JP2547968B2 - Sulfur-resistant reforming catalyst system containing sulfur-sensitive components and hydrocarbon reforming process using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sulfur-resistant reforming catalyst containing a component susceptible to sulfur and a method for reforming hydrocarbons using the catalyst.

[0002]

BACKGROUND OF THE INVENTION Catalytic reforming of hydrocarbon feedstocks of gasolines is an important commercial process, which processes aromatic intermediates for the petrochemical industry, or gasoline components with high resistance to engine knock. Manufactured at most important oil refining facilities around the world for production. The demand for aromatics is growing faster than the supply of raw materials for aromatics production. Furthermore, the removal of lead anti-knock conversion agents from gasoline over a wide range, and the increasing demand for high-performance internal combustion engines, requires improvement in knock resistance of gasoline components, which is measured by "octane number". Therefore, the catalytic reformer is
In order to meet the demands for these aromatics and gasoline-octane, it is necessary to operate more efficiently under more severe conditions. This trend calls for more effective reforming processes and catalysts.

Catalytic reforming is usually applied to raw materials containing a large amount of paraffin and naphthenic hydrocarbons, and dehydrogenation of naphthenes to aromatic compounds, dehydrocyclization of paraffins, paraffins and naphthenes It is carried out through various reactions such as isomerization, deacrylicization of acrylic aromatic compounds, hydrocracking of paraffins to light hydrocarbons, and formation of coke deposited on the catalyst. The increasing need for aromatics and gasoline-octane numbers has increased interest in paraffin dehydrocyclization reactions which are less thermodynamically and kinetic energy less favorable than conventional aromatization reforming. . There is a strong demand to make the dehydrocyclization reaction more popular than other hydrocracking reactions to increase the desired product yield from catalytic reforming by minimizing coke formation. The effectiveness of catalytic reforming composed of non-acidic L-zeolites and platinum group metals for dehydrocyclization of paraffins is well known in the prior art. The use of such reforming catalysts for producing aromatic compounds from paraffinic raffinates and naphthas is disclosed. It is known to increase the sensitivity of such sulfur sensitive and selective catalysts. It is believed that the basic reason for the longer development period and slower commercialization of dehydrocyclization technology is the extreme and unexpected increase in sensitivity of these reforming catalysts to sulfur. Equipment operating and processing cost benefits will result from the new methods for sulfur management as provided by the catalyst system according to the present invention.

Desulfurization of naphtha feedstocks in reforming processes using sulfur adsorbents is widely disclosed. U.S. Patent No.
4,225,417 and U.S. Pat. No. 4,329,220 teach a reforming process for removing sulfur from a reforming feedstock using a manganese-containing composition. Preferably, this feedstock is hydrotreated to reduce the sulfur content to 0.1 ppm. U.S. Pat.No. 4,534,943 and U.S. Pat.
No. 75,415 each teaches an apparatus and method for removing residual sulfur from a reforming feedstock using a parallel absorber for continuous operation, in which apparatus and method ideally Sulfur content is reduced to less than 0.1ppm. U.S. Pat. No. 4,456,527 discloses a method for reforming a hydrocarbon feedstock having a sulfur content of at least about 50 ppb using a catalyst containing a large pore zeolite and a Group VIII metal. Various methods for removing sulfur have been disclosed as methods for reducing the sulfur content of hydrocarbon raw materials to 500 ppb or less. U.S. Pat. No. 4,741,819 discloses contacting a feedstock with a reforming catalyst that is less susceptible to sulfur, a sulfur adsorbent, and a highly selective reforming catalyst. U.S. Pat.No. 5,059,30
No. 4 specification describes a physical mixture of a normal alumina catalyst supporting platinum and a sulfur adsorbent containing a group IA or IIA for the purpose of desulfurizing a naphtha raw material for a reformer later. Shows. Platinum / L-zeolite catalysts having increased resistance to sulfur by incorporating rhenium are also disclosed in US Pat. No. 4,954,245. However, none of the above cited materials suggests a catalyst system containing a physical mixture of a sulfur sensitive reforming catalyst and a sulfur adsorbent.

[0005]

The present invention is effective in the dehydrocyclization of paraffins in the presence of small amounts of sulfur.
It is to provide a catalyst system for a catalytic reforming process having a high degree of catalyst stability. Another inevitable objective with it is to avoid sulfur deactivation of reforming catalysts which have a very low resistance to sulfur.

[0006]

SUMMARY OF THE INVENTION The present invention provides a catalytic reforming process system that utilizes a catalyst system comprised of a physical mixture of a sulfur-sensitive conversion catalyst and a sulfur adsorbent to provide a sulfur-sensitive catalyst. It is based on the finding that it is surprisingly effective in trapping sulfur to avoid the inactivation of. A broad embodiment of the present invention is a resistance to sulfur made up of a physical mixture of a sulfur-sensitive reforming catalyst containing a platinum group metal and a sulfur adsorbent containing a metal oxide that is selective to the sulfur adsorbent. It is a catalyst system with. One embodiment of this catalyst system is a physical mixture of a platinum containing reforming catalyst and a manganese oxide sulfur adsorbent. A preferred embodiment of such a reforming catalyst system comprises a potassium form of L-zeolite. Yet another embodiment is a catalytic reforming process that uses a catalyst system that includes a physical mixture of sulfur-sensitive reforming catalysts, at least in the first conversion zone. To reiterate, one broad embodiment of the present invention involves a catalyst system comprised of a sulfur-sensitive conversion or reforming catalyst containing a platinum group metal and a physical mixture of a sulfur adsorbent containing manganese oxide. are doing. This catalyst system captures sulfur by contacting it with a sulfur-sensitive reforming catalyst, which can be surprisingly effective as compared to the prior art in which a conversion catalyst and a sulfur adsorbent are used sequentially. Do you get it. The interaction of the catalyst with the adsorbent also leads to good results in the efficient utilization of the catalyst and in ensuring a favorable yield in the dehydrocyclization operation with sulfur-sensitive catalysts.

First particles of the conversion catalyst and second particles of the sulfur adsorbent
Particles are prepared by the following method. Preferably, the first particles are essentially free of sulfur adsorbent and the second particles are
Particles are essentially free of conversion catalyst. The first and second particles are then mechanically mixed to make a catalyst according to the present invention. These particles can be thoroughly mixed using well known techniques such as mulling in order to intimately mix the physical mixture. The weight ratio of the conversion catalyst to the sulfur adsorbent basically depends on the sulfur content of the raw material and is in the range of about 1:10 to 10: 1. Preferably, 100cc samples of batches mixed at the same time are:
No more than 10% of each component of the mixture associated with the batch will be different. Although the size and shape of the first and second particles are similar, these particles are preferably of size and / or
Alternatively, different densities are convenient for purposes of regeneration or reactivation after use in hydrocarbon processing.

The conversion or reforming catalyst is composed of a composite of metallic hydrogenation-dehydrogenation components supported on a refractory substrate. This catalyst is effective in converting a small amount of sulfur in the hydrocarbon feedstock into the H ₂ S for the reforming process, and this H ₂ S can be easily absorbed, thus deactivating the sulfur-sensitive catalyst. Can be suppressed. This conversion catalyst can withstand even when the sulfur in the raw material rises to about 10 ppm, and the activity is considerably restored. The conversion catalyst also preferably contains oxygen sites for dehydrogenation of the naphthenes in the feed and for isomerization, decomposition and dehydrocyclization.

The refractory substrate of the conversion catalyst must be a porous and homogeneous material of uniform composition without the adsorptive distribution gradient inherent in such compositions. (1) Alumina, silica, titania, magnesia, zirconia, chromia,
Refractory inorganic oxides such as thoria, boria or mixtures thereof, (2) synthetic or naturally derived clays or silicates that can be treated with acid, (3) hydrogen form,
Alternatively, FAU, M in a form exchanged with a metal cation
EL, MFI, MOR, MTW (IUPAC Committee on Zeolite Nomenclature), etc., natural or synthetic crystalline zeolitic aluminosilicates, (4) MgAl ₂ O ₄ , F
Refractory substrates comprising one or more of spinels such as eAl ₂ O ₄ , ZnAl ₂ O ₄ , CaAl ₂ O ₄ , and (5) combinations of one or more substances from these groups are within the scope of the invention. It is within. The preferred refractory substrate for the conversion catalyst is alumina, especially gamma or eta-alumina. Best results were obtained with "Ziegler Alumina" as described in U.S. Pat. No. 2,892,858, which is currently available from Condea Chemie GmbH under the tradename "Pural". Ziegler alumina is a very pure pseudoboehmite that has been shown to become highly porous gamma alumina when calcined at high temperatures. This refractory inorganic oxide has an apparent specific gravity of 0.6-
1-g / cc, surface area 150-280 with a pore volume of 0.3-0.8cc / g
m ² / g (especially 185~235m ² / g) is preferably fairly pure Ziegler alumina having a surface area of. The alumina powder can be molded into any shape or shape known in the art, such as spheres, extrudates, rods, pills, pellets, tablets, or granules. Spherical particles are made by reacting alumina powder with a suitable colloidal acid and water to make the alumina powder an alumina sol, and the resulting mixture of sol and gelling agent is placed in an oil bath. 62
It can be formed by forming spherical particles of alumina gel as described in 0,314, followed by known curing, drying, and firing steps. The preferred extrudate shape is, most preferably, alumina powder mixed with water and a suitable deflocculant such as nitric acid, acetic acid, aluminum nitrate, and a loss on ignition of 45-65% by weight at 500 ° C ( It is made by forming into an extrudable dough with LOI). The resulting dough is extruded through a mold of suitable shape and size to form extruded particles, dried and calcined by known techniques. Alternatively, the extruded particles can be rolled on a rotating disc to make the extrudate.

The essential nature of this sulfur-sensitive conversion catalyst
The component is one or more platinum group metals, especially
China component is preferred. This platinum component is oxide, sulfide
, Halides, or acid halides, etc.
A compound bound to one or more components of a complex, or
The elemental metal can be present inside the catalyst.
Catalytic composite with almost all of the platinum reduced
Best results are obtained when present in the object. this
Platinum content is generally calculated on an elemental basis and
0.01 to 2% by weight of the catalyst composite of, preferably 0.05 to 1
Make up the amount%. Such metal regulators include the periodic table
[Cotton and Wilkinson,Advanced Organic Chemistr
y, John Wiley & Sons (5th edition: 1988)] IVA (14)
Group metals, other Group VIII (8-10) metals, rhenium, iron
Indium, gallium, zinc, uranium, dyspros
Um, and mixtures thereof. Touch of such metal
A medium effective amount is incorporated into the catalyst by any known technique.
May be included. In some cases, the conversion catalyst is a halo.
It may also contain a gen component. This halogen component
Fluorine, chlorine, bromine, or iodine, or their
Any of the mixtures may be used. The preferred halogen component is chlorine
Is. This halogen component usually binds to the inorganic oxide substrate.
It exists in a combined state. This halogen component is preferred
It is well dispersed throughout the catalyst and is the most elemental based.
It constitutes 0.2 to 15% by weight of the final catalyst. Good conversion catalyst
The preferred component is a non-acidic large pore molecular sieve. Appropriate minutes
A child sieve typically has an opening of 7 angstroms or more.
, Or "pore size" with uniform pores, zeolite
AFI, FAU by IUPAC Committee on Naming
Or has a structure characterized as an LTL structure type
are doing. LTL structure is preferred and is not affected by sulfur
The pancreatic catalyst is preferably L-zeolite, alkali gold
A modified catalyst composed of a metal component and a platinum group metal component
It is a medium. Essentially, the acidity of zeolite is
It reduces the selectivity of the final catalyst for aromatic compounds.
This is because the L-zeolite is non-acidic.
To be "non-acidic", a zeolite is its cation
All exchange sites are occupied by non-hydrogen species.
You. Preferably, it occupies its exchangeable cation site
Cations are composed of one or more alkali metals
However, the presence of other cationic species is also acceptable.
A particularly preferred non-acidic L-zeolite is L in the potassium form.
-A zeolite. For use in the catalyst of the present invention
In order to provide a good form, the L-zeolite
It is necessary to complex the with a binder. This technology
Suitable for use with any refractory inorganic oxide binder
Teaching that Silica, alumina, or mug
One or more of the Nessia is a binder material of the present invention
Is preferred as Amorphous silica is particularly preferred, as an aqueous solution
Synthetic why deposited as very fine spherical particles from
Excellent results are obtained when using silica gel powder
Can be The silica binder is preferably acidic, not more than 0.3%.
Contains lower sulphides, and 120-160m²/ g
It has a BET surface area. L-zeolite and binding
The desired catalyst in any known technique by complexing the agents
It can be formed into a shape. For example, add peptizer
Previously, potassium form of L-zeolite and amorphous siliceous
The mosquitoes may be mixed to form a uniform powder.
Can be extruded by adding an aqueous solution containing sodium hydroxide
It forms into a dough. This dough is preferably baked directly
To form an extrudate with the strength to withstand
Therefore, it has a water content of about 30 to 50% by weight. as a result
The dough that can be produced is pressed from a mold that has the appropriate shape and size.
Extrude to form extrudate particles and dry the particles
Then, it is fired by a known technique. Also, the conversion of physical mixtures
It can also be formed by the method described above for the catalyst.
When the alkali metal component contains L-zeolite
Is an essential component of the sulfur-sensitive reforming catalyst.
Lithium, sodium, potassium, rubidium, cesium
System, and one or more of these mixtures
Although possible, potassium is preferred. Arca
The remetal is preferably the non-acidic L-zeolite capsule.
It occupies all of the thion-exchangeable sites. US Patent
Surface deposition as described in 4,619,906
Alkali metal may be present.

Reforming catalysts that are sensitive to sulfur are usually 10
It is dried at a temperature of 0 ℃ -320 ℃ for 0.5-24 hours, then
In air, 0.5 to 24 hours, 300 ℃ ~ 500 ℃ (preferably 350
℃) under the temperature of. Preferably, the oxidized catalyst is subjected to a reduction step in a substantially water-free state at a temperature of about 300 ° C to 550 ° C (preferably 350 ° C) for about 0.5 to 10 hours or more. To be The duration of this reduction step is to avoid catalyst deactivation,
It should be as long as necessary to reduce the platinum, and may be done in-situ at the start of the plant if a dry atmosphere is maintained. For more detailed methods of preparation and activation of sulfur sensitive catalyst embodiments, see, for example, U.S. Pat.No. 4,619,906,
It is disclosed in US Pat. No. 4,822,762. As also discussed below, in this embodiment, the catalyst may include an alkali metal component and the preferred binder is non-acidic amorphous silica. The conversion catalyst formed in the first particles making up the physical mixture according to the invention is usually 100 ° C.
It is dried at a temperature of ~ 320 ° C for 0.5 to 24 hours, and then oxidized in the atmosphere at a temperature of 300 ° C to 550 ° C for 0.5 to 10 hours. Preferably, the oxidized catalyst is subjected to a reduction process under conditions substantially free of water at a temperature of 300 ° C to 550 ° C for 0.5 to 10 hours.

The sensitivity of this conversion catalyst to sulfur is S
It is measured on the basis of sulfur sensitivity called SI. This SSI is a measure of the effect of sulfur in the hydrocarbon feedstock on the performance of the catalyst for catalytic reforming processes, and in particular on catalyst activity. This SSI is measured as the relative deactivation rate with and without sulfur present in the feedstock in the treatment of hydrocarbon feedstocks to carry out a given conversion under given conditions. This deactivation rate is expressed as the rate of increase in operating temperature per unit time (ie, equivalent to a unit of catalyst life) in order to maintain its conversion, and the deactivation rate is usually the equipment. Is measured as the "end of its operation", i.e., the rapid progress of deactivation and the reaching of operating temperatures to excess levels as known in the prior art. The conversion is the octane number of the product,
It is judged on the basis of a certain product yield or the disappearance of raw materials. In the method of the present invention, 0.4 ppm (400 ppb)
The deactivation rate given the sulfur content in the typical feedstock is compared to the deactivation rate in the sulfur-free feedstock. SSI = D _S / D _O D _S = Inactivation rate when the sulfur content in the raw material is 0.4 ppm D _O = Inactivation rate in a raw material that does not contain sulfur In this case, "does not contain sulfur" means The sulfur content in the raw material means 50 ppb, and more generally 20 ppb or less. As one ratio, SSI does not take into account large variations in operating conditions. The essential operating condition that defines the SSI in the method of the present invention is that the pressure is 456 kPa.
(4.5 bar), liquid hourly space velocity (LHSV) is 2 hours
~ ¹ , a hydrogen to hydrocarbon molar ratio of 3, and conditions including conversion of hexane and heavier hydrocarbons in the raffinate from the aromatic compound extract as defined in the Examples. . Other conditions will be described in Examples. The operating temperature is varied to achieve a defined conversion, and the rate of deactivation is measured as the rate of temperature increase to maintain conversion as described above. The SSI of a catalyst sensitive to sulfur is 1.2 or more, preferably about 2.0. Catalysts having an SSI of about 3 or higher are particularly advantageously protected from sulfur deactivation according to the invention. The important thing is
Not only is the sulfur adsorbent according to the present invention effective in removing small amounts of sulfur compounds from hydrocarbon streams under conversion catalyst operating conditions, but in order to maintain the activity of the catalyst, the adsorbent is not The point is that they must be compatible. This sulfur adsorbent contains a metal oxide, the atomic weight preferably contains a metal oxide selected from the oxide of the metal of 19 to 30 or less, in particular, potassium, calcium, vanadium, manganese, nickel. , Copper and zinc are known to be effective in removing sulfur under various circumstances. The adsorbent preferably contains a manganese component. Manganese oxide has been found to be superior to prior art zinc oxide in protecting reforming catalysts, possibly related to the potential for zinc contamination of related reforming catalysts. ing. The manganese oxides include MnO, Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ and M
It includes nO ₃ and Mn ₂ O ₇ . The preferred manganese oxide is MnO (manganese monoxide). In order to obtain the second particles of the physical mixture according to the invention, such manganese oxide is suitable such as clay, graphite, or an inorganic oxide containing one or more of alumina, silica, magnesia, chromia or boria. It may be combined with a binder. Preferably, the manganese component is unbound and is present essentially in the form of manganese oxide. Even more preferably, the manganese component is essentially effective in MnO which is particularly effective in removing sulfur and which has sufficient molecular strength without the use of a binder to make the second particles according to the invention. Is configured. In another embodiment of the invention, the physical mixture of conversion catalyst and sulfur adsorbent is contained within the same catalyst particle. In this embodiment, the catalyst and adsorbent may be ground together or separately to form particles of suitable size, preferably 100 microns or less, and the particles are on a suitable substrate. Is carried by. Preferably, this substrate is selected from the inorganic oxides mentioned above.

The physical mixture of conversion catalyst and sulfur adsorbent is placed in a fixed bed reactor or in a moving bed reactor,
From there, it may be continuously drawn or added. In such a system, (1) a semi-regenerator containing a fixed bed raises the temperature and finally shuts down the unit for regeneration and reactivation of the catalyst to maintain operating conditions. ) When the catalyst is deactivated, the individual fixed bed reactors are sequentially isolated by the manifold folding method, the catalyst in the isolated reactor is regenerated and reactivated, and the other reactors are in the operating state. (3) Continuously regenerating the catalyst withdrawn from the moving bed and reloading the reactivated catalyst to maintain a high level of catalyst activity during a regeneration cycle of several days. To maintain the strictness of the reaction at a high level, or (4) a catalyst regeneration system known to those skilled in the art, such as a hybrid system in which the semi-regeneration and continuous regeneration systems are provided in the same device. Combined with. The catalyst system can be used in hydrocarbon conversion processes, preferably in reforming processes that also use highly sulfur sensitive catalysts. This catalyst system may be placed in one reactor or used in a plurality of reactors having a system known in the art for adjusting the introduction temperature to each reactor. . Raw materials flow into each reactor,
It may be entered in either a descending flow mode or a centrifugal flow mode.
Since the preferred reforming process operates at relatively low temperatures, the centrifugal flow mode is preferred for small temperature drop widths in centrifugal flow reactors.

The operating conditions used in the process of the present invention include pressures in the range of 101.3 to 6078 kPa (1 to 60 atm), with pressures of 101.3 to 2026 kPa (1 to 20 atm) preferred.
And, a temperature of 10 atm or less is particularly preferable. Preferably free hydrogen is fed to the process in an amount corresponding to a ratio of hydrogen in the range of 0.1 to 10 moles per mole of hydrocarbon feed. Here, "free hydrogen" means an H ₂ molecule that is not bound to hydrocarbons or other compounds. Preferably, this reaction is carried out in the absence of added halogen. The amount of physical mixture of catalyst and adsorbent is 0.5-4.
This corresponds to a liquid hourly space velocity of 0 hr ~ ¹ . Operating temperatures generally range from 260 ° C to 560 ° C. This temperature removes the sulfur compounds in the feed from H ₂ to scavenge the sulfur produced by the subsequent contact with the sulfur sensitive catalyst from the process.
Set to convert to S. The naphthenes are generally dehydrogenated on the first reforming catalyst and the latent heat of reaction lowers the temperature of the entire catalyst bed, so the type of hydrocarbon in the feed also influences the temperature setting. At each stage of operation, the temperature is slowly raised in order to compensate for the deactivation of the catalyst which naturally occurs.

The hydrocarbon feedstock is composed of paraffins and naphthenes and may contain aromatic compounds and small amounts of olefins, preferably with a boiling point in the gasoline boiling range. Raw materials that can be used are straight run naphtha, natural gasoline, synthetic naphtha, thermal gasoline, catalytically cracked gasoline, partially reformed naphtha, or raffinate from aromatic compound extracts. The distillation range may be an entire distillation range of naphtha having an initial boiling point of usually 40 ° C to 80 ° C and a final boiling point of 160 ° C to 210 ° C, or a slightly narrow range having a slightly lower final boiling point. Light paraffinic feedstocks such as naphthas from Middle East crude oil with a final boiling point in the range of 100 ° C to 160 ° C are preferred due to the process characteristics of dehydrocyclization of paraffins to aromatic compounds. Low-value C ₆ -C _{8 which} can be converted into mainly valuable B-T-X aromatic compounds
Raffinates from paraffins and aromatics extracts are particularly preferred sources.

Hydrocarbon feedstocks for the present process usually contain small amounts of sulfur compounds in elemental amounts up to 10 ppm. Preferably, the hydrocarbon feedstock is a hydrotreated, hydrorefined, or hydrodesulfurized, pollutant such as sulfurized, nitrided, and oxygenated compound, respectively H ₂ S, NH ₃ and H ₂
It can be made from contaminated feedstock in the usual pretreatment step of conversion to O and then separated from hydrocarbons by fractional distillation. This pretreatment step is preferably carried out using a known catalyst containing an inorganic oxide substrate and a metal selected from groups VIB (6) and VIII (9-10) of the Periodic Table. Instead of or in addition to conventional pretreatment, the pretreatment step may include the step of contacting with an adsorbent capable of removing sulfur-based or other contaminants.
Such adsorbents include zinc oxide, iron sponge, high surface area sodium, high surface area alumina, activated carbon and molecular sieves, and excellent results are obtained when an adsorbent in which nickel is supported on alumina is used. Preferably, the pretreatment step provides a reforming catalyst system with low sulfur level hydrocarbon feedstocks disclosed in the prior art as desirable reformate feedstocks, for example in the range of 1 ppm to 0.1 ppm (100 ppb). Modern pretreatment equipment uses sulfur levels in the range of 0.5 to 0.15 ppm. The hydrocarbon products obtained from the treatment of hydrocarbon feedstocks with the catalyst system according to the invention are essentially free of sulfur. Here "does not contain sulfur"
This means that the sulfur content is 20ppb or less, preferably 14p
It means less than pb. In another aspect, "free of sulfur" means that there is no detectable sulfur. American National Standard Test ASTM D 4045-87 repeatability 20 ppb at sulfur level 0.02 ppm (20 ppb)
Therefore, "no sulfur" in this test would be defined as having a sulfur content of 20 ppb.
However, it is believed that differences can be detected in laboratories conducting tests on a series of similar samples, for example at low sulfur levels on the order of 10 μg / ml or 14 ppb. The catalyst system comprises a first conversion zone containing a sulfur-sensitive conversion catalyst and a sulfur adsorbent, and one or more subsequent conversion zones containing only a sulfur-sensitive catalyst. It can be used in configured systems. The first and one or more conversion zones may be in separate reactors or in the same reactor. A plurality of continuous reactions in which two or more reactors include both a first conversion zone containing the catalyst system and a second conversion zone containing only sulfur-sensitive conversion catalysts. It is within the scope of the invention to use it in a reactor system comprising a vessel. It is advantageous to use a plurality of reactors, each containing both the above physical mixture and the sulfur-sensitive catalyst. In this case, the device contaminated with sulfur either releases sulfur into the feed to the reactor, or the sulfur is blown onto the feed to the reactor. For example, about 0.1 ppm of sulfur with respect to the raw material can be attracted to the surface of a passivation device such as a heater tube. The second and subsequent conversion zones are the same as in the first conversion zone described above, with 101.3
Under pressure of ~ 6078kPa (1-60 atmospheres), preferably 101.3kP
Operate under a pressure of a to 2026 kPa (1 to 20 atm). Good results have been obtained at operating pressures below 1013 kPa (10 atm). The molar ratio of free hydrogen to hydrocarbon is between 0.1 and 1 hydrogen per mole of hydrocarbon from the first conversion zone.
It is about 0 mol. Preferably, this reaction is carried out in the absence of added halogen. The space velocity relative to the volume of the sulfur-sensitive reforming catalyst is 0.2-10 hr- ¹ . The operating temperature ranges from 400 ° C. to 560 ° C. and may be controlled independently of the temperature in the first conversion zone, as mentioned above. The reactants are preferably contacted in descending order with the physical mixture and the sulfur-sensitive catalyst, and steam is added between the conversion zones to control the temperature at which the reactants are introduced to the sulfur-sensitive catalyst. It is within the scope of the invention to spray a liquid, liquid, or mixed phase flow. Using techniques and equipment known in the prior art, the aromatics-containing effluent from the second conversion zone is typically passed through a cooling zone to a separation zone. In this separation zone, which is usually maintained at a temperature of about 0 ° C to 65 ° C, a gas containing a large amount of hydrogen is separated from the liquid phase. The resulting hydrogen-rich stream is circulated to the first conversion zone via suitable compression means. The liquid phase from this separation zone is usually withdrawn and treated in a fractionation system to control the concentration of light hydrocarbons and produce a modifier product containing aromatics. To be done. The following examples are given to illustrate the invention in comparison with the prior art.

[0017]

EXAMPLES Comparative Example 1 The reforming catalyst according to the prior art was investigated for its sulfur sensitivity index. Using the extruded platinum-rhenium supported on alumina chloride as catalyst A, the platinum content was 0.25% by weight, and in the case of rhenium, 0.40% by weight. The SSI of this catalyst was obtained from two comparative pilot plants, one with naphtha containing little sulfur and the other with sulfur spiked with thiophene to bring the concentration of sulfur in the feedstock to 0.4 ppm by weight. Tested by treating hydrotreated naphtha. This naphtha raw material had the following properties. Sp. gr. 0.746 ASTM D-86, ° C: IBP 85 50% 134 EP 193 Naphtha was loaded into the reactor in a down-flow operation. The operating conditions were as follows. Pressure, kPa 1520 hydrogen / hydrocarbon mole 2 liquid hourly space velocity, hr ~ ¹ 2.5 target octane number was 98.0 Research Clear. This test was performed up to an operating end temperature of about 535 ° C. The Sulfur Sensitivity Index was calculated based on the relative inactivation rates with and without 0.4 ppm sulfur in the feed. Within the accuracy of this test, the rate of deactivation is similar when reacted for 1 day at a temperature of 3 ° C, with or without the presence of sulfur in the feed.
SI was 1.0. Therefore, catalyst A was similar to the control catalyst based on the prior art in terms of sensitivity to sulfur.

Comparative Example 2 The sulfur sensitivity index of the second non-zeolitic reforming catalyst was determined. The reforming catalyst in which spherical platinum-rhenium was supported on alumina chloride used for this determination was used as catalyst B.
The platinum content was 0.22% by weight, and the rhenium content was 0.44% by weight. The SSI of this catalyst was thiophene in order to make the naphtha substantially free of sulfur (runs B-1 and B-1 ') and the concentration of sulfur in the feed was about 0.4 ppm by weight. Sulfur spiked (Run B-
2 and B-2 ') and two comparative pilot-plant runs. The naphtha raw materials used in each test were different and had the following properties. B-1, B-2 B-1 ', B-2' Sp. gr. 0.746 0.744 ASTM D-86, ° C: IBP 85 79 50% 134 130 EP 193 204 Naphtha was charged to the reactor in downflow and the operating conditions were as follows. B-1, B-2 B-1 ', B-2' pressure, kPa 1520 1823 hydrogen / hydrocarbon, mol 2 2 liquid hourly space velocity, hr ~ ¹ 2.5 2.5 octane number was 98.0 research clear. The test is
The operation was performed up to an end point temperature of about 535 ° C. The Sulfur Sensitivity Index was calculated based on the relative rate of inertness with and without 0.4 ppm sulfur in the feed, and the results were as follows: B-1 1.6 ° C / day B-2 2.5 ° C / day SSI = B-2 / B-1 = 1.6 B-1 '0.85 ° C / day B-2' 1.1 ° C / day SSI = B-2 '/ B- 1 '= 1.3

Comparative Example 3 The sulfur susceptibility index of highly reformed reforming catalysts was determined. The silica-bonded potassium form L-zeolite reforming catalyst used for this determination was designated as catalyst C, and the platinum content was 0.82% by weight. SSI of this catalyst
One is that naphtha is substantially free of sulfur (Run
C-1) and a second one (Run C) in which naphtha was spiked with sulfur so that the concentration of sulfur in the raw material was about 0.4 ppm by weight.
Tested by treating hydrotreated naphtha in two comparative pilot plant runs with -2). This naphtha had the following additional properties. Sp. gr. 0.6896 ASTM D-86, ° C: IBP 70 50% 86 EP 138 Naphtha was loaded into the reactor in a down-flow operation. The operating conditions were as follows. Pressure, kPa 456 hydrogen / hydrocarbon, mol 3 liquid hourly space velocity, hr ~ ¹² Tests were conducted up to an operating end temperature of about 480 ° C. The Sulfur Sensitivity Index was calculated based on the relative rate of inertness with and without 0.4 ppm sulfur in the feed, and the results were as follows: C-1 0.3 ° C / day C-2 4.0 ° C / day SSI = C-2 / C-1 = 13

[0020]

The advantages of the catalyst system according to the invention in comparison with the prior art are illustrated in the comparison of an example in which naphtha containing 0.5 ppm of sulfur as thiophene is treated at 1000 cubic tons per day. The overall liquid hourly space velocity is 5 for both the inventive example and the comparative example based on the prior art.
The reactor is loaded with equal amounts of conversion catalyst and sulfur adsorbent such that In the case of the present invention, the catalyst and the adsorbent are physically mixed, and in the prior art, the conversion catalyst is loaded onto the sulfur adsorbent. The relative amounts of catalyst and adsorbent are as follows. Conversion catalyst 4.8 tons Sulfur adsorbent 9.6 tons This conversion catalyst is a sulfur-sensitive reforming catalyst as described above, and the presence of sulfur causes a rapid decrease in dehydrocyclization activity. Maintain its capacity until about 0.1% by weight full capacity. The conversion catalyst comprises platinum supported on potassium-form L-zeolite bound to silica. As shown in Comparative Example 3, its sulfur sensitivity index was about 13. This sulfur adsorbent was essentially pure porous manganese oxide with a sulfur capacity of around 5% by weight. The number of days until full sulfur loading demonstrates the advantages of the present invention. Invention 970 days Prior art 9.6 days

[0021]

INDUSTRIAL APPLICABILITY The present invention is a catalyst having a very high industrial effect as a hydrocarbon reforming catalyst having a high degree of stability even when a small amount of sulfur is present. Further, in the case of reforming hydrocarbons using this catalyst, even if a small amount of sulfur is contained in the raw material, it is possible to perform reforming in a high yield without lowering the catalytic activity. is there.

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Claims (7)

(57) [Claims] 1. A physical mixture of a sulfur-sensitive reforming catalyst and a sulfur adsorbent, the reforming catalyst comprising a non-acidic large pore molecular sieve, at least one platinum group metal component and a refractory inorganic oxide. A reforming catalyst system comprising a substrate, wherein the sulfur adsorbent further contains manganese oxide. 2. A first particle composed of (i) a conversion catalyst and essentially free of a sulfur adsorbent, and (ii) a first particle composed of a sulfur adsorbent and essentially free of a conversion catalyst. The catalyst system of claim 1 which is composed of a physical mixture with two particles. 3. The non-acidic large pore molecular sieve is non-acidic L-
A catalyst system according to claim 1 or 2 which is composed of zeolite and the platinum group metal component is composed of a platinum component. 4. The sulfur-sensitive reforming catalyst consists essentially of a non-acidic L-zeolite, an alkali metal component, a platinum group metal component, and an inorganic oxide binder. 3 catalyst system. 5. A catalyst system according to claim 1, which is constituted by a physical mixture of the conversion catalyst and a sulfur adsorbent on the same catalyst particles. 6. A process for reforming a hydrocarbon feedstock comprising the step of contacting the feedstock with a catalyst system as defined in any one of claims 1 to 5 under reforming conditions. 7. The process of claim 6 wherein the naphtha feedstock contains 10 ppm by weight or less of sulfur.