CA1189814A - Catalytic reforming process - Google Patents
Catalytic reforming processInfo
- Publication number
- CA1189814A CA1189814A CA000402892A CA402892A CA1189814A CA 1189814 A CA1189814 A CA 1189814A CA 000402892 A CA000402892 A CA 000402892A CA 402892 A CA402892 A CA 402892A CA 1189814 A CA1189814 A CA 1189814A
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- Prior art keywords
- catalyst
- reactor
- rhenium
- platinum
- reactors
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G59/00—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha
- C10G59/02—Treatment of naphtha by two or more reforming processes only or by at least one reforming process and at least one process which does not substantially change the boiling range of the naphtha plural serial stages only
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Catalysts (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process wherein, in a series of reforming zones, or on-stream reactors, each of which contains a bed, or beds of catalyst, the catalyst in the leading reforming zones is constituted of supported platinum and a relatively low concentration of rhenium, the catalyst in the last re-forming zone, or reactor of the series, is constituted of platinum and a relatively high concentration of rhenium, and a swing reactor, also containing a supported platinum and rhenium catalyst, is manifolded so that it can be sub-stituted for any one of the on-stream reactors of the unit.
The upper portion of the swing reactor contains a catalyst constituted of platinum and a relatively low concentration of rhenium, and the lower portion of the reactor contains a catalyst constituted of platinum and a relatively high con-centration of rhenium. The amount of rhenium relative to the platinum on the catalyst in the last reactor and lower portion of the swing reactor is present in a weight ratio of rhenium:platinum of at least 1.5:1; preferably at least 2:1, and more preferably ranges from about 2:1 to about 3:1. The amount of rhenium relative to the platinum on the catalyst in the lead reactors and upper portion of the swing reactor is present in a weight ratio of rhenium:platinum of no more than about 1:1. The beds of catalyst in the several reactors are serially contacted with a hydrocarbon or naphtha feed, and hydrogen, at reforming conditions the feed flowing from one reactor of the series to the next, and serially through the upper and lower beds of the swing reac-tor, to produce a hydrocarbon or naphtha product of improved octane, and the product is withdrawn.
A process wherein, in a series of reforming zones, or on-stream reactors, each of which contains a bed, or beds of catalyst, the catalyst in the leading reforming zones is constituted of supported platinum and a relatively low concentration of rhenium, the catalyst in the last re-forming zone, or reactor of the series, is constituted of platinum and a relatively high concentration of rhenium, and a swing reactor, also containing a supported platinum and rhenium catalyst, is manifolded so that it can be sub-stituted for any one of the on-stream reactors of the unit.
The upper portion of the swing reactor contains a catalyst constituted of platinum and a relatively low concentration of rhenium, and the lower portion of the reactor contains a catalyst constituted of platinum and a relatively high con-centration of rhenium. The amount of rhenium relative to the platinum on the catalyst in the last reactor and lower portion of the swing reactor is present in a weight ratio of rhenium:platinum of at least 1.5:1; preferably at least 2:1, and more preferably ranges from about 2:1 to about 3:1. The amount of rhenium relative to the platinum on the catalyst in the lead reactors and upper portion of the swing reactor is present in a weight ratio of rhenium:platinum of no more than about 1:1. The beds of catalyst in the several reactors are serially contacted with a hydrocarbon or naphtha feed, and hydrogen, at reforming conditions the feed flowing from one reactor of the series to the next, and serially through the upper and lower beds of the swing reac-tor, to produce a hydrocarbon or naphtha product of improved octane, and the product is withdrawn.
Description
1 BACI~GROUND OF TEIE INVE~NTION AND PRIOR ART
2 Catalytic reforming, or hydroforming, is a well~
3 established lndustrial process employed by the petroleum in-
4 clustry for improving the octane quality of naphthas or
5 straight run gasolines. In reforming, a multi-functional
6 catalyst is employed which contains a metal hydrogenation-
7 dehydrogenation (hydrogen transfer) component, or components,
8 substantially atomically dispersed upon the surface of a
9 porous, inorganic oxide support, notably alumina. Noble
10 metal catalysts, notably of the platinum type, are currently
11 employed, reforming being defined as the total effect of the
12 molecular changes, or hydrocarbon reactions, produced by
13 dehydrogenation of cyclohexanes and dehydroisomerization of
14 alkylcyclopentanes to yield aromatics; dehydrogenation of
15 paraffins to yield olefins; dehydrocyclization of paraffins
16 and olefins to yield aromatics; isomerization of n-paraffins;
17 isomerization of alkylcycloparaffins to yield cyclohexanesi
18 isomerization of substituted aromatics; and hydrocracking of
19 paraffins which produces gas, and inevitably coke, the lat-
20 ter being deposited on the catalyst.
21 Platinum has been widely commercially used in re-
22 cent years in the production of reforming catalysts, and
23 platinum-on-alumina catalysts have been commercially employed
24 in refineries for the last few decades. In the last decade,
25 additional metallic components have been added to platinum as
26 promotors to further improve the activity or selectivity, ox
27 both, of the basic platinum catalyst, e.q., iridium, rhenium,
28 tin, and the like. Some catalysts possess superior activity,
29 or selectivity, or both, as contrasted with other catalysts.
30 Platinum-rhenium catalysts by way of example possess admira-
31 ble selectivity as contrasted with platinum catalysts, se-
32 lectivity being defined as the ability of the catalyst to
33 produce high yields of C5+ liquid products with concurrent
34 low production of normally gaseous hydrocarbons, i~e., meth-
35 ane and other gaseous hydrocarbons~ and coke.
36 In a conventional process, a series of reactors
37 constitute the heart of the reformlng unit. Each reforming ~98~
1 reactor is generally provided with fixed beds of the cata-2 lyst ~hich receive upflow or downflow feed, and each is pro-3 vided wi-th a heater, because the reactions which take place 4 are endothermic. A naphtha feed, with hydrogen, or hydro-5 gen recycle gas, is concurrently passed through a preheat 6 furnace and reactor, and then in sequence through subsequent 7 interstage heaters and reactors of the series. The product 8 from the last reactor is separated into a liquid fract~on, 9 and a vaporous effluent. The latter is a gas rich in hydro-10 gen, and usually contains small amounts of normally gaseous 11 hydrocarbons, from which hydrogen is separated from the Cs+
12 liquid product and recycled to the process to minimi~e coke 13 production.
14 The activity of the catalyst gradually declines 15 due to buildup of cokc. Coke formation is helieved to result 16 from the deposition of coke precursors such as anthracene, 17 coronene, ovalene and other condensed ring aromatic molecules 18 on thc catalyst, these polymerizing to form coke. ~uring 19 operation, the temperature of the process is gradually raised 20 to compensate for the activity loss caused by the coke depo-21 sition. Eventually, however, economics dictate the neces-22 sity of reactivating the catalyst. Consequently, in all pro-23 cesses of this type the catalyst must necessarily be peri-24 odically regenerated by burning the coke off the catalyst at 25 controlled conditions, this constituting an initial phase of 26 catalyst reactivation.
27 Two major types of reforming are generally practic-28 ed in the multi-reactor units, both of which necessitate 29 periodic reactivation of the catalyst, the initial sequence 30 of which requires regeneration, i.e., burning the coke from 31 the catalyst. Reactivation of the catalyst is then complet 32 ed in a sequence of steps wherein the agglomerated metal hy-33 drogenation-dehydrogenation components are atomically re-34 dispersed. In the semi-regenerative process, a process of 35 the first type, the entire unit is operated by gradually and 36 progressively increasing the temperature to maintain the 37 activity of the catalyst caused by the coke deposition, until
1 reactor is generally provided with fixed beds of the cata-2 lyst ~hich receive upflow or downflow feed, and each is pro-3 vided wi-th a heater, because the reactions which take place 4 are endothermic. A naphtha feed, with hydrogen, or hydro-5 gen recycle gas, is concurrently passed through a preheat 6 furnace and reactor, and then in sequence through subsequent 7 interstage heaters and reactors of the series. The product 8 from the last reactor is separated into a liquid fract~on, 9 and a vaporous effluent. The latter is a gas rich in hydro-10 gen, and usually contains small amounts of normally gaseous 11 hydrocarbons, from which hydrogen is separated from the Cs+
12 liquid product and recycled to the process to minimi~e coke 13 production.
14 The activity of the catalyst gradually declines 15 due to buildup of cokc. Coke formation is helieved to result 16 from the deposition of coke precursors such as anthracene, 17 coronene, ovalene and other condensed ring aromatic molecules 18 on thc catalyst, these polymerizing to form coke. ~uring 19 operation, the temperature of the process is gradually raised 20 to compensate for the activity loss caused by the coke depo-21 sition. Eventually, however, economics dictate the neces-22 sity of reactivating the catalyst. Consequently, in all pro-23 cesses of this type the catalyst must necessarily be peri-24 odically regenerated by burning the coke off the catalyst at 25 controlled conditions, this constituting an initial phase of 26 catalyst reactivation.
27 Two major types of reforming are generally practic-28 ed in the multi-reactor units, both of which necessitate 29 periodic reactivation of the catalyst, the initial sequence 30 of which requires regeneration, i.e., burning the coke from 31 the catalyst. Reactivation of the catalyst is then complet 32 ed in a sequence of steps wherein the agglomerated metal hy-33 drogenation-dehydrogenation components are atomically re-34 dispersed. In the semi-regenerative process, a process of 35 the first type, the entire unit is operated by gradually and 36 progressively increasing the temperature to maintain the 37 activity of the catalyst caused by the coke deposition, until
38 finally the entire unit is shut down for regeneration, and 1 reactivation; of the catalyst. In the second, or cyclic 2 type oE process, -the reactors are individually isolated, or 3 in effect swung out of line by various manifolding arrange-4 ments, motor operated valving and the li]ce. The catalyst 5 is regenerated to remove the coke deposits, and then re-6 activated while the other reactors of the series remain on 7 stream. A "swing reactor" temporarily replaces a reactor 8 which is removed from the series for regenera-tion and reac-9 tivation of the catalyst, until it is put back in series.
Various improvements have been made in these pro-11 cesses to improve the performance of reforming catalysts in 12 order to reduce capital investment or improve Cs~ liquid 13 yields while improving the octane quality of naphthas and 14 straight run gasolines. New catalysts have been developed, 15 old catalysts haye been modified, and process conditions 16 have been altered in attempts to optimize the catalytic con-17 tribution of each charge of catalyst relative to a selected 18 performance objective. Nonetheless, while any good commer-19 clal reforming catalyst must possess good activity, activity 20 maintenance and selectivity to some degree, no catalyst can 21 possess even one, much less all of these properties to the 22 ultimate degree. Thus, one catalyst may possess relatively 23 high activity, and relatively low selectivity and vice versa.
24 ~nother may possess good selectivity, but its selectivity 25 may be relatively low as regards another catalyst. Platinum-26 rhenium catalysts~ among the handful of successful commer-27 cially known catalysts, maintain a rank of eminence as re-28 gards their selectivity; and they have good activity. None-29 theless, the existing worldwide shortage in the supply of 30 high octane naphtha persists and there is little likelihood 31 that this shortage will soon be in balance with demand. Con-32 sequently, a relatively small increase in the C5~ liquid 33 yield can represent a large credit in a commercial reforming 3~ operation.
Variations have been made in the amount, and kind 36 of catalysts charged to the different reforming reactors of 37 a series to modify or change the nature of the product, or 1 to improve C5~ liquid yleld. ~eference is made to published 2 ~. K. Application 2060682~ which presents a survey of such 3 prior art. Needless to say, however, albeit these varia-4 tions, and modifications have generally resulted in improv-5 ing the process with respect to one selected performance ob-6 ~ective, or another, present refinery economics require new 7 and improved processes which are capable of achieving higher 8 conversions of the product to C5~ liquid naphthas as con-9 trasted with present reforming operations.
A response to this demand embodies a process des-11 cribed in said published U. K. Appliation 2060682~, wherein, 12 in a series of reforming zones, or reactors, each of which 13 contains a bed, or beds of catalyst, the catalyst in the 14 leading reforming zones is constituted of supported plati-15 num and a relatively low concentration of rhenium, and in the 16 las-~ reforming zone, or reactor of the series, the catalyst 17 is constituted of platinum and a relatively high concentra-18 tion of rhenium. The amount of rhenium relative to the 19 platinum in the catalyst contained in the last reforming zone, 20 or reactor, is in fact present in an atomic ratio of rhenium:
21 platinum of at least about 1.5:1 and higher, and preferably 22 the atomic ratio of rhenium:platinum ranges at least about 23 2:1, and higher, and more preferably from about 2:1 to about 24 3:1. The leading reforming zones, or reactors of the series, 25 are provided with platinum-rhenium catalysts wherein the 26 atomic ratio of the rhenium:platinum ranges from about 0.1:1 27 to about 1:1, preferably from about 0.3:1 to about 1:1. In 28 carrying out the operation, the beds of catalyst are con-29 tacted with a hydrocarbon or naphtha feed, and hydrogen, at 30 reforming conditions to produce a hydrocarbon~ or naphtha 31 product of improved octane, and the product is withdrawn.
32 It is known that the amount of coke produced in an 33 operating run increases progressively from a leading reactor 34 to a subsequent reactor, or from the first reactor to the 35 last, or tail reactor of the series as a consequence of the 36 different types of reactions that predominate in the several 37 different reactors. Thus, in -the first reactor of the series 8~
the metal site, or hydrogenation-dehydrogenation component of the catalyst, plays a domi~ant role and the predominank reaction in-volves the dehydrogenation of naphthenes to aromatics. This re-action proceeds at relatively low temperature, and the coke forma-tion is relatively low. In the intermediate reactors (usually a second and -third reactor), on the other hand, the acid site plays an important role in isomerizing paraffins and naphthenes, and the additional naphthenes are dehydrogenated to aromatics as in the fi.rst reactor. In both of the intermediate reactors the temperature is ~aintained higher than in the first reactor, and the temperature in the third reactor is maintained hi.gher than that of the second reactor of the series. Carbon formation is higher in these reactors than in the first reactor of the series, and coke is higher in the third reactor than in the second reactor of the seriesO The chief reaction in the last, or tail reactor of the series involves dehydrocyclization of paraffins, and the highest temperature is employed in this reactor. Coke formation is highest in this reactor, and the reaction is often the most difEicult to control. It is also generally known that these in-creased levels of coke in the several reactors of the seriescauses considerable deactivation of the catalysts. Whereas the relationship betweén coke formation, and rhenium promotion to in-crease catalyst selectivity is not known with any degree of certainty because of the extreme complexity of these reactions, it is believed that the presence of the rhenium minimizes the ad-verse consequences of the increased coke levels, ableit it does not appear to minimize coke formation in any absolute sense.
Nonetheless, the concentration of the rhenium is increased in those reactors where coke formation is the greatest, but most particularly in the last reactor of the series. Thus, in one of its forms, the catalysts within the series of reactors are pro-gressively staged with respect to the rhenium concentration r the rhenium concen~ration being increased from the first to the last reactor of the series such that the rhenium content of the ~9~1~
platinum-rhenium catalysts is varied significantly to counteract the normal effects of coking.
In cyclic reforming, typically three or four reactors are arranged ln series, and a swing reactor is manifolded in the unit such that it can occupy any position in the reactor train as reactors are taken out of service and the catalyst regenerated, and reactivated. Thus, in a typical catalyst regeneration, re-activation sequence in a reactor series, four reactors and a swing reactor, the swing reactor spends less than about twenty-five per-cent oE the time in the first two reactor positions of the series, while in the remaining period the swing xeactor occupies either the third or last reactor position. The last reactor of the series remains on oil about seventy percent of the time. In practicing the process wherein high rhenium is concentrated within the platinum-rhenium catalyst of the last reactor of the series, and staged in progressively higher concentration in the other reactors with highest rhenium concentration within the last re-actor of the series, it may appear advantageous to substitute a high rhenium platinum-rhenium catalyst in a reactor occupying the last position of the series when this reactor is off oil for re-generation, and reactivation of the catalyst. However, placing a high rhenium platinum-rhenium catalyst in the swing reactor serves no useful purpose in the overall operation, and in fact results in significant C5+ liquid yield loss when the swing reactor occupies the first two positions as is required in conventional operations.
It is, nonetheless, the primary object of the present invention to provide a new and further-improved process, parti-cularly one which will provide enhanced C5~ liquid yield, catalyst activity and catalyst activity maintenance credits.
This object and others are achieved in improvements in a process for reforming naphtha, with hydrogen, in a cyclic reform-ing unit which contains a plurality of platinum-rhenium catalysts containing on-stream reactors in series, and a plati~um-rhenium catalyst containinq swing reactor manifolded therewith which can be periodically placed in series and substituted or an on-stream reactor while the latter is removed from series for regeneration and reactivation of the catalyst. The initial and intermediate on-stream reactors of the series each contain a bed, or beds, of catalyst constituted of supported platinum and a relatively low concentration of rhenium, the last on-stream reforming reactor of the series contains a catalyst constituted of platinum and a rela-tively high concentration of rhenium, and the swing reactor con-tains multiple beds of catalysts, on the entry side, an upper bed which contains catalyst constituted of supported platinum and a relatively low concentration of rhenium and, on the exit side, a lower bed which contains catalyst constituted of supported pla-tinum and a relatively high concentration of rhenium. The amount of rhenium relative to the platinum in the last reforming reactor, and in the lower bed of the swing reactor, is present in a weight ratio of at least about 1.5:1 and higher, more preferably from about 2:1 to about 3:1. Preferably, the amount of rhenium rela-tive to the platinum in the initial and intermediate on-stream reactors of the series, and upper bed of the swing reactor, are provided with platinum-rhenium catalyst wherein the weight ratio of rhenium:platinum ranges from about 0.1:1 to about 1:1, and preferably from about 0.3:1 to about 1:1, most preferably from about 0.5:1 to about 1:1. The beds of catalyst in the several reactors, inclusive of the swing reactor are serially contacted with a hydrocarbon or naptha feed, and hydrogen, at reforming conditions the feed flowing from one reactor of the series to the next, serially through the upper and lower beds of the swing re-actor, to produce a hydrocarbon, or naphtha product of improvedoctane, and the product is withdrawn.
Staged system credits in selectivity, catalyst activity and catalyst actlvity maintenance are provided by the use of a swing reactor containing an upper fixed bed of platinum-rhenium catalyst having a relatively low concentration ~89~
1 oE rhenium:platinum, and a lower fi~ed bed of platinum-2 rllenlum catalyst h~ving a relatively high concentration of 3 rhenium:platinum. Suitably, the upper bed reactor contains 4 from about 50 to about 90 percent, preferably from about 70 5 percent to about 85 percent of the catalyst, based on the 6 weight of catalyst in the reactor; the balance of the cata-7 lyst (50 percent to 10 percent, preferably 30 percent to 15 8 percent) being contained in the lower bed, or beds, of the 9 reactor. When the swing reactor is in the position of the 10 first or second of the on-stream reactors, the endotherm is 11 sufficient to minimize cracking reactions in the lower zone 12 of the reactor, thereby sUpprecsing Cs+ liquid yield loss.
13 On the other hand, in the last and second to last on-stream 14 positions, the high concentration of rhenium in the lower 15 bed, ox beds, is beneficial in improving coke tolerance at 16 the elevated temperatures.
17 These features and others will be better understood t 18 by reference to the following more detailed description~of the 19 invention, and to the drawing to which reference is made.
In the drawing:
21 The FIGURE depicts, by means of a simplified flow 22 diagram, a preferred cyclic reforming unlt inclusive of mul-23 tiple on-stream reactors, and an alternate or swing reactor 24 inclusive of manifolds for use with catalyst regeneration and 25 reactivation equipment (not shown).
26 Referring generally to the FIGURE, there is des-27 cribed a cyclic unit comprised of a multi-reactor system, 28 inclusive of on-stream Reactors A, B, C, D, and a swing Re-29 actor S, and a manifold useful with a facility for periodic 30 regeneration and reactivation of the catalyst of any given 31 reactor, swing Reactor S being manifolded to Reactors A, B~
32 C, D so that it can serve as a substitute reactor for pur-33 poses of regeneration and reactivation of the catalyst of a34 reactor taken off-stream. The several reactors of the 35 series A, B, C, D, are arranged so that while one reactor 36 is off-stream for regeneration and reactivation of the cata-37 lyst, the swing Reactor S can replace it and provision is ~89~
1 also made for regeneration and reactivation of the catalyst 2 of the swin~ reactor.
3 In particular, the on-~tream Reactors A, B, C, D, 4 each of which is provided with a separate furnace or heater, 5 FA, or rehea-ter FB, Fc, FD, respectively, are connected in 6 series via an arrangement of connecting process piping and 7 valves so that feed can be passed in seratim through FAA, 8 FBB, E`CC, FDD, respectively; or generally similar grouping 9 wherein any of Reactors A, B, C, D are replaced by ~eactor S.
10 This arrangement of piping and valves is designated by the 11 numeral 10. Any one of the on-stream Reactors A, B, C, D, 12 respectively, can be substituted by Swing Reactor S as when 13 the catalyst of any one of the former requires regeneration 14 and reactivation. This is accomplished in "paralleling" the 15 swing reactor with the reactor to be removed from the cir-16 cuit for regeneration by opening the valves on each side of 17 a glven reactor which connect to the upper and lower lines 18 of swing header 20, and then closing off the valves in line 19 10 on both sides of said reactor so that fluid enters and 20 exits from said swing Reactor S. ~egeneration facilities, 21 not shown, are manifolded to each of the several Reactors A, 22 B, C, D, S through a parallel circuit of connecting piping 23 and valves which form the upper and lower lines of regenera-24 tion header 30, and any one of the several reactors can be 25 individually isolated from the other reactors of the unit and 26 the catalyst thereof regenerated and reactivated.
27 In conventional practice the reactor regeneration 28 sequence is practiced in the order which will optimize the 29 efficiency of the catalyst based on a consideration of the 30 amount of coke deposited on the catalyst of the different 31 reactors during the operation. Coke deposits much more 32 rapidly on the catalyst of Reactors Cr D, and S than on the 33 catalyst of Reactors A and B and, accordingly, the catalysts 34 of the former are regenerated and reactivated at greater 35 frequency than the latter. The reactor regeneration sequence 36 is characteristically in the order ACDS/BCDS, i.e., Reactors 37 A, C, D, B, etc., respectively, are substituted in order by ~39~
1 another reactor, typically swing Reactor S, and the cata-2 lyst thereof regenerated and reactivated while the other 3 four reactors are left on-stream.
4 l~ith reEerence to the FIGURE, for purposes of 5 illustrating a catalyst regeneration, reactivation sequence, 6 it is assumed that all of Reactors A, B, C, D and S were 7 charged ab initio with fresh presulfided catalyst, and Re-8 actors A, B, C, D then put on-stream. The catalyst of each 9 of the several Reactors A, B, C, D are then each removed 10 from the unit as the catalyst is deactivated, the catalyst 11 of each subsequently regenerated, and reactivated in conven-12 tional sequence, supra.
13 In conducting the reforming operations, substan-14 tially all or a major portion of the moisture is scrubbed, 15 or adsorbed from the hydrogen recycle gas which is returned 16 to the unit to maintain a dry system. The recycle gas of the 17 stream should be dried sufficiently such that it contains a 18 maximum of about 50 parts, preferably 20 parts, per million 19 parts of water.
/t' pl'DC ess The }~Y4~n, and its principle of operation, will 21 be more fully understood by reference to the following exam-22 ples, and comparative data, which characterizes a preferred 23 mode of operation.
In a first run, Reactors A, B, C, D and S were each 26 charged with a commercially supplied catalyst which contained 27 platinum and rhenium well dispersed upon the surface of a 28 gamma alumina support. The catalyst, Catalyst X, was dried, 29 calcined, and then sulfided by contact with an admixture of 30 n-butyl mercaptan in hydrogen, the gas having been injected 31 into the reactor to provide a catalyst (dry basis) of the 32 following weight composition, to wit:
33 Catalyst X
34 Platinum 0.3 wt.%
Rhenium 0.3 wt.
36 Chloride 0.9 wt.
37 Sulfur 0.07 wt.
38 Alumina Balance wt.
~:~L89~
1 In a second run, Reactors A, B and C were each 2 then charged with a portion of Catalyst X. Reactor D, and 3 the lower portion of Reactor S, were each then charged with 4 a catalyst, Catalyst Y, similar in all respects to Catalyst 5 X and similarly treated, except that Catalyst Y (dry basis) 6 was of the following composition:
7 Catalyst Y
8 Platinum 0.3 wt.%
9 Rhenium 0.67 wt.%
Chloride 1.1 wt.%
11 sulEur 0.15 wt.%
12 A]umina Balance wt.~
13 The upper portion of Reactor S, in the second run, 14 was charged with a portion of Catalyst X, the catalyst 15 charged to Reactors A, B, and C. The upper portion of Reac-16 tor S contained 70 wt.% of the total catalyst charge, and the 17 lower portion of Reactor S contained 30 wt.% o the total 18 catalyst char~e to the reactor.
19 The catalyst type charged to each reactor and the 20 fraction of the total catalyst charge, based on the weight 21 of the total catalyst in all reactors, the catalyst regenera-22 tion time required for each reactor in its respective posi-23 tion, and the equivalent isothermal temperature (E . I o T. ) in 24 each of the runs is given in Table 1.
Table 1 26 Reactor Catalyst Fraction Total Regeneration E.I.T.
27 Type_atalyst Charge Time F
28 A (Runs 1 & 2) X 0.131 24 860 29 B (Runs 1 & 2) X 0.217 24 917 30 C (Runs 1 & 2) X 0.217 36 952 31 D (Runs 1 & 2) Y 0.217 36 972 32 S (Run 1) X 0.217 36 function 33 of posi-3 tion 35 S (Run 2)70%X/30%Y 0.217 36 function 36 of posi-37 tion 38 Reforming runs were then initiatedf Reactors A, B,
Various improvements have been made in these pro-11 cesses to improve the performance of reforming catalysts in 12 order to reduce capital investment or improve Cs~ liquid 13 yields while improving the octane quality of naphthas and 14 straight run gasolines. New catalysts have been developed, 15 old catalysts haye been modified, and process conditions 16 have been altered in attempts to optimize the catalytic con-17 tribution of each charge of catalyst relative to a selected 18 performance objective. Nonetheless, while any good commer-19 clal reforming catalyst must possess good activity, activity 20 maintenance and selectivity to some degree, no catalyst can 21 possess even one, much less all of these properties to the 22 ultimate degree. Thus, one catalyst may possess relatively 23 high activity, and relatively low selectivity and vice versa.
24 ~nother may possess good selectivity, but its selectivity 25 may be relatively low as regards another catalyst. Platinum-26 rhenium catalysts~ among the handful of successful commer-27 cially known catalysts, maintain a rank of eminence as re-28 gards their selectivity; and they have good activity. None-29 theless, the existing worldwide shortage in the supply of 30 high octane naphtha persists and there is little likelihood 31 that this shortage will soon be in balance with demand. Con-32 sequently, a relatively small increase in the C5~ liquid 33 yield can represent a large credit in a commercial reforming 3~ operation.
Variations have been made in the amount, and kind 36 of catalysts charged to the different reforming reactors of 37 a series to modify or change the nature of the product, or 1 to improve C5~ liquid yleld. ~eference is made to published 2 ~. K. Application 2060682~ which presents a survey of such 3 prior art. Needless to say, however, albeit these varia-4 tions, and modifications have generally resulted in improv-5 ing the process with respect to one selected performance ob-6 ~ective, or another, present refinery economics require new 7 and improved processes which are capable of achieving higher 8 conversions of the product to C5~ liquid naphthas as con-9 trasted with present reforming operations.
A response to this demand embodies a process des-11 cribed in said published U. K. Appliation 2060682~, wherein, 12 in a series of reforming zones, or reactors, each of which 13 contains a bed, or beds of catalyst, the catalyst in the 14 leading reforming zones is constituted of supported plati-15 num and a relatively low concentration of rhenium, and in the 16 las-~ reforming zone, or reactor of the series, the catalyst 17 is constituted of platinum and a relatively high concentra-18 tion of rhenium. The amount of rhenium relative to the 19 platinum in the catalyst contained in the last reforming zone, 20 or reactor, is in fact present in an atomic ratio of rhenium:
21 platinum of at least about 1.5:1 and higher, and preferably 22 the atomic ratio of rhenium:platinum ranges at least about 23 2:1, and higher, and more preferably from about 2:1 to about 24 3:1. The leading reforming zones, or reactors of the series, 25 are provided with platinum-rhenium catalysts wherein the 26 atomic ratio of the rhenium:platinum ranges from about 0.1:1 27 to about 1:1, preferably from about 0.3:1 to about 1:1. In 28 carrying out the operation, the beds of catalyst are con-29 tacted with a hydrocarbon or naphtha feed, and hydrogen, at 30 reforming conditions to produce a hydrocarbon~ or naphtha 31 product of improved octane, and the product is withdrawn.
32 It is known that the amount of coke produced in an 33 operating run increases progressively from a leading reactor 34 to a subsequent reactor, or from the first reactor to the 35 last, or tail reactor of the series as a consequence of the 36 different types of reactions that predominate in the several 37 different reactors. Thus, in -the first reactor of the series 8~
the metal site, or hydrogenation-dehydrogenation component of the catalyst, plays a domi~ant role and the predominank reaction in-volves the dehydrogenation of naphthenes to aromatics. This re-action proceeds at relatively low temperature, and the coke forma-tion is relatively low. In the intermediate reactors (usually a second and -third reactor), on the other hand, the acid site plays an important role in isomerizing paraffins and naphthenes, and the additional naphthenes are dehydrogenated to aromatics as in the fi.rst reactor. In both of the intermediate reactors the temperature is ~aintained higher than in the first reactor, and the temperature in the third reactor is maintained hi.gher than that of the second reactor of the series. Carbon formation is higher in these reactors than in the first reactor of the series, and coke is higher in the third reactor than in the second reactor of the seriesO The chief reaction in the last, or tail reactor of the series involves dehydrocyclization of paraffins, and the highest temperature is employed in this reactor. Coke formation is highest in this reactor, and the reaction is often the most difEicult to control. It is also generally known that these in-creased levels of coke in the several reactors of the seriescauses considerable deactivation of the catalysts. Whereas the relationship betweén coke formation, and rhenium promotion to in-crease catalyst selectivity is not known with any degree of certainty because of the extreme complexity of these reactions, it is believed that the presence of the rhenium minimizes the ad-verse consequences of the increased coke levels, ableit it does not appear to minimize coke formation in any absolute sense.
Nonetheless, the concentration of the rhenium is increased in those reactors where coke formation is the greatest, but most particularly in the last reactor of the series. Thus, in one of its forms, the catalysts within the series of reactors are pro-gressively staged with respect to the rhenium concentration r the rhenium concen~ration being increased from the first to the last reactor of the series such that the rhenium content of the ~9~1~
platinum-rhenium catalysts is varied significantly to counteract the normal effects of coking.
In cyclic reforming, typically three or four reactors are arranged ln series, and a swing reactor is manifolded in the unit such that it can occupy any position in the reactor train as reactors are taken out of service and the catalyst regenerated, and reactivated. Thus, in a typical catalyst regeneration, re-activation sequence in a reactor series, four reactors and a swing reactor, the swing reactor spends less than about twenty-five per-cent oE the time in the first two reactor positions of the series, while in the remaining period the swing xeactor occupies either the third or last reactor position. The last reactor of the series remains on oil about seventy percent of the time. In practicing the process wherein high rhenium is concentrated within the platinum-rhenium catalyst of the last reactor of the series, and staged in progressively higher concentration in the other reactors with highest rhenium concentration within the last re-actor of the series, it may appear advantageous to substitute a high rhenium platinum-rhenium catalyst in a reactor occupying the last position of the series when this reactor is off oil for re-generation, and reactivation of the catalyst. However, placing a high rhenium platinum-rhenium catalyst in the swing reactor serves no useful purpose in the overall operation, and in fact results in significant C5+ liquid yield loss when the swing reactor occupies the first two positions as is required in conventional operations.
It is, nonetheless, the primary object of the present invention to provide a new and further-improved process, parti-cularly one which will provide enhanced C5~ liquid yield, catalyst activity and catalyst activity maintenance credits.
This object and others are achieved in improvements in a process for reforming naphtha, with hydrogen, in a cyclic reform-ing unit which contains a plurality of platinum-rhenium catalysts containing on-stream reactors in series, and a plati~um-rhenium catalyst containinq swing reactor manifolded therewith which can be periodically placed in series and substituted or an on-stream reactor while the latter is removed from series for regeneration and reactivation of the catalyst. The initial and intermediate on-stream reactors of the series each contain a bed, or beds, of catalyst constituted of supported platinum and a relatively low concentration of rhenium, the last on-stream reforming reactor of the series contains a catalyst constituted of platinum and a rela-tively high concentration of rhenium, and the swing reactor con-tains multiple beds of catalysts, on the entry side, an upper bed which contains catalyst constituted of supported platinum and a relatively low concentration of rhenium and, on the exit side, a lower bed which contains catalyst constituted of supported pla-tinum and a relatively high concentration of rhenium. The amount of rhenium relative to the platinum in the last reforming reactor, and in the lower bed of the swing reactor, is present in a weight ratio of at least about 1.5:1 and higher, more preferably from about 2:1 to about 3:1. Preferably, the amount of rhenium rela-tive to the platinum in the initial and intermediate on-stream reactors of the series, and upper bed of the swing reactor, are provided with platinum-rhenium catalyst wherein the weight ratio of rhenium:platinum ranges from about 0.1:1 to about 1:1, and preferably from about 0.3:1 to about 1:1, most preferably from about 0.5:1 to about 1:1. The beds of catalyst in the several reactors, inclusive of the swing reactor are serially contacted with a hydrocarbon or naptha feed, and hydrogen, at reforming conditions the feed flowing from one reactor of the series to the next, serially through the upper and lower beds of the swing re-actor, to produce a hydrocarbon, or naphtha product of improvedoctane, and the product is withdrawn.
Staged system credits in selectivity, catalyst activity and catalyst actlvity maintenance are provided by the use of a swing reactor containing an upper fixed bed of platinum-rhenium catalyst having a relatively low concentration ~89~
1 oE rhenium:platinum, and a lower fi~ed bed of platinum-2 rllenlum catalyst h~ving a relatively high concentration of 3 rhenium:platinum. Suitably, the upper bed reactor contains 4 from about 50 to about 90 percent, preferably from about 70 5 percent to about 85 percent of the catalyst, based on the 6 weight of catalyst in the reactor; the balance of the cata-7 lyst (50 percent to 10 percent, preferably 30 percent to 15 8 percent) being contained in the lower bed, or beds, of the 9 reactor. When the swing reactor is in the position of the 10 first or second of the on-stream reactors, the endotherm is 11 sufficient to minimize cracking reactions in the lower zone 12 of the reactor, thereby sUpprecsing Cs+ liquid yield loss.
13 On the other hand, in the last and second to last on-stream 14 positions, the high concentration of rhenium in the lower 15 bed, ox beds, is beneficial in improving coke tolerance at 16 the elevated temperatures.
17 These features and others will be better understood t 18 by reference to the following more detailed description~of the 19 invention, and to the drawing to which reference is made.
In the drawing:
21 The FIGURE depicts, by means of a simplified flow 22 diagram, a preferred cyclic reforming unlt inclusive of mul-23 tiple on-stream reactors, and an alternate or swing reactor 24 inclusive of manifolds for use with catalyst regeneration and 25 reactivation equipment (not shown).
26 Referring generally to the FIGURE, there is des-27 cribed a cyclic unit comprised of a multi-reactor system, 28 inclusive of on-stream Reactors A, B, C, D, and a swing Re-29 actor S, and a manifold useful with a facility for periodic 30 regeneration and reactivation of the catalyst of any given 31 reactor, swing Reactor S being manifolded to Reactors A, B~
32 C, D so that it can serve as a substitute reactor for pur-33 poses of regeneration and reactivation of the catalyst of a34 reactor taken off-stream. The several reactors of the 35 series A, B, C, D, are arranged so that while one reactor 36 is off-stream for regeneration and reactivation of the cata-37 lyst, the swing Reactor S can replace it and provision is ~89~
1 also made for regeneration and reactivation of the catalyst 2 of the swin~ reactor.
3 In particular, the on-~tream Reactors A, B, C, D, 4 each of which is provided with a separate furnace or heater, 5 FA, or rehea-ter FB, Fc, FD, respectively, are connected in 6 series via an arrangement of connecting process piping and 7 valves so that feed can be passed in seratim through FAA, 8 FBB, E`CC, FDD, respectively; or generally similar grouping 9 wherein any of Reactors A, B, C, D are replaced by ~eactor S.
10 This arrangement of piping and valves is designated by the 11 numeral 10. Any one of the on-stream Reactors A, B, C, D, 12 respectively, can be substituted by Swing Reactor S as when 13 the catalyst of any one of the former requires regeneration 14 and reactivation. This is accomplished in "paralleling" the 15 swing reactor with the reactor to be removed from the cir-16 cuit for regeneration by opening the valves on each side of 17 a glven reactor which connect to the upper and lower lines 18 of swing header 20, and then closing off the valves in line 19 10 on both sides of said reactor so that fluid enters and 20 exits from said swing Reactor S. ~egeneration facilities, 21 not shown, are manifolded to each of the several Reactors A, 22 B, C, D, S through a parallel circuit of connecting piping 23 and valves which form the upper and lower lines of regenera-24 tion header 30, and any one of the several reactors can be 25 individually isolated from the other reactors of the unit and 26 the catalyst thereof regenerated and reactivated.
27 In conventional practice the reactor regeneration 28 sequence is practiced in the order which will optimize the 29 efficiency of the catalyst based on a consideration of the 30 amount of coke deposited on the catalyst of the different 31 reactors during the operation. Coke deposits much more 32 rapidly on the catalyst of Reactors Cr D, and S than on the 33 catalyst of Reactors A and B and, accordingly, the catalysts 34 of the former are regenerated and reactivated at greater 35 frequency than the latter. The reactor regeneration sequence 36 is characteristically in the order ACDS/BCDS, i.e., Reactors 37 A, C, D, B, etc., respectively, are substituted in order by ~39~
1 another reactor, typically swing Reactor S, and the cata-2 lyst thereof regenerated and reactivated while the other 3 four reactors are left on-stream.
4 l~ith reEerence to the FIGURE, for purposes of 5 illustrating a catalyst regeneration, reactivation sequence, 6 it is assumed that all of Reactors A, B, C, D and S were 7 charged ab initio with fresh presulfided catalyst, and Re-8 actors A, B, C, D then put on-stream. The catalyst of each 9 of the several Reactors A, B, C, D are then each removed 10 from the unit as the catalyst is deactivated, the catalyst 11 of each subsequently regenerated, and reactivated in conven-12 tional sequence, supra.
13 In conducting the reforming operations, substan-14 tially all or a major portion of the moisture is scrubbed, 15 or adsorbed from the hydrogen recycle gas which is returned 16 to the unit to maintain a dry system. The recycle gas of the 17 stream should be dried sufficiently such that it contains a 18 maximum of about 50 parts, preferably 20 parts, per million 19 parts of water.
/t' pl'DC ess The }~Y4~n, and its principle of operation, will 21 be more fully understood by reference to the following exam-22 ples, and comparative data, which characterizes a preferred 23 mode of operation.
In a first run, Reactors A, B, C, D and S were each 26 charged with a commercially supplied catalyst which contained 27 platinum and rhenium well dispersed upon the surface of a 28 gamma alumina support. The catalyst, Catalyst X, was dried, 29 calcined, and then sulfided by contact with an admixture of 30 n-butyl mercaptan in hydrogen, the gas having been injected 31 into the reactor to provide a catalyst (dry basis) of the 32 following weight composition, to wit:
33 Catalyst X
34 Platinum 0.3 wt.%
Rhenium 0.3 wt.
36 Chloride 0.9 wt.
37 Sulfur 0.07 wt.
38 Alumina Balance wt.
~:~L89~
1 In a second run, Reactors A, B and C were each 2 then charged with a portion of Catalyst X. Reactor D, and 3 the lower portion of Reactor S, were each then charged with 4 a catalyst, Catalyst Y, similar in all respects to Catalyst 5 X and similarly treated, except that Catalyst Y (dry basis) 6 was of the following composition:
7 Catalyst Y
8 Platinum 0.3 wt.%
9 Rhenium 0.67 wt.%
Chloride 1.1 wt.%
11 sulEur 0.15 wt.%
12 A]umina Balance wt.~
13 The upper portion of Reactor S, in the second run, 14 was charged with a portion of Catalyst X, the catalyst 15 charged to Reactors A, B, and C. The upper portion of Reac-16 tor S contained 70 wt.% of the total catalyst charge, and the 17 lower portion of Reactor S contained 30 wt.% o the total 18 catalyst char~e to the reactor.
19 The catalyst type charged to each reactor and the 20 fraction of the total catalyst charge, based on the weight 21 of the total catalyst in all reactors, the catalyst regenera-22 tion time required for each reactor in its respective posi-23 tion, and the equivalent isothermal temperature (E . I o T. ) in 24 each of the runs is given in Table 1.
Table 1 26 Reactor Catalyst Fraction Total Regeneration E.I.T.
27 Type_atalyst Charge Time F
28 A (Runs 1 & 2) X 0.131 24 860 29 B (Runs 1 & 2) X 0.217 24 917 30 C (Runs 1 & 2) X 0.217 36 952 31 D (Runs 1 & 2) Y 0.217 36 972 32 S (Run 1) X 0.217 36 function 33 of posi-3 tion 35 S (Run 2)70%X/30%Y 0.217 36 function 36 of posi-37 tion 38 Reforming runs were then initiatedf Reactors A, B,
39 C and D having been placed on-stream with Reactor S in stand ~89~
1 by position, by adjusting the hydrogen and feed rates to the 2 reactors, the feed being characterized as a naphtha blend 3 which had, as shown in Table 2, the followin~ lnspections:
4 Table 2 5ASTM Distillation, F
6 Initial ~66 18 Final s.P. 358 19 Octane No., RON Clear 35.0 Gravity, API 58.9 21 Sulfur, Wt. ppm 0.5 22 ~nalysis, Vol. Percent 23 Paraffins 66.3 24 Naphthenes 22.7 Aromatics 11.0 26The temperature and pressure of the reactors in 27 each run were then adjusted to the operating conditions 28 required to produce a 100 RONC octane C5+ liquid product, and 29 the run was continued at generally optimum reforming condi-30 tions by adjustment of these and other major process vari-31 ables to those given below:
32 Major Operating VariablesProcess Conditions 33 Pressure Psig 175 34 Reactor Temp., E.I.T. F950 35 Recycle Gas Rate, SCF/B3000 36 lhe runs were continued until such time that suf-37 ficient coke had deposited on the catalyst of a reactor that - ]3 -1 regeneration, and reactivation of the catalyst of a given 2 reactor was required. Each reactor oE the series was peri-3 odically replaced in each run and the catalyst thereof re-4 generated, and reactivated for a time period as given in 5 Table 1. Reactors C and D, and Reactor S when placed in the 6 position of Reactors C and D, thus require 36 hours for re-7 generation and reactivation, whereas Reactors A and B require 8 24 hours. The regeneration in each instance was accomplished 9 by burning the co~e from the coked catalyst, initially by 10 burning at 950F by the addition of a gas which contained 11 0.6 mole percent oxygen; and thereafter the temperature was 12 maintained at 950F while the oxygen concentration in the 13 gas was increased to 6 mole percent. Reactivation in each 14 instance was conducted by the steps of: (a) redispersing 15 the agglomerated metals by contact of the catalyst with a 16 gaseous admixture containing sufficient carbon tetrachloride 17 to decompose in situ and deposit 0.1 wt.~ chloride on the 18 catalyst; (b) continuing to add a gaseous mixture containing 19 6% oxygen for a period of 2 to 4 hours while maintaining tem-20 perature of 950F; (c) purging with nitrogen to remove essen-21 tially all traces of oxygen from the reactor; and (d) reduc-22 ing the metals of the catalyst of contact with a hydrogen-23 containing gas at 850F.
24 In each instance after a regeneration/reactivation 25 sequence, the activation of the catalyst was completed by 26 sulfiding the catalyst of all of Reactors A, Bl C, D and S
27 by direct contact with a gaseous admixture of n-butyl mer-28 captan in hydrogen, sufficient to deposit 0.001-0.1 wt.%
29 sulfur on the catalyst.
Referring to Table 3 there is tabulated a conven-31 tional reactor regeneration sequence ACDS/BCDS, inclusive of 32 starting step "O" (Column 1~ wherein all of Reactors A, B, C, 33 and D are on-stream and serially aligned, with swing Reactor 34 S in standby, and eight additional steps, viz. steps 1 35 through 8, wherein Reactors A, C, D, S and B, C, D, S are 36 replaced one by one with swing Reactor S. The fourth column 37 of the table shows the time period each reactor remains off~
~ 14 -1 stream for ~e~eneration, and reactivation; a total of 264 2 hours.
3 Table 3 4 Reactors Reactor Time Required for On- Being Regeneration, and 6 Stream Regenerated Reactivation, Hours 11 4 ~ B C D S 36 16 Calculations show that in the cyclic re~orming 17 operation Reactor D is out of service for the required cata-18 lyst regeneratlon, and reactivation, 27~ of the total time 19 period. Conversely, Reactor D is in service 73% of the to-20 tal time period. Optimum benefits, however, can be achieved 21 only during the actual period when the high rhenium platinum-22 rhenium catalyst is fully utilized at the tail reactor posi-23 tion- This ideal condition, though it is not possible to 24 achieve 100~ of the time in a conventional cyclic reforming 25 operation, is represented in Table 4. Thus, ideally the use 26 of the high rhenium platinum-rhenium catalyst in the tail 27 reactor can provide a 15% activity credit and a 1.0% Cs+
28 liquid volume yield credit as contrasted with an operation 29 which employs a conventional platinum-rhenium catalyst, or 30 platinum-rhenium catalyst which contains an atomic ratio of 31 rhenium:platinum of 1:1 in all of the reactors of the unit.
32 In the normal cyc]ic reforming operation with the 33 full benefits of the high rhenium platinum-rhenium catalyst 34 utilized 73% of the period, and lost during the 27% of the 35 period when a swing Reactor S containing a platinum-rhenium 36 catalyst having an atomic ratio of rhenium:platinum of 1:1 37 i~s swung on line, the overall advantage a~ shown by reference 38 to Table 4 is reduced to a 12% activity credit and a 0.8%
39Cs+ liquid volume yield credit.
In accordance with thls new process, howevex, as further shown by reference to Table ~, an activity creclit of 14~ and a 0.9% C5~ liquid volume percent yield credit are obtained. These advantages result because the ~igh rhenium platinum-rhenium catalyst is utilized more effectively, and to a greater extent of time in the D reactor position. In both the C and D reactor positions the high rhenium-platinum-rhenium catalyst of swing Reactor S provides some advantages, even if maximum utilization is not possible. Moreover, the lower catalyst bed o swing Reactor S of the present invention takes advanta~e of the endo-therm which normally occurs in the bottom portion of a reactor in the A and B positions, this preventing yield loss by cracking such as has been observed with high rhenium platinum-rhenium catalysts employed in lead reactor positions (i.e., swing reactor charged with 100% high rhen~ium platinum-rhenium catalysts).
Table 4 950 F overall E.I.T.; 175 Psig; 3000 SCF/B
Case Credits Activity C Yield Ideal + 15~ + 1.0 LV %
Normal Cyclic Operation+ 12% + 0.8 LV %
This process + 14% + 0.9 LV %
The present new process, thus affords a much closer approach to the ideal than possible in normal cyclic reforming reactions.
In one of its aspects, optimum utilization of rhenium-promoted pla~inum catalysts is obtained by providing the catalyst of the initial, or first reactor of the series with rhenium in concentration adequa~e to provide an atomic ratio of rhenium:
platinum ranging from about 0.1:1 to about 0.5:1, preferably from about 0.3:1 to about 0.5:1. The catalyst of the intermediate re-forming zones, as represented by the reactors intermediate between the first and last reac~ors of the series, and the entry side of the swing reactor are provided with rhenium in ' f' concentration adequate to provide a weight ratio of rhenium:
platinum ranging from about 0.5:1 to about 1:1, preferably above 0,5:1 to about 0.8:1. The last reactor of the series and exit side of the swing reactor are provided with rhenium in concentra-tion adequate to provide a weight ratio of rhenium:platinum from about 1.5:1 to about 3:1, preferably from about 2:1 to about 3:1.
The last reactor of a series, whether the series contains less than three or more than three reactors, and the lower portion of the swing reactor are always provided with a catalyst which contains a weight ratio of rhenium:platinum of at least 1~:1 and preferably contains a weight ratio of rhenium:platinum ranging from about 2:1 to about 3:1.
The catalyst employed in accordance with this new process is necessarily constituted of composite particles which contain, besides a carrier or support material, a hydrogenation-dehydro-genation component, or components, a halide component and, pre-ferably, the catalyst is sulfided. The support material is constituted of a porous, refractory inorganic oxide, particularly alumina. The support can contain, e.g., one or more of alumina, bentonite, clay, diatomaceous earth, ~eolite, silica, activated carbon, magnesia, 2irconia, thoria, and the like; though the most preferred support is alumina to which, if desired, can be added a suitable amount of other refractory carrier materials such as silica, zirconia, magnesia, titania, etc., usually in a range of about 1 to 20 percent, based on the weight of the support. A
preferred support for the practice of the present invention is one having a surface area of more than 50 m2/g, preferably from about 100 to about 300 m2/g, a bulk density of about 0.3 to 1.0 g/ml, preferably about 0.4 to 0.8 g/ml, an average pore volume of about 002 to 1.1 ml/g, preferably about 0.3 to 0.8 ml/g, and an average pore diameter of about 30 to 300 A.
The metal hydrogenation-`dehydrogenation component can be composited with or otherwise intimately associated with the porous inorganic oxide support or carrier by var-1 ious techniques known to the art such as ion-exchange, co-2 precipitation with the alumina in the sol or gel form, and 3 the li~e. For example, the catalyst composi-te can be formed 4 by adding together suitable xeagents such as a salt of plat-5 lnum and ammonium hydroxide or carbonate, and a salt of alu-6 minùm such as aluminum chloride or aluminum sulfate to form 7 aluminum hydroxide. The aluminum hydroxide containing the 8 salts of platinum can then be heated, dried, formed into 9 pellets or extruded, and then calcined in nitrogen or other 10 non-agglomerating atmosphere. The metal hydrogenation com-11 ponents can also be added to the catalyst by impregnation, 12 typically via an "incipient wetness" technique which re 13 quires a minimum of solution so that the total solution is 14 absorbed, initially or after some evaporation~
It is preferred to deposit the platinum and rhen-16 ium metals, and additional metals used as promoters, if any, 17 on a previously pilled, pelleted, beaded, extruded, or 18 sieved particulate support material by the impregnation 19 method. Pursuant to the impregnation method, porous refrac-20 tory inorganic oxides in dry or solvated state are contacted, 21 either alone or admixed, or otherwise incorporated with a 22 metal or metals-containing solution, or solutions, and there-23 by impregnated by either the "incipient wetness" technique, 24 or a technique embodying absorption from a dilute or concen-25 trated solution, or solutions, with subsequent filtration 26 or evaporation to effect total uptake of the metallic com-27 ponents.
28 Platinum in absolute amount, is usually supported 29 on the carrier within the range of from about 0.01 to 3 per-30 cent, preferably from about 0.05 to 1 percent, based on the 31 weight of the catalys-t (dry basis). Rhenium, in absolute 32 amount, is also usually supported on the carrier in concen-33 tration ranging from about 0.1 to about 3 percent, prefer-34 ably from about 0.5 to about 1 percent, based on the weight 35 of the catalyst (dry basis). The absolute concentration of ; 36 each, of course, is preselected to provide the desired atomic ~ o~ w~ tt /~t~o~
'`A 37 ratio~of rhenium:platinum for a respective reactor of the 38 unit, as heretofore expressed. In the tail reactor, and e~l~s~
1 ~-~t-}~n of the swiny reactor, the rhenium is pro-2 vided in major amount relative to the platinum whereas, in 3 contrast, in all other reactors and upper portion of the 4 swing reactor the rhenium is provided in minor amount, or 5 no more than about an equal amount, relative to the plati-6 num, based on the atomi-~ weight of these metals, one with 7 respect to the other. In compositiny the metals with the 8 carrier, essentially any soluble compound can be used, but 9 a soluble compound which can easily be subjected to thermal 10 decomposition and reduction is preferred, for example, in-11 oryanic salts such as halide, nitrate, inorganic complex 12 compounds, or oryanic salts such as the complex salt of 13 acetylacetone, amine salt, and the like. Where, e.y., pla-14 tinum is to be deposited on the carrier, platinum chloride, 15 platinum nitrate, chloroplatinic acid, ammonium chloropla-16 tinate, potassium chioroplatinate, platinum polyamine, pla-17 tinum acetylacetonate, and the like are preferably used.
18 A promoter metal, or metal other than platinum and rhenium, 19 when employed, is added in concentration ranging from about 20 0.1 to 3 percent, preferably from about 0.05 -to about 1 per-21 cent, based on the weight of the catalyst.
22 To enhance catalyst performance in reforming opera-23 tions, it is also required to add a halogen component to the 24 catalysts, flourine and chlorine being preferred halogen com-25 ponents. The halogen is contained on the catalyst within the 26 range of 0.1 to 3 percent, preferably within the range of 27 about 1 to about 1.5 percent, based on the weight of the 28 catalyst. When using chlorine as a halogen component, it is 29 added to the catalyst within the range of about 0.2 to 2 per-30 cent, preferably within the range of about 1 to 1.5 percent, 31 based on the weight of the catalyst. The introduction of 32 halogen into catalyst can be carried out by any method at any 33 time. It can be added to the catalyst during catalyst pre-34 paration, for example, prior to, following or simultaneously 35 with the incorporation of the metal hydrogenation-dehydro-36 genation component, or components. It can also be introduced 37 by contacting a carrier material in a vapor phase or liquid ~9~
1 phase with a halogen compound such as hydrogen flouride, hy-2 drogen chloride, ammonium chloride, or the like.
3 The catalyst is dried by heating at a temperature 4 above about 80F, preferably between about 150F and 300F, 5 in the presence of nitrogen or oxygen, or both, in an air 6 stream or under vacuum. The catalyst is calcined at a tem-7 perature between about 500F to 1,200F, preferably about 8 500F to 1,000F, either in the presence of oxygen in an air 9 stream or in the presence of an inert gas such as nitrogen.
Sulfur is a highly preferred component of the cata-11 lysts, the sulfur content of the catalyst generally ranging 12 to about 0.2 percent, preferably from about 0.05 percent to 13 about 0.15 percent, based on the weight of the catalyst (dry 14 basis~. The sulfur can be added to the catalyst by conven-15 tional methods, suitably by breakthrough sulfiding of a bed 16 of the catalyst with a sulfur-containing gaseous stream, e.g., 17 hydrogen sulfide in hydrogen, performed at temperatures rang-18 ing from about 350F to about 1,050F and at pressures rang-19 ing from about 1 to about 40 atmospheres for the time neces-20 sary to achieve breakthrough, or the desired sulfur level.
21 The feed or charge stock can be a virgin naphtha, 22 cracked naphtha, a naphtha from a coal liquefaction process, 23 a Fischer-Tropsch naphtha, or the like. SUCh feeds can con-24 tain sulfur or nitrogen, or both, at fairly high levels.
25 Typical feeds are those hydrocarbons containing from about 5 26 to 12 carbon atoms, or more preferably from about 6 to 9 car~
27 bon atoms. Naphthas, or petroleum fractions boiling within 28 the range of from about 80F to about 450F, and preferably 29 from about 125F to about 375F, contain hydrocarbons of car-30 bon nu~bers within these ranges. Typical fractions thus 31 usually contain from about 15 to about 80 vol.% paraffins, 32 both normal and branched, which fall in the range of about 33 C5 to C12, from about 10 to 80 vol.% of naphthenes falling 34 within the range of from about C6 to C12.
The reforming runs are initiated by adjusting the 36 hydrogen and feed rates, and the temperature and pressure to 37 operating conditions. The run is continued at op~imum re-~8~
- 20 ~
1 forming conditions by adjustment of the major process vari-2 ables, wi.thln the ranges described below:
4 Major Operatinc3 Typical Process Preferred Process 5 Variables Conditions Conditions 6 Pressure, Psig 50-750 100-400 7 Reactor Temp., F 900-1,200 900-1,000 8 Recycle Gas Rate, SCF/B 1,000-10,000 1,500-4,000 9 Feed Rate, W/Hr/W 0.5-10 1.0-5 It is apparent that various modifications and 11 changes can be made without departinc3 from the splrit and 12 scope of the present invention, the outstanding feature of 13 which is tl~at the octane quality of various hydrocarbon feed-14 stocks, inclusive particularly of paraffinic feedstoc~s, can 15 be up~raded and improved.
1 by position, by adjusting the hydrogen and feed rates to the 2 reactors, the feed being characterized as a naphtha blend 3 which had, as shown in Table 2, the followin~ lnspections:
4 Table 2 5ASTM Distillation, F
6 Initial ~66 18 Final s.P. 358 19 Octane No., RON Clear 35.0 Gravity, API 58.9 21 Sulfur, Wt. ppm 0.5 22 ~nalysis, Vol. Percent 23 Paraffins 66.3 24 Naphthenes 22.7 Aromatics 11.0 26The temperature and pressure of the reactors in 27 each run were then adjusted to the operating conditions 28 required to produce a 100 RONC octane C5+ liquid product, and 29 the run was continued at generally optimum reforming condi-30 tions by adjustment of these and other major process vari-31 ables to those given below:
32 Major Operating VariablesProcess Conditions 33 Pressure Psig 175 34 Reactor Temp., E.I.T. F950 35 Recycle Gas Rate, SCF/B3000 36 lhe runs were continued until such time that suf-37 ficient coke had deposited on the catalyst of a reactor that - ]3 -1 regeneration, and reactivation of the catalyst of a given 2 reactor was required. Each reactor oE the series was peri-3 odically replaced in each run and the catalyst thereof re-4 generated, and reactivated for a time period as given in 5 Table 1. Reactors C and D, and Reactor S when placed in the 6 position of Reactors C and D, thus require 36 hours for re-7 generation and reactivation, whereas Reactors A and B require 8 24 hours. The regeneration in each instance was accomplished 9 by burning the co~e from the coked catalyst, initially by 10 burning at 950F by the addition of a gas which contained 11 0.6 mole percent oxygen; and thereafter the temperature was 12 maintained at 950F while the oxygen concentration in the 13 gas was increased to 6 mole percent. Reactivation in each 14 instance was conducted by the steps of: (a) redispersing 15 the agglomerated metals by contact of the catalyst with a 16 gaseous admixture containing sufficient carbon tetrachloride 17 to decompose in situ and deposit 0.1 wt.~ chloride on the 18 catalyst; (b) continuing to add a gaseous mixture containing 19 6% oxygen for a period of 2 to 4 hours while maintaining tem-20 perature of 950F; (c) purging with nitrogen to remove essen-21 tially all traces of oxygen from the reactor; and (d) reduc-22 ing the metals of the catalyst of contact with a hydrogen-23 containing gas at 850F.
24 In each instance after a regeneration/reactivation 25 sequence, the activation of the catalyst was completed by 26 sulfiding the catalyst of all of Reactors A, Bl C, D and S
27 by direct contact with a gaseous admixture of n-butyl mer-28 captan in hydrogen, sufficient to deposit 0.001-0.1 wt.%
29 sulfur on the catalyst.
Referring to Table 3 there is tabulated a conven-31 tional reactor regeneration sequence ACDS/BCDS, inclusive of 32 starting step "O" (Column 1~ wherein all of Reactors A, B, C, 33 and D are on-stream and serially aligned, with swing Reactor 34 S in standby, and eight additional steps, viz. steps 1 35 through 8, wherein Reactors A, C, D, S and B, C, D, S are 36 replaced one by one with swing Reactor S. The fourth column 37 of the table shows the time period each reactor remains off~
~ 14 -1 stream for ~e~eneration, and reactivation; a total of 264 2 hours.
3 Table 3 4 Reactors Reactor Time Required for On- Being Regeneration, and 6 Stream Regenerated Reactivation, Hours 11 4 ~ B C D S 36 16 Calculations show that in the cyclic re~orming 17 operation Reactor D is out of service for the required cata-18 lyst regeneratlon, and reactivation, 27~ of the total time 19 period. Conversely, Reactor D is in service 73% of the to-20 tal time period. Optimum benefits, however, can be achieved 21 only during the actual period when the high rhenium platinum-22 rhenium catalyst is fully utilized at the tail reactor posi-23 tion- This ideal condition, though it is not possible to 24 achieve 100~ of the time in a conventional cyclic reforming 25 operation, is represented in Table 4. Thus, ideally the use 26 of the high rhenium platinum-rhenium catalyst in the tail 27 reactor can provide a 15% activity credit and a 1.0% Cs+
28 liquid volume yield credit as contrasted with an operation 29 which employs a conventional platinum-rhenium catalyst, or 30 platinum-rhenium catalyst which contains an atomic ratio of 31 rhenium:platinum of 1:1 in all of the reactors of the unit.
32 In the normal cyc]ic reforming operation with the 33 full benefits of the high rhenium platinum-rhenium catalyst 34 utilized 73% of the period, and lost during the 27% of the 35 period when a swing Reactor S containing a platinum-rhenium 36 catalyst having an atomic ratio of rhenium:platinum of 1:1 37 i~s swung on line, the overall advantage a~ shown by reference 38 to Table 4 is reduced to a 12% activity credit and a 0.8%
39Cs+ liquid volume yield credit.
In accordance with thls new process, howevex, as further shown by reference to Table ~, an activity creclit of 14~ and a 0.9% C5~ liquid volume percent yield credit are obtained. These advantages result because the ~igh rhenium platinum-rhenium catalyst is utilized more effectively, and to a greater extent of time in the D reactor position. In both the C and D reactor positions the high rhenium-platinum-rhenium catalyst of swing Reactor S provides some advantages, even if maximum utilization is not possible. Moreover, the lower catalyst bed o swing Reactor S of the present invention takes advanta~e of the endo-therm which normally occurs in the bottom portion of a reactor in the A and B positions, this preventing yield loss by cracking such as has been observed with high rhenium platinum-rhenium catalysts employed in lead reactor positions (i.e., swing reactor charged with 100% high rhen~ium platinum-rhenium catalysts).
Table 4 950 F overall E.I.T.; 175 Psig; 3000 SCF/B
Case Credits Activity C Yield Ideal + 15~ + 1.0 LV %
Normal Cyclic Operation+ 12% + 0.8 LV %
This process + 14% + 0.9 LV %
The present new process, thus affords a much closer approach to the ideal than possible in normal cyclic reforming reactions.
In one of its aspects, optimum utilization of rhenium-promoted pla~inum catalysts is obtained by providing the catalyst of the initial, or first reactor of the series with rhenium in concentration adequa~e to provide an atomic ratio of rhenium:
platinum ranging from about 0.1:1 to about 0.5:1, preferably from about 0.3:1 to about 0.5:1. The catalyst of the intermediate re-forming zones, as represented by the reactors intermediate between the first and last reac~ors of the series, and the entry side of the swing reactor are provided with rhenium in ' f' concentration adequate to provide a weight ratio of rhenium:
platinum ranging from about 0.5:1 to about 1:1, preferably above 0,5:1 to about 0.8:1. The last reactor of the series and exit side of the swing reactor are provided with rhenium in concentra-tion adequate to provide a weight ratio of rhenium:platinum from about 1.5:1 to about 3:1, preferably from about 2:1 to about 3:1.
The last reactor of a series, whether the series contains less than three or more than three reactors, and the lower portion of the swing reactor are always provided with a catalyst which contains a weight ratio of rhenium:platinum of at least 1~:1 and preferably contains a weight ratio of rhenium:platinum ranging from about 2:1 to about 3:1.
The catalyst employed in accordance with this new process is necessarily constituted of composite particles which contain, besides a carrier or support material, a hydrogenation-dehydro-genation component, or components, a halide component and, pre-ferably, the catalyst is sulfided. The support material is constituted of a porous, refractory inorganic oxide, particularly alumina. The support can contain, e.g., one or more of alumina, bentonite, clay, diatomaceous earth, ~eolite, silica, activated carbon, magnesia, 2irconia, thoria, and the like; though the most preferred support is alumina to which, if desired, can be added a suitable amount of other refractory carrier materials such as silica, zirconia, magnesia, titania, etc., usually in a range of about 1 to 20 percent, based on the weight of the support. A
preferred support for the practice of the present invention is one having a surface area of more than 50 m2/g, preferably from about 100 to about 300 m2/g, a bulk density of about 0.3 to 1.0 g/ml, preferably about 0.4 to 0.8 g/ml, an average pore volume of about 002 to 1.1 ml/g, preferably about 0.3 to 0.8 ml/g, and an average pore diameter of about 30 to 300 A.
The metal hydrogenation-`dehydrogenation component can be composited with or otherwise intimately associated with the porous inorganic oxide support or carrier by var-1 ious techniques known to the art such as ion-exchange, co-2 precipitation with the alumina in the sol or gel form, and 3 the li~e. For example, the catalyst composi-te can be formed 4 by adding together suitable xeagents such as a salt of plat-5 lnum and ammonium hydroxide or carbonate, and a salt of alu-6 minùm such as aluminum chloride or aluminum sulfate to form 7 aluminum hydroxide. The aluminum hydroxide containing the 8 salts of platinum can then be heated, dried, formed into 9 pellets or extruded, and then calcined in nitrogen or other 10 non-agglomerating atmosphere. The metal hydrogenation com-11 ponents can also be added to the catalyst by impregnation, 12 typically via an "incipient wetness" technique which re 13 quires a minimum of solution so that the total solution is 14 absorbed, initially or after some evaporation~
It is preferred to deposit the platinum and rhen-16 ium metals, and additional metals used as promoters, if any, 17 on a previously pilled, pelleted, beaded, extruded, or 18 sieved particulate support material by the impregnation 19 method. Pursuant to the impregnation method, porous refrac-20 tory inorganic oxides in dry or solvated state are contacted, 21 either alone or admixed, or otherwise incorporated with a 22 metal or metals-containing solution, or solutions, and there-23 by impregnated by either the "incipient wetness" technique, 24 or a technique embodying absorption from a dilute or concen-25 trated solution, or solutions, with subsequent filtration 26 or evaporation to effect total uptake of the metallic com-27 ponents.
28 Platinum in absolute amount, is usually supported 29 on the carrier within the range of from about 0.01 to 3 per-30 cent, preferably from about 0.05 to 1 percent, based on the 31 weight of the catalys-t (dry basis). Rhenium, in absolute 32 amount, is also usually supported on the carrier in concen-33 tration ranging from about 0.1 to about 3 percent, prefer-34 ably from about 0.5 to about 1 percent, based on the weight 35 of the catalyst (dry basis). The absolute concentration of ; 36 each, of course, is preselected to provide the desired atomic ~ o~ w~ tt /~t~o~
'`A 37 ratio~of rhenium:platinum for a respective reactor of the 38 unit, as heretofore expressed. In the tail reactor, and e~l~s~
1 ~-~t-}~n of the swiny reactor, the rhenium is pro-2 vided in major amount relative to the platinum whereas, in 3 contrast, in all other reactors and upper portion of the 4 swing reactor the rhenium is provided in minor amount, or 5 no more than about an equal amount, relative to the plati-6 num, based on the atomi-~ weight of these metals, one with 7 respect to the other. In compositiny the metals with the 8 carrier, essentially any soluble compound can be used, but 9 a soluble compound which can easily be subjected to thermal 10 decomposition and reduction is preferred, for example, in-11 oryanic salts such as halide, nitrate, inorganic complex 12 compounds, or oryanic salts such as the complex salt of 13 acetylacetone, amine salt, and the like. Where, e.y., pla-14 tinum is to be deposited on the carrier, platinum chloride, 15 platinum nitrate, chloroplatinic acid, ammonium chloropla-16 tinate, potassium chioroplatinate, platinum polyamine, pla-17 tinum acetylacetonate, and the like are preferably used.
18 A promoter metal, or metal other than platinum and rhenium, 19 when employed, is added in concentration ranging from about 20 0.1 to 3 percent, preferably from about 0.05 -to about 1 per-21 cent, based on the weight of the catalyst.
22 To enhance catalyst performance in reforming opera-23 tions, it is also required to add a halogen component to the 24 catalysts, flourine and chlorine being preferred halogen com-25 ponents. The halogen is contained on the catalyst within the 26 range of 0.1 to 3 percent, preferably within the range of 27 about 1 to about 1.5 percent, based on the weight of the 28 catalyst. When using chlorine as a halogen component, it is 29 added to the catalyst within the range of about 0.2 to 2 per-30 cent, preferably within the range of about 1 to 1.5 percent, 31 based on the weight of the catalyst. The introduction of 32 halogen into catalyst can be carried out by any method at any 33 time. It can be added to the catalyst during catalyst pre-34 paration, for example, prior to, following or simultaneously 35 with the incorporation of the metal hydrogenation-dehydro-36 genation component, or components. It can also be introduced 37 by contacting a carrier material in a vapor phase or liquid ~9~
1 phase with a halogen compound such as hydrogen flouride, hy-2 drogen chloride, ammonium chloride, or the like.
3 The catalyst is dried by heating at a temperature 4 above about 80F, preferably between about 150F and 300F, 5 in the presence of nitrogen or oxygen, or both, in an air 6 stream or under vacuum. The catalyst is calcined at a tem-7 perature between about 500F to 1,200F, preferably about 8 500F to 1,000F, either in the presence of oxygen in an air 9 stream or in the presence of an inert gas such as nitrogen.
Sulfur is a highly preferred component of the cata-11 lysts, the sulfur content of the catalyst generally ranging 12 to about 0.2 percent, preferably from about 0.05 percent to 13 about 0.15 percent, based on the weight of the catalyst (dry 14 basis~. The sulfur can be added to the catalyst by conven-15 tional methods, suitably by breakthrough sulfiding of a bed 16 of the catalyst with a sulfur-containing gaseous stream, e.g., 17 hydrogen sulfide in hydrogen, performed at temperatures rang-18 ing from about 350F to about 1,050F and at pressures rang-19 ing from about 1 to about 40 atmospheres for the time neces-20 sary to achieve breakthrough, or the desired sulfur level.
21 The feed or charge stock can be a virgin naphtha, 22 cracked naphtha, a naphtha from a coal liquefaction process, 23 a Fischer-Tropsch naphtha, or the like. SUCh feeds can con-24 tain sulfur or nitrogen, or both, at fairly high levels.
25 Typical feeds are those hydrocarbons containing from about 5 26 to 12 carbon atoms, or more preferably from about 6 to 9 car~
27 bon atoms. Naphthas, or petroleum fractions boiling within 28 the range of from about 80F to about 450F, and preferably 29 from about 125F to about 375F, contain hydrocarbons of car-30 bon nu~bers within these ranges. Typical fractions thus 31 usually contain from about 15 to about 80 vol.% paraffins, 32 both normal and branched, which fall in the range of about 33 C5 to C12, from about 10 to 80 vol.% of naphthenes falling 34 within the range of from about C6 to C12.
The reforming runs are initiated by adjusting the 36 hydrogen and feed rates, and the temperature and pressure to 37 operating conditions. The run is continued at op~imum re-~8~
- 20 ~
1 forming conditions by adjustment of the major process vari-2 ables, wi.thln the ranges described below:
4 Major Operatinc3 Typical Process Preferred Process 5 Variables Conditions Conditions 6 Pressure, Psig 50-750 100-400 7 Reactor Temp., F 900-1,200 900-1,000 8 Recycle Gas Rate, SCF/B 1,000-10,000 1,500-4,000 9 Feed Rate, W/Hr/W 0.5-10 1.0-5 It is apparent that various modifications and 11 changes can be made without departinc3 from the splrit and 12 scope of the present invention, the outstanding feature of 13 which is tl~at the octane quality of various hydrocarbon feed-14 stocks, inclusive particularly of paraffinic feedstoc~s, can 15 be up~raded and improved.
Claims (8)
CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for reforming naphtha, with hydrogen, in a cyclic reforming unit comprised of a plurality of serially connected on-stream platinum-rhenium catalyst-containing reactors, inclusive of one or more lead reactors, a tail reactor and a swing reactor which can be substituted for any one of the on-stream reactors while the latter is off-stream for regeneration, and reactivation of the catalyst, the catalyst of the tail reactor containing a major concentration of rhenium relative to the concentration of the platinum, as contrasted with the concentrations of rhenium and platinum con-tained in the lead reactors, the weight ratio of rhenium:platinum in the tail reactor being at least about 1.5:1, while the catalyst of the lead reactors contains a weight ratio of rhenium:platinum up to about 1:1, the naphtha flowing in sequence from one reactor of the series to another and contacting the respective catalyst at reforming conditions in the presence of hydrogen, characterized by providing on the catalyst in the entry side of the swing reactor catalyst which contains a weight ratio of rhenium:platinum up to about 1:1, and providing, on the catalyst in the exit side of the swing reactor a weight ratio of rhenium:platinum of at least about 1.5:1.
2. A process according to Claim 1 further characterized in that the concentration or amount of catalyst contained in the entry side of the swing reactor which contains a relatively low concentration of rhenium, relative to the platinum, ranges from about 50 percent to about 90 percent of the total catalyst charge in the swing reactor, based on the weight of the catalyst in said reactor.
3. A process according to Claim 1 further characterized in that the concentration or amount of catalyst contained in the entry side of the swing reactor which contains a relatively low concentration of rhenium, relative to the platinum, ranges from about 50 percent to about 10 percent of the total catalyst charge, based on the weight of the catalyst in said reactor.
4. A process according to Claims 1, 2 or 3 further charac-terized in that the weight ratio of rhenium:platinum in the catalyst of the tail reactor and exit side of the swing reactor ranges from about 2:1 to about 3:1.
5. A process according to Claims 1, 2 or 3 further charac-terized in that the catalyst of the tail reactor and exit side of the swing reactor contains from about 0.01 to about 3 percent platinum and sufficient rhenium to provide the expressed weight ratio of rhenium:platinum.
6. A process according to Claims 1, 2 or 3 further charac-terized in that the catalyst of the tail reactor and exit side of the swing reactor contains from about 0.01 to about 3 percent halogen.
7. A process according to Claims 1, 2 or 3 further charac-terized in that the catalyst of the tail reactor and exit side of the swing reactor is sulfided, and contains up to about 0.2 percent sulfur.
8. A process according to Claims 1, 2 or 3 further charac-terized in that the weight ratio of rhenium:platinum in the catalyst of the lead reactors and entry side of the swing reactor ranges from about 0.01:1 to about 1:1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US27152881A | 1981-06-08 | 1981-06-08 | |
| US271,528 | 1981-06-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189814A true CA1189814A (en) | 1985-07-02 |
Family
ID=23035974
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000402892A Expired CA1189814A (en) | 1981-06-08 | 1982-05-13 | Catalytic reforming process |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0067014B1 (en) |
| JP (1) | JPS57212293A (en) |
| CA (1) | CA1189814A (en) |
| DE (1) | DE3266502D1 (en) |
| MX (1) | MX7607E (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NZ214432A (en) * | 1984-12-27 | 1988-03-30 | Mobil Oil Corp | A multi-reactor hydrocarbon catalytic conversion process. reactors cyclically operated in a continuous operation during regeneration of the catalyst |
| FR2966058B1 (en) * | 2010-10-15 | 2013-11-01 | IFP Energies Nouvelles | CATALYST OPTIMIZED FOR CATALYTIC REFORMING |
| CN107365600B (en) * | 2016-05-13 | 2020-04-21 | 神华集团有限责任公司 | Method for producing catalytic reforming raw material by hydrofining non-petrochemical naphtha and reaction device thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4174270A (en) * | 1977-11-03 | 1979-11-13 | Cosden Technology, Inc. | High severity process for the production of aromatic hydrocarbons |
| US4174271A (en) * | 1977-11-03 | 1979-11-13 | Cosden Technology, Inc. | High severity reforming |
| US4166024A (en) * | 1978-07-10 | 1979-08-28 | Exxon Research & Engineering Co. | Process for suppression of hydrogenolysis and C5+ liquid yield loss in a cyclic reforming unit |
| US4261811A (en) * | 1979-04-06 | 1981-04-14 | Standard Oil Company (Indiana) | Reforming with an improved rhenium-containing catalyst |
-
1982
- 1982-05-13 CA CA000402892A patent/CA1189814A/en not_active Expired
- 1982-05-27 EP EP19820302733 patent/EP0067014B1/en not_active Expired
- 1982-05-27 DE DE8282302733T patent/DE3266502D1/en not_active Expired
- 1982-06-08 MX MX1011682U patent/MX7607E/en unknown
- 1982-06-08 JP JP9706482A patent/JPS57212293A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0067014B1 (en) | 1985-09-25 |
| JPS57212293A (en) | 1982-12-27 |
| DE3266502D1 (en) | 1985-10-31 |
| EP0067014A1 (en) | 1982-12-15 |
| MX7607E (en) | 1990-03-15 |
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