US3119765A - Catalytic treatment of crude oils - Google Patents

Description

Jan. 28, 1964 H. G. CORNEIL ET AL CATALYTIC TREATMENT OF CRUDE OILS Filed Oct. 19, 1959COMPRESSOR 52 48 OFF-GAS REACTOR --REAOTOR l6 ,-SEPARATOR cglllni "3 24 32 as 42 4-5 |3 MPRE HEATER coouza nvonoseu 62 X 22DISTILLATION 36 34 zone K"BO INVENTORS.

HAMPTON G. CORNEIL, RICHARD S. MANNE, GEORGE R. L. SHEPHERD, ARMAND M. SOUBY ATTORNEY.

United States Patent Ofifice 3,119,765 Patented Jan. 28, 1964 3,119,765 CATALYTIC TREATMENT OF CRUDE OILS Hampton G. Corneil, Richard S. Manne, George R. L.

Shepherd, and Armand M. Souby, Baytown, Tex., as-

signors, by mesne assignments, to Essa Research and Engineering Company, Elizabeth, N.J., a corporation of Delaware Filed Oct. 19, 1959, Ser. No. 847,298 3 Claims. (Cl. 208-210) This invention relates to a method for the catalytic treatment of petroleum hydrocarbon crude oils.

More particularly, this invention relates to a catalytic hydrotreating process for the upgrading of hydrocarbon crude oils.

Petroleum hydrocarbon crude oils are comprised of a wide variety of components boiling over a wide range. Accordingly, it is the customary practice to fractionate the crude oil and to separately treat the various fractions that are obtained.

In accordance with the present invention, however, a method is provided wherein the crude oil is treated in a manner to convert selectively the higher boiling fractions thereof and in order to provide for a substantially desulfurized product.

Briefly, in accordance with the present invention, a petroleum hydrocarbon crude oil is passed upwardly through a fixed bed of a supported cobalt molybdate cata lyst in the presence of controlled amounts of added hydrogen in order to desulfurize partially the crude oil and in order to at least partially convert the heavier components of the crude oil. The total effluent is separated into a vapor phase fraction which is further treated with hydrogen in the presence of a supported cobalt molybdate catalyst in order to provide a substantially desulfurized product and a liquid phase which is preferably recycled.

The feed stocks for the present invention are petroleum hydrocarbon crude oils which contain residuum components such as total crudes, topped crudes, residua, etc. and which are further characterized by containing about 50 to 100 volume percent of components boiling above about 800 F.

The catalyst that is utilized in acordance with the present invention is a supported cobalt molybdate catalyst such as a catalyst comprising from about 5 to 20 weight percent of cobalt molybdate supported on a high surface area carrier such as synthetic gamma alumina, bauxite, etc.

The conversion conditions to be utilized in both the first and second stage include a pressure within the range of about 200 to 1000 p.s.i.g., a temperature within the range of about 700 to 800 F., a space velocity within the range of about 0.5 to 5 v./v./hr., and a hydrogen charge rate within the range of 700 to 7000 standard cubic feet of hydrogen per barrel of feed. The first stage reaction is conducted upflow, the second stage reaction being conducted either upflow or downflow, as desired.

The reaction conditions may be the same or different in the second stage as compared with the first stage within the above-described limits. Thus, the second stage may be operated at the same pressure or a lower pressure if not less than about 200 p.s.i.g.

Numerous advantages are obtained in accordance with the present invention. Thus, at least a portion of the residuum components of the crude oil (those boiling above about 1000 F.) are converted to lower boiling desulfurized products. When appropriate recycle operations are employed, substantially all of the residuum components may be thus converted. In addition a high yield of substantially sulfur-free heavy and light gas oil fractions are obtainable, together with a good yield of low sulfur naphtha fractions containing reduced quantities of olefins.

The invention will be further illustrated with reference to the accompanying drawing wherein the single figure is a schematic flow sheet illustrating a preferred form of the present invention.

Turning now to the drawing, there is shown afirst stage reactor 10 and asecond stage reactor 12. A bed of particulate supported cobalt molybdate such as gamma alumina supported cobalt molybdate is provided in each of thereactors 10 and 12.

A crude oil from any suitable source (not shown) may be charged by way of aline 14 to apreheater 16 wherein the charge is heated to reaction temperature. Make-up hydrogen from an extraneous source may be added to the crude in theline 14 by way of aline 18, recycle off-gas rich in hydrogen may be charged to thecrude line 14 by way of arecycle line 20, and heavy conversion components may be charged to theline 14 by way of a liquids recycle line 22.

The thus-prepared mixture of feed components is heated in thepreheater 16 to a desired conversion temperature and discharged from thence by way of acharge line 24 leading to the bottom of the firststage reaction zone 10. The feed mixture is passed upflow through thefirst stage reactor 10 under conversion conditions as above set forth. As a consequence, the liquid components of the feed stock are partially desulfurized and, in addition, partial conversion of heavier components of the feed stock occurs. The total efiiuent from thereaction zone 10 is discharged from the top thereof by way of adischarge line 26 leading to aseparator 28 wherein the total efliucnt is separated into a gas phase and a liquid phase. The gas phase, which will contain a substantial portion of the charge components, is charged to thesecond stage reactor 12 by way of aline 30 for further treatment under the above-described conversion conditions. As a consequence of the second stage, the sulfur content of thevapor phase fraction 30 is materially reduced and, in addition, olefins that may be present in the conversion products are at least partially saturated with hydrogen.

The liquid fraction from theseparator 28 is discharged by way of a bottoms draw-offline 32 controlled by a valve 34. All or a selected portion of the bottoms fraction may be discharged from the system for further treatment. However, in accordance with a preferred embodiment of the present invention, the liquid fraction is recycled by closing the valve 34 and by opening thevalve 36 in the above-mentioned recycle line 22.

The total efiluent from thesecond stage reactor 12 is discharged by aline 38 leading to a cooler 4-0 wherein liquefiable hydrocarbons are condensed. Fromcooler 40, the total efiiuent is charged by aline 42 to asecond separator 44. A gas phase consisting principally of hydrogen and containing normally gaseous hydrocarbons is taken overhead by way of a line 4-6. Normally, at least a portion of the off-gas will be discharged from the systern by adischarge line 48 controlled by avalve 50. All or a selected portion of the off-gas may be charged by way of aline 52 controlled by avalve 54 to acompressor 56 discharging into the above-describedrecycle line 20.

The liquid phase from thesecond separator 44 is discharged by way of aline 58 leading to further treating facilities. Thus, for example, the liquid fraction may be charged by way of aline 58 to adistillation column 60 wherein the liquid fraction may be separated into anaphtha fraction 62, akerosene fraction 64, a light gas oil fraction 66, a heavygas oil fraction 68, and aresiduum fraction 70.

The residuum fraction may be discharged from the system by opening thevalve 72 in thebottoms discharge line 70. Alternately, it may be returned by way of abranch line 74 controlled by avalve 76 to the recycle line 22.

Similarly, all of the heavy gas oil may be discharged from the system for further treatment (e.g., catalytic cracking) by opening thevalve 78 in the discharge line 63. Alternately, a valve 80 in arecycle line 82 leading to therecycle line 74 may be opened whereby at least a portion of the heavy gas oil may be returned to the recycle line 22.

The invention will be further illustrated by the following specific examples which are given by way of illustration and not intended as limitations on the scope of this invention.

EXAMPLE I In order to illustrate the necessity for operating the first stage in an upfiow phase, a crude oil is processed under superficially identical reaction conditions in two separate reactors, one reactor being operated on a downflow basis and the other being operated on an upfiow basis.

The composition of the feed stock is set forth in Table I, the reaction conditions employed and the results obtainable are set forth in Table II.

Table] INSPECTIONS ON CRUDE OIL CHARGED Gravity, API 25.9 Sulfur, wt. percent 2.70 Viscosity at 80 F., SSU 270 Viscosity at 100 F., SSU 195 Ash, p.p.m 94 ASTM distillation: 1

IBP, F 181 5% off at, "F 257 oil at, F 301 20% off at, F 398 30% off at, F 544 40% off at, 'F 647 60% off at, F 790 70% off at, "F 923 Duplicate ASTM D-S gas oil distillations to 600 F., followed by ASTM D-1160 10 mm. distillation on combined bottoms. Temperatures at 10 mm. converted to the equivalent temperatures at atmospheric pressure shown above by means of the chart onpage 42 of Maxwell, Data Book on Hydrocarbons, Von Nostrund (New York, 1950).

Table II FIRST'STAGE HYDRQDESULFURIZATION [800 p.s.i.g., 745 F. inlet, 0.9 v./v./hour, 1700 s.c.f. Ila/B] Type of Operation Crude Downflow Upflow Charged Overall Desullurization, Percent 67 63 Vol. Wt. V01. Wt. Distillation Fractions Per- Per- Per Percent 1 cent cent 1 cent C 375 F. Naphtha 18.1 0.03 17. 8 0.02 375-530 F. Kerosene 12.1 0.22 14.3 0. 04 530600 F. Light Gas Oil 5. 6 0. 75 7. 3 0.07 600-1,040 F. Gas Oil 33. 5 2.3 38.1 0.31 1,040 F.+Residuurn 30. 2 3. 8 22. 1 2. 9

Total 0 and Heavier 99. 5 2. 7 99. 6 0. 89

1 Based on original crude charged.

From Table II, it will be observed that there is a significant conversion of the 1040 F.+ residuum fraction in the upfiow reactor and that a much lesser conversion is obtained with respect to the downflow reactor. It will be noted, moreover, that although enhanced yields of kerosene and naphtha are obtained by the upfiow reaction conducted in accordance with the present invention, substantially the same quantities of heavy and light gas oil are obtained in both instances.

As is seen by the analysis of sulfur, however, the first stage reaction is not satisfactory from the point of sulfur removal in that significantly larger amounts of sulfur are present in the gas oil fractions from the upfiow reaction as compared with the sulfur removal obtained by the downflow reaction.

However, further treatment of the vapor phase from the first stage reaction here illustrated significantly reduces the sulfur content of the distillate materials.

EXAMPLE II In order to illustrate the effects obtainable by the two stage process of the present invention, a separate hydrocarbon feed stock is treated in stages.

The feed stock that is utilized is a West Texas vacuum ASTM distillation, percent off at 1040 F 9.0

l\l'.ethod of ASTM D-1160. but run at 1 mm. pressure instead of 10mm. Temperature converted to the equivalent at atmospheric pressure by means of the chart onpage 42 of Maxwell, Data Book on Hydrocarbons, Von Nostrand (New York, 1950).

Treat the above-identified feed stock in the presence of a commercial catalyst consisting of about 15 weight percent of cobalt molybdate supported on gamma alumina under upfiow conversion conditions including a pressure of about 800 p.s.i.g., an average reactor temperature of about 785 F., a space velocity of about 0.55 v./v./hr. and a hydrogen charge rate from about 2950 cubic feet of hydrogen per barrel. As a result of the first stage reaction, about 57 percent desulfurization is obtained and about 60 percent of the 1040 F.+ material is converted to lighter products.

Separately collect the vapor and liquid products from the first stage. The mol percent of each component or fraction in the total reactor product and the percentage of that component or fraction in the vapor phase at the reactor outlet are set forth in Table IV.

Table IV Percent Component vaporized Component Total Treat two portions of the vapor phase in accordance with the present invention in separate runs. Conduct one second-stage run at a pressure of about 400 p.s.i.g. and an average reaction temperature of about 766 F. Conduct the other second-stage higher pressure of 575 p.s.i.g. and a high reaction temperature of about 787 F.

The reaction conditions employed and the gross results obtained are set forth in Table V.

Table V HYDRODESULFURIZATION OF VAPOR PHASEFRACTION OF PRODUCT FROM HYDRODESULFURIZATION OF CRUDE RESIDUUM Run No., HDS 2002 2008 Pressure p.s.i.g 400 575 Avg. Catalyst Temp, 766 787 Feed Rate, v./v./hr. 2.0 1.9 Hz Rate, s.c.f./b 2,970 2, 870 Hz Consumption, s.c.f./b. 305 290 Percent Desulfurization 89 96 Liquid Product Yield, Vol. Percent of Feed 99. 6 95. 7

Feed

Inspections on Liquid Product:

Gravity, API 29. 4 30.9 31.0 Sulfur, Wt. Percent. 0.66 0.05 0.02 Distillation Data- IBP, F. 345 162 168 FBI, F 1,004 1,004 1,004 IBP-430 raction, Vol. Percent... 20. 2 23.0 23. 4 430-650 F. Fraction, Vol. Percent.-. 37.1 42. 4 44.9 650-1,004 F. Fraction, Vol. Percent. 42. 7 34. 6 31. 7

ZATION OF VAPOR PHASE PRODUCT FROM HYDRODE- SULFURIZATION OF CRUDE RESIDUUM Run No., HDS Feed 2002 2008 Naphtha Fraction HEP-430 F.):

Gravity, API 49. 3 47. 3 46. 8 Sulfur, Wt. Percent 0.07 0.01 0. 02 Res. Oct No (+1 cc. TEL) 68.3 64.0 66.6 Aromatics, Percent 23. 4 24. 6 26. 6 Bromine No., MgJgm 9. 7 2. 1 1. 5

Heating Oil Fraction (430650 F.

Gravity, API 30.1 30. 4 29.9 Sulfur, Wt. Percent 0.36 0.05 0.01 Aniline Point, F l- 124 129 Neut. Value, rug. KOH/gm. 0. 20 0.04 0.01 Aromatics, Percent 55. 6 55.0 56. 3 Phenol Content, Wt. Percent- 0. 10 0.01 0.01 Thiophenol Content, Wt. Perc 0. 006 0. 002 0.001 Bromine No., rug/gm 11.0 3.0 3.1

Table VI-Cont1nued Run No., HDS Feed 2002 2008 Gas Oil Fraction (6501,004 F.):

Gravity, API 19.1 21. 9 22. 3 Sulfur, \Vt. Percent-- 0. 83 0.07 0. 04 Nitrogen, Wt. Percent 0. 28 0.22 O. 20 Bromine No., mgJgm 13.1 9. 9 11.2 Conradson Carbon, Wt. Percent.- 10.2 0.73 0. 44 Refractive Index at 67 C., 7113 1. 5166 1. 5062 1. 5080 ASTM D-ll60 Distillation F 754 734 737 804 754 747 908 807 795 984 890 883 1, 047 968 Aromatic Rings, Wt.Percent 20. 9 19. 5 21.2

Having described our invention, what is claimed is:

1. A method which comprises the steps of passing a crude petroleum hydrocarbon feed stock containing at least about 50 volume percent of components boiling above about 800 F. in an upfiow direction through a first reaction zone containing a fixed bed of a supported cobalt moly bdate catalyst under conversion conditions including a temperature of 700 to 800 F. and a pressure of 200 to 1000' p.s.i.g. at a space velocity of about 0.5 to 5 volumes of feed stock per volume of catalyst per hour in the presence of 700 to 7000 cubic feet of hydrogen per barrel of feed stock, separating the total efiluent from said first reaction zone without substantial cooling thereof into a vaporized fraction and a liquid fraction, recycling at least a portion of liquid fraction to said first reaction zone, passing said vaporized fraction directly after said sep a-ration through a second reaction zone containing a fixed bed of supported cobalt molybdate catalyst under conversion conditions similar to those in the first reaction zone and recovering a desulfurized product from the effluent from said second reaction zone.

2. A method as in claim 1 wherein the effiuent from the second reaction zone is fractionated to separate cornponents boiling above about 800 F. from the remaining components of said eflluent, wherein the normally liquid components of said effluent boiling below 800 F. are recovered and wherein the components of said efiluent boiling above 800 F. are recycled to said first reaction zone.

3. A method as in claim 2 wherein a hydrogen containing normally gaseous off-gas product is recovered from the efiluent from said second reaction zone and wherein at least a portion of said oil-gas is recycled to said first reaction zone to provide at least a portion of the hydrogen.

References Cited in the file of this patent UNITED STATES PATENTS 2,771,401 Shepherd Nov. 20, 1956 2,902,436 Mills Sept. 1, 1959 2,909,476 Hemminger Oct. 20, 1959 2,914,462 Hemrninger Nov. 24, 1959 2,934,492 Hemminger et al Apr. 26, 1960

Claims (1)

1. A METHOD WHICH COMPRISES THE STEPS OF PASSING A CRUDE PETROLEUM HYDROCARBON FEED STOCK CONTAINING AT LEAST ABOUT 50 VOLUME PERCENT OF COMPONENTS BOILING ABOVE ABOUT 800*F. IN AN UPFLOW DIRECTION THROUGH A FIRST REACTION ZONE CONTAINING A FIXED BED OF A SUPPORTED COBALT MOLYBDATE CATALYST UNDER CONVERSION CONDITIONS INCLUDING A TEMPERATURE OF 700* TO 800*F. AND A PRESSURE OF 200 TO 1000 P.S.I.G AT A SPACE VELOCITY OF ABOUT 0.5 TO 5 VOLUMES OF FEED STOCK PER VOLUME OF CATALYST PER HOUR IN THE PRESENCE OF 700 TO 7000 CUBIC FEET OF HYDROGEN PER BARREL OF FEED STOCK, SEPARATING THE TOTAL EFFLUENT FROM SAID FIRST REACTION ZONE WITHOUT SUBSTANTIAL COOLING THEREOF INTO A VAPORIZED FRACTION AND A LIQUID FRACTION, RECYCLING AT LEAST A PORITON OF LIQUID FRACTION TO SAID FIRST REACTION ZONE, PASSING SAID VAPORIZED FRACTION DIRECTLY AFTER SAID SEPARATION THROUGH A SECOND REACTION ZONE CONTAINING A FIXED BED OF SUPPORTED COBALT MOLYBDATE CATALYST UNDER A CONVERSION CONDITIONS SIMILAR TO THOSE IN THE FIRST REACTION ZONE AND RECOVERING A DESULFURIZED PRODUCT FROM THE EFFLUENT FROM SAID SECOND REACTION ZONE.

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