DE3038231A1 - CATALYTIC REFORMING PROCESS - Google Patents

Description

Description The present invention relates to a catalytic Reforming process to improve the octane quality of naphtha in a reforming unit, which consists of a large number of reactors connected in series.

The catalytic reforming or hydroforming process is an in Industrial process well established in the petroleum industry, that of improvement serves the octane quality of naphtha or distilled spirits. In the reforming process a multifunctional catalyst is used which comprises one or more metal hydrogenation-dehydrogenation components (Hydrogen transfer components) contains, which are essentially atomic on the Surface of a carrier made of porous inorganic oxide, primarily aluminum oxide, are dispersed. So far, noble metal catalysts, especially platinum catalysts, applied. The reforming process is driven by the overall action of the molecular Changes or hydrocarbon reactions that occur during dehydrogenation are defined of cyclohexanes and dehydroisomerization of alkylcyclpentanes for the production of aromatics occur, also in the dehydration of paraffins for production of olefins, in the dehydrocyclization of paraffins and olefins for production of aromatics, in the isomerization of n-paraffins, the isomerization of alkylcycloparaffins for the production of cyclohexanes, the isomerization of substituted aromatics and the hydrocracking of Paraffins, which are a gas and inevitably Coke is formed, the latter being deposited on the catalyst.

It is known to use platinum in the manufacture of reforming catalysts to be widely used industrially, and catalysts based on platinum on alumina have been used commercially in refineries for the past few decades. In the last decade, platinum has had additional metal components as activators added to the activity and / or selectivity of the platinum base catalyst to improve, e.g. with iridium, rhenium, tin and the like. Some of these catalysts have a higher activity and / or selectivity compared to other catalysts. For example, compared to platinum catalysts, platinum-rhenium catalysts have excellent selectivity, which selectivity is defined as that Ability of the catalyst to produce high yields of C5 liquid products in addition to competing low production of normally gaseous hydrocarbons, i.e. methane and other gaseous hydrocarbons, as well as coke.

In a conventional process, the heart of the reforming aggregate is from a number of reactors. Everyone Reforming reactor is used in the Usually provided with fixed catalyst beds, over which the feed upwards or flows downwards, and each reactor is further equipped with a preheater or equipped with a reheater because the reactions that take place are endothermic.

A naphtha feed is combined with hydrogen or recycled Gas passed through a preheater furnace and reactor and then in turn passed through the subsequent reheaters and reactors in sequence.

The product from the last reactor is turned into a liquid fraction and exhaust gas separated. The exhaust gas is rich in hydrogen and usually contains small amounts of ~ normally gaseous hydrocarbons, one of which is hydrogen for the C5 liquid product is separated and returned to the process to the Decrease coke production.

The catalyst activity gradually falls due to the increase in Coke formation. The coke formation is believed to be due to the deposit of coke precursors such as anthracene, corones, ovals and other aromatic molecules with condensed Rings based on the catalyst, which polymerize to form coke. While during operation, the process temperature is increased in stages to avoid the loss of activity, caused by the coke deposit. Determine if necessary but economical Reasons the need to reactivate the Catalyst. Thus, in all processes of this type, the catalyst must necessarily be used periodically regenerated by burning off the coke under controlled conditions will.

Two main types of reforming are typically used in aggregates carried out with several reactors, with each of the two types of processes periodic reactivation of the catalyst is required with a Regeneration, i.e. the burning of the coke on the catalyst, begins. The reactivation of the catalyst is then completed in a series of stages in which the agglomerated metal hydrogenation-dehydrogenation components again atomically dispersed will.

The first type of process is a semi-regeneration process proceeded in such a way that the temperature gradually increased in the entire unit is increased to maintain the catalyst activity impaired by coke deposition, until finally the entire unit is shut down in order to regenerate the catalytic converter and reactivate. In the second or cyclic type of process, the reactors are individually isolated, or they can be motorized with the help of various devices Swing out driven valves and the like. The catalyst is regenerated to to remove the deposits of biscuits, and then reactivated during the other reactors in the series are in operation. A "swivel reactor" temporarily replaces the reactor, which is out of the series for the purpose of regeneration and reactor vation of the catalyst removed until it is brought back into line.

Various improvements have been made to these processes to increase the efficiency of the reforming catalysts to increase the capital investment to reduce or improve the yield of C5 + liquids and the octane quality increase in naphthas and distilled spirits.

Platinum-rhenium catalysts are among the handful of more successful ones of well-known industrial catalysts in terms of their selectivity an excellent one Position on: they also have good activity.

Both the amount and the type of catalysts have been changed, with which the various reforming reactors in a number were charged in order to to modify or change the nature of the products or to reduce the yield of C5 liquid to improve.

There were also different ones in the various reactors in the series Catalysts with various catalytic metal components are used. In the U.S. Patent 3,684,692 discloses the use of platinum-rhenium catalysts in the various Reactors described, with a neutral alumina support in the introduction reactors was used while the final reactors with. an acidic oxide carrier for the Dehydrocyclization. The acidic carrier contains 90% alumina and 10% hydrogen exchanged synthetic faujasite; both are catalysts chlorinated.

In U.S. Patent 3,660,271 to Keith et al., A catalytic reforming process is disclosed for naphthene and paraffinic hydrocarbons for the production of products described with improved octane quality. The first reactor or reactors of the rows contain a platinum group metal coated on a substrate containing, weakly acidic catalyst which is essentially free of rhenium, i.e. it contains less than about 0.05% by weight, preferably less than 0.01% by weight or no detectable amount of rhenium. This catalyst is used for dehydrogenation of naphthenes. The final reactor or reactors, preferably the last Reactors of the series contain a metal applied to a carrier material the platinum group and rhenium containing catalyst of high acidity, which is used for Dehydrocyclization of the paraffins is used. In one example, a system with four Described reactors in which a chlorinated platinum metal catalyst (0.6 z Pt / 0.7 % Cl / Al203) is used in the first three reactors in the series, and one is chlorinated Platinum rhenium Catalyst (0.6% Pt / 0.6% Re / 10.7% Cl / 90% Al203 / 10 % H-faujasite), which is used in the last reactor in the series.

A very similar process is used in U.S. Patent 3,705,095 to M.H. Dalson et al described as in the aforementioned US-PS, but it differs in that that the catalysts added to the various reactors are based on aluminum oxide are applied. According to U.S. Patent 3,658,691 and U.S. Patent 3,705,094 (both to Keith et al.) the rhenium-containing catalyst in the induction reactors of the series applied.

Thus, in the first patent specification, a method is described in which a platinum rhenium chloride / acid oxide catalyst in the output reactor for the dehydrogenation is applied and in which a platinum chloride / alumina catalyst is used in the final reactor for the dehydrocyclization. According to US-PS 3 705 094 will be platinum rhenium chloride / alumina catalyst in the first three Reactors and a platinum chloride / alumina catalyst in the last reactor of the Row used. A platinum-rhenium catalyst is also used on the basis of GB-PS 1 470 887 used in the first stages, and a platinum-iridium catalyst is used in the final reactor used. Other interesting patents dealing with this area, U.S. Patents 4,167,473, 3,516,924 and 4,174,270.

While in this way through variations and modifications tries has been carrying out the procedure in relation to some selected objectives the process, there are nonetheless still desirable ones Improvements to the known reforming process, making the present invention the underlying task is to create a reforming process that enables higher conversions of the feed material in liquid C5 + naphthas than this with the conventional reforming process can be achieved.

According to the invention, this object is achieved by a catalytic reforming process dissolved in a reforming unit to improve the octane quality of naphtha, that from a large number of reactors connected in series including an introductory reactor, a final reactor and optionally one or more between the introductory and the final reactor lying reactors consists of each of which contains a platinum-rhenium catalyst, with the naphtha in sequence flows from one reactor in the series to the other, with the catalyst flowing under it Reforming conditions in the presence of hydrogen. The inventive Process is characterized in that in the catalyst of the final reactor maintain a greater concentration of rhenium relative to the concentration of platinum is than in the catalysts of the other reactors, the atomic ratio of Rhenium: platinum in the final reactor is maintained at at least about 1.5: 1, while in the other reactors a lower to at most the same concentration of rhenium is complied with in relation to the concentration of platinum.

The reforming process according to the invention therefore comprises a series of reforming zones or reactors, each of which contains a catalyst bed, the catalyst in the introductory reforming zone made of platinum and a relative low concentration of rhenium on a support material and the catalyst in the last reforming zone or in the last reactor of the series made of platinum and consists of a relatively high concentration of rhenium, the amount of rhenium to the amount of platinum in the last reforming zone or the last reactor in an atomic ratio of at least about 1.5: 1 and higher, preferably at least about 2: 1 and higher, and most preferably from about 2: 1 to about 3: 1. Under reforming conditions, the catalyst beds are in contact with a hydrocarbon or feed naphtha and hydrogen to produce a hydrocarbon naphtha product improved octane quality; the product obtained is then withdrawn.

In preferred embodiments of the method according to the invention are the introduction zones or introduction reactors of the series with a platinum-rhenium catalyst with the atomic ratio of rhenium: platinum in the range of about 0.1: 1 to about 1: 1, preferably from about 0.3: 1 to about 1: 1, and the latter Refantifng-ione or 7. the last reactor of the series with a platinum-rhenium catalyst is equipped, the atomic ratio of rhenium: platinum in the range of about 1.5: 1 to 3: 1, preferably from about 2: 1 to about 3: 1.

It is known that the amount of coke formed in one approach progressing from the introductory reactor to the following reactors resp. increases from the first to the last reactor in the series, in consequence of the different Types of reactions that prevail in the various reactors. So plays in the first reactor in series the location of the metal or the hydrogenation-dehydrogenation component of the catalyst plays a predominant role and the predominant reaction the dehydration of naphthenes to aromatics. This reaction takes place at relatively lower levels Temperature instead of, and the coke formation is relatively low. In the middle Reactors (usually a second and a third reactor), on the other hand, play a role the acidic places play a bigger role, and the isomerization reactions prevail here before, although additional naphtha are formed and these as in the first Reactor to be dehydrated to aromatics. In the two middle reactors there is one higher temperature than maintained in the first reactor, and the temperature in the third reactor is higher than that in the second reactor in the series. The carbon formation takes place in these reactors to a greater extent than in the first reactor in this series, and coke formation is higher in the third reactor than in the second reactor in this series. The main reaction in the last reactor in the series is a dehydrocyclization of Paraffins and olefins, and this reactor has the highest reaction temperature applied. This is also where the strongest coke formation takes place, and the reaction is often particularly difficult to control. It is also common knowledge that the rising Amounts of coke in the various reactors in the series cause considerable deactivation of the catalysts. While the relationship between coke formation and the Rhenium production to increase the catalyst selectivity because of the extreme interdependence of these reactions is not known with certainty, it is assumed that the presence of rhenium lessened the adverse effects of increasing coke levels, though it does not appear that coke formation is reduced in the absolute sense. Nonetheless, according to the present invention, the concentration of rhenium in those Increased reactors in which the coke formation is greatest, but especially in the last reactor in the series. Therefore, in a special embodiment of the invention, the catalysts within the series of reactors with regard to their Rhenium concentration gradually graduated, the rhenium concentration from first to last reactor in the series increases in such a way that the rhenium content the platinum-rhenium catalysts is varied considerably to get the normal effects to counteract coking.

In one embodiment of the invention, an optimal use is made the rhenium-enriched platinum catalysts achieved in that one in the first Reactor of the series provides a catalyst with a rhenium concentration that an atomic ratio of rhenium to platinum in the range from about 0.1: 1 to about 0.5: 1, preferably from about 0.3: 1 to about 0.5: 1. The catalyst in the middle Reforming zones, represented by the middle reactors between the first and the last reactor in the series, has a rhenium concentration that corresponds to an atomic ratio from rhenium: platinum in the range from about 0.5: 1 to about 1: 1, preferably from about 0.5: 1 to about 0.8: 1Z corresponds. The last reactor in the series is with a catalyst equipped, which contains a rhenium concentration which has an atomic ratio of Rhenium: platinum corresponds to about 1.5: 1 to about 3: 1, preferably from about 2: 1 to about 3: 1. The last reactor in the series contains fewer than 3 regardless of the job in the series or more than 3 reactors, always a catalyst with an atomic ratio of rhenium: platinum of at least 1.5: 1, preferably from about 2: 1 to about 3: 1.

The catalyst used according to the invention necessarily exists composed of particles which, in addition to a carrier material, have one or more Hydrogenation-dehydrogenation components and a halogen component contain, wherein the catalyst is preferably sulfided.

The carrier material consists of a porous, heat-resistant inorganic Oxide, preferably aluminum oxide.

The carrier material can consist of one or more components, for example from aluminum oxide, bentonite, clay, diatomaceous earth, zeolite silica, Activated carbon, magnesia, zirconia, torre earth, and the like, although most preferred If the support material is aluminum oxide, a suitable amount can also be used, if desired another heat-resistant carrier material, such as silica, Zirconia, magnesia, titania, etc., usually in an amount of about 1 to 20%, based on the weight of the carrier material. According to the invention possesses a carrier material preferred in practice has a surface area of more than 50 m² / g, preferably from 100 to about 300 m² / g, a bulk density from about 0.3 to about 1.0 g / ml, preferably from about 0.4 to about 0.8 g / ml, an average pore volume from about 0.2 to about 1.1 ml / g, preferably from about 0.3 to 0.8 ml / g and one average pore diameter of about 3 to 30 nin.

The metal hydrogenation-dehydrogenation component can be mixed with the porous, inorganic oxide carrier material mixed or otherwise closely connected are shared using various well-known processes such as ion exchange Precipitation with aluminum oxide in the sol or gel form and the like Catalyst composition by adding the appropriate reagents such as a Platinum salt and ammonium hydroxide or carbonate and an aluminum salt such as aluminum chloride or aluminum sulfate can be formed to produce aluminum hydroxide. That the aluminum hydroxide containing platinum salts can then be heated, dried, shaped into pellets or extruded and then under nitrogen or a others are not calcined to a completely internal atmosphere. The metal hydrogenation components can also be added to the catalyst by impregnation, typically with the help of the "beginning moisture" technique, where a minimum of solution is required is so that the entire solution is immediately after the addition or after some evaporation The platinum and the rhenium and, if appropriate, are absorbed additional metals used as activators with the help of the impregnation method to an extruded one previously processed into pills, tablets, pearls and the like or sieved particulate support deposited.

According to this method of impregnation, it becomes porous, heat-resistant inorganic oxides in the dry or solvated state either alone or in a mixture with a metal or a metal-containing solution or metal-containing Solutions brought into contact or otherwise incorporated with them, thereby making them either by the "incipient damp" technique or by some other technique be impregnated, in which one or more diluted or concentrated solutions absorbed in the carrier material and then filtered or evaporated, to bring about a complete take-up of the metallic components.

In general, platinum is applied to the substrate in an amount in Range from about 0.01 to 3% by weight, preferably from about 0.05 to 1% by weight, based based on the weight of the catalyst (dry basis). Rhenium is also used usually on the support material in a concentration in the range of about 0.1 to about 3% by weight, preferably from about 0.5 to about 1% by weight, based on weight of the catalyst (on a dry basis). Of course, it will be the absolute Concentration of both metals preselected to the desired atomic ratio of rhenium to obtain platinum for a specific reactor of the reactor aggregate.

In the final reactor there is a larger amount of rhenium relative on the amount of platinum, whereas in contrast to this in all other reactors Rhenium in a smaller or no more than equivalent amount relative to the amount of platinum, based on the atomic weight of these metals.

When applying the metals to the carrier material can essentially Any compound can be used, but soluble compounds are preferred can easily be subjected to thermal decomposition and reduction, for example inorganic salts such as halides, nitrates, inorganic complex compounds or organic salts such as the complex salts of acetylacetone, amine salt and the like, if Platinum is to be deposited on the substrate, preferably platinum chloride, Platinum nitrate, chloroplatinic acid, ammonium chloroplatinate, potassium chloroplatinate, platinum polyamine, Platinum acetylacetonate and the like are used. If another activating metal besides If platinum and rhenium should be used, it will be in a concentration in the range from about 0.01 to 3% by weight, preferably from about 0.05 to about 1% by weight, based on based on the weight of the catalyst.

About the efficiency of the catalytic converter in the reforming process To increase it, it is also necessary to add a halogen component to the catalysts to be added, fluorine and chlorine being preferred as halogen components. The catalyst contains the halogen in an amount of about 0.1 to 3% by weight, preferably of about 1 to 1.5% by weight, based on the weight of the catalyst. When chlorine as a halogen component used it is added to the catalyst in an amount of about 0.2 to 2% by weight, preferably from about 1 to 1.5 qew.J based on the weight of the catalyst, added. the Introduction of halogen into the catalyst can be done at any time with any suitable Method to be carried out. The halogen can be added to the catalyst during catalyst manufacture may be added, for example before, after or simultaneously with the incorporation the metal hydrogenation-dehydrogenation component or components. It can through it be introduced that one can have a carrier material in a vapor phase or liquid Phase with a halogen compound such as hydrogen fluoride, hydrogen chloride, ammonium chloride and the like.

The catalyst is by heating to a temperature above about 27 C, preferably between about 650 and 1,500 C, in the presence of nitrogen or Oxygen or both in a stream of air or under vacuum. The catalyst is at a temperature between about 2600 and 6500C, preferably about 2600 to 5380C, either in the presence of oxygen in an air stream or in the presence an inert gas such as nitrogen is calcined. A very preferred component of the Catalysts is sulfur, whereby the sulfur content of the catalyst is usually in the range up to about 0.2 wt. t, preferably in the range from about 0.05 to about 0.15 % By weight, based on the weight of the catalyst <dry basis). The sulfur can be added to the catalyst using conventional methods, for example through this, that you have a sulfur-containing gas stream, for example Hydrogen sulfide in. Hydrogen, passes over a catalyst bed, the Catalyst is sulfided until the absorption threshold is reached. This method is used at temperatures in the range from about 177 to about 5660C and at pressures im Range from about 1 to 40 bar carried out as long as necessary to reach the absorption threshold or to achieve the desired sulfur content.

The starting material can be fresh naphtha, cracked naphtha, a naphtha from the coal liquefaction process, a Fischer-Tropsch naphtha and the like. like. be. These feedstocks can be sulfur or nitrogen or both contained in fairly high concentrations. Typical feed materials included Hydrocarbons with about 5 to 12 carbon atoms, particularly preferably with about 6 to 9 carbon atoms.

Hydrocarbons of this type are in naphthas or petroleum fractions with a boiling point in the range from about 270 to 2320C, preferably from about 520 up to about 19O0Cj.

Typical fractions usually consist of about 15 to 80 percent by volume Paraffins, which can be both normal and branched, with about 5 to 12 C atoms, from about 10 to 80 percent by volume naphthenes with about 6 to 12 C atoms and from 5 to 20 percent by volume of the desired aromatics with 6 to 12 carbon atoms.

The reforming attempts are made by adjusting the hydrogen and Feed rates, temperature and pressure on the process conditions in motion. The experiment is carried out under optimal reforming conditions by means of adjustment of the main procedural variables continued in the following areas: Main process - Typical process - preferred variable conditions driving conditions -Pressure, kg / cm² 3.5-52.7 7.0-21.1 reactor temp., C 482-649 510-566 speed of the recycle gas, SCF / B 1000-10000 1500-3000 feed rate W / Hr / W 0.5-10 2.5-5 The invention is further developed below on the basis of comparative data explained. Unless otherwise indicated, all parts are parts by weight.

A number of platinum-rhenium catalysts were used for demonstration purposes high rhenium from portions of particulate alumina of a conventional one Type used in the manufacture of industrial reforming catalysts is produced. These alumina fractions are those from one particle size extrudates of 0.158 cm passed, were calcined log at 5380C for 3 hours and then Equilibrated with steam within 16 hours.

In each case, the carrier was impregnated with the metals carried out by adding H2PtCl6, HReO4 and SCl in aqueous solution, whereby Carbon dioxide was added as an impregnation aid. After 2 hours of equilibrium the mixture was filtered, dried and stored in a vacuum oven at 150.degree. C. for 16 hours.

Before reforming naphtha, the catalyst was below 5100C a mixture of 6% oxygen and 94% nitrogen and then heated for 1 hour impregnated with C12 / 02 (500 ppm Cl2, 6% 02r 5000 ppm H2). Then the Catalyst for 3 hours under a gas mixture of 6% oxygen and 94% nitrogen kept at 5100C and then cooled to 4540C, with 1.5% hydrogen in Reduced nitrogen and then presulphided with H2S in this reducing gas, to achieve the desired sulfur content in the catalyst.

The platinum-rhenium catalysts used in other than the final reactor were of the usual type and were obtained from the catalyst manufacturer.

The test results of the loads used in the tests are compiled in Table I below.

TABLE I Freshly Made Paraffinic Naphtes Light Naphtha tha from Persian from Arabia Gulf API-spec. Weight 59.7 58.9 sulfur, wppm as 0.5 nitrogen, wppm <0.1 0.1 bromine No. cg / g 0.12 0.1 ASTM distillation: initial boiling point. OC 82.2 74.5 5% 100.5 95.0 1 0 102.8 102.1 20 111.1 107.3 30 116.7 115.0 40 123.9 12278 50 130.0 131.5 60 136.8 139.5 70 145.4 148.4 80 153.0 157.0 90 162.4 167.5 95 169.0 174.6 final boiling point 194.2 181.0 ° C In a first cyclic simulated Reforming experiment (experiment No. 1) was a catalyst with a high rhenium content, containing 0.3% Pt / 0.67% Re / 1.1% Cl2 / 0.15% S in the various reactors a unit consisting of 4 reactors is used, with all 4 reactors were in operation. The catalyst was prepared as described above.

In a second experiment (experiment No. 2) all reactors were the series with catalysts with a low rhenium content, the 0.3% Pt / 0.3 t Re / 1.1 8 Cl2 / 0.15% S, charged. The experiments were carried out in the manner that one can use light paraffinic Arabian naphtha *) at 510 ° C E.I.T., a pressure of 12.3 kg / cm², a recycle gas velocity of 3,000 SCF / B, the conditions necessary to make a product with a research octane number of 102.0 RON are required, passed through the reactors in series. The results are summarized in Table II.

* d. H. equivalent isothermal temperature, that is the between The temperature at the inlet and outlet of the reactor.

TABLE II Catalyst Yield in Activity Units Cg LV% Trial No. 1 (high content of rhenium) 96.0 69.3 Experiment No. 2 (low content of rhenium) 102.0 72.0 These values show that the use of catalysts with high rhenium content in the various reactors in the series the yield of C5 liquid and the Decreased octane number considerably. It is believed that this is due to the "cracking." out ") the aromatic precursor is returned to the introduction reactor. This The conclusion is also drawn from the 20% increase in light petroleum gases, mainly the C3-C4 hydrocarbons made using catalysts with high rhenium content, supported.

Example 1 A third experiment (experiment lir. 3) was carried out under similar Conditions carried out with the same feed except that the three lead reactors with your catalyst with low rbenium content sent and only the final reactor was filled with the catalyst with a high rhenium content (28 wt. of total catalyst charge). The results are in the table III and are compiled with the results of the previous experiment compared with the low rhenium containing catalyst.

TABLE III Catalyst Yield of Activity Units C5 + LV% Experiment No. 2 (low rhenium content) 102.0 72.0 Experiment No. 3 (lower 102.0-72.5 content of rhenium in the introduction reactor / noher content of rhenium in Final reactor) The values obtained show that by grading the catalysts with low and high rhenium content, as described, a respectable yield än C5 liquid is obtained. The handsome yield of C5 liquid is furthermore by increasing the purity of the recirculated hydrogen (approximately 1%) for the staged reactor system.

Example 2 In a fourth experiment, the fourth reactor in the series as a final reactor with a dry calcined catalyst with 0.29% Po / 0.72 % Re / 1.1% Cl2 / 0.14% S and the first three reactors with a catalyst loaded with a low rhenium content. The attempt became more difficult with one Paraffinic naphtha to be reformed from the Persian Gulf at 510 ° C E.I.T., 12.3 kg / cm², 3000 SCF / B and a space velocity sufficient to produce a product with a research octane number of 1001.

This trial was compared to a fifth trial, the one below identical conditions with a low rhenium catalyst in all four reactors was carried out.

The results are shown in Table IV.

Table IV Catalyst Yield of Activity C5 LV% units Experiment no. 4 (low rhenium 92.0 75.5 content in the feed reactor / high rhenium content in the final reactor) Experiment No. 5 77.0 74.3 (low rhenium content) The improvements in the catalyst activity and in the yield are clearly visible. The attempt shows besides the improved activity and high yield when using the more difficult Feed also that one with the high rhenium catalyst a far greater coke tolerance in the final reactor than in the conventional experiment achieved, even under very harsh conditions (522 ° C E.I.T.) in the final reactor, as Table V shows.

Table V Mol% H2 in the yield of the yield of recycled H2 (% by weight) C1-C4 (wt.%.) Gas based on based on gas charge charge test no. 4 77.1 2.31 17.86 (low rhenium content in the feed reactor / high rhenium content in the final reactor, experiment no. 5 76.2 2.26 18t82 (low rhenium content) Obvious Further modifications and changes can also be made within the scope of the invention Process can be made in which the excellent features of the invention Process, namely that the octane quality of various hydrocarbon feedstocks, especially including paraffin feed materials, upgraded and improved can be.

Claims (8)

Catalytic reforming process Claims 1. Catalytic Reforming process to improve the octane quality of naphtha in a reforming unit, that from a large number of reactors connected in series including an introductory reactor, a final reactor and optionally one or more between the introductory and the final reactor lying reactors consists of each of which contains a platinum-rhenium catalyst, with the naphtha in sequence flows from one reactor of the series to the other, with the catalyst flowing under it Reforming conditions in the presence of hydrogen in contact, characterized in that that in the catalyst of the final reactor a greater concentration of rhenium in relation on the concentration of platinum is maintained than in the catalysts of the other reactors, with the atomic ratio of rhenium: platinum in the final reactor at at least about 1.5: 1 is maintained, while in the other reactors one lower to at most the same concentration of rhenium in relation to the concentration of platinum is adhered to. 2. The method according to claim 1, characterized in that the atomic ratio of rhenium: platinum in the catalyst of the induction reactor in the range of about 0.1: 1 up to 1: 1. 3. The method according to claim 1, characterized in that the atomic ratio of rhenium: platinum in the induction reactor in a range from about 0.1: 1 to about 0.5: 1 and in the reactors located between the inlet and outlet reactor ranges from about 0.5: 1 to about 1: 1. 4. The method according to any one of claims 1 to 3, characterized in that that the atomic ratio of rhenium: platinum in the catalyst of the final reactor is in the range from about 2: 1 to about 3: 1. 5. The method according to any one of claims 1 to 4, characterized in that that the catalyst of the final reactor contains about 0.01 to about 3% platinum. 6. The method according to any one of claims 1 to 5, characterized in that that the catalyst of the final reactor contains about 0.01 to about 3% rhenium 7th Process according to one of Claims 1 to 6, characterized in that the catalyst of the final reactor contains about 0.1 to about 3% halogen. 8. The method according to any one of claims 1 to 7, characterized in that that the catalyst of the final reactor is sulfided and contains about 0.2% sulfur