BE553476A - - Google Patents

Description

       

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   The present invention relates to the hydroforming of hydrocarbons.



   Hydroforming is a well known process for improving boiling hydrocarbon fractions in the gasoline range.

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 or naphtha, to improve their octane numbers and their combustion or engine cleanliness characteristics. In hydroforming, the hydrocarbon is contacted at elevated temperatures and pressures and in the presence of hydrogen or a process gas, rich in hydrogen, recycled, with solid catalytic materials under such conditions. that there is a net consumption of hydrogen as well as usually a net production of hydrogen in the process.

   A series of reactions occur during hydroforming, including dehydrogenation of naphthenes to corresponding aromatics, hydrocracking of paraffins, isomerization of straight chain paraffins to form branched chain paraffins, dehydrocyclization of paraffins, and isomerization of compounds, such as ethylcyclopentane to form methylcyclohexane which is easily converted to toluene. In addition to these reactions, some hydrogenation of olefins and polyolefins occurs, and sulfur or sulfur compounds are removed by conversion to or hydrogen sulfide. catalytic metal sulphides, which makes the combustion of the hydroforming product cleaner in an internal combustion engine.



   Hydroforming is often applied to a naphtha of a fairly wide boiling range, namely, a boiling range of about 125 to about 400-430 F. It is already known that naphtha of a range lower boiling points are not significantly improved by hydroforming procedures carried out in the ordinary way. Due to the continued demand for more higher octane gasolines, it becomes increasingly important to improve these lower boiling point fractions.



   The object of the present invention is to provide an improved process for reforming or improving light naphtha and similar hydrocarbons.



   The object of the present invention is also to provide

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 This is a simple and efficient method for hydroforming light petroleum naphtha boiling in the range of about 110-250 F, preferably about 150-225 F, in contact with platinum-containing catalysts.



   It has now been found that light naphtha boiling in the range of about 110-250 F can be improved simply and effectively by hydroforming them in contact with platinum-containing catalysts at effective pressures below 125 pounds per. square inch, preferably pressures of 50 to 100 pounds.

   '
In the prior practice, two hydroforming processes using a platinum catalyst have been developed, namely (1) a continuous process, without regeneration, in which the supply of naphtha and hydrogen are. passed uninterruptedly on the catalyst under hydroforming conditions throughout the life of the catalyst, spanning a period of several months, and (2) a process with regeneration, in which the feed circulation and hydrogen is infrequently interrupted to allow regeneration of the catalyst by combustion of the coke deposits with air.

   In the process without regeneration, it is necessary to avoid hydroforming conditions which cause deactivation of the catalyst by deposits of coke or the like. For this reason, it is necessary to conduct lydroforming operations at fairly high relative pressures, greater than about 300 pounds per square inch, usually 400 to 750 pounds, and with high rates of hydrogen recycle to the reactor, usually about 4000-10,000 standard cubic feet of recycle hydrogen per naphtha feed barrel.

   Under these conditions the catalyst is relatively less active in promoting dehydrogenation reactions and relatively more active in hydrocracking than would be the case at lower pressures and recycle hydrogen levels.

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 lower, so that a lower feed rate is required for a given improvement in the octane number of the nutrient, and the hydroforming product has a higher volatility and is obtained by a slightly lower yield for a given improvement in octal number than would be the case under more favorable operating conditions.

   In addition, the maximum octane number of the hydroforming product, which is compatible with long catalyst life, is relatively low for the process without regeneration; this depends somewhat on the quality of the feed and the particular operating conditions, but this index is usually on the order of 90 (Research) for a 6 month catalyst life.

   The process without regeneration is further limited by the quality of the feedstocks which can be processed, these feedstocks should be of low sulfur content, less than about 0.01% by weight, relatively low boiling point. - lition and free of heavy bottoms, with final boiling points - below about 30 F. The prior art regeneration platinum hydroforming process has been used. developed to overcome some of the limitations of the non-regenerative process, and it is an improvement over the latter process.

   In the process with regeneration, infrequent regeneration of the catalyst is provided by combustion of the coke deposits - with. air. However, the number of regenerations during the life of the catalyst must be severely limited, because after each successive regeneration the catalyst is a little less active than after the previous regeneration.

   Likewise, each successive treatment period is shorter than the previous one; thus, for example, the first period of treatment with fresh catalyst may last for 800 hours, the second period of treatment after regeneration may last for 700 hours, the third period of treatment after 2 small last 600 hours, etc.

   In the process with regeneration, it is necessary

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 re to conduct the operation at effective pressures greater than about 200 pounds per square inch, usually 200 to 350 pounds, and at relatively high hydrogen recycle rates, usually about 4000 to 6000 standard cubic feet of hydrogen recycled by 'naphtha feed barrel. Under these slightly more favorable conditions, the dehydrogenation activity of the catalyst is higher and the hydrocracking activity of the catalyst is lower so that, for a product of given octane number, a level of d A little more feed can be used, and a little more yield is obtained of the product having a lower volatility.

   The octane number of the product from the regeneration process is also higher; we have about 96 Research octane product for 6 month catalyst life. The regeneration process is also somewhat less demanding with respect to the quality of the feedstock. Naphtha containing up to about 0.03% sulfur can be processed without prior desulfurization.



     The object of the present invention is to provide an operation for the hydroforming of naphtha in the presence of an air-regenerable platinum catalyst and to provide improved means for regenerating the platinum catalyst which is deactivated during the treatment phase. .



   The present invention, in a preferred variation, comprises hydroforming naphtha in the presence of a catalyst bed containing a platinum group metal, preferably platinum itself. In this preferred operation, the pressure is kept relatively low and the rates of so-called recycle gases are relatively low. In other words, while in the usual hydroforming operation using platinum the effective pressures in the reaction zone are maintained in the range of 200 to 750 pounds per square foot, the present invention has in particular. seen an operation at effective pressures of the order

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 from 0 to 200 pounds per square inch.

   And, while in prior practice the recycle gas rates are in the range of 4000 to 7500 cubic feet of hydrogen, the present invention is directed to the use of about 100 to 2000 feet. Recycling hydrogen gas cubes to hydroforming area by fueled oil barrel.



  It is also an important feature of the present invention to provide a reactivation means for restoring the activity of the catalyst which is deactivated during its use in the hydroforming phase, and this involves treating the catalyst with. air mixed with chlorine.



   The present invention relates, therefore, in a general manner, to a method of carrying out a hydroforming process using a catalyst containing platinum under relatively low pressure conditions, namely near- effective sions of the order of 50 pounds per square inch, and very low recycle gas rates, i.e., one feed, to the reaction zone, with each barrel of oil, less 1000 standard cubic feet of recycle gas, preferably 150 to 500 standard cubic feet of hydrogen per barrel of oil.



   Under these conditions, maximum yields of high octane product are possible and the installation costs are considerably reduced due to the significant reduction in the recycle gas rate.



   When operating under these conditions, three problems must be solved: (1) a unique method of providing heat of reaction must be provided; this results from the very limited quantity of recycle gas, which must be used; (2) a unique type of fluidized reactor must be employed due to the very high activity of the freshly regenerated catalyst which renders a dense fluidized bed too shallow current for good reaction efficiency;

   and (3) a unique method of continuously reactivating the spent catalyst must be provided to maintain its high activity.

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 developed under conditions which cause rapid deposition of carbon.



   The low pressure platinum hydroforming process is especially suitable for improving the octane number of virgin naphtha boiling in the range of about 150 to 200 F.



  The Ce fraction boiling below about 150 F is not improved by the process to as great an extent as the C6 and: 7 hydrocarbons; therefore, the C5 fraction is not an especially advantageous component of the process. 'food. On the other hand, the presence of C5 hydrocarbons in the feed is not particularly harmful so that it may be preferable to include this fraction in the feed if, in doing so, a additional distillation phase in the preparation of the feed. The fraction boiling above 200 F up to about 225 or 250 F lends itself fairly well to current hydroforming processes using,

   molybdenum oxide or platinum as a catalyst at an effective pressure of about 200 pounds per square inch or more, and such a fraction may be included in the ali. mention to such processes, if desired. On the other hand, this fraction also lends itself well to the present low pressure platinum process, so the method of treating this particular fraction of the virgin naphtha feed will depend on circumstances such as the availability of the naphtha installation and volumes ... fractions of different boiling ranges desired to be treated ... It has been found that, in the effective pressure range of 50 to 1.00 pounds per square inch,

   it is possible with catalysts containing platinum to improve a light virgin naphtha having an average boiling point of 169 F and a Research Clear octane number of 66, to a hydrofring product having an index of. Research Clear octane of about 90 and above, in yields of about 75% by volume, and a hydroforming product having a Research Clear octane number of about 95 or above in yields of about 68% by volume. However, hydroforning this naphtha at an 'effective' pressure of 200 pounds per square inch with

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 a molybdenum oxide catalyst gives a hydroforming product having only about an octane number of about 85 in yields of about 75% by volume or about 85 in yields of about.
68% by volume.

   Again, hydroforming this naphtha at an effective pressure of 200 pounds per square inch with catalysts containing platinum gives a hydroforming product having only an octane number of 85 with a yield of 75. % by volume.



   In addition, it has been found impossible to increase the octane number much above about 87 by hydroforming with the platinum catalyst at an effective pressure of 200 pounds per square inch.



   In other words, the hydroforming process with a platinum catalyst at an effective pressure of 200 pounds per square inch has an octane cap that is only slightly higher than
87, when applied to light virgin naphtha, while the cap of the octane number for the lower pressure platinum process is well above 95, when this process is applied to the same feed of light virgin naphtha.

   Under these reaction conditions, there is a tendency for carbon to form very rapidly on the catalyst and, therefore, it becomes necessary to regenerate the catalyst very frequently. Therefore, the process is most advantageously carried out in a fluidized solids system, so that the catalyst can be properly circulated from the reaction zone to the regeneration zone where the deposits. carbonaceous substances can be removed by combustion. It is also advantageous to provide means for subjecting part of the regenerated catalyst, also preferably continuously, to reactivation with a halogen or a halogen compound, such as chlorine or hydrochloric acid.

   Free halogen, such as chlorine, is the preferred treating agent for reactivation. In addition to the accumulation of. poisons, the deactivation of platinum hydroforming catalysts occurs by two mechanisms, namely (1) loss of chlorine or other halogen which is normally present as part of the compound

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 catalyst and which contributes substantially to catalytic activity, and (2) agglomeration of platinum metal into relatively large or massive crystals having crystal diameters in excess of about 50 Angstroms. Treatment of the catalyst with a halogen compound, such as hydrochloric acid or the like,

   is effective in restoring the halogen content of the catalyst to the desired value and at this stage the treatment is effective in restoring the activity of deactivated or partially deactivated catalysts. However, treatment with a halogen compound, such as hydrochloric acid or the like, is not effective for reducing the size of platinum crystals; therefore, such treatment is only partially effective in restoring the catalytic activity of deactivated catalysts.

   On the other hand, the treatment of the catalyst with an elemental halogen, such as chlorine or the like, not only restores the halogen content of the catalyst to the desired degree but also accomplishes the redispersion of the platinum metal by breaking the large crystallites of the catalyst. platinum.



  This treatment is, therefore, quite effective in restoring the activity of deactivated catalysts whose loss of activity was not due to the accumulation of poisons, such as arsenic or the like.



   In the practice of the present invention, the increased rate of catalyst deactivation requires that the catalyst be regenerated more often. In other words, only short treatment periods of about 1 to 24 hours can be tolerated while still maintaining a high yield to octane ratio and high catalyst activity.



   In the accompanying drawings are shown an apparatus and an alternative embodiment of the present invention.



   Referring in detail to Figure 1, the reference
1 represents a hydroforming reactor which presents expansions

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 upper and lower. Reference numeral 2 denotes a catalyst regenerator, and numeral 3 denotes a shot heater, which is used to supply heat to the endothermic reaction occurring in reactor 1. In operation, a mixture of gases of Recycle and naphtha is charged from line 4 to furnace 5 where it is heated to a temperature of about 925 to 975 ° F, and then charged through line 6 to reactor 1.

   It should be noted that the mixture in line 4 can be subjected to heat exchange with hot product coming from reactor 1 before being charged to oven 5, and this in means not shown. It will be noted that the reactor 1 contains a bed of catalyst C which is in fluidized form and has a higher dense phase level L. The reactor 1 is provided with a draw-off tube 8 so that the catalyst circulation takes place from the bed. C towards and in the bottom of tube 8, then upwards mixed with the naphtha vapors and the recycle gas. It is in this draw-off tube that the reaction takes place.

   The use of this draw-off tube allows efficient use of the high activity catalyst. The upper part of the draw-off tube is for., Seen by fins 9 which allow separation of the catalyst from the gas-like material, this catalyst then descending. to bed C. The expansion 10 of reactor 1 also operates to effect a significant separation of the catalyst from the gas-like material.



  This gas-like material then passes to the top of the reactor 1, and before being removed from the reactor, it is forcefully sent through one or more cyclones S in which the catalyst still entrained in the gas-shaped material is removed and returned to the catalyst bed C, via one or more plunging pipes d. The crude product mixed with hydrogen is removed at the top of reactor 1 through line 11 and passes from there through a condenser 12 in which it is cooled to a temperature of about 100 F, then it passes through the line 13 to a separator'14.

   The product

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 The crude is removed therefrom and supplied to a common finishing still 14a. At the top of the separator 14, a gas-like material which contains 85% to
95% hydrogen, the remainder being light hydrocarbons. Because of its high hydrogen content, this material is of particular interest in other processes, such as in the hydroforming of naphtha and / or sulfur-bearing feeds. This hydrogen-rich gas can be removed from the present system for the above uses through line 16. A small portion of this material is recycled through line 15 to line 4 for reuse. in the process.



   As under the severe conditions under which the present process operates, catalyst C is quickly contaminated with carbonaceous and other deposits, such deposits causing catalyst deactivation, it is necessary to regenerate the catalyst at frequent intervals. To this end, the catalyst is removed from the reactor 1 through line 35 to a stripping or scrubbing apparatus 36 where it is scrubbed with steam to remove occluded hydrocarbons and / or adsorbed and hydrogen. The catalyst is removed from apparatus 36 and is transported in air through line 22 to the regenerator
2, the air being limited in quantity to that which will cause the temperature of the catalyst to exceed 1050 F.

   The catalyst is carried in suspension in this air stream in the regenerator 2 and is treated there in the form of a fluidized bed C1 under conditions more fully explained below. Bed C1 has an upper level of dense phase L1 above which there is a suspension of solids in dilute phase in a gas-like material. Before the fumes are removed from the regenerator, they are passed through one or more gas and solids separators, to remove entrained catalyst which is returned to bed C1 through one or more dip pipes d. The fumes are removed at the top

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 of regenerated Them.

   The regenerated catalyst, as well as the pellets coming from the reactor and which serve to regulate the temperature of the regenerator, then circulate to a lower part 31 of smaller cross section than that of the main part of the regenerator. In this part 31, the practical slow carbon catalyst is treated with air for an extended period of time. This treatment serves to renovate the catalyst, preferably by reducing the crystal size of the platinum particles. To this end, the flow of air through the inlet line 32, upwardly through the catalyst in the baffle section 31, is continued for an extended period of time to reactivate the catalyst.

   As the catalyst preferably contains a few weight percent chlorine, and since this chlorine may be lost during the reaction process and / or the regeneration process, supplemented chlorine may be added by line 33 to the catalyst in section 31. The regenerated and reactivated catalyst is returned to reactor 1 through line 34.



   As mentioned previously, shot is used to provide most of the heat of reaction.



  To this end, hot shot coming from the burner vessel 3 penetrates the lower expansion 18 of the reactor 1. In this zone, these shots release their heat and are deposited in the separation device 37. In this zone 37, the catalyst is separated from the shot with a recycle gas supplied by line 20. The pure shot then passes to a lower separation zone 38 where hydrogen and occluded hydrocarbons and / or adsorbs are separated from the shot with steam entering through pipe 21. The shot then descends into vertical pipe 24 and is divided into two streams.



  A stream, as mentioned above, is carried with air (entering through 30a) through line 30 to the regenerator.

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 where it comes out at temperature setting. Most of the shot is transported through line 25 to the elevated burner vessel 3. The transport gas formed by combustion of a fuel supplied to the burner through line 26. The burner vessel is at such a height that with the reactor at an effective pressure of 50 pounds per square pumice, the burner is at substantially atmospheric pressure. The differential pressure is supplied by the vertical shot pipe 39.

   With this arrangement, air substantially at atmospheric pressure can be supplied to the burner vessel through line 40, thereby allowing savings in air compression. Air is charged to the shot burner 3 through line 40 and burns the fuel supplied through lines 25 and 26 with release of heat which is taken up by the shot. The shots are formed into a dense fluidized bed C2 in the burner 3 by adjusting the superficial gas velocity, the bed having an upper level of dense phase L2, above which there is a dilute phase extending from level L2 up to and from the container.

   Before the combustion gases are removed from the burner 3, they are sent to one or more separators S of solids and gas, in which entrained solids are separated and returned to bed C2 through one or more plunging pipes d . The gases emerge from the burner 3 through line 29, and their sensitive and chemical heat can be recovered to preheat the feed oil in order to generate steam, to drive the turbine of the air compressor, or to be used in another way. The heated shot is removed through a baffle fitting 27, where it is treated with steam or other gas entering through line 27 or for the purpose of removing occluded or adsorbed oxygen.

   The heated shots are returned to the reactor 1 via the transfer line or vertical line 39.



    @
In the prior practice in which the technique

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 of the fluidized catalyst has been employed with a hydroforming catalyst, or in which a fixed bed of catalyst has been employed in hydroforming, more than 50% of the heat required to support the endothermic hydroforming reaction has been provided by recycle gas. This recycle gas has a relatively low heat capacity, which requires 4000 to 8000 standard cubic feet per barrel to provide the necessary heat. The circulation of this large quantity of gas is carried out only at great expense.



   In the present process, a certain amount of heat is obviously obtained as the heat content of the hot regenerated catalyst returned from regenerator 2 to reactor 1.



  Some heat is supplied by the combined stream of feed and recycle gas entering the reactor.



  However; the total heat thus recovered is a small fraction of that required in reactor 1. To supply most of the heat to the reaction zone according to the present invention, an inert material, such as mullite, under particle form having a size of 400 to 500 microns, for example, and commonly referred to as shot, is heated in the burner 3 and, from there, it is charged into the reaction zone 1. The shot is heated by combustion of the fuel which. can be tail gas obtained from the product recovery system or any liquid fuel, such as kerosene, etc.



   In order to explain the invention, the following example is given.



  Example 1
A naphtha having the following inspection was processed according to the present invention under the following conditions with the following results.

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  Power inspection
 EMI15.1
 
<tb> Gaume <SEP> of boiling, <SEP> F <SEP> 215 <SEP> to <SEP> 335 <SEP> '
<tb>
<tb>% <SEP> vol. <SEP> of aromatics <SEP> 10
<tb>
<tb>% <SEP> vol. <SEP> of <SEP> paraffins <SEP> 51
<tb>
<tb>% <SEP> vol. <SEP> of <SEP> naphthenes <SEP> 39
<tb>
<tb> Octane <SEP> number <SEP> CFRR <SEP> 51
<tb>
 Conditions in the reactor 1.
 EMI15.2
 
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  Condition <SEP> Range <SEP> of
<tb>
<tb> preferred <SEP> conditions
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<tb>
<tb>
<tb> 0.5% <SEP> in <SEP> weight <SEP> of <SEP> Pt <SEP> on <SEP> 99.5%
<tb>
<tb>
<tb>
<tb> '<SEP> Catalyst <SEP> in <SEP> weight <SEP> of beta-alumina, <SEP> more
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<tb>
<tb>
<tb> Catalyst <SEP> 2% <SEP> Cl2 <SEP> by <SEP> ratio <SEP> to <SEP> weight
<tb>
<tb>
<tb>
<tb> total <SEP> of <SEP> catalyst
<tb>
<tb>
<tb>
<tb> Duration <SEP> of <SEP> the <SEP> period <SEP> of <SEP> trai- <SEP> total <SEP> ca-Galyseur
<tb>
<tb>
<tb> element <SEP> of the <SEP> catalyst <SEP> 8 <SEP> 1-12
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Temperature ,.

   <SEP> F <SEP> 900 <SEP> 675-975
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Effective <SEP> pressure, <SEP> pounds <SEP> by
<tb>
<tb>
<tb> inch <SEP> square <SEP> 50 <SEP> 0-100
<tb>
<tb>
<tb>
<tb>
<tb> Oil supply <SEP> rate <SEP>, <SEP> li-
<tb>
<tb>
<tb>
<tb> vres <SEP> of oil <SEP> supplied <SEP> by <SEP> hour
<tb>
<tb>
<tb> by book <SEP> of <SEP> catalyst <SEP> in <SEP> on
<tb>
<tb>
<tb> reactor <SEP> 9 <SEP> 6-14
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Standard <SEP> cubic <SEP> <SEP> feet of hydrogen,
<tb>
<tb>
<tb> powered <SEP> to <SEP> the <SEP> zone <SEP> of <SEP> reaction,

  
<tb>
<tb>
<tb> per <SEP> barrel <SEP> of oil <SEP> 200 <SEP> 200-1000
<tb>
<tb>
<tb>
<tb>
<tb> Concentration <SEP> of hydrogen <SEP> in <SEP> on
<tb>
<tb>
<tb> gas <SEP> hydrogenated <SEP> recycled <SEP> 90 <SEP> 85-95
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> <SEP> speeds in <SEP> the <SEP> reactor, <SEP> foot / -
<tb>
<tb>
<tb> second.
<tb>
<tb>
<tb>



  Zone <SEP> of <SEP> reaction <SEP> in <SEP> the <SEP> 'tube <SEP> of
<tb>
<tb>
<tb> racking <SEP> 10 <SEP> 5-15
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Zone <SEP> of <SEP> heating <SEP> lower <SEP> 0.25 <SEP> 0.2-0.5
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Dimensions <SEP> of <SEP> particles <SEP> of <SEP> ca-
<tb>
<tb>
<tb> analyzer, <SEP> microns
<tb>
<tb>
<tb> 0-44 <SEP> '<SEP> 5 <SEP> 0-20
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<tb>
<tb>
<tb>
<tb>
<tb> 44-74 <SEP> 43 <SEP> 3 <SEP> 0-5 <SEP> 0 <SEP>
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<tb>
<tb>
<tb>
<tb> 74-104 <SEP> 47 <SEP> 35-55
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 104 <SEP> and <SEP> plus <SEP> 5 <SEP> 0-10
<tb>
 

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 Product inspection
 EMI16.1
 
<tb>% <SEP> vol. <SEP> of hydrocarbons <SEP> C <SEP> and <SEP> plus,
<tb>
<tb>
<tb> by <SEP> report <SEP> to <SEP> 1 '<SEP> power supply <SEP> 89
<tb>
<tb>
<tb>
<tb>% <SEP> vol.

   <SEP> aromatics <SEP> in <SEP> C5 <SEP> and <SEP> plus <SEP> 55
<tb>
<tb>
<tb>
<tb>
<tb> vol. <SEP> Naphthenes <SEP> in <SEP> C5 <SEP> and <SEP> plus <SEP> 2
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> vo. <SEP> paraffins <SEP> in <SEP> C5 <SEP> and <SEP> plus <SEP> 43
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> vol. <SEP> of <SEP> C4 <SEP> 2.6
<tb>
<tb>
<tb>
<tb> Gas <SEP> sec <SEP> 4.3
<tb>
<tb>
<tb>
<tb>
<tb> <SEP> octane number <SEP> 90
<tb>
 
In the previous example, in order to maintain the activity of the catalyst, it was found that it was necessary to regenerate every eight hours:

   This was done under the following conditions:
Conditions in the regenerator
 EMI16.2
 
<tb> Condition <SEP> Range <SEP> of
<tb> preferred <SEP> conditions
<tb>
<tb> Temperature, <SEP> F <SEP> 1100 <SEP> 1000-1125
<tb>
<tb> Effective <SEP> pressure, <SEP> pounds <SEP> by
<tb> inch <SEP> square <SEP> 50 <SEP> 0-100
<tb>
<tb> Duration <SEP> of <SEP> stay <SEP> of <SEP> catalyst
<tb> in <SEP> the <SEP> regenerator, <SEP> minutes <SEP> 15 <SEP> 5-30
<tb>
<tb> Oxygen <SEP> in <SEP> the <SEP> gases <SEP> of <SEP> combustion, <SEP> weight <SEP> 5 <SEP> 2-10
<tb>
 
After most of the carbonaceous and other deposits were removed, air was used to remove the remaining catalyst deposits.

   It was found, however, that this method did not completely restore the activity of the catalyst and, therefore, the catalyst was subjected to the following additional treatment, in the baffled portion 31 of the regenerator 2.



   Additional treatment of free carbon free catalyst
 EMI16.3
 
<tb> Condition <SEP> Range.de
<tb>
<tb> preferred <SEP> conditions
<tb>
<tb>
<tb>
<tb>
<tb> Temperature, <SEP> F <SEP> 1075 <SEP> 950-1100
<tb>
<tb>
<tb>
<tb>
<tb> Effective <SEP> pressure, <SEP> pounds <SEP> by
<tb>
<tb>
<tb> inch <SEP> square <SEP> 50 <SEP> 0-100
<tb>
<tb>
<tb>
<tb> Composition <SEP> of <SEP> gas <SEP> 'of <SEP> treatment <SEP> 1% <SEP> Cl2 <SEP> + <SEP> 99% <SEP> air <SEP> (sec)
<tb>
<tb>
<tb>
<tb> Duration <SEP> of <SEP> treatment, <SEP> hours <SEP> 1 <SEP> 1 / 2-4
<tb>
 

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After the treatment with the dilute gas, as mentioned above, the catalyst was treated with air for a period of 5 minutes to an hour to remove excess chlorine.



   The relatively low pressure, low recycle gas rate process according to the present variant of the invention, and using a fluidized bed of a platinum catalyst, is one process. practicable provided that the foregoing technique of reactivating the deactivated catalyst is employed in conjunction with the treatment process. Due to the rapid deactivation of the catalyst under the stringent conditions of the present process, the catalyst must be regenerated and treated with chlorine at frequent intervals, so that the length of time the catalyst stays in the zone. reaction time is 1 to 12 hours, after which said catalyst must be removed and reactivated. The fact that low pressures and low recycle gas rates are used achieves significant operating savings.

   For example, the recycle gas compressor at the reactor and the associated heat exchange installation are of very much reduced dimensions.



   The present process can be carried out at standard hydroforming temperatures, but the pressure, and the recycle gas rate, can be much lower. For example, the pressure can vary within the limits of 0 to 100 pounds per square inch, and the rate of recycle gas from 200 to 1000 standard cubic feet of hydrogen supplied to the reaction zone per barrel of feed. of oil. The catalyst may contain from 0.5 to 1.5% by weight of platinum supported on an active form of alumina. A small percentage of silica can be included in the composition of the catalyst, and it is also advantageous to have a small percentage of chlorine associated with the composition of the catalyst.

   Palladium can be used instead of platinum, but the amount of palladium should be at least three times that of platinum because palladium is not as active.

 <Desc / Clms Page number 18>

 



   Another variant of the present invention is illustrated in FIG. 2. This relates to the heat treatment of the regenerated catalyst with a view to reactivating the latter. Referring to Figure 2, numeral 110 denotes a reactor vessel containing a fluidized bed 112 of catalyst consisting of a catalyst containing 0.01 to 1% by weight of platinum or other metal.



   A preferred catalyst is about 0.1 to 0.6% by weight of platinum widely dispersed on a high surface area alumina support of about 150 to 220 square meters per gram. The pressure in the container. 110 can be on the order of 0 to 200 pounds per square inch, and is preferably about 50 pounds. The temperature of the catalyst bed can be on the order of about 800 to 975 F; however, under the conditions of low pressure and low levels of recycle hydrogen of the present invention, the dehydrogenation activity of the platinum metal catalysts is extremely high, so that the reaction temperature can be low. slightly lower than that of the hydroforming processes of the prior art.

   A preferred temperature is on the order of 875-910 F. A feed of naphtha, which does not specifically require fractionation or other prior purification, is preheated in heater 114 and sent through line 116 to the lower section of the tank. reactor 110. The present process is not particularly demanding with respect to the quality of the naphtha feed; this feed can have a final boiling point as high as about 400 F and can contain relatively large amounts of sulfur, up to about 0.2% by weight. The naphtha feed is preheated in the heater. 114 to a temperature on the order of 900-1050 F, preferably about 975-1000 F.

   Recycle hydrogen, which has been preheated to 900 to 1300 F, preferably about 1200 F, in a heater 118 and which carries freshly regenerated and reactivated catalyst, coming from lines 152 and 157,

 <Desc / Clms Page number 19>

 is also introduced into the lower section of the reactor 110 through line 120.

   Or, instead of preheating separately from the naphtha feed and recycle hydrogen, the naphtha feed from line 117 can be mixed with the recycle gas from line 132, and the combined stream can be preheated in the heater 118; in this case, the preferred preheating temperature is on the order of 900 to 1000 F. The recycle gas normally contains 65 to 90 moles;:. hydrogen, the remainder being light hydrocarbon gases. The amount of recycle gas employed may be on the order of about 50 to 2000, preferably about 100 to 1000 standard cubic feet per barrel of naphtha feed. However, if desired, recycle gas can be omitted altogether.

   In addition to preheating the feed and recycle gas, the additional mass of heat required by the endothermic hydroforming reaction can be supplied to catalyst bed 112 by heating coil 115 submerged therein. Hot flue gases or the like can be passed through this coil 115. The naphtha vapor and recycle gas rise through the catalyst bed 112, whereupon the naphtha undergoes hydroforming. After leaving the catalyst bed 112, the hydroforming vapor and gas pass through a standard catalyst recovery facility, such as a cyclone separator or filter, and exit through line 122 and a condenser. or refrigerator 124 to a liquid and gas separator 126.

   The produced naphtha is removed from the system through line 128, excess product gas is removed from the system through line 130, and the remainder of the gas is recycled through line 132. When feeding high sulfur naphtha , greater than about 0.02 '; - ;. by weight, it is preferable to remove the hydrogen sulphide from the recycle gas of the line 132, by means of a washing apparatus with caustic material or other common washing means. The bed catalyst

 <Desc / Clms Page number 20>

 112 passes into the vertical pipe 134 where it is separated from the adsorbed hydrocarbons by the hydrogen coming from the pipe 136.



  This uncluttered insi catalyst passes into line 138 where it is carried by a stream of air and transported to regenerator 140.



  This, which is a relatively small vessel because of the low rate of coke formation on the platinum and palladium catalysts, is maintained at a temperature of 900 to 1200 F, preferably 1000 to 1100 F. The pressure in this regenerator 140 is approximately the same as that prevailing in the reactor 110. In this vessel 140, the coke deposits of the catalyst are removed by combustion by virtue of the gas introduced through the line 138. During the combustion. combustion of coke, a certain quantity of water is formed by combustion of the hydrogen in the coke.

   This water is separated from the catalyst and removed at the top with the flue gases passing through usual means of catalyst recovery, such as a cyclone separator or filter, etc., to easily exit the system via the outlet. line 142. As with the subsequent reactivation with chlorine, it is desirable to have a fully regenerated or coke-free catalyst, it is preferable to use excess air in regenerator 140; The oxygen content of the flue gases in line 142 should be greater than 2 / -, preferably even greater than 5%. The regenerated catalyst passes through line 144 into the upper section of the chlorine reactivation vessel 146.

   Since it is desirable to maintain substantially anhydrous conditions in the reactivation vessel 146, water vapor is further separated from the catalyst passing through line 144 by air introduced through line 148. Reactivation vessel 146 which may be of small cross section relative to its height is preferably maintained at the same pressure and temperature as the regenerator 140.

   Chlorine gas or a mixture of chlorine gas and is introduced into the vessel 146 in the vicinity of the center of

 <Desc / Clms Page number 21>

 this, through a line 150, and air is introduced into this container 146 near the bottom thereof, through line 154. The air and chlorine rise through the container 146 and are removed from the container. system via line 145, while the catalyst from line 144 descends through this container 146. In this way, the. Upper section of the reactivation vessel includes a chlorine treatment zone, in which catalyst.

   regenerated product is contacted with a mixture of gaseous chlorine and air, and the lower section of the reactivation vessel 146 includes a separation zone in which adhered chlorine is separated from the treated catalyst by means of air. In the upper chlorine treatment zone of vessel 146, the partial chlorine pressure may be on the order of about 0.001 to 2 atmospheres, preferably about 0.01 to 1 atmosphere. The quantity of chlorine admitted to container 146 through line 150 may be of the order of 0.1 to 2% by weight, preferably about 0.5% by weight, of the catalyst introduced into container 146 through line 144.

   As mentioned above, the temperature and the total pressure (air + chlorine) in the chlorine treatment zone are preferably the same as those prevailing in the regenerator vessel 140. The residence time of the catalyst in the treatment by chlorine can be of the order of 15 seconds to 1 hour, preferably about 1 to 15 minutes. The action of the chlorine treatment on the catalyst is to destroy platinum crystals and redisperse the metal on the surface of the catalyst, thereby fully restoring the activity of the catalyst to that of the catalyst. a fresh catalyst.

   As the chlorine-treated catalyst moves down from the upper chlorine treatment zone of vessel 146, into the lower separation zone of that vessel, adherent chlorine is separated from the catalyst by air from the vessel. line 154. However, it is usually preferable not to completely separate the chlorine from the catalyst.

 <Desc / Clms Page number 22>

 The bottom, and the bottom of the separation zone, as well as that of the chlorine treatment zone, provide an important means for controlling the hydrocracking activity of the catalyst and, therefore, for controlling the volatility. naphtha produced which has undergone hydroforming, to the desired degree.

   Regardless of the temperature and pressure in vessel 146 which are generally set by those of vessel 140, the amount of chlorine remaining on the separated catalyst can be controlled by the amount of air introduced into the separation zone. separation through line 154 and the partial pressure of chlorine, employed in the chlorine catalyst treatment zone.

   The quantity of chlorine remaining on the - which has undergone the separation is all the lower and the hydro- cracking activity of the catalyst is all the higher, and therefore the volatility of the naphtha produced is also d the higher the lower the quantity of separation air employed and the higher the chlorine partial pressure in the treatment zone.



  In general, the total amount of chlorine (i.e., both chemically combined chlorine and adsorbed chlorine) remaining on the catalyst. which has undergone the separation operation may be of the order of about 0.2 to 1.25% by weight, preferably about 0.5 to 1% by weight.

   The reactivated and separated catalyst passes from vessel 146 through line 152 into line 120 where it is carried by recycle gas or a mixture of recycle gas and naphtha feed and transported to the vessel. reactor 110, as previously reported. If desired, everything. the catalyst leaving the regenerator vessel 140 can be reactivated by treatment with chlorine in the vessel II; -6 before its reintroduction into the reactor vessel 110 as described above;

   however, it is generally preferable to reactivate only a portion, for example one-tenth to one-half of the catalyst from regenerator 140, in which case the remainder of the catalyst flows directly from regenerator 140 through lines 157 and 120 to vessel.

 <Desc / Clms Page number 23>

 reactor 110.



   In order to better understand the present invention, the following example II is given.



  Example II - A canker sore having the following inspection was subjected to the hydroforming according to the present invention.



   Power inspection.
 EMI23.1
 
<tb>



  Severity <SEP> 54.5 <SEP> API
<tb>
<tb> Range <SEP> of boiling <SEP> 200-33 <SEP> 0 F <SEP>
<tb>
<tb> Naphthenes, <SEP>% <SEP> in <SEP> 'weight <SEP> 41
<tb>
<tb> Paraffins, <SEP>% <SEP> in <SEP> weight¯ <SEP> 43
<tb>
 
 EMI23.2
 Aromatics, fi by weight 16
 EMI23.3
 
<tb>% <SEP> in <SEP> weight <SEP> of <SEP> sulfur <SEP> 0.004
<tb>
<tb> Octane <SEP> number <SEP> CFRR <SEP> 57.5
<tb>
 
 EMI23.4
 Conditions in the hydroforming area
 EMI23.5
 
<tb> Composition <SEP> of the <SEP> catalyst <SEP> 0,

  6% <SEP> of <SEP> platinum <SEP> on <SEP> alumina
<tb>
<tb>
<tb> Temperature <SEP> 900 F
<tb>
<tb>
<tb>
<tb> Effective <SEP> pressure <SEP> 50 <SEP> pounds <SEP> per <SEP> inch <SEP> square
<tb>
<tb>
<tb> Weight / hour / weight <SEP> 4
<tb>
<tb>
<tb>
<tb> Cubic feet <SEP> <SEP> of <SEP> gas <SEP> of <SEP> recycling <SEP> con-
<tb>
<tb> holding <SEP> from <SEP> hydrogen <SEP> to <SEP> the <SEP> zone <SEP> of hy-
<tb>
<tb> droforming <SEP> by <SEP> barrel <SEP> of oil <SEP> fed
<tb>
<tb> to <SEP> the <SEP> hydroforming <SEP> zone <SEP> 200
<tb>
<tb>
<tb> Concentration <SEP> of hydrogen <SEP> in <SEP> on
<tb>
<tb> gas <SEP> from <SEP> recycling <SEP> approximately <SEP> 80%
<tb>
<tb>
<tb>
<tb> Duration <SEP> of <SEP> the <SEP> phase <SEP> of hydroforming
<tb>
<tb> by <SEP> cycle, <SEP> in <SEP> hour,

   <SEP> 1
<tb>
 Conditions in the regenerator
 EMI23.6
 
<tb> Temperature <SEP> 1050 F
<tb>
<tb>
<tb> Effective <SEP> pressure <SEP> 50 'pounds <SEP> per <SEP> inch <SEP> square
<tb>
<tb>
<tb> Duration <SEP> of <SEP> stay <SEP> 10 <SEP> minutes
<tb>
<tb>
<tb>
<tb> in <SEP> weight <SEP> of'carbon <SEP> on <SEP> on
<tb>
<tb> catalyst <SEP> regenerated <SEP> less <SEP> of <SEP> 0.1%
<tb>
<tb>
<tb>
<tb> in <SEP> weight <SEP> of <SEP> sulfur <SEP> on <SEP> the <SEP> cata-
<tb>
<tb> lyser <SEP> regenerated <SEP> less <SEP> of <SEP> 0.1%.
<tb>
 

 <Desc / Clms Page number 24>

 



  Conditions in the chlorine treatment device
 EMI24.1
 
<tb> Temperature <SEP> 1050 F
<tb>
<tb>
<tb>
<tb>
<tb> Effective <SEP> pressure <SEP> 50 <SEP> pounds <SEP> per <SEP> inch <SEP> square
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Duration <SEP> of <SEP> stay <SEP> 5 <SEP> minutes
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Composition <SEP> of gas <SEP> of <SEP> treatment <SEP> 4% <SEP> of <SEP> chlorine <SEP> in <SEP> of <SEP> air
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Partial <SEP> pressure <SEP> of <SEP> chlorine <SEP> 0,

  175 <SEP> atmosphere
<tb>
<tb>
<tb>
<tb>
<tb> Duration <SEP> of <SEP> treatment <SEP> to <SEP> air <SEP> followed
<tb>
<tb>
<tb> from <SEP> treatment <SEP> to <SEP> chlorine <SEP> 5 <SEP> minutes
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> in <SEP> weight <SEP> of <SEP> chlorine <SEP> on <SEP> the <SEP> cataly-
<tb>
<tb>
<tb> sor <SEP> having <SEP> undergone.the <SEP> separation <SEP> approximately <SEP> 0.7
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Inspection <SEP> of the <SEP> product
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Severity <SEP> 43.7 <SEP> API
<tb>
<tb>
<tb>
<tb>
<tb> Range <SEP> of boiling <SEP> C5 <SEP> to <SEP> 350 F
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> Octane <SEP> number <SEP> CFRR <SEP> 96
<tb>
 
The temperature in the hydroforming zone can vary from 800 to 975 F, the pressure can vary from 0 to 200 pounds per square inch,

   and the duration of each productive phase of the complete treatment cycle, including regeneration and chlorine treatment, may vary from 1 to 20 hours. The composition of the catalyst may vary from a catalyst containing 0.01 wt% platinum to a catalyst containing 1 wt% platinum, the remainder being a suitable carrier.

   Further, palladium can be used instead of platinum as the active hydrogenation and dehydrogenation component of the catalyst, but palladium must be used in about three times the amount of platinum to obtain similar results. With regard to the treatment of the regenerated catalyst with chlorine, it is reported that the amount of chlorine in the process gas can vary from a partial pressure of chlorine of about 0.001 atmosphere to a pressure of about 2. atmospheres, and that it will not be necessary to treat the catalyst during each cycle.

   An examination of the regenerated catalyst periodically to determine the average crystal size of the platinum endow- whether or not it is necessary to increase the proportion of the dimension-

 <Desc / Clms Page number 25>

 lyser treated with a gas containing chlorine. If the average crystal size is greater than about 150 Angstroms, as can be determined by X-ray examination, the proportion of catalyst flowing through the chlorine treatment area should alor's be increased, and the proportion of catalyst not not passing through this area should be decreased.

   It is important to note in connection with the chlorine treatment that the catalyst should be substantially free of water. In other words, the catalyst should be substantially free of water when subjected to chlorine treatment in order to obtain the best results.



   The present invention utilizes the fluidized catalyst technique, and is further characterized in that the process operates at relatively low pressures, low rates of hydrogen recycle, and short processing times. It has been found that the catalyst which becomes fouled during the treatment phase cannot be fully regenerated with air alone and that it cannot be fully reactivated by subjecting the catalyst to prolonged soaking. in air at elevated temperatures and pressures, followed by the removal of deposits deactivated by oxidative regeneration.

   However, the spent catalyst can be brought back to a desired high degree of activity by subjecting it first to oxidative regeneration and then to the influence of a chlorine-containing gas for a short period of time. time.



  The chlorine treatment of the regenerated catalyst does not have to be carried out during each cycle. It is obviously required when the particles of the platinum group metal are transformed into large crystals at the. following their use in the process. In addition, as an addition of chlorine to the catalyst increases its hydrocracking activity and the volatility of the product, means are provided for adjusting the volatility of the product to the desired degree by controlling the amount of chlorine remaining on the catalyst after treatment.

 <Desc / Clms Page number 26>

 with chlorine and separation with air.

   During processing, however, chlorine may be carried away by the action of water in the feed, or formed during the process or during catalyst regeneration. In any case, the test results clearly show that the air regenerable platinum catalyst must be treated at least intermittently with the Chlorine Containing Gas, followed by regeneration, in order to maintain the activity. and the selectivity of this catalyst to a high degree.



   In summary, the present invention relates to improvements in the hydroforming of light naphtha in the presence of a platinum group metal.



   As noted, the present invention provides a process for improving the octane number of light naphtha boiling in the. range of about 110 to 250 F and is especially suitable for improving the octane number of naphtha fractions boiling in the range of about 150 to 200 F. Heavier naphtha boiling above From about 250 F up to about 430 F can also be processed according to the present invention, although there is no particular advantage in doing so.

   Heavier naphtha are generally more advantageously hydroformed by current high pressure hydroforming processes, using platinum or molybdenum wave catalysts and operating at pressures of about 200 pounds per pumice. square or more.

   The heavier naphtha lend themselves to common hydroforming processes and at the higher pressures employed a greater amount of coke is deposited on the catalyst, and the rate of catalyst deactivation is lower at these feeds. heavy. Cependatn, under certain circumstances,

   When it is desired to improve a large boiling range naphtha boiling both from the boiling ranges of light and heavy naphtha, it may be preferable to process this following naphtha

 <Desc / Clms Page number 27>

 
 EMI27.1
 the low-pressure platinum-based process of the present invention. In doing so, pre-fractionation of the feed and the provision of separate hydroforning installations can be avoided. at no pressure.
 EMI27.2
 1l: V'El) IC "TI C'l; j 1.

   The process of hy- iroforrnzn; J of hydrocarbon fractions, which comprises the contact of these fractions in admixture with a
 EMI27.3
 J. ' '' icLe to hydrogen, with a catalyst consisting essentially of a platinum group metal dispersed on alumina, at elevated temperatures and pressures below about 15 pounds per square inch, and the maintenance of these hydrocarbons in contact with the catalyst for a sufficient period of time
 EMI27.4
 to give a hydroforuing product of C¯ and higher, having a Research Clear octane number of at least 85.



   2. The process of claim 1 for the treatment of boiling naphtha fractions in the range of about.
 EMI27.5
 15Uo to 225 phew, which comprises contacting these mixed fractions with a gas rich in hydrogen, with a platinum catalyst on alumina, at temperatures of 800-975 C and at pressures. 50 to 100 pounds per square inch, and maintaining these hydrocarbons in contact with the catalyst for a period of
 EMI27.6
 te:! 1pS sufficient to give a C5 and higher hydroforming product having a Research Clear octane number of at least 65.



  3. The process according to claim "1, which comprises contacting the above fractions in admixture with a gas rich in hj'l ^ O .r¯P, with a fluidized bed of finely divided particles of platinum. on alumina, in a reaction zone, at temperatures of about 975 ouf and pressures of 50 to 100 pounds per square inch, and the irltien of the hydrocarbons in contact with it. catalyst for a period of time sufficient to give a product Cip: ¯j-drOfOr: ll.r¯; Cr. and more, having an octane number


    

Claims (1)

<Desc / Clms Page number 28> Research Clear of at least 85, 1 'continuously removed catalyst particles from a reaction zone, transfer of removed catalyst particles to a regeneration zone, combustion of inactivating carbonaceous deposits from catalyst particles therein. regeneration zone, and recycling the regenerated catalyst to the reaction zone. 4. The process of claims 1, 2 or 3 which comprises continuously removing catalyst particles from the reaction zone, transferring the removed catalyst particles to a regeneration zone, burning the inactivating carbonaceous deposits. catalyst particles in this regeneration zone, treating at least part of the regenerated catalyst with a halogen or a halogen compound, and recycling the regenerated catalyst and the regenerated and halogen-treated catalyst, to reaction zone. 5. The process according to claim 1, characterized in that charging from 200 to 1000 cubic feet of a gas containing hydrogen to said zone, the hydroforming temperature conditions are maintained in this zone, maintaining a pressure of 0 to 100 pounds per square inch in this zone, allowing the naphtha to remain in this zone for a period of time sufficient to achieve the desired conversion, recovering an improved octane product by good yields, and the spent catalyst is regenerated in a regeneration zone using an oxygen-containing gas. 6. The process of claim 5, wherein 200 to 500 standard cubic feet of hydrogen is fed to the reaction zone per barrel of oil. 7. The process of claim 5, wherein the catalyst residence urea in the reaction zone is 1 to 12 hours. 6. The method of claim 1, wherein <Desc / Clms Page number 29> the catalyst consists essentially of trampling on an alumina alcoholate. 9. The process according to any one of claims 3 to wherein the regenerated catalyst is treated with chlorine. 10. The process of any one of claims 3 to 9, wherein the catalyst after treatment with chlorine is treated with a separation gas to remove some of the chlorine associated with the catalyst. 11. The process of any one of claims 3 to 10, wherein about 0.2 to 1.25, by weight of chlorine is maintained on the catalyst at all times during use. 12. The process of claim 1 which comprises loading the naphtha into an elongated reaction zone of restricted cross-section, loading the platinum group metal catalyst into that reaction zone, and concurrent upward circulation of the reaction zone. Naphtha mixed with the gas containing hydrogen and catalyst, in this reaction zone, preferably at 5-15 feet per second. 13. The method of claim 1, characterized in that strongly heated shot is fed to the reaction zone to provide the heat required to sustain. EMI29.1 the hydroforming reaction.