US3360456A

US3360456A - Process for the hydrocracking of hydrocarbons in two stages to produce gasoline with a reduced consumption of hydrogen

Info

Publication number: US3360456A
Application number: US496166A
Authority: US
Inventors: Joseph K Kosiba; Rice Theodore
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1965-10-14
Filing date: 1965-10-14
Publication date: 1967-12-26
Anticipated expiration: 1984-12-26

Description

United States Patent 3,360,456 PROCESS FOR THE HYDROCRACKING 0F I-IY- DROCARBONS IN TWO STAGES T0 PRODUCE GASOLINE WITH A REDUCED CONSUMPTION OF HYDROGEN Joseph K. Kosiba, Port Arthur, and Theodore Rice, Beaumont, Tex., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing. Filed Oct. 14, 1965, Ser. No. 496,166 3 Claims. (Cl. 20859) Our invention relates to a two-stage hydrocracking process for the production of lower boiling materials, such as gasoline, with a reduced consumption of hydrogen.

It has been suggested previously in the art that conversion of higher boiling hydrocarbon materials, such as furnace oils and gas oils, into lower boiling materials, such as gasoline, could be achieved by hydrocracking processes. These suggested procedures generally involve contacting higher boiling hydrocarbon with hydrogen at hydrocracking temperatures and pressures in the presence of a dual component hydrocracking catalyst, i.e., wherein one component has hydrogenation activity and the other component has hydrocracking activity. Catalysts of this type are well-known in the art and can comprise, for example, Group VI and VIII metals supported on refractory metal oxides. These catalysts are known to crack randomly both alkyl and aryl hydrocarbon materials thereby effecting a general reduction in the boiling range of converted material. It has also been suggested in the art that certain economies might be effected in utilities required for the conduct of such processes if the operation were conducted in two stages. The theory upon which such two-stage operations are predicated would appear to be that the more easily convertible materials could be hydrocracked in a first stage operating at a low temperature and such converted material re moved therefrom, while the more difficulty convertible components could be hydrocracked in a second stage employing a substantially higher temperature. The purported advantage to be gained from a two-stage process of this type is that a certain portion of the conversion can be attained at a sufficiently low temperature that a savings in over-all heating requirement of the process is realized.

'While such previously suggested hydrocracking processes have been effective in the production of lower boiling components in good yields, such procedures, both single stage and multistage, heretofore have been characterized consistently by high hydrogen consumption. Although this relatively high hydrogen consumption can be tolerfrom about 750 to 1000 F., a pressure in the range from about 250 to 750 p.s.i.g., a liquid hourly space velocity (LHSV) in the range from about 0.5 to 4.0 volumes of hydrocarbon charge stock per hour per volume of catalyst with a hydrogen consumption of less than 200 standard cubic feet of hydrogen per barrel of hydrocarbon charge stock while in the presence of a hydrogenation catalyst composited with an activated alumina having less than about percent of its pore volume in pores larger than 70 A radius. In this first stage the operating conditions employed are selected from the ranges set forth above so as to provide a conversion from about 30 to 60 percent by volume to materials boiling below the initial boiling point of the charge stock. From the efiluent of this first stage are separated a first gasoline fraction boiling up to about 400 F. and a fraction boiling above 400 F. The fraction boiling above 400 F.

is then passed to a second stage where such fraction is hydrocracked under more conventional conditions. In this second stage the 400 F.+ fraction is contacted with hydrogen at a temperature in the range from 600 to 800 F., a pressure in the range from 1000 to 3000 p.s.i.g., a LHSV from 0.5 to 2.0 and a hydrogen consumption of at least 1000 standard cubic feet per barrel of 400 F.+ fraction while in the presence of a dual component hydrocracking catalyst. The particular operating conditions employed in this second stage are selected from the above ranges so as to effect a conversion of at least 70 percent by volume to materials boiling below 400 F. A second gasoline fraction boiling up to 400 F. is then separated 4 from the second stage effluent. The first and second gasoated in refineries where an abundance of hydrogen is H available at low cost from other refinery processes, such as for example, naphtha reforming, such previously suggested hydrocracking procedures are less desirable from an economic view point in a refinery where surplus hydrogen is scarce and operation of the previously suggested processes would require an auxiliary hydrogen manufacturing plant.

Our invention relates to a novel two-stage hydrocracking process wherein the hydrogen consumption is substantially lower than that obtained with the conventional one-stage hydrocracking process previously suggested by the art and the gasoline octane number is significantly higher than is produced by the previously suggested process. The process of our invention comprises hydrocrack ing in a first stage a hydrocarbon stock boiling in the range from about 400 to 850 F. and containing less than about 5 ppm. nitrogen under substantially dehydrogenative conditions. This hydrocracking in the first stage is accomplished by contacting the hydrocarbon charge stock with hydrogen at a temperature in the range line fractions can then be blended so as to provide a total gasoline product.

Suitable charge stocks to the first stage of our process include any petroleum hydrocarbons boiling generally in the range from 400 to 850 F. and containing less than 5 ppm. nitrogen such as, for example, straight run light furnace oils, full range straight run furnace oils and gas oils. The stocks charged to the first stage of our process can also be aromatic stocks, i.e., containing as much as to percent aromatic hydrocarbons. Advantageously, the hydrocarbon charged to the first stage can also comprise a large proportion, above about 30 or 40 percent by volume, of hydrocarbon components containing at least one saturated ring.

The support for the catalyst employed in the first stage i of our process must be an activated alumina which has has been deposited thereon. These alumina supports are also generally characterized by a surface area greater than square meters per gram, a sodium content of less than 0.05 percent and less than about 0.05 percent sulfur in the form of sulfates. Aluminas of the type required in the first stage of our process are available commercially, such as for example, H-44 alumina manufactured by the Aluminum Company of America. Alternatively, these aluminas can be prepared from appropriate starting materials in any convenient way. These aluminas can be prepared, for example, in accordance with procedures described in US. Patents Numbers 3,151,939, 3,151,940 and 3,188,174. Briefly, in accordance with the methods disclosed in the above-mentioned patents, alumina carriers or supports useful in the present invention can be prepared by drying and calcining a material predominantly composed of aluminum hydroxide containing from 1.2 to 2.6 moles of water of hydration. A wide variety of aluminum salts are suitable for preparation of .this specific aluminumhydroxide, such as, for example,

' or lower water of hydration contents than the 1.2 to 2.6

moles per mole of A1 For the same reason care should be exercised during neutralization so as to avoid a localized higher or lower pH value. The aluminum hydroxide for-med as described is separated from the aqueous mixture, washed to remove any undesirable salts and is then dried to remove entrained or mechanically held water before a stable product is obtained. Drying can be eifected at an elevated temperature above about 170 F. To avoid undesirable transformation of the aluminum hydroxide into a form having a higher or lower water of hydration content such drying temperatures can be maintained throughout the above-mentioned precipitation and washing steps until the drying is completed. Alternatively, the transformation of the precipitated aluminum hydroxide into less desirable forms can be avoided by effecting both precipitation and drying with promptness. Ordinarily the precipitation and drying should be accomplished within a period of at most 24 hours and preferably within 4 to 8 hours or less when this expedient is employed. According to another technique the undesirable transformation can be retarded or avoided by conducting the precipitation in the presence of an acetate ion or by employing a bufiered precipitating solution. After drying to remove the entrained, adherent or mechanically held water, the aluminum hydroxide is calcined to remove water of hydration and the activated alumina obtained thereby is I useful as a carrier for the hydrogenation catalyst of the first stage of our process.

The activated alumina carrier having the pore size distribution required in our invention is composited with a hydrogenating component of the kind customarily employed in a hydrocracking catalyst such as Group VI and VIII metals, the oxides or sulfides thereof, such as, for example, nickel, cobalt, platinum, palladium, molybdenum,-nickel sulfide and tungsten sulfide. Any conventional procedures for compositing porous carriers to form a multi-component catalyst can be used to prepare the catalyst required by our invention. Ordinarily we prefer to impregnate the activated alumina with an aqueous solutionof a salt of the hydrogenating metal followed by drying and calcining. If two hydrogenating components are to be employed, such as a nickel-tungsten mixture, it

is advantageous to deposit first one of the components, such as tungsten, followed by drying and calcining and then impregnate with an aqueous solution of a salt of the other metal, such as nickel, followed by a second drying and calcining. Other known procedures such as simultaneous impregnation of both metal components can s also be employed. See for instance US. Patent 2,703,789,

of. McKinley and Pardee. Between about 0.5 and 35 percent by weight of hydrogenating component may be incorporated into the alumina support. In the case of a nickeltungsten catalyst, between about 3 and 25 percent by weight of tungsten and between about 0.5 and 10 percent by weight of nickel can be employed. Although We may refer to the metal components as sulfides or in sulfided form this is not to be taken as an indication that they are necessarily present as conventional sulfides since the sulfur component may be present in other combinations such as, for example, nickel thio-tungstate. This catalyst composite can also be promoted with a halogen, such as fluorine, present in an amount from about 0.5 to about 5 percent by weight based upon the total catalyst composite. The presence of from about 1 to about 15 percent silica can also be employed to promote the catalyst employed in the first stagev of our process.

The importance of employing in the first stage of our process a catalyst supported on a carrier having the abovedescribed pore size distribution can be demonstrated by hydrocracking a highly aromatic, refractory, fluid catalytically cracked furnace oil distillate which is suitable for use as a feed stock herein using catalysts prepared from aluminas having a variety of pore size distributions. Thus, employing (1) an activated alumina prepared by drying and calcining an aluminum hydroxide containing from 1.2 to 2.6 moles of water of hydration, (2) a commercial activated alumina, (3) a commercial activated eta alumina and (4) a commercial activated alumina be lieved to be a gamma alumina, as supports for sulfided nickel-tungsten hydrogenating components, four separate hydrocracking runs were conducted. In every instance the hydrocracking of the above-described stock was conducted at 900 F., 500 psi. hydrogen partial pressure, an LHSV of 2.0 and a hydrogen circulation of 10,000 s.c.f./bbl. Prior to these hydrocracking runs the feed stock had been hydrodenitrogenized to a nitrogen content of less than one part per million. When employing catalyst (l), which had 7.8 percent of its pore volume in pores larger than 70 A. radius, a conversion of 70 percent to material boiling below 400 F. was obtained. When employing catalyst (2), having 11.9 percent of its pore volume in pores larger than 70 A. radius, a conversion of 67 percent to material boiling below 400 F. was obtained. When employing catalysts (3) and (4), however, having 24.9 and 31.7 percent, respectively, of their pore volumes in pores larger than 70 A. radius, conversions to material boiling below 400 F. of only 58 percent and 46 percent, respectively, were obtained. It will be seen, therefore, that catalysts having the pore size distribution required in the first stage of our process exhibit a marked superiority with respect to their ability to convert the charge stock to lower boiling materials.

When a catalyst containing a sulfided hydrogenating component is to be employed in the first stage of our process and such component is not initially deposited in sulfided form, the catalyst can then be treated with a sulfiding material such as hydrogen sulfide in order to form the metal sulfides. This is carried out advantageously by treating with a mixture of hydrogen and hydrogen sulfide containing up to about 20 percent hydrogen sulfide, at a temperature between about 400 and 900 F. It has also been found that especially advantageous results regarding conversion are obtained when sulfiding is combined with treatment at similar conditions with a mixture of hydrogen and ammonia in about the same proportions as the hydrogen sulfide. The combined pretreatment can he carried out simultaneously or in separate steps in either order, as preferred. This pretreating, whether conducted in single or consecutive steps, should be at temperatures not exceeding the on-stream temperatures to be employed in the first stage of our process and at a space velocity of about 500 to 5,000 volumes of gas per hour per volume of catalyst, for at least about half an hour up to several hours.

Although the first stage of our process can be conducted at a temperature anywhere in the range from about 750 to 1000 F., it is preferred to operate at the higher temperatures within this range in order to insure that the temperaure employed in the first stage is substantially higher than that employed in the second stage. Thus, we prefer to conduct our first stage hydrocracking at temperatures above about 800 F. Conversely We prefer to conduct the first stage of our process at the lower pressures within the range from about 250 to 750 p.s.i.g. Preferably, we operate the first stage of our process at the lowest pressure consistent with desired conversion thereby minimizing hydrogen consumption to the greatest extent. Thus, for example, conduct of the first stage of our process at pressures in the range from about 350 to about 600 p.s.i.g. is preferred. The space velocity employed in our first stage operation is also selected so as to be consistent with the goals of obtaining desired conversion with minimum hydrogen consumption. We prefer to employ a space velocity from about 1.0 to about 2.0.

It should also be pointed out here that both the quantity of hydrogen consumed, if any, and the quality of the product from the first stage boiling below 400 F. expressed in octane number is to a great extent determined by the particular feed stock selected for treatment. Thus, for example, the employment of a stock comprising as high as 70 to 80 percent aromatic constituents can produce a product having a research octane rating of as much as 4, 5 or even more numbers higher than that which can be obtained with a less aromatic stock. The presence of a substantial amount of constituents containing at least one saturated ring, for example, up to about 30 percent of the total components, will not only reduce hydrogen consumption to an extremely low level but will in many instances result in an over-all production of hydrogen in our first stage operation. An illustration of such a stock is a catalytically cracked furnace oil boiling, for example, in the range from about 400 to about 500 F. or 550 F. When a feed stock of this nature is treated in the first stage of our process, the first stage product boiling below 400 F. usually will be about 5 to 6 leaded research octane numbers higher than the product obtained with similar treatment of a full range catalytically cracked furnace oil. Also the particular operating conditions selected from the above ranges for treatment of a particular charge stock should be such that net conversion to products boiling below 400 F. is maintained in the range from about 30 to 60 percent by volume of the charge stock.

It will be found that the first stage hydrocracking operation in accordance with our invention results in an efiluent having an unusually high aromatic content and that the fraction boiling below 400 F. will have an eX- tremely high octane number, usually in the range of leaded research octane numbers higher than 95. As will be understood, the portion of the efliuent boiling above 400 P. will be comprised of a substantial quantity of polynuclear aromatic constituents which are highly refractory in nature. Such materials are unsuitable for recycle to the first stage of our process. Thus, in accordance with our invention, the 400 F.+ fraction from the first stage eflluent is passed to a second stage hydrocracking operation wherein it is contacted with hydrogen under the conditions set forth above, which conditions facilitate hydrocracking of the refractory polynuclear aromat cs without undue destruction of their cyclic nature.

The catalyst employed in this second stage operation of our invention can be any dual component hydrocracking catalyst comprising a hydrogenating component composited with an active cracking base. The hydrogenating components which can be employed include Group VI and VIII metals, and their oxides and sulfides. Thus, for example, nickel, cobalt, molybdenum, tungsten, and the oxides and sulfides thereof, either alone or in combination are satisfactory. The support for these hydrogenating components can be any of the catalytically active refractory metal oxides or combinations thereof, such as, for example, silica, alumina, titania, silica-alumina, silicamagnesia, etc. These catalyst composites can also be promoted with from about 0.5 to 5.0 percent by weight based on the total catalyst of a halogen. Particularly advantageous are fluorine and chlorine. Particularly suitable catalyst composites for employment in the second stage of our process include nickel-cobalt-molybdenum or sulfided nickel-tungsten supported on a silica-alumina carrier. These components can also advantageously be promoted with about 2 percent by weight of combined fluorine.

In this second stage hydrocracking operation of our process a temperature in the range from about 600 to about 800 F. should be employed. It is generally preferred, however, to employ an operating temperature somewhat below that employed in our first stage operation, such as, for example, below about 750 F. The pres sure employed in this second stage operation can be in the range from about 1000 to about 3000 p.s.i.g. and preferably is in the range from about 1500 to about 2500 p.s.i.g. The space velocity employed in the second stage hydrocracking of our process is generally more severe than that employed in the first stage and will usually be in the range from about 0.5 to about 2.0. The particular operating conditions employed should be selected from the above ranges in order to effect a hydrogen consumption of at least 1000 s.c.f.'/bbl. of 400 F.+ fraction charge and a conversion of at least per cent by volume to materials boiling below 400 F.

The advantages which can be obtained by operation in accordance with the process of our invention can be seen from the comparison of results shown below.

EXAMPLE I A pretreated light fluid catalytically cracked furnace oil distillate is hydrocracked in accordance with the techniques of conventional one-stage operation to produce a naphtha or gasoline fraction boiling in the range from C to 400 F. which has a leaded research octane number of about 91.5. Treatment of the same charge stock in accordance with the process of our invention results in a blended product obtained by combining the C to 400 F. fraction from both the first and second stages of our process which has a leaded research octane number of about 95.5. Thus, it will be seen that the process of our invention yields a product which is superior to that obtained by conventional techniques.

In order to dramatize the reduction in hydrogen consumption provided by our invention, a pretreated light fluid catalytically cracked furnace oil distillate was hydrocracked under the first stage conditions of our invention including a temperature of 850 F., a hydrogen partial pressure of 500 psi, a space velocity of 1.0 LHSV and a hydrogenzoil ratio of 10,000 s.c.f./bbl. of oil. The catalyst employed was a 6 percent nickel-19 percent tungsten on an activated alumina having 7.6 percent of its pore volume in pores larger than 70 A. radius, prepared by drying and calcining an aluminum hydroxide containing from 1.2 to 2.6'moles of water of hydration. The catalyst was pretreated at 700 F. and at 500 p.s.i.g. for three hours with a gaseous mixture containing 10 percent hydrogen sulfide, 2 percent ammonia and 88 percent hydrogen. The feed stock had the following properties. I 7

Feed stock (pretreated light FCC furnace oil),

The results of this first stage operation in accordance with our invention are shown in Table I below.

7 Table I Yields: percent by vol. of feed C -C (percent by wt.) 2.8 C 4.7 C; 5.5 C 400 F 42.0 400 F;+ 50.1 Hydrogen consumption: s.c.f./bbl. -210 Inspections of products- C 400 F. gasoline:

Gravity, API 50.0 Octane number Res., +3.0 cc. TEL 96.6 Motor, +3.0 cc. TEL 87.0 Aromatics 46.5 400 F.+:

Gravity, API 17.1 Aromatics, percent by vol 92.1 Nitrogen, p.p.m. 1 Sulfur, p.p.m. Olefins, percent by vol 0.9

From the above data it will be seen that this first stage operation of our process provided a conversion of about 50 percent by volume to materials boiling below 400 F. with a yield of 42 percent by volume of high octane gasoline having a leaded research octane number of 96.6. It will be further noticed that the normally refractory, high hydrogen consuming, aromatic feed was not only satisfactorily hydrocracked with an extremely low hydrogen consumption but that in fact such hydrocracking was efiected with a net hydrogen production of 210 standard cubic feet per barrel.

The 400 F.-+ fraction from this first stage operation and which contains more than 90 percent by volume aromatics is charged to the second stage hydrocracking operation of our invention employing a temperature substantially lower than that employed in the first stage and a pressure substantially higher than that employed in the first stage with an over-all consumption of hydrogen exceeding 1000 standard cubic feet per barrel of hydrocarbon charge in order to effect a conversion greater than 70 percent to materials boiling below 400 F. The C to 400 F. fraction obtained from the second stage afiluent is combined with the corresponding fraction from the first stage operation to provide a blended fraction having a leaded research octane number of 95.5. The net hydrogen consumption for the combined first and second stages of this operation is about 1050 standard cubic feet per barrel of light FCC furnace oil charged to the first stage.

In order to clearly indicate the net consumption of hydrogen required to produce a C to 400 F. fraction having a comparable octane number such fraction from a conventional one-stage hydro-cracking operation is reformed to increase its leaded research octane number from about 91.5 up to about 95.5. Combining the quantity of hydrogen consumed in the conventional hydrocracking operation and the over-all hydrogen produced in the reforming operation results in a figure of about 1750 standard cubic feet of hydrogen consumed per barrel of stock charged to the hydrocracking operation. It will be seen, therefore, that the process of our invention provides a product comparable in quality to that obtained in accordance with conventional techniques but with a reduced consumption ofhydrogen in the order of 700 standard cubic feet per barrel of charge stock.

EXAMPLE II A second example of advantages obtained through use of our invention is found in the hydrocracking of a full 'range pretreated fluid 'catalytically cracked furnace oil 8 Aromatics, percent by vol 51.6 ASTM distillation F;

Hydrocracking of this material in accordance with techniques of conventional, one-stage operation produces a naphtha or gasoline fraction boiling in the range from C to 400 R, which has a leaded research octane number of about 88.5. Hydrocracking the same charge stock in accordance with the process of our invention results in a blended product obtained by combining the C to 400 F. fraction from both first and second stage of our process which has a leaded research octane number of about 93.5. At the same time, hydrogen consumption for combined first and second stages of our process is about 900 standard cubic feet perbarrel less than for the conventional hydrocracking process. Thus, it can be seen that our invention not only yields a superior product but does so at a significantly lower hydrogen consumption.

EXAMPLE III To demonstrate further the superior results obtained in the practice of our invention over those obtainable with a two-stage process in which dehydrogenative conditions are employed in the first stage along with a conventional alumina base hydrocracking catalyst a comparison of the following results can be made. Two separate two-stage hydrocracking processes are operated employing substantially the same operating conditions in the first stages as well as in the second stages of both processes. In the first process a conventional alumina base hydrocracking catalyst is employed in the first stage while the second process is conducted in accordance with our invention employing the specific catalyst required in the first stage of our process. The eflluent from the first stage of the process employing the conventional alumina base catalyst comprises about 32 percent by volume of C to 400 F. gasoline having a leaded research octane number of about 90 to 95. On the other hand, the affluent from the first stage hydrocracking operation in accordance with our invention comprises about 40 percent by volume of a C to 400 F. gasoline having a leaded research octane number above about 96. The 400 F.+ fraction from the first stages of both processes are then subjected to conventional hydrocracking in a second stage employing a conventional silicaalumina base hydrocracking catalyst. The C to 400 F.

fraction from the second stage of each of the two processes is then blended with the cor-responding fraction from the first stage of the respective process. The leaded research octane number of the blend obtained from the first process employing a conventional alumina base catalyst in the first stage is still somewhat lower than the leaded research octane number of about which is obtained in accordance with the process of our invention. Although the hydrogen consumption rate of the two-stage process employing a conventional alumina base catalyst in the first stage is substantially lower than the 1750 standard cubic feet per barrel shown above for a conventional one-stage hydrocracking operation, the hydrogen consumption rate is still some 50 to standard cubic feet per barrel greater than the hydrogen consumption rate of 1050 standard feet per barrel obtained in the two-stage process of our invention. Thus, it can again be seen that the process of our invention generally provides a product of superior quality at a reduced rate of hydrogen consumption over that obtained by more conventional practice having a greater hydrogen consumption.

In addition to the advantages obtained in accordance with our invention and pointed out above, the practice of our inventive process requiring the employment of a particular type of alumina in the first stage eliminates the necessity of employing a conventional silica-alumina base hydrocracking catalyst in such first stage. The absence of a silica-alumina base catalyst permits conduct of the desired first stage reactions for an extended period of time and prevents an excessively high degree of cracking which in turn deleteriously effects catalyst life.

We claim:

1. A two-stage hydrocracking process which comprises hydrocracking in a first stage a hydrocarbon stock boiling in the range from about 400 to about 850 F., containing less than about ppm. nitrogen, containing up to about 80 percent by volume of aromatic hydrocarbons and containing at least 30 percent by volume of hydrocarbons having at least one saturated ring by contacting the hydrocarbon stock with hydrogen at a temperature in the range from about 800 to about 1000 F., a pressure in the range from about 350 to about 650 p.s.i.g., a space velocity in the range from about 1.0 to about 2.0 volumes of hydrocarbon stock per hour per volume of catalyst, with a hydrogen consumption of less than 200 standard cubic feet of hydrogen per barrel of hydrocarbon stock while in the presence of a catalyst comprising a hydrogenation component consisting essentially of sulfided nickel-tungsten wherein the tungsten comprises from about 3 to about 25 percent by weight of the total catalyst and the nickel comprises from about 0.5 to about percent by weight of the total catalyst, composited with an activated alumina having less than about 10 percent of its pore volume in pores having a radius greater than 70 A., thereby effecting a conversion from about 30 to about 60 percent by volume to materials boiling below the initial boiling point of the hydrocarbon charge stock, separating from the eflluent of the first stage a gasoline fraction boiling up to 400 F. and a fraction boiling above 400 F., hydrocracking the fraction boiling above 400 F. in a second stage by contacting said 400 F.+ fraction with hydrogen at a temperature in the range from about 600 to about 750 F., a pressure in the range from about 1500 to about 2500 p.s.i.g., a space velocity in the range from about 0.5 to about 2.0 volumes of 400 F.+ fraction per hour per volume of catalyst, with a hydrogen consumption of at least 1,000 standard cubic feet of hydrogen per barrel of 400 F.+ fraction while in the presence of a dual component hydrocracking catalyst consisting essentially of a hydrogenation component selected from the group consisting of Group VI and VIII metals, their oxides and sulfides, supported on a refractory metal oxide carrier having substantial cracking activity, thereby eITecting a conversion of a least percent by volume to materials boiling below 400 F. and separating from the efiluent from the second stage a second gasoline fraction boiling up to 400 F.

2. The process of claim 1 wherein the catalysts contain from about 0.5 to about 5.0 percent by weight of a halogen.

3. The process of claim 1 wherein there is a net production of hydrogen in the first stage thereof.

References Cited UNITED STATES PATENTS 5/1965 Kozlowski et al 208111 5/1965 Flinn et a1 208-112 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,360,456 December 26, 1967 Joseph K. Kosiba et al.

pears in the above numbered pat- It is hereby certified that error ap nt should read as ent requiring correction and that the said Letters Pate corrected below.

Column 1, line 38, for "difficulty" read difficultly column 7, line 44, for "affluent" read effluent column 8, line 3, for "545" read 454 line 41, for "affluent" read effluent Signed and sealed this 21st day of January 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

Claims

1. A TWO-STAGE HYDROCRACKING PROCESS WHICH COMPRISES HYDROCRACKING IN A FIRST STAGE A HYDROCARBON STOCK BOILING IN THE RANGE FROM ABOUT 400* TO ABOUT 850*F., CONTAINING LESS THAN ABOUT 5 P.P.M. NITROGN, CONTAINING UP TO ABOUT 80 PERCENT BY VOLUME OF AROMATIC HYDROCARBONS AND CONTAINING AT LEAST 30 PERCENT BY VOLUME OF HYDROCARBONS HAVING AT LEAST ONE SATURATED RING BY CONTACTING THE HYDROCARBON STOCK WITH HYDROGEN AT A TEMPERATURE IN THE RANGE FROM ABOUT 800* TO ABOUT 1000*F., A PRESSURE IN THE RANGE FROM ABOUT 350 TO ABOUT 650 P.S.I.G., A SPACE VELOCITY IN THE RANGE FROM ABOUT 1.0 TO ABOUT 2.0 VOLUMES OF HYDROCARBON STOCK PER HOUR PER VOLUME OF CATALYST, WITH A HYDROGEN CONSUMPTION OF LESS THAN 200 STANDARD CUBIC FEET OF HYROGEN PER BARREL OF HYDROCARBON STOCK WHILE IN THE PRESENCE OF A CATALYST COMPRISING A HYDROGENATION COMPONENT CONSISTING ESSENTIALLY OF SULFIDED NICKEL-TUNGSTEN WHEREIN THE TUNGSTEN COMPRISES FROM ABOUT 3 TO ABOUT 25 PERCENT BY WEIGHT OF THE TOTAL CATALYST AND THE NICKEL COMPRISES FROM ABOUT 0.5 TO ABOUT 10 PERCENT BY WEIGHT OF THE TOTAL CATALYST, COMPOSITED WITH AN ACTIVATED ALUMINA HAVING LESS THAN ABOUT 10 PERCENT OF ITS PORE VOLUME IN PORES HAVING A RADIUS GREATER THAN 70 A., THEREBY EFFECTING A CONVERSION FROM ABOUT 30 TO ABOUT 60 PERCENT BY VOLUME TO MATERIALS BOILING BELOW THE INITIAL BOILING POINT OF THE HYDROCARBON CHARGE STOCK, SEPARATING FROM THE EFFLUENT OF THE FIRST STAGE A GASOLINE FRACTION BOILING UP TO 400*F. AND A FRACTION BOILING ABOVE 400*F., HYDROCRACKING THE FRACTION BOILING ABOVE 400*F. IN A SECOND STAGE BY CONTACTING SAID 400*F.+ FRACTION WITH HYDROGEN AT A TEMPERATURE IN THE RANGE FROM ABOUT 600* TO ABOUT 750*F., A PRESSURE IN THE RANGE FROM ABOUT 1500 TO ABOUT 2500 P.S.I.G., A SPACE VELOCITY IN THE RANGE FROM ABOUT 0.5 TO ABOUT 2.0 VOLUMES OF 400*F.+ FRACTION PER HOUR PER VOLUME OF CATALYST, WITH A HYDROGEN CONSUMPTION OF AT LEAST 1,000 STANDARD CUBIC FEET OF HYDROGEN PER BARREL OF 400*F.+ FRACTION WHILE IN THE PRESENCE OF A DUAL COMPONENT HYDROCRACKING CATALYST CONSISTING ESSENTIALLY OF A HYDROGENATION COMPONENT SELECTED FROM THE GROUP CONSISTING OF GROUP VI AND VIII METALS, THEIR OXIDES AND SULFIDES, SUPPORTED ON A REFRACTORY METAL OXIDE CARRIER HAVING SUBSTANTIAL CRACKING ACTIVITY, THEREBY EFFECTING A CONVERSION OF AT LEAST 70 PERCENT BY VOLUME TO MATERIALS BOILING BELOW 400*F. AND SEPARATING FROM THE EFFLUENT FROM THE SECOND STAGE A SECOND GASOLINE FRACTION BOILING UP TO 400*F.