catalyst is treated three times as follows: (1) Treatment

. _c for 1 hour at 135 ° F in a 10-fold excess Ib

of deionized water, (2) cooling, and (3) filtering. Then, the catalyst in air at 250 ⁰ F is getrockent for 2 Stundden and treated in störmender air at 500 ⁰ F for 2 hours.

Example 18

The catalyst of this example is placed in a quartz reactor tube in an oven, then 1% oxygen is added in

Nitrogen over the catalyst at a rate of 2b

of 2 cc / g catalyst / min. The catalyst is ^{treated at 600 °} F. for 1 hour, then the catalyst is treated at 780 ^° F. for 5 hours. The flow of oxygen is then stopped and the catalyst

_n temperature cooled. Then the catalyst turns 30 three times

treated as follows: (1) Treated for 30 minutes at 165 ° F with a 10-fold excess of an aqueous solution of pH 3 hydrogen chloride, (2) cooling and (3) filtering. Then the catalyst is used three times as follows

_ocr treated: (1) Treated for 1 hour at 135 ° F at 35

a 7-fold excess of a solution of 0.1N sodium carbonate, (2) cooling and (3) filtering. Then the catalyst was, for three times: (1) treatment at a temperature of 135 p ⁰ F for 1 hour with a 7-fold excess of deionized water, (2) cooling and (3) filtered. Then, the catalyst in air at 250 ⁰ F for 2 hours, is dried and treated in flowing air at 500 ⁰ C for 2 hours.

Table IV shows the further improvement brought about by a previous treatment with an acidic solution can be achieved. Two pairs of data are shown, the first in in each case treatment with a neutral solution or

P- with no solution at all before treatment with the saline solution and the second in each case involves a first treatment with an acidic solution. The differences between the first pair of data and the second show the advantages of pre-oxidation before the

_n aqueous treatments, especially when the acidic treatment step has been omitted.

Table III

effect one acidic vasification At first- Mol% conversion before the SaIz- washing without pre-oxidation May be. 22.61 8.42
53.13 58.52
Pre-oxidation . 82 * 13
93.48
With end example Around May be. Mol% 15th
16 27.53 /
56.84 65. 45
96.08 5.51
56.23

Start end

Example around May be. Mol% conversion May be. Mol%

47.96 89.29 42.82 41.77 91.84 3R.36

18th

61.92 88.01 54.49 55.66 91.12 50.72

Example 19

The catalyst of this example is maintained at 176 ° F during g heated for 2 hours and occasionally in the presence of a

Stirred 20-fold excess of an aqueous solution of 4 wt .-% KOH, then cooled and filtered. The catalyst is then treated nine times as follows: (1) mixing with a 10-fold excess of water at room temperature for 1 minute, (2) allowing to settle for 3 minutes and (3) filtering. At this point the pH of the draining water is 7.5. The catalyst is then ^{dried in air at 250 °} C. for 20 hours.

, ρ- example 20

The catalyst of this example is placed in a quartz reactor tube in an oven, then 1% oxygen in nitrogen is passed over the catalyst at a rate of 2 cc / g catalyst / min. The catalyst is ^{treated at 600 °} F. for 1 hour, then the catalyst is treated at 780 ^° F. for 5 hours. The flow of oxygen is then stopped and the catalyst is cooled to room temperature. The catalyst is then heated to 176 ° F for 2 hours and occasionally stirred in the presence of a 20-fold excess of an aqueous solution of 4% by weight KOH, then cooled and filtered. The catalyst is then treated nine times as follows: (1) Mixing with a 10-fold excess of water at room temperature

O ₀ temperature for 1 minute, (2) allowing to settle for 3 minutes, and (3) filtering. At this point the pH of the draining water is 7.5. The catalyst is then ^{dried in air at 250 °} C. for 20 hours.

Example 21

The catalyst of this example is used three times as follows

treated: (1) treatment for 30 minutes at 165 ^° F with b

a 10-fold excess of an aqueous solution of hydrogen chloride with a pH of 3, (2) cooling and. (3) filter. The catalyst is then treated three times (1) with an aqueous solution of 0.1N sodium carbonate at 135 ° F for 1 hour, (2) cooled, and (3) filtered. Then the catalyst was, for three times: (1) treatment for 1 hour at 14O ⁰ F with a 10-fold excess of deionized water, (2) cooling and (3) filtered. Then, the catalyst in air at 250 ⁰ F is getrockent for 2 hours and in flowing air at 500 F ⁰ while ^y

Treated for 2 hours.

Table V shows the importance of using a pre-oxidation step. It contains 4 data pairs beginning with and

can be obtained without this stage.
20th

effect Table : Mol% , 69 Around 86 End 67 Mole -% rv 20th , 29 18th 31 May be 29 15th 59 Around 35. , 30 31. 88 82. 90 27 95 example 24.73 the pre-oxidation 49. , 49 49. 66 89 12th 46. 34 19th 39.86 At first- 54. 55. 92 50 72 20th 55. 26 May be. 22nd 91. 21 61.92 83.68 17th 88.53 88.85 88.01 example

The catalyst of this example is placed in a quartz reaction tube put in an oven, then 1%. Oxygen to nitrogen the catalyst at a rate of 2 cc / g

T8

Catalyst / min. The catalyst is ^{treated at 600 °} F. for 1 hour, then the catalyst is treated at 780 ^° F. for 5 hours. The flow of oxygen will

then stopped and the catalyst to room temperature b

cooled down. The catalyst is then treated three times as follows: (1) Treatment for 30 minutes at 165 ° F with a 10-fold excess of an aqueous solution of hydrogen chloride with a pH of 3, (2) cooling and (3) filter. The catalyst is then treated three times as follows: (1) Treat with 135 ° F for 1 hour a 7-fold excess of a solution of 0, IN magnesium nitrate, (2) cool; and (3) filter. Then the catalyst is treated three times as follows: (1) Treatment at

135 ° F for 1 hour with a 7-fold excess of 15

deionized water, (2) cooling, and (3) filtering.

Then, the Kaltalysator in air at 25O ⁰ F for 2 hours, is dried and treated in flowing air at 500 ⁰ F for 2 hours.

Example 23

The catalyst of this example is placed in a quartz reaction tube in an oven, then 1% oxygen is added in

Nitrogen over the catalyst at a rate of 25

of 2 cc / g catalyst / min. The catalyst is ^{treated at 600 °} F. for 1 hour, then the catalyst is treated at 780 ^° F. for 5 hours. The flow of oxygen is then stopped and the catalyst is cooled to room temperature. The catalyst is then treated three times as follows: (1) treatment with a 10-fold excess of deionized water for 30 minutes at 135 ° F, (2) cooling and filtration. The catalyst is then treated three times as follows: (1) Treatment for 1 hour

at 135 ° F with a 10-fold excess of a solution of 35

0.1N magnesium nitrate, (2) cool and (3) filter.

. 30th

-2 "9-

Then the catalyst is treated three times as follows:

(1) treatment for 1 hour at 140 ⁰ F with a 10-fold excess of deionized water, (2) cooling and (3) filtered. The catalyst is then ^{dried in air at 250 °} C. for 2 hours and ^{treated in flowing air at 500 °} C. for 2 hours.

Finally, Table VI shows 2 unsuccessful treatments, one with a previous acidic treatment and the other without that treatment.

6th
5 Around table VI Mol% Around end .10
.78 At first- 1.
1. 3.05 May be. example May be. .67
26th 30th 22nd
23 27.41
21.82

ic E>ej.fc> pj.fc: .L ums. aei . πυι-ΐ ums . aei. Mole%

1.19 /

The invention is with reference to specific embodiments has been described, but this application is also intended to cover such changes that may be made by those skilled in the art can be performed without departing from the scope and scope of the appended claims

· *
will.

Claims (1)

Claims 1. Process for the rejuvenation of a catalyst, thereby gec indicates that the catalyst with at least 10 ecm of an aqueous medium in the liquid phase per ecm des Catalyst is contacted, wherein the aqueous medium is selected from the group consisting of water, a aqueous solution and saturated water vapor, and the catalyst is a large-pore zeolite, containing at least one Group VIII metal. 2. Method of rejuvenating a sulfur-polluted one Catalyst made from a large-pore zeolite that at least ,, _ contains a metal of group VIII, marked thereby-ο net that (a) the catalyst is exposed to oxidizing conditions in Gewart of oxygen at a temperature of about 200 ° C to about 450 ⁰ C, (b) the oxidized catalyst with at least 500 ecm of an aqueous medium in the liquid phase per ecm of the catalyst with the formation of a moist catalyst is contacted, wherein the aqueous medium is selected from the group consisting of water, an aqueous Solution and saturated water vapor, 25 (c) the moist catalyst is exposed to reducing conditions in the presence of hydrogen at a temperature of approximately 200 ^° C. to approximately 700 ^{° C. and} (d) steps (a) to (c) are repeated until until the catalyst ver-30 to the desired extent is young. 3. Process for rejuvenating a sulfur-polluted one Catalyst according to claim 2, characterized in that the large-pore zeolite is a type L zeolite. 35 4. A process for rejuvenating a soiled with sulfur catalyst according to claim 2, characterized in that the aqueous medium is a basic solution, and the catalyst is contacted with the basic solution at a temperature of about 7O ⁰ C to about 80 ⁰ C. 5. Process for the rejuvenation of a catalyst and for the • j ^ Q improvement of the stability of the catalyst, characterized in that the catalyst with an aqueous Solution of a salt or hydroxide of a metal selected from the group consisting of an alkali metal and an alkaline earth metal is contacted, wherein , g the catalyst consists of a large-pore zeolite which contains at least one Group VIII metal. 6. Method of rejuvenating a catalyst and improving it the stability of the catalyst according to claim 5, “ _N characterized in that the aqueous solution has a concentration of 1 to 8% by weight of metal and 2 to 30 ecm of the aqueous solution are present per g of catalyst. "F- 1. A method for rejuvenating a catalyst and for improving the stability of the catalyst according to claim 5, characterized in that the metal salt or hydroxide consists of potassium hydroxide. _ 8. Process for the rejuvenation of a catalyst and for Ver-υ improvement of the stability of the catalyst, that the contacting is carried out according to claim 5, characterized in that at a temperature of 25 ° C to 100 ⁰ C. --2-2- 9. Method of rejuvenating a catalyst and improving it the stability of the catalyst according to claim 5, characterized in that the catalyst with the c aqueous solution has been contacted, then with 10 to 200 ecm of water per gram of the catalyst for removal is washed from excess metal. 10. Process for the rejuvenation of a catalyst and for _. improvement of the stability of the catalyst according to claim 5, characterized in that the large-pored zeolite is a
Type L zeolite is. 11. Method of rejuvenating a sulfur-polluted one . Catalyst and to improve the stability of the
15th Catalyst, characterized in that (a) the catalyst at a temperature of approximately 80 ^° C. with an aqueous solution of potassium hydroxide
is contacted, wherein the aqueous solution has a concentration of 1 to 8 wt .-% metal, and wherein 2 to 30 ecm of the aqueous solution per gram of the catalyst exist, (b) the catalyst with 10 to 200 ecm of water per
Grams of excess catalyst Metal is washed,
25th (c) the washed catalyst is dried, and with the catalyst off (A) a type L zeolite containing 0.1 to 1.5% by weight of platinum, and (B) consists of an organic binder selected from the group consisting of silicon dioxide,
Alumina, aluminosilicates and clays. 12. A method for rejuvenating a catalyst, thereby marked that > 3-3- (a) the catalyst is washed with a solution selected from the group consisting of a neutral solution and an acidic solution,
5 (b) the washed catalyst with an aqueous Solution of a salt or hydroxide of a metal selected from the group consisting of an alkali metal and an alkaline earth metal, (c) the contacted catalyst with a neutral one Solution is washed and (d) the catalyst, which has been washed twice, is dried, the catalyst being composed of a large-pore zeolite which contains at least one Group VIII metal. 13. A method for rejuvenating a catalyst according to claim 12, characterized in that the metal salt or hydroxide consists of potassium hydroxide. 14. A method for rejuvenating a catalyst according to claim 12, characterized in that the large-pore zeolite is a type L zeolite. 15. Method of rejuvenating a sulfur-polluted one Catalyst, characterized in that (a) the catalyst with an oxidizing gas under conditions that favor oxidation, is contacted, (b) the catalyst is washed with a solution, selected from the group consisting of a neutral solution and an acidic solution, (c) the washed catalyst is contacted at a temperature of about 80 ⁰ C with an aqueous solution of potassium hydroxide, wherein the aqueous solution of potassium hydroxide is a concentration, a from 0.1 to 8 wt .-% Metal, and where 2 to 30 ecm of the aqueous Solution per gram of catalyst are present, (d) the contacted catalyst of step (c) with c 10 to 200 ecm of water per gram of the catalyst for removal is washed from excess metal, (e) the washed catalyst of step (d) is dried and (F) the dried catalyst with an oxidizing _1n the gas is contacted under conditions that a Promote oxidation, taking the catalyst off (A) a type L zeolite containing 0.1 to 1.5% by weight of platinum. And (B) an organic binder selected from the group consisting of silicon dioxide, aluminum oxide, aluminosilicates and clays.