BE738336A - - Google Patents

Description

  

   <Desc / Clms Page number 1>
 
 EMI1.1
 



  Hydmcarbon reforming process.

 <Desc / Clms Page number 2>

 
 EMI2.1
 



  The present invention relates to methods of reorganizing the hydroc.arbre $; and more specia.les3nt res o w.Ve processes coinduced at low pressures in order to produce gasoline with high octane number.



  The refo! '#.:; E is well known in the petroleum industry and
 EMI2.2
 designates will treat it; naphtha fractions in the presence of hydrogen
 EMI2.3
 and a catalyst having a d-6.ihydro natio-n resistance to improve the octane number. During a period of 4t:; ilisaieas the activity of the catalyst decreased for several reasons., One of which resided in the deposition of carbon and carbonaceous batiere on this catalyst. the catalyst must be replaced prit3iqueent; or, more adamtageuscnent, the catalyst must be restored periodically by heating it to a high temperature, for example, in the presence of an o> j.Ei gas to restore at the end some of the initial cat3lytic activity.

   Consequently., The processes of roform3, -, e can 8trc classes in .gr0s according to the period of operation left before the replacement of the
 EMI2.4
 spent catalyst with fresh catalyst, or regeneration of spent catalyst, as appropriate. The method of the present invention should
 EMI2.5
 -be distinguished from the procedures, of reionsase which work during periods of walking, before the- r6gntian of-a few hours. or a few Y ge lans ie-que? a:, r.êī \ -9.9itr # '.pr, , 9.e. ±! Tb ti; 3, ge in which the catalyst is 3.s in contact with a naphtha 1. for a period of at least 2000 hours before the replacement or the regeneration.



  : Most CD.i-.alytiqu reformare processes that ag1st.mt for long periods of i: al'cl1e $. Operate at high reaction pressures, by erewie pressures ES.nor: riqu3S above 24 bars approximately, and more specia.le # nt at nno-; 5triques pressures between 28 and 35 bars approximately. He failed up. present at high pressures in order to control the deposition of the co-ke and the deactivation of the catalyst.

   When the reforssge is carried out at low mano-u6trîqLes pressures, for example less than 17 bars in-
 EMI2.6
 virons - to produce good-quality gasoline with an index
 EMI2.7
 octane of at least 980 conventional catalysts used up to
 EMI2.8
 present become clogged quickly, i.e. become inactive,
 EMI2.9
 thus preventing the refopjBage processes from operating for periods of operation greater than 2000 hours with an excess drop in liquid yield in 5+ ', for example drops in liquid yield in Ce'! ' equal to or greater at 2% by volume for a period of 2603 hours.

   However, it is dirty in the lei0l.C 'industry that the processes of!' Efor'ï:; ase c & talytiqu8 at low pressures produce substantial sustentations of the rcn: '1eDant in pre-
 EMI2.10
 sensing a high octane number, Air-si, extensive research has been devoted to the development of low-twisting processes

 <Desc / Clms Page number 3>

 
 EMI3.1
 pressures and catalysts r use in such pro = 6sEx. Cospto given the increased dC1de of ear-ences 4 high oetse index, and in particular, COI1pte..tom: de la. pressure from public authorities to cn- 4cher the use of lead in gasolines in order to improve. the innovation of oatane, the development of reor # 3a processes at low
 EMI3.2
 pressures have grown in importance.
 EMI3.3
 



  The erdr4 catalysts? cn used for the rearag procedures contain plaiIn = supported by porous solid vehicles, for example 1Ial1119'- It is possible to conduct the èCorm3 ± c procedures with low supported platinum catalysts6. pressures for long periods of mreha, eg over 2000 hours, but only with catalyst compounds and / or reinforcing conditions which render the processes economically unattractive.

   Thus, extremely high proportions of platinum, for example greater than 1 percent by weight, can be used on a catalyst so as to allow the reaction process to run at low pressures to produce d-index gasolines. High octane, however the price of platinum makes this means of reforging at low pressures unattractive. Other ways of stopping low pressure rerorreae include lowering the hourly liquid space velocity due to the 4qroe molaira ratio, - ne / .ydrgearburq these means nē
 EMI3.4
 are yen advantageous because of the d1r: reduction of the cha-rce treated in the first case and the high price which the remxe entails in circulation.
 EMI3.5
 hold of hydrogen at low pressures in the second case.

   By
 EMI3.6
 As a result, it is evident that low pressure methods of producing high octane gasoline for long periods of operation have only increased to low pressure. present difficulties which have effectively consumed them from being practical from an industrial point of view. '- # - "" #' ....................... The United States patent dOB3.1l1cs to 'A> x # r' that n S60 165 of June 2, 1966 and n 639.719 of May 19, 1967 describe a new
 EMI3.7
 Catalytic composition useful for reforming processes.



  The catalyst described in the aforementioned patent applications comprises a porous solid carrier or support containing platinum.
 EMI3.8
 and rheinium as an intimate mixture. In addition, the catalyst is described as exhibiting greater selectivity and greater
 EMI3.9
 stability with respect to catalyst included platinum without
 EMI3.10
 rhenium during ¯rei'orl! 1st of a fraction of naphtha free of
 EMI3.11
 sulfur.
 EMI3.12
 



  The Applicant has found that the coosit1on of the catalyst comprising supported platinum and rh0nium p :: tr a solid catalyst vehicle I) or {::} J .: is particularly suitable for a rifOi'Ii :. .F "-, v t3. Low pressures and G # 5 of cogitions r2so.-ucvJxs, c'cct-

 <Desc / Clms Page number 4>

 
 EMI4.1
 ¯ à-dirc a reformza at dos pressures t; inoz6t; iquoz less than about 17 bars, to produce a gasoline having mid octane number ne (0 '03 t-à-c1ir0 without lead compound) of at least gt3 .

   The process of the present invention for the catalytic rerorm, e of a l1.::.pl1ta to obtain a reformed product having w.i. A net octane number of at
 EMI4.2
 minus 98 includes contacting naphtha and hydrogen with
 EMI4.3
 a porous oxidative vehicle containing from 0.01 to 1 weight percent active platinum per 0.01 to 2 weight percent rhenium under az pressure conditions comprising anometric pressure of less than 17 bar approximately, an hourly liquid space velocity of at corners 2, and a molar ratio of hydrogen to hydrocarbon (E2 / HC) less than the value at Qrmin4o by the equation.



  H2 law; -; - &: 1 0.0062x .k .hO where x is the temperature increased to 95 volumetric percent of the naphtha are distilled during a distillation following the ASTI- t1âtl1odo! D-fi & ,. and where I., depends on the net octane number (1.0.) of the reforming product being produced according to equation s
 EMI4.4
 . k = -o, 058 (1 * o.) + 510 ..



  The process is characterized by a time period of at least 2000 hours with a drop in the C5 + liquid yield which is not greater than z. 2 percent in voluna laying 2,000 hours. L9 is particularly suitable for use with the porous nincral oxide vehicle alunino cocsae.



  As a particular embodiment, the preparation of the present invention comprises the catalytic ro1'r.Y'-go of a naphtha. the tenpation at which 95 volume percent of the naphtha is distilled during an ASTH D-86 diatillation being between 171 and 1F3 C., to obtain a reinforcase product with an octane number
 EMI4.5
 net of at least 98, the process being characterized by a torch period of at least 2000 hours with a drop in liquid yield
 EMI4.6
 in C5 + which is not greater than 2 percent by volume for 2000 hours, in nottn-nt in contact naphtha and hydrosene with a catalyst comprising a porous mineral oxide conasa vehulo containing 0.01.

   at 1 percent by weight of active platinum by 0.01 to 2 percent by weight of rhenium under standard conditions comprising a pressure not less than about 17 bars, an hourly liquid space velocity of at least 2, and a ratio molar hydrogen / hydrooarburo less than 5.4, when producing a roforcasQ product having a net octana number of 98 and being increased by about 2/3 of a mole of hydro-
 EMI4.7
 Ùne per unit of octane number when the octane number of the product
 EMI4.8
 de reforr..e is raised from 98 to io4.



  The invention will be better understood by referring to the drawings.
 EMI4.9
 annexes on which

 <Desc / Clms Page number 5>

 
 EMI5.1
 Figure 1; if: an 8laphic which shows, as a function of the temperature at which 95 volume percent of a naphtha is distilled by making an ASTH D-86 distillation (hereinafter often referred to as the boiling point temperature do 95%).

   the molar ratio of hydrogen to hydrocarbon (H2 / HC) required to reform naphtha to gasoline having a specified octane number using a catalyst comprising platinum and rhenium (curve 1) and a carbon
 EMI5.2
 tàlyseür containing platinum without rhenium (curves 2 to #) the curves in this figure are based on the correlations of the net octane number of the product, the molar ratio of hydrogen to hydrocarbon, and the 95% boiling point, of a naphtha for re-
 EMI5.3
 'forùaco has a high pressure of about 17 bars, and an hourly liquid space velocity of 2; curves 1 and 2 concern processes d9 refo.3.3 making it possible to produce gasoline with a net octane number of 98;

   curves 3 and 4 relate to re- processes. forced to produce gasoline with an octane number
 EMI5.4
 net of 100 and 102 * respectively
 EMI5.5
 Figures 2 and 3 are graphs which show by way of comparison the reforKase behavior of a conventional catalyst containing platinum on an alumina support, and a catalyst containing
 EMI5.6
 nant platinum and rhônium on an alumina support.

   L3S operating conditions for the reforming process using the
 EMI5.7
 supported platinum include a pressure w: 1nomstrlqua of about 14 bars and a thydro3èn to hydrocarbon ratio of. :: ... t1o # tl "ic of about 14 bars ot a molar ratio of hydrogen to 1 '> ihydrooarbide of 8 during the 1400 preferred hours of foacioh..ron', then a solar ratio of 3 'hydroL23 the hydrocarbon of 6. The hourly liquid space velocity for the two reforzare processes is.



  1I: 8ri: e and is at least 2. The graph of tipime 2 versus as a function of running time, the average temperature of the catalyst needed to intercept a product with a net dtoctane number of 100. The graph of figure 3 show as a function of the duration of !! ark .. the rencctb in liquid in C5 + ,, expressed in percent by volume, of a gasoline produced having a net octane number of lo0, the behavior The superior performance of the reforming process using the supported platinum-rhenium catalyst compared to that of the reforming process using the rhenius-free platinum catalyst is shown in Figures 2 and 3 *;

   which -, in pnocôdô The catalyst which finds an application in lo proceeds from
 EMI5.8
 ref1) rt1ase at low pressures and û3nS conditions ---- r1toUZ'euae 'of: - The present invention comprises usa porous ri11naral oxide cosso vehicle had 4 carrier-containing from 0.01 to 1 lice * hundred in weight of active platinum per

 <Desc / Clms Page number 6>

 0.01 to 2 percent by weight rhenium. Porous inorganic oxides serving as vehicles or supports and which find application in the present invention include a large number of integers.
 EMI6.1
 in which the catalytically active amounts of platinum and rhenium can be provided.

   The term “porous” inorganic oxide support denotes an inorganic oxide having a specific surface area preferably between 50 and 700 m2 / g, and preferably between 150 and
 EMI6.2
 700 m 2 / g. The support can be constituted by inorganic oxides produced in a natural or synthetic manner, or combinations of inorganic oxides. Typical acidic inorganic oxides as carriers which may be employed are the natural aluminosilicates, particularly when treated with acid to increase activity, and the synthetically produced cracking carriers.
 EMI6.3
 rt, for example, silica-alumina, silica-zirconium oxide, silica-alumina-zireoni oxide, illca-genes1e; silica-alumina-magnesia, and crystalline zeolite alujainosilicates.

   However, generally. The reforming processes are preferably carried out in the presence of catalysts having a low cracking activity, ie catalysts having a limited acidity. Consequently., The ca-
 EMI6.4
 Preferred analyzers are inorganic oxides such as naglesiut1 oxide and alumina.
 EMI6.5
 



  The particularly preferred catalyst carrier or carrier for the purposes of the present invention is aluminum. Any suitable form of alumina can be used as the carrier for reforging catalysts. In addition, alumina can be prepared by various methods suitable for the purposes of the present invention. The
 EMI6.6
 Preparation of the bzz alumina for use in cooling catalysts is well known in the art.



  The platinum and the rhéniua are arranged in mid-lanca intima with each other on the porous mineral oxide serving as a catalyst support.
 EMI6.7
 sister. Platinum and rhenium can be disposed on the porous inorganic oxide serving as a support in Balança Intima by appropriate techniques, CODmS by ion exchange, co-precipitation, preton, etc.



  One of the metals can be associated with the support by a process. stopped the ion exchange, and we can associate the other metal with the vehicle
 EMI6.8
 by another process, coEso the itpregnation. However, metals are usually associated with the porous etineral oxide of the base by impregnation. The catalyst can be prepared either by co-impregnation of the metals on the porous mineral oxide carrier or by EiuccG'3alvo impregnation. In general, the carrier cattery is impregnated with an aqueous solution of a decoroposable compound of the metal at a concentration sufficient to obtain the desired amount of estai in the teraln6 catalyst; the resulting v4> nce is then heated to silminate the water. Chloroplatinic acid constituted G4ner.

 <Desc / Clms Page number 7>

 preferred source of platinum.

   It is also possible to use other possible compounds containing platinum, for example chloropla-
 EMI7.1
 Ammonium tinates and polyaluminum salts. Rhenium compounds suitable for incorporation into the carrier include, inter alia, perrhenic acid and ammonium perrhCxnates.
The present invention contemplates incorporating the metals into the support at any particular stage in the preparation of the catalyst.

   For example, if the metals are to be incorporated on an alumina support, the incorporation can take place while the alumina is under sol or gel force, and it can be followed by precipitation.
 EMI7.2
 alumina. Alternatively, # one can impregnate an alumina support. previously prepared with an aqueous solution of tetallic compounds.ândpendas3t of the process for preparing the supported catalyst of platino-rhenium ,, it is desirable that the platinum and the rhenium are in intimate mixture with each other on the support,
 EMI7.3
 and further that the platinum and rhenium are thoroughly dispersed throughout the porous inorganic oxide serving as a catalyst carrier. lyser.



  Aie-tut-alyzeur propo: 36 For the reforging process at low pressures and under severe conditions, the present invention comprises platinum in an amount between 0.01 and 1 percent by weight, preferably between 0 , About 2 and 1 percent by weight, and more preferably between 0.4 and 1 percent by weight, based on the catalyst.
 EMI7.4
 Seur terrands Platinum conoentrations of less than about 0.01 weight percent are too low for return operations ''. On the other hand, platinum concentrations greater than about 1 percent by weight are generally unsatisfactory.
 EMI7.5
 suitable due to the high price of Botanical platinum.

   Cos3 stated above = zr.t ,, higher concentrations of cloot-to-diro platinum greater than 1 percent by weight, could be used for roforluge at low pressures and under severe conditions # but the reinforcing process is generally considered COKC3 being economically uninteresting due to the high amount of platinum required. The concentration of rhenium in the finished catalyst composition is preferably between 0.01 and 2 percent by weight, and preferably between. 0.1 and 1.5 percent by weight, and more preferably between 0.1 and 1.0 percent by weight.
 EMI7.6
 using higher rhenium concentrations "the price of rhenium limits the amount" incorporated into the catalyst.

   It is better to
 EMI7.7
 that the ratio of rhenium atoms to platinum atoms is between 0.2 and 2, and preferably it is preferable that the atomic ratio of rhenium to platinum not exceed 1. Atomic ratios can be used. higher c'cst-à-diro higher than 1. from xh.é.niuo to platinum, ori spokes do not generally improve.

 <Desc / Clms Page number 8>

 
 EMI8.1
 aunt.

   Following 1 "1 maor, poratlon of platinum and rhenium in the porous oxide Dînerai opposite thus obtained is usually heated to a temperature per sxelg not less than. 2CO" C and preferably between 93 and 2C4 C approximately, Subsequently, the composite can be calcined at an elevated temperature, for example ranging usq.t '6S0oc. if desired, -
 EMI8.2
 - The support containing platinum and rhenium is preferably
 EMI8.3
 rence heated to a high temperature to transform the platinum and rhenium to a metallic state. The heating is preferably carried out in the presence of hydrogen and preferably in the presence of anhydrous hydrosene, in particular it is preferable that this prior reduction be carried out at a temperature of between 3160 and 704 c., And preferably between 316 and 5380.

   In addition .. the catalyst
 EMI8.4
 of the present invention preferably exists during the process of
 EMI8.5
 re1'ornage with platinum and rhenium in the metallic state. Thus, in general, depending on whether the platinum and the rhenium are or are not previously reduced to the metallic state before contacting the naphtha under the conditions of reinforcing at low pressures, the t3tals must be reinforced. at. state n: -etall1. <ue during the roforrase process when sulfur is excluded from the
 EMI8.6
 charge.



  The composite catalyst of the present invention, i.e.
 EMI8.7
 Said platinum and rhenium supported on a porous metal oxide as a vehicle "may be sulphided prior to contact with the naphtha to be reformed. The presulphurization can be carried out in situ or ex situ by passing a sulphide gas through IP-3. Example H: 2S JI through the catalyst bed. Other presulfuration techniques are known in the art. Alternatively, the catalyst can be sulfurized initially by adding a C'11fur6 "compound, for example R 2s. or di # thyldisulfide "in r0forse shingles in the presence of naphtha. The exact strength of the sulfur used in the sulfurization process is not critical.

   Sulfur can be introduced into the reaootionnolle zone anyway cOJ!:! 1ode and at any place CQode.- It to be contained in the liquid charge bydrocai & bonée, the gas rich in hydrogen, the
 EMI8.8
 recycle liquid stream to a recycle gas stream ,, or
 EMI8.9
 any corib1naison. After having carried out the reinforcing process in the presence of sulfur for a short period of operation in cornpara, 1- its duration of its duration: .. osav: .. eé:;: ae:; e: 3e which can be obtained with catalysis: m "> 1 the addition of sulfur is preferably discontinuous.

   The purpose of presulf-mation of the catalyst before contact with naphtha or of :: mlfurD.ticll of the catalyst during initial contact
 EMI8.10
 with naphtha is to reduce the initial excessive activity of hydro-
 EMI8.11
 cracking of the catalyst which results in the production of X'O to 3tF "" - 3Ilâ high in ler3 hydrocarbon gases, for example nethanej, during,

 <Desc / Clms Page number 9>

 the first part of the twisting process.
 EMI9.1
 



  The catalyst can be activated by refomage - 'by 2'add.-. tion of halides - in particular a fluoride or a chloride. The halosenides appear to impart a limited degree of acidity to the catalyst, which is advantageous in most redesign operations.
 EMI9.2
 . Forcing * The halide active catalyst preferably contains 0.1 to 3 weight percent of the total halide content, and more preferably 0.1 to 2 weight percent.

   The halides can be incorporated into the catalyst vehicle at any suitable stage in the manufacture of the catalyst, except before or after the incorporation of the platinum and rhenium. Often a certain amount of a halide is incorporated. in the vehicle during impregnation with Dotaux eg impregnation with acid
 EMI9.3
 chloroplatinJLque results norsaleasnt by the addition of chloride to the vehicle. An additional amount of halide can be incorporated into the support, if desired, in the incorporation of the real.

   In general, the halides are combined with the catalyst vehicle by matting; in contact with the vehicle suitable compounds cures hydrofluoric acid, s2nauza fluoride, hydrochloric acid, or armonlum chloride, either in the gaseous form or in the water soluble form. Preferably, the fluoride or chloride is incorporated into the vehicle from an aqueous solution containing the halide.



  The charge integer to be used in the reforming operation
 EMI9.4
 is a light hydrocarbon oil, for example a fraction of naphtha. Generally. r.aphtha- bout between 21 and 288 c. and preferably between 66 and 232 "C ,, the filler material may be, for example, either a preEier naphtha and, or a taer.iaue: .nt or cataly- t3quc: nt cracked naphtha, or their -élp..ges. From prérC-re4-ice, the 1 "...: lphta. is hydrogenated naphtha, eg, aciracaaqa naphtha. The feed for the purposes of the present invention is preferably at a temperature at which 95 11 vol. Percent has been distilled during distillation ASEI4 D- $ 6 (ASTI-1 Si: ar3axds', Petrolet: rs Products .. Fuels, Solvents.

   ZngoeP Tests, * Lubrlcating Oils, Cuttlng 0ils, Grease, Part 17, 1965) of at least 149 c, not more than 204 c .. and preferably between. 160 and 19> c, and preferably between 171 and 283 C approximately. That is to say that for a fraction of naphtha preferably finding an application
 EMI9.5
 For the purposes of the present invention, 95 volume percent of said naphtha was distilled off during ASTM D-86 distillation at a temperature within the ranges given above.

   It is preferred to characterize the boiling point of the feed as a function of the temperature at which 95 volume percent of the feed has
 EMI9.6
 been distilled during the AS% 1 D-E6 distillation, because this temperature is more reproducible than the actual 1 "inal point of the charge

 <Desc / Clms Page number 10>

 
 EMI10.1
 and further indicated the boiling characteristics of the char, $ a. A fraction of naphtha, often contains small amounts of high boiling point constituents thus the final boiling point of the feed .. as it is neither; on6 by 4S.t distillation, # is very high, and did not indicate the top-, where the naphtha msse is distilled.



  It is preferable that the filler for the purposes of the present invention is 5en3lent except .dehyde, 'o'is to say that the-' filler should preferably contain less than 10 parts per rdllison (ppm ) -about soufra and preferably me; w of 5 ppa, and: again. better less than 1 PPIJ. In the case of a load which has. already a content. high in sulfur, acceptable propc: \ '1ons can be achieved by hydrogenation of the whole of charcoal in a prexatnration zone
 EMI10.2
 where the naphtha is in contact with a hydrogenation catalyst which re-
 EMI10.3
 exists in poisoning by sulfur. A suitable catalyst for this hydrodeacturing process is, for example, a support containing alumium and a small proportion of molybdenum oxide; and cobalt oxide.

   The wvàrodésuîura.bion is carried out habitzel3.arnb at a temperature between j99 and 454 c, at <mne eanoisetric pressure between 3 and 140 bars approximately, and at an hourly liquid space velocity CQbpr1se between i, and 51- 1e sulfur contained in naphtha es1; -generalpe tra! 1i1ô, oge <"su1rur.é which can. Be e¯ :. 't .n, v. Rrx é' e 'g' '' r, ss4, '' * appj - + The low pressure reorientation process of the present invention is characterized by producing gasoline having a net octane rating of at least .98 for at least 2000 hours with a low pressure. ..fàS (. 'du i'I3.S'aCs ^ T3 in liquid in (: 5+ which it tests. not higher percent in vol1. !!: during 2,030 hours.

   A period of 1. "ei'or :: lge for example the period of tssps existing before the response or regeneration is required, less than 2000 hours., Is generally not economically attractive. . For example the costs occasioned by stopping the operation of a reactor in order to regenerate the catalyst either in situ or due to too frequent regeneration, that is to say regenerations after a 4o running time of less than 2000 hours. Regenerations too
 EMI10.4
 frequent are undesirable not only because of the whole and the manpower they require, but
 EMI10.5
 loss of tess. to produce gasolines with an octane number <elàµ0.

   In, .. T ', 3, se xlu readecent in liquid eh 5+ su!,? Érie.ÙI'e at; v: rFxïeli; h 2t0'l, .es estE..ér.e.izt coasidered as- being-little eoorl # 1q. for Vgpnoc6dé de reror-; J, se. If the return to6jén, qzt '$: r'-e' ^ $ ,, 5;:. Say 3.reretcîerrt n üntice, e C. dimimte to. a you greater than. 2.% by volume in 2 COO hours,
 EMI10.6
 the catalyst then clogged: too quickly, which thus necessitates -
 EMI10.7
 too frequent catalytic converter or regeneration

 <Desc / Clms Page number 11>

 
 EMI11.1
 in order to restore catalytic activity. The reforming process of the present invention can operate for a period exceeding 2000 hours if desired.

   Cep311dant for the purposes of
 EMI11.2
 present invention, the reforming process is characterized by a
 EMI11.3
 lowering of the renzidedent in liquid in this not more than 2 percent by volume # ... t3osurë for the preniéztex 2 003 hours of re1'orcage. A1nzl-. for example, a reòrnaze process in which the torch .r1: Ode 'is 4000 hours and the liquid content decreases.



  4000 hours is greater than percent by volume! 33 is still economically advantageous and the process falls within the scope of the present invention if the drop in liquid yield in this case.
 EMI11.4
 first 2,000 hours is not more than. 2 percent by volume.



  In a: particular achievement force of this
 EMI11.5
 In accordance with the invention, it is preferable that the method is characterized by a wash-up period of at least 2600 hours with no greater decrease in liquid yield. 2 percent by volume in 2,600 hours.



  Thus, the longer the reroxnze process can work between
 EMI11.6
 catalyst placements or regenerations with only one
 EMI11.7
 decrease in liquid yield in 0 -! - by 2 percent by volume, the more economical the process in general. The a3irQ ratio of hydrogen to hydrocarbon should generally be at "1" when the 7s è. # :. ons &2; refor, r. E! 1 \; longer periods of r3rehe. ' ASSMS '
 EMI11.8
 The pressure of the zone Z'éact1 "de refor ±? 1.ge ai.DC purposes of the present invention is less than about 17 bars per minute.



  Preferably, the canoe pressure is at least about 5 bs'-rs, but less than about 17 bars, and preferably, it is at least 9 bars, but less than 17 bars. The pressure is è6tGl "'it11n6e Corsica eta ..." 1t the DOyenne pressure of the reactor. Thus, for exer-ole, in a process in which several reactors are in serle the czar-rye
 EMI11.9
 flowing from the outlet of one reactor to the inlet of another reactor
 EMI11.10
 tor. the pressure of the reor.ge process, that is to say the pressure 1n ± greater than 17 bars at r # no:; 'li e "is the It-oyeriIle of the pressures re-
 EMI11.11
 gaining through the various reactors.
 EMI11.12
 



  The charge rate to be used in the present invention, i.e. hourly liquid space velocity, is at corners 2.0.



  , High space velocities.- ,, that is to say at blackas 2, o, allow larger, charso voluces to be processed, which adds l: 'd'conot11o du pnoctis do!' C (; 2: gQ-. Preferably, the speed of citar- 'ce'Ùab an hourly "liquid space speed" between 2 and 6' and preferably between 2 and 4. The hourly liquid space speed is Drained as a function of the volujne of charge per volute of catalyst and traversed V% 1'r, r "-. Ia" E. The temperature of the retorID'3.ge process is set between 316 and 593 C. . and preferably between 371 "

 <Desc / Clms Page number 12>

 
 EMI12.1
 and 566 0.

   The Lepsatuu'e is determined, however, by the other operating conditions3 a'ext-E that at a pressure tme viteocG
 EMI12.2
 space liquid hourly ot a partial hydrogen / hydrocarbon ratio
 EMI12.3
 cu110rsJl the tesgpsrltltre is determined by the desired ootano index of the product to be obtained.



  The refOrw: 1g6 generally results in the production of hydro; -ne, so it is not necessary to add an excess of hydroscno in the upgrading process, Ccpr..dntl it is 1w.b1tuol1en: e: r preferable to introduce a hydrogen exeôa at a certain Xtido of the functionnexat, OOF.m9 for example at dCt ^ rrGQ. The hydroer can be introduced into the c3aar; e before contact with the catalyst or it can be contacted sir.r .. \ lt.au0r nt when the feed is introduced into the urdaotionnclle zone.

   Generally, the hydrogen is recirculated over the catalyst before contact of the feed and the catalyst. The rofortaz of a naphtha fraction is carried out by contacting the naphtha and the hydroze: 10 under rei'ol-ze conditions with the.
 EMI12.4
 desired catalyst. Hydrogen can be mixed with hydrocarbons;
 EMI12.5
 gaseous le0crs # by excnplo le HtiTanB. The hydrogen serves to reduce the coke eruption which tends to poison the catalyst. In addition, the presence of hydrogen can be used to promote certain reinforcing coisse 3'lsoa.:,: Rssai.ion, deGbydrogélt1on or hydrocracking. GeneralCIDntl recovers the hydrosene from the renction11cloJ 'products and is generally purified and recycled in the sono raotiop-n011o.

   The Za3.-re: hydrogen / hydroarbt # c ratio required for the purposes of the present invention is high at the inlet <2u reactor and in 10 cases of several reactors in series at the inlet of the first reactor. The tCI'D) "hydrocarbon" used to determine the Molar ratio of hy;> x "; na the hydrocarbon (1i / 11J) is the hydroearbortoo charge or 11 :: lpht-J..1I and n ' not include the l1ydrocaI'bon8 1gor3 gases from the rich recycle stream on I:., '(i O (L "s2 This is evident from the spuc1a11ateG. - ..
 EMI12.6
 



  For the purposes of the present invention, the molar ratio hydroe; ene / l1yc1roC: ll "> bure must be lower than the determined value.
 EMI12.7
 .by the relation i 0, 00 i? x - ic irC
 EMI12.8
 where x is the temperature eQ Fàlaquene 95 pour-cont in VOUn13 to naphtha are distilled during the distillation ASTH D-85 and; where 1 <is defined as a function of the octane number n3t (1.0.) of the gasoline or of the reform product obtained according to the relation 3 k W -0033 (1.0 ..) 5.10 * - /, 111S1 , r <\ p: Jol't; r.1 (Jlv.1.ro f;: lxlr ... J.l byili: o.1bno,! hydrocD.l "'buro D. (. 7.1i1! coiblo aU):

   1 "! NQ de'l pJcnto invcnton vario affects the boiling temperature for the purposes of * the invention varies according to the temperature of 6 u: -

 <Desc / Clms Page number 13>

 
 EMI13.1
 lition do ¯95% da 1 charge in the course of rC1'orr..age and according to the net octane number of the product of reformed in the course of production according to the equations above.

   At molar ratios of hyc3.ro :: c to hycocarbUl'o lower than the value ùàtérrùin60 by the above equations and under the other conditions of reinforcaco mont1orm6cIJ for the present invention that is to say a lower pressure at approximately 17 bars per roll, and a specific speed:

  1.tiaJ.e liquidated hourly at rno1n3 2, reinforcase processes will produce a gasoline with a net octane number of at least 98 using platinum catalyst containing no more than 1.0 percent by weight of plabine, rhenium-free spokes, are not characterized by a u.2roha period of at least .2000 hours with a drop in the liquid yield in this + which is not greater than 2 percent by volume in 2000 hourly, the relation of the ratio of water to hydrorbide to 95 boiling point of the feedstock and the octano number of the gasoline produced will be. better understood by referring to figure i.



  The graph in figure 1 shows the relationship between Io molar ratio 1.so; eno / Y: y necessary to produce a gasoline with a desired octano number and the temperature at which 95
 EMI13.2
 volume percent of naphtha is distilled during one dist111D; to11 ASTH D-86. The curves (curves 1 to 4) are obtained from the correlations of the hydrojéno / liydi? Ocarbide ratio, the net octane number of the charge for Io refornago at an hourly liquid space velocity of 2 and a manon pressure ± about 17 bars.

   The rerorBe process is characterized by a tarry period of 2000 hours with a decrease in the liquid yield of Cl + of? percent in volume 2000 hours, My curve 1 is based on a process of reforming parL * 6% amb to produce a gasoline with a net ocmne index of 98 using a catalyst containing CO aluRdns; p: rCre4 "1t platinum and ruminum wherein the platinum content is about 0.6 percent by weight and the content on rhenium is about 0.6 percent by weight based on the final composition. of the catalyst.

   Curves a, 5 and 4 are ringed on reforging processes using all1rrn () catalysts containing about 1..0 percent by weight of platinum without rhe1'l3um allowing the production of rhe1'l3um. gasolines z octane number re3t ue 93e 100 and 10.2 .. respsctivecentt
 EMI13.3
 Oourbo 2 in figure 1 is defined by the equation
 EMI13.4
 lodged. 000'x-- le where 1 ± is dcal at 1. * 38 and x is the diÓbUllit1on- point in T of 55% of the chai-1 go * This relation between the molar ratio of llliydroc - :); bne 4 l The hssirocarbon and the 95% W charro tenperature concerned U: 1 ppoccC'5 of reformed uses a catalyst containing 1.0 percent by weight of platinum and not containing gold in which the preOD! O :;

  1
 EMI13.5
 

 <Desc / Clms Page number 14>

 
 EMI14.1
 tnancstrric is do z. 7 bars approximately and the hourly liquid space velocity is 2. L3 determined hydrogen / hydrocarbon colar ratio
 EMI14.2
 according to the equation above for a particular charge Integer
 EMI14.3
 is the lowest hydroeene / hydrocarbon molar ratio that can be used. and which further enables a low pressure roformaae process under severe conditions using a rhenium free platinum catalyst to produce gasoline with a net ootane number of 98 for a narche time of at least 2000. hours with a drop in the yield in, liquid in Which is not greater than
 EMI14.4
 more than 2 percent by volume in 2000 hours.

   Has mo-
 EMI14.5
 hydrogen / hydrocarbon waxes, the process using a carbon dioxide
 EMI14.6
 The rhenium-free platinum analyzer does not operate for the desired time with little drop in yield; wanted. In addition, an aloi-
 EMI14.7
 decrease in pressure Up to around 17 bars at the r.:nomètro requires an increase in the hydrogen / hydrocarbon molar ratio in order to obtain the O3m transformation into gasoline with an octane number. from 98.

   In a euialogue way, increasing the space velocity to more than 2 requires an increase in the hy3rorjilydro-carbide molar ratio, in order to obtain the r3x? tl? ansfol? Irc3 tion in a gasoline with an octane number of 93. the decrease in the concentration of platinum in the
 EMI14.8
 catalyst Up to -! not less than 1 percent by weight ne-
 EMI14.9
 An increase in the hydrone / hydrocarbon molar ratio ... also ceased in order to obtain the desired level of rarsforr, tio1.

   A> wi, it is obvious that the express ion e3.dossus for the .ola: 1ra hydrogen / hydrocarbon ratio in order to produce a gasoline with octane number of 9v (k - 1.38) gives the molairo hydrogen / Lowest tolerable hydrocarbon for the reroring process using a 1-Latin catalyst comprising not more than 1 percent by weight platinum and melting under roforiraz conditions comprising a molecular pressure of less than about 17 bars and an hourly liquid space velocity of 'at. rnoin .:

  1 2, and with the running time and decreasing. from ..ren #. wanted-4 '"'" '........ "11" l1rtét1on of the hydrogen / hydrocarbon light ratio is
 EMI14.10
 necessary in order to increase the octane number of the gasoline fraction
 EMI14.11
 produced during the boost while keeping the hourly liquid space velocity and pressure constant - eg an hourly liquid space velocity of 2 and a gauge pressure of about 17 bars.

   Airai, referring to Figure 1, curves 3 and 4 show the relationship of the hyalipgene / hyùrooariide colaire ratio and the boiling teredrature of in order to obtain a gasoline with a natural octane number of 100 and a gasoline. having a net octan number of 102 $ res.pcctivemant, when the reforrilling is carried out with a platinum catalyst The conditions of roforrnaze other than the hydro molar ratio, Jènc / J1ydrocarburo feel the LCmes for curves 2, 3 and

 <Desc / Clms Page number 15>

   A logarithmic expression analogous to that used to define. curve 2 can be used to define curves 3 and 4, but @tvc a value other than !:

  , k varies according to the octane number read produced according to the expression
 EMI15.1
 c .. -0.0J8 (ro) + 510., "", the value of k decreases from a value of approximately 1.38 for an index ['octane of 98 to a value of approximately 1.20 for an index of octane e 102.



   Referring to curve 1 in the figure, we notice ,, to
 EMI15.2
 example, qua reroruage a naphtha. having a tez: ïrArature to water 95 percent by volume distilled during a distillation
 EMI15.3
 STiI D-86 at 171 C, under conditions of i% erorn * ge comprising a reduction of about 17 bars at a pressure gauge and an hourly liquid space velocity of 2, to produce gasoline with an octane number of 98, requires a hydrogen / hydrocarbon light ratio of at least 3.4, when a catalyst comprising 0.6 weight percent platinum and 0.6 weight percent rhenium is used,

   so that the process is characterized by an operating time of at least 2000 hours with a drop in the yield of C5 + liquid not greater than 2 per volume in 2000 hours (point "a" of curve 1) . Else
 EMI15.4
 : 1rt, in reforming an analogous feed under analogous forming conditions to produce a product having an octano number and 98 using a catalyst comprising 1 weight percent platinum without rhenium,

   a hydrogen / hydrocarbon molar ratio of at least
 EMI15.5
 zincs 5p4 is necessary so that the reforo2ro process is characterized by a running time of at least 2000 hours with no line of the liquid yield in Ce -} - which is not greater than 2% 1 volume in 2,080 hours (point "b" on the curve 2).



   In a preferred embodiment of the present invention, a naphtha feed having a temperature at which 95% by volume has been distilled during an ASTM D-86 distillation.
 EMI15.6
 at a temperature of between 171 and 288oC, can be achieved in order to obtain a reforming product having a net octane number of @ins 98 during an operating period of at least 2000 hours with the drop in liquid yield in the process. C5 + which is not more than percent by volume in 2000 hours.

   The naphtha feed and hydro-encumbrance are contacted with a supported platinum and enium catalyst containing 0.01 to 1.0 weight percent platinum and
 EMI15.7
 , 01 to 2 percent by weight of rhenium in a reinforcing zone under reinforcing conditions comprising a pressure less than 17 Lra on about the nanorotor, an hourly liquid space velocity of at least 2, and a role ratio ..x3ra1 h5.di, o; ône / hyd;,> narfiizi'c of 504, frsgu 'a do reforn :: 3Ee product is produced having an ocmne t ll1ôiICè of 98, a molar ratio' rax1r: Al hydrozene / h " t'oca.rbure auzrwntant

 <Desc / Clms Page number 16>

 
 EMI16.1
 ¯ 28 mole of hydrogen per unit of octane number at 1n $ ensure that the octane number of the reforging product being produced is increased from 9S to 104.

   Under the chosen reformaz conditions, in particular with a molar ratio mnxim * 1 hyr; nejhyâ ..- ocabure of 5¯4 # - and preferably of bzz, and above the ga of. Ohargo boiling temperature / a reforming process using a platinum catalyst not costing more than 1 per weight of platinum and not including rhenium is not characterized by a working time of 'at least 2,000 hours with a drop in re
 EMI16.2
 Aenent in C5 + liquid that is not more than 2 percent by volume for 2000 hours when making a reforma product having an octane number of at least 98.

   Thus, with reference to the poin
 EMI16.3
 ube 1 curve 2 of FIG. 1, it can be seen that the re-drilling of a load at a low rlu2t.on point,. This is a feed which exhibits a 95% boiling temperature of 171 ° C. with a platinum catalyst having 1.1 t? weight percent platinum under the most favorable reforrrA conditions-sa requires a hydrogen / hydrocarbon molar ratio of at least 5.4 in order to maintain the re-drilling process for 2031 hours with reduced liquid yield in C 5+ which is not more than 2 percent by volume.

   With higher boiling point feeds, hydrogen / hydrocarbon ratios are required
 EMI16.4
 Thus, with the charge p? 'ése31x1t a boiling tenrature of $ 5% of 188 c, a hydrochloride: ej.yéracarbxr2 molar ratio of 8.3 is necessary (see point "c", curve 2 of figure 1).

   In order to increase the octane number of the reforming product obtained while restoring at a pressure less than about 17 bars on a manometer and at an hourly liquid space velocity of at least 2, the molai ratio @
 EMI16.5
 hydro => m.C '/ 1..lydrocalbU!' e must be aocru to care about 2/3 of rrale of hydrogen per unit of octane number to masure that the octam number of the product reforming rate is increased from 98 to 104, A lower increase.
 EMI16.6
 



  #ntatlon of the molar ratio hy ± + ôgone / hydroca # bàre, less than S / 3 approximately, with the measure that the dtoctanē index of the product increases results in - too rapid fouling of the catalyst, which eKp3che the pro - reforming allowed to operate for up to 2,000 hours with a drop in yield not exceeding 2 percent by volume.
 EMI16.7
 this' following is given by way of illustration, but not limited to the invention.
 EMI16.8
 



  A low pressure rerorm4¯ process using a catalyst containing about o6 weight percent platinum and 0.6 weight percent rhenium, supported on alumina. is cowzaré with a low pressure re'e..e process using a conventional catalyst cos: taking O1 percent by weight of platinum supported by alumina.

 <Desc / Clms Page number 17>

 . The supported platinum-rhenium catalyst is prepared by
 EMI17.1
 impregnating a prelablerent platinum-alumina support impregnated with an aqueous solution containing perrhenic acid. The catalyst is air dried at 66 ° C for about an hour, then heated in air at 371 C for about an hour.

   Then the catalyst containing impregnated alumina is subjected by means of
 EMI17.2
 "platinum and rhenium in an atmosphere of hydrogen at 371 C for about an hour to reduce the levels,
The feed used for the reforming processes is hydrocracked naphtha containing 0.1 ppm nitrogen and 0.1 ppm sulfur. The feed has a boiling range of between about 99 and 216 ° C. The temperature at which 95 volume percent of the feed is distilled during distillation ASTM D-86
 EMI17.3
 is 189 "C.

   The re! 'Or # g.e processes are carried out at pressures of about 14 bar gauge, and hourly liquid space velocities of at least 2e. The hourly liquid space velocities for both processes are the same.



   The hydrogen / hydrocarbon molar ratio of the re-
 EMI17.4
 ror = go using Io platinum catalyst is 6.0.L> polar hydrogen / hydrocarbon ratio for the reforming process using platinum-rhenium catalyst is 8 for the first 1,400
 EMI17.5
 hours of operation; after 1,400 hours; the solar hydrogen / hydrocarbon ratio is set up to a value of 6. Lo Eclaire hydrog; azejïd.z'ocariur :: ratio for both processes is lower than the value determined by. the equation log #### Sp O ,, 0062x - k. -. ---- - '"<-x>" ex ->. log He YYL3i ¯¯¯ ¯.¯¯-- where k is about 1.30 because gasoline must be produced with a net octane number of 100.



   The reforming product having a net octane number of 100
 EMI17.6
 is produced during the operation of the two punching processes.



   The above comparison between the catalyst containing platinum and rhenium and the catalyst containing only platinum is shown in Figures 2 and 3 of the accompanying drawings. The change in average catalyst temperature required to maintain the product at a desired 100 octane number is shown in Figure
 EMI17.7
 FIG. 2 and the yield of C 5+ gasoline in the product of ref'orr: J3.1.? e having an â'oetane number of 103 is r¯-reinxst.t3 in FIG. 3; It can be seen from Fig. 2 that the supported platinum-rhenium catalyst exhibited high activity during the reinforcing process under severe reforiaing conditions.

   During the first 1 1 hCU. The second process is characterized by a speed of entry: nt do 1 / 100oC approximately per 1eU! 'E1' isd3 .. e that the temperature must be increased, by i G for 100 1: e3 "in order to integrate the transformation into gasoline

 <Desc / Clms Page number 18>

 
 EMI18.1
 having an index V.i45Ft <$ net of 100. This corresponds to a period of use of 2,800 hours at least with a decrease in. round. in liquid in 5- which is little more than 2 per cent. fly for 2 Boa er, -as.

   When the solar ratio llYd “DzènotL! YocaZ'DUI.” 6t decreases to a value of 6 at the end. of 1,403 hours. -CI * r'o1'ffi3, ge .. the crushing speed only ausmwnte.: RpnL. The zrraphlque dô figure z shows the remarkable return stability of the-; pres-cnt. low pressure refracted prooéda ge and under very severe conditions using the p2¯ catallisour: e-r 3 .., t supported. The amount of liquid product Ce decreases 7d.e less than one percent by volume during 2200 hours of operation.
 EMI18.2
 



  The reforsaso process using the catalyst comprising platinum sana rhéniua; COn :: J3 we see in figure 2 presented a high speed of encrasscRent exceptloPJle21eDant which indicates a rapid deactivation of the catalysts In addition ^ .ar .. we see in figure 3 the liquid product e obtained during the process reforming using the co2 catalyst Pr <; Ml1t of 53..ne without rhenium significantly decreases dm-ant only a period of Enrche of 400 hours. Thus, the S / f ^ liquidated product obtained during the reorganization process using the 2 volume percent platinum catalyst during the 1: -oa hours of operation in the operation.



  It emerges from the above example that the low-pressure raror5e process of the present invention can be successfully onatioùl1er. 1) .11.0 i1l'6rioUle pressure at:! 7 bars osivîro.1 ¯ ¯ -: o3z 0, -u at he-ne space speed up5icure at 2? J3 ,, -.> '- ¯ï' produce 2 3 ± -... ". =. Sa '3 There' cc-index =.; ... ^ high tE3; C'G''v '.. çi :: t3 of 1esscnGc having an octane number of at E "i) ins 90J' and that the process is car.:<.ot0ri$é by a period of Da1 "cho of at least 2 & 00 hours with usa drop in the rtereēvra. in liquid in C5 + which is not greater than. 2 poroe hundred in volusa for 2000 hours.



  Katurelles3ntt the invention is not 11cltée to the embodiments described and shown and is likely to receive various variants within its scope and in the good spirit,

 <Desc / Clms Page number 19>

 LEGEND OF THE DRAWINGS
 EMI19.1
 
<tb>
<tb> Figures <SEP> Landmarks
<tb> 1 <SEP> A <SEP> Molar <SEP> ratio <SEP> H2 / HC
<tb> 1 <SEP> B <SEP> Temperature <SEP> (X) <SEP> to <SEP> which <SEP> 95% <SEP> in <SEP> volume
<tb> of the <SEP> naphtha <SEP> are <SEP> distilled <SEP> for <SEP> a
<tb> distillation <SEP> ASTMD-86,

   <SEP> C
<tb> 1 <SEP> C <SEP> Platinum <SEP> catalyst <SEP>
<tb>
 
 EMI19.2
 1 D Curve 4 Octane number 102 1 E 1t 3 'If tt 100
 EMI19.3
 
<tb>
<tb> 1 <SEP> F <SEP> "<SEP> 2 <SEP>" <SEP> "<SEP> 98
<tb> 1 <SEP> G <SEP> - <SEP> "<SEP> 1 <SEP>" <SEP> "<SEP> 98
<tb> 1 <SEP> H <SEP> Platinum-rhenium <SEP> <SEP> catalyst
<tb> 2 <SEP> I <SEP> Average temperature <SEP> <SEP> of the <SEP> catalyst <SEP> C
<tb> 2 <SEP> J <SEP> Hours <SEP> of <SEP> on
<tb> 2 <SEP> K <SEP> Platinum <SEP> catalyst <SEP>
<tb> 2 <SEP> L <SEP> '<SEP> Platinum-rhenium <SEP> <SEP> catalyst
<tb> 3 <SEP> M <SEP> Product <SEP> liquid <SEP> (C5 +)% <SEP> in <SEP> volume
<tb> 3 <SEP> N <SEP> Hours <SEP> of <SEP> on
<tb> 3 <SEP> 0 <SEP> Platinum-rhenium <SEP> <SEP> catalyst
<tb> 3 <SEP> P <SEP> Platinum <SEP> catalyst <SEP>
<tb>
 
 EMI19.4
 NOTE OF = -20C + 32

 

Claims (1)

CLAIMS 1.- A process for the catalytic reforming of a naphtha in order to obtain a reforming product having a net octane number of at least 98, which consists in contacting a naphtha and hydrogen with a catalyst comprising a porous inorganic oxide as a vehicle containing 0.01 to 1.0 percent by weight platinum activated by 0.01 to 2 percent by weight rhenium under reforming conditions comprising a pressure of less than about 17 bar gauge , an hourly liquid space velocity of at least 2.0, and a molar ratio to hydrogen / hydrocarbon (H2 / HC) less than the value determined by the equation log H2, 0062X - log 2 / HC = 0, 0062x- k where x is the temperature in F at which 95 volume percent of naphtha is distilled during distillation according to the method ASTM D-86, and where k depends on the net octane number (1.0.) Of the reforming product in production following Equation: k = -0.038 (1.0.) + 5.10 in which the run is continued for at least 2,000 hours with a drop in C5 + liquid yield of not more than 2 volume percent for 2,000 hours. 2. - The method of claim 1, wherein the naphtha is substantially free of sulfur. 3. - The method of claim 1, wherein the naphtha is a hyacracked naphtha. 4. The method of claim 1, wherein the vehicle contains 0.2 to 1 weight percent platinum, and 0.1 to 1.5 weight percent rhenium. 5. - The method of claim 1, wherein the hourly liquid space velocity this between 2 and 6. 6. - Process according to .revendication 1, in which the pressure is at least about 5.2 bars at the manometer, but is less than about 17 bars at the manometer. 7. - The method of claim 1, wherein the porous inorganic oxide serving as the vehicle is alumina. 8. The process of claim 1, wherein the naphtha is reformed to obtain a reforming product having a net octane number of at least 100. 9. A method according to claim 1, wherein the temperature at which 95 volume percent of the naphtha is <Desc / Clms Page number 21> distilled during an ASTM D-86 distillation is between 149 and 204 C. 10, - Process. according to claim 9, wherein the temperature is between 160 and 193 C. 11. - Process for the catalytic reforming of a naphtha, the temperature at which it distils at a rate of 95% by volume during an ASTM D-86 distillation is approximately 171 to 188 C, in order to obtain a A reforming product having a net octane number of at least 98, in which the execution is continued for at least 2,000 hours with a decrease in the yield of C5 + liquid which: ! 2 is no more than 2 percent by volume for 2,000 hours, and the naphtha and hydrogen are contacted with a catalyst comprising a porous inorganic oxide as a vehicle containing 0.01 to 1.0 percent. one hundred by weight platinum activated by 0.01 to 2 weight percent rhenium under reforming conditions comprising a pressure less than about 17 bars gauge, an hourly liquid space velocity of at least 2.0, and a hydrogen / hydrocarbon molar ratio of at least 5.4 when it is desired to obtain a reforming product having a net octane number of 98 and increasing by approximately 2/3 of a mole of hydrogen per unit of octane number at as the octane number of the reforming product formed is increased from 98 to 104. 12. A method according to claim 11, wherein the vehicle is alumina. 13.- Process for the catalytic reforming of a naphtha, the temperature at which it distills at a rate of 95% by volume during an ASTM D-86 distillation is approximately 171 to 188 C, in order to obtain a A reforming product having a net octane number of at least 98, in which naphtha and hydrogen are contacted with a catalyst comprising a porous inorganic oxide as a carrier containing. 0.01 to 1.0 percent by weight platinum activated by 0.01 to 2 percent rhenium under reforming conditions comprising a pressure less than about 17 bar gauge., An hourly liquid space velocity of at least 2.0, the runtime being continued for at least 2600 hours with a drop in Ce + liquid yield of not more than 2 volume percent for 2600 hours, and in which the maximum number of moles of hydrogen per mole of hydrocarbon in the reaction zone necessary to obtain the long operating period which characterizes the process is 5, 4 then <Desc / Clms Page number 22> that it is desired to obtain a reforming product having a net octane number of 98 and is increased by about 2/3 of a mole of hydrogen per unit of octane number as the octane number of the product increases. of reforming formed is increased from 98 to 104.