DE1270211B - Process for the production of aromatic hydrocarbons - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
File number:
Registration date:
Display day:

Clog

German KL: 23 b -1/04

P 12 70 211.3-44
July 24, 1962
June 12, 1968

When reforming hydrocarbons, especially petroleum direct distillate fractions Platinum-metal-on-aluminum oxide catalysts play different reactions take place at the same time, such as isomerization, dehydrocyclization, dehydrogenation and hydrogenative cleavage, all of which lead to an increase in the octane number.

Typically, reforming processes are operated at 468 to 524 ° C, 17 to 35 atmospheres, throughput rates from 0.5 to 5 parts by weight per part by weight of catalyst per hour and molar ratios of im Cycled hydrogen to the starting material from 4: 1 to 12: 1 carried out on catalysts that z. B. 0.3 to 1.0 percent by weight of platinum on aluminum oxide. The catalyst gets through Deactivated carbon deposits and must therefore from time to time, e.g. B. by burning, regenerated will.

More recently it is necessary to apply stricter reforming conditions, e.g. B. from temperatures of 482 to 532 ⁰ C at pressures of 7 to 28 atmospheres, because on the one hand fuels with higher octane numbers of 100 or more (unleaded) are required, on the other hand a lot of starting material with high paraffin contents of at least 50 percent by volume is available, which can only be reformed to high octane gasoline under more severe conditions. The lower pressures are used because the dehydrocyclization of paraffins to aromatics increases with decreasing pressure. The advantages achieved in this way usually outweigh the disadvantage of the need for more frequent regeneration of the catalyst.

For certain types of starting material, however, the relationship between yield and octane number is unsatisfactory even with severe reforming conditions. This is particularly true on starting material with paraffin contents of at least 50 percent by weight and naphthene contents of less than 30 percent by weight. The higher the paraffin content and the lower the naphthene content, the more It becomes more difficult to obtain a satisfactory relationship between the yield and the octane number of the Reforming product.

It is known from the literature that water when reforming hydrocarbons on halogen-containing supported platinum catalysts is detrimental in that it leaches the halogen from the catalyst, thereby destroying the equilibrium between the acid function and the metal function in the catalyst and consequently the isomerization and the hydrotreating cleavage are impaired. For the process of producing aromatic
Hydrocarbons

Applicant:

Engelhard Industries, Inc.,

Newark, N.J. (V. St. A.)

Representative:

Dr.-Ing. W. Abitz, patent attorney,

8000 Munich 27, Pienzenauer Str. 28

Named as inventor:

William C. Pfefferle, Middletown, N. J. (V. St. A.)

Claimed priority:

V. St. v. America July 24, 1961 (125 992,
129 935,125 993),
dated September 8, 1961
(136 788)

According to the information in the same reference, the original material should remedy this situation so far be pre-fractionated so that it does not contain more than 0.0005 to 0.001% water, and also the cycle gas should be as dry as possible.

From another literature it is known in the catalytic reforming of heavy gasoline or other paraffin-containing refining products of the premature poisoning of the catalyst thereby to counteract that the heavy gasoline is largely removed from water by previous distillation and clears certain metallic impurities.

The German Auslegeschrift 1 007 922 describes a process for hydroforming sulfur-containing Raw gasoline in the presence of a hydroforming catalyst, in which the sulfur content of the starting material reduced with hydrogen and preferably the amount of water fed to the reaction zone so is controlled that the water content of the gasoline is only 0.0007%. This ensures that the Catalyst maintains its high activity and selectivity for longer.

According to German Auslegeschrift 1 006 104, which relates to a process for reforming gasoline hydrocarbons containing less than 30 percent by weight of naphthenes on a supported platinum catalyst at 480 to 50 ⁰ C, 10 to 30 at and a molar ratio of hydrogen to hydrocarbons

809 559/447

3 4

of at least 8: 1, the water vapor formation conditions should be kept at a temperature in the content of the reaction mixture in a low range of 468 to 532 ° C, a throughput rate of not more than 0.03 percent by volume and 1 to 20 parts by weight of hydrocarbon . In accordance with this, the water charge per part by weight of catalyst per hour, the content of the hydrogen-rich cycle gas should be set to less than a total pressure of about 14 to 49 atmospheres and less than 200 mg / Nm ³ . Ratio of about 3 to 50 moles of hydrogen per mole

On the other hand, in the United States patent specification 2131089 hydrocarbon feed is implemented, which recommends water, when carrying out the dehydrogenation content of the material flowing out of the reactor responses to maintain a high setting of stable working conditions below 0.01% Activity of the activated aluminum oxide kept and the reduction of the catalyst before existing Dehydrogenation catalyst at the beginning of the reaction of the reforming or after the regeneration Mix enough water to add that the catalyst of the catalyst with a hydrogen-containing gas surface is carried out with a monomolecular water layer, is characterized in that is covered. when using a volume of at least 50

U.S. Patent 2,642,383 also recommends 15 percent paraffinic hydrocarbons in the catalytic reforming of hydrocarbon starting material also when starting up at the beginning and substances the water content of the reaction mixture after each regeneration of the catalyst to all increase to the extent of hydrogenative cleavage times when the catalyst is on high to be kept as constant as possible. Temperatures on the order of 454 to

From the USA. Patent 2 952 611 a process is located 20 593 ⁰ C and more and with hydrogen and driving for reforming gasoline for the purpose of producing hydrocarbons for the purpose of reforming motor fuels with high research is brought into contact Water content both octane number of more than 95 (unleaded) in the presence in the entire, the reforming system of a halogen-containing supported platinum catalyst when charged and in the 420 to 570 ° C flowing out of it and pressures below 28 atm known, the 25 good below 0, 01% is kept, carried out in at least four reaction vessels. Preferably, during the above

of which in at least one of the catalyst periods the water content in the reforming daily is regenerated. This process, in the case of the feed supplied as a system and in the one from it Starting material a naphthenic gasoline used, outflowing material kept below 0.0025%, is carried out in such a way that after start-up 30 As catalysts have been found in the invention Reaction vessel in which the catalyst generates rhodium-on-aluminum oxide according to the current process has been established as soon as stable conditions have established catalysts as the corresponding platinum catalysts have proven to be superior to the recycle gas dried so far, since it becomes a stronger selectivity, that the drain from the last reaction vessel did have for the dehydrogenation of naphthenes Contains no more than 0.01% water. It ages more slowly than platinum catalysts. These th process is the measure of drying the two advantages outweigh the disadvantage of the rhodium cycle gas however, not for the entire operating catalysts that they have a lower selectivity for duration and not intended for all times at which the dehydrocyclization of paraffins show, see above those the catalyst at high temperatures with that in the end result with rhodium catalysts Hydrogen and hydrocarbons in contact 40 Product of the same good octane number and roughly the same comes. That the known process is still successful, but the catalyst lasts longer Can be done abundantly is due to the high level of staying active.

Naphthene content of the starting material, because the de- As starting material are in the inventive-

"Hydrogenation of naphthenes to aromatics is known ßen process uses hydrocarbon mixtures, is much easier than the dehydrocyclization 45 which boil in the range of heavy gasoline and 50 to of paraffinic hydrocarbons. It is also noteworthy that 80 percent by volume, preferably 60 to 75 percent by volume, as the U.S. Patent shows, one percent contains paraffins. The higher the paraffin through Temporary higher water content the content of the starting material, the stronger it is Damage to the catalyst that has occurred during the loading process has the advantages of the process according to the invention is reversible if the loading is then noticeable. The naphthene content of the starting material dries sharper again. should be relatively low, but can be up to

It has now been found that when reforming 50 percent by volume.

paraffin-rich, d. H. at least 50 percent by volume. Furthermore, the sulfur content of the in

Paraffins-containing hydrocarbons on platinum - the total charge entering the reaction system, metal-on-aluminum oxide catalysts, is irreversible at all times during the introduction of the relatively severe temperature conditions of the hydrocarbon charge into the system below -454 to 593 ° C, i.e. half by regeneration 0.0025 percent by weight of the total charge irreparable damage to the catalyst.

tors occurs when a certain, very low water- In the interest of a high degree of conversion,

content in the reforming system is exceeded. 60 a high activity and selectivity of the catalyst

The process according to the invention for the preparation and therefore the most favorable relationship between off-aromatic Hydrocarbons from light coal and the octane number of the product are included Hydrogen, in which the dry hydrocarbons - the method according to the invention with high circular material loading with formation of products with hydrogen flow ratios of 10 to 50 mol an octane number (unleaded) of at least 90 in 65 hydrogen per mole of hydrocarbon charge in Presence of dry hydrogen containing in contrast to the usual reforming processes, ie Recycle gas on a reduced platinum metal on which this ratio is usually only 4 moles of water-aluminum oxide ref ormierungskatalysator under fuel per mole of hydrocarbon charge.

5 6

This high hydrogen cycle ratio is also measured. Each batch of catalyst is made with nitrogen

rinsed for reforming in the last reaction unit and then in slow flowing overnight

when using hydrocarbon feeds, reduce hydrogen at 482 ° C and atmospheric pressure

particularly cheap, which gives 50 to 60 percent by volume flavor. The mixture of feed and cycle gas

th included. 5 is passed through the catalyst layer and the

For working according to the invention, it is important to pass the flowing material to a high-pressure separator from Kleidaß the reforming system was pre-dried and fed to the volume, from the top of which a circular platinum-metal-on-aluminum oxide catalyst before the run gas removed and from its bottom an introduction of the hydrocarbon feed into the total product of condensable liquid and System is completely reduced. The gas generated from the reforming io in the process is withdrawn and stored in system supplied fresh catalyst can, for. B. ge a product stabilizer is passed. To disturbances measured U.S. Patent 2,943,044 dried in terms of operating content and flow in will. During the reduction of the platinum oxides the small-volume system to a minimum however, substantial amounts of water arise, and bring the total product over continuously At the end of the catalyst reduction, an air-operated flow control valve can be withdrawn from the water 15, which content of the circulating hydrogen 0.02 until actuated by a counterpressure control register device 0.06%. One has to use this circulating gas stream. The total product is continuously converted into one therefore transferred before the introduction of the hydrocarbon product stabilizer, where a liquid product charge to a water content of less than 5 and more carbon atoms and a gas with 0.01%> preferably 0.0025%, dry. When 20 4 and fewer carbon atoms are obtained. Reduction of the catalyst a hydrocarbon The gas obtained from the stabilizer is measured containing reducing gas is used, and for sampling using a time water content of the solenoid valve controlled by the reforming system in part into an evacuated one Good things derived from butyl rubber at all times during the th gas sampling bag. Catalyst reduction kept below about 0.01% 25 The cycle gas is passed through an alkali scrubber and and the use of lower reduction dryers to give it water and acidic substances, temperature is advantageous. The hydrocarbons such as hydrogen sulfide, to be withdrawn. For loading Charging must also be practically free of matter, using a conventional pressure drop system with a which would form water in the reaction zone. Furthermore, aluminum oxide dryer. The loading will be volumetric the entry of water and matter measured in the 30 metric. With the dryers for the loading reaction zone Water would form in the ref or- sending and the cycle gas becomes the water content mier system from sources other than the feed of the entire feed fed to the system and recycle gas flows, such as the exhaust gas for the waste less than 0.01 volume percent of the total charge sealing of the reactor switching valves with a content in the vapor phase is reduced, and with the alkaline Water and oxides of carbon, that much scrubber becomes the whole of the cycle gas be limited that the water content of the removed from the sulfur. The plant proves to be a reliable reforming system outflowing material at all times for the exact determination of the yield octane points during the introduction of the hydrocarbon number relationship.

Substance feed into the system below 0.01% of the As a feed to the system is a sodium

Total charge is held. If the catalyst is 40 desulphurized, heavily paraffin-containing fraction

Sator must be regenerated, one can lead the re-leads by extraction of a C ₈ reformate fraction

Generation regardless of whether it was obtained in a single and has the following key figures:

nen reaction unit or simultaneously in all Rea- ASTM distillation ⁰ C

tion units takes place, z. B. according to the USA patent specification Boiling Beginning '1211

2 922 766. Then you have to 45 20 ° / 123 * 3

but the catalyst regenerated in this way in the relevant 50 ° / ° 125'6

reduce the reaction units almost completely, 80 ° / ° 1306

and the water content of the hydrogen or the water boiling point 15θΌ

Substance-rich gas with which the reaction units sulfur, percent by weight ''.'.'.'.'.'.'.'.'. θ | θΟΟ13

must be pressurized again, must correspond to 50 density (15 6/15 6 ⁰ CI 0 714

be low before further bringing together the paraffin volume percent 93 *

Catalyst with the hydrocarbon charge naphthene, volume percentage '.'. '!.';.'.''.'. 0

he follows. Aromatics, volume percentage 7

Example 1 Aniline point, C ⁰ 69.39

55 1

20 g of a fluoride-free platinum-on-aluminum oxide. The system is pressurized by injecting hydrogen catalyst (manufactured in plant according to USA.- at a ratio of Patent Specification 2,838,444), which is 0.6 percent by weight 55 moles of gas per Moles of the circulating feed containing platinum will be in the form of 1.6 mm strand. The working conditions, the yield and the compacts in a reaction tube made of stainless steel 60 product characteristics are summarized in Table I, entered with a clear width of 2 ^x / ₂ cm and, unless otherwise stated, the amounts of aluminum oxide with sufficient platelet form of recovery 97% exceed ( in most cases 98%) x 2.38 to 1.41 mm grain size dispersed to give a The yields are given as a percentage of the feed to the catalyst zone of about 250 cm ³ volume and are based on a recovery holding. The reaction device is calculated after each degree of 100%.

Sending in a thermostatically controlled bronze The analysis of the gas and liquid samples

block furnace used. The layer temperatures are hydrocarbons with 1 to 5 carbon atoms

with platinum and platinum-rhodium thermocouples, gas chromatography is used, the analysis of the gas

tests for hydrogen carried out according to O r s a t. All components of a gas sample become independent determined from each other and then for review

added. All values obtained in the gas analyzes are used to calculate the yield under air-free conditions converted.

Table I.

working conditions
Duration of the feed,

hours

Temperature, ⁰ C

Pressure, atü

Throughput speed

Cycle ratio

Yield based on a degree of recovery of 100%

H ₂ , percent by weight

C ₁ -C ₄ , weight percent

C ₅ +, weight percent

C ₅ +, percent by volume

C ₁ , percent by weight

C ₂ , weight percent

C ₃ , weight percent

C ₄ , weight percent

Aromatics, volume percentage based on the charge

Product characteristics

Density (15.6 / 15.6 ° C)

Aniline point, ⁰ C

Aromatics, percent by volume

Research octane number, unleaded .. + 0.792 ml tetraethyl lead per liter

17 to 23 23 to 29 33 to 41 41 to 49 52 to 58 61 to 67 479 480 488 488 488 488 24.6 24.6 24.6 24.6 24.6 24.6 2.0 2.0 2.0 2.0 2.0 2.0 55.0 55.0 54.0 54.0 19.6 7.0 2.6 2.6 2.6 2.6 2.4 1.7 24.9 24.2 28.0 26.3 28.0 33.5 72.5 73.2 69.4 71.1 69.6 64.8 65.1 65.8 61.0 63.2 62.4 59.1 4.0 3.8 4.7 4.6 3.0 2.8 5.4 5.1 6.4 5.9 6.1 7.2 8.6 8.4 9.5 9.0 10.1 12.2 7.0 6.9 7.4 6.8 8.8 11.3 45 45 46 46 44 39 0.800 0.799 0.817 0.808 0.801 0.787 33 33 29 31 32 34 69 69 75 73 71 66 98.8 98.8 102.0 100.9 99.8 99.0 103.0 103.0 105.6 104.9 104.3 104.2

70 to 488
24.6 2.0 55.0

2.0 24.4 73.6 68.6

2.0

5.8

9.1

7.5

38

0.770 41
56
91.6 99.2

Example 2

The same device and a catalyst from the same batch as in Example 1 are used.

The feed comes from the same lot as in Example 1 and is sodium-sulfurized desulfurized by 0.00015 weight percent. The cycle ratio is 7: 1.

Table II

working conditions
Duration of the feed,

Hours 13 to 19 19 to 25 28 to 34 34 to 42 42 to 50 53 to 61 70 to 78

Temperature, ⁰ C 480 480 488 488 489 497 497

Pressure, atü 24.6 24.6 24.6 24.6 24.6 24.6 24.6

Throughput speed 2.0 2.0 2.0 2.0 2.0 2.0 2.0

Circulation ratio 7.0 7.0 7.0 7.0 7.1 7.0 6.9

Yield based on a degree of recovery of 100%

H ₂ , weight percent 1.8 1.7 1.8 1.7 1.7 * 1.6 1.4

C ₁ -C ₄ , weight percent 23.1 22.8 25.8 25.8 25.3 * 29.9 31.2

C ₅₊ , weight percent 75.1 75.5 72.5 72.5 73.0 * 68.5 67.2

C ₅₊ , percent by volume 70.1 70.4 66.7 66.9 67.4 * 62.7 62.2

C ₁ , weight percent 2.3 2.3 2.3 2.3 2.4 2.9 2.8

C ₂ , weight percent 4.3 4.3 4.8 5.3 5.2 6.5 6.5

C ₃ , weight percent 9.2 9.0 9.9 10.0 10.0 11.2 11.6

C ₄ , weight percent 7.4 7.2 8.8 8.2 7.7 9.3 9.8

Aromatics, percent by volume, based on charge 38 37 39 38 38 38 36

Product characteristics

Density (15.6 / 15.6 ° C) 0.770 0.770 0.780 0.778 0.777 0.784 0.776

Aniline point, ⁰ C 41 42 39 40 41 38 40

Aromatics, percent by volume 54 52 59 57 56 61 58

Research Octane Number, unleaded. 93.3 92.8 95.6 95.0 95.0 97.0 95.6

+ 0.792 ml tetraethyl lead per liter 100.0 99.5 102.1 101.6 101.1 102.1 100.9

* Degree of recovery 95.6%

ίο

Comparative example A.

The same device and a catalyst from the same batch as in Example 1 are used. In the first part of the experiment, namely in the 6th to 39th hour, the same loading is used as in the example 1 is used with the modification that 0.04% n-propanol is added to the feed. In the 39th to 56th hours the same charge is used without the addition of n-propanol. The n-propanol addition 0.04% corresponds to 0.012% water. Table III gives the test characteristics and results.

Table III

working conditions
Duration of the feed,

hours

Temperature, ⁰ C

Pressure, atü

Throughput speed

Cycle ratio

Yield based on a degree of recovery of 100%

H ₂ , percent by weight

C ₁ -C ₄ , weight percent

C ₅₊ , weight percent

C ₅ +, percent by volume

C ₁ , percent by weight

C ₂ , weight percent

C ₃ , weight percent

C ₄ , weight percent

Aromatics, volume percentage based on the charge

Product characteristics

Density (15.6 / 15.6 ⁰ C)

Aniline point, ⁰ C

Aromatics, percent by volume

Research octane number, unleaded .. + 0.792 ml tetraethyl lead per liter

6 to 480 24.6 2.0 55.0

2.2

25.6

72.2

65.7

3.2

5.3

9.1

8.0

40

0.789 38 61 94.5 101.3

13 to 480 24.6 2.0 54.0

2.2

23.8

74.0

67.9

3.7

4.4

8.4

7.3

40

0.783
39
59
94.0
100.1

until 30
480
24.6
2.0
7.0

2.7

27.8

70.5

65.3

2.5

4.7

10.3

10.3

37

0.775
42
56
93.8
100.8

30 to 480
24.6 2.0 7.0

1.6

27.3

71.1

66.0

2.2

4.4

10.2

10.4

36

0.773 43
54
93.3 99.9

42 to 480 24.6

2.0

7.0

1.5

27.0

71.5

66.2

1.9

4.8

10.2

10.1

34

0.776 45 51 90.2 98.7

49 to 480 24.6

2.0

7.0

1.5

27.0

71.4

66.5

2.1

4.6

10.1

10.2

33

0.771 45 50 90.0 98.9

The following brief summary of values from Tables I and III shows that water causes dehydrocyclization seriously impaired.

Effect of water on dehydrocyclization (cycle ratio 55: 1)

Tabel

III

Duration of feeding, hours

n-propanol

Research Octane Number

C ₅₊ , percent by volume

17 to 23 23 until 29 6 to 13th 13th until 20 none 0.04% 98.8 98.8 94.5 94.0 65.1 65.8 65.7 67.9

As shown in Table III, by decreasing the circuit ratio from 55: 1 to 7: 1, the hydrogenating cleavage intensified. Moving to a dry feed leads to a drop in octane number of the product without increasing the yield.

Effect of water with a cycle ratio of 7: 1

Tabel

II III

Feed duration, hours

n-propanol

Research Octane Number

C ₅ +, percent by volume

19 to 25 23 to 30th 30 to 37 42 to 49 49 to 56 none 0.04 none 92.8 93.8 93.3 90.2 90.0 70.4 65.3 66.0 66.2 66.5

The values show that charges with excessively high water contents not only lead to a loss of yield, but also lead to permanent damage to the catalyst.

809 559/447

11

Comparative Example B.

The same device and a catalyst from the same batch as in Example 1 are used. The feed comes from the same lot as in Example 1, but is not sodium desulfurized. Charging characteristics:

ASTM distillation, ⁰ C

Beginning of boiling 118.9

20% 123.3

50% 126.7

80% 131.7

End of boiling 164.4

Sulfur, weight percent 0.00074

Density (15.6 / 15.6 ⁰ C) 0.716

Paraffins,% by volume 92

Naphthenes,% by volume 0

Aromatics, percent by volume 8

Aniline point, ⁰ C 69

The operating conditions, the yield and the product characteristics are summarized in Table IV.

ίο The values show a poorer yield-octane relationship and catalyst activity, the effect of the higher sulfur content of the feed even with these low sulfur contents. Instructive is z. B. a comparison of the time

room from the 17th to the 29th hour according to Table I with the period from the 6th to the 22nd hour according to Table IV.

Table IV

working conditions
Duration of the feed,

hours

Temperature, ° C

Pressure, atü

Throughput speed

Cycle ratio

Yield based on a degree of recovery of 100%

H ₂ , percent by weight

C ₁ -C ₄ , weight percent

C ₅₊ , weight percent

C ₅₊ , percent by volume

C ₁ , percent by weight

C ₂ , weight percent

C ₃ , weight percent

C ₄ , weight percent

Aromatics, volume percentage based on the charge

Product characteristics

Density (15.6 / 15.6 ° C)

Aniline point, ⁰ C

Aromatics, percent by volume

Research octane number, unleaded .. + 0.792 ml tetraethyl lead per liter

6 to 13 15 to 22 25 to 32 32 to 39 42 to 49 49 to 56 480 480 479 479 489 488 24.6 24.6 24.6 24.6 24.6 24.6 2.0 2.0 2.0 2.0 2.0 2.0 55.0 55.0 7.0 7.0 7.0 7.0 2.2 2.1 1.8 1.7 1.8 1.9 26.0 25.5 27.1 26.4 28.9 27.8 71.8 72.4 71.1 71.9 69.3 70.3 64.4 65.9 65.7 67.0 63.0 64.0 4.3 4.4 3.6 3.3 4.0 3.6 5.3 4.8 4.9 4.3 5.4 5.2 9.1 8.7 9.3 9.7 10.0 9.5 7.3 7.5 9.3 9.2 9.5 9.5 41 40 38 36 39 38 0.800 0.790 0.778 0.771 0.789 0.789 36 38 40 42 37 38 64 61 58 54 62 60 95.7 94.1 94.2 93.3 96.2 95.2 101.3 100.1 100.2 99.6 101.9 101.4

56 to 63 488 24.6 2.0 7.0

1.8

27.4

70.8

64.8

3.5

5.1

9.6

9.2

38

0.784 40 58 94.5 105.5

Claims (2)

Patent claims: 1. A process for the production of aromatic hydrocarbons from light hydrocarbons, in which the dry hydrocarbon feed to form products with an octane number (unleaded) of at least 90 in the presence of dry hydrogen-containing cycle gas on a reduced platinum metal-on -aluminium oxide reforming catalyst under reforming conditions at a Temperature in the range of 468 to 532 ° C, a throughput rate of 1 to 20 parts by weight of hydrocarbon feed per part by weight of catalyst per hour, a total pressure of about 14 to 49 atmospheres and a ratio of about 3 to 50 moles of hydrogen per mole of hydrocarbon feed reacted, the water content of the The material flowing out of the reactor is kept below 0.01% after stable working conditions have been established and the reduction of the catalyst is carried out before the start of the reforming or after the regeneration of the catalyst with a hydrogen-containing gas d, characterized in that when using a starting material consisting of at least 50 percent by volume of paraffinic hydrocarbons, even when starting up at the beginning and after each regeneration of the catalyst at all times when the catalyst is at high temperatures of the order of 454 to 593 ⁰ C and more Hydrogen and carbons is brought into contact, the water content both in the entire feed fed to the reforming system and in 13 14 the effluent from well below ₀ ° 0.01 I _n contemplated publications /: is maintained. 2. The method according to claim 1, characterized in that German Auslegeschriften No. 1 007 922.1 006 104; indicates that the sulfur content of the French patent specification No. 1,079,373; tion system entering total charge to 5 U.S. Patents No. 2,131,089, 2,642,383, all times during the introduction of 2,952,611; Hydrocarbon feed into the system under Chemisches Zentralblatt, 1959, p. 7677; 0.0025 weight percent of total charge Petroleum Engineer for Management, 1961, May, is held. C 19 to C 31. 809 559/447 5.68 © Bundesdruckerei Berlin