RU2108153C1 - Catalytic system for reforming of hydrocarbon-containing raw material and reforming process - Google Patents

Abstract

FIELD: petroleum processing and catalysts. SUBSTANCE: sulfur sensitive reforming catalyst is converted into less sulfur sensitive one owing to utilization of catalytic system including physical mixture of such catalyst with sulfur-absorption agent capable of capturing small amounts of sulfur from hydrocarbon raw material. Advantageously, mixture includes sulfur sensitive reforming catalyst protected against sulfur deactivation by manganese oxide absorbent. Catalyst of invention exhibits marked advantages in catalytic reforming process as compared to those processes involving potassium form of L-zeolite component. EFFECT: enhanced formation of aromatic hydrocarbons and prolonged lifetime of catalyst. 4 cl, 2 tbl

Description

 The invention relates to the catalytic reforming of hydrocarbons boiling in the gasoline range, which is an important industrial process carried out at almost every significant refinery in the world with the aim of producing aromatic intermediates for the petrochemical industry or gasoline components having high anti-knock resistance in the engine. Demand for aromatic compounds is growing faster than providing raw materials for aromatics production.

 Moreover, the widespread removal of antiknock lead-containing additives from gasoline and the growing demand for highly efficient internal combustion engines cause an increase in the required antiknock resistance of the gasoline component, which is measured by the octane number of gasoline.

 Therefore, the catalytic reforming unit should be operated more efficiently in a more stringent mode in order to satisfy these increasing demands for aromatic compounds and high-octane gasoline. This trend creates the need for more efficient reforming processes and catalysts.

 The effectiveness of reforming catalysts, including non-acid L-zeolite and a platinum group metal, for dehydrocyclization of paraffins is well known in the art.

 The use of these reforming catalysts to produce aromatic hydrocarbons from paraffin raffinates, as well as from heavy gasoline, has been described.

 The increased sensitivity of these selective catalysts to sulfur is also known. It is believed that the extreme unexpected sensitivity to sulfur of these reforming catalysts is the main reason for the extended development period and slow commercialization of this dehydrocyclization technology.

 A known reforming catalyst containing zeolite L in potassium and / or barium form, a group VIII metal in an amount of 0.3-2.5 wt.%, Rhenium and an inorganic oxide selected from the group consisting of silicon oxide, alumina, magnesium oxide, zirconium oxide and others

 The operation of the plants and technological costs will become more favorable as a result of new methods for solving the sulfur problem such as those provided by the catalytic system of the invention.

 Desulphurization of gasoline feedstocks for the reforming process of sulfur sorbents is widely disclosed. US patents NN 4225417 and 4329220 describe a reforming process in which sulfur is removed from reforming feedstocks using a composition containing manganese.

 Preferably, the feed is hydrotreated and the sulfur content in these inventions decreases below 1 ppm. U.S. Patent Nos. 4,534,943 and 4,575,415, respectively, describe a device and method for removing residual sulfur from reforming feedstocks using parallel absorbers for continuous operation; in ideal mode, sulfur is removed to below 0.1 ppm.

 US Pat. No. 4,456,527 describes the reforming of a hydrocarbon feed having a sulfur content as low as 50 ppm, with a catalyst including a wide pore zeolite and a Group VIII metal.

 A wide range of sulfur removal options has been described in order to lower the sulfur content of hydrocarbons below 500 ppm.

 A US patent is devoted to a method for removing residual sulfur from a hydrotreated gasoline feedstock, which comprises contacting the feedstock with a sulfur-less reforming catalyst, a sulfur sorbent, and a highly selective reforming catalyst.

 US Pat. No. 5,059,304 discloses a physical mixture of a conventional catalyst — platinum on alumina — and a sulfur sorbent containing a metal of group 1A or IIA for the purpose of desulphurizing gasoline feedstocks for further processing in a reforming unit, as well as a reforming process involving contacting the crude feedstock under conditions reforming with a catalytic system containing a reforming catalyst and a sulfur-containing absorber.

 US Pat. No. 4,954,245 discloses a platinum / L-zeolite catalyst having enhanced sulfur resistance by incorporating rhenium into it.

 However, none of the above references anticipated or proposed a catalytic system comprising a physical mixture of a sulfur-sensitive reforming catalyst and a sulfur sorbent.

 The aim of the invention is to develop a catalytic system for the catalytic reforming process, effective for dehydrocyclization of paraffins in the presence of small amounts of sulfur with high stability of the catalyst.

 The aim of the invention is to eliminate the deactivation of sulfur reforming catalyst having an unusual intolerance to sulfur.

 This invention is based on the fact that a reforming catalyst system using a catalyst system comprising a physical mixture of a sulfur-sensitive catalyst and a sulfur sorbent is surprisingly effective in absorbing sulfur in order to avoid deactivation of the sulfur-sensitive catalyst.

 A wide embodiment of the invention is a sulfur-resistant catalytic system comprising a physical mixture of a sulfur-sensitive reforming catalyst containing a platinum group metal and a sulfur sorbent containing a metal oxide selective for sulfur adsorption.

 An example of the embodiment of this catalytic system is a physical mixture of a platinum-containing reforming catalyst and manganese oxide sulfur sorbent.

 In a preferred embodiment, such a catalytic reforming system comprises a potassium form of L-zeolite.

 Another embodiment of the invention is a catalytic reforming process that utilizes at least in the initial conversion zone a catalyst system comprising a physical mixture of a sulfur sensitive reforming catalyst.

 The mutual combined action of the catalyst and the sulfur sorbent provides excellent results in achieving favorable yields with a high degree of catalyst utilization under dehydrocyclization conditions using a sulfur sensitive catalyst.

 The first particles of the conversion catalyst and the second particles of sulfur sorbent are obtained as described below. Preferably, the first particles are substantially free of sulfur sorbent, and the second particles are substantially free of a conversion catalyst, and these first and second particles are mechanically mixed in order to provide a catalyst system of the invention.

 These particles can be thoroughly mixed using known techniques, such as grinding to a well-mixed physical mixture.

 The mass ratio of the conversion catalyst to the sulfur sorbent mainly depends on the sulfur content in the feed and can vary from about 1:10 to 10: 1.

Preferably, a sample of simultaneously mixed batch of 100 cm ³ will not differ in the percentage of each component of the mixture in another batch by more than 10%.

 Although the first and second particles may have similar size and shape, preferably the particles have different sizes and / or densities to facilitate separation for the purpose of regeneration or recovery and their subsequent use in hydrocarbon processing.

 The conversion or reforming catalyst comprises a composition of a metal component of hydrogenation — dehydrogenation on a refractory carrier.

 This catalyst is effective for converting small amounts of sulfur in a hydrocarbon feed during reforming to hydrogen sulfide, which can then be readily absorbed by sorption to avoid deactivation of the sulfur sensitive catalyst.

 This catalyst will be able to withstand occasionally up to 10 ppm. sulfur in raw materials with almost constant activity.

 This conversion catalyst also preferably carries out to some extent the dehydrogenation of naphthenes in the feed and may contain acid sites that carry out isomerization, cracking and dehydrocyclization.

 The refractory support of the transformation catalyst should be a porous, adsorption material with a high surface area, which is uniform in composition without a gradient in the composition of the particles included in this composition.

The present invention covers refractory media containing one or more materials from:
1) refractory inorganic oxides such as aluminum oxides, silicon dioxide, titanium dioxide, magnesium oxide, zirconia, chromium oxide, thorium, boron, or a mixture thereof;
2) prepared synthetically or naturally occurring clay and silicates that can be treated with acid;
3) crystalline zeolite luminosilicates of either natural origin or synthetically prepared, such as FAU, MEL, MET, MOR, MTW (IUPAC Zeolite Nomenclature Commission), in hydrogen form or in a form that has been exchanged with metal cations;
4) spinels, such as magnesium - aluminum, iron - aluminum, zinc - aluminum, calcium - aluminum;
5) combinations of materials from one or more of these groups.

 A preferred refractory support for the conversion catalyst is alumina, with gamma or theta forms of alumina being particularly preferred.

 The best results were obtained with Ziegler Alumina described in US Pat. No. 2,892,858, which is currently available from Vista Chemical Company under the Katapal trademark or from Condea Chemie GmbH under the Pural trademark.

 Ziegler alumina is a very high purity pseudoboehmite, which, after calcination at high temperature, has been shown to form gamma - alumina of high purity.

It is particularly preferred that the refractory inorganic oxide comprise substantially pure Ziegler alumina having an apparent bulk density of 0.6-1 g / cm ³ and a surface area of 150-280 m ² / g (especially 185-235 m ² / g) and pore volume 0.3-0.8 cm ³ / g

 Alumina powder can be formed into any form of carrier material that is known to those skilled in the art, such as spheres, extrudates, rods, pills, granules, granules or tablets.

 Spherical particles can be formed by converting the alumina powder to an alumina sol by reacting with a suitable peptizing acid and water and dropping a mixture of the obtained sol and gelling agent into an oil bath to form spherical alumina gel particles, as described in US Pat. No. 2,620,314, c subsequent aging, drying and calcination stage.

A preferred form of extrudate is best prepared by mixing alumina powder with water and suitable peptizing agents such as nitric acid, acetic acid, aluminum nitrate and the like. materials in order to obtain an extrudable cake having annealing loss (PP) at 500 ^° C. 45 - 65 wt.%.

 The resulting cake is extruded through a template of a suitable shape and size to obtain extrudable particles that are dried and calcined by known methods.

 Alternatively, spherical particles can be formed from extrudates by rotating the extrudate particles on a rotary disk.

 An essential component of the sulfur-sensitive conversion catalyst is one or more platinum group metals, with the platinum component being preferred.

 Inside the catalyst, platinum may be in the form of a compound, such as an oxide, sulfide, halide or oxyhalide, in chemical combination with one or more ingredients of the catalyst composition or in the form of an elemental metal.

 The best results were obtained when almost all platinum is in a reduced state in the catalytic composition.

 The platinum component typically comprises about 0.01-2 wt.% Of the catalyst composition, preferably 0.05-1 wt.%, Based on the platinum element.

 Also included in the scope of protection of the invention is that the catalyst may contain metal modifiers, which are known to modify the effect of the preferably platinum component.

 Such metal modifiers may include Group IVA (14) metals of the Periodic Table (Cotton and Wilkinson Advanced Chemistry of Organic Chemistry, J. Wiley and Sons, 5-t, 1988), other Group VIII metals (8-10), rhenium, indium, gallium, zinc, uranium, dysprosium, thallium, and mixtures thereof.

 Catalytically effective amounts of such metal modifiers can be introduced into the catalyst by any methods known in the art.

 The conversion catalyst in some cases may contain a halogen component. This halogen component may be either fluorine, chlorine, or iodine, or mixtures thereof. Chlorine is a preferred halogen component.

 Typically, the halogen component is present in a state bound to an inorganic oxide carrier. The halogen component is preferably well dispersed throughout the catalyst and may comprise from more than 0.2 to 15 wt.% Based on the element based on the weight of the finished catalyst.

 A preferred component of the conversion catalyst is a non-acidic, large pore molecular sieve.

или более и включают те сита, которые охарактеризованы как AF1, FAU или LTL - структурного типа по номенклатуре цеолитов Комиссии ИЮПАК.Suitable molecular sieves typically have the same pore mouths or a pore size of approximately

or more and include those sieves that are characterized as AF1, FAU or LTL - structural type according to the nomenclature of zeolites of the IUPAC Commission.

 An LTL structure is preferred, wherein the self-sensitive catalyst is optimally a reforming catalyst comprising L-zeolite, an alkali metal component and a platinum group metal component.

 It is essential that the L - zeolite be non-acidic, since the acidity of the zeolite reduces its selectivity for aromatic hydrocarbons in the final catalyst.

 In order to be non-acidic, zeolite has almost all cation-exchange centers occupied by non-hydrogen particles.

 Preferably, cations occupying exchangeable cationic centers will include one or more alkali metals, although other particles may also be present.

 A particularly preferred non-acidic L-zeolite is the potassium form of the L-zeolite.

 It is necessary that the L - zeolite be arranged with a binder in order to provide a convenient form for using the catalyst of the invention. It follows from the technical field that any refractory inorganic oxide binder is suitable.

Preferred binders of the invention are one or more of silicon dioxide, aluminum oxide or magnesium
Silica is particularly preferred and particularly excellent results are obtained using a synthetic white silica powder precipitated as ultrafine spherical particles from an aqueous solution.

The silica binder is preferably non-acidic, containing less than 0.3 wt.% Sulfate salts, and has a BET surface area of 120-160 m ² / g.

 L - zeolite and a binder can be combined with the formation of the desired form of the catalyst by any method known in the art.

 For example, the potassium form of L - zeolite and amorphous silica can be mixed as a homogeneous powder mixture before the introduction of the peptizing agent. An aqueous solution including sodium hydroxide is added in order to obtain a cake suitable for extrusion.

 This cake may preferably have a moisture content of 30-50 wt.% In order to form extrudates having acceptable integrity in order to withstand direct calcination.

 The resulting dough is extruded through a template of an appropriate shape and size to form extrudate particles that are dried and calcined by known methods.

 Alternatively, spherical particles can be obtained by the methods described above for a conversion catalyst in a physical mixture.

 The alkaline metal component is an essential component of a sulfur sensitive reforming catalyst when it contains L - zeolite.

 One or more alkali metals, including lithium, sodium, potassium, rubidium, cesium and mixtures thereof, may be used, with potassium being preferred. In the best way, a metal can occupy substantially all cationic centers capable of exchange in a non-acid L-zeolite.

 An alkali metal deposited on the surface may also be present, as described in US Pat. No. 4,691,906, incorporated herein by reference.

Typically, the sulfur-sensitive reforming catalyst can be dried at a temperature of 100 - 320 ^o C for 0.5 to 24 hours, followed by oxidation at a temperature of 300 - 550 ^o C (preferably 350 ^o C) in an atmosphere of air for 0.5 to 10 h

Preferably, the oxidized catalyst undergoes a reduction step in the absence of water at a temperature of about 300-550 ^° C (preferably 350 ^° C) for 0.5-10 hours or more.

 The duration of the reduction step should only be such as to ensure the reduction of platinum and to avoid preliminary deactivation of the catalyst, and this step can be carried out on site as part of the start-up of the plant if a dry atmosphere is maintained.

 Further details of the preparation and activation of embodiments of the sulfur-sensitive reforming catalyst are disclosed, for example, in US Pat. Nos. 4,691,906 and 4,822,762, which are incorporated herein by reference.

 In this embodiment, which is described below, the catalyst also contains an alkali metal component, and preferably the binder is non-acidic amorphous silica.

The final conversion catalyst, which is formed in the first particles to prepare the physical mixture of the invention, can usually be dried at a temperature of 100 - 320 ^o C for 0.5 to 24 hours, followed by oxidation at a temperature of 300 - 550 ^o C in air for 0 5 - 10 hours

Preferably, the oxidized catalyst is reduced in the absence of water at a temperature of about 300-550 ^° C. for 0.5 to 10 hours or more.

 The sulfur sensitivity of the conversion catalyst is measured as an index of sulfur sensitivity or SDI. This PSI index is a measure of the effect of sulfur in hydrocarbon feedstocks on the catalytic reforming process, on the characteristics of the catalyst, in particular on the activity of the catalyst.

 IES is measured as the relative rate of deactivation in the presence and absence of sulfur in the feedstock for processing in order to achieve a certain conversion under given operating conditions.

 The decontamination rate is expressed as the rate of increase of the operating temperature per unit time or (which gives equivalent results) in order to maintain a given conversion, usually the deactivation rate is measured from the time of the start of work, when the unit reaches a stationary state, until the end of the experiment, when deactivation accelerates or work reaches an excess level, which is known from the prior art.

 The conversion can be determined on the basis of the octane number of the product, the yield of a particular product, or as here by the consumption of raw materials.

In the proposed application, the decontamination rate at a typical sulfur content in the feed is 0.4 ppm. (400 h / bn), compared with the decontamination rate for raw materials not containing sulfur:
IES = D _s / D _o ,
where D _c is the decontamination rate for raw materials from 0.4 ppm. sulfur;
D _about - deactivation rate for raw materials that do not contain sulfur.

 In this case, "sulfur free" means less than 50 pb. or, more typically, less than 20 ppm. sulfur in raw materials.

 Being a relative value of the PPI, it is assumed that it will not show significant changes with varying operating conditions.

In the proposed application, the main working conditions for determining the ICE are: pressure 456 kPa (4.5 atm), fluid flow rate (volumetric) equal to 2 h ^-1 , the molar ratio of hydrogen / hydrocarbon = 3 and the conversion of hexanes and heavier hydrocarbons in the raffinate after extraction aromatic hydrocarbons as defined in the examples.

 Other conditions are indicated in the examples. The operating conditions are changed in order to achieve the desired conversion, the deactivation rate being determined by the rate of temperature increase to maintain the conversion, as indicated above.

 The sulfur-sensitive catalyst has an ISI value of greater than 1.2 and preferably at least about 2.0. Catalysts with an ICI of about three or more are particularly advantageously protected against gray deactivation by the method of the invention.

 It is significant that the sulfur absorber of the present invention is not only effective for removing small amounts of sulfur compounds from hydrocarbon streams under the operating conditions of the conversion catalyst, but also that this sorbent is compatible with the conversion catalyst in order to maintain the activity of the catalyst.

 The sulfur absorber includes a metal oxide, preferably selected from metal oxides having an atomic number between 19 and 30 inclusive, these metals, in particular potassium, calcium, vanadium, manganese, nickel, copper and zinc, are known to be effective in removing sulfur in others circumstances.

Preferably, the sorbent includes a manganese component. It has been found that manganese oxide provides a better protection to the reforming catalyst than zinc oxide in the prior art, as suggested because of possible contamination of the combined reforming catalyst. Manganese oxides include MnO, Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ , MnO ₃ and Mn ₂ O ₇ .

 A preferred manganese oxide is MnO (manganese oxide). The manganese component may be in a composition with an appropriate binder, such as clay, graphite or inorganic oxides, including one or more oxides: alumina, silica and zirconia, magnesium, chromium or boron oxide, in order to provide the second part of the physical catalytic mixture system.

 Preferably, the manganese component is unbound and consists essentially of manganese oxide.

 Even more preferably, the manganese component consists essentially of MnO, which has shown excellent sulfur removal results and has shown an appropriate particle strength without a binder for the second type of particles of the present invention.

 As an alternative embodiment of the invention, the physical mixture of the conversion catalyst and the sulfur scavenger is contained in the same catalyst particle.

 In this embodiment, the catalyst and the absorber can be ground or milled together or separately to form particles of a suitable size, preferably less than 100 microns, and these particles are applied to a suitable matrix. Preferably, the matrix is selected from the inorganic oxides described above.

 The physical mixture of the conversion catalyst and the sulfur scavenger is placed in a fixed bed reactor or in a moving bed reactor, whereby the catalyst can be continuously removed and added.

These alternatives are associated with catalyst regeneration options that are known to one of ordinary skill in the art, such as:
1) a semi-regenerative installation containing fixed bed reactors in which the stiffness of the mode is maintained by increasing the temperature, periodically stopping the installation for regeneration and reactivation of the catalyst:
2) an interruptible reactor installation in which individual fixed-bed reactors are sequentially isolated using a variety of devices when the catalyst becomes deactivated and the catalyst in the isolated reactor is regenerated and reactivated while other reactors remain in operation;
3) continuous regeneration of the catalyst withdrawn from the reactor with a moving bed, with reactivation and the introduction of reactivated catalyst, which allows to increase the stiffness of the regime, maintaining high catalytic activity due to regeneration cycles of several days;
4) a hybrid system with semi-regenerative and continuous-regenerative support in the same installation.

 A preferred embodiment of the invention are fixed bed reactors in a semi-regenerative installation.

 The proposed catalytic system can be used in the process of conversion of hydrocarbons and preferably in the reforming process, which also uses a catalyst with a high sensitivity to sulfur.

 The catalytic system may contain in a single reactor or in multiple reactors with a prior art system for providing appropriate temperatures at the inlet to individual reactors.

 The feed can be contacted with the catalyst system in each respective reactor with the input method of upward, downward or radial flows.

 Since the preferred reforming process is carried out at relatively low pressure, the radial feed method is advantageous due to the low pressure drop in the radial flow reactor.

 The operating conditions used in the method of the present invention include a pressure of 101.3-6028 kPa (1-60 atm), with a range of 101.3-2026 kPa (1-20 atm) being preferred and a pressure below 10 atm being particularly preferred.

 Free hydrogen is preferably fed into the process in an amount that is sufficient to correspond to a ratio of 0.1 to 10 mol of hydrogen per 1 mol of hydrocarbon feed.

 The term “free hydrogen” means molecular hydrogen not included in hydrocarbons or other compounds.

Preliminary, the reaction is carried out in the absence of added halogen. The volume of the physical mixture of the catalyst and the absorber corresponds to a volumetric flow rate of 0.5 - 40 h ^-1 . The operating temperature is usually in the range 260 - 560 ^o C.

 This temperature is selected to convert sulfur compounds in the feed to hydrogen sulfide in order to prevent contact of sulfur with a subsequent sulfur-sensitive catalyst.

 The nature of the hydrocarbon in the feed also influences the temperature choice, since usually naphthenic hydrocarbons are dehydrogenated on the first reforming catalyst with a concomitant decrease in temperature across the catalyst bed due to the endothermic heat of the reaction.

 Typically, the temperature is slowly raised during each period of operation in order to compensate for the inevitable deactivation of the catalyst.

 The hydrocarbon feed may include paraffins and naphthenes and may include aromatic hydrocarbons and small amounts of olefinic hydrocarbons, which are preferably boiled off in the gasoline range.

 Raw materials such as straight-run gasolines, natural gasoline, synthetic naphtha, thermal gasoline, catalytic gasoline, partially reformed gasolines or raffinates after extraction of aromatic hydrocarbons can be used.

The boiling range can be the same as the full boiling range of gasoline, having an initial boiling point of usually 40 - 80 ^o C and a boiling point of 160 - 210 ^o C, or the raw material can boil in a narrower range with a lower boiling point.

Light paraffinic feedstocks, such as gasoline oils from the Middle East, having a boiling point of between 100 and 160 ^° C, are preferred due to the process’s specific ability to dehydrocyclize paraffins to aromatic hydrocarbons.

The raffinates after extraction of aromatic hydrocarbons, including mainly low-value C ₆ -C ₈ paraffins, which can be converted into valuable BTX aromatic hydrocarbons - gasoline, toluene and xylene, are a particularly preferred raw material.

 The hydrocarbon feed of the proposed method contains small amounts of sulfur compounds, usually less than 10 ppm per element.

 Preferably, the hydrocarbon feed is prepared from contaminated feed using a conventional pretreatment step, such as hydrotreatment, hydrotreating, or hydrotesting, in order to convert contaminants such as sulfur, nitrogen, and oxygen containing compounds into hydrogen sulfide, ammonia, and water, respectively, which can then be separated from hydrocarbons by fractionation.

 Preferably, a catalyst known in the art and comprising an inorganic oxide support and metals selected from groups VIB (6) and VIII (9-10) of the Periodic Table can be used at this pretreatment step.

 Alternatively or in addition to conventional hydrotreating, the pretreatment step may include contact with absorbers that can remove sulfur and other contaminants.

 These scavengers may include, but are not limited to, zinc oxide, iron chips, finely divided sodium, finely divided alumina, activated carbons and molecular sieves; excellent results are obtained with a nickel-on-alumina sorbent.

 Preferably, the pretreatment step will provide a catalytic reforming system with a hydrocarbon feed having a low sulfur content, which is described in the prior art as the desired feed for reforming, for example 1 to 0.1 ppm. (100 ppm); for modern pretreatment plants, sulfur levels are 0.5 - 0.15 ppm.

 A hydrocarbon product after processing hydrocarbon feeds on a real catalyst system will usually be substantially sulfur free. Sulfur-free means a sulfur content of less than 20 ppm. (ppb) and more preferably than 14 ppm.

 In another aspect, sulfur free means that sulfur is not detected. Test reproducibility of American National Standard ASTM D 4045-87 is 20 ppm. with a sulfur content of 0.02 ppm (20 ppm), and not containing sulfur in accordance with this test, will therefore mean less than 20 ppm. sulfur.

 However, it is believed that in one laboratory test of a number of similar samples, differences can be detected at lower sulfur contents, for example, 10 μg / ml or 14 ppm. sulfur.

 The catalyst system can be used in a first conversion zone containing a physical mixture of a sulfur-sensitive conversion catalyst and a sulfur scavenger, with one or more subsequent conversion zones that contain only a sulfur-sensitive catalyst.

 This first and one or more subsequent conversion zones may be contained in separate reactors or in the same reactor.

 It is within the scope of the invention that the catalyst system is used in a reactor system comprising a plurality of series reactors, of which two or more comprise both a first conversion zone comprising a catalyst system and a second conversion zone containing only a sulfur-sensitive conversion catalyst.

 Multiple reactors, each containing a physical mixture as well as a sulfur-sensitive catalyst, can be effective when sulfur contaminated equipment can be released into raw materials entering the reactors, or sulfur is introduced into the raw materials entering the reactor.

 For example, sulfur, comprising about 0.1 ppm. relative to raw materials, can be introduced in order to passivate the surface of equipment, such as heater pipes.

 The second and subsequent conversion zones operate at a pressure consistent with the pressure in the first transformation zone described above, 101.3-6078 kPa (1-60 atm) and preferably 101.3-2026 kPa (1-20 atm).

Excellent results were obtained at operating pressures lower than 1013 kPa (10 atm). The molar ratio of free hydrogen / hydrocarbon is about 0.1 to 10 mol of H ₂ per 1 mol of hydrocarbon from the first transformation zone.

Preferably, the reaction is carried out in the absence of added halogen. The space velocity with respect to the volume of the sulfur-sensitive reforming catalyst is about 0.2-10 h ^-1 .

The operating temperature is about 400-560 ^° C. and can be controlled independently of the temperature in the first transformation zone, as described above.

 The reactants are preferably contacted with the physical mixture and sequentially with a sulfur-sensitive downstream catalyst, this invention including the fact that steam, liquid, or heterophase flow is introduced between the zones in order to control the temperature of the reactants at the inlet to the sulfur-sensitive catalyst bed.

 Using a technique and equipment known in the art, an aromatic hydrocarbon-containing stream exiting the second conversion zone typically passes through a cooled separation zone.

In this separation zone, usually maintained at a temperature of about 0 - 65 ^° C., the hydrogen enriched gas is separated from the liquid phase.

 Then, the resulting hydrogen enriched stream can be recycled back to the first conversion zone using a suitable compression device.

 The liquid phase is usually removed from the separation zone and processed in a fractionation system in order to adjust the concentration of light hydrocarbons and obtain a reformate containing aromatic hydrocarbons.

 Comparative Example 1. The sulfur sensitivity index of the prior art reforming catalyst is determined. The extruded reforming catalyst — chlorinated alumina platinum rhenium used in this test was designated catalyst A, containing 0.25 wt.% Platinum and 0.40 wt.% Rhenium.

The sulfur sensitivity index of this catalyst was determined by processing hydrotreated naphtha in two comparative experiments in pilot plants, in one of which naphtha was practically sulfur free and in the second naphtha was sulfurized with thiophene additive to obtain a sulfur concentration of about 0.4 parts by weight. / million (ppm) in raw materials. Gasoline feedstock has the following characteristics:
Specific Gravity - 0.746
ASTM D-86 ^o C standard:
The beginning of the boil - 85
50% - 134
The end of the boil - 193
Naphtha was loaded into the reactor, feeding it with a flow from top to bottom, under the following operating conditions:
Pressure, KPa - 1520
Hydrogen / hydrocarbon, mol / mol - 2
The volumetric rate of fluid supply, h ^-1 . - 2.5
The target research octane was 98.0 without additives. These tests were carried out to a final test temperature of approximately 535 ^o C.

 The sulfur sensitivity index was calculated based on the relative decontamination rates with the addition of 0.4 ppm. sulfur in raw materials and without the addition of sulfur.

Within the accuracy of the test, the decontamination rates were the same for both types of raw materials and amounted to 3 ^o C days, and therefore the index of sensitivity to sulfur of catalyst A is 1.0. Catalyst A is thus a prior art reference catalyst with respect to the sulfur sensitivity index.

 Comparative example 2. Determine the index of sensitivity to sulfur of the second non-zeolitic reforming catalyst. The spherical reforming catalyst, platinum-rhenium on chlorinated alumina, used in this test, was designated as catalyst B, it contained 0.22 wt.% Platinum and 0.44 wt.% Rhenium.

 The sulfur sensitivity index of this catalyst was determined by processing hydrotreated naphtha in two series of comparative experiments in pilot plants, in one of which naphtha contained almost no sulfur (Experiments B-1 and B-1 ') and in the second naphtha was sulfurized with thiophene additive ( Experiments B-2 and B-2 ') to obtain a sulfur concentration of about 0.4 parts by weight per million. (ppm) in raw materials. Gasoline feedstock differed in each series of experiments and had the following characteristics (see table. 1).

 Naphtha was loaded into the reactor, feeding it with a flow from top to bottom, under the following operating conditions: (see table. 2).

The target research octane was 98.0 without additives. These tests were carried out to a final test temperature of approximately 535 ^o C.

The Sulfur Sensitivity Index (SIS) was calculated based on the relative decontamination rates with the addition of 0.4 ppm. sulfur in raw materials without additives of sulfur. The following results were obtained:
B-1 - 1.6 ^o C / day
B-2 - 2.5 ^o C / day
IHD = B-2 / B-1 - 1.6
B-1 '- 0.85 ^o C / day
B-2 '- 1.1 ^o C / day
IHD = B-2 '/ B-1' - 1.3
Comparative Example 3. A sulfur sensitivity index of a reforming catalyst with a high sensitivity to sulfur was determined. The silica-bound L-zeolite (potassium form) reforming catalyst used in this test was designated Catalyst C and contained 0.82 wt.% Platinum.

The sulfur sensitivity index of this catalyst was determined by processing hydrotreated naphtha in two comparative experiments on pilot plants, in one of which naphtha contained almost no sulfur (experiment C-1) and in the second naphtha was sulfurized with thiophene additive (experiment C-2), to get a sulfur concentration of about 0.4 wt. ppm (ppm) in raw materials. Gasoline feedstocks had the following additional characteristics:
Specific Gravity - 0.6896
ASTM D-86, C
The beginning of the boil - 70
50% - 86
The end of the boil - 138
Naphtha was loaded into the reactor, feeding it from top to bottom under the following operating conditions:
Pressure, KPa - 456
Hydrogen / hydrocarbon, mol / mol - 3
The volumetric rate of fluid supply, h ^-1 - 2
These tests were carried out to a final test temperature of approximately 480 ^o C.

The Sulfur Sensitivity Index (SIS) was calculated based on the relative decontamination rates with the addition of 0.4 ppm. sulfur in raw materials and without the addition of sulfur. The following results were obtained:
C-1 - 0.3 ^o C / day
C-2 - 4.0 ^o C / day
SDI = C-2 / C-1 - 13
Comparative example 4. The advantage of the catalytic system of the invention compared with the prior art is illustrated by comparative processing of 1000 metric tons / day of naphtha containing 0.5 wt. ppm sulfur in the form of thiophene.

Equal volumes of the conversion catalyst and the sulfur scavenger were charged into the reactors in order to obtain a volumetric feed rate of 5 h ^-1 both to illustrate the invention and in the comparative case of the prior art.

The catalyst and the absorber were physically mixed to illustrate the invention, the conversion catalyst being loaded on top of the sulfur absorber to illustrate the prior art. The relative amounts of catalyst and absorber are shown below:
4.8 t conversion catalyst
Sulfur absorber - 9.6 t
The conversion catalyst was a sulfur-sensitive reforming catalyst described above, the disadvantage of which is a rapid decrease in dehydrocycling ability in the presence of sulfur, but it retains the ability to process sulfur within its sulfur capacity, which is about 0.1 wt.%.

 The conversion catalyst contained platinum on silica-bound L-zeolite in potassium form. As shown in comparative example 3, it had a sulfur sensitivity index of about 13.

 The sulfur absorber was almost pure manganese oxide, having a sulfur capacity of about 5 wt.%.

The duration of work until the full sulfur load is achieved illustrates the advantage of the invention:
Invention - 970 days
The prior art - 9.6 suto

Claims (4)

 1. The catalytic system for the reforming of hydrocarbons, including a sulfur-sensitive reforming catalyst containing a non-acidic potassium form of L-zeolite, a platinum group metal and a refractory inorganic carrier - alumina and / or silicon dioxide, characterized in that the catalytic composition further includes a sulfur-containing absorber based on manganese oxide, wherein the catalyst composition is a physical mixture of a sulfur-sensitive reforming catalyst and a sulfur absorber in a mass ratio of 1: 10 to 10: 1.  2. The system according to claim 1, characterized in that it contains a physical mixture of a sulfur-sensitive reforming catalyst and a sulfur absorber on the same catalyst particle.  3. A method of reforming a hydrocarbon feedstock, comprising contacting the petroleum feedstock under reforming conditions with a catalyst system containing a reforming catalyst and a sulfur-containing absorber, characterized in that a catalyst system is used that is a physical mixture of a sulfur-sensitive reforming catalyst containing a non-acid potassium form of L-zeolite , a platinum group metal and a refractory inorganic carrier - aluminum oxide and / or silicon dioxide, and a sulfur-based absorber based ksida manganese in a weight ratio of 1: 10 - 10: 1.  4. The method according to p. 3, characterized in that the use of petroleum feedstocks with a sulfur content of less than about 10 parts by weight per million.

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