DE2246095A1 - METHOD FOR CATALYTIC IMPLEMENTATION OF A HYDROCARBON FEED - Google Patents

Description

Process for the catalytic conversion of a Hydrocarbon feed

Priority: November 1, 1971, USA, IEi *. 194 465

The invention relates to the regeneration of solid catalysts, which contain metal dehydrogenation components. the Invention gives a new way of reactivating such catalysts after they have come into contact with the coal tank st off -feeding under conditions! have been inactivated, which cause the accumulation of coke or deposits containing carbon dioxide effect on the catalyst. The invention is special advantageous for the regeneration of catalysts in which it is desirable that the dehydrogenation component in the metal sulf id-Porm is present.

Catalysts containing metal dehydrogenation components are used in various processes for treating hydrocarbons used. Examples of this are the conversion of aliphatic hydrocarbons to olefins or of alkylbenzenes to olefinic aromatics, the JSy'droent sulfurization of

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Petroleum fractions, the hydroalkylation of alkyl aromatics and the hydroforming of naphtha compounds. With these Processes generally accumulate on the catalysts carbon-containing deposits or precipitates, so that they are deactivated after a certain period of use will. In the conventional regeneration procedures one usually proceeds in such a way that the catalyst with air or another oxygen-containing gas at an elevated temperature brings into contact with the carbonaceous material burn down. This reaction is strongly exothermic, so that care must be taken that overheating, which the catalyst destroy or damage is avoided; Measures must also be taken to remove hydrocarbons from the Flush out the reaction zone before the oxygen-containing regenerants are added or the remaining regenerants flush out of the zone before introducing further hydrocarbon feed to avoid explosion hazards to avoid.

The conventional approach to catalyst regeneration has a further disadvantage when the metal dehydrogenation component containing catalyst is used in the metal sulfide form and not in the oxide form. That Burning off the carbonaceous material from the catalyst by oxygen causes a conversion of the metal sulfide into the oxide. Although the latter compound also generally has some catalytic dehydrogenation activity However, the metal sulfide often gives better activity so that it can carry out the hydrocarbon conversion reaction this catalyst shape is sought. In order to convert the oxide back into the sulphide it is therefore necessary to use the Treat the catalyst with hydrogen sulfide, carbon sulfide or another sulfur-containing compound until the metal sulfide has formed again. This adds a further step to the process and the period until the

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Plant in turn for processing the hydrocarbon feed can be changed, extended.

It has now been found that solid dehydrogenation catalysts which have been deactivated by carbonaceous deposits or reduced in their activity, 600 ⁰ C can be regenerated successfully by treatment with sulfur dioxide at Temperaturen.oberhalb. This treatment removes the carbonaceous material and restores the activity of the catalyst. This mode of regeneration is applicable to a wide variety of catalysts containing metal dehydrogenation components. Examples of suitable catalysts have been given above. The invention is particularly advantageous when the dehydrogenation components of the catalysts are to be in the metal sulfide form in order to effect the desired hydrocarbon conversion reaction.

The invention thus contemplates catalyst regeneration in a process in which a solid catalyst containing a metal dehydrogenation component has been deactivated by carbonaceous deposits resulting from contact of the catalyst with a hydrocarbon feed at elevated temperature originate. The Rege-.nerierung of the invention is carried out according to the manner that the coked catalyst with sulfur dioxide at a temperature above 600 ⁰ C, usually between 6OO ° C and 800 ⁰ C, preferably in the range of 625 brought into contact to 75o ° C . The bringing of the catalyst into contact with the sulfur dioxide is continued until at least a major part or a major part of the carbon-containing deposits has been removed and the desired catalytic activity has been restored. The catalyst is then reused to treat an additional amount of the hydrocarbon feed. '-

3 0 9 8 ί8 / 113 7

The invention is explained in more detail with reference to the accompanying drawings. Show it

Fig. 1: a diagram showing the removal speed of the carbonaceous deposits from a sulfided bismuth-phosphomolybdate-silica catalyst by treatment with SOp at several different temperatures in the range from 600 to 700 ° C and

Fig. 2: Another diagram showing the influence of temperature on the percentage of carbon removed in one hour in the regenerations indicated in FIG. 1 reproduces.

The regeneration method of the present invention is applicable to those processes in which a hydrocarbon feed at elevated temperature with a solid catalyst which has a metal dehydrogenation component such conditions is brought into contact which cause the build-up of carbonaceous deposits on the catalyst. Examples of such processes are the dehydrogenation of hydrocarbons such as paraffins, monoolefins, and naphthenes Alkyl aromatics, the hydrodealkylation of alkyl aromatics, hydrodesulfurization and hydroforming. For use with Many different catalysts are known for such reactions. The method of the present invention is general applicable to all of these catalysts.

The dehydrogenation component usually comprises one or more Metals from groups I-B, H-B, IH-B, IV-B, V-B, VI-B, VII-B and VIII of the periodic table including any transition metals. The catalyst can still have one component of a metal from groups H-A, IH-A, VI-A and V-Λ. Such catalyst components are often used in combination

3 0 9 818/1137 ^BAD ORIGINAL

a carrier material such as silicon dioxide, aluminum oxide and / or Zirconium oxide or a crystalline zeolite is used. The metal dehydrogenation component is usually in the form of the oxide and / or sulfide. In some cases, however, this can also at least to some extent during the hydrocarbon processing stage of the process are available in elementary form.

In the process of the invention, sulfur dioxide is the only one Regenerative agent used to remove the carbonaceous deposits. As the regenerant essentially consists of SOg and there no significant amounts of If free oxygen is present, it is important to avoid the risk of explosion there is no need to flush the hydrocarbons out of the reactor "before beginning the regeneration stage. Nor is it necessary to do so after the regeneration step and before further introduction of the hydrocarbon feed removed the entire SOO.

The use of SO ₂ instead of oxygen can in many cases also be advantageous because the reaction of SO ₀ with coke in comparison to that of oxygen with coke; is only moderately exothermic. This enables easier control of the regeneration reaction and prevents overheating of the catalyst. Another advantage compared to eggs conventional regeneration with oxygen is present when the metal-dehydrogenation component in place of the catalyst in the sulfide form of _v to be the oxide form, there remains sulfidisrt when using sulfur dioxide as the catalyst regeneration means. This eliminates the time consuming step otherwise required to convert the catalyst back to the sulfide form. Furthermore, this allows the reactor to be switched back to processing the hydrocarbons more quickly. However, the regeneration mode of the invention is also useful when the desired form of the catalyst is the metal oxide form, albeit in such a case the

3098t '$ / t13?

The latter advantage is naturally not obtained and a back-oxidation of the regenerated catalyst before reuse may be required.

^{Temperatures above 600 °} C. are required for effective removal of the carbon-containing deposits from the catalyst by means of sulfur dioxide. This is evident from FIGS. 1 and 2, which will be explained later. As the temperature is increased above 600 C, the increase in coke removal by SO ₂ increases. The temperature used should not naturally be so high that the catalyst is damaged "Suitable regeneration temperatures are generally below 800 ⁰ C. The preferred regeneration temperatures are in the range of 625 to 75o ° C.

The reaction between the carbon and the SO ₂ when the catalyst is treated at the temperatures given above can be represented by the following equation;

2SO ₂ + 2C 5 2CO ₂ + S ₂

It can be seen that the sulfur in the regenerant is reduced to elemental sulfur which leaves the reactor as a gas mixed with carbon dioxide. Virtually no carbon disulfide is formed. Although it is not apparent from the equation, the hydrogen, which is generally present to some extent in the carbonaceous deposits, is converted to water. The sulfur in the outflowing regeneration gases condenses on cooling and can be recovered separately and, if desired, converted back into SO ₂ by incineration.

A preferred field of application of the present invention is in processes in which hydrocarbon feeds dehydrogenated using solid catalysts,

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which contain a metal sulfide dehydrogenation component. After the deactivation of the catalyst regeneration is carried out, wherein the dehydrogenation component in the sulfide form is maintained by is introduced ₂ into the at 600 to 800 ⁰ C, preferably 625 to 75O ° C, held Katalysatorsone easily hot SO until at least a major part of the carbonaceous deposits has been removed. Once the catalyst has been reactivated, it can then be reused to dehydrate another batch of the hydrocarbon feed. Specific examples for this application are the dehydrogenation of isobutane and isobutene using the dehydrogenation promoters described above, for example sulfur or sulfur dioxide and / or mixtures of sulfur dioxide and hydrogen sulfide under dehydrogenation conditions which include a temperature above 500 ° C. are used . In such processes, the catalyst can be repeatedly reactivated by sulfur dioxide without any noteworthy progressive loss of inherent activity being observed.

To illustrate the invention, numerous experiments were carried out in a flow reactor in which an isobutane stream at a temperature above 5oo ° C in the presence of either Sulfur dioxide or a mixture of hydrogen sulfide and sulfur dioxide as a dehydrogenation promoter catalytically to isobutene became dehydrated. Several Dehydrogenation catalysts are used in the sulfide form. After the dehydrogenation stage, during which on the catalyst Coke accumulated, which caused a loss of activity, became the. Coke catalyst treated with sulfur dioxide.

-I

In one series of experiments, the isobaatan dehydration stage was used carried out under preselected conditions so that approximately the same amount of coke deposited on the catalyst in each experiment. The catalyst was then at various temperatures from

309818/1137

Treated 600 to 700 ° C with sulfur dioxide to show the influence of temperature on regeneration. A sulfided bismuth-phosphomolybclate * silicon dioxide catalyst was used as the catalyst, in which approximately the following atomic ratios were present: 9 Bi: 1 P: 11 Mo: 27 Si. It was first prepared in the oxide form as described in US Pat. No. 2,9o4,580 and then sulphided by treatment with hydrogen sulphide at 500 ° C. until the reaction with H ₂ S ceased. A bed of 4 mass volumes of catalyst was used in the reactor in these experiments. The dehydrogenation stage was carried out under the following conditions (flow rate ^{measured at 25 °} C. and 1 atm):

Isobutane rate »22 volumes / min.

SOo speed «8 volumes / min.

HgS speed »18 volumes / min.

Reactor temperature «600 ° C

Reactor pressure ■ about atmospheric pressure

Operating time. " 5 hours

Under these conditions, the catalyst tends to lose only about ho% of its original activity in a 5-hour operating period. After the dehydrogenation period, the flow of isobutane and H ₂ S in the reactor was turned off and the catalyst was heated to the selected regeneration temperature while a stream of helium was passed through the bed. After the desired temperature was reached, a mixture of SO ₂ and helium was passed through the bed at the temperature and rate of 1 volume of mixture / per minute. directs. The rate of removal of carbon from the catalyst was determined by analyzing the effluent gas and calculating the percentage of carbon removed as a function of time. Regeneration carried out at 700 ° C. for 3 hours was used to remove approximately four times the total amount of coke on the catalyst from the

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the standard dehydration conditions specified above.

1 shows a series of curves which shows the influence of the regeneration temperature on the rate of coke removal by SO ₉ , determined in these tests. From Pig. It can be seen that the removal rate is impracticably slow at 600 ° C., but that it increases as the temperature rises above this value. 1 contains values for individual tests at 700.degree. The latter runs were performed essentially the same except that one was run over a three hour regeneration period to effect complete regeneration and thereby determine the approximate total amount of carbon deposited on the catalyst in each run .

In FIG. 2, the percentage of coke, which in a 1-hour Hegenerierungszeitraum in the experiments according to FIG. Are removed 1 are plotted against the "regeneration temperature The resulting curve shows the fact. That the regeneration with SO ₂ temperatures above 6oo ° C This is possibly also the reason why the attempted use of SOp as a regeneration medium has so far not been successful.

After each regeneration shown in FIGS. 1 and 2, the catalyst temperature was set to 600 ° C. and the catalyst was then used for the dehydrogenation of isobutane under the standard conditions given above. The isobutene yields in The effluent was determined after operating times of 0.5 and 50 hours. Average yields were established for the entire 5-hour period. These results are shown in Table I. compiled together with the corresponding regeneration conditions and carbon removal values. After each operating period in the experiments in which the regeneration temperature was below 7oo ° C, the catalysts were before the renewed Use on the next try by about 1-liter

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Treatment with SO ₂ at 700 ° C more completely regenerated. The tests were carried out in the same order as given in Table I.

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Table I Dehydrogenation of isobutane at 600 ⁰ C according to the

Catalyst regeneration by SO

Catalyst: sulfided bismuth-phosphomolybdate Promoter: SO ₂ + HgS

• Isobutene yield, total

Regeneration regeneration temperature, C time, min.

57 60 60 72

69

180

6o

co βοο CD CD 65o CO 675 - »■ 7oo co " 7oo 7oo 625

more distant
Carbon,
% of total
Carbon after a
Operating period
from o, 5h after a
Operating period
from 5 h through chs chni 11 Ii <h
for a Be
driving period
from 5 h 4th 32 · 23 25th 44 41 27 32 68 4o 27 87 41 , -28 35 • 94 41 29 35 loo 42 29 37 18th 4o 28 35

The values in Table I show that the sulfided bismuth-phosphomolybdate catalyst even after a significant coke deposition (i.e. after an operating period of 5 hours) Had there still been significant dehydration activity would have. For comparison, it is stated that when using an inert contact material such as molten aluminum, in the reaction zone instead of the catalyst an average 5 hour yield of isobutene in the region of lo ^ obtained would be. The values given also show that the activity of the catalyst used by treatment with SOp can essentially be restored, provided that the reactivation temperature is above 60 ° C and that the treatment period is sufficient.

The catalyst used in the experiments in Table I had previously been used in a number of consecutive experiments in which isobutane _{had been dehydrogenated by H 2} S and SO ₂ at the standard conditions given above C regenerated by treatment for 1 hour with a 50: 50 mixture of SO ₂ and helium.These combined with all experiments, with the exception of the last one in Table I, resulted in a total of 20 successful experiments in which the catalyst had been regenerated _{with SO g.} In Table II values are compiled which compare the results of the first and the twentieth test of this series with one another.

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Table II

Dehydration of isobutane in consecutive

' Try ■ ____

Catalyst: sulfided bismuth-phosphomolybdate

Dehydrogenation isobutane-order selectivity too

Test temperature C conversion, # * isobutene, % ■% ■■

first 2o.

6oo 600

29 39

$ 0 88 Amount of coke, based on the isobutane charge, %

2A

average for an operating period of 5 hours

j> cn ο

CD CTJ

22A6095

The values in Table II show that the catalytic activity after the 2o. Try about the same as naoh dem first attempt, and that through this series of experiments no noteworthy progressive weakening of the activity had taken place. Further tests with this catalyst have shown that it can be used for many more operating cycles can be used without a significant decrease in activity and can be regenerated if it is kept at temperatures in the

> 2

_{Treated with SO 0 in the} range from 625 to 75o ° C.

Using another batch of bismuth-phosphomolybdate catalyst that _{had been treated with H 2} S, another series of isobutane dehydrogenation experiments was carried out. In these experiments, the isobutane dehydrogenation was carried out using only SOo in a 1: 1 molar ratio to the feed as the dehydrogenation promoter at 600 ° C. The regeneration steps were carried out at the temperature, time and gas hourly space velocity (GSRG) conditions set out in Table III. Table III also gives values for the dehydration stages at the beginning and after several regenerations.

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Tabel

III

Successive dehydrogenations of isobutane 'at 600 ° C
after catalyst regenerations, at different

Conditions,, '■

Catalyst: sulfided bismuth phosphomolybdate _·:
Promoter: SO _0. '. ■: ■' ■

K) 4> CD O CO CJl

O CD OO

Regeneration stage (with SOg)

_ go * __! £ GSRG time ^ min.

No.

11

75o

1500

25th

Operating level

■ XsQDutan- Utti 'conversion;,. gg!

24
• 54
5o

Isobutene.,

37

⁷ p. 78

75

1 650 - 75o 250 1.50 ■ ■ '< 8th 64 72 27 • 59 78 ^ 74 ^: ' .60 35 $ 84 3 680 75o 250 I05 3 '57 ·' ■ ■ 53 2o 58 "35 -. '' ■.: '' ■ 58 ... 33 ÖO 4th 680 250 . Ho 2 65 ■■ · 44 17- 64 - i 79 .57 ■ 31. ' 84 7th 250 · 2 : ■ 46. ■ · ■ · 32 21 78 75 58. . 64 • 75 9 630 2 49 ■ 44 21 ' ... 74 74 56. ■ 67 74

The values in Table III show. \ beneath regeneration conditions the catalyst by .the ·. Treatment with SO ₂ was essentially regenerated. "In fact, after the first reaction, the catalyst actually became more active than it originally was. This improvement in catalyst activity is not yet completely known with certainty “That this is due to a stronger sulphidation of the catalyst as it continues to operate.

After the operation of the US patent 2 9 © 4l · .580 more Wisraut-phosphomolybdate catalysts were prepared, except that in each Io mole # IJlteats one, or a chloride -zugegeben one of the following metals. "Nurde" by the initially used aqueous mixture of phosphoric acid, molybdic acid, nitric acid, bismuth trinitrate mod colloidal silica sol with the nitrate or the chloride of K ₀ Ca ₉ H ₉ Co; Ni, Cu, Pd, Ag, Sn, VJ, Pt, Au and Pb were added. The catalysts obtained in this way were examined with regard to the activity in the dehydrogenation of isobutane by SO ₂ as hydrogenation promoters. They showed active bags * which were not very different from those of the catalysts used in the experiments in Table III.

With the standard dehydration conditions of the fersiaefie of Flg. and 2, an itolybdenum disulfide silicon dioxide catalyst was used in a series of isobutane doohydration experiments at 600 ° C. The catalyst was manufactured in such a way that MoS _{2 was} mixed with an aqueous colloidal silica sol, and the mixture was dried, by sieving a fraction with ο, ΒΜ to 9 mm (2o to 3o mesh) separated rare vmä this fraction was _{calcined in an IL 1} S stream at 600 ° C

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followed by a catalyst regeneration stage. For comparison purposes, two different regeneration procedures were used. One regeneration was carried out according to the present invention by treatment with a mixture of SO ₂ and helium in equal volumes at 700 ° C. at atmospheric pressure: and a rate of about 27 vplumina / min. per volume of catalyst over a period of 1 hour. The other regeneration was carried out using γοη O ₂ , diluted with helium in a volume ratio of 1: 9, at atmospheric pressure and at a rate of about 12 volumes / min, per volume of catalyst. Since the use of oxygen to burn off the carbon results in a strongly exothermic reaction, the catalyst temperature was only increased by one to 500 C before the oxygen-helium mixture was introduced. Avoid overheating. It took about 1 to 2 hours to at. Burn off the carbon under the specified conditions. During this period the measured catalyst temperature rose to about 550 ° C., although the surface temperatures of the catalyst can be considerably higher. In the experiments in which SO _{2 was used} as a regenerant, no significant increase in the catalyst temperature was found. The results of this series of tests are shown in Table IV.

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Table IV

Successive dehydrogenation of isobutane at 600 ⁰ C
using SOp or O ₂ regenerants

catalyst
Promoter

MoS ₂ -SiIiCiUm
SO ₂ + H ₂ S

Regeneration level Regeneration
medium temp., C ... _-- Time, min. Isobutane-Um
transformation, fo * Operating level Amount of coke, related
on the isobutane
Loading, fo Approx
O
CO No. : Hey 7oo 45 47 Selectivity too
Isobutene, % * 4.4 CO O SO ₂ : 9He 500-550 . 45 43 53 '4, o ö ^ CO 1 ° 2 : Hey 7oo 45 38 64 2.2 - * 2 so ₂ : 9He 500-550 3o2 ', 36 63 2, o 3 ° 2 : 9He 500-550 293 42 82 1.6 4th Oo 45 41 84 2.4 5 68

Average value for the entire operating period

CD O CX) CJl

The results of table 3IF can be seen, that the &ktlirl; ät of the -catalyst can be produced by Begenerlerang with SOp ©, so that none of the activities of the regenerated catalyst is worth mentioning . It becomes pear. The following regenerations, regardless of whether SOo or Op were used as explanation means, showed that the catalyst was regenerated twice In addition to the catalytic activity in the case of activation with QO ₀ instead of iron D, _o no ortell occurs, the use of SO ₂ cten has a distinct advantage with the fact that a strongly exothermic reaction is avoided, which would otherwise lead to the formation of Could cause hot spots, which could cause catalytic converter damage over extended tent spaces of the catalytic operation.

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Claims (8)

Claims 1. Process for the catalytic conversion of a hydrocarbon feed on a solid catalyst containing a metal dehydrogenation component at an elevated temperature, in which carbon-containing deposits accumulate on the catalyst and lead to a reduction in the catalytic activity Lead activity, thereby g e k e η η ζ ei c h η et, that the catalyst is regenerated by treating it with sulfur dioxide as the only regeneration agent at temperatures above 600 ° C brings into contact until at least a larger part the carbonaceous precipitate has been removed. 2. The method according to claim 1, characterized in that one at a temperature in the range of 625 to 75o ° C works. 5. The method according to claim 2, characterized in that a pesticide catalyst is used, which contains a metal sulfide as the dehydrogenating component. 4. Process for dehydrogenating a hydrocarbon feed using a pesticide catalyst which contains a metal sulfide as a dehydrogenation component under dehydrogenation conditions, in which carbon-containing deposits accumulate on the catalyst, characterized in that the catalyst is maintained while maintaining regenerated the dehydrogenation component in the sulfide form by one the catalyst with a regenerant which irr; consists essentially of sulfur dioxide, at temperatures in the range from 6oo to 8oo ° C brings into contact until at least one larger part of the carbonaceous waste! fertilize has been removed BATH ORIGINAL 3098 18/1137 ^ - 21 - that is and that the regenerated catalyst is used again Dehydrogenation of another amount of the hydrocarbon feed used. 5. · The method laughs at claim 4, characterized in that one at a temperature in the range works from 625 to 75o ° C * ■, 6. The method according to claim 4, characterized in that g e k e η η, that isobutane with sulfur, sulfur dioxide and / or mixtures of sulfur dioxide with hydrogen sulfide as a dehydrogenation promoter on the solid catalyst under dehydrogenation conditions which are a temperature above 500.degree include, in which carbonaceous precipitates accumulate on the catalyst and lead to a reduction in the lead to catalytic activity, 'dehydrated to isobutene, whereby the catalyst while maintaining the dehydrogenation component regenerated in the sulfide form by treating the catalyst with sulfur dioxide at a temperature in the range of 625 to 75o ° C until at least a larger part of the carbonaceous deposits has been removed, and that thereupon the regenerated catalyst again 'for further conversion of isobutane to isobutene is used. 7. The method according to claim 6, characterized in that there is sulfur dioxide as the dehydration promoter used. ■ 8. The method according to claim 6, characterized in that a mixture is used as the dehydration promoter used from sulfur dioxide and hydrogen sulfide. BATH ORIGINAL 309818/113 7 Blank page