US2983672A - Reforming with alumina-chromiaboria catalyst - Google Patents

Description

May 9, 1961 R. M. DoBREs ET AL 2,983,672

REFORMING WITH ALUMINA-CHRoMm-BORIA, CATALYST Filed April l. 1958 United States Patent O REFORMING WITH ALUMINA-CHRGNHA- BURIA CATALYST Robert M. Dobres, Silver Spring, Md., and Barton W. Rope, Mullica Hill, NJ., assignors to Socony Mobil Oil Company, Inc., a corporation of New York Filed Apr. 1, 1958, Ser. No. 725,555

6 Claims. (Cl. 208-136) This invention relates to a catalytic composite especially useful in reforming petroleum hydrocarbons. More particularly, the present invention is ydirected to an improved catalytic reforming process for obtaining gasoline of high octane number carried out in the presence of a catalyst consisting essentially of a co-gelled chromiaalumina composite of particularly defined composition combined in a particular manner with a specified minor proportion of boria and to the resultant catalytic composite.

Reforming operations wherein hydrocarbon fractions such as naphthas, gasolines and kerosene are treated to improve the anti-knock characteristics thereof, are well known in the petroleum industry. Reforming is generally carried out by contacting the hydrocarbon charge at an elevated temperature in the presence of hydrogen with "volume of hydrocarbon per hour per Volume of catalyst,

is between about 0.1 and about 10 and preferably between about 0.5 and about 4. In general, the molar ratio of hydrogen to hydrocarbon charge stock employed is between about l and about 20 and about 4 and about 12.

Hydrocarbon charge stocks generally subjected `to reforming comprise mixtures of hydrocarbons and particularly petroleum distillates boiling within theA approximate range of 60 F. to 450 F. which range includes gasolines, naphthas, and kerosene. The gasoline fraction may be a full boiling range gasoline or a selected fraction such as naphtha having an initial boiling point of between `about 150 Fr and about 250 F. and an end boiling point of between about 350 F. and about 425 F. Straight run gasolinas generally contain naphthe-nic hydrocarbons, particularly cyclohexane and related compounds and parailinic "hydrocarbons'which are usually of straight chain or slightly branch chain structure, as well as lvarying proportions of aromatic hydrocarbons. During reforming, a multitude of reactions take placeQincluding isomerization,` dehydrogenation, cyclization, etc., to yield a product of increased aromatic content. Thus, in reforming, it is desired to dehydrogenate the naphthenic hydrocarbons to produce aromatics, to cyclize the straight chain paraffinic hydrocarbons to form aromatics, and to elect a controlled type of cracking which is` selective both in quality and quantity.`

` Controlled or selective cracking is highly desirable during reforming since such willresult in a product of antiknock characteristicsl` As a `general `rl`1le,. tl`1e`Y lower preferably between i 'ice molecular weight hydrocarbons exhibit a higher octane number, and a gasoline product of lower average molecular weight will usually have a higher octane number. In addition, the isomerization and molecular rearrangement which occur during reforming also result in products having higher anti-knock characteristics. The splitting or cracking of carbon to carbon linkages must, however, be selective and should be such yas Vnot 'to result in substantial decomposition of normally liquid hydrocarbon into normally gaseous hydrocarbons. The selective cracking desired ordinarily involves removal of one or two lower alkyl groups, such as methyl or ethyl, from a given molecule in the form of methane or ethane. Thus, during reforming, it is contemplated that heptane may be converted to hexane, nonane to octane `or heptane, etc. Uncontrolled cracking, on the other hand, would result in decomposition of normally liquid hydrocarbons into normally gaseous hydrocarbons. For example, non-selective cracking of normal octane would ultimately lead to eight molecules vof methane.

Uncontrolled reforming, moreover, generally results in rapid formation and deposition on the catalyst of large quantities of a carbonaceous material generally referred to as coke The deposition of coke on the catalyst surface diminishes or destroys its catalyzing effect `and results in shorter processing periods with the accompanying necessity of frequent regeneration by burning the coke therefrom. In those instances where the activity of the catalyst is destroyed, it is necessary to shut down the unit, remove the deactivated catalyst, and replace it with new catalyst. Such practice obviously is time-consuming and inecient, imparting a greater over-al1 expense to the reforming operation.

The choice of catalyst for promoting reforming of hydrocarbons to gasolines of enhanced octane rating is dependent on several factors. Such catalyst should desirably be capable of effecting reforming in a controlled manner as discussed above to yield la product of improved anti-knock characteristics. The catalyst selected should further be resistant to poisoning and particularly to sulfur poisoningso .that sulfur-containing stocks may undergo reforming without the necessity of subjecting the same to a preliminary treatment for desulfurzation. The catalyst also should desirably be characterized by high stability yand be capable of easy regeneration, and the method for preparing such catalyst should be commercially attractive, requiring a minimum of equipment and processing stages.

ln accordance with the present invention, a catalyst of the `above-defined` characteristics has been discovered. Broadlyhythe present invention comprises reforming hydrocarbon mixtures and, particularly a naphtha fraction of petroleum in the presence of a catalystconsisting essentially of 'co-gelled chromia and alumina combined .with a minor proportion of boria. The invention further tion consisting essentially of ,co-gelled chromia-alumina y composited with boria have unexpectedly, been found to have improved reforming activity in comparison with chromia-alumina composites.

The method of reforming petroleum hydrocarbons in the presence of a co-gelled chromia-alumina composite combined with boria as described herein has been found to have certain advantages over the processes commercially available. The advantages obtained upon reforming with the present catalyst, while not fully understood, are believed to result from the method of preparation of the catalyst employed. The present catalyst initially involves the formation of a hydrogel of chromia and alumina preferably containing a chromia-alumina content of at least percent by Weight and thereafter combining the washed hydrogel with boria.

Boria may be combined with the co-gelled chromiaalumina by impregnating either the washed hydrogel or the dried and tempered chromia-alumina composite with a solution of a boron compound, followed by drying and calcining of the impregnated product. A preferred embodiment of the invention is the catalytic composite Vresulting from intimate admixing, for example, by ballmilling chromia-alumina hydrogel and a compound of boron, thermally decomposable to boron oxide, together, until a homogeneous composite is obtained and subsequentlydrying and calcining at an elevated temperature 'sufficient to effect decomposition of the compound of boron employed to boron oxide but not exceeding about In one embodiment chromia-alumina hydrogel containing, on a dry basis, about to about l45 percent by Weight of chromia and about 55 to about 85 percent by weight of alumina and having a solids content of at least about 10 percent by weight and generally in the approximate range of 10 to 30 percent by weight, i.e. containing about 70 to about 90y percent by weight of water, is ball milled with a finely divided solid boron compound, thermally decomposable to boron oxide, and subsequently dried and calcined at an elevated temperature. The amount of boron compound used may be varied depending on the catalyst composition desired `and on the particular compound of boron employed. Boric acid is particularly preferred as a source of the boria component. After intimately admixing by ball milling or other suitable means, the resulting composite is dried and calcined at a temperature sufiicient to elect decomposition of the boron compound employed but not in excessof about 1000" F. They composite catalyst consisting essentially of a co-gel of alumina and chromia combined with boria is thereafter ready for use.

Composites consisting of a major proportion of alumina, a minor proportion of chromia and a minor pro.-

portion of boria are suitably prepared in accordance with the above method. Catalysts having a composition of 10 to 30 percent by weight of chromia, 50 vto 89 per- Vcent by Weight of alumina and l to 20 percent by Weight of boria areV unusually effective for promoting reforming containing reforming catalyst. The co-gel of chromiaalumina is a true gel prepared by forming a hydrosol of chromiaand alumina and permitting said hydrosol to set to an all-embracing hydrogel. 'Ihe hydrogel is suitably in particle form prior to admixture with the boron compound. The particles may be of irregular size such as those produced by breaking up a previously set hydrogel or the particles may be of a uniform size and shape. Preferably, the alumina-chromia hydrogel particles are in the form of spheroids prepared by introducing the hydrosol in the form of globules into a waterirnmiscible medium wherein the hydrosol globules set to spheroidal hydrogel particles. It is particularly preferred to prepare a co-gelled catalytic composite of chromia and alumina from a hydrosol having an inorganic oxide content of at least about 10 percent by weight in accordance with the process described in U.S. Patent No. 2,773,839 to Stover and Wilson. Such process has been set forth in detail in the aforementioned patent. For convenience herein, the following is offered as a brief description of said process.

A true, all-embracing chromia-alumina hydrogel having a metal oxide product concentration of at least about 10 percent by weight and a relatively short gelation time, i.e.', less than 2 hours and preferably less than seconds, is prepared by intimately admixing an organic chromium salt, such as chromic acetate, and an alkali metal aluminate, such as sodium aluminate to produce a chromia-alumina hydrosol. The hydrosolv so formed is permitted to set to a hydrogel. 4The resulting hydrogel is thereafter subjected to aging and then waterwashed. The relative proportions of chromia and alumina may be Varied over a wide range. In accordance with the instant invention, however, the concentrations of reactants employed should be such as to afford a chromia-alumina hydrogel of composition within the range set forth hereinabove.

It is preferred, in preparing the above-described hydrogels, to use aqueous solutions of sodium aluminate and chromic acetate. Neither of these substances is a true chemical compound. The ratio of sodium to aluminum can be varied widely as can the ratio of acetate to chromium ion. Variation in the sodium to aluminum ratio of the aluminate solution requires compensating adjustment of the acetate to chromium ratio of the chromic acetate solution in order to achieve satisfactory gelation. Hydrosols capable of setting to hydrogels in less than about 20 seconds are particularly desirable for the production of beadlike spheroidal particles by methods well known in the art, for example, those described in patents to Marisic, such as U.S. Patent No. 2,384,946.

Quick-setting hydrosols of low viscosity which can be readily handled at bead-forming nozzles are those'prepared from sodium valuminate solutions which havek a sodium to aluminum mole ratio referred to as R of between 1 and 1.5. The acetate to chromium mole ratio in the chromic acetate solution employed should be not less than 2.8R-1-8 and not more than 4R-2.3

thermally decomposable solid boron compound, i.e. boric acid, represents a` preferred embodiment of the invention and has been found to afford an improved yield OfrefOrrnate of the same octane number as compared to `an voperation carried out under identical reforming conditions employing a chromia-alumina gel catalyst of 1 and preferably in the range of 4R-2.8 to LfR-2.4.

The control of the mole ratios discussed above is readily achieved in the manufacture of reactant'solutions. Chromium acetate is readily formed without introduction of undesirable extraneous materials by reducing sodium dichromate with glycolic acid in the presence of acetic acid as described more fully in U.S. 2,615,031.

- Sodium aluminate is conveniently prepared from caustic soda of 50 B. and aluminum trihydrate. At a sodium to aluminum mole ratio in the range of 1.25/1 to 1.5/ 1, the sodium aluminate is advantageously manufactured in an open agitated kettle at 22o-230 F. with` a reaction time of 1 to 3 hours. Solutions having a lower mole ratio downto about 1.0/1 are made in an autoclave Vat 2410-300or F. vand 10 to 30 pounds per square inch gauge at the same reaction time. Sodium aluminate solutions having a low sodium to aluminum ratio less than 1.3 are relatively unstable and may be stabilized `hyd-rides,` such as di-borrane.

by the addition of such organic materials as glycerne, starch, sugar, and the like.

Thus, chromia-alumina hydrogels having a short time of set and a high solids content generally between about and about 30 percent by Weight may readily be prepared by controlling the sodium to aluminum mole ratio of the sodium aluminate solution employed and the acetate to chromium mole ratio of the chromic acetate solution. The specific ratios employed will depend upon the particular composition of the chromia-alumina hydrogel desired.

Temperature, acidity, and product concentration are interrelated variables effecting gelation and within the limits in which formation of hydrogels occurs they control gelation time. In general, the other factors can be controlled to achieve gelation at any practical solution temperature. Thus, temperatures from 30 F. to 150 F. are suit-able. Best gelation times are experienced at temperatures between about 120 F. and about 140 F. The pH of the chromia-alumina hydrogels is generally between 10 and 13. For bead formation, a pH of about l2 yields excellent results.

For the production of chromia-alumina hydrogel beads, preparation is carried out substantially the same as that described in the above noted Marisic patent for producing silica-alumina beads. `Thus, a chromium acetate solution and a sodium aluminate solution are contacted in a mix-ing nozzle and discharged onto the apex of a dividing cone from which la number of small streams flow into a column of water-immiscible liquid. The temperature of said water-immiscible liquid is desirably maintained constant by circulation through a heat exchanger outside the bead-forming tower.

The freshly formed chromia-alurnina hydrogel above described is subject to a loss of aluminum as sodium aluminate if immediately washed with water. This tends to weaken the hydrogel to such an extent that it disintegrates in the washwater. That adverse effect can be avoided by immediately treating the freshly formed hydrogel in a slightly alkaline `aqueous medium.` This is generally accomplished by bringing the freshly formed chromia-alumina hydrogel into contact, withl an aqueous solution of an` ammonium salt of a mineral acid or a mineral acid or a mixture of such salt and acid. In a typical operation, the freshly formed hydrogel beadsare `sluiced out of the forming tower with oil. The hydrogel beads are then separated from theoil and treated with a Z0 percent by weight solution of ammonium sulfate. The solution is advantageously kept at @a pH of 8.0 to 9.5 by the addition of sulphuric acid. lt is advisable to maintain a solution of `this type in contact with the freshly formed hydrogelfor some time after formation. For example, the solution .-is reoirculated through the freshly formed hydrogel or otherwise maintained in contact therewith for a period of,` from about, 2 to about 24 hours after forming in order to iixthe alumina. Such treatment of the freshly formed hydrogel is designated herein as aging After the `aging treatment, the chromialalumina hydrogel is water-washed free of anions introduced during aging. The washedhydrogel is thereafter ready for compositing with boria. The combination of boria with the chromia-alumina hydrogel` involves intimate adm-ixture with said hydrogel` of a solid boron compound, such as boric acid,decomposable by heating at a temperature of less than 1000 F. to boron oxide (B203), While boric acid, due to its availability and ease of decomposition, is preferred, other suitable boroncoinpounds, decomposablefto boron oxide under the conditions employed includeboric. acid esters of alcohols, such as triv ethyl -borate and-tri-lmethyl borate; boric acid esters of poly-hydric alcohols, such `as glycerol borate and `boron The boron compound `is preferably in the form of a finely pulverized or powdered about 70 to 90 percent by weight of water, is intimately mixed with the solid boron compound in the `above indicated nely divided state. Vigorous and thorough ad- `mixture of the components is necessary to achieve. a

l period will, of course, depend on the relative amounts of each of the components as well as on the total mass of material being treated. Generally, however, the mixing period will be within the range 'of 4 to 20 hours.

At the `completion of the mixing operation, the resulting composite, either with or without intermediate formation of the same into particles, is slowly heated to an elevated temperature generally in the range of 800 to 1000 F., which temperature is sufficient to eifect decomposition of the boron compound present to boria. The rate of heating should be comparatively slow, generally not in excess of 10 F. per minute. It is essential to the success of the present invention that the temperature to which the composite of chrorna, alumina and boria is heated should not exceed about 1000 F. if such temperature is substantially exceeded, fusion of the boria component takes place with accompanying marked loss of `catalytic activity. During the period of heating the wet catalyst, the atmosphere surrounding such catalyst should be desirably free of oxygen. This may be accomplished by maintaining an inert atmosphere in contact with the catalyst during the course of heating. In a preferred embodiment of the process, a non-oxidizing atmosphere may be provided by permitting the steam produced from the moisture contained in the wet catalyst to blanket the .same during heat treatment. The resulting catalyst is a composite consisting essentially of chromia-alumina gel intimately combined with a catalytically effect amount of boria.

The formation, compositing and subsequent heat treat- .ment of chrornia-alumina-bonia composite in accordance with this -invention may be carried out either as a batch or continuous operation. Thus, the chro-mia-alumina hydrogel particles after formation, aging and washing may be ball milled or otherwise intimately mixed either on a batch basis or as part of a .continuous operation. Heat treatment of the composited material may also be effected in a batch .or continuous manner Generally, for commercial production, it is preferred to carry out the manufacture of the present chromia-alumina-boria catalyst' on a continuous basis. A suitable continuous method of operation is shown in the form of a schematic ow diagram in Figure l of the attached drawing.

Referring more particularly to Figure 1, a mixing nozzle 10 into which are conducted aqueous streams of sodium aluminate and chrornic acetate, is mounted over a conical divider 11` which is located-near the surface of the water-immiscible liquid 'in forming tower 12. The colloidal solutions from which the hydrogel particles are formed are mixed and admitted through nozzle 10- to the top of the divider 11 which generally is fluted and serves to divide the stream of hydrosol into a plurality of smaller streams which enter the column of water immiscible suspending liquid in tower 12 as: small droplets.

`The length of the column of suspending liquid and the gelation time of the sols are so regulated that the droplets will gel before passing out of the forming tower.

`Suspending liquid is continuously supplied through inlet Ydraining section and a iiushing section. The hydrogel material. The chromia-alumina hydrogel, containing particles initially are conducted through the draining section wherein loosely held oil drains from the particles into collecting pan 17. The oil so collected, thereafter passes through conduit 18 and is recycled to forming tower 12 by way of pump l19 and conduit 20. The hydrogel particles on the conveyor which have been drained-of loosely held oil pass into the flushing section and there are flushed or sprayed with a suitable washing fluid through a spray 21. The resulting mixture of oil and washing iluid is collected in pan 22 and thereafter flows through conduit 23 to settling tank 24. The oil contained in such mixture is removed from the lower portion of tank 24 and passes through conduit Z5 to pump 19 and is then recycled through conduit 20 to forming ltower 12. The washing fluid separating in the upper portion of tank 24 is withdrawn through conduit 26 and recycled to spray 21 for further `use in deoiling. Washing fluid make-up, as needed, is introduced through inlet 27. The chromia-alumina hydrogel particles, after being deoiled, are discharged from the conveyor belt into a flume 28 and are conducted to againg tank 29 in with the hydrogel particles are subjected to aging treatment in an aqueous media, such as an aqueous ammonium sulfate solution.

After the aging treatment, the chromia-alumina hydrogel particles are removed from tank 29 through conduit 30 and conducted to washing tank 31 in which the hydrogel particles are water-washed free of anions introduced during aging. The washed hydrogel is then removed from washing tank 31 through conduit 32 and introduced to ball mill 33. Boric acid, in finely divided particle-form, is also introduced through inlet 34 to ball mill 33. The washed chromia-alumina hydrogel and boric acid are intimately admixed in the ball mill. The ball-milled product is then conducted to an extruder 35 wherein it is extruded to particles of desired size. The particles, so formed, are conducted to a kiln 36 in which the composite particles are dried and calcined at a temperature not in excess of about 1000 F. Water vapor removed from the particles passes out of the kiln through outlet 37. The product of chromia-alumina-boria catalyst passes from the kiln through outlet 38.

An alternate method of preparation for the cogelled chromia-alumina composite combined with boria as described herein involves contacting the aged, water-washed chromia-alumina hydrogel prepared as hereinabove described with an aqueous solution of a water-soluble boron compound. In this method of operation, the period of impregnation will generally be within the range of 2 to 48 hours. The impregnated composite is thereafter dried, preferably in superheated steam at a temperature of 220-250 F. and subsequently tempered at an elevated temperature not exceeding about 1000 F. Also, in some instances, it may be desirable to prepare the catalyst by purging the dried, tempered chromia-alumina gel particles under atmospheric pressure with steam at a temperature above 24.12 F., thereby replacingthe air which normally occupies the gel pores with steam.y The gel particles'sotreated may 4then be brought into contact with the aqueous impregnating solution ofboron compound without encountering gel breakage. and impregnation thereof effected. Also, it is possible to prevent gel breakage ofthe dried, tempered chromia-alumina gel particles by evacuating the` same before contacting With the impregnating solution. i-The advantage of the present catalyst over those of the prior art is thata homogeneous active' catalytic surface of chromia-alumina-boria is obtained and that .the activityin reforming petroleum hydrocarbons of the yresultant three-component composite is distinctly improved as compared with chromia-alumina composite which had not Vbeen composited lwith boria. Thus, .the catalyst de- 8 It would appear that the advantages derived in reforming with the present catalyst are due to the specific promoting effect of the specified quantities of boria when the same are combined with chromia-alumina cogel of the above-recited composition range.

While certain details referred to `in the foregoing description have been directed to catalyst preparation in which chromia-alumina gel is employed in the form of spheroidal particles, it is to be realized that it is within the purview of this invention to use chromia-alumina gels of any other desired form or shape.

The following non-limiting illustrative examples will serve more specifically to point out 'the process of the invention and the improved results in activity obtained with the catalyst prepared in accordance with said process.

Example 1 A chromia-alumina hydrogel was prepared from the following reactants:

Solution A: 47.5 pounds sodium aluminate made up to a volume of 10 gallons with distilled water;

Solution B: 48 pounds, chromic acetate, the acetate to chromium ratio of which is adjusted within the approximate range of 2.6 to 2.8 and then made up to a volume of 13 gallons with distilled water, providing a solution containing 0.92 mole CrzOa per liter.v

Solutions A and B were pumped separately under pressure through heating coils to an ecient mixing nozzle. The solutions were heated to about 110 F. and mixed in equal volumes at a total rate of 1200 cc. per minute. The resulting stream of hydrosol flowed over a divider into a column of D.T.E. (diesel turbine engine) light oil. The hydrosol set to beads of hydrogel and the resulting hydrogel beads were sluiced from the bottom of the forming tower with a 20 percent by weight aqueous solution of ammonium sulfate. The sluicing solution was maintained at a pH of 8.5 by the addition of sulfuric acid. Since the pH of the hydrogel was about 10.5, it was necessary to add sulfuric acid to the sluicing solution in order to maintain the pH at 8.5. The bead hydrogel was aged for 24 hours in the same solution that was used to sluice from the forming tower. After aging, the gel was Washed until v a sulfate-free wash Water was indicated. The washed hydrogel had a product concentration of 21 percent by weight, and contained, on a dry basis, 33.5 percent by weight chromia and 66.5 percent by weight alumina. The hydrogel was thereafter ball-milled, dried at 260 `to 280 F. for 16 to 2() hours and then calcined in air for 16 hours at 1000 F.

Example 2 The washed chromia-alumina hydrogel prepared as in Examplevl in -an amount of 3000 grams was ball-milled scribed herein, comprising Van intimate composite of f :position which had not undergone combination with boria.

with 48.4 grams of powdered boric acid. The resulting composite was dried at 260 to 280 F. for 16 to 20 hours and then calcined in Iair for 16 hours at 1000 F. The

resulting composite contained 63.4 percent by weight alumina, 31.9 percent by weight chromia and 4.7 percent by weight boria. y

Example 3 The catalyst of Example 1 was used in reforming a blend of 50/50 molar n-.heptane and cyclohexane. The catalyst was sized to 14-25 mesh before charging tothe reactor. Fifty cubic centimeters (49.84 grams) of the catalyst was placed in 'the catalyst zone of a reactor and activated by allowing a stream of hydrogen to pass over it at atmospheric pressure for 16 hours while holding the catalyst bed at 1000 F. In the reforming process before starting tto charge the reactants to the catalystjzone, the temperature of thecatalyst was brought to about 860,F. The blend of n-heptane and cyclohexane was passed downwardly over the catalyst bed at a liquidl hourly space velocity of l. Hydrogen was mixed with the hydrocarbon feedbefore it entered the reactor in theA ratio of 6 mols of hydrogen to 1 mol of hydrocarbon charge. The total `mass spectrometer.

9 pressure within the system was held at 100 p.s.i.g. The reactants were passed over the catalyst during a minute pre-run period, the products being discarded. Then a 30 minute balance run was made. Temperature in the catalyst -bed was measured by means of a movable coaxial Ithermocouple. IDuring the balance run, the liquid was 10 catalyst and 22.5 percent fresh catalyst were used to reform the /50 molar n-heptane/cyclohexane blend, according to the procedure of Example 3. The temperatures employed were 856, 917, 969, and 1021 F.

The results of reforming in accordance with the above Examples 3, 4, and 5 are shown in Table I below:

TABLE I Reforming to mol Percent n-Heptane Converted Example Catalyst Temp., l-C7 Toluene CH Con- MCP Benzene Cri-C2 Cri-C4 F. Yield, Yield, version, Yield, Yield Yield, Yield, n-C'z Chgd. CH Chgd. Feed Chgd.

Mol. Mol. Mol. Mol. Mol. Mal. Mol. Percent Percent Percent Percent Percent Percent Percent Chromia-Alumina Catalyst 1, 00S 5 14 95. 5 2 96 13 of Example 1. Chromia Alumina Borla 981 14 13 98 1 96 17. 5 10 Catalyst of Example 2. Catalyst of Example 2 988 12. 5 11. 5 94 12 89 16. 5 11.5

(77.5% Regenerated from Ex. 4 and 22.5% fresh) Reforming at 950 F.

Example Catalyst n-C1 Coni-C1 Toluene CH MCP Benzene Cl-l-Cz Cyl-C4 version, Yield, Yield Conv., Yield, Yield Yield, Yield, n-C Chgd. CH Chgd. Feed Chgd.

Mol. Mol. Mol. Mol. Mol. Mol, Mol. Mol. Percent Percent Percent Percent Percent Percent Percent Percent 3 Chromia-Alumina Catalyst 18 2 72 66 2. 5

of Example l. 4 Chromia Alumina Boria 40 13.5 6.5 92 2. 5 86.5 9. 6 5 Catalyst of Example 2. l

5 Catalyst of Example 2 30 12 4 82 12 70 7. 5 5

(77.5% Regenerated from Ex. 4 and 22.5% fresh).

O1+Cq=sum of hydrocarbons containing 1 or 2 carbon atoms per molecule. Ca+04=sum of hydrocarbons contaiung 3 or 4 carbon atoms per molecule.

`tion. The overhead from this distillation and the two gas samples were given ya complete component analysis by A portion of the residue was acid treated to remove olens. The untreated portion was submitted for analysis, as Well as the acid treated portion. Ultimately, a complete analysis of the run products was obtained. Four such runs were ma'de at laverage catalyst temperatures of 8,55, 906, 959 and 1017 F. In each ease, a pre-run preceded the balance run. The reforming results obtained are `set forth hereinafter.

Example 4 The catalyst from Example 4 was regenerated by burn- 'ing oiI coke at 900 to 1000 F. Fifty centimeters (45.64 grams) of catalyst `having the composition of the catalyst oli-Example 2 and comprising 77.5 percent regenerated In the above Table I (Examples 3 and 4), it is clearly shown that the boria-promoted catalyst is` more active for the conversion of n-heptane and cyclohexane than the unpromoted chromia-alurnina. The fresh boria-promoted catalyst converted 60 percent of the n-heptane at 27 F. lower temperaturetl'ian chromia-alumina. Furthermore, the addition of boria tochlromia-alumina nearly doubled `the yield of isoheptane. At 950 F. both n-heptane conversion and cyclohexane conversion were strongly enhanced by promotion with boria. The benzene yield increased from 66 to 86 percent. Example 5 illustrates the effect of regeneration on the chrorniaealumina-boria catalyst.` The temperature required for conversion of 60 'percent of the normal heptane was increased 7 F., while at 950 F. n-heptane and cyclohexane conversion decreased about l0 percent. Nevertheless, the regenerated catalyst was more .active than the fresh unpromoted chromia-alumina catalyst.

Example 6 The catalyst of Example l was used to reform the naphtha petroleum fraction having lan octane number of 67 and a boiling range `of between about 180 and about 390 F. The charge was reformed to 98 octane number (CFRR-l-S cc. TEL), at a liquid hourly space velocity of 1, a hydrogen to hydrocarbon mole ratio of 6 and a pressure of p.=s.i.g.

Example 7` The results of reforming, in accordance with the above Examples 6 and 7 `are shown in Table II below:

ing in the gasoline range which comprises contacting the same under reforming conditions with a catalyst consist- TABLE II Gasoline, Vol. Percent Chg. Iso/normal Wt. Percent C4 Req., Chg. Example Catalyst Temp., Vol. F. Percent l# C4l Cri-c Ce-l- Charge C4 C5 lry Coke Chromia-Alumina (Catn- 993 83. 9 83. 4 75. 4 68. 5 0.5 0.51 0. 77 13. 4 0.10

lyst of Example 1). Chrorna-Alumina-Boria 972 84. 0 81. 9 75. 7 69. 1 2. 1 0. 40 0. 57 13. 8 0. 63

(Catalyst of Example 2) The results of the above Table II clearly illustrate the eifect of the addition of boria to chromia-alumina on the reforming catalyst activity. The boria-promoted catalyst was about 20 F. more active at 98 octane number than the unpromoted chromia-alumina. lThe improvement in activity of the present catalyst as compared with a chromia-alumina catalyst is shown in Figure 2 of the attached drawing. This ligure shows the laver-age temperature required to produce reformate of various octane ratings using chromia-alumina (33.5 percent Cr2O3-66-5 percent' A1203) and a catalyst of the present invention containing a small amount of boria in combination with the above chromia-alumina (63.4 percent by weight Al2O3-'-31.9 percent by Weight Cr2O3-4-7 percent by weight B203).

=In addition to reforming hydrocarbon mixtures falling in the gasoline range, the catalyst of the present invention is useful in catalytioally promoting various other hydrocarbon conversion reactions including, by way of example, the isomerization of parains and dehydrogenation of naphthenes. It is accordingly to be understood that the above description is merely illustrative of the preferred embodiments of the invention of which any variations may be made within the scope of the following claims by those skilled in the art without departing from the spi-rit thereof.

We claim:

l. Aprocess for reforming a petroleum distillate boiling within the approximate range of 60 F. to 450 F. which comprises ycontacting the same at a temperature `between about 700 F. and about 1000 F. yat `a liquid hourly space velocity between about 0.1 and about in vthe presence of hydrogen under a pressure between about 100 and about 1000 pounds per square inch gauge and a mola-r ratio of hydrogen to hydrocarbon between about liiand about with a catalyst consisting essentially of chromia, alumina and boria prepared by forming a chromia-alumina hydrogel having a solids content consisting essentially of a major proportion of alumina and a minor proportion of chromia and containing between about 70 and about 90 percent by weight of water resulting from mixing aqueous solutions of sodium ialuminate and ychromic acetate to yield a hydrosol, controlling the 'sodiumto aluminum ion ratio and the acetate to chromium ion ratio, in said solutions to effect rapid gelation Vof said hydrosol to a hydrogel, aging the hydrogen so obtained in a mildly alkaline aging medium, washing the aged hydrogel, intimately combining the washed hydrogel with boric acid, drying andcalcining the resulting composite at a temperature not in excess of 1000 F. to yield a chromia-alumina-boria catalystpconsisting essentially of l0 to 30 percent by weight of chromia, 50 to 89 percent by weight of alumina and l to 20 percent by weight of boria. r i 1 2. A processfor reforming a hydrocarbon mixture boiling essentially of chromia, alumina and boria prepared by forming a chromia-alumina hydrogel having a solids content consisting of a major proportion of alumina and a minor proportion of chromia land containing between about 70 and about 90 percent by weight of water resulting from mixing aqueous solutions of sodium aluminate and chromic `acetate to yield a hydrosol, controlling the sodium to aluminum ion ratio and the acetate to chromium ion ratio in said solutions to elfect rapid gelation of drying and calcining the resulting composite at a temperature not in excess of 1000 F. to yield a chromia-aluminaboria catalyst consisting essentially of 10 to 30 percent by weight of chromia, 50 to 89 percent by weight of alumina, and 1 to 20 percent by weight of boria.

3. A method for preparing a catalytic composite of chromia, alumina and boria which comprises forming a chromia-alumina hydrogel having a solids content consisting of a major proportion of alumina and a minor proporjtion .of chromia and containing between about 7 0 Vand about percent by weight of water resulting from mixing aqueous solutions of sodium aluminate and chromic acetate to yield a hydrosol, controlling the sodium to aluminumion ratio and the acetate to chromium ion ratio in said solutions to effect rapid gelation of said hydrosol Vto a hydrogel, aging the hydrogel so obtained in a mildly alkaline aging medium, washing the aged hydrogel, intimately combiningV the washed hydrogel with a boron compound thermally decomposable to boria, drying and calciningtherresulting composite at `a temperature not in excess of 1000 F. to yield a chromia-alumina-boria catalyst consisting essentially of 10 to 30 percent byrweight of chromia, 50 to 89 percent by weight of alumina, and 1 to 20 percent by weight of boria. f

4. A method for preparing. ar catalytic composite of chromia, `,alumina and boria which comprises forminga chromia-alumina hydrogel having a solids content consisting essentially of a major. proportion of alumina and a minor proportion of chromia containing between about 70 and 4about 90 percent by weight of water resulting from mixing aqueous solutions of sodium aluminate and chromic acetate to yield a hydrosol, controlling the sodium to aluminum ion -ratio and the acetate to chromium ion ratio in said solutions to eifect rapid Lgelaton of said hydrosol to a hydrogel, aging the hydrogel so obtained in a mildly alkaline aging medium, washing the aged hydrogel, ball milling said hydrogel with boric acid for a sufficient period of time to effect a resultant homogeneous product, drying and calcining the resulting composite at a temperature not in excess of 1000 F; to yield a chromia-alumina-boria catalyst consisting essentially of 24 to` 30 percent by weight of chromia, 60 to 73 i percent by weight of alumina and 3 to 10 percent by weight References Cited in the le of this patent of boria.

5. A catalyst composition consisting essentially of 10 UNITED STATES PATENTS to 30 percent by Weight of Ch-rOma, 50 t0 89 Percent by 2,098,959 Frey et 'al Nov. 16, 1937 weight of alumina and 1 to 2O percent by weight of boria, 5 2,288,320 Morey June 30, 1942 resulting from the method of preparation set forth in 2,404,024 Baie et al July 16 1946 Claim 3- 2 523 686 E 1 s 6 6- A catalyst meting essentially of 24 w 30 Percent 656304 Nhzgggezgfi; if; i322 by welght 0f chromla, 60 t0 73 percent by Welght 0f 2,773,837 Gutzeit et al Dec. 11, 1956 alumina and 3 to 10 percent by weight of boria, resulting 10 from ythe method of preparation set forth in claim 4. 2773845 Stover et al Dec' 11 1956

Claims (1)

1. A PROCESS FOR REFORMING A PETROLEUM DISTILLATE BOILING WITHIN THE APPROXIMATE RANGE OF 60*F. TO 450*F. WHICH COMPRISES CONTACTING THE SAME AT A TEMPERATURE BETWEEN ABOUT 700*F. AND ABOUT 1000*F. AT A LIQUID HOURLY SPACE VELOCITY BETWEEN ABOUT 0.1 AND ABOUT 10 IN THE PRESENCE OF HYDROGEN UNDER A PRESSURE BETWEEN ABOUT 100 AND ABOUT 1000 POUNDS PER SQUARE INCH GAUGE AND A MOLAR RATIO OF HYDROGEN TO HYDROCARBON BETWEEN ABOUT 1 AND ABOUT 20 WITH A CATALYST CONSISTING ESSENTIALLY OF CHROMIA, ALUMINA AND BORIA PREPARED BY FORMING A CHROMIA-ALUMINA HYDROGEL HAVING A SOLIDS CONTENT CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF ALUMINA AND A MINOR PROPORTION OF CHROMIA AND CONTAINING BETWEEN ABOUT 70 AND ABOUT 90 PERCENT BY WEIGHT OF WATER RESULTING FROM MIXING AQUEOUS SOLUTIONS OF SODIUM ALUMINATE AND CHROMIC ACETATE TO YIELD A HYDROSOL, CONTROLLING THE SODIUM TO ALUMINUM ION RATIO AND THE ACETATE TO CHROMIUM ION RATIO IN SAID SOLUTIONS TO EFFECT RAPID GELATION OF SAID HYDROSOL TO A HYDROGEL, AGING THE HYDROGEN SO OBTAINED IN A MILDLY ALKALINE AGING MEDIUM, WASHING THE AGED HYDROGEL, INTIMATELY COMBINING THE WASHED HYDROGEL WITH BORIC ACID, DRYING AND CALCINING THE RESULTING COMPOSITE AT A TEMPERATURE NOT IN EXCESS OF 1000*F. TO YIELD A CHROMIA-ALUMINA-BORIA CATALYST CONSISTING ESSENTIALLY OF 10 TO 30 PERCENT BY WEIGHT OF CHROMIA, 50 TO 89 PERCENT BY WEIGHT OF ALUMINA AND 1 TO 20 PERCENT BY WEIGHT OF BORIA.

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