US3444073A

US3444073A - Process of hydrogen treating asphaltic and maltene containing fractions

Info

Publication number: US3444073A
Application number: US579032A
Authority: US
Inventors: Harold Beuther; Bruce K Schmid
Original assignee: Gulf Research and Development Co
Current assignee: Chevron USA Inc
Priority date: 1966-09-13
Filing date: 1966-09-13
Publication date: 1969-05-13
Anticipated expiration: 1986-05-13
Also published as: BE703763A; DE1645755A1; FR1539239A; GB1168528A; DK116888B; NL6712384A

Description

May 13, 1969 H. BEUTHER ET AL 3,444,073

PROCESS OF HYDROGEN TREATING ASPHALTIC AND MALTENE CONTAINING FRACTIONS Filed Sept. 13. 1966 so 36 AL as /0L 4% :2} 344 {40 L. r\ 56 6 L $60 g {8 INVENTORS AMROLD Bil/77%)? a BRUCE K. SCI/MAO U.S. Cl. 208212 11 Claims ABSTRACT OF THE DISCLOSURE A process for the hydrogen treatment of asphaltic containing hydrocarbons which comprises separating the hydrocarbons into an asphaltene fraction and a maltene fraction and thereafter separately subjecting the asphaltene fraction to comparatively mild hydrogen treatment and separately subjecting the maltene fraction to comparatively severe hydrogen treatment.

Our invention relates to an improved process for the hydrogen treatment of heavy hydrocarbons.

Various techniques for the hydrogen treatment of heavy hydrocarbons have previously been suggested in the art. Most of these techniques have taken into consideration the fact that asphaltic containing stocks, i.e. stocks containing materials insoluble in propane, cannot be treated under conditions of great severity without adversely affecting the overall process due to the tendency of the asphaltic materials to form an excessive amount of coke on the catalyst, thereby creating unrealistically short catalyst life and cycle time. The art, therefore, has been inclined toward the employment of comparatively mild conditions for the hydrogen treatment of such stocks, thereby sacrificing conversion to obtain acceptable catalyst life. We have discovered a process whereby these asphaltic containing heavy hydrocarbon stocks can be treated so as to provide increased conversion While maintaining catalyst activity.

In accordance with our invention we have discovered a process for the hydrogen treatment of asphaltic containing heavy hydrocarbons boiling above about 900 F. which comprises first separating the hydrocarbons into an asphaltene fraction and a maltene fraction. As used in our specification and claims the term asphaltene describes those materials insoluble in pentane while the term maltene describes those materials soluble in pentane. Thus, for example, when a vacuum residue is subjected to solvent extraction with pentane the maltenes are contained in the extract phase while the asphaltenes are contained in the raflinate phase. The separated asphaltene fraction and the maltene fraction are then processed separately in accordance with our invention. Thus, the asphaltene fraction is separately subjected to hydrogen treatment under comparatively mild conditions after which at least one fraction boiling below about 1000 F. is recovered from the hydrogenated asphaltene fraction. The maltene fraction is also separately subjected to hydrogen treatment at comparatively severe conditions after which at least one fraction boiling below about 1000 F. is recovered from the hydrogenated maltene fraction.

The material is to be treated in accordance with our invention can be any asphaltic containing heavy hydrocarbon boiling above about 900 F. and preferably boiling above about 1000 F. Illustrative of such materials are vacuum residues from crude petroleum or shale oil, naturally-occurring heavy oils such as tar oil or pitch, or deashed coal. The terms asphalt and asphaltics as employed herein have their traditional meanings of describing hydrocarbon materials which are insoluble in propane.

3,444,073 Patented May 13, 1969 The operating conditions employed for the hydrogen treatment of the asphaltene fraction in accordance with our invention include a pressure from about 500 to about 3000 p.s.i.g., preferably from about 1000 to about 2500 p.s.i.g.; a liquid hourly space velocity from about 0.1 to about 5.0, preferably from about 0.3 to about 1.0; and a hydrogen feed rate from about 2000 to about 20,000 standard cubic feet per barrel (s.f.c./b.), preferably from about 5000 to about 10,000 s.c.f./b. The temperature employed in the treatment of the asphaltene fraction in accordance with our invention must be above about 600 F. and preferably is above about 700 F. The upper limits of the range of temperatures which can be employed in our process are quite critical and are determined by several factors. Thus, when the asphaltene fraction is treated in the absence of any extraneous materials, the temperature employed must not exceed about 775 F. and preferably is not above about 750 F. When the asphaltene fraction is treated in the presence of a diluent and a pressure of at least about 2000 psig. is employed, temperatures up to about 850 F. can at times be employed. Preferably, however, the temperature employed in such instances does not exceed about 820 F.

The diluents with which the asphaltene fraction can be admixed include hydrocarbons boiling at least 300 F. or more below the boiling range of the asphaltene fraction and mixtures thereof. Illustrative of such materials are the furnace oil, kerosene and naphtha fractions obtained from petroleum. We have found aromatic hydrocarbons to be particularly useful as diluents in our invention, such as, for example, any of the well known aromatic solvents including benzene, toluene, xylene, etc. as well as petroleum hydrocarbon fractions of the type mentioned above which have a high proportion of aromatic constituents. These diluents are generally employed with an asphaltene fraction in a quantity suflicient so that the resultant blend contains at least about 20 percent by weight of diluent and can contain up to about percent by weight diluent. We have found that if it is desired to treat an asphaltene fraction at a temperature above about 775 F. the diluent should be used in a quantity sufiicient to comprise at least about 50 percent by weight of the blend although lesser quantities of diluent can advantageously be employed at lower temperatures.

The employment of a diluent in the treatment of heavy hydrocarbons in accordance with our invention can at times be exploited to alter the type of products obtained. Thus, for example, if there is a demand for a low sulfur content residual fuel or other low sulfur content comparatively high boiling material, the employment of a diluent while maintaining the same throughput of the heavy hydrocarbon, either the asphaltene fraction or the maltene fraction, results in a reduction in the cracking effected while increasing the amount of sulfur removal. The result is a greater yield of higher boiling material with a reduced sulfur content.

The operating conditions employed in the hydrogen treatment of the maltene fraction in accordance with our invention include a temperature from about 750 to about 900 F., preferably from about 750 to about 850 R, which temperature is at least 25 F. and preferably 35 40 F. greater than the temperature employed for the hydrogen treatment of the asphaltene fraction; a pressure from about 500 to about 4000 p.s.i.g., preferably from about 1000 to about 2500 p.s.i.g.; a liquid hourly space velocity from about 0.2 to about 10.0, preferably from about 0.5 to about 3.0 volumes of maltene fraction per hour per volume of catalyst; and a hydrogen feed rate from about 2000 to about 20,000 s.c.f./b., preferably from about 5000 to about 10,000 s.c.f./ b.

The catalyst employed in either of the hydrogen treatment steps of our invention can be any of the catalysts well known in the art comprising a hydrogenating component composited with a carrier. Catalysts of this type can be comprised of any of the well known metallic hydrogenating components selected from the Group VI and Group VIII metals, their oxides, sulfides or mixtures thereof composited with any of the well known carrier materials either active or inactive such as, for example, the refractory metal oxides or mixtures thereof, particularly silica, alumina and magnesia. Particularly suitable catalysts include combinations of nickel, cobalt and molybdenum as well as nickel and tungsten supported on carriers having cracking activity such as, for example, silica-alumina, silica-magnesia and certain activated aluminas.

In particular embodiments the process of our invention includes the further treatment or processing of the materials obtained from one or both of the hydrogen treatment steps described above. In accordance with one of these particular embodiments of our invention the hydrogenated effiuent from the maltene hydrogen treating step is fractionated so as to separate a fraction boiling above about 1000 R, which fraction is recycled to the separation step wherein asphaltenes produced in the hydrogen treatment of the maltenes are separated and passed to the asphaltene hydrogen treating step, while the 1000 F.+ maltenes are passed to the maltene hydrogen treating step for further treatment along with the maltenes obtained from the fresh feed. In another embodiment of our invention, wherein particularly mild conditions are employed in the hydrogen treatment of the asphaltene fraction so as to minimize hydrocracking and maximize hydrogenation reactions, the efiluent from the asphaltene hydrogen treatment step is fractionated soas to separate that portion of the efiluent boiling above 1000 R, which portion is recycled to the separation step. In the separation step maltenes formed by the hydrogenation of the asphaltene fraction are separated and passed together with the maltenes from the fresh feed to the maltene hydrogen treatment step, while the 1000 F.+ asphaltenes are returned to the asphaltene hydrogen treatment step for further hydrogen treatment.

In certain instances the 1000 F.-]- fractions taken from the efiluents from both the asphaltene and maltene hydrogen treating steps can both be recycled to the separation step of our process.

In conjunction with any of the embodiments described immediately above the effluent from either the maltene or asphaltene hydrogen treating steps can be fractionated so as to obtain varying proportions of lower boiling fractions, such as, for example, materials boiling in the gasoline, naphtha and furnace oil ranges as well as materials boiling in the heavy gas oil or vacuum gas oil range from about 675 or 725 F. up to about 1000 F. Each of these fractions can then be further treated in accordance with more conventional refinery techniques, such as, for example, reforming of the gasoline and naphtha fractions, desulfurization or hydrocracking of the furnace oil fraction and hydrocracking or catalytically cracking the heavy gas oil fractions. In addition the unconverted portions or fractions boiling above 1000 F. of the eflluents from either or both the maltene or asphaltene hydrogen treating steps can be passed to a coking operation. Also, if desired, blends of varying proportions of the two l000 F.+ fractions can be charged to a coking operation and by controlling the ratio of the l000 F.+ fractions the sulfur content of the coke produced can be varied over a wide range. Furthermore, the unconverted portion of the efiiuent from the hydrogen treatment of the asphaltene fraction can advantageously be employed as the charge to a visbreaking operation.

Our invention will now be described having reference to the attached drawing which shows a simplified flow diagram embodying our process.

An asphaltic containing residue boiling generally above about 1000 F. is introduced by means of line into contacting vessel 12 where it is contacted with pentane which is also introduced into contacting vessel 12 by means of line 14. The maltenes are dissolved in the pentane and the mixture of maltenes and pentane is removed from the top of the contacting vessel 12 by means of line 16 and passed to solvent separator 18 wherein the pentane is separated from the maltene fraction and removed from solvent separator 18 by means of line 20. The maltene fraction is removed from solvent separator 18 by means of line 22 and passed to reactor 24. Hydrogen is introduced into reactor 24 by means of line 26 and is contacted with the maltene fraction of line 22 in the presence of a supported hydrogenating catalyst contained in reactor 24. The hydrogen treated maltene fraction is then removed from reactor 24 by means of line 28 and introduced into fractionator 30. Hydrogen and gaseous hydrocarbons are removed from fractionator 30 by means of line 32 While one or more fractions boiling below about 1000 F. are removed from fractionator 30 as indicated by lines 34 and 36. A bottoms fraction boiling above about 1000 F. is also removed from fractionator 30 by means of line 38 which connects to both lines 40 and 42. By proper employment of valve 44 in line 40 and valve 46 in line 42 the 1000 F.+ bottoms fraction alternatively can be removed from the system via line 40 and recovered or can be recycled via lines 42 and 10 to contactor 12.

The asphaltene containing raffinate phase is removed from the bottom of contacting vessel 12 by means of line 48 and is passed to solvent separator 50. In solvent separator 50 any pentane entrained with the railinate phase is separated and removed by line 52. The asphaltene fraction is then removed from solvent separator 50 and passed by means of line 54 to reactor 56. Hydrogen is introduced into reactor 56 by means of line 58 and is contacted with the asphaltene fraction from line 54 in the presence of a supported hydrogenating catalyst contained in reactor 56. The hydrogen treated asphaltene fraction is then removed from reactor 56 by means of line 60 and passed to fractionator 62. Hydrogen and gaseous hydrocarbons are removed from fractionator 62 by means of line 64 while one or more fractions boiling below about 1000 F. are removed from fractionator 62 as indicated by lines 66 and 68. A bottoms fraction boiling above about 1000 F. is removed from fractionator 62 by means of line 70 which connects with lines 72 and 74. By proper employment of valve 76 in line 72 and valve 78 in line 74 the 1000 F.+ fraction of line 70 alternatively can be removed via line 72 and recovered or recycled via lines 74 and 10 to contactor 12.

As mentioned above, the hydrogen treated maltene bottoms fraction of line 38 can be either removed from the system for further treatment or recycled. Thus, by closing valve 44 in line 40 and opening valve 46 in line 42 the 1000 F,+ bottoms fraction of line 38 is recycled via lines 42 and 10 to contactor 12. In such situation the high boiling asphaltenes produced during the hydrogen treatment of the maltene fraction are separated from the uncoverted maltenes by passage through contactor 12 in the manner described above. The separated asphaltenes are then passed together with the asphaltene fraction of the fresh feed to the asphaltene hydrogen treatment operation conducted in reactor 56, while the unconverted maltenes together with the maltene fraction of the fresh feed are passed to the maltene hydrogen treatment operation conducted in reactor 24.

Similarly, by closing valve 76 in line 72 and opening valve 78 in line 74 the 1000" F.+ bottoms fraction of line 70 is recycled via lines 74 and 10 to contactor 12. In this situation the high boiling maltenes produced during the hydrogen treatment of the asphaltene fraction are separated from the unconverted asphaltenes and these maltenes are passed together with the maltene fraction of the fresh feed to the maltene hydrogen treatment operation of reactor 24 while the unconverted asphaltenes are returned for further hydrogen treatment in reactor 56.

Example I In this example a portion of a Kuwait vacuum residue having the inspections shown in Table I was subjected to solvent extraction with pentane at an average temperature of 350 F. and employing a solvent to oil ratio of 5 to l to yield an extract phase (maltenes) and a raffinate phase (asphaltenes). After removal of pentane solvent the asphaltene and maltene fractions had the inspection data also shown in Table I below.

TABLE I Vacuum Asphalresidue M altenes tenes Yield, percent by vol. of crude 22. 5 18. 2 4. 3 Gravity, API 6. 6 11. 4 Sulfur, percent by wt 5. 33 4. 48 7. 5 Carbon residue, percent by Wt 20. 11.4 46. 1 Insoluble in n-pentane, percent by wt 0. 29 92. 6 Vanadium, p.p.m 102.2 29.1 320 Nickel, p.p.m 29. 9 9. 4 72.

One portion of the vacuum residue and the asphaltene fraction were then separately subjected to comparatively mild hydrogen treatment at a temperature of 750 F., a pressure of 1000 p.s.i.g., a liquid hourly space velocity of 0.5 and a hydrogen feed rate of 10,000 s.c.f./b., in the presence of a catalyst comprising 0.5 percent by weight nickel, 1.0 percent by weight cobalt and 8.0 percent by weight molybdenum on an activated alumina. The yields obtained for each of these two runs are shown in Table II below.

TABLE II Asphal- Vacuum tenes residue Yields, percent by vol. of charge:

C1-C3 (percent by wt.) 2. 1 0.8 Gasoline (Ci-400 F.) 3.8 5.4 Furnace Oil (400 F.670 F.) 12. 6 10.9 Heavy Gas Oil (670 F.1,000 23.4 25. 9 Residue (1,000 F.+) 64.8 61. 7

In another set of comparative runs another portion of the vacuum residue and the maltene fraction were each separately subjected to comparatively severe hydrogen treatment at a temperature of 790 F., a pressure of 1000 p.s.i.g., a liquid hourly space velocity of 0.5 and a hydrogen feed rate of 10,000 s.c.f./b in the presence of the same kind of catalyst as described above. In Table III below is shown the overall conversion obtained by separate processing of the asphaltenes and maltenes in accordance with our invention as opposed to the conversion obtained when treating the vacuum residue at both the mild and severe temperatures employed for the separate treatment of the asphaltene and maltene fractions, i.e. 750 F. and 790 F., respectively.

by vol. of charge (100% by vol. boil 1,000 F.).

From the data in Table II above it will be seen that both the overall conversion obtained and the yield of distillate products is substantially the same when treating the asphaltene fraction and the total vacuum residue under the same mild conditions. Thus, it will be seen that substantially the same products in substantially the same yields are obtained when treating a. comparable volume of the asphaltene fraction separately, in accordance with our invention, as is obtained from the more traditional technique of treating the entire vacuum residue. This unexpected result takes on even further significance when considered in light of the data in Table III above wherein it is demonstrated that by the separate treatment of the asphaltene and maltene fractions at different temperatures in accordance with our invention the total conversion to lower boiling materials is greater than that obtained when treating the total vacuum residue as a single entity under either mild or severe conditions. Thus, as specifically demonstrated by the data in Table III the overall yield obtained in accordance with the process of our invention exceeds the yields obtained from treatment of the total vacuum residue by a quantity in the amount from about 10 to about 30 percent or more. It should be pointed out, however, that the two temperatures of 750 and 790 F. while being advantageous for the treatment of the asphaltenes and maltenes, respectively, would generally not be considered to be an optimum temperature to be employed for treatment of the total vacuum residue but rather a temperature above 750 F. and below 790 F. would most likely be selected, which would result in an overall conversion of the vacuum residue somewhat above 38.3 percent and below 65.4 percent.

Example II In order to provide a further basis of comparison, another Kuwait vacuum residue as well as a corresponding maltene fraction, the inspections for which are listed in Table IV below, were subjected to hydrogen treatment.

TABLE IV Vacuum residue Maltenes Gravity, API 5. 5 10. 5 Sulfur, percent by Wt 5. 45 4. 59 Carbon residue, percent by wt. 23. 11 13. 87 Insoluble in n-pentane, percent by Wt... 15.14 0.22 Vanadium, p.p.m 102 30. 8 Nickel, p.p.m 32 8.1

TABLE V Vacuum residue Maltenes Yields, percent by vol. of charge:

C1-C2 (percent by wt.) 2.6 2. 5 Gasoline (Ct-400 F.) I 12.0 13. 1 Furnace oil (400670 F.)... 20.8 28.4 Heavy gas oil (6701,000 F.) 36. 1 48. 0 Residue (1,000" F.+) 35. 2 16.3 Carbon, percent by wt. on catalyst. 12. 5 11. 1 Desuliurization, percent by wt. 88.4 98. 5

Total liquid product inspections Vanadium, p.p.m 20. 6 0.1 Nickel, p.p.m 10.6 0.2

An examination of the data shown in Table V above demonstrates that the yield distributions obtained by treating the total vacuum residue and separately treating the maltene fraction in accordance with our invention are noticeably superior for the separate maltene treatment. In this connection it will be noted that the quantity of more valuable lower boiling liquid hydrocarbons for each of the fractions of converted material is greater when the maltene fraction has been separately treated. Furthermore, it will be noted that the conversion obtained by the separate treatment of the mal-tene fraction in accordance with the selected operating conditions in accordance with our invention is substantially greater than obtained when start-up procedures well known in the art. By the time treating the total vacuum residue fraction. This is indithe start-up procedure had been completed and the selectcated by the fact that the amount of material boiling above ed operating conditions had been attained the reactor 1000" F. which remains unconverted in the treatment of had become plugged due to the build up of coke on the the total residue is more than twice as much as the 1000 catalyst and in the reactor.

F. unconverted material remaining from the separate This is a clear demonstration that the asphaltene fractreatment of the maltenes. It will also be noted that this t-ion cannot be treated under the same comparatively greater overall conversion and greater yield of the insevere conditions under which the maltene fraction is to dividual lower boiling fractions obtanied in accordance be treated in accordance with our invention. with our invention is accomplished at a somewhat lower rate of catalyst coking. Further comparison of the data Examp 16 IV shown in Table V clearly demonstrates that the process In this eXample comparative Tlms Were m d employof our invention, wherein the maltene fraction is treated g 88 Charge Stocks a maltfine fIEwt H btained from a separately, is substantially more effective in removing sul- Kuwait Vacuum residue and a heavy vacuum gas oil obfur than is the more traditional technique of treating the tained from 3 Kuwait Crude- Inspection datal' these entire vacuum residue. In fact, in excess of 10 percent Charge Stocks are ShOWHiH Table V el w.

more sulfur is removed in accordance with our invention.

Similarly, it will be noted that the overall liquid product TABLE VI obtained from the treatment of the total vacuum residue Heavy contains more than 200 times the amount of vanadium vacuu Malteno and more than 50 times the amount of nickel as was obgas on fmmn tained in the separate treatment of the mal-tene fraction GmVitY1API ViSCoSit SUS at F.: In accordance Wllh 01.11 lIlVeIltlOIl. 130 y,

Comparison of the data shown in Table V with the i g -sdata shown in Tables II and III clearly demonstrates sultunpcrc ent; iERQ tIIIIIIIII Nitrogen percent by wt that the process of our invention not only provides an Carbon rgsiduepementby wt overall increase in conversion over that obtainable when Aniline point, F treating the total vacuum residue as an entity but does Insolublem n'penmneypment by Carbon, percent by wt so with a significant increase in the quantity of individual Hydrogen, percent by wt product fractions obtained and without any loss in catalyst Vanadium N k 1, llfe due to coking. v a uii m distillation:

Example In 5 2??? 1::::::::::::::::: In this example a sample of the asphaltene fraction obggg tained in Example I, inspection data for which are shown 0% in Table I, was subjected to hydrogen treatment in the 58%;: II I presence of the same catalyst employed in Example I. The operating conditions selected for this example were the same as the conditions employed for the treatment 130th of these charge Stocks W treated in the Presence of the maltene fractions in Examples I and II and inof same catalyst comprising 6 p nickel, 20 P cluded a temperature of 790 F., a pressure of 1000 Cent tungsten and 2 PEYWnt fluorine 011 a ccmmefcial p s i g a liquid hourly Space velocity of 05 and a hydro silica-alumina carrier under varying conditions of tempergen feed rate of 10,000 s.c.f./b. The run of this example aml'e, Pressure and Space velocity- The Pmticular P was commenced at a low temperature which was then g COIIditiOnS employed in each of 1116 runs togfithel With gradually increased over a short period of time to obtain yield data are shown in Table VII below.

TABLE VII Run Number 1 2 3 4 5 6 7 8 9 ge Heavy vacuum gas oil Operating conditions:

Temperature, F 700 750 750 750 750 800 850 850 800 Pressure, p.s.i.g-. 1, 000 2, 000 2, 000 2, 000 2, 000 2, 000 2, 000 Space velocity, vol./hr./v0l. 1.0 1 .0 4.0 1 .0 Hydrogen feed rate, s.c.f./b 10, 000- 40, 000 Yields:

C 0 percent by wt 0 0.8 0 .5 0.3 1 04, percent by vol. 0.8 2 .9 1.4 1 .6 4. C5 0 .7 2 .8 1.6 0 .7 3 C5-350 F 350400 F.

Furnace oil/gasoline ratios: 350675 F./O5350 F 400675 F./C -400 F Conversion, percent by vol. by vol. 675 r ..1 17's 46 .s 16.2 20.8 73 .3 94.5 1'00 61' .5 9s .a

Run Number 10 11 12 13 14 15 16 17 18 Charge Maltenes Operating conditions:

Temperature, F 800 850 800 800 800 800 800 800 800 Pressure, p.s.i.g 2, 000 2, 000 2, 000 2, 000 2, 000 2, 000 3, 500 1, 000 500 Space velocity, vol./hr./vol 1.0 1.0 0.99 1.92 0 .46 0.95 0 .92 1 .00 0 .81 Hydrogen feed rate, s.c.t./b 10, 000

Run Number 1 2 3 4 5 6 7 8 9 Yields:

C4-C3, percent by wt 2.9 9 .7 3 .7 2.7 4.6 4.1 3.1 3 .9 6 .1 04, percent by vol. 1.5 3.9 2.2 1 .9 2.4 2.0 1.4 2.2 3 .0 C 1.4 4.3 1.9 2.0 2.0 1.6 1.8 2.1 2.2 14.6 34.9 13 .4 7 .5 15 .2 12.5 12.4 9 .9 10.0 5 .9 10.7 5 .4 4.2 8 .4 5.9 6 .2 7.8 4 .5 .5 45.6 18 .8 11 .7 23 .6 18 .4 18 .6 17 .7 14 .5 37 .4 50 .0 37 .0 24 .4 54 .1 39 .0 .8 38 .7 40 .9 17 .6 3 .7 F. 28 .5 1 .8 675 F.+ 46.1 5.5 45.7 63 .3 23.7 43 .4 47.3 42.8 42.4 Furnace oil/gasoline ratios:

350675 F./C -350 F-. 2.70 1 .55 2.77 3.01 3 .63 3 .18 2.96 3.87 3 .72 400675 F./C540O F 1 .71 1.01 1 .79 1.78 2.11 1.95 1.75 1 .95 2 .45 Conversion, percent by vol. 100% by vol. 675 F- 54.0 94.5 54 .3 36 .7 76.3 56.6 52.7 57.2 57.6

From Runs 10 through 18 in Table VII above it will be noted that maltene fractions can be treated in accordance with our invention so as to provide conversions to materials boiling below 675 F. from about 35 percent up to about 90 percent and above. While variations in temperature and space velocity understandably result in variations in conversion, it will be noted, as particularly illustrated by Runs 15 through 18, that variations in pressure appear to have no susbtantial effect on overall conversion. This is in marked contrast to the results obtained in treatment of a heavy vacuum gas oil as illustrated in Runs 1 through 9 wherein it is shown, such as, for example, in Runs 2 and 3, that a variation in pressure has a very marked effect upon conversion.

Furthermore, comparison of the furnace oil to gasoline ratios and the corresponding conversions obtained when treating the heavy vacuum gas oil of Runs 1 through 9 with the corresponding data obtained in Runs 10 through 18 illustrates that as a general rule the furnace oil to gasoline ratio obtained in the treatment of the heavy vacuum gas oil varies inversely with the conversions while when treating a maltene fraction in accordance with our invention there is no great variation in the furnace oil to gasoline ratio in the product obtained until the extremes of our operating ranges are approached. Thus, while furnace oil to gasoline ratios of about 4 or greater were obtained in treatment of the heavy gas oil as illustrated by Runs 1, 3 and 4, it will be noted that the conversions obtained in those same runs were about 20 percent or less. As the conversions in the treatment of the heavy vacuum gas oil are increased the furnace oil to gasoline ratio decreases sharply, thus, for example, while obtaining a conversion of 73.3 percent in the treatment of the heavy gas oil in Run No. 5 a furnace oil to gasoline ratio of a little bit better than 1 was obtained. In contrast to this a furnace oil to gasoline ratio of greater than 2 was obtained in Run No. 14 in accordance with our invention at a conversion of 76.3 percent. Even in an operation of higher severity as illustrated by Run No. 11 wherein a conversion of 94.5 percent was obtained a furnace oil to gasoline ratio of about 1 was also obtained. When achieving the comparable conversion in the treatment of the heavy vacuum gas oil as illustrated in Run No. 6 it will be noted that the ratio of furnace oil to gasoline was only 0.29.

While the conversions for all runs in Table VII above are expressed as percent by volume of product boiling below 675 F., it must be pointed out that such is not an accurate expression of real conversion obtained when treating the maltene fractions in accordance with our invention inasmuch as the maltene fraction charge stock boils substantially entirely above 1000 F., thus indicating that real conversions are in the range from about 80 to 90 percent or even higher. The purpose of computing conversions as percent by volume to material boiling below 675 F. was to provide a comparison of conversion and product distributions obtained by treatment of maltene fractions in accordance with our invention as opposed to the conversions and product distributions obtained when treating a heavy vacuum gas oil, a material boiling substantially completely below the maltene fractions treated in accordance with our invention. A comparison of the furnace oil yields of Runs 1 through 9 with the furnace oil yields of Runs 10 through 18 quite surprisingly demonstrates that approximately similar quantities of furnace oil are obtained by the treatment of the extremely high boiling maltene fractions in accordance with our invention as are obtained from the comparatively low boiling gas oil charge stock employed in Runs 1 through 9. Thus, it is extremely interesting to note that the treatment of the maltene fractions illustrated by Runs 10 through 18 not only produced substantially the same quantity of furnace oil as obtained in the heavy vacuum gas oil treatment of Runs 1 through 9 but also produced an additional quantity of materials boiling in the range from about 675 F. to about 1000 F., the boiling range of the charge stock employed in Runs 1 through 9. Thus, it could be stated that the separate treatment .of a maltene fraction in accordance with our invention produces a 675- 1000 F. fraction available for hydrocracking in the man her in which a heavy vacuum gas oil is hydrocracked while at the same time yielding a quantity of furnace oil comparable to that which would be anticipated from the hydrocracking of the 675-1000 F. or heavy vacuum gas oil fraction.

To illustrate the production of asphaltenes during the treatment of maltenes in accordance with our invention the 675 F.+ fraction obtained from Run 12 shown in Table VII was subjected to vacuum distillation and the various fractions subjected to analysis. The proportions of the various fractions, based on initial charge stock, together with the analysis of the 1000 F.+ fraction are shown in Table VIII below:

TABLE VIII Yields-percent by vol. of charge:

675-725 F. 4.2 725-1000 F. heavy gas oil 28.2 1000 F.+ residue 13.2 1000 F.+ residue:

Gravity, API 2.3 Viscosity, SUV, sec. 210 F. 4691 Carbon residue, percent by wt. 27.6 Insoluble in n-pentane, percent by wt 36.9 Vanadium, p.p.m. 2.3 Nickel, p.p.m. 3.8

Of particular significance among the data shown above is the quantity of materials insoluble in n-pentane in the 1000 F.+ residue as shown in Table VIII. This pentane insoluble material, which by definition comprises asphaltenes, is 36.9 percent by weight of the 1000 F.+ fraction. Referring to the data shown in Table VI it will be noted that the maltene fraction employed as charge stock contained only 1.14 percent by weight of materials insoluble in n-pentane. This conclusively demonstrates that there is a many-fold increase in asphaltene content eifected by a treatment of a maltene fraction in accordance with our invention.

1 1 Example V In this example several samples of the asphaltene fraction obtained in Example I, inspection data for which are shown in Table I, were subjected to hydrogen treatment in the presence of the same catalyst employed in Example I. The particular operating conditions employed together with product yields are shown in Table IX below.

TABLE IX Run Number 1 2 3 Charge stock --ASphaltenes+Bcnzonc--) (20 to 80 wt. ratio) Operating conditions:

Temperature, F 790 790 820 Pressure, p.s.i.g..- 1, 000 2,000 2,000 Spa co velocity *0, *0. 5 *0. 5 Hydrogen feed rate, s.c.f./b 10,000 Yields, percent by vol. of charge:

C1-C3 (percent by wt.) 3. 4 7. 5 Gasoline (04-400 T.) 13. 1 12.4 Furnace oil (400600 F.) 18. 4 30. 3 Heavy gas oil (6701,000 29. 3 42. 1 Residue (1,000" F.+) 50. 5 26. 4

Space velocity based on asphaltenes only.

In the first run of this example an attempt was made to treat an asphaltene fraction under the same conditions employed to treat the maltene fractions in Examples I and II but in this run the asphaltene fraction was diluted with benzene in the proportion of 20 percent by weight of asphaltenes and 80 percent by weight benzene. The liquid hourly space velocity employed was 0.5 based upon the asphaltene fraction present. Typical start-up procedure as described in Example III was employed and the desired operating conditions (indicated in Table IX) were attained. While the employment of the benzene diluent in this operation permitted a somewhat greater lapse in time between initial contact of feed stock with catalyst and plugging of the reactor due to build-up of coke on the catalyst and in the reactor than was obtained in Example III there was not suificient time to record any significant data regarding this run.

In Run No. 2 the pressure was increased to 2000 pounds in an efiort to retard coke formation on the catalyst and the run was kept in operation and data recorded during the period from 8 to 40 hours. In Run No. 3 when the temperature was increased 30 F. to 820 F., there was a substantial increase in conversion but the rate of coke build-up the reactor was also substantially increased to the extent that any further increase in severity of operation would have been impossible. At a hydrogen partial pressure of 3000 p.s.i.g, however, a temperature of 850 F. can be employed with a similarly diluted asphaltene fraction before the rate of coking prohibits operation.

Example VI Another sample of the same asphaltene fraction employed in Example I was diluted with a full range pretreated South Louisiana furnace oil in the proportion of 80 percent by weight asphaltenes and 20 percent by weight furnace oil and subjected to hydrogen treatment employing the same catalyst and the same operating conditions employed for treatment of the asphaltene fraction in Example I. The conditions employed and the yield obtained in this run are shown in Table X below. For ease of comparison the corresponding data obtained in the treatment of the undiluted asphaltene fraction in Example I are also set forth in Table X. In this Table X the space velocities, yields and percents desulfurization are based upon the asphaltene charge alone and not total liquid feed.

The data shown in Table X above demonstrate another advantage to be obtained in accordance with the embodiment of our invention wherein the asphaltene fraction is subjected to hydrogen treatment in the presence of a diluent. Thus, it will be noted that the conversion of asphaltcnes obtained when treating the diluted asphaltene fraction is substantially the same as that obtained when treating an undiluted fraction as represented by the unconverted l000 F.+ residue. Similarly, it will be noted that there was no diiference in the quantity of gaseous materials produced. On the other hand, however, it will be seen that a substantial increase in the quantity of the more valuable gasoline and furnace oil range products are obtained. Most significantly, however, is the fact that treatment of the diluted asphaltene fraction provided a desulfurization of 73.6 percent as opposed to only 57.8 percent with the undiluted fraction, thereby demonstrating that the employment of a diluent is effective to increase the desulfurization effect of our invention by more than 25 percent over that obtained when treating an undiluted fraction. As demonstrated by the data in Table X this phenomenon permits production of substantially the same quantity of lower boiling materials, and even an increase in the more valuable lower boiling products, all of which lower boiling products are of substantially reduced sulfur content.

We claim:

1. A process for the hydrogen treatment of asphaltic containing heavy hydrocarbons boiling above about 900 P. which comprises separating the hydrocarbons into an asphaltene fraction and a maltene fraction, separately subjecting the asphaltene fraction to hydrogen treatment under comparatively mild conditions including a temperature from about 600 F. to about 850 F. a pressure from about 500 to about 3000 p.s.i.g, a liquid hourly space velocity from about 0.1 to about 5.0 volumes of asphaltene fraction per hour per volume of catalyst and a hydrogen feed rate from about 2000 to about 20,000 s.c.f./b. of asphaltene fraction in the presence of a catalyst comprising a hydrogenating component selected from the group consisting of Group VI and Group VIII metals, their oxides and their sulfides composited with a refractory metal oxide carrier thereby producing a hydrogen treated asphaltene fraction boiling both above and below about 1000 F., separating the hydrogen treated asphaltene fraction into at least one fraction boiling below about 1000" F. and a fraction boiling above about 1000 F., recovering the at least one fraction boiling below about 1000 F. from the hydrogen treated asphaltene fraction, separately subjecting the maltene fraction to hydrogen treatment at a temperature in the range from about 750 to about 900 F. and at least 25 F. higher than the temperature employed in the treatment of the asphaltene fraction, a. pressure from about 500 to about 4000 p.s.i.g, a liquid hourly space velocity from about 0.2 to about 10.0 volumes of maltene fraction per hour per volume of catalyst and a hydrogen feed rate from about 2000 to about 20,000 s.c.f./b. of maltene fraction in the presence of a catalyst comprising a hydrogenating component selected from the group consisting of Group VI and Group VIII metals, their oxides and their sulfides composited with a refractory metal oxide carrier thereby producing a hydrogen treated maltene fraction boiling both above and below about 1000 F., separating the hydrogen treated maltene fraction into at least one fraction boiling below about 1000 F. and a fraction boiling above about 1000 F. and recovering the at least one fraction boiling below about 1000 F. from the hydrogen treated maltene fraction.

2. The process of claim 1 wherein the operating conditions employed in the treatment of the asphaltene fraction include a temperature from about 600 F. to about 775 F.

3. The process of claim 1 which further includes blending the asphaltene fraction with a hydrocarbon diluent boiling at least 300 F. below the boiling range of the asphaltene fraction prior to subjecting the asphaltene frac tion to hydrogen treatment.

4. The process of claim 3 wherein the operating conditions employed in the hydrogen treatment of the asphaltene fraction include a temperature in the range from about 775 F. to about 850 F. and a pressure from about 2000 to about 3000 p.s.i.g.

5. The process of claim 1 wherein at least a portion of the fraction boiling above about 1000 F. obtained from the hydrogen treated maltene fraction is recycled to the separation step.

6. The process of claim 1 wherein at least a portion of the fraction boiling above about 1000 F. obtained from the hydrogen treated asphaltene fraction is recycled to the separation step.

7. The process of claim 1 wherein at least a portion of the fraction boiling above about 1000 F. obtained from the hydrogen treated maltene fraction is subjected to a coking operation.

8. The process of claim 1 wherein at least a portion of the fraction boiling above about 1000 F. obtained from the hydrogen treated asphaltene fraction is subjected to a coking operation.

9. The process of claim 1 wherein the temperature employed in the treatment of the maltene fraction is at least about F. higher than the temperature employed in the treatment of the asphaltene fraction.

10. The process of claim 3 wherein at least a portion of the fraction boiling above about 1000" F. obtained from the hydrogen treated maltene fraction is recycled to the separation step.

11. The process of claim 3 wherein at least a portion of the fraction boiling above about 1000 F. obtained from the hydrogen treated asphaltene fraction is recycled to the separation step.

References Cited UNITED STATES PATENTS 2/1961 Pevere et al. 208-86 8/ 1960 Inwood 208211 US. Cl. X.R. 20889, 211

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,444,073 May 13, 1969 Harold Beuther et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, in the Table, line 57, "C -C should read C C Column 11, Table IX, column 3, "C -C (percent by wt.) 7 5" should read C C (percent by wt.) 5 7 Signed and sealed this 12th day of May 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR.