US3472760A - Process for converting asphaltenic oils and olefinic gasolines to high-value petroleum products - Google Patents

Description

Oct. 14, 1969 N. PATERSON 3,472,760

PROCESS FOR CONVERTING ASPHALTENIC OILS AND OLEFINIC GASOLINES TO HIGH-VALUE PETROLEUM PRODUCT Filed Dec. 4, 1967 2 SZ1eets-Sheet 1 I6\ 7 EXTRACT PHASE 1/ o 2 u. 15 2 IE0 2 FEED .1 10 o u 22 IO 21 r g (Ia-C10 SOLVENT 20 a v I I R F T 1/ a 26 v 27 AFINAE 25 i PHASE v 29 0 so 29 2 Z .24 A,

OLEFINIC uz GASOLINE n1 mN 1a F|G.1

INVENTOR NORMA/V J. P4 rsnsozv BY #2 9,227;

dofmmaiv ATTORNEYS ecs are Us. Cl. 208-86 8 Claims I ABSTRACT F THE DISCLOSURE A process for the conversion of an asphalteneand metals-containing hydrocarbon oil to products boiling above 250 P. which comprises separating the oil by solvent deasphaltening into a paraflinic naphthenic extract phase and an aromatic raflin'ate phase so that the bulk of the metals-are concentrated in the raflinate phase; contacting the extract phase with HF to'remove polynuclear aromatics and other heavy maltenes as well as metals from the extract'phase; combining the HF-removed materials with the rafiinate phase and olefinic gasoline; and visbreaking the combined material to produce highvalue end products and fuels for other conversion processes. Sulfur may be present'in the feed, and H 8 may be added to the visbreaker. A portion of the visbroken product may be vacuurn'pitch stripped'and subjected to partial oxidation. Y

. BACKGROUND I THE INVENTION The present invention relates to the conversion of hydrocarbons and, more particularly, toa highly integrated process in which solvent deasphaltening, hydrogen fluoride demetalation, and visbreaking 'are utilized to minimize production of low-quality gasoline and enhance produc tion of higher-boiling materials suitable for use as hydro cracker feed.

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 petroleum process and conversion operations, such as-hydrofining and hydrocracking,.and upon combustion equipment in which such petroleum fractions are burned as fuels. In the high boiling fraction or residual type fuels, such contaminants attack the refractories used to line boilers and combustion chambers, cause s'lagging and the buildup of deposits upon boiler tubes, and severely corrode metallic surfaces with which they come into contact. v

Further, well-known difficulties'have been encountered in attempts to convertasphaltenes containing refractory types of sulfur compoundsinto gasoline. Gasoline blend stocks must be relatively free of sulfurin order to have good susceptibility to leadalkyls for octane improvement. Sulfur is particularly objectionable in fuel oils since. it burns mainly to sulfur dioxide which is highly corrosive under certain temperature conditions and contributes to air pollution.

Further, it is known that some of the productsordinarily produced, by standard refinery processes are of too low quality for use as motor fuels or jet fuels because of. their particular chemicals structure; despite the fact that,

upgrade such products to higher value materials which.

either may have values as finished products in their own right or may be used as feed to processes, such as hydrocracking, which have the ability to produce high-quality finished products.

SUMMARY OF THE INVENTION The present invention is a process whereby an asphalteneand metals-containing hydrocarbon oil is converted into high-quality products and feed for processes capable of producing high quality products, while at the same time minimizing production of some low-quality products.

This process involves, in its broadest form, contacting an asphalteneand metals-containing hydrocarbon oil with a light paraffinic solvent in a deasphaltening zone, forming an asphaltand metals-rich reaffinate phase and an asphaltand metals-lean extract phase, withdrawing these phases separately from the deasphaltening zone, contacting the extract phase with HF in a contacting zone, separating the efliuent of the contacting zone into a lighter portion and a heavier portion, said heavier portion comprising polynuclear aromatics, metals, and the bulk of the HF, combining at least a portion of said heavier portion with the rafiinate phase, and then visbreaking the combined phases in the presence of added olefinic gasoline to produce products boiling above 250 F.

In a narrower embodiment of the invention, a portion of the visbroken products is passed to a vacuum pitch stripper wherein it is" converted into a light stripped phase and a heavy stripped phase containing metals.

In a still narrower embodiment, at least a portion of the heavy stripped phase from the vacuum pitch stripping zone is converted to hydrogen in a partial oxidation zone and the metals are recovered.

BRIEF DESCRIPTION OF II-IE DRAWINGS FIG. 1 illustrates schematically a typical arrangement of the process units and flow streams which constitute the basic steps in the process of this invention. Auxiliary equipment often commonly associated with these basic steps is also shown.

FIG. 2 illustrates schematically the preferred embodiments of the process and shows in a typical example how the process of this invention might be integrated into a refinary complex.

DETAILED DESCRIPTION OF THE INVENTION 2 wherein it is contacted With a deasphaltening solvent which enters zone 2 through line 3. Typical solvents suitable for use in this process are the C -C paraflins, particularly propane. In the deasphaltening zone 2, the feed is separated into two phases. .The lighter extract phase contains the bulk of the solvent, the light parafiinic and naphthenic components of the feed (which are commonly referred to collectively as the maltenes), a small portion of the feed metals, and a portion of the sulfur that may have been present in the feed. The heavier rafiinate contains a small amount of solvent, the heavier asphaltene components of the feed, and the bulk of the metals and sulfur. The extract phase is removed from deasphaltening zone 2 through line 4 and passed to solvent recovery zone 5 wherein the solvent is separated and removed a through line 6. The rafiinate phase is removed from deasphaltening zone 2 through line 7 and passed to solvent recovery zone 8 wherein the solvent is separated and" removed through line 9. The solvent in lines 6 and 9 may be separately recovered or may be recycled back to deasphaltening zone 2 through line 3.

The solvent-free maltenes are passed from solvent recovery zone 5 through line to HF contacting zone 11 wherein they are contacted with hydrogen fluoride which enters HF contacting zone 11 through line 12. The hydrogen fluoride may be in the form of gaseous HF or may be anhydrous hydrogen fluoride or may be in an aqueous solution of concentrated hydrofluoric acid. A minor amount of other materials, such as BF may also be present with the HF, if they do not impair the effectiveness of the HF. The preferred form will depend on the temperature at which HF contacting is to be done and the type of equipment which is to be used. Generally, the HF converts the small amount of metals in the extract phase to insoluble metal fluorides and at the same time extracts some of the polynuclear aromatics which are removed as a liquid phase carrying the insoluble metallic fluoride contaminants in suspension. The effluent of zone 11 is removed through line 14 and passed into separator 15 wherein a demetallized desulfurized oil containing the lighter portions of the maltenes is removed overhead through line 16 and passed to HP removal zone 17. HF removal zone 17 is commonly a stripper although other conventional means of separating HF from an oil stream may be used. The HF separated is removed from zone 17 through line 18 while the demetallized oil is removed through line 19 and passed to whatever further processing is desired. As will be illustrated below, this further processing may include hydrocracking, reforming, or other well-known refining processes.

The HF layer, which comprises the heavier portion of the maltenes, including the heavy polynuclear aromatics containing the suspended metallic fluorides and any sulfur, along with the remainder of the HF, is removed from zone 15 through line 20 and passed to HF separation zone 21. HF separation zone 21 is similar to HF separation zone 17. The separated HF is removed through line 22. The recovered HP in lines 18 and 22 is commonly recycled to HF contacting zone 11 and line 12 by means not shown, although the material in either or both lines 18 and 22 may be separately recovered or withdrawn from the process for other uses. The HF-free heavier portion of the maltenes which comprises highly aromatic materials is removed from separator 21 through line 23. In the event some traces of HF or fluorine still remain in the oil, the oil may be water washed in water washing zone 24 and then passed through line 25 to defluorination zone 26. Water enters water washing zone '24 through line 27, and the waste water and extracted fluorine are withdrawn through line 28. Defluorination zone 26 contains bauxite, alumina, or any other conventional fluorine absorbent.

The solvent-free raffinate phase containing the heavy asphaltenes and the bulk of the metals is withdrawn from solvent recovery zone 8 through line 29. A quantity of olefinic gasoline enters through line 30 and is combined with the rafiinate phase. Defluorinated aromatic maltenes are withdrawn from zone 26 and passed through line 31 to be combined with the ratfinate phase and olefinic gasoline. In the event that aromatic maltenes are sufliciently fluorine-free when they leave zone 21, they may be passed directly to line 31 for combination with the raflinate phase and olefinic gasoline without being water washed and defluorinated in zones 24 and 26. The combined materials are passed through line 32 to visbreaking zone 33. Zone 33 generally comprises a conventional visbreaker and performs mild thermal cracking of the asphaltenes in the presence of the aromatics, olefinic gasoline, and suspended metallic fluoride contaminants. During the bisbreaking operation, usually conducted at low temperatures and over extended time periods to favor polymerization, some of the olefinic materials and gasoline constituents are alkylated and polymerized to create higher boiling gas oils. The ultimate result is a consumption of low-value olefins and production of valuable higher boiling aromatic gas oils, middle distillates and heavier oils.

These gas oils by virtue of their aromatic composition are valuable feed stocks to conversion processes, such as hydrocracking, wherein high octane gasoline products are produced. Under certain operating conditions, a high heating value jet fuel of excellent thermal stability and freeze point may be produced from this type of feed stock. The visbroken materials are withdrawn from bisbreaking zone 33 through line 34 and passed to separation and whatever further processes may be desired. Although visbreaking zone 33 is generally operated as a thermal cracking zone, it may also be operated as a hydrovisbreaking zone, with hydrogen introduced at the coil inlet from an outside source through line 13. Under preferred conditions, the metallic constituents may be converted to the sulfides by the introduction of hydrogen sulfide along with the added hydrogen, whereby the asphaltene content of the charge is rapidly converted into liquid gas oils by hydrogenation and mild hydrocracking, thus increasing the yield of the desired heavier gas oil product. Under these circumstances the conversion of the added olefinic gasoline and other gasoline constituents proceeds as before but at an accelerated rate due to the catalytic effect of the heavy metal sulfides which promote splitting and hydrocracking of the parafiinic and cyclic compounds in the added and/or recycled gasoline.

In FIGURE 2, the process of this invention is described in more detail schematically and an illustration is given indicating how the process of this invention might be integrated into an overall refinery scheme. Examples are given below showing typical stream compositions and reaction conditions based on this illustration. Crude oil in line 101 is introduced into crude fractionation unit 102 wherein it is fractionated into several streams of differing boiling ranges. In a typical example, a C to 200 F. gasoline cut would be taken off overhead through line 103 and sent to gasoline blending. Near the top of the column, a 200-375 F. cut would be taken and passed through line 104 to catalytic reforming to produce additional gasoline. A 375 650 F. cut would be taken at a middle point in the column and passed through line 105 to hydrocracking and reforming to produce additional gasoline. Near the bottom of the column, a 650-l,000 F. cut of gas oil would be taken and passed through line 106 to hydrocracking to produce gasoline and jet fuel. The heavy residual material from the crude oil which would typically be a 1,000 F.+ residuum is taken from the bottom of the column through line 107 to deasphaltening zone 108 wherein it is contacted with a light solvent which enters zone 108 through line 109. The solvent separates the residuum into an extract phase containing maltenes which is withdrawn from deasphaltening zone 108 through line 110 and the raffinate phase containing the asphaltic material which is withdrawn from zone 108 through line 111. Solvent is separated from the two phases in zones 112 and 113, respectively; and the solvent is recycled through lines 114 and 115, mixed with any needed fresh solvent brought in through line 116, and all solvent is returned through line 109 to deasphaltening zone 108. In some cases Where the maltenes are particularly viscous, it may be desirable not to make a complete separation of solvent from the maltenes in zone 112 but rather to let some solvent act as a cutter stock and pass with the maltenes through line 117 to HF contacting zone 118.

In HF contacting zone 118, the maltenes and whatever metals and sulfur they contain are contacted with HF which enters through line 119. The HF converts the metals to insoluble metal fluorides which may be removed through line 120, although preferably they may be passed along with the maltenes and HF out of HF contacting zone 118 and separated at some later point. The treated maltenes pass through line 121 to separation zone 122 wherein the maltenes are fractionated and the lighter, less aromatic maltenes are removed through line 123 to HF separation unit 124 wherein any remaining suspension are removed from zone 122 through line 126 and passed into HF separation zone 127. The HP and solvent are separated and removed through line 128. They are mixed with HF and solvent coming from zone 124 through line 129, and the combined streams are recycled to zone 118 through line 130. The solvent-free, heavier aromatic maltenes, containing suspended metals and in some cases sulfur, are removed from zone 127 through line 131 and may, if necessary to remove remaining fluorine, be water washed in zone 132, into which water enters through line 133, and water and fluorine are removed through line 134. The maltenes are then passed through line 135 to defluorination zone 136 for a final bauxite, alumina, or similar treating to remove any residual fluorine. In some cases, it may be desirable to recycle some portion of the maltenes to the HF treating zone through line 137. Preferably, however, all the heavier maltenes pass through zone 136 and are withdrawn through line 138.

The ratfinate phase from the deasphaltening zone 108 which comprises the bulk of the asphaltenes and the heaviest aromatics and most of the metallic contaminants that were originally in the crude oil is passed from solvent separation zone 113 through line 139 and is combined with a quantity of olefinic gasoline which enters the system through line 140. The raflinate and the olefinic gasoline are in turn combined with the heavier HIP-treated maltenes, containing metals and sulfur in line 138, and the combined material is passed through line 141 into visbreaking zone 142. After visbreaking, under conditions which will be described below, the visbroken material is withdrawn through line 143 and passed into separation zone 144. The visbroken material is fractionated in zone 144 into a plurality of streams. In a typical operation, three streams would be produced: a naphtha stream, rich in olefins, withdrawn overhead from zone 144 and recycled at least in part to zone 142; a light gas oil stream, withdrawn through line 146 and preferably passed to further processing, such as hydrocracking; and a heavy fraction containing the metals and sulfur. Generally, the pressure of the visbroken material is reduced and its temperature is lowered by means of a combination pressure-reducing/quenching valve, placed in line 143 upstream of zone 144, in order to arrest the cracking reactions and to permit additional flashing of the products of reaction, in the visbreaker coil. The quenching material is preferably a portion of the recycled naphtha, passed from line 145 through line 147 to the quenching valve in line 143. Alternatively, a portion of the gas oil in line 146 can be' recycled through line 157 to serve, either alone or in combination with a' portion of the naphtha, as the quenching material The heaviest portion of the visbroken material, containing the metals and sulfur, is withdrawn from the bottom of zone 144 through line 148, is heated in furnace 149 in admixture with added steam and usually a light diluent oil, such as a portion of the light gas oil stream in line 146, and the'heated material is passed through line 150 into vacuum pitch' stripping zone 151. Here light materials are separated from the visbroken residuum and are passed through line 152 to hydrocracking or other processing. The remaining heavy material is passed by well known means to elemental sulfur and the carbon dioxide dehydrated and separated as a solid or liquid product. The hydrogen is used in various hydrogen-consuming processes within the refinery, such as hydrocracking. The metals are removed through line 156 and may, if there is sufficient economic incentive, be recovered or may be discarded as ash.

In the process of this invention, the inclusion of the HF-treated maltenes, which are highly aromatic, in the feed to the visbreaker permits visbreaking of the aramatic asphaltenes from the solvent deasphaltening process under more severe conditions than would be possible if the asphaltenes alone were to be visbroken. This is because the inclusion of the aromatic maltenes tends to solubilize the unstable fragments and asphaltenes formed during the thermal visbreaking operation as well as keeping the unstable compounds formed by any thermal cracking during visbreaking in solution and thus preventing their deposition in the visbreaker coil which would result in rapid coke formation necessitating premature shutdown of the visbreaker. The inclusion of the aromatic maltenes also appears to prevent the deposition of the metallic complexes that are present in the asphaltenes and the HF-treated maltenes when the metals have not previously been removed from the latter. Although some amount of water will be present in the visbreaker feed following the water washing of the maltenes, a small amount is preferentially injected into the visbreaker feed, thus increasing the velocity of the charge to the visbreaker. The shorter contact time thus resulting may be compensated for by the higher outlet temperatures which are permitted in the visbreaker since the formation of coke is inhibited by the inclusion of the HF-treated aromatic maltenes in the visbreaker feed. In contrast, visbreaking of asphaltenes alone would result in rapid coking at the severity conditions desirable in this process while, if less severe conditions were used to prevent coking, little or no conversion would result. Consequently, this process provides a method whereby the severity required in the visbreaker to convert a reasonable proportion of the asphaltenes can be obtained without unnecessarily rapid coke formation.

The inclusion of the olefinic gasoline, which may be obtained from a fluid catalytic cracking unit, a thermal reformer or cracker, or any other process which produces olefins boiling in the gasoline range, results in conversion of the olefinic gasoline in the visbreaker to give increased production of high boiling distillates due to polymerization and alkylation reactions occurring under the conditions of severe heat and pressure and in the presence of whatever fluorine or metal fluorides may still be present after the HF treating of the maltenes. This process includes a self-moderating feature, however; for the presence of aromatic maltenes reduces the tendency of the polymerization reactions to go to extremes and retains any high boiling polymers in solution. Many olefinic gasolines also are highly sulfurous or nitrogenous and tend to be highly poisonous to catalysts. Consequently, by visbreaking of the olefinic gasolines to polymerize and alkylate them to higher boiling materials, they are made more readily handled by downstream catalytic processes, such as hydrocracking. In such downstream processes, the sulfur and nitrogen may be more readily removed from the nonolefinic compounds, and more stable and valuable nonolefinic gasoline components may be pro duced. Recycling of the material boiling in and below the gasoline range permits either zero net gasoline production from the visbreaker or a net negative production of olefinic gasoline, since any olefinic gasoline which might have passed through the visbreaker unconverted is recycled to extinction. Thus, while olefinic gasoline passes into the visbreaker, there is no net production of gasoline following separation of the products from the visbreaker.

The middle cuts from the visbreaker may be passed on to hydrocracking or other conventional refinery processes to process gasoline, jet fuel and other high value products. The visbreaker tar or residuum is preferably passed to a pitch stripping zone to remove whatever light materials may still be included in the residuum, and these light materials serve as additional hydrocracker feed. Thus, the maximum amount of material suitable for processing to gasoline, jet fuel, and other high value products is obtained from the original crude oil. The remaining residual stripped tar, which contains suspended metals, is preferably passed to a partial oxidation zone wherein it is converted to hydrogen and carbon dioxide and the metals removed and, if desired, recovered. This hydrogen is used in hydrogen-consuming processes throughout the refinery to aid in conversion of the other portions of the crude oil to higher value products.

The solvent deasphaltening zone used in this process is a conventional deasphalter using a light paraflinic solvent, preferably in the C -C range. Propane and pentane are particularly preferred. The solvent to oil ratio may range from 3:1 to 12: 1. The deasphaltening zone is conventionally a tower with the temperature at the top of the tower on the order of 20-80 lower than that at the bottom of the tower. Average tower temperatures are in the range of 100-400" F., and pressures are sufficient to maintain all components in a liquid phase. The primary purpose of the solvent deasphaltening zone is to separate asphaltenes. Consequently, it is desired to take as high a yield of maltenes from the zone as possible. In a typical operation, the extract phase would contain a maximum of 0.5 weight percent asphaltenes (measured as n-pentane insoluble asphaltenes) and would constitute 5085 volume percent of the feed to the zone. The metals content of the extract would be 1250 p.p.m. or higher of metals measured as metallic vanadium, iron, nickel, and copper.

The HF treating zone, as well as the HF stripping zone, the water washing zone, and the bauxite defiuorination zone, are also conventional units. The HF treating zone is generally a tower designed for liquid-liquid contacting, and the internal portion is constructed of materials which are not readily susceptible to HF corrosion. The tower is operated at a temperature and pressure sufficient to maintain the maltenes and the HF in a liquid phase. In the event a minor portion of other components, such as BF is present with the HF, the temperature and pressure in the HF treating zone should be adjusted accordingly so that all components are maintained in the liquid phase. The exact temperature and pressure used will depend on the concentration of the HF, the presence or absence of any minor components with the HF, the boiling point and viscosity of the maltene fraction taken from the deasphaltening zone, and the presence or absence of any solvent remaining with the maltenes. Thus temperature and pressure may vary over a wide range and are not critical as long as all components are kept in the liquid phase.

The visbreaking zone is conventionally a furnace followed by one or more reaction chambers. Preferably there are a plurality of reaction chambers with alternating upflow and downfiow operation. In some instances, however, the use of reaction chambers involves the tendency of the oil to overcrack in the vapor phase, thus producing a larger amount of gasoline which must be separated and recycled. In order to maximize production of the desired gas oil hydrocracker feed, it is preferred to use a soaking coil either in the main furnace or in a secondary furnace so that polymerization reactions in the liquid phase predominate rather than the cracking reactions in the vapor phase which would occur in reaction chambers. A more preferred operation is the use of a visbreaker coil supplemented by a soaking coil, either in the same or a separate furnace, to provide a longer residence time in the visbreaking zone during Which increased alkylation and polymerization may take place. When a soaking coil is used, it is generally necessary to quench the outlet of the furnace to a temperature below 775 F. to arrest any cracking reactions that might be occurring and to prevent deposition of the coke in the bottom of the fractionator in which the visbroken materials are separated. The quenching material may be naphtha produced during visbreaking, a visbroken gas oil, or cooled stripped or unstripped tar. Other materials which might be used will readily be suggested to one skilled in the art; and all these equivalents are meant to be included within the scope and spirit of this invention, for the actual nature of the quenching material is not critical to the process of this invention.

Several examples will serve to illustrate the process of this invention:

Example 1 A feed of 100,000 b.p.o.d. of 21.5 API California crude oil is distilled in a conventional fractionation unit into 5,000 b.p.o.d. C 200 F. straight-run gasoline which is sent to gasoline blending; 10,700 b.p.o.d. of 200- 375 F. heavy naphtha which is sent to catalytic reforming; 22,300 b.p.o.d. of 375-650 F. light gas oil which is sent to hydrocracking; 31,500 b.p.o.d. of 6501,000 F. heavy gas oil which is sent to separate hydrocracking; and 30,500 b.p.o.d. 0f 1,000 F.+5.2 API residuum which contains 455 p.p.m. of iron, nickel and vanadium. This residuum is contacted in a deasphaltening zone with normal pentane to produce 24,400 b.p.o.d. of an 8.7 API maltene fraction and 6,100 b.p.o.d. of a 7.2 API asphaltene fraction. The maltene fraction contains 188 p.p.m. metals, and the asphaltene fraction contains 1,402 p.p.m. metals. The maltene fraction is HF treated and separated into 19,520 b.p.o.d. of a API light maltene stream containing 0.75 weight percent sulfur, 0.6 weight percent nitrogen and 8 p.p.m. metals, and 4,880 b.p.o.d. of a 1.9 API heavy maltene fraction containing 9.2 weight percent sulfur, 2.76 weight percent nitrogen and 871 p.p.m. metals. The 6,100 b.p.o.d. of deasphaltener asphalt and the 4,880 of HF treated heavy maltenes are combined with 500 b.p.o.d. of C -225 F. catalytically cracked light olefinic naphtha obtained from the catalytic cracking of California crude oil and 550 b.p.o.d. of recycled visbroken olefinic naphtha and are passed into the visbreaker along with one weight percent water. The visbreaker outlet temperature is 878 F., and the outlet pressure is 270 p.s.i.g. The product distribution from the visbreaker is 6.7 Weight percent 0.; material, no net production of C 350 F. material, 45 volume percent of 350-1,000 F. gas oil and the remainder 1,000 F.+ material. Overall conversion to 1,000 F. material is 55 volume percent.

Example 2 In this examle, the feeds and products to crude fractionation, deasphaltening, and HF treating are the same as in Example 1. In this example, however, the asphaltenes and heavy HF-treated maltenes are not combined with any external olefinic gasoline but are combined only with 545 b.p.o.d. of recycled visbroken olefinic naphtha and one weight percent water. The visbreaker outlet temperature is 875 F. and the outlet pressure is 250 p.s.i.g. Product distribution is 5.2 Weight percent C material, 0.5 volume percent C -350 F. naphtha, 41.8 volume percent of 350-1,000 F. gas oil, and the remainder 1,000 F.+ material. Total conversion to 1,000 F. material is 50 volume percent.

Example 3 Here again, the feed and products of the crude fractionation unit, deasphaltening zone, and HF treating zone are the same as in Example 1. The asphaltenes and HF- treated heavy maltenes are combined with 550 b.p.o.d. of recycled visbroken olefinic naphtha and 500 b.p.o.d. of C -400 F. olefinic naphtha from the thermal reforming of an S0 extracted material obtained from treated 320-500 F. kerosene distillates from a California crude i l Aromatic content of the reformed naphtha is 45 percent, and the sulfur content of the naphtha is 2 weight percent. Visbreaker outlet temperature is 870 F., and outlet pressure is 285 p.s.i.g. Water in the amount of one weight percent of feed is again injected. Product distribution is 8 weight percent C material, 5 volume percent C 350 F. material, 48.8 volume percent 3501,000 F. gas oil and the remainder 1,000 F. residuum. Total conversion to 1,000 F.-- material is 54 volume percent.

The above examples and specific operating conditions and flow systems are given for illustrative purposes only. It is apparent that many widely different embodiments of this invention may be made without departing from the scope and spirit thereof and, therefore, it is not intended to be limited except as indicated in the appended claims.

I claim:

1. A process for the conversion of an asphalteneand metals-containing hydrocarbon oil to products boiling above 250 R, which comprises:

(a) contacting said oil in a deasphaltening zone with a light paraflinic solvent and forming a rafiinate phase rich in metals and asphaltenes, and an extract phase lean in asphaltenes and metals;

(1)) withdrawing said phase separately from said deasphaltening zone;

(c) contacting said extract phase with HF in a contacting zone, and thereafter separating the effluent of said contacting zone into a lighter portion and a heavier portion, said heavier portion comprising metals, polynuclear aromatics, and the bulk of said HF;

(d) combining at least a portion of said heavier portion with said raflinate phase; and

(e) visbreaking in a visbreaking zone the combined materials of (d) in the presence of added olefinic gasoline to produce products boiling above 250 F.

2. The process of claim 1 wherein at least a portion of the effluent of said visbreaking zone is passed into a vacuum pitch stripping zone wherein it is converted into a light stripped phase and a heavy stripped phase, the latter containing metals.

3. The process of claim 2 wherein at least a portion of said heavy stripped phase is converted to hydrogen in a partial oxidation zone and said metals are recovered.

4. The process of claim 1 wherein sulfur is present in said hydrocarbon oil and is recovered as a reaction product of the process.

5. The process of claim 1 wherein there is a net negative production of olefinic gasoline.

6. The process of claim 1 wherein in said contacting zone said extract phase is contacted with HP in the form of anhydrous hydrogen fluoride.

7. The process of claim 1 wherein said visbreaking zone comprises a visbreaking coil and a soaking coil.

8. The process of claim 7 wherein the effluent of said visbreaking zone is quenched to a temperature below 775 F.

References Cited UNITED STATES PATENTS 2,847,353 8/1958 Beavon 20873 2,926,129 2/ 1960 Kimberlin et al 208251 2,800,433 7/ 1957 Read 20886 3,281,350 10/1966 Codet et al. 208309 HERBERT LEVINE, Primary Examiner US. Cl. X.R. 208106, 252, 30-9

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