DE1645819C - Catalytic reforming process - Google Patents

Description

3 4

35 atü worked. A special limitation of the water oil, a coal tar distillate, a shale oil or the like,

salary is not provided. which boils in a given temperature range. the

Surprisingly, it has now been found that the expression denotes "in the presence of sulfur" through a very specific selection and combination, a state in which the sulfur, in general the process parameters pressure, water content and S in the form of hydrogen sulfide, in intimate ver-sulfur content a process-technically flawless mixture with the reactants in the re- and simple implementation of a reforming process forming zone is present, the specified total f For hydrocarbon feeds the gasoline boiling amount of sulfur is the total amount of equivalent range at relatively low pressure with very little sulfur in sulfur-containing compounds that come from Deactivation rate of the catalyst, i.e. long ι ο any source in the reforming zone, Operating periods, is made possible. One is designated. The sulfur concentrations are included Series of undesirable quality-reducing reactions calculated as parts by weight of sulfur per 1 million largely suppressed, resulting in a corresponding part by weight of feed (ppm) and stated on Increase in performance, the basis of action of elemental sulfur, even if the degree, the yield and the stability of the reforming 15 sulfur is present in the form of a compound. the mation leads. Furthermore, the term "practically anhydrous environment" denotes the selectivity reforming improved. The formation of carbon-net a state in which the total amount of Containing deposits on the catalyst will despite water from the feed and from water-forming lower operating pressures strongly pushed back. The compounds formed by water that result from somehow benefits show up especially when the 20 of a source enters the reforming zone, few! al yield of hydrocarbons with 5 and more 20 parts by weight per million, based on the carbon atoms at low hydrogen partial hydrogen loading, and preferably substantially press should be brought to a maximum value, less than this amount. The expression "redud. H. under conditions where previously large, difficult sulfur-containing compounds «denotes verkeiten by contamination and deactivation of the 25 bonds, which are under the in the reforming zone herr-catalyst occurred. Seeing conditions result in hydrogen sulfide

For this purpose, the invention relates to a catalyst and no oxygen. The expression »Setisches Reforming process of the selectivity specified at the beginning «describes the capability of the process. Type, which is characterized in that the desired octane number-improving reactions are implemented at a pressure in the range of 5.1 to 30 to inhibit favorable and undesirable reactions. 20.4 at in a practically anhydrous environment, in The term "activity" denotes the ability to which the total amount of water from the feed producing a product of the desired quality, and water-forming compounds, measured by the octane number. The expression »Stabi-Wasser Less than 20 parts by weight per million, “weight” denotes the extent to which changes are required on the hydrocarbon feed, 35 ments of operating parameters of the process, and in the presence of 10 to 3000 parts by weight moved over time; a common measure of stability For example, sulfur per million parts by weight of the feed is the change in reactor temperature performs. per unit of time that is required to achieve a predetermined

Preferably, a hydrocarbon feed quality of the product produced is maintained, kung fed the oxygen-containing compounds in 40 with a lower slope a more stable combiner Contains amount that indicates less than 5 parts by weight driving. The expression “Platinje Million water, based on the charge, “de-grouping metal component” includes all elements of the stand, and about 10 to about 1000 parts by weight per group VIII of the periodic table with one atomic million, Calculated as equivalent sulfur, by weight over 100, as well as compounds and mixtures contains sulfur-containing compounds. 45 of them. The »hourly room flow velocity

Due to the special selection and combination of the liquid «is defined as units of volume

the specified operating parameters are operating on supplied liquid feed per hour and per

Implementations at relatively low pressures are not unit volume of that in the reaction zone

only possible, but also very useful. With the catalytic converter.

in the examples below, naphtha

In most cases fractions containing thene and paraffins were processed,

worked at a pressure of only 6.8 at. Such preferably those that are mainly made of naphtha

low pressures are for technically longer thenen and paraffins exist, however can also

Operating periods to be carried out reforming aromatics and / or olefins be present. Preferred

unusual. Nonetheless, as the subsequent 55 z. B. Straight-run gasoline, natural gasoline and the like.,

The information given is evident, but high selectivities are often also thermal or catalytic

and yields of the desired products in the case of cracked gasolines or higher boiling fractions

high catalyst stability achieved. of these or mixtures of straight-run and

Before further explanation of the process, gasoline cracks would be advantageous. It can be

a number of the expressions used here are defined. 60 a gasoline with an initial boiling point of about 10

The term "gasoline boiling range" denotes Koh- to 38 ° C and a boiling point of about 169 to

lenwasserstoffgemische with an upper boiling limit 219 ⁰ C or a fraction thereof, usually at

from about 204 to 219 ° C. The term "naphtha" is a higher-boiling fraction, as it is commonly called

denotes a distillate boiling in the gasoline sector is referred to as heavy naphtha or heavy gasoline,

with an initial boiling point usually around 65. Pure hydrocarbons can also be used

66 to 121 ° C and a boiling point of about 177 or mixtures of pure hydrocarbons, usually

up to 232 ° C. The expression »hydrocarbon fraction paraffins or naphthenes, which convert to aromatics

or distillate «denotes a fraction of a raw material to be converted. How after-

5 6

is shown on the basis of an example, suitable and / or chlorine, in an amount of about 0.1 to 1.5% the process is particularly suitable for the conversion and in particular about 0.4 to 0.9 percent by weight, from acyclic paraffins to aromatics in good The platinum group metal component can example yields with constant operating conditions, either by impregnation or mixed precipitation with which is a particular advantage of the method dar- 5 a platinum group metal compound, z. B. Platinum, hydrochloric acid, platinum cyanide, platinum hydroxide,

In general, it is preferred to first use the platinum sulfate, palladium sulfide or palladium chloride, Sulfur and oxygen concentrations of the feed are introduced, whereupon the material is dried materials to very low values and and then a calcination and, if desired, then a regulated amount of hydrogen sulfide io further treatments, e.g. B. a reduction and / to introduce forming compound, since a preparation or sulfidation can be subjected. the Drawing of the catalyst already present in the feed can be in the form of spheres, pills, extruded sulfur compounds to set the final date, powder or granules are used. Sulfur content is usually difficult to control. The reforming can be done according to modes of operation Compounds which form hydrogen sulfide are fixed catalyst bed, fluidized bed and slurry particularly suitable: aliphatic mercaptans, ζ. B. or moving bed, Ethyl mercaptan, propyl mercaptan and tert-butyl, preferably with a fixed bed with regard to this mercaptan; aromatic mercaptans, ζ. B. Thio- lowest abrasion losses of the catalyst. the phenol and derivatives thereof: cycloalkyl mercaptans, sulfur-containing component can be added to the feed z. B. cyclohexyl mercaptan; aliphatic sulfides, e.g. B. 20 are added continuously or intermittently, Ethyl sulfide; aromatic sulfides, e.g. B. phenyl sulfide; z. B. at the inlet of the catalyst belt, at one point aliphatic disulfides, ζ. B. tert-butyl disulfide; aroma- downstream of the inlet or in several places, table disulfides, e.g., phenyl disulfide; Dithio acids; or, if several reactors are provided, in Thioaldehydes; Thioketones; heterocyclic sulfur the first, in one of the following or in several connections, ζ. B. Thiophenes and Thiophanes. White of the reactors. It can also be found in the water rich Thereafter, free sulfur or recirculation gas or in operating modes in which water-hydrogen sulfide is required are "always" desirable be used. Usually solid gas supplied from an external source will, for the sake of cost and convenience, be meddled into this. It is common a mercaptan, ζ. B. tert-butyl mercaptan, preferred. most convenient to use the sulfur-containing component

To mix the sulfur present in the reforming zone with the hydrocarbon feed, In a preferred embodiment, the amount of the hydrogen-rich recycle process is expedient depending on the amount of sulfur flow, entirely or largely of hydrogen sulfide hydrogen, which zui ück- and freed water in the hydrogen-rich gas and the required amount of is performed, and the composition of the use of reducible sulfur compound according to one of the primary materials. It is to be introduced into the reaction zone from all sources, taken, 10 to 3000 parts by weight of sulfur each because this is a relatively cumbersome over-1 Million parts by weight of the feed and preferential control of the return flow to prevent a wise about 15 to about 2000 parts by weight per million increase in concentration of hydrogen sulfide and be. In the preferred mode of operation, which in particular avoids water. This can be considerable proportion of the hydrogen-containing gas 40, for example, by passing the recycle gas over from the effluent of the reforming zone without further sodium large surface, aluminosilicates, mole treatment is returned to the reforming zone, kularsieben, aluminum oxide, silicon dioxide gel or is in the feed a reducible sulfur ion exchange resin, or by solvent exchange preferably in an amount of about 10 traction with organic solvents, e.g. B. Dibis about 1000 parts by weight per million equivalent - 45 ethylene glycol or diethanolamine, happen, contain sulfur. The process is carried out at pressures from 5.1 to 20.4 at

A conventional re-operation can be carried out in the process. The operational forming catalyst selected in the individual case is used, which contains a pressure that is primarily based on the platinum group metal component of its own. Platinum will be used as the feedstock. For example, it was preferred, but other platinum groups are also suitable for good stable operation in conjunction with a metal, ie palladium, rhodium, ruthenium, os- light Kuwait naphtha at such a low pressure, mium and iridium. The platinum group metal, such as 6.8 at, as can be seen from the examples, usually makes about 0.01 to 3.0 and the temperature required in the reforming zone usually about 0.1 to 2.0 percent by weight of the catalyst is with comparable others Conditions deeper than sators, computed as an element. The metal component in conventional operations is under nent with a heat-resistant inorganic high pressure. In general, at temperatures of oxide carriers of synthetic or natural origin, about 427 to 593 ⁰ C and preferably about 454 to z. B. aluminum oxide, silicon dioxide, zirconium 566 ° C can be worked.

Oxide, Magnesium Oxide, Borium Oxide, Thorium Oxide, Titan- The procedure is usually carried out with an oxyd or strontium oxide or mixtures of two fluid space velocities or more such components, e.g. B. SiIi- from about 0.5 to about 15.0 and preferably about 1.0 ciumdioxyd-aluminum oxide, aluminum oxide-boron up to 5.0. The amount of hydrogen rich oxide or silicon dioxide — aluminum oxide — zirconium gas, which together with the hydrocarbon oxide etc., united. It is preferred that the alumina charge is supplied, is expediently about in all of its states, either alone or from 0.5 to 20 and preferably from about 4 to 12 moles of water in Mixture with one of the listed heat-resistant substances per mole of hydrocarbon, digen oxides. The catalyst preferably contains. Another particular advantage of the process is that it is rare Bound halogen, especially fluorine, with which the catalyst must be regenerated.

Conventional working methods at low pressure required extensive regeneration facilities, when the catalyst should be used for an economically feasible length of time. In contrast can the method described here due to its good stability at low pressure and as a result the low catalyst fouling and deactivation rate without expensive regeneration facilities, such as switching reactors, are built and operated, resulting in great savings Investment and operating costs.

The following examples serve to further illustrate the process and the results achieved technical advantages.

example 1
(Comparative example)

This example illustrates the effect of reducing the pressure when processing a light Kuwaiti naphtha using a conventional reforming catalyst.

The catalyst was prepared using 1.6 mm alumina spheres that were 0.90 weight percent contained combined chlorine. The beads were initially with a sufficient Amount of an aqueous solution of chloroplatinic acid, around 0.75 percent by weight of platinum, calculated as metal, introduce mixed. The impregnated spheres were then dried and then subjected to high temperature oxidation and then high-temperature reduction treatment in a hydrogen atmosphere subject. The reduction treatment was followed by a high-temperature sulfidation treatment where the catalyst composition is in an atmosphere containing hydrogen sulfide was exposed. The resulting catalyst contained 0.75 weight percent platinum, 0.90 weight percent Chloride and about 0.01 weight percent sulfur, both calculated as elements.

The feed used in this example was a specially manufactured Kuwaiti lightweight naphtha with the properties listed in Table I.

Table I.
Light Kuwait naphtha

Specific weight at 20 ⁰ C 0.7238

100 ml ASTM distillation, ⁰ C
Initial boiling point 80

5 ° / o 86

10% 90

3O ° / o

90 "/"

95 ° / "

End of boiling point

Sulfur, parts per million

Nitrogen, parts per million

Water, parts per million

Octane number, F-I clear

Octane number, F-I 4 3 ml tetraethyl lead /

3.785 liters

Paraffins, percent by volume

Naphthenes, percent by volume

Aromatics, percent by volume

95

103

112

122

126

135
1.6
0.79

<2
50.4

73.8

74.0

19.0

7.9

The salting material was used for a number of activity stability tests; this became the Einsatzmaierial with a fresh filling of

ao 100 cm ^{3 of} the aforementioned catalyst passed, at an hourly space flow rate of the liquid of 1.5 and a hydrogen ratio of 12 moles of total recycle gas per mole of hydrocarbon charge. The test period was 6 days. The target octane number, ie the specified octane number to be maintained, was 100 FI clear, and the temperature was constantly readjusted during the tests in order to maintain this target octane number.

The tests were carried out in a reformer which had a single reforming zone, a separation zone and a debutanization column. The effluent from the reforming zone was passed into the separation zone, which was maintained at the same pressure as the reforming zone but at a temperature of 13 ° C. A portion of the gaseous effluent from the separation zone was returned to the reforming zone in order to supply the required hydrogen and to maintain the pressure in the reforming zone. The excess gaseous effluent from the drying zone was obtained separately. The liquid effluent from the separation zone was fed to the debutanization column, and there the light ends, ie hydrocarbons in the range from C 1 to C ₄ , were removed. The C ₆ + product from

♦ 5 of the debutanization column was obtained separately and analyzed.

The purpose of the series of experiments was to reduce the pressure to a greater extent Keeping the previously specified process variables constant to investigate. Selected results of this series of tests are given in Table IT listed.

Table II
Summary of operations with change in pressure

temperature EBK / GES * Q + yield H, in the return gas Volume percentage Pressure in the system Gas ratio Aromatics ⁰ C Volume percentage V. in the product atO 537 0.176 66.9 74.6 on loading 20.4 533 0.108 70.5 80.3 45.4 13.6 531 0.078 72.3 81.4 48.4 10.2 529 0.053 73.2 82.6 50.7 6.8 50.3

EBK / GES = Entbutanisicrkolonncngas / Gcsamtgas ..

209638/215

This table shows the results obtained at the end of the fourth day for each of the tests. The terms used in Table II have the following meanings:

A. EBK / GES gas ratio is the volume ratio of the overhead gas from the debutanizing column to the total gas generated in the system (excess separator gas + debutanizing column gas). This ratio is a measure of the relative yield of undesirable light products the reaction, especially in connection with the purity of the recycle hydrogen, and it is so far a measure of the relative stability of the catalyst, since an instability of the catalyst of an increase accompanied by undesirable excessive hydrocracking to light gases.

B. The C ₅ + yield in percent by volume is the volume of the product, a percentage of the initial charge, which flows from the bottom of Entbutanisierkolonne, this is generally the characteristic value with the greatest economic importance.

C. The value of H ₂ in the recycle gas, ° / ", indicates the molar percentage of hydrogen gas in the recycle stream to the reforming zone.

D. The value by volume percent aromatics indicates the volume of aromatics produced, expressed as a percentage of the total volume of feed. Because the aromatic content is the main characteristic the octane number is improvement, it forms an approximate value of the selectivity of the process for the quality-improving reactions explained above.

Thus, from Table 11, it can be seen that a decrease in the operating pressure results in the following Appearances leads to:

A. When the pressure was reduced, the EBK / GES gas ratio fell, and the purity of the recycle hydrogen stream increased; this shows that an essential Reduction of undesirable hydrocracking to light gases occurred.

B. The decrease in undesirable hydro cracking was a parallel increase in

. C ₅ + yield accompanied.

C. Reducing the pressure further increased the purity of the recycled Hydrogen, primarily due to the decrease

ίο the production of light gases by way of the unwanted hydrocracking.

D. The reduction in undesirable hydrocracking was an increase of the preferred quality-improving reactions, which can be seen from the aromatic values in percent by volume. Furthermore, it can be seen that the reduction in pressure leads to a considerable decrease in the reactor temperature, which are adhered to at the end of four days in order to achieve the target octane number

ao had to, was accompanied. In view of the strong dependence of the hydrocracking reaction on temperature this was another factor in the direction of the least amount of undesirable effects Hydrocracking.

However, the results that can be achieved in accordance with the above explanations are not without simultaneous attendant disadvantageous phenomena. This is illustrated in Table III. It it can be seen that the decrease in pressure is accompanied by a decrease in temperature and yield stability is accompanied. As explained at the outset, this is based on the rapid decrease in catalyst activity for the quality-improving responses to this pressure reduction, which is likely to be a complex function of increased carbon deposition on the active sites of the catalyst is.

1st day Table ul
Temperature stability values +11
i +13
: +14
¹ +16 C ₅ + - /
1 day yield, percent by volume
Day 6 Λ yield System pressure
atü 527
522
520
518 Required temperature, C
Day 6 Λ Τ 68.5
71.7
74.6
77.4 65.9 i
69.2 I.
70.4!
72.4! -2.6
-2.5
-4.2
-5.2 20.5
13.6
10.2
6.8 538
'535
1 534
i 534

So the values of this example illustrate the very substantial octane yield improvement that by reducing the reactor pressure to suppress hydrocracking and promote Flavoring can be achieved. But they also show the problem of the reduction in stability has hitherto prevented the application of lower pressures and must be overcome in order to obtain these advantages to be able to use it to the full technically.

Example 2

This example illustrates the advantages achieved by the method according to the invention in terms of the dehydrocyclization reaction, d. H. improve the reaction with the highest octane number Potential. This quality-improving potential is best illuminated by the fact that paraffins with octane numbers of 10 become aromatics with a mean mixed octane number of 130 can be converted.

A sample of n-nonane (purity: 99.7%), with a Content of 0.4 parts per million sulfur and 6 to 7 parts per million water was found on a catalyst implemented containing 0.9 percent by weight of combined chlorine and 0.75 percent by weight of platinum and according to the method explained in Example 1 had been prepared. The reforming was initially over a period of 6 hours at a temperature of 500 ° C and then for a period of 6 hours

carried out at a temperature of 520 ° C; the pressure was maintained at 6.8 atmospheres and the hourly space velocity of the liquid was 1.5 and the hydrogen to hydrocarbon molar ratio was maintained at 7.5.

The operating runs were carried out according to practically the same flow sheet as in Example 1, with the exception that there is also a scrubber with a large sodium surface to dry the discharge from the reforming reactor and hydrogen recycle stream.

Two runs were carried out, relevant results of which are shown in Table IV are.

Table IV

Summary of results of the nonane tests

Operating
run
No. Sulfur addition,
Parts per million Q +.
Volume percentage
the
feed Aromatics,
Volume percentage
the loading 1
2 0
73 72.4
73.1 59.3
63.2

From the table it can be seen that the addition of sulfur, it was in the form of tert-butyl mercaptan, and the almost complete absence of water from the recycle stream of hydrogen at equal with all other variables to a 0.7 ° / ₀ strength improvement of the C ₅ + Yield in percent by volume, based on the feed, and led to a 3.9% increase in the aromatic content of the C ₅ + product fraction. These results clearly show a significant increase in aromatization reactions and a decrease in nonselective hydrocracking reactions.

The octane numbers of the products were not determined in this case. An analysis of the results on the basis of octane numbers, the improvement achieved according to the invention would be even more pronounced show, especially because the octane number is approximately directly related to the aromatic content of the product changes. However, the aromatics yields clearly indicate the degree of improvement to be expected again.

It should also be noted that if the operating runs are carried out at constant octane number (i.e. in this case with an approximately constant aromatic content) when carrying out the operation according to the invention, substantially lower reaction temperatures would have been sufficient to produce equivalents Get results.

Example 3

This example illustrates the adverse effect of the presence of water on the process according to the invention.

A desulfurized Kuwait straight run naphtha, the properties of which are given in Table V below are listed, was over a reforming catalyst of the same composition and manufacture how the catalyst of Example 1 reformed. The operating conditions were as follows: A pressure of 6.8 atm, a liquid hourly space velocity of 1.5 and a molar ratio of Hydrogen to hydrocarbon feed of 7.5. The operating temperature was readjusted during the operating runs so that an octane number of the debutanized liquid product of 100 F-I was maintained clear.

The flow sheet was essentially the same as that of Example 1, except that High surface area sodium scrubbers were added to virtually the total amount of hydrogen sulfide and remove water from the recycle hydrogen stream.

Table V

Properties of the light Kuwait naphtha 100 ml ASTM distillation, ⁰ C

Initial boiling point 82

5% 90

10% 92

30% 96

50% 101

70% 106

¹ S 90% 118

95% 124

End point of boiling 151

Sulfur, parts per million 0.2

Nitrogen, parts per million 0.1

Water, parts per million <1

Paraffins, percent by volume 76

Olefins, volume percentage <1

Naphthenes, percent by volume 18

Aromatics, volume percentage 6

The purpose of this series of experiments was to investigate the effects of water (which is chemically added to the feedstock) was added in the form of tert-butyl alcohol) the reforming of the naphtha charge in the presence of 10 parts per million sulfur (the dem Feedstock in the form of tert-heptyl mercaptan was added) to investigate.

The results are shown in Table VI by the reactor temperature and the C _s + yield, in percent by volume of the feed (ie the yield of pentanes and heavier components), at the end of the first 24 hours (referred to in the table as "Beganf") and on End of the 144-hour test given. Runs 1 and 2 were terminated prematurely because of excessive deactivation, so that the values given for these tests are those which were obtained in each case immediately before the test was terminated. Runs 4 and i were carried out under similar conditions with the only exception that run 5 added 2 parts per million of chloride in the form of tertiary butyl chloride to the feed. Operation run 5 represents an experiment carried out in accordance with the requirements of the method according to the invention. Operation run 6 i: a further control test which, compared to operation run 5, shows that a minimum concentration of sulfur must be added to the charge in order to to achieve the improvements in the process according to the founding.

Table VI Results of the water addition tests

attempt
No. Addition to
H ₂ OIS ppm 2 beginning Temperature, ^U C A τ C ₅ + yield, volume percent end Δ ppm 10 516 end > 44 beginning <56.5 <-12.0 1 500 10 517 > 560 > 37 68.5 <57, O <-8.5 2 250 10 512 > 554 31 65.5 65.5 * -4.5 3 100 10 510 543 * 37 70.0 64.0 * -7.5 4th 100 0 10 514 547 * 25th 71.5 69.0 -4.5 5 0 514 539 • 28 73.5 * 66.4 -4.0 6th 542 70.4 *

Values are extrapolated to provide consistency over time.

The table shows that the presence of water in the catalytic environment for the Process is detrimental, both in terms of temperature stability and in terms of yield stability. It can also be seen that the yields in the operations in the presence of water were significantly lower than in the anhydrous operating runs, i.e. H. operation runs 5 and 6. This shows excessive generation of light gases from undesirable hydrocracking when in the Catalyst environment water is present along with hydrogen sulfide. The temperature difference values also confirm the explained instability of the reforming in the presence of water and Hydrogen sulfide.

From the values of the operating run 5 it can be seen that the exclusion of water from the catalytic environment both the temperature stability and the yield stability increased. It also shows a Comparison of runs 5 and 6 shows an increase in the yield with an increase in the sulfur content of the Feedstock by 8 parts per million; this is a very remarkable and surprising result of the method according to the invention.

In addition, the determined carbon deposited on the catalyst at the end of the test period; it was 4.07 percent by weight for the catalyst of run 5 and 4.26 percent by weight for run 6. This difference of 0.19%, brought about by the higher sulfur concentration, clearly shows the general one Trend of the method according to the invention, the rate of formation of carbonaceous deposits on the catalyst to reduce considerably.

Example 4

This example illustrates the effects of changing the amount of introduced into the reforming zone Hydrogen sulfide when carrying out the process according to the invention.

In this series of experiments, the feed, flow sheet and catalyst composition kept unchanged to clearly show the influence of introducing different amounts to point to sulfur in the reforming zone. Water was carefully excluded from the feed, and special precautions were taken to dry the system before the start of the test series taken to achieve a practically anhydrous environment.

The feed material, the flow sheet, the process conditions and the catalyst composition and preparation were the same as Example 3 except that in Run 6 the catalyst was only 0.60 percent by weight Contained chloride. Again, the operating temperature was during the test period of 144 hours Changed to maintain an enlbutanized liquid product octane number of 100 F-I clear would.

The results of the tests are shown in Table VIl compiled. In particular, they show a clear influence on the temperature stability and the yield stability over the period mentioned. It should be noted that the temperature stability represents the more important parameter with regard to the life of the catalyst, namely because of the

marked increase in the rate of carbon deposition at higher temperatures as discussed above. As can be seen from the table, shows the temperature difference between the end of the first Period and the final period show a marked decrease when the concentration increases Hydrogen sulfide is increased in the catalytic environment. Since the return hydrogen on very washed down low levels of hydrogen sulfide practically all of the sulphurous water comes from

material from the sulfur added to the feed (as indicated above, this does not always have to be to be the case).

From Table VI it can also be seen that the increase in the stability of the reaction temperature

an increase in the yield and an increase in the stability of the yield went in parallel. For example, if the concentration of sulfur in the feed increased from 2 to 1200 parts per million the temperature difference increased over the

operating period of 26 ° C at 9 from which Ausbeuledifferenz went from -4.0 to -1.9 back and, most significantly, the yield even increased by about 2 to 4 ° / _0, based on the volume of the supplied controlled feed , on. From these values goes

thus clearly shows the increased stability of the method according to the invention. Table VIl shows about it In addition, another advantageous property of the method according to the invention, namely reduction the carbon deposition while increasing the

Concentration of sulfur in the feed. From the table it can be seen that the amount of carbon in percent by weight that was on the catalyst after 144 hours of operation, when increasing

the sulfur content steadily decreased. At 2 parts per million sulfur, the coolant content was, for example, 4.26 percent by weight of the catalyst, while at 1200 parts per million sulfur the carbon content fell to 1.86%, which clearly shows this technically very advantageous feature of the process according to the invention.
The choice of the concentration made in each individual case

Tration of sulfur depends on the composition of the feed, the combination of the rest Operating conditions and the desired octane number of the product. The desired value can be for each Feed material within the limits given above by simple preliminary testing or tracking the results can be determined at the beginning of the operational run.

Table VI Results of the change in sulfur content

attempt
IMr Addition to
Q nnm Temperature, "C End I Δ Τ 26th Cj 4 — yield, percent by volume end ^Δ Carbon on the
catalyst α, ppm beginning 540 25th Beginning" 66.4 -4.0 Weight percent I. 2 514 539 27 70.4 * 69.0 -4.5 4.26 2 10 514 542 23 73.5 * 69.1 -4.4 4.08 3 50 515 537 14th 73.5 * 70.2 -4.3 4.23 4th 100 514 527 Il 74.5 * 71.6 +0.8 3.91 5 300 513 527 9 70.8 * 71.3 -2.3 2.47 6th 600 516 522 10 73.0 * 71.1 -1.9 2.20 7th 1200 513 516. 73.0 * 69.0 -2.0 1.86 8th 2400 506 71.0 1.81

* Values are extrapolated to provide consistency over time. ^a Yield values based on the volume of the feed.

Example 5

A desulphurized heavy Kuwait straight run naphtha with an initial ^{boiling point of 80 0} C, a boiling point of 173 ° C, a sulfur content of less than 1 part per million, a nitrogen content of less than 5 parts per million and a water content of 1 Parts per million was fed to a reforming zone containing an aluminum oxide, 0.75 weight percent platinum, 0.90 weight percent chlorine, and 0.10 weight percent bound sulfide catalyst. The catalyst had been prepared according to the method described in Example 1.

The reforming process was carried out at a pressure of 10.2 atmospheres, a liquid hourly space velocity of 1.5, and a hydrogen to hydrocarbon molar ratio of 7.5; the initial reactor temperature was 521 ⁰ C.

The following flow scheme was used: The feed was made with a hydrogen-rich one Gas passed over the reforming catalyst and the product was transferred to a high pressure separation zone led, part of the hydrogen-rich gas was returned from the separation zone to the reforming zone, and the liquid effluent from the separation zone was debutanized. making a high octane product incurred. Before starting up, the system was dried to 10 parts per million water in the return gas, by circulating hydrogen through a molecular sieve dryer at 27.2 atmospheres.

The feed was tert-butyl mercaptan in added in an amount that amounts to the total amount of hydrogen sulfide in the reforming zone sourced from both the feed and the recycle hydrogen at 1500 parts per million on loading.

The reactor temperature was readjusted during the entire operation so that the debutanized Product stream consistently has an octane rating. of 100 F-I was clear.

The operational run could be carried out over an extended period of time with very little change in the deactivation rate be driven. The deactivation rate was about the same as the same Feed material, but without compliance with the composition of matter in the reforming zone after the Rules of the invention, occurs when the method is carried out under a pressure of 34 atmospheres. at the method according to the invention thus achieves a stability that is otherwise only achieved with much higher Pressing is observed; in addition, an increase in the yield is achieved with the same octane number Debutanized product of 6 to 7% over the yield, which is achieved at 34 atmospheres.

Claims (6)

It is known (Austrian patent 207025, claims: French patent 1218037), in a process for reforming boiling in the gasoline range 1. Catalytic reforming process, in which the hydrocarbon fractions are hydrogen in the presence of a hydrocarbon boiling in the gasoline range and a catalyst, which is essentially charged at elevated temperature and borrowed aas an adsorbing refractory oxide and high pressure in a reforming zone with a small amount of a metal of the platinum group hydrogen-containing gas and a catalyst, consists in which a gasoline hydrocarbon fraction of a platinum group metal component and with a sulfur content of less than 0.002 weight percent heat-resistant inorganic oxide carrier , preferably not more than 0.001 Geumf, is converted, characterized by weight percent, as a charge during the total, that the reaction is fed to the reforming zone with a duration of the process pressure in the range of 5.1 to 20.4 atm in one and one hydrogen-rich gas from the effluent of the practically anhydrous environment in which the reforming zone is separated and partially recycled to the total amount of water from the feed and reforming zone that is to be introduced into the reforming zone formed from water-forming compounds The gas supplied is water less than 20 _{parts by weight per million, initially with an H 2} S content of a maximum of 35 g based on the hydrocarbon feed, per 100 m ³ and the H ₂ S concentration is, and in the presence of 10 to 3000 Ge - to gradually reduce parts by weight of sulfur per 1 million parts by weight of 20 in the recycle gas during the course of the process. It is thus about the loading process. an addition of hydrogen sulfide during the start-up 2. The method according to claim 1, characterized in period, then the sulfur concentration is continued, that a hydrocarbon charge is continuously lowered. It is pressed in the area kung, the oxygen-containing compounds from 20 to 60 at, d. H. in the usual pressure range of in an amount that less than 5 weight as reforming worked. Special regulations parts per million of water, based on the feed, over a certain water content to be maintained arise and about 10 to about 1000 parts by weight in the implementation are not given. per million calculated as equivalent sulfur to It is also known (British patent 1021412, contains sulfur-containing compounds. French patent specification 1336801), at the 3. The method according to claim 1 or 2, characterized in 30 position of aromatic hydrocarbons characterized in that a light naphtha with light hydrocarbon feedstocks, the mineinem End boiling point of about 149 ° C used containing at least 50 percent by volume paraffins in one and to operate at a pressure in the range of about 5.1 predried reaction system, wherein works until about 8.5 at. the water content of the 4. The method according to any one of claims 1 to 3, 35 occurring total charge at all times during characterized in that at least the introduction of hydrocarbons is below 100% Part of the sulfur in the hydrogen-containing lum part per million, based on the total charge, Gas and / or independently of other material in the vapor phase, and the water content of the from the flow into the reforming zone. Reaction system drained effluent to all 5. The method according to any one of claims 1 to 4, 40 times of hydrocarbon introduction below characterized in that at least 100 parts by volume per million, based on the total a part of the sulfur of the reforming zone in the outflow, in the vapor phase, should be. A BeForm a reducible sulfur-containing limitation of the water content to any binding feeds. special values well below 100 parts by volume 6. The method according to any one of claims 1 to 5, 45 per million is not prescribed. It should be characterized in that the reaction pressure of 14 to 49 atmospheres and preferably 21 to an hourly Raumströmungsgeschwindig- 35 atmospheres, and with all the liquid from about 0.5 to about 10 and play come pressures of 25 to 35 atm at a temperature in the range from about 427 to turning, ie in the usual pressure range of about 593 ° C using a molar reforming. The sulfur content of the total hydrogen to hydrocarbon feed container should preferably be kept below 25 weight feed of about 1 to about 15 with recycle (parts per million, an intentional introduction of at least a portion of that contained in the effluent from the sulfur feed to the reaction system in the be reforming zone hydrogen gas to agreed amounts is foreign to the known process, the reforming is carried out. _55. Further, an operation has become known (USA.-Patent 3,155,605), in which a heavy gasoline in two separate reforming facilities reformed under different conditions, where the higher-boiling heavy gasoline content is primarily from sulfur and only the lower-boiling component The invention relates to a catalytic reforming heavy gasoline component in the presence of added in which a sulfur boiling in the gasoline range is reformed. There is a special one Uhlenhydrogen loading at elevated temperature. Steam treatment of the catalyst for the deep fr and increased pressure is provided in a reforming zone with boiling heavy gasoline fraction. It should be at iem hydrogen-containing gas and a catalyst, 65 the usual reforming conditions are used, r is a platinum group metal component and one being in a very wide range of pressures from 3.5 to corrosion-resistant inorganic oxide carriers, 70 atmospheres are mentioned, but is used in the examples is set. consistently with conventional pressures of approx