US3502571A - Catalytic conversion of hydrocarbonaceous black oil - Google Patents

Description

March 24, 1970 Malte-up Hydrogen Make-up Hydrogen F. sToLFA 3,502,571

CATALYTIC CONVERSION OF HYDROCARBONACEOUS BLACK OIL Filed Dec. 27, 1967 Q 0mm uam/0 9 arman/1 A TTORNE'YS United States Patent 3,502,571 CATALYTIC CONVERSION F HYDROCAR- BONACEOUS BLACK OIL Frank Stolfa, Park Ridge, Ill., assignor to Universal Oil Products Company, Des Plaines, Ill., a corporation of Delaware Filed Dec. 27, 1967, Ser. No. 693,925 Int. Cl. Cg 13/02 U.S. Cl. 208-108 10 Claims ABSTRACT OF THE DISCLOSURE The use of a metal phthalocyanine catalyst for the conversion of hydrocarbonaceous black oil into lowerboiling, normally liquid hydrocarbon products. The thermally stable phthalocyanine catalyst is employed in an amount within the range of about 250 p.p.m. to about 5000 p.p.m., based upon the weight of the black oil; preferred metal phthalocyanine catalysts are selected from Groups V, VI and VIII, and especially those containing cobalt, nickel, platinum, vanadium and molybdenum. A phthalocyanine-containing residuum fraction is recycled to combine with the black oil, necessitating only a minor quantity of additional metal phthalocyanine catalyst in order to maintain the desired concentration thereof within the reaction chamber.

APPLICABILITY OF INVENTION The invention described herein is adaptable to a process for the conversion of petroleum crude oil, as well as the heavier fractions derived therefrom, into lower-boiling hydrocarbon products. More specifically, the present invention is directed toward a process for converting atmospheric tower bottoms products, vacuum tower bottoms products, crude oil residuum, coal oil extracts, topped crude oils, tar sand oil extracts, etc., all of which are referred to in the art as black oils.

Crude oils, particularly the heavy oils extracted from tar sands, vacuum residuum, that resulting from the liquefaction of coal, etc., generally contain high molecular weight sulfurous compounds in exceedingly large quantities. In addition, these black oils conta-in excessive quantities of nitrogenous compounds, high molecular weight organo-metallic complexes, comprising nickel and vanadium, and asphaltic material. At the present time, an abundant supply of such hydrocarbonaceous material exists, most of which has a gravity less than 20.0 API, and a significant proportion of which has a gravity less than about 10.0 API. This material is generally further characterized by a boiling range which indicates that 10,0% or more, by volume, boils at temperatures above about l050 F. The conversion of at least a portion of the heavier boiling material into distillable hydrocarbonsi.e. those boiling below a temperature of about 1050 1:.- has hitherto been considered economically non-feasible. However, the abundant supply thereof virtually demands conversion for the purpose of satisfying the ever-increasing need for greater quantities of lower-boiling distillables.

Exemplary of those charge stocks, to which the present invention is particularly adaptable, include a vacuum tower bottoms product having a gravity of 7.l API and containing 4.1% by weight of sulfur and 23.7% by weight of asphaltics; a topped Middle-East Kuwait crude oil, having a gravity of 11.0 API, and containing 10.1% by weight of asphaltics and 5.2% by weight of sulfur; and, a vacuum residuum having a gravity of 8.6 API, containing 3.0% by weight of sulfur and more than 4000 p.p.m. of nitrogen, having a 20.0% volumetric distillation temperature of 1055 F. The principal difficulties, accompanying the conversion of black oils, arise primarily from the presence of the asphaltic material. This 3,502,571 Patented Mar. 24, 1970 ice asphaltic material consists of extremely high molecular weight, nondistillable coke precursors, insoluble in light hydrocarbons such as pentane or heptane, which are often found to be complexed with hetero compounds including nitrogen, metals and sulfur.

PRIOR ART While it must be acknowledged that the literature is replete with descriptions of processes of various types, designed to effect the conversion of black oils into lowerboiling hydrocarbons, a perusal of the art reveals little with respect to the non-fixed bed method of catalytic processing. For example, many literature references and/or publications might be found which disclose deasphalting followed by crack-ing of the resulting normally liquid product, desalting followed by halogen hydride treatment to coagulate the metallic-containing asphaltics, etc. It is significant that previously described processing schemes for the catalytic conversion of black oils appear to `favor a slurry-type process wherein a solid catalytic composite, in finely divided, .powdery form, is intimately admixed with the liquid charge, the resulting slurry being brought to reaction conditions in a reaction chamber. With these techniques, great expense is incurred in the reco'very of spent catalyst from the reaction chamber eflluent, accompanied by extensive regeneration facilities necessary to permit re-use of the catalyst. With respect to the ,so-called unsupported catalytic slurry-type processes, in which a compound is employed as the catalyst, the compound generally undergoes transformation into a non-catalytic form. This subsequently not only must be removed from the various product effluent streams, but must necessarily be converted into the catalytic form originally employed.

With respect to catalytic processing of hydrocarbonaceous black oils, two principal approaches have ibeen advanced: liquid-phase hydrogenation and vapor-phase hydrocracking. In the former, liquid-phase oil is passed generally upwardly), in admixture with hydrogen, into a fixedfluidized bed of catalyst particles. Although perhaps effective in converting at least a portion of the oil-insoluble metallic complexes, this type process is relatively ineffective with respect to asphaltics dispersed in the charge, since the probability of effecting simultaneous contact between the catalyst particle and the asphaltic molecule is at -best remote. Furthermore, since hydrogenation reactions are generally conducted at elevated temperatures of at least 500 C. (932 E), the retention of unconverted asphaltics, suspended in a free liquid-phase oil, for an extended period of time results in further occulation and agglomeration, adding to the diiculty of effecting conversion. Vapor-phase hydrocracking of black oil charge stocks containing substantial quantities of asphalitcs is, for all practical purposes, virtually ineffective. The high molecular weight asphaltic material tends to migrate immediately to the catalytically active centers and surfaces of the catalytic composite, thereby rendering the same ineffectual.

Briefly, the process of the present invention makes use of a class of Compounds which function as true catalysts; that is, they remain substantially unchanged while promoting the desired reactions. As hereinafter set forth, two principal advantages attendant the use of metallic phthalocyanine compounds reside in thermal stability up to temperatures as high as l500 F., and the fact that they are A principal object of the present invention is, therefore, to provide a catalytic process for the conversion of hydrocarbon residuals, or black oils, to minimum bottoms.

A corollary objective is to convert heavy hydrocarbonaceous materials in a non-fixed bed catalytic system in which the catalyst maintains a high degree of activity, and in which the catalyst can be internally recycled Without the need for regeneration or involved separation procedures.

Another object of the present invention is to convert a greater quantity of asphaltenic compounds into lowerboiling hydrocarbons, the greater proportion of the increased conversion being to those hydrocarbons which are considered normally liquid, as distinguished from normally gaseous.

In a broad embodiment, the present invention relates to a process for the conversion of hydrocarbonaceous Iblack oils to lower-boiling hydrocarbon products, which process comprises reacting said black oils with hydrogen in admixture with a metal phthalocyanine catalyst at conversion conditions including a temperature above about 500 F. and a pressure greater than about 500 p.s.i.g., and recovering lower-boiling hydrocarbons from the resulting conversion eiuent.

A more limited embodiment of the present invention involves a process for the conversion of hydrocarbonaceous black oil into lower-boiling hydrocarbon products, which process comprises the steps of: (a) reacting said black oil with hydrogen in admixture with a metal phthalocyanine catalyst at conversion conditions including a temperature above about 500 F. and a pressure greater than about 500 p.s.i.g.; (b) separating the resulting conversion eiuent to provide 1) a hydrogen-rich vapor phase, (2) a middle-distillate boiling range fraction, and, (3) a metal phthalocyanine-containing residuum fraction; (c) recycling said hydrogen-rich vapor phase and at least a portion of said metal phthalocyanine-containing residuum fraction to combine with said black oil; (d) hydrogenating at least a portion of said middle-distillate fraction and recycling the hydrogenated product to combine with said lblack oil; and, (e) recovering lower-boiling hydrocarbons.

`Other embodiments, as hereinafter set forth in greater detail, are principally concerned with particularly preferred processing techniques and ranges of various process variables. These, as well as other objects relating to the present inventive concept, will become evident from the following additional description of the process.

SUMMARY OF INVENTION As hereinbefore set forth, the principal function of the present invention resides in the conversion of hydrocarbonaceous black oils to minimum bottoms. That is, the maximum conversion of asphaltic charge stocks to distillable, lower-boiling hydrocarbon products, while simultaneously minimizing the quantity of both the residuum as well as the light, normally gaseous hydrocarbons including methane, ethane and propane. The present process is effected by reacting the hydrocarbonaceous black oil with hydrogen in admixture with a catalyst which is soluble in the heavier fractions of the charge stock. Thus, the process may be referred to as a modified slurry-type conversion process. However, the catalytic agent is an unsupported metallic complex from the group of metal phthalocyanine compounds. While metallic phthalocyanine derivatives are known for all eight groups of the Periodic Table, Phthalocyanine Compounds, Moser and Thomas, Reinholdt Publishing Company, page 105, 1963, the preferred derivatives are those which are thermally stable to temperatures as high as 1500 F. and whichare soluble in the hydrocarbonaceous black oils, or which can be made soluble for example by alkylation with heavier hydrocarbons. The preferred metal phthalocyanine derivatives are those containing copper, beryllium, barium, titanium, tin, hafnium, vanadium, antimony, chromium, molybdenum, iron, cobalt, nickel, palladium, platinum, mixtures of two or more etc. Of this group, the particularly preferred phthalocyanine derivatives are those containing cobalt, iron, vanadium, nickel, copper and/or platinum. The metallic phthalocyanine derivative is admixed with the charge stock in the amount of about 250 p.p.m. to about 5000 p.p.m., Iby weight of said black oil charge stock, and preferably intermediate concentrations of from 500 p.p.m. to about 1500 p.p.m. are employed.

The total charge to the reaction chamber, indicating a liquid combined feed ratio in the range of about 1.5 to about 2.5 is heated to a temperature above about 500 F., and preferably within the range of about 600 F. to about 800 F. Since the reactions lbeing effected are primarily exothermic, a temperature rise within the reaction chamber will be experienced. The precise temperature to which the total charge to the reaction zone is heated is determined, therefore, by the reaction chamber peak temperature, the latter being maintained within the range of from about'700" F. to about 900 F. The quantity of hydrogen is based upon the amount of fresh hydrocarbon charge stock, exclusive of liquid recycle, and is in the amount of from about 6000 to about 30,000 standard cubic feet per barrel thereof. The reaction chamber will be maintained under an imposed pressure within the range of about 500 to about 5000 p.s.i.g. Intermediate pressure levels are generally preferred, and include pressures within the range of about 1500 to about 3500 p.s.i.g.

Residence, or contact time, within the reaction chamber, is obtained by providing the chamber with any of the well-known mechanical devices such as side-to-side pans, sieve decks, disc and donut trays, etc. Residence time will generally range from about thirty seconds to about two minutes. The precise residence time for a given charge stock is a function of temperature and the UOP K-factor. For example, a charge stock having a K-factor of 12.6 characteristics of a highly, easily cracked paraffinic stock, will experience a lower residence time, at a given temperature, than a charge stock having a K-factor of about 11.2, characteristic of a highly refractory material. The UOP K-factor is dened in detail in Chemical Process Principles, Part I, Hougen and Watson, John Wiley and Sons, pp. 330-331, (1947). The hydrocracked product effluent is initially separated to provide a hydrogen-rich gaseous phase to be recycled to the reaction chamber in admix ture with the fresh hydrocarbon charge stock. Make-up hydrogen from any suitable external source, to supplant that hydrogen consumed in the process and removed therefrom by way of solution loss, is added to the process. The normally liquid portion of the remainder of the reaction chamber effluent is then further separated in a suitable fractionation system to provide the particularly desired product streams. In a preferred embodiment, at least a portion of the product effluent, having a boiling range of from about 400 F. to about 650 F., is hydrogenated in a suitable hydrogenation system to provide a diluent stream which is recycled to combine with the fresh hydrocarbon charge stock. As hereinbefore set forth, the combined feed ratio of the liquid charge to the reaction chamber will be within the range of about 1.5 to about 3.5; for present purposes, the combined feed ratio is defined as the total liquid charge to the reaction chamber divided by the quantity of fresh charge. Other operating conditions and preferred operating techniques will be given in conjunction with the following description of the present process. In further describing the process, reference will be made to the accompanying figure which illustrates one embodiment of the present invention.

DESCRIPTION OF DRAWING In the drawing, the embodiment is presented by means of a simplified flow diagram in which details such as pumps, instrumentation and controls, heat-exchange and heat-recovery circuits, start-up lines, compressors, valving and similar hardware have been omitted as being nonessential to an understanding of the techniques involved. The use of such miscellaneous appurtenances, to modify the process, are well within the purview of one skilled in the art of petroleum refining techniques.

For the purpose of demonstrating the illustrated embodiment, the drawing will be described in connection with the conversion of Vcnezuelian reduced crude oil of which about 60.0% by volume boils above a temperature of about 1050 F. This reduced crude has a gravity of 8.7 API, a UOP K-factor of 11.4, a Conradson Carbon Factor of 13.6% by weight, and contains about 4.3% by weight of sulfur and 6100 p.p.m. of nitrogen. It is understood that the. charge stock, stream compositions, operating conditions, design of fractionators, separators and the like, are exemplary only, and may be varied widely without departure from the spirit of my invention, the scope of which is defined by the appended claims.

The fresh charge stock in line 1 is admixed with a hydrogen-rich gaseous phase in line 2, the source of which is hereinafter described. To this mixture is added a catalyst-containing recycle stream from line 3. The overall combined feed ratio is 2.0. The recycled stream in line 3 contains 1000 p.p.m. of cobalt phthalocyanine, based upon the weight of the fresh charge stock entering the process via line 1. The hydrogen being recycled by way of line 2 is in an amount of about 10,000 s.c.f./bbl. of fresh charge stock. Following suitable heat-exchange with various hot ellluent streams, which technique is not illustrated, the combined charge enters heater 4 wherein the temperature is raised to a level of about 725 F., the heated mixture passing through line 5 into reaction chamber 6, the latter maintained at a pressure of about 3000 pounds per square inch gauge. The exothermicity of the reactions being effected within reaction chamber 6 produces a peak temperature of about 825 F., which increase in temperature results from a residence time of about 45 seconds.

The mixed-phase product effluent is withdrawn from reaction chamber 6 by way of line 7, and, following its use as a heat-exchange medium, whereby the temperature thereof is lowered to a level below about 750 F., is introduced into hot separator 8. This vessel is maintained at essentially the same pressure as reaction chamber 6, allowing only for the pressure drop due to fluid flow through the system. A principally vaporous phase is withdrawn from hot separator 8 through line 9, and a principally liquid phase is withdrawn through line 10. The greater proportion of the vapor phase in line 9, exclusive of hydrogen and light normally gaseous material, consists of hydrocarbonaceous material boiling below about 700 F., while the liquid phase in line 10 is principally 700 F.-plus hydrocarbonaceous material. The principally vaporous phase continues through line 9 and, after suitable heat-exchange and cooling, is passed into cold separator 11, the latter being maintained at a temperature within the range of about 60 F. to about 140 F. A hydrogenrich gaseous phase is withdrawn from cold separator 11 by fway/of line 2, and is recycled via compressive means not illustrated to combine with the fresh hydrocarbon charge stock in line 1. Make-up hydrogen, in an amount of about 1200 standard cubic feet per barrel of fresh hydrocarbon charge stock, is added to the system by way of line 12.

A normally liquid hydrocarbon phase is withdrawn from cold separator 11 by way of line 33 and is introduced into fractionator 13 by way of line 10. In a commercially-scaled unit, hot separator 8, cold separator 11 and fractionator 13 are designed into an integrated, relatively intricate Separation system whereby the conversion product effluent in line 7 is separated to provide a hydrogen-rich recycled gas phase shown in line 2 and the various desired normally liquid component streams. Such separation systems are well known and understood by those skilled in the art and, since the design of such systems are not essential to the present inventive concept, they are not further described and/or illustrated herein. For present purposes, it will suffice to indicate that the product ellluent in line 7 is separated to provide the hydrogen-rich recycled gas stream in line 2, the remainder of the product effluent being introduced into fractionator 13 by way of line 10.

Fractionator 13 serves to separate the normally liquid hydrocarbon product into a naphtha stream boiling up to about 400 F., and leaving fractionator 13 as an overhead product stream in line 14. A middle-distillate fraction, consisting primarily of those hydrocarbons boiling from about 400 F. to about 650 F., is withdrawn from fractionator 13 by way of line 17, and is introduced thereby into stripper 18. A suitable stripping medium, for example steam, is introduced into stripper 18 by way of line 19 and serves to strip those normally liquid hydrocarbons boiling in the gasoline boiling range from the middle-distillate, which gasoline boiling range hydrocarbons are re-introduced into the fractionator by way of line 21. The middle-distillate fraction, substantially free from gasoline boiling range hydrocarbons, is introduced by way of line 20 into hydrogenation reactor 22, after being admixed with a hydrogen-rich recycle gas in line 23. Hydrogenation reaction systems, suitable for utilization in a preferred embodiment of the present invention are well-known and well-described Within the prior art. Briefly, however, such a system generally consists of one or more catalytic reaction zones, a high-pressure cold separator, employed to provide a principally vaporous phase and a hydrogenated, normally liquid product ellluent. The vapor phase is generally recycled Within the hydrogenation system, make-up hydrogen ibeing added thereto from a suitable external source. Suitable catalytic `composites can be characterized as comprising at least one metallic component having hydrogenation activity, which component is combined with a refractory inorganic oxide carrier material. The precise composition and method of manufacturing the catalytic composite is not considered to be essential to the present process. Suitable metallic components are those selected from the Groups VI-B and VIII of the Periodic Table, as indicated in the Periodic Chart of the Elements, Fisher Scientific Company, -1 95 3. Suitable refractory inorganic oxide carrier material includes alumina, silica, zirconia, magnesia, titania, boria, strontia, hafnia, and mixtures of two or more including silica-alumina, alumina-silica-boron phosphate, aluminazirconia, etc.

The hydrogenated product eflluent is withdrawn from hydrogenation reactor 22 via line 25, and is introduced thereby into cold separator 26. A hydrogen-rich gaseous phase is withdrawn through line 23, being combined with the middle-distillate charge in line 20. As required to maintain the desired concentration of hydrogen in hydrogenation reactor 22, make-up hydrogen is added to the system by way of line 24. The hydrogenated normally liquid product eflluent is withdrawn from separator 26 by way of line 27, and at least a portion is recycled through line 3 to combine with the fresh hydrocarbon charge stock. That portion of the hydrogenated product eilluent not required as recycle is withdrawn as a product of the process by way of line 28. In general, the hydrogenated diluent continuing through lines 27 and line 3 as liquid recycle will be in an amount within the range of about 10.0% to about 50.0% by volume, based upon the quantity of fresh hydrocarbon charge stock.

The remainder of the conversion product ellluent is withdrawn from fractionator 13 by way of line 15, being introduced into vacuum column 16. Vacuum column 16 functions at subatmospheric pressures in the range of about 40 to about 80 mm. of Hg, absolute, and serves to further segregate the product ellluent to provide a heavy vacuum gas oil boiling in the range of about 850 F. to about 1050 F. in line 30 and a light vacuum gas oil boiling in the range of about 650 F. to about 850 F. in line 29. The l050 F.-plus material, commonly referred to as a residuum, is withdrawn through line 31. About 5.0% to about 20.0% Iby weight of the residuum fraction continues through line 31 as a drag stream. The remainder thereof is diverted through line 3, is ladmixed with the hydrogenated diluent in line 27 and continues to combine with the fresh hydrocarbon charge stock in line 1. To compensate for the quantity of phthalocyanine catalyst removed from the system via the drag stream in line 31, additional catalyst is introduced by way of line 32. As hereinbefore set forth, design considerations for any given commercially-scaled installation will dictate various fractionation/ separation schemes to handle the reactor chamber eluent in line 7. For example, in a situation where a portion of the hydrogenated middle-distillate is not utilized as a diluent in line 27, it will generally be necessary to divert a portion of the heavy vacuum gas oil in line 30 to combine with the fresh hydrocarbon charge stock in order to maintain the combined feed ratio to reaction chamber 6 at the selected level. Therefore, it is understood that the schematic ow diagram presented in the accompanying drawing is for illustrative purposes only.

EXAMPLE The following example is presented for the purpose of further illustrating the process of the present invention and the benets aiorded through the utilization thereof in maximizing the production of distillable hydrocarbons from hydrocarbonaceous black oils. The charge stock was a vacuum column bottoms fraction having a 20.0% volumetric distillation temperature of 1055 F. Other pertinent charge stock properties include a gravity of 8.6 API., 3.0% by weight of sulfur, about 4200 p.p.m. of nitrogen, a UGP K-fact-or of 11.2 and a Conradson Carbon Residue of 17.7 weight percent.

Two operations were edected at a heater transfer temperature of about 740 F., resulting in a reaction chamber peak temperature of about 840 F. The reaction chamber was maintained under an imposed pressure of 3000 p.s.i.g., and the hydrogen concentration was 10,000 standard cu'bic feet per barrel, based upon the fresh hydrocarbon charge stock. The combined feed ratio of the reaction chamber was 2.0, the combined feed consisting of the vacuum bottoms charge stock, 25.0% of a hydrogenated diluent and 75.0% of a substantially gasoline-free cracked hydrocarbon stream having an end boiling point of about 1050 F.

The second operation, designated in the following Ta'ble as Run B, was effected with the addition of co- 4 balt phthalocyanine to the fresh hydrocarbon charge stock in an amount of 1000 p.p.m. by weight thereof. A comparison of the two oeprations is presented in the following table:

TABLE.-COMPARATIVE RESULTS I claim as my invention:

1. A process for the conversion by hydrocracking of hydrocarbonaceous black oil into lower-boiling hydrocarbon products which comprises reacting said black oil with hydrogen in admixture with a metal phthalocyanine catalyst at conversion conditions including a temperature above about 500 F. and a pressure greater than about 500 p.s.i.g., and recovering lower-boiling hydrocarbons from the resulting conversion etiluent.

2. The process of claim 1 further characterized in that said phthalocyanine catalyst contains a metal selected from the group consisting of the metals of Groups V, JI and VIII of the Periodic Table.

3. The prcess of claim 2 further characterized in that said catalyst is vanadium phthalocyanine.

4. The process of claim 2 further characterized in that said catalyst is moiybdenum phthalocyanine.

5. The process of claim 2 further characterized in that said catalyst is cobalt phthalocyanine.

6. The process of claim 2 further characterized in that said catalyst is platinum phthalocyanine.

7. The process of claim 2 further characterized in that said catalyst is nickel phthalocyanine.

8. A process for the conversion by hydrocracking of hydrocarbonaceous black oil into lower-boiling hydrocarbon products which comprises the steps of:

(a) reacting said black oil with hydrogen in admixture with a metal phthalocyanine catalyst at conversion conditions including a temperature above about 500 F. and a pressure greater than about 500 p.s.i.g.;

(b) separating the resulting conversion eluent to provide (l): a hydrogen-rich vapor phase, (2) a middledistillate boiling range fraction, and (3) a metal phthalocyanine-containing residuum fraction;

(c) recycling said hydrogen-rich vapor phase and at least a portion of said metal phthalocyanine-containing residuum fraction to combine with said black oil;

(d) hydrogenating at least a portion of said middledistillate fraction and recycling the hydrogenated product to combine with said black oil; and

(e) recovering lower-boiling hydrocarbons as products of the process.

9. The process of claim 8 further characterized in that said black oil is reacted with hydrogen in admixture with from about 250 p.p.m. to 5000 p.p.m. of a metal `phthalocyanine catalyst.

10. The process of claim 8 further characterized in that said conversion eluent is further separated to provide a It should be noted that the method of the present invention resulted in 10.0 volume percent additional distillable hydrocarbons, accompanied yby the production of only 0.4% by Weight of additional normally gaseous material (C1-C4). Of further interest is the fact that a greater degree of hydrodesulfurization was effected. Design considerations indicate further that the continuous addition of metal phthalocyanine, to replenish the system for that removed in the drag stream, is only from about 150 p.p.m. to about 400 p.p.m. per barrel of fresh hydrocarbon charge.

The foregoing specification and example indicate the means iby which the present process is effected and the benefits afforded through the utilization thereof.

heavy vacuum gas oil fraction, at least a portion of which is recycled to combine with said black oil.

References Cited DELBERT E. GANTZ, Primary Examiner A. RIMENS, Assistant Examiner US. Cl. X.R.

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