US2905606A - Conversion of hydrocarbons in the presence of neutron irradiation and a hydrogenation catalyst - Google Patents

Description

Sept. 22, 1959 R 5, LONG ETAL CONVERSION OF HYDROCARBONS IN THE PRESENCE OF NEUTRON IRRADIATION AND A HYDROGENATION CATALYST Filed April 8, 1957 HYDROCARBON FEED t F 4| Jr PRODUCT m w G t 5% m HunHHHHHI I I I MHHHHHIHUNH H w t H i u l? N W I W m 7 H 4 W W M N m w 2 l t N MT S 7 M Y I til E L II lllll I L G M h q 1| m A 9 D C Y H...

RObGHJBHIBOI'II IQ Henry i s mcm John P Longwell Inventors Robert W Houston By AZ Q.M Attorney 2,905,605 Patented Sept. 22, 11959 CONVERSION OF HYDROCARBONS IN THE PRES- ENCE OF NEUTRON IRRADIATION AND A HY- DROGENATION CATALYST Robert B. Long, Wanamassa, Henry J. Hibshman, Plainfield, and John P. Longweil, Westfield, N..l., and Robert W. Houston, Swarthmore, Pa, assignors to Esso Research and Engineering Company, a corporation of Delaware Application April 8, 1957, Serial No. 651,319

6 Claims. (Cl. 204-154) This invention relates to the radiolysis of hydrocarbons and is more particularly concerned with the conversion of petroleum hydrocarbons by neutron irradiation in the presence of a hydrogenation catalyst.

This application is a continuation-in-part of Serial No. 657,098, Preparation of Lubricating Oils by Irradiation, filed February 23, 1956, by the present inventors, and now abandoned, and of Serial No. 547,860, Hydrocarbon Conversion Process, filed November 18, 1955, also by the present inventors, and now abandoned.

In brief compass, this invention proposes a process wherein hydrocarbons are converted in a reaction zone by neutron irradiation in the presence of a significant amount of a hydrogenation catalyst at a temperature below 700 R, which is below the temperature range where the catalyst would have any appreciable effect on the reaction in the absence of radiation. A surprisingly saturated liquid product, as expressed by bromine number, is obtained in good yields.

It has now been found that when a hydrocarbon conversion reaction is carried out at moderate or low temperatures in the presence of a hydrogenation catalyst, unexpected results are obtained. While a reaction in the nature of hydrogen cleavage occurs, auto-hydrogenation takes place and the reaction products are largely saturated. As a result, the effects of conventional hydrogenating or hydrocracking of hydrocarbons can be obtained by the process of this invention while using no or minimal amounts, i.e., less than 100 standard cubic feet per barrel (s.c.f./bbl.), of extraneous hydrogen. More gasoline boiling range product, having a high octane number, is obtained and less polymer is formed when reforming reactions are carried out. The tendency of the hydrocarbons to polymerize or decompose into low molecular weight gases after being formed into radicals, is unexpectedly inhibited by the catalyst.

It has also surprisingly been found that during the irradiation of hydrocarbons in the presence of hydrogena tion catalysts, the catalysts exert an appreciable influence on the selectivity of the reaction, even when the reaction temperature is relatively moderate, i.e., the temperature is substantially below incipient thermal cracking or conversion temperatures.

The lighter liquid products of this invention are especially useful in or as gasolines. In a preferred embodiment, the C 430 F. boiling range product has an octane number above 90 Research Leaded (3 cc.). By C is meant hydrocarbons having 5 carbon atoms, the lowest boiling of which has a boiling point of 82 F. The heavier liquid products are useful in or as lubricants.

This invention is applicable to a wide range of gaseous and distillate hydrocarbon feed stocks boiling up to about 1150 F., including distillates derived from conventional petroleum oils, shale oils, tar sand oils, asphalts, synthetic oils, natural and artificial hydrocarbon gases, etc. It has the greatest use in the conversion of petroleum derived oils such as whole crudes, distillate, extracts or concentrates therefrom, or mixtures thereof. A particularly preferred feed stock is a gas oil, especially a paraffinic one, boiling in the range of about 400 to 700 F.

By hydrogenation catalyst is meant one comprising a base material or carrier, which is preferably highly porous, and has as an active ingredient, a minor amount, i.e., less than 20 wt. percent on catalyst, of a hydrogenation component. Conventional hydrogenation catalyst bases known in the art can be used. These comprise, for example, dried hydrous oxides such as alumina, silica, zirconia, titania, and the like, and mixtures thereof. Other carriers such as activated carbon, kieselguhr, etc. can, of course, be used. The carrier material can be derived from natural sources such as from bauxite, or can be manufactured, e.g., by precipitating alumina from an alcoholate alumina or from an aluminum sulfate solution. It is preferred that the base material have a high surface area, i.e., an area above 50 square meters per gram (m. /gr.). This surface area and other desired properties can be incorporated into the carrier by heat treatment, e.g., calcination; chemical treatment, e.g., acid treatment or chlorine treatment; and similar methods known to the art. The active components in some in stances can be incorporated into or onto the base during manufacture of the base.

The hydrogenation component used is preferably a metal, oxide, sulfide or salt of a group VI or VIII element. Specific preferred elements are nickel, cobalt, platinum, palladium, molybdenum, tungsten and mixtures thereof. Other known hydrogenation components can be such as copper, silver and zinc. The base material can be impregnated With a catalytic component or mixture thereof by known methods, such as by precipitation or mixing with a salt solution and drying. Preferred catalysts comprise an essentially pure alumina base and 0.01 to 2.0 Wt. percent platinum, and an essentially pure alumina base and 1 to 15 wt. percent of molybdena.

The catalyst used preferably has a particle size under about 1000 microns, but can be much larger in size if desired, e.g., one inch or more. Pellets or compactions can be used. The surface area of the catalyst is above 50 m. /gr. and usually does not exceed 600 mF/grz, the true density is in the range of 2 to 4 gr./cc., and the pore size is in the range of 20 to 150 A. The catalyst can exist as discrete particles or can be in the form of compactions or pellets.

The catalytic and carrier materials used are normally those which, upon neutron bombardment, produce radioisotopes having short half lives, i.e., less than 10 weeks and preferably less than one week, or have small neutron capture cross-sections so that very little of the material becomes radioactive. Preferably, the fraction of any given element (wt. percent on catalyst) times its capture cross-section, for neutrons having an energy in the range of 0.03 to electron volts (e.v.), is less than one barn.

The catalyst can be used as a suspension in the hydrocarbon reactant, or as fixed, fluid, or gravitating beds, all of which methods are known in the art. The catalyst, if contaminated, as by carbon deposition, can be regenerated by known methods such as burning, acid treating, chemical reworking and the like. The solids can be regenerated in place or external of the reactor, and either continuously or periodically, as the need arises.

This invention is based in part upon the important finding that hydrogenation catalysts surprisingly display an appreciable effect on selectivity at moderate temperatures, i.e., at temperatures below 700 F. This means that it is now possible to operate at lower temperatures, heretofore unattractive because of the slowness of the reaction rate, and this permits the obtainance of reactions and selectivities not previously possible. Of prime interest is'that undesirable secondary reactions can be avoided.

This invention is applicable to conversion reactions wherein the reactants are wholly or partly in the gas, liquid, or solid phase. It is most advantageously used with liquid phase reactions and the pressure used is, therefore, preferably sufiicient to maintain substantially liquid phase conditions.

It has been found that even during the cracking of what have customarily been thought of as hydrogen-- deficient materials, the lighter cracked products obtained are relatively highly saturated. The present invention can, therefore, secure operation equivalent to hydrogenation operations without the use of, or with very limited amounts of extraneous hydrogen. While it is preferred to utilize the advantages of this invention by operating at pressures below 15 atmospheres (atm.), higher pressures, e.g., up to 1000 atm. or greater, with or without the use of small amounts, i.e., less than 100 s.c.f./bbl. of extraneous hydrogen, will favor saturation of the product fractions. The total liquid product obtained has a bromine number below 20, which indicates that it is highly saturated. Expressed somewhat diiferently, the olefin/paraffin ratio of the C product is less than 0.3.

The process of this invention can most conveniently be carried out, particularly on a commercial scale, by employing a nuclear reactor and can be carried out either on a batch or a continuous basis. The present process is preferably carried out with some type of agitation or continuous flow, so that there is sufficient contact between the oil, the radiation, and the subdivided catalytic solids. To carry out a continuous process, the material to be irradiated can be simply pumped through the pile itself, or through pipes disposed in the pile. In some instances, the hydrocarbon reactant can also serve as a moderator for the nuclear reactor.

The drawing attached to and forming a part of this specification schematically illustrates this invention.

In the drawing, a hydrocarbon material, e.g., a distillate virgin naphtha, is introduced into the process by line 1. A hydroforming catalyst, e.g., alumina impregnated with platinum, supplied by line 2 from source 3, is mixed with the feed material. The preferred catalyst to oil ratio is in the range of 0.1 to 2.0. As shown here, hydrogen supplied by line 4 from reservoir 5 is admixed with the hydrocarbon feed, although its use in many cases is not necessary. The resulting mixture is then passed through irradiation source 6. The preferred feed rate is in the range of 36 to 3600 liquid volumes of feed per hour per volume of catalyst-free space (v./v./hr.), to obtain an average linear flow rate in the range of 0.01 to 1.0 feet per second (ft./sec.).

The radiation from the atomic pile consists primarily of neutrons and gamma rays. The results of this invention are dependent on neutron irradiation, probably because of the propensity of neutrons to favor C H bond cleavages over CC bond cleavages. Other types of radiation do not give equivalent results. The neutron flux used is preferably above about neutrons per square centimeter per second (n/cm. /sec.), and the associated gamma ray dosage is above about 10 roentgens perhour (R./hr.). Usually the neutron flux need not be above 10 n/cm. /sec., and the associated gamma dosage need not be above 10 R./hr. The present process is most effectively carried out employing fast neutrons, i.e. neutronshaving an energy above 30 e.v. Preferably the majority of the neutrons are fast neutrons. It is'also preferred that-of the energy absorbed by the hydrocarbon, at least 75% is derived from the neutrons. Th otal. dose... for. ll. type of diation rece y e feed, will vary somewhat with the feed, conditions, desired product, etc., but is preferably in the range of 0.3 to 3000 B.t.u.s/lb. of fresh feed. The irradiation temperature is below 700 F., and is usually above 50 F.

Although a suspensoid system is shown in the drawing, i.e., the solids are carried by the hydrocarbon reactant through the reaction zone, the catalyst can exist as fixed, fluid, or gravitating beds within the radiation zone 6. With fluid beds, the pipes carrying the reactant through the atomic pile are preferably vertical with upflow of the fluid reactant.

The irradiated material is transferred by line 7 to separation zone 8. The separation zone comprises means for recovering the catalyst such as by distillation, filtration, and absorption. The recovered catalyst. can be directly recycled, if desired, by line 9 or can be first treated as by burning, steaming, and-the like, to remove contaminates and/ or improve its properties before being recycled.

The hydrocarbon products and unused hydrogen, if any, are also separated in zone 8'. Thus distillation, extraction, or absorption, as with molecular sieves, can be used. If desired, the hydrogen and/or some of the hydrocarbon product can be recycled byline 10.

Separation zone 6 can also include means for removing and/or neutralizing radioactive waste products. Such means can include storage tanks to permit decay of radioactivity, ion exchange apparatus, distillation columns, and solvent extraction units. The finished product is removed from the process by line 11.

The conversion of feed, expressed as material converted out of the feed boiling range, is above 10%. The selectivity to normally liquid product obtained is high, being above wt. percent, based on feed boiling in the range of 400 to 1150 F. As previously indicated, the liquid product is surprisingly saturated.

The following examples serve to further illustrate this invention.

The air cooled, natural uranium, graphite moderated research reactor of the Brookhaven National Laboratories was used for these tests. This pile was operating at a total power of about 24 megawatts at the time, which gave the following flux distribution at the point where the oils were irradiated:

Slow neutron flux (.03 e.v.)=2.5 10 n/cm. /sec.

Fast neutron flux 30 e.v.)=0.7 10 n/crn. /sec.

Fast neutron flux 1 m.e.v.)=0.5 10 n/cm. /sec. Gamma dosage =1.7 10 R./hr.

The core of the reactor was approximately a 20 ft. x 20 ft. x 20 ft. lattice of graphite with horizontal oneinch diameter aluminum-clad uranium rods spaced evenly throughout the reactor extending from the north to south faces of the core. This core was completely surrounded by 5 ft; of concrete shielding. The sample holes used for irradiation were horizontal 4-inch x 4-inch square holes extending through the 5 ft. concrete shield and into the carbon core for adistance of 10 ft. from the core face. Normal operating temperatures in the experimental hole were from 250 to 400 F.

Three one-quart samples were irradiated at one time by placing them in three 3-inch diameter aluminum containers which were mounted on a horizontal aluminum sled. Vents of aluminum tubing extended from the vapor space of the containers out of the core and through the shielding to a sample receiver system where gases and condensable liquids were metered and collected. The samples were prepared by adding the solids to the container to fill it, evacuating the void space in the container, and sucking the oil into the container with a vacuum. The samples were then purged with purified nitrogen and inserted in the pile during scheduled shutdowns. After irradiation for ten days, they were withdrawn from the pile during shutdown.

2,905,608 5 6 Three oils were treated: 31.1 API gravity, a bromine number of 2.47 centigrams Oil A.il A was a narrow boiling virgin gas oil disper gram, 33.0 SSU viscosity at 210 F., viscosity index tilled from paraflinic South Louisiana crude. It had of 67, and a 0.14 wt. percent sulfur content.

a 307 API gravity, bromine numper of 1.25 centigrams Oil B had the following distillation characteristics: per gram; 34.4 SSU viscosity at 210 F., viscosity index of 67, and a 0.14 wt. percent sulfur content. Cuts Vol. percent Oil A had the following distillation characteristics: 3 3 6 F- 12.6 a 6 0/6 F. 85.1 Cuts Vol. percent 0 F. n;- 4.7 6Q0/70Q F 854 At atmospheric pressure. Above 700 F. 9.9

Oil B contained about 36% naphthenes, about 12% paralfins' and about 52% aromatics by volume.

A At atmospheric pressure. v

Oil A contained about 55% naphthenes, about para- Oil C.--Pure cetane (n-hexadecane).

fiin and about of aromatics b volume. 10 The results of these ex enrnents are iven in Table I. i g

011 B.O1l B was a narrow bolling naphthemc V1I- For comparison, runs made 1n the absence of a catalyst gm gas oil dlstilled from West Texas crude. It had a are included.

Table I Run 1 2 3 4 5 6 Catalyst Yes N 0 Yes No Yes No Feed.. A A B B 1/1 l/l 1/1 Days irradiated. 10 10 10 10 10 Temperature, F- 330 150 295 150 330 260 Conversion to:

Gas, wt. percent on feed 19.0 3. 8 2. 6 4. 3 8.2 (A) 0 Olefin to paraflin, ratio in gas 0.1 1. 0 0. 3 1.1 0.02 O5 Isoto n-paraifin, ratio in gas- 0. 9 1. 0 1. 0 0.7 0.05 Naphtha:

Boiling range, "F 0/430 0/430 0/430 0/430 0/430 0/430 Percent on feed..- 2, 4 0.9 0 1. 8 19.8 Lamp sulfur, wt. percen 0.03 0. 04 0. 44 Vol. percent aromatics 5. 3 7. 8 10. 4 3. 0 Vol. percent o1cfins. 15. 5 39. 1 42. 7 3.0 Vol. percent saturates.-. 79. 2 53. 1 46. 9 94.0 Refractive Index 20 C..- 1. 4070 4322 1. 4338 1. 4073 Gravity, API 52. 5 51. 1 61. 5 Bromine No., cgsJcc 15.8 46.3 1.1 Calculated octane. N 0., research le (3 cc.) 93 Heating Oil:

Boiling range, "F 430/600 430/600 430/600 430/600 430/540 430/540 Percent on feed 6. 6 5.1 5.1 10.4 5. 1 1. Lamp sulfur, wt. percent 0. 02 0.04 0. 66 0. 95 0. 001 Vol. percent aromat1cs. 7. 8 8. 1 16. 9 19. 5 1.8 0.9 Vol. percent oleflns... 31. 1 52. 3 37. 3 37. 7 3. 6 30. 7 Vol. percent saturates-.- 61. 1 39. 6 45. 8 42. 8 94. 6 68. 4 Refractive Index 20 C. 1. 4413 1. 4651 1. 4728 1.4688 1 4271 1 4340 Gravity, API 38.0 35. 2 36. 0 35. 7 .7 Bromine No., cgs Ice 15. 1 11.0 25. 5 29. 9 1. 1 17. 7 Aniline pt., F 164 158 146 150 Diesel Index 62 56 52 54 Fee Boiling range, "F 600/700 600/700 600/700 600/700 540/560 540/500 Percent on feed 29. 3 32. 1 48. 0 39. 2 2 Lamp suliur, wt. percent 0. 04 0.09 0.98 1. 58 0. 0004 Vol. percent aromatics 1. 4 1. 0 Vol percent olefius- 2. 7 16.7 Vol percent saturates." 95. 9 82. 3 Refractive Index 20 .0 1. 4601 4886 1. 4321 1. 4401 Gravity, API 50. 9 29. 9 50. 3 49. 8 Bromine No., 13. 0 21. 7 0.4 9. 6 Aniline pt., "F 198 Diesel Index- 99 I High Boiling Fractions:

(1) Boiling range, "F 560/700 560/010 Percent on feed... 3. 3 1.9 Vol. percent aromatics 0.0 Vol. percent nlefina 13. 5 Vol. percent saturates 86.5 Refractive Index 20 0. 1. 4390 Gravity, APT 48. 5 Bromine No., cgsJ 10. 8 (2) Boiling range, F 610/700 Percent on feed--. 2. 7 Refractive Index 20 C. 1. 4493 Gravity, AP 44.0 Bromine No., cgsJ 24. 9 (3) Boiling range, F 808/900 735/900 700/900 700/900 700/900 700/900 Percent on feed 6. 0 5. 8 8. 6 1. 5 16. 3 5. 4 Relractive Index 20 C- 1. 4545 1. 4632 Gravity, AP 44. 0 41. 2 Bromine No., cgsJ 0. 9 Viscosity- SSU 210 F 54. 79 47. 49 53. 89 46. 79 37. 84 41.65 SSU 100 F 426. 8 250.0 389. 3 235. 4 76. 6 110. 7 Index 65 71 71 72 144 139 Pour point, F.-- 5 55 (4) Boiling range, F.. 900/990 900/975 900/1000 900/955 900/920 900/970 Percent on feed 9. 7 9. 7 16. 3 9. 8 1. 8 2. 8 Refractive Index 20 0 1. 4700 Gravity, "AP 38. 5 Bromine No., cgsJ 18. 9 Viscosity- SSU 210 F 106. 7 79. 32 G0. 88 50. 78 SSU 100 F 2, 081. 4 1, 305.1 571. 4 218. 5 Index 56 35 127 Four point, F -10 -5 -15 Footnote at end of table.

Table I-Continued Run 1 2 3 4 5 6 Bottoms: V r 5 i I i Boiling range, "F 990+ 975+ 1,012+ 955+ 920+ 970-]- Percent on feed 19. 0 38. 4 19. 6 24. 9 19.8 18. 0 Viscosity .ssU..@ 210. F 231. s SSU 100 F 2, 605.4 Index l38 Pour point, "13 80 0 (A): No gas samples taken. These data show a high degree of utilization of available 15 2. The process of claim 1 wherein said hydrogenation hydrogen, even at atmospheric pressure, for the paraffinic feed stocks. This process is similar to hydrocracking in productsexcept that hydrocracking does not take place at this temperature without catalyst or without radiation. It is to be noted that the hydrogenation catalyst increases the selectivity of conversion. toward lighter. products at the expense of polymers and helps to control product distribution. The relatively. slight eifect on the naphthenic feed is largely due to sulfur poisoning of the platinum catalyst with this high sulfur feed. The effectiveness of the catalyst in saturating products and increasingconversion to low boiling products lines up according to the sulfur contents of the feeds. Thus, sulfur resistant catalysts, e.g., catalyst containing molybdenum, would be needed with high sulfur feeds. It is apparent from these data that the products of this invention are useful as gasolines, diesel fuels, and lubricants.

Having described this invention, what is sought to be protected by Letters Patent is succinctly set forth in the following claims.

Whatfis claimed is:

l. A process comprising exposing a hydrocarbon boiling up to 1150 F. in the presence of a significant amount of a hydrogenation catalyst comprising a porous carrier impregnated with a minor but catalyzing amount of a hydrogenation component, said catalyst having a surface area above 50 m. /gr., and in the presence of under 100 s.c.f. of added hydrogen/bbl. of feed, to radiation comprising neutrons, at a neutron flux in the range of 10 to 10 n/cm. /sec., and at a temperature in the range of 50 to 700 F. until 0.3 to 3000 B.t.u.s of radiant energy per pound of fresh feed have been received and the conversion of said hydrocarbon is at least 10%, and recovering a liquid product inyields above 80 wt. percent, based on converted'feed, said liquid'product havinga bromine number below20.

catalyst consists of the dry hydrous oxides of a material selected from the group consisting of alumina, silica, zirconia, titania and mixtures thereof, impregnated with under 20 wt. percent of a hydrogenation compoiient'selected from the metals, oxides, sulfides, and salts of elements selected from the group consisting of nickel, cobalt, platinum, palladium, molybdenum, tungsten, and mixtures thereof. H

p 3. The process of claim l.wherein said hydrogenation catalyst. comprises an: essentially pure alumina base with 0;0l to 210 wt. percent of platinum distended thereon.

4.. The. processof; claim 1' wherein said liquid product is separated to recover a fraction boiling in the range .of 8'2-430 F., said fraction having a Research Leaded octane number above 90;.

5. The process of claim 1 wherein said irradiation also comprises gamma rays and is obtained from a nuclear reactor, andwherein at least 75% of the energy absorbed by said hydrocarbon is derived from neutrons.

6. The process of claim 1 wherein said hydrocarbon consists of'a paraifinic gas oil boiling in the range of about 400 to 700 F.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,627,938 Tingley May 10, 1927 2,350,330 Remy June 6, 1944 2,743,223 McClilltDIlEt al. Apr. 24, 1956 1 FOREIGN PATENTS 665,263 Great Britain Jan. 23, 1952 QTI-IER REFERENCES Charlesbyg lroc. Roy. Soc. (London), vol. 222A, pp. -74, February 23, 1954.

,, Mincher: A.E.C;., .KAPL-731, pp. 1-7, April 2, 1952.

Claims (1)

1. A PROCESS COMPRISING EXPOSING A HYDROCARBON BOILING UP TO 1150* F. IN THE PRESENCE OF A SIGNIFICANT AMOUNT OF A HYDROGENATION CATALYST COMPRISING A POROUS CARRIER IMPREGNATED WITH A MINOR BUT CATALYZING AMOUNT OF A HYDROGENATION COMPONENT, SAID CATALYST HAVING A SURFACE AREA ABOVE 50 M.2/GR., AND IN THE PRESENCE OF UNDER 100 S.C.F. OF ADDED HYDROGEN/BBL. OF FEED, TO RADIATION COMPRISING NEUTRONS, AT A NEUTRON FLUX IN THE RANGE OF 10**11 TO 10**15 N/CM.2/SEC., AND AT A TEMPERATURE IN THE RANGE OF 50* TO 7000* F. UNTIL 0.3 TO 3000 B.T.U.''S OF RADIANT ENERGY PER POUND OF FRESH FEED HAVE BEEN RECEIVED AND THE CONVERSION OF SAID HYDROCARBON IS AT LEAST 10%, AND RECOVERING A LIQUID PRODUCT IN YIELDS ABOVE 80 WT. PERCENT, BASED ON COVERRTED FEED, SAID LIQUID PRODUCT HAVING A BROMINE NUMBER BELOW 20.

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