US2682494A

US2682494A - Deasphalting process

Info

Publication number: US2682494A
Application number: US272429A
Authority: US
Inventors: Weikart John
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1952-02-19
Filing date: 1952-02-19
Publication date: 1954-06-29
Anticipated expiration: 1971-06-29

Description

June 29, 1954 J. wElKART 2,682,494

DEASPHALTING PRocEss Filed Feb. 19, 1952 GASES GO) .El

LT. LIAPHTHA 5C) 1- i 1 4 i5 N 5 l FEE@ HvY. NAPHTHA l f @i pzzoPAuE GAS OH.) g 7 @nomma QEDLJcLE/D 5 f 55- ,54

(hun E. i O (bf2 APHAur 5 lrL @Lemus 'Zona T Aem-mur P L5e 6 Asst? 25.2 f ,25 Ganan/nora.. FizAdTlouAToQ,- 'QYC''-Q*-l5\ l ZA REAc.T,o`rL UKLLEQJEUU 30 ZSLEIE l L J @ma L lllEcl ninxca- EE i" 1 \L T GMD 2? I: .l l 1| YE ^V s L- ji/ '29 K i? 55 y .oT'roh/l Am., @DENT '2 Mmm/5T 5i Mohn. miliari Qnvenbof CLUborne Patented June 29, 1954 2,682,494 DEASPHALTIN G PROCESS John Weikart, Westfield, N. J., assignor to Standard Oil Development Company, a corporation of Delaware Application February 19, 1952, seria1No.272,429

2 Claims.

The present invention is concerned with an improved process for the removal ofasphaltic constituents from residual oils whereby increased yields of higher quality lubricating oils and fuel oils are obtained. The present invention is also concerned with an improved process for the preparation of satisfactory feed stocks for fluid cracking operations, whereby higher quality hydrocarbon products boiling' in the gasoline and heating oil boiling ranges are obtained by an ecient operation. In accordance with the vpresent invention, a residual oil is air blown under controlled critical conditions. Asphalt-,ic constituents are then removed from the air blown residuum and the resulting high yield deasphalted product utilized as a high quality lube oil, as a high quality fuel, or utilized in a catalytic cracking operation.

It is well known in the art to treat mineral oils by various processes in order to remove undesirable high boiling and asphaltic constituents from these oils. For example, it is known to employ light hydrocarbon solvents, as for example, hydrocarbons such as propane and butane, in order to remove undesirable constituents, such as, asphaltic constituents therefrom. In these operations various temperatures and pressures are employed, as well as `various solvent to oil ratios. It is also known in the art to. use various other processes for the removal of carbon, and ash-forming constituents therefrom in order to prepare high quality lube and fuel oils. Other processes have also generally been directed toward the preparation of satisfactory high boiling feed stocks for a fluid catalytic cracking operation.

It has now been discovered that undesirable high boiling constituents may be efficiently removed from feed stocks boiling in the reduced crude boiling range, providing the reduced crude or residual oil is air blown under controlled conditions prior to deasphalting with a deasphalting solvent, as for example, propane. The process of the present invention, producing increased yields of deasphalted oil, may be readily understood by reference to the drawing illustrating one embodiment of the same.

Referring specifically to the drawing, a feed oil, as for example, a West Texas crude, is introduced into distillation rzone I by means of feed line 2. Temperature and pressure conditions in zone l are adjusted to secure the desired fractionation of the crude oil. Low boiling hydrocarbon gases are removed overhead from zone I by means of line 3; a hydrocarbon fraction boiling in the light naphtha range is removed by means of line 4, a hydrocarbon fraction boiling in the heavy naphtha range is removed by means of line 5, while a gas oil fraction is removed by means of line 6. A fraction boiling in the reduced crude boiling range, as for example, in the range above about 600 to '700 F., preferably boiling in the range above 750 F., is segregated as a bottoms fraction by means of line l, It is to be understood that zone I may comprise any suitable number and arrangement of distillation zones or stages.

In accordance with the present invention,l the high boiling reduced crude is air blown in zone I0 under controlled conditions as hereinafter described. The air blown residuum is introduced into a deasphalting zone 8 wherein it is preferably countercurrently contacted with a deasphalting solvent, as for example, propane which is introduced into deasphalting zone 8 by means of line 9. Temperature and pressure conditions in zone 8 are adjusted to secure the desired removal of asphaltic constituents from the residual oil. A, residual oil-propane mixture is removed overhead from zone 8 by means of line I3 and introduced into va distillation zone I5. Temperature and pressure conditions in Zone I5 are adjusted to remove overhead by means of line 50 propane which is preferably recycled to Zone 8. A residual fraction is removed from the bottom of distillation zone I5 by means of line 5| and preferably combined with a portion of the gas oil stream withdrawn from zone I which is introduced into line 5| by means of line 52. This gas oil may be removed from the system by means of line 60. Deasphalted oil may be removed by means of line 6I and utilized as a high quality fuel or lubricating oil.

The asphaltic constituents are removed from zone 8 by means of'line 53 and passed to a distillation zone 54, wherein a separation is made between the propane and the asphaltic constituents. 'Ihe propane is removed overhead by means of line 55 and preferably recycled to zone 8 while the asphaltic constituents are removed as a bottoms by means of line 56 and further rened or handled as desired. It is to be understood that zones, l5 and 54 may comprise any suitable number and arrangement of stages.

The present invention is broadly concerned with an improved process for the removal of undesirable high boiling constituents and asphaltic constituents from residual oils. The invention comprises utilizing in conjunction with conventionalv solvents, an air blowing operation. The resultant deasphalted product, as pointed out heretofore, is suitable for the production of high quality lube oils, high quality fuel oils, and

is particularly adapted as a feed stock to a fluid catalytic cracking operation.

The Ideasphalting v solvent may 'comp-rise low boiling hydrocarbons, as for example those containing from 2 to 5 carbon atoms in the molecule, or mixtures thereof. Particularly desirable solvents comprise propane and butan-e. The amount of solvent used per volume of oil may vary from 4 to 10, preferably in the range from 6 to 3 volurnes of solventper volume of oil. The mixture is generally heated to a temperature in `the range from about F. to 160 F., preferably to a temperature inthe range from 110 to 140 F. The deasphalting operation may comprise a batch operation or a countercurrent treating operation wherein the oil is introduced into the top of the tower, the propane is introduced into the bottom of the tower, and wherein deasphalted oil is removed from the top of the tower and asphaltic constituents from the bottom of the tower. In conducting an operation of this character, a temperature gradient is preferably maintained throughout the tower.

As heretofore disclosed, the ydeasphalted residual fraction withdrawn from zone l5, in accordance with a specific adaptation of the present invention, may be combined with a portion of the gas oil fraction segregated in zone I and introduced into a fluid catalytic cracking operation.

The uid catalytic cracking operation coniprises three sections: cracking, regeneration, and fractionation. The cracking reaction takes place continuously in one reactor, the spent catalyst being removed continuously for regeneration in a separate vessel, from which it is returned to the cracking vessel. Continuity of ow of catalyst as well as of oil is thus accomplished, and the characteristic features of fixed-bed designs involving the intermittent shifting of reactors through cracking, purging, and regeneration cycles are eliminated.

Regenerated catalyst is withdrawn from the regenerator and fiows by gravity down a standpipe, wherein a sufciently high pressure head is built up on the catalyst to allow its injection into the fresh liquid oil stream. The resulting mixture of oil and catalyst ows into the reaction vessel, in which gas velocity is intentionally low, so that a high concentration of catalyst will result. The cracking that takes place results in carbon deposition on the catalyst, requiring regeneration of the catalyst. The crackedproduct oil vapors are withdrawn from the top of the reactor after passing through cyclone separators to free them of any entrained catalyst particles, while the spent catalyst is withdrawn from the bottom of the reactor and is injected into a stream of undiluted air which carries the catalyst into the regeneration vessel. The products of combustion resulting from the regeneration of the catalyst leave the top of this vessely and pass through a series of cyclones where the bulk of the entrained catalyst is recovered. The regenerated catalyst is withdrawn from the .bottom of the vessel to complete its cycle.

Again referring specifically to the drawing, in accordance with a specific preferred adaptation of the present invention, the treated oil removed by means of line 5l is introduced into a catalytic cracking zone 22.

Temperature and pressure conditions in cracking zone 22 are adjusted to secure the desired conversion of the fee-d oil. Cracked products are removed overhead from zone 22 by means of line 23 and passed into a fractionation zone 24. Temperature and pressure conditions in fractionation zone 24 are adjusted to remove overhead by means of line 25y hydrocarbon constituents boiling in the gasoline and lower boiling ranges. This stream is `passed to a stabilizing unit where a gasoline fraction of the desired volatility is segregated. A heating `oil fraction is removed by means of line 2B. while a fraction boiling in the light cycle oil boiling range is. removed by means of line 2l. A bottoms fraction or heavy cycle oil is removed by means of line 28 and handled as desired. Spent catalyst is removed from the bottom of zone 22 by means of line 29 and passed into a regeneration zone 20 by means of line 2|. Suiiicient air is introduced. into the system by means of line 32. Regenerated catalyst is removed from the bottom of zone 30 by means of line 33 and passed to the reactor along with the feed by means of line I'I.

The invention is Ibroadly concerned with the removal of undesirable materials from petroleum oils, particularly from petroleum oils boiling in the reduced crude boiling range. Petroleum oils treated in accordancewith the present invention are particularly adapted as feed stocks for a catalytic cracking reaction. Although the invention may be adapted for the treatment of mineral oils boiling overl wide ranges as pointed out above, it is particularly adapted for the treatment of oils boiling above about 750J F., preferably boiling above about 860 F.

As discussed above, the invention is particularly concerned with an improved operation which comprises the air blo-wing or a reduced crude prior to deasphalting the same. It is well known in the art to 4produce cracked naphthas by a fluidized solids catalytic operation wherein the cracked product comprises constituents boiling in the motor fuel boiling range, as for example, below about 430 F. The crack-ed product also comprises normally gaseous constituents, as for example, those containing three carbon atoms and less in the molecule. The uidized solids technique for processing feed fractions, as for example, gas oils, heavy residuums and other feed stocks for the production of hydrocarbon fractions boiling in the motor fuel boiling range is a conventional one. As pointed out heretofore, the system of a fluidized solids technique comprises a reaction Zone and a regeneration zone, employed in conjunction with a fractionation zone. The reactor and the catalyst regenerator are arranged at approximately an even level. The operation of the reaction zone and the regeneration zone is conventional, which preferably is as follows:

An overiiow pan is provided in the regeneration zone at the desired catalyst level. The catalyst overflows into a withdrawal line which preferably has the form of a U-shaped seal leg connecting the regeneration zone with the reaction zone. The feed stream introduced is usually preheated to a temperature in the range from about 500 to 650 F. in exchangers in heat exchange with regenerator iiue gases which are removed overhead from the regeneration zone, or with cracked products. The heated feed stream is withdrawn from the exchangers and introduced into the reactor. IThe seal leg is usually suiciently below the point of feed oil injection to prevent oil vapors from backing into the regenerator in case of normal surges. Since there is no restriction in the overnow line from the regenerator, satisfactory catalyst flow will occur as long as the catalyst level in the reactor is slightly below the catalyst level in the regenerator when Vessels are carried at about the same pressure. Spent catalyst from the reactor fiows through a second U-shaped seal leg from the bottom of the reactor into the bottom of the regenerator. The rate of catalyst flow is controlled by injecting some of the air into catalyst transfer line to the regenerator.

The pressure in the regenerator may be controlled at the desired level by a throttle valve in the overhead line from the regenerator. Thus, the pressure in the regenerator may be controlled at any desired level by a throttle valve which may be operated, if desired, by a differential pressure controller. If the pressure differential between the two vessels is maintained at a minimum, the seal legs will prevent gases from passing from one vessel into the other in the event that the catalyst iiow in the legs should cease.

The reactor and the regenerator may be designed for high velocity operation involving linear superficial gas velocities of from about 2.5 to 4 feet per second. However, the supercial velocity of the upiiowing gases may vary from about 1-5 and higher. Catalyst losses are minimized and substantially prevented in the reactor by the use of multiple stages of cylone separators. The regeneration zone is provided with cyclone separators. These cyclone separators are usually from 2 to 3 and more stages.

Distributing grids may be employed in the reaction and regeneration zones. Operating temperatures and pressures may vary appreciably depending upon the feed stocks being processed and upon the products desired. Operating ternperatures are, for example, in the range from y the range from about 5 to 20%.

wherein the weight per cent of the alumina is in Another preferred catalyst comprises silica-magnesium where the weight per cent of the magnesia is about 5% to 20%. These catalysts may also contain a third constituent, as for example, T1102, W03, M00,`

BeO, BzOa, CdO', U03, B203, S1102, F8203, V205, MnO, CrzOa, CaO, T1203, Mg@l and Ce2O3 present in the concentration from 0.05% to 0.5%. The size of the catalyst particles is usually below about 200 microns. Usually at least of the catalyst has a micron size in the range from about 20-80. Under these conditions with the supercial velocities as given, a fluidized bed is maintained wherein the lower section of the reactor, a dense catalyst phase exists while in the upper area of the reactor a dispersed phase exists.

The above described operation, as pointed out, has not been entirely satisfactory for cracking heavy oils such as a reduced crude due to excessive formation of carbon and ash on the catalyst. However, by air blowing the reduced crude and deasphalting the same, unexpected desirable results are secured.

The present invention may be more fully understood by the lfollowing example illustrating the same:

for various time periods. operations are as follows:

Oxidation Period, Hours 0 0.5 l 2 3 5 8 Inspections of Pitch:

N aph. Insol.,1 Wt. Percent 15 18 22 25 30 36 38 Specic Gravity 1.003 1.013 1.018 1.023 1. 031 Conradson Carbon, Wt. Percent 21 22 (2) (2) (2) (2) 1 1 gram of sample is mixed with 5 cc. of carbon bisulde and 100 cc. of 86 API naphtha. The mixture is held at F. for content determined. 2 Could not be run.

catalysts. These catalysts are oxides of metals A preferred catalyst comprises silica-alumina 16 hrs. The mixture is then filtered, washed and weighed and insoluble 'I'he residuums which were air blown for one and ve hours were deasphalted with the results shown on the following table:

Eect of oidatz'on pretreatment on deasphaltzng of residuum Residuum Air Blown One Residuum Air Blown Five Materlal Deasphalted Vlrgln Res1duum As Is Hour at 550 F' Hours at 550 F.

Deasphalting Conditions:

Temperatura... 200 F 200 F 200 F. Solvent Treat. 600 Vol. percent.. 600 Vol. percent. Mixing Time 80 Minutes... M 30 Minutes. Settling Time d Do. Yields, Wt. percent:

Oil 36 (39 Vol. percent). Asphalt 64.

Feed Oil Asphalt Feed Oil Asphalt Inspections:

Specific Gravity API Gravity.

Viscosity- SSF/210 F SEF/ F..

Conradson Carbon, Wt. Percent Insol. 86 Naph. (Mod), Wt.

percent Insol. Benzene, Wt. percent Insol. Carbon Disulde, Wt.

percent Ash, Wt. percent Carbon, Wt. percent..- Hydrogen, Wt. percent. Sulfur, Wt. percent H/C Ratio, Atomic The results of thesel` It is` to benotedI that ir, blowing of thei i?esjil; forv one hour, gane excellent esults in'tllat the yield was inreelsed from), 551 vol.' peij ent to (55l vol. per cent. On: the 'other bend, air, blowing for ive'loouisl gave adverse results.l It is to be' noted that air blowing the residuum for one hout resulted in increasing the naphthai insoluble oontent to the level of the Coniadsn crbon on` the original pitch. Thus, they extent of the oir blowing may be somewhat determined bytliis criteijigi,

The present invention isl b roefdly conerned with an improved vd@asphalting operation of liea'vy residuunis whereby the yields are materially increased. The temperatures employed in the air blowing process are in the range from about 450 to 700rJ preferably in the range from 500 F. to 600 F, The time of iiblOWing Willysomewhat depend upon the temperatuije utilined, but in generalV shsouldfnot exceed about 3 hours and preferablyshouldfbe in the range from 1/2 to 2 hours. i

what is claimed is:

l. Process for the, production of hydrocaibon constituents boiling in the motor fuel boiling 11a/inge from a feedoll boiling above 4@bout 7505?.; comprising. air blowing saidfeed oil for a tim`e period of from about 1A to 2` hours atanL texrilzieal-v wemmerangefw inwiowwhereafie 1f'elrgfwviris'y esnhltib `on. stituerlts from thev @ir blown oil, then contglting s'afid oil with a suit#` sible iluidized 'eigoking oatvglyst, at elevated temperatures and pressures adapted to crack the oil and produ hydrocarbons. boiling in the mgtor fuel boiling range, passing said cracked proclut to ai distillationzone and segregating hydrocarbon constituents boiling in the motorv fuel boiling range.

2. Prooess as defined by claim l wherein the feed oil is 'an Oil Whzh boils above about 860 F.

References Cited inA tbe iile of this patent UNITED S'FIA'IIES PATENTS Number. Name Date 2,029,290 Bray et al. Feb. 4, 1936 2,070,567 Adams Feb. 16, 1937v 2,528,586 Ford Nov. '7, 1950 2,559,285 Douce July 3, 1951 REFERENCES Industriel and Engineering Chemistry, vol. 424, No. 10, October 1950, pages 2083-2095 incl. Aijticle by @dell et el.

Claims

1. PROCESS FOR THE PRODUCTION OF HYDROCARBON CONSTITUENTS BOILING IN THE MOTOR FUEL BOILING RANGE FROM A FEED OIL BOILING ABOVE ABOUT 750* F., COMPRISING AIR BLOWING SAID FEED OIL FOR A TIME PERIOD OF FROM ABOUT 1/2 TO 2 HOURS AT A TEMPERATURE IN THE RANGE FROM 450 TO 700* F., THEREAFTER REMOVING ASPHALTIC CONSTITUENTS FROM THE AIR BLOWN OIL, THEN CONTACTING SAID OIL WITH A SUITABLE FLUIDIZED CRACKING CATALYST AT ELEVATED TEMPERATURES AND PRESSURES ADAPTED TO CRACK THE OIL AND PRODUCE HYDROCARBONS BOILING IN THE MOTOR FUEL BOILING RANGE, PASSING SAID CRACKED PRODUCT TO A DISTILLATION ZONE AND SEGREGATING HYDROCARBON CONSTITUENTS BOILING IN THE MOTOR FUEL BOILING RANGE.