US2891004A - Process for removal of metal contaminants from high boiling oils by use of boron compounds - Google Patents

Description

`June 16, 1959 w, J, MATTOX 2,891,004

PROCESS F OR REMOVAL. F' METAL CONTAMINANTS FROM v HIGHBOILING OILS BY USE 0F BORON COMPOUNDS Filed Oct. 19, 1955 Igil5..

DECONTAMINATE'D OIIL HEAT/NG n .134

SEPARATOR J 35` @SWEEX GAsoL/NE 23 l M AND GAS l5 377 k P f f 36 v' 25 STEAM pl "LL vL| -I coNAMlNANT |15 ,Hlm

24\ u CYCLONES l, :l I; n :i l' :z: u il REAcToR l 1U 26 GQID M *1I-'f HEATING ou. l' ,I REGENERATOR smv *f 27 h 31 L ou. 2 5 CYC E 5^? 29 35 AIR sPENT BOTTOMS y cATALYsT William J. Maffox Inventor By Z716 AfOrney United States Patent BORON COB/IPOUNDS Judson, Mattox, Baton Rouge, La., assignor rto Esso Research and Engineering Company, a corporation of Delaware Application October 19', 1955, Serial No. 541,391 s claims. (c1. 20s-251) The present invention is concerned' with an improved process for the removal` of undesirable constituents from petroleum oils, particularly from petroleumv oils remainingafter` distillation of volatile components. The inventionl is more particularly concerned with an improved process for the preparation of satisfactory feed stocks for. a fluid catalytic cracking operation. In accordance with the present' invention, undesirable iron,` vanadium `and nickel constituents are removed from petroleum oils, particularly fromhigh boiling petroleum oils by an operation which comprises treating these oils with a compound of boron such as boron oxide and boric acid followed by the removal of these constituents.

The present invention is a continuation-impart of U.S'. Serial No. 258,624, tiled November 28, 1951;. now abandoned.

It is well" known in the art to treat mineral oils by various processes in order to remove undesirable constituents `from these oils. For example, it is known to employlighthydrocarbon solvents, as for example, hyf drocarbons such as propane and lontane 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 variousother processes for `the preparation of high quality oil's such as those for the removal of gum and ash-forming constituents therefrom. Theseprocesses have generally` been directed toward the preparation of satisfactory high boiling `feed stocks `for a fluid catalytic cracking operation. Ina catalytic cracking operation, the removal of iron, nickel and vanadium compounds from feed stocks isd`esirable since the use of feed stocks, as for example reduced crudes, containing these undesirable constituents isprohibitive due to the excessive formation of dry gas, carbon andash.

It has'now been discovered that undesirable metals or metalcompounds such as various oxides or salts of iron,

vanadium, nickel, sodium, and calcium may be eflciently removed from feed-stocks of the reduced crude type, pro.- vidingi the crude is treated with a boroncompound, preferably` atl elevatedtemperatures. The process of the presentiinvention may be readily understood by reference to the drawing illustrating one embodiment ofthe same.

Referring specifically tothe drawing, a feed oil, as for example, a West Texas crude, is introduced into distillation zone 1 by means of feedline 2. Temperature and pressure conditions areiadjusted in zone 1 to secure the desired fractionation of the crude oil. Light hydrocarbon gases'are removed overhead by means of line3; a lower boiling hydrocarbon fractionis removed by means of line l4",1a`l1igher boiling hydrocarbon fraction is removed by means of line 5, and a somewhat higher boiling fraction is removed by means of line 6. A fraction boiling-in the reduced` crudeboilng range, as for example, in the range above about 600 to 700 F., preferably boiling inthe rangeabove 750 F., is segregatedas a bottoms fraction bysmeansof line 7; It isto be understood that zone 1 2t may` comprise any suitable number and arrangement of distillation` zones or stages.

In accordance with the present invention, the'high boil:- ingoil is raised to an elevated temperature in heating zones and passed toV treating and mixing zone 9by means of line l10` wherein it is contacted witha borony compound introduced into zone 9 `by means of line 11., It is to vbe understood that treating andmixing zone` 9 likewise may comprise any suitable number and arrangement of stages.

The boron compound may be introduced, through lines 11 and 10, to a mixer 9 asa sluiry in a portion of the reduced crude or other suitable oil o1' as an Oil-insoluble molten phase. Mixer 9 is of such design as to provide intimate contact of the oil andv molten boron-containing compound and of such capacityv as to permit adequate reaction time between metal-containing hydrocarbons and the boron additive.` The effluent from mixer 9A is passed through line 13 to separator 3.4 held at an elevated .temL pferature of about 300 to 500 F.. or sufficient to maintain the components in a uid conditionand thereby facilitate separation and settling of the boron complex.r The boron complex, which now contains metal contaminants, is withdrawn throughline" 35' and either. Idischarged through line 36lor passed through line 37 to steam stripping zone 1'4 for boron recovery. Decompositionof` the boroncomplex in zone 14` and'volatilization. of the boron oxide by means of steam introduced ythrough line` 15 permits re'- turn of a major portion ofthe boron to the system through line'16.

The treated oil free of'undesirable iron, vanadium and nickel compounds is removed from zone 14 by means `of line 17 and introduced into a fluid catalytic cracking operation. The liuid catalytic cracking plant is composed of three sections: cracking, regeneration,` and fraction-V ation'. The cracking reaction takes place continuously in one reactor, `the spent catalyst being removedr continu ously for regenerationv in a separate vessel, from -Which it is returned to the cracking. vessel. Continuity of flow of catalyst aswell as of'oil is thus accomplished, and the` characteristic features of lixedbed designs .involving the intermittent shiftingy of reactors through .cracking,.purg; ing, andl regeneration cycles are eliminated. i

Regenerated catalyst is withdrawn from the regenerator and flows by gravity down a standpi'ne,4 wherein. a sufiicientl'y high pressurehead is built up on the catalyst to allow its injection into'the fresh liquid oil stream. TheA resulting mixture of oil and catalyst flows into thereaction vessel, in which `gas velocity s `intentionally low, `so thatfa highL concentration of' catalyst will result.. The cracking thatA takes place results in carbon deposition on the. catalyst, requiring regeneration of the catalyst. The4 through. a series of cyclones where thebulk of `the entrained catalyst is recovered. The regenerated catalyst is..withdrawnV from the bottom of the vessel to complete its cycle.

ance witha preferred adaptation of the presentinvention,

the treated oil removed by meansof line 17 is introduced, mtoacatalytic cracking zone 22.

Temperature and pressure conditions in cracking zone 22` are adjusted to secure the desired conversion ofthe` feed oil. Cracked products are removedoverhea'difrom.l zone 22 by means of line 23 andpassedinto a fractionaw tion zone. 24': Temperature andpressureconditionswm fractionation zone 24 are adjusted to remove overhead by means of line 25 hydrocarbon constitutents boiling in lthe 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 26 while a fraction boiling in the cycle oil boiling range is removed by means of line 27. A bottoms fraction 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 30 by means of line 31. Sufficient 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 yline 17.

The invention is broadly 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 accordance with the present invention are particularly adapted as feed stocks for a catalytic cracking reaction. Although the invenfrom backing into the regenerator in case of normal surges. Since there is no restriction in the overow 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 flows 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 linetoY the regenerator.

The pressure in the regenerator may be controlled at i the desired level by a throttle valve in the overhead line pressure controller.

tion may be adapted for the treatment of mineral oils r boiling over wide ranges as pointed out above, it is particulanly adapted for the treatment of oils boiling above about 750 F., preferably boiling above about 860 F.

Various compounds of boron as well as boron may be employed, as for example boron oxide and boric acid. The boron compounds may be added in solid or in liquid form and the thermal treatment carried out in coils, fractionating columns or in uid beds. The boron compound may be supported on Various porous materials by impregnation or ysteam volatilization. Molten boric acid may also be utilized. The amount of boron compound added is preferably in the range from about .5 to 3% by weight of the feed oil. It is preferred to employ from about 1% 4to l1/2% of the boron compound by weight. The temperature of contact should be in the range from about 250 to 850 F. A preferred range for contacting the boron compound with the feed oil is in the range from about 600 to 700 F.

As discussed above, the invention is particularly concerned with an improved operation which comprises the treatment of a reduced crude by contacting it with boron or with a boron compound and then to use the trea-ted stock to secure an improved fluid catalytic cracking operation. It is well known in the art to produce 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 cracked product also comprises normally gaseous constituents, as for example, those containing three carbon atoms and less in the molecule. The luidized 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 uidized 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 overow pan is provided in the regeneration zoneA 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 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 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 lthe other in the event that the catalyst flow in the legs should cease. u

The reactor and the regenerator may be designed `for high velocity operation involving linear supercial gas velocities of from about 2.5 to 4 feet per second. l However, the superficial velocity of the upowing gasesmay vary from about 1-5 and higher. Catalyst lossesr are f minimized and substantially prevented in the reactor by and regeneration zones.

the use of multiple stages of cyclone separators.l The regeneration zone is provided with cyclone separators, These cyclone separators are usually from 2 to 3 and more stages. l

Distributing grids may be employed in the reaction Operating temperatures and pressures may vary appreciably depending upon the feed stocks being processed and upon the products desired. Operating temperatures are, for example, in the range 1 from about 800 to 1000 F., preferably about 85.0-

950 F., in the `reaction zone. Elevated pressures may be employed, but in general pressures below 100 lbs. per sq. in. gauge are utilized. Pressures generallyV inthe range from 1 to 30 lbs. per sq. in. gauge are preferred. A catalyst holdup corresponding to a space velocity of l to 20 weights per hour of feed per weight of catalyst is utilized. A preferred ratio is 2 to 4. Catalyst to oilV ratios of about 3 to 10, preferably about 6 to 8 by weightare used.

The catalytic materials used in the fluidized catalyst cracking operation, in accordance with the present invention, are conventional cracking catalysts. These catalysts are oxides of metals of groups II, III, IV and V of the periodic table. A preferred catalyst comprises silicaalumina wherein the weight percent of the alumina is ,in Another preferred catalyst comprises silica-magnesia where the weight percent of the magnesia is about 5% to 20%. The size ofV the catalyst particles is usually below about 200 microns.l Usually at least 50% of the catalyst has a micron size .in the range from about 20-80. Underthese conditions The seal leg is usually sufficiently" with the superficial velocities as given, a fluidized bedis maintained where in the lower section ofthe r'eactor,'al dense catalyst phase exists while in the upper area of the reactor a dispersed phase exists.

Y 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 ldry gas, carbon, and ash on the catalyst. However, by combining the boron treating stage with the catalytic crack` ing stage, an improved operation results when using feedstocks of this character.

What is claimed is: 1 l. An improved process for the removal of lron, nickel and vanadium contaminants from a hydrocarbon oil boil` ing above about 750 F. which comprises contacting said oil with from about 0.5 to about 3% by weight, based upon the oil, of a boron compound selected from the group consisting of boron oxide and boric acid at a temperature above about 250 F.; separately recovering a `boron complex and decontaminated oil; decomposing said boron complex with steam; and recovering at least a portion of said lboron compound.

2. A process as defined by claim l wherein said oil is contacted with said boron compound at a temperature in the range of from about 600 F. to about 800 F.

3. A process as defined by claim 1 wherein said oil is contacted with from about 1% to about 1.5% of said boron compound.

4. A process as defined by claim 1 wherein said boron compound is boron oxide.

5. A process as defined by claim 1 wherein said boron compound is boric acid.

References Cited in the le of this patent UNITED STATES PATENTS 2,222,596 Scafe Nov. 26, 1940 2,611,735 Coons Sept. 23, 1952 2,685,561 Whiteley et al. Aug. 3, 1954 OTHER REFERENCES Mellor: Modern Inorganic Chemistry, Longmans, Green and Co., New York, publishers (1925), p. 767.

Wrightson: Analytical Chemistry, vol. 21, No. 12, December 1949, p. 1543.

Proving Ground, published by Esso Oilways; copyright 1955 by Esso Standard Oil Company, p. 20.

Claims (1)

1. AN IMPROVED PROCESS FOR THE REMOVAL OF IRON, NICKEL AND VANADIUM CONTAMINANTS FROM A HYDROCARBON OIL BOILING ABOVE ABOUT 750* F. WHICH COMPRISES CONTACTING SAID OIL WITH FROM ABOUT 0.5 TO ABOUT 3% BY WEIGHT, BASED UPON THE OIL, OF A BORON COMPOUND SELECTED FROM THE GROUP CONSISTING OF BORON OXIDE AN D BORIC ACID AT A TEMPERATURE ABOVE ABOUT 250* F.; SEPARATELY RECOVERING A BORON COMPLEX AND DECONTAMINATED OIL; DECOMPOSING SAID BORON COMPLEX WITH STEAM; AND RECOVERING AT LEAST A PORTION OF SAID BORON COMPOUND.

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