US3281350A - Hf deasphalting for hydrocracking feed preparation - Google Patents

Description

Ot. 25, 1966 H. G. GODET ETAL HF DEASPHALTING FOR HYDROCRACKING FEED PREPARATION Filed May 6, 1963 United States Patent O HF DEASPHALTING FOR HYDROCRACKING FEED PREPARATION Howard G. Codet, Westfield, and John W. Herrmann, Mountainside, NJ., assignors to Esso Research and Engineering Company, a corporation of Delaware Filed May 6, 1963, Ser. No. 278,086 8 Claims. (Cl. 208-62) The present invention relates to the conversion of hydrocarbons and more particularly t-o a highly integrated process in which hydrogen fluoride deasphalting and demetalization of the higher boiling hydrocarbons is utilized t-o obtain treated hydrocarbons from which a hydrocracking feed, a reformer feed and a Ithermal cracking feed, which is used to make hydrogen and a high value coke, are obtained.

It has long been recognized that hydrocarbon fractions, such as crude petroleum oil, atmospheric residuum or vacuum bottoms normally contain iron, nickel, vanadium and other metallic contaminants which have an adverse effect upon various catalysts employed in the petroleum processing operations and upon combustion equipment in which such petroleum fractions are burned as fuels. Furthermore, these metallic contaminants or substances poison catalysts used in operations such as hydroforming and hydrocracking. In the high boiling fraction or residual type fuels such contaminants attack the refractories used to line boilers and combustion chambers, cause clogging and the buildup of deposits upon boiler tubes and severely corrode metallic surfaces with which they come into contact.

Further well-known difficulties have been caused by the presence of asphaltenes and asphaltic substances which con-tain compounds of sulfur and nitrogen. Gasoline must be relatively sulfur free in order to make it compatible with lead. Motor fuels containing sulfur as mercaptans are undesirable because of odor and gum formation characteristics. Sulfur is particularly objectionable in fuel oils because it burns to form SO2 which is a highly corrosive and foul-smelling compound. As for nitrogen, this element, even in relatively slight amounts, can have disastrous effects on catalytic activity within the refinery process, particularly with cracking catalysts. In addition the asphaltenes and asphaltic substances themselves yield large quantities of coke upon cracking, as evidenced by their high Conradson carbon content.

In prior processes, a separate hydrofning step was needed before reforming or hydrocracking to remove nitrogen, sulfur and other contaminating materials. Hydrofining 4was also needed -to improve odor, appearance and stability of various products. However, although the results of this process are quite satisfactory, there .is considerable expense involved. It is, therefore, desirable to find a method in which this step may be eliminated and yet produce feed stocks which will have all desired characteristics.

It should also be noted that an inferior grade coke is often a by product of refinery operations. This coke with its high metals and contaminant content must be either sold at a low price for use as fuel or further processed, at considerable expense, to make it acceptable for other uses such as metallurgical or electrode coke.

These problems and various others are successfully solved by the present invention. According to this invention, an oil such as a preflashed crude, atmospheric residuum or vacuum bottoms (after being diluted with propane) is treated with hydrogen fluoride (HF) in either aqueous or anhydrous form, thereby precipitating a solidmetals complex and forming a raliinate and an extract. The Conradson carbon, aromatics, sulfur and nitrogen are 3,281,350 Patented Oct. 25, 1966 concentrated in the extract fraction. This extract amounts to about 15-25% of the oil feed. The extract, after removal of the HF, is made substantially metal-free by filtering out the precipitated solid-metals complex. After this, the filtered extract is -ther-mally cracked to produce hydrogen and a premium-value, metals free coke. The hydrogen is passed into a hydrocracker.

The raffinate, or petroleum fraction which has been separated from the extract, is stripped of HF and filtered and then directed to a fractionating tower. Here the raffinate is fractionated and a plurality of streams recovered. The lightest fraction is sent directly to a hydroformer. The middle fraction is withdrawn from the system and may be utilized as diesel fuel, jet fuel or heating oil component. The bottom fraction is passed into the hydrocracker int-o w-hich the hydrogen from the thermal cracker was passed. This hydrogen, along with the hydrogen produced in the hydroformer operation, provide sufficient hydrogen for the hydrocracking operation. After -hydrocracking, the hydrocracked naphtha is divided into two parts; a heavier part going to the hydroformer, along with the lightest virgin cut from the fractionating tower, and a lighter fraction which is used directly as a gasoline blending component. The hydroformed naphtha is recovered and provides a highly desirable motor fuel. It should be noted that no hydrofining operation is needed to remove impurities from either the hydrocracker or reformer feeds.

The figure diagrammatically represents one form of apparatus adapted to practice the present invention.

In the drawing, the reference character 10 designates a line through which a crude petroleum oil to be treated is passed into preashing vessel 11. A lighter fraction, boiling below about 200 F., is drawn off overhead through line 12; this fraction usually represents less than 10% of the entire oil feed. Usually over 90% of the crude oil feed, boiling above about 200 F., is removed from vessel 11 through line 13 and is passed into a combined deasphalting and demetalization or extraction zone or tower 14. An aqueous solution of or anhydrous HF in the amount of 0.1 to 1.0 weight of HF per Weight of oil is directed into the zone `through line'15. In this extraction zone 14 the crude oil and HF acid are contacted by mixing or by agitation for a period of 1-90 minutes at a temperature of 200-350 F. in order `to convert the metals to an insoluble inorganic fluoride complex. At the same time, the HF-oil mixture separates into a raffinate phase and an extract phase.

A bottom stream of extract phase from extraction zone 14 amounting to l0-20% of the total crude and containing most of the HF, feed Conradson carbon components, polynuclear aromatic, nitrogen and sulfur compounds and the precipitated metals complex is withdrawn through line 16 to a stripper tower 17 where HF is recovered and recycled back to the extraction zone 14 through line 18. Stripping gas, such as butane, may be introduced into `stripper 17 through line 17. Stripper 17 is maintained at a temperature of 200 to 300 F. The HF free extract is fed from the stripper zone 17 through line 18' to a filter 19 and the solid metals complex removed through line 20. This complex is only a fraction of a percent of the total crude. The filter may be any conventional filter such as `a simple sand filter, a rotary filter, or a Dorr settler. Subsequent to filtration, the extract from which the solidrnetals complex has been removed is introduced into thermal cracking or high temperature coking zone 21 to produce coke and hydrogen.

This thermal cracking zone consists of a reactor containing a fiuidized bed of coke and operating at about 1700-2600 F. and 0-100 p.s.i.g. to produce hydrogen and coke. Temperature is maintained by burning natural gas in a transfer line burner through which part of the coke is circulated, by electrical resistance heating within.

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o the Huid bed itself or other suitable means of heat supply. In this manner, a virtually metal-free coke is produced and withdrawn through line V22. Simultaneously, hydrogen is recovered from the thermal cracker 21 overhead and passed to hydrocracker 23 through line 24.

The overhead stream from demetalization and deasphalting zone 14 includes raffinate amounting to 80-90% of the crude as well as some HF and solid metals complex. The stream is withdrawn through line 25 and passed to stripper tower 26. Stripping tower 26 is maintained at a temperature of 200 to 300 F. Stripping gas may be introduced into the tower through line 26 is desired.

In stripper tower 26 HF is taken overhead through line 27 and passed into line 18. The HF passes through line 18 into deasphalting zone 14. Deasphalted oil is removed as a bottoms stream from stripper 26 through line 28 to filter 29 where the remaining solid metals complex is removed. The demetalized raffinate is passed through line 30 into atmospheric tower 31 from whence three streams are withdrawn.

A light fraction, boiling between about ZOO-375 F. and consisting of approximately -15% of the volume of the crude oil feed is drawn off through line 32 and passed to hydroformer 33. An intermediate fraction boiling between about 375 and 430 F. is drawn off through line 34 and may be utilized for any suitable purpose such as heating oil, diesel fuel or jet fuel; this would consist of approximately 0-10% of the volume of the crude oil feed. Finally, a bottoms fraction consisting of 60-70% of the crude oil feed, and boiling above 430 F., is removed through line 35 and sent directly to hydrocracker 23. The hydrocracker feed is heated in any conventional manner to about 500 to 750 F. by means not shown.

Hydrocracker 23 may be of the fluid catalyst variety but it is preferred to use a fixed bed catalyst hydrocracking zone. It is preferred to use a bifunctional sieve-based catalyst such as palladium on a crystalline zeolitic metal alumino-silicate molecular sieve having uniform pore openings between about 6 and 15 A. units or palladium on a decationized crystalline zeolitic metal alumino-silicate molecular sieve having uniform pore openings between about 6 and 15 A. The molecular sieve is further characterized in that it contains no more than about sodium calculated as NaZO, preferably between about 0.5 and 8.5%

The molecular sieves are crystalline zeolitic aluminosilicates that are characterized by having pores of a uniform diameter. They may be either a natural zeolite such as Faujasite or they may be synthetic zeolites such as the 13X or 13Y molecular sieves. The ammonium sieve may be impregnated with palladium by treatment with a solution of palladium chloride. The palladium impregnated ammonium sieve is converted to the active catalyst by heating to a temperature in the range of 600-1000 F. to drive olf the ammonia and reduce the palladium to a zero valence state. The amount of the palladium in the catalyst is between 0.01 and 5.0 wt. percent.

Other bifunctional catalysts may be used which may consist of a conventional cracking component plus a minor proportion of a heavy metal -oxide or sulde which is effective in the promotion of hydrogenation reactions. Such catalysts may comprise for example between about 1% and 10% by weight of the oxides or sulfides of the transitional metals, particularly those of Groups VB, VIB, VIIB :and VIII, or mixtures thereof. Particularly desirable components consist of the oxides or sulfides of chromium, molybdenum, tungsten, iron, cobalt, nickel, or the metals platinum, or palladium. The carrier on which these materials are deposited may consist for example of synthetic coprecipitated silica-alumina, silica-zirconia, silica-titania, silica-titania-zirconia, silica-magnesia, and the like. Acid-activated montmorillonite clays may also be employed. Any of these carriers may be further activated by the incorporation of small amounts of acidic materials such as uorine or chlorine.

The alternate catalysts for the hydrocracking reaction may consist of a coprecipitated base composed of l0 to 65% silica, 15 to 65 titania, and 15 to 65 zirconia, on which is deposited as by impregnation or coprecipitation a minor amount, from about 0.5% to about 7%, of a promoter, e.g. an oxide of chromium, molybdenum, tungsten, cobalt, nickel, or any combination thereof. Alternatively, even smaller proportions, between about 0.05% and 1.0% of the metals platinum or palladium may be employed. The oxides and sulfides or other transitional metals may also be used, but to less advantage than the foregoing.

Operative conditions in the hydrocarcking zone depend upon feedstock quality and the degree of conversion required. Hydrocracking temperatures (average bed) may -suitably range between about 500 and 1000 F., and preferably lbetween about 550 and 800 F.

Pressures in the hydrocracking zone may range between about 500 an-d 3,000 p.s.i.g., and preferably between about 800 and 2,500 p.s.i.g. The liquid hourly space velocity may range between about 0.5 and 4 volumes of liquid feed per volume of catalyst per hour.

Since the process is exothermic, provision must be made for removing heat from the system. The preferred method is to inject streams of cool hydrogen-rich gas at intermediate points along the length of the lfixed bed of catalyst. In addition to this cooling gas and the makeup hydrogen which is consumed in the process, a stream of hydrogen-rich gas amounting to G-15,000 s.c.f./b. of feed, and preferably -between about 2,000 and 10,000 s.c.f./b. of feed is injected at the inlet to the reactor.

Conversion of feed to lighter material is high and unconverted material may be separated from product and recycled to the reactor. Hydrogen consumption depends on feedstock quality and degree iof conversion. For typical feeds at total conversion to gasoline, hydrogen consumption ranges between 1600 and 2500 s.c.f./b. feed.

There is virtually no coke make in the process and, therefore, catalyst regeneration is needed very seldom, if ever.

After the hydrocracking is complete, the hydrocracked product is removed and passed through line 23 into fractionator 24. Here the hydrocracked product is divided into a .plurality of streams. A C4- fraction is removed through line 36 and sent to light ends recovery. A C5/180 fraction is removed through line 37 and goes directly to motor gasoline. A hydrocracked naphtha boiling between ISO-430 F., amounting to between 50 and 60% of the crude oil feed, is withdrawn through line 38 and is admixed with the 20G-375 F. fraction which was withdrawn through line 32 from tower 31. A heavier 430+ fraction is recovered through line 39 and recycled to hydrocracker 23.

The combined `streams from lines 32 and 38 are passed through line 40 into hydi'oformer 33. Within hydroformer 33 the hydrocarbons are transformed from low grade fuels into high octane motor fuels. Hydroformer 33 may be either of two types, semiregenerative which, as the name connotes, would require relatively infrequent catalytic regeneration, or cyclic hydroforming which includes frequent regeneration.

The hydroforming zone 33 preferably contains a fixed bed of catalyst employing a platinum on alumina catalyst. Turning first to the semiregenerative form, the catalyst may contain between about 0.01 and 5.0 wt. percent of platinum on alumina containing between about 0.0 and 5.0 wt. percent of silica. The pressure in zone 33 is maintained at 400-750 p.s.i.g. and preferably 400-500 p.s.i.g. The inlet temperature is maintained at 925-1000 F. The recycle gas rate which is primarily hydrogen is maintained within a range of Z500-10,000 s.c.f./b. of oil feed. Catalyst requirement is based` on a feed rate of 1.5 to 2.5 pounds of feed per hour per pound of catalyst. Lower temperatures are yused at the start of the operation and the temperature is increased accordingly as coke deposits form on the catalyst and serve to deactivate it.

The cyclic hydroformer is similar to the semi-regenerative one, except that it does provide for an extra reactor so that one reactor can be regenerated without a stoppage of operations. The hydroformate and hydrogen are passed along line 41 to products recovery zone 42. The reforming process also makes hydrogen as a by-prod'uct and, as mentioned earlier, part of the hydrogen recycle representing the net hydrogen make is passed through line 43 and together with the hydrogen coming from the thermal cracker 21 is passed through line 24 to hydrocracker 23.

A high octane reformate is recovered through line 44 which represents 60-75% of the crude introduced by means of line 10.

Bottoms are removed throu-gh line 42'.

It is readily seen by one skilled in the art that the previously-described HF treating process may be utilized for an atmospheric or vacuum bottoms, although the latter may require the addition of a -suitable diluent such as propane or butane to increase ease of handling.

Typical data for deasphalting and demetalization of heavy oils are indicated in the following table:

6 subjected to a temperature of 2200 F. and a pressure of 50 p.s.i.g. for a period of 10 seconds or less. A virtually metal-free premium valued coke is produced and withdrawn from zone 21 through line 22; the coke amounts to about 600 t./d.

Simultaneously with the coke production, 29.7 mm. s.c.f./d. of hydrogen are manufactured. This hydrogen is di-rected to hydrocracker 23 through line 24.

The remaining 25,900 barrels of oil which comprise the railinate from tower 14 are directed overhead through line to stripper 26. It should be noted that a small amount of HF is included as well as about 10% of the solid metals complex. The HF is removed from the stripper 26 and through line 27 and passed into line 18 from whence it is passed to deasphalting tower 14. The raflnate with included solid metals complex is withdrawn through line 28. It is passed through sand lter 29, the solid and metals are removed. The ralinate is then passed through line into atmospheric tower 31. Here the raffinate is fractionated at atmospheric pressure. About 3200 barrels of oil boiling between 200-375 F. are drawn off through line 32 and sent to hydroformer Table I Feed 250L1 F. -i-Crude Atm. Resid. 600 Vae. Resid. 950

HF Deasphalting Conditions:

HF, Wt. per Wt. Oil 0. 5 1.0 0. 5 Butane Diluent Vol. per Vol. Oil Feed None None 6 Extraction Temperature, F 100 200 200 Feed Rainate Feed Rarinate Feed Raiinate Oil Yield:

Wt. percent on Feed 100 80 100 74 100 73 Vol. percent on Feed 100 82 100 76 100 76, 5 Inspections:

Gravity, API 28. 6 32A 0 19. 5 23.7 1i. o 19. 2 Conradson Carbon, Wt 2. 4 0. 6 5. 5 1. 8 15. 0 4. 6 Sulfur, Wt. pcrcent 1. 4 0. 64 2. 2 1.0 3. 3 0.9 Nitrogen, Wt percen 0.12 0.01 0.24 0,04 0,43 0 15 N1clrel,p.p.m 5 0.5 12 1.0 25 0.5 Vanadium, p.p.m 8 0. 0 24 0 39 0 Thus the foregoing table shows that the raffinate is 33. About 1300 barrels are withdrawn through line 34 greatly improved over the eed in concentrations of contaminants such as Conradson carbon, sulfur, nitrogen, nickel and vanadium.

In addition to -this improved `feed for hydrocracking, a virtually metal-free coke is obtained from thermally cracking the iiltered extract. Furthermore, no hydroning step is needed for either the feed which is hydrolined or the feed which is hydrocracked.

In a specific example, about 30,000 barrels of crude petroleum oil are fractionated or preashed in tower 11. About 2100 barrels of hydrocarbon oil boiling -below 200 F. are removed through line 12. The remainder of the oil is withdrawn -from the bottom of tower 11 and passed through line 13 into demetalization and deasphalting zone 14. About 12,000 barrels `a day of anhydrous hydrogen fluoride (HF) are added to zone 14 through line 15. HF and oil are contacted at about 300 F. for about 10 minutes in an extraction tower where the metal contaminants are converted to insoluble, inorganic fluorides amounting to less than l wt. percent of the freed. At the same time, the HF-oil mixture separates into a rafnate and an extract fraction. The extract stream containing 4100 b./d. oil, also contains most of the sulfur, nitrogen and Conradson carbon containing compounds as Well as the HF and metals complex. This is drawn off the bottom of the tower 14 through line 16 to a stripper tower 17, where HF is lrecoVe-red and recycled back to the deasphalting zone 14 through line 18. The HF-free extract is -fed from the stripper tower 17 to a sand lter 19 through line 18. The solid metals complex is removed through line 20. The iiltered extract is removed from the lter through line 19 and introduced into thermal cracking unit 21. Thermal cracking unit 21 is of the fluidized bed variety. Here the extract is and used as heating oil. This fraction boils between 375-430 F. The bottoms fractions, boiling above 430 F and comprising about 19,300 barrels, is passed through line 35 to hyd-rocracker 23. The hydrocracker is of the fixed bed variety and is substantially similar in all details, including catalyst, to the one described previously. The catalyst consists of palladium on la. decationized crystalline zeolitic metal alurnino-silicate molecular sieve having uniform pore openings of about 13 A. The molecular sieve contains about 6% sodium calculated as NaZO. The hydrocracking is carried out at a temperature of about 650 F. and a .pressure of about 1500 p.s.i.g. Hydrogen in the amount of 45.6 mm. s.c.f./d. is needed.

The hydrocracked product amounting to about 21,300 barrels per day is removed through line 23' and passed into fractionator 24. About 16,000 barrels of 180-430 F. naphtha per day are Withdrawn through line 38, and together with the 3200 barrels per day from line 32 are passed to hydroformer 33. About 5300 barrels per day of C5/ 180 naphtha are withdrawn through line 37 and utilized directly as a gasoline. About 6.75 mm. s.c.f. of C4- components are withdrawn through line 36 and directed to light ends recovery.

Hydroformer 33 is of the cyclic variety. It is operated at a pressure of 250 p.s.i.g. and has a reactor temperature of 975 F. The recycle gas rate is 5000 s.c.f./b. and the catalyst requirement is based on 3 pounds of feed/ hour/pound of catalyst. About 15.9 mm. s.c.f./d. of hydrogen are channeled from the hydroformer 33 into products recovery zone 42 and then through lines 43 and 24 into hydrocracker 23. About 16,700 barrels per day of high grade gasoline are recovered through line 44. This gasoline has an octane number of about 98 Research, clear.

In the specific example given above, the thermal cracking step and the hydroformer produce all the hydrogen needed for the hydrocracker and hydroformer and no external hydrogen is added.

A conventional refining scheme to produce the required quantity and quality of products would include coking of atmospheric residuum to convert it to lighter products and help to prepare it for 4further processing by partial removal of Conradson carbon, sulfur, and nitrogen. The conventional refining scheme operates as follows: Preflashed crude is -fed to an atmospheric pipestill Ifor fractionation into several streams. The heaviest portion, 750 F.-{ atmospheric bottoms, is fed to a coker where it is converted into naphtha, gas oil, coke, and fuel gas. The coke from this unit contains a high proportion of the metal contaminants from the crude oil. This makes it a low valued product that must be burned as fuel or processed at considerable expense to make it suitable for more attractive outlets such as electrode coke. The coker gas oil boiling 4between about 430 F. and 850 F. is combined with the virgin gas oil boiling between about 430 F. and 750 F. from the atmospheric tower and the combination is sent to a two-stage hydrocracking unit. The first stage of this hydrocracking unit is primarily a hydrofiner to remove nitrogen from the feed and make it satisfactory for the second stage where the major part of the hydrocracking takes place.

The heavy naphtha product from the hydrocracker boiling between about 180 F. and 430 F. is combined with virgin naphtha from the atmospheric tower and is sent to a naphtha reformer. At least the virgin naphtha portion of this feed must first be hydrofined to remove sulfur and thus make it suitable for reforming. Hydrogen produced in -the reformer is used to meet part of the hydrocracker hydrogen requirements. To complete the hydrogen requirements, methane is steam reformed in a conventional hydrogen manufacturing unit.

The gasoline from this refinery is made up of light naphtha from the hydrocracker, reformer product, coker naphtha, butane, and suitable additives.

The HF deasphalting scheme, which is the subject of the present invention, has a number of significant economic advantages over the conventional refinery described above. These can be illustrated most easily'by referring to the attached Table 2 which represents operation of a 30,000 b./d. plant.

Although both refineries require equal quantities of crude to make essentially equal quantities of desired products, the improved case of the present invention saves 15,000,000 s.c.f./d. of methane needed in the conventional case for hydrogen manufacture. Also, because of the better quality of the naphtha components in the improved case, much less tetraethyl lead is needed to make the same quality finished gasoline in each case. This better naphtha quality results from the absence of low grade coker naphtha.

With -regard :to equipment requirements, the improved refinery requires no conventional coker, no hydrocracker feed hydrofining unit, no reformer feed hydrofiner, and a smaller atmospheric tower than the conventional case. These result in much greater savings than the cost of the Irequired deasphalting unit.

Although both refineries make `about the same quantity of gasoline, by-products from the improved case are significantly more valuable. This is especially true of the coke yield, which is only worth fuel value in the con- -ventional case because it is highly contaminated with undesirable metals. On the other hand, improved refinery coke product of the present invention is virtually metals free and therefore commands a premium price as electrode coke or for other specialty uses. In addition, there is a higher yield of this valuable coke since none of it needs to be burned for fuel. The improved refinery also makes less low-value fuel gas and more high-value propane and butanes, which can be used for such things as liquefied petroleum gas and gasoline components. For these reasons, the improved processing scheme represents a much more economically attractive refinery.

Atmospheric tower Fluid Coker H/F Deasphalting Unit Hydrofiner for reformer feed.

Hydrofmer for hydrocracker feed.- Products:

a. C4, net, b./d Fuel value Coke, t, Premium value coke, Finished Mogas, b./d

1 To make constant quality motor gasoline pool.

Table 2 illustrates some of the advantages of the instant case. It should be noted that considerably less TEL is needed to make a gasoline of instant quality. Additionally, as would be expected the need for methane as a source of hydrogen is eliminated. Considerably more coke is produced and it is of a premium quality.

What is claimed is:

1. In -a process for the preparation of a hydrocracking feed and production of a high value coke, the steps which comprise preiiashing a crude oil, thereby obtaining a lighter fraction boiling below about 200 F. and a heavier fraction boiling above about 200 F., recovering the said lighter fraction, passing said heavier fraction into a deasphalting and demetalization zone, passing HF into said zone for contacting said heavier fraction and in a sufficient amount to precipitate substantially all metals from said heavier fraction and to form an extract phase which amounts to about l0-20% of said crude oil feed in which are concentrated the compounds containing sulfur, nitrogen and Conradson carbon and a separate raffinate phase which amounts to about -90% of said crude oil feed, said precipitate being collected primarily in said extract phase, separating said extract phase and said raffinate phase, removing said extract phase from the said de- ,asphalting zone, filtering said extract phase to remove said precipitate containing heavy metal contaminants, passing the filtered extract phase into a high temperature thermal cracking zone, cracking the said metal-free extract substantially completely to metal-free coke and hydrogen, recovering said coke as a premium llow meta-ls coke, passing at least part of the said hydrogen into a vhydrocracking zone, fractionating said rafiinate phase into three streams, including (l) a lighter boiling stream Iwhich is passed without hydrofining to a hydroforming zone where it is hydroformed in the presence of hydrogen gas, recycling part of said hydrogen gas from said hydroforming zone to said hydrocracking zone, (2) an intermediate stream which is removed from the system as product, and (3) -a bottoms stream which is passed without hydrofining into -the said hydrocracking zone containing a catalyst comprising palladium on an aluminum silicate molecular sieve where it is hydrocracked in the presence of the 4recycle hydrogen from the said hydroforming zone and hydrogen from said thermal cracking step, recovering a low `boiling hydrocrackate naphtha-fraction which is re- `moved from the system and a higher boiling hydrocrackate naphtha fraction which is passed to the said hydroforming zone, and recovering ya high quality fuel from the said hydroforming zone.

2. The process of claim ll Where the said HF and said heavier fraction are contacted for a period of 1 to 60 minutes.

3. The proces-s of claim 1 Where the said lter is a sand filter.

4. The process of claim 1 where the said HF is an aqueous solution.

5. The process of claim 1 where the said three streams into which the ranate is fractionated are a ZOO/375 F. lighter fraction, a EWS/430 F. middle fraction and a 430 E+ bottoms fraction.

6. In a process for the preparation of a hydrocracking feed and the production of a high value coke, the steps which comprise passing a liquid hydrocarbon boiling above about 200 F. into a deasphalting and demetalization Zone, passing HF into said zone and contacting the said HF and said hydrocarbon for a period of 1-90 minutes thereby precipitating substantially all the metals from the said hydrocarbon and forming an extract phase which amounts to about %-20% of said liquid hydrocarbon feed in which are concentrated .the compounds containing sulfur, nitrogen and Conradson carbon and a raffinate phase which amounts to about 80-90% of said liquid hydrocarbon feed, said precipitate being collected in said extract phase, leaving a virtually metal-free raffinate phase, separating said extract phase and the said rainate phase, removing the said extract phase from the said deasphalting zone, filtering said extract phase to remove precipitate containing heavy metal contaminants, passing (the filtered extract phase into a thermal cracking zone, said zone being maintained at a temperature of 1800- 2600 F., whereby the said metal-free extract is cracked substantially completely to a metal-free coke and hydrogen, passing at least part of the said hydrogen into a hydrocracking zone, recovering said metal-free coke as product, fractionating the said raffinate phase into a plurality of streams including (1) a lighter boiling stream which is passed to the said hydroforming zone where it is hydroformed in the presence of hydrogen gas, recycling at least a part of said hydrogen gas from said hydroforrning Zone to the said hydrocracking zone, (2) an intermediate stream which is removed from the system and (3) a bottoms stream which is passed into the said hydrocracking zone where it is hydrocracked in the presence of the recycle hydrogen from the said hydroforming zone and hydrogen from said thermal cracking step, recovering a low boiling hydrocrackate fraction which is removed from the system and a higher boiling naphtha fraction which is passed to the said hydroforming zone, and recovering a high quality mot-or fuel from said hydroforming Zone.

7. The process of claim 6 Where the said liquid hydrocarbon is a 950 F.-|- vacuum resid. which has been diluted `with 1 to 6 volumes of a C3 to C5 hydrocarbon diluent per volume of oil feed.

8. The process of claim 6 wherein the said liquid hydrocarbon is a 950 F.|- vacuum resid. which has been diluted with a hydrocarbon selected from the group consisting of propane, butane and pentane.

References Cited by the Examiner UNITED STATES PATENTS 2,643,971 6/1953 Lien et al 208-86 2,727,853 12/1955 Hennig 208-86 2,971,905 2/1961 Bieber et al. 208-252 2,973,313 2/1961 Pevere et al. 208-86 3,061,539 1-0/1962 Moritz et al. 208-90 DELBERT E. GANTZ, Primary Examiner.

I. R. LIBERMAN, Examiner.

H. LEVINE, Assistant Examiner.

Claims (1)

1. IN A PROCESS FOR THE PREPARATION OF A HYDROCRACKING FEED AND PRODUCTION OF A HIGH VALUE COKE, THE STEPS WHICH COMPRISE PREFLASHING A CRUDE OIL, THEREBY OBTAINING A LIGHTER FRACTION BOILING BELOW ABOUT 200*F. AND A HEAVIER FRACTION BOILING ABOVE ABOUT 200*F., RECOVERING THE SAID LIGHTER FRACTION, PASSING SAID HEAVIER FRACTION INTO A DEASPHALTING AND DEMETALIZIATION ZONE PASSING HF INTO SAID ZONE FOR CONTACTING SAID HEAVIER FRACTION AND IN A SUFFICIENT AMOUNT TO PRECIPITATE SUBSTANTIALLY ALL METAL FROM SAID HEAVIER FRACTION AND TO FORM AND EXTRACT PHASE WHICH AMOUNTS TO ABOUT 10-20% OF SAID CRUDE OIL FEED IN WHICH ARE CONCENTRATED THE COMPOUNDS CONTAINING SULFUR, NITROGEN AND CONRADSON CARBON AND A SEPARATE RAFFINATE PHASE WHICH AMOUNTS TO ABOUT 80-90% OF SAID CRUDE OIL FEED, SAID PRECIPITATE BEING COLLECTED PRIMARILY IN SAID EXTRACT PHASE, SEPARATING SAID EXTRACT PHASE AND SAID RAFFINATE PHASE, REMOVING SAID EXTRACT PHASE FROM THE SAID DEASPHALTING ZONE, FILTERING SAID EXTRACT PHASE TO REMOVE SAID PRECIPITATE CONTAINING HEAVY METAL CONTAMINANTS, PASSING THE FILTER EXTRACT PHASE INTO A HIGH TEMPERATURE THERMAL CRACKING ZONE, CRACKING THE SAID METAL-FREE EXTRACT SUBSTANIALLY COMPLETELY TO METAL-FREE COKE AND HYDROGEN, RECOVERING SAID COKE AS A PREMIUM LOW METALS COKE, PASSING AT LEAST PART OF THE SAID HYDROGEN INTO A HYDROCRACKING ZONE, FRACTIONATING SAID RAFFINATE PHASE INTO THREE STREAMS, INCLUDING (1) A LIGHTER BOILING STREAM WHICH IS PASSED WITHOUT HYDROFORMING TO A HYDROFORMING ZONE WHERE IT IS HYDROFORMED IN THE PRESENCE OF HYDROGEN GAS, RECYCLING PART OF SAID HYDROGEN GAS FROM SAID HYDROFORMING ZONE TO SAID HYDROCRACKING ZONE, (2) AN INTERMEDIATE STREAM WHICH IS REMOVED FROM THE SYSTEM AS PRODUCT, AND (3) A BOTTOMS STREAM WHICH IS PASSED WITHOUT HYDROFINING INTO THE SAID HYDROCRACKING ZONE CONTAINING A CATALYST COMPRISING PALLADIUM ON AN ALUMINUM SILICATE MOLECULAR SIEVE WHERE IT IS HYDROCRACKED IN THE PRESENCE OF THE RECYCLE HYDROGEN FROM THE SAID HYDROFORMING ZONE AND HYDROGEN FROM SAID THERMAL CRACKING STEP, RECOVERING A LOW BOILING HYDROCRACKATE NAPHTHA FRACTION WHICH IS REMOVED FROM THE SYSTEM AND A HIGHER BOILING HYDROCRACKATE NAPHATHA FRACTION WHICH IS PASSED TO SAID HYDROFORMING ZONE, AND RECOVERING A HIGH QUALITY FUEL FROM THE SAID HYDROFORMING ZONE.

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