US2853426A - Solvent deasphalting of residual oils with wash oil to remove metal contaminants - Google Patents

Description

Sept- 23, 1958 N. P. PEET 2,853,426

SOLVENT DEASPHALTING oF RESIDUAL. OILS WITH,

WASH OIL. T0 REMOVE METAL CONTAMINANTS Filed March 10, 1955 5 Sheets-Shea?I 1 /7 DEASPHAUED 0/1. /N PmPA//E' saLur/af/ Sept. 23, 1958 N. P. FEET 2,853,426'

SOLVENT DEASPHALTING OF RESIDUAL OILS WITH WASH OIL TO REMOVE METAL CONTAMINANTS Filed Ilarch 10, 1955 3 Sheets-Sheet 2 ArroR fr.

SOLVENT DEASPHALTING OF RESIDUAL OILS WITH WASH OIL T REMOVE METAL CON- TAMINANTS Nick P. Peet, Baytown, Tex., assigner, by mesne assignvments, to Esso Research and Engineering Company,

Elizabeth, N. J., a corporation of Delaware Application March 10, 1955, Serial No. 493,371

22 Claims. (Cl. 196-14.46)

y The present -invention is directed to a method of removing metal contaminants from petroleum fractions. More particularly, the present invention is concerned with the deasphalting of residualv petroleum fractions and the removal of metals during said deasphalting operation. In its more specific aspects, the invention is concerned with the removal of metal contaminants from residual fractions charged to a catalytic cracking operation.

The present invention may be briefly described ,as a method for treating a petroleum fraction containing a major portion of components boiling abo-ve about 900 F. and which is contaminated by substantial amounts of metal contaminants in which the feed stock is introduced into a deasphalting zone and there contacted with liqueiied, normally gaseous hydrocarbon and a fraction, of

catalytic cycle stock as hereinafter defined under condi-- carbons which may be used may be mentioned ethane, propane, propylene, butylene, butane, includingV iso and f normal butane and mixtures thereof. The ethanev under some conditions may contain ethylene and be used suit-l ably in the present invention. itations inoperating equipment, it is preferred to Vuse butane, propane, propylene, butylenes or mixtures thereof Because of pressure lim- 1 isy maintained with the catalyst being.- removed4 from the with a desirable commercial mixture consisting of about 30% butanes and about 70% propane.

The amount of liquefied, normally gaseous hydrocarbon employed as a solvent in the deasphalting operation ofthe present invention is Within the range of about 2 to aboutl0 Volumes o-f thesolvent per volume ofA residual petroleum fraction employed as afeed stock to the deasphaltingl zone. As a specific example, it has been foundthatabout 3.2 volumes of liquefied, normally gaseous hydrocarbon solvent by volume of residual oil charged .is a desirableV asphalted oil is withdrawn being maintained at 180 F.

and the bottom of the tower Where the asphalt is introduced with the residual oil being 160 F. Y

The invention may also be carried out in a plurality of stages in one vesselor in a plurality ofvessels compris.-

ice

Z Y ing a plurality of stages. The separate stages may be conducted with a temperature gradient and pressure gra-l dient between the stages. For example, a temperature and pressureof F. and 550 pounds per square inch gauge may be maintained in the top of one vessel where as the temperature and pressure in a second vessel may b e from about to 180 FQ and from about 400 to 500l pounds per square inch gauge. Y.

The vessels comprising the several stages, as desired, may be arranged either in the vertical or horizontaljposition or intermediate thereof. For example, one or more vessels may be vertically arranged and one or more vessels may be horizontally' arranged or arranged at an angle with the horizontal to allow thel vesselV also to be used as a,

settling zone for separation of asphalt'i'c material.

The present invention is particularly useful in preparing a feed stock for catalytic crackingv operations and particularly catalytic cracking operations of. the fluidized solids.,

or powder type. The catalytic cracking operation may be either of the upflow or downfiow type.. yIn, the uptlow loperation the` vaporized. hydrocarbon is contacted with the;

uidized solids in a 4suspension'and the suspension flowed.y

upwardlyk through a reaction zone.` Likewise, inl thesof called upiiow operation. the catalyst is regenerated by susdisperse phase andreturned to the dense' phase withthey reaction products liowing outy of the reactor and the cat-y alyst. liowing downwardly therefrom. In` the so-calledl downtiow cracking operation, the catalystl fouled with car'- bonaceous. material and/ or coke is regenerated by suspending it in a combustion supporting gas, such as air, and

owing same into a regeneration zone wherein a'disperse phase and a dense phase are maintained, they combustion,`

products being1 led off from thefdisperse phase after' separation of `a major amount of catalyst therefrom and' the 2,587,554, issued February 26, 1954, in the nameof lohn Weikart.

In such' catalytic cracking'op'era'tion's' it has been found` that if the charging stock contains' any metal contaminants insignificant amounts, for example,'as little as. l poundof nickel or yless per thousand' barrels of c'harge stock, ther catalytic cracking process' is"advers`ely'affected. In general, other metal components such as vanadium aiidl iron are'undesirableinthesamema'n'ner as is nickel but are less troublesome; 'on a weight basis it may be considered that vanadium is perhaps 1/stli as troublesome asnickel` and iron is perhaps 1/2 as troublesome as nickel. Here-V after `in the specification and claims where the expression equivalent to" 1l0` 'pound of nickelA per thousand' ba'rrels of oil appears, it is to be understood that' this is intended toenc'ompass'the'metal components' nickel, vanadiumand iron with' nickel use'd at its' full value, vanadium considered atv 1/sth its actual Weight value and iron considered at l if's actual weight value. f

In the practice of the present invention wherein. residual Patented Sept. 23, 1958 A description of. such a catalytic cracking operation may be" found in U. S. 'Patent ing operation such as oneof the fluidized solids type as mentioned supra.

This wash oil, as mentioned, is a fraction of a catalytic cycle stock which is cut from the cycle stock at a tempera ture above about 900 F. and preferably at a temperature in the range from about 900 F. to about 1050 F. This wash oil may have a softening point in the range from about 100 to 125 F., a specific gravity inthe range from about 1 to about 1.2 with the preferred range from 1.05 to about 1.08, a flash point in the range from about 550 to 650 F. and should remove about 85% of the nickel contaminants from the residual oil which is contaminated with the metals down to about 0.5 part per million of metallic contaminants. y

The wash oil may be secured by fractionally distilling the products from a catalytic cracking operation of the typementioned supra at a cut point of about 900*to about 1050 F. The wash oil may suitably be obtained also by precipitating a portion of the cycle stock'from a catalytic cracking operation and employing the same either with or without the removal of the precipitating agent which may be a liquefied, normally gaseous hydrocarbon.

The wash oil may also be obtained from `the distilled products from a catalytic cracking operation by taking a broad residual fraction from the distillation of thecracked products and subjecting it to a clarification operation to remove heavier fractions and residual-catalyst contained in the products from a catalytic cracking operation of the fluidized powder type. The clarified 'oil may be employed as a wash oil after suitable treatment such as by solvent precipitation and/ or distillation. Preferably the wash oil is a fraction of catalytic cycle stock which is recovered by distillation. l

The term cycle stock as employed in the present invention and in the sense used here refers to a fraction recovered as a distillate intermediate the heating oil fraction and the residual fraction resulting from distillation of the catalytically cracked products. The term fraction of catalytic cycle stock means a fraction which is intermediate the heating oil fraction and he heavier residues remaining after the distillation of the lighter material from the cracked product from the catalytic cracking of hydrocarbons.

A desirable wash oil for use in the present invention V- by wet ash, p. p. m Fe by wet ash, p. p. m

The present invention will be further illustrated ,by reference to the drawing in which:

Fig. 1 is in the form of a diagrammatic ow sheet illustrating a simplified preferred procedure for carrying out the deasphalting step of the present invention;

Fig. 2 illustrates the employment of the present 'inven- Y tion in a catalytic cracking operation and the of the fraction of the catalytic cycle stock; A

Fig. 3 is a diagrammatic ow sheet of a modificationl of Fig. 2;

Fig. 4 is a still further diagrammatic lloW sheet oifan-V other mode of practicing the present invention;v

preparation Fig. 5 is a diagrammatic flow sheet of a modified procedure for carrying out the deasphalting step of the present invention; and

Fig. 6 is a diagrammatic flow sheet of another modified procedure for carrying out the process of the present invention.

Referring now to the drawing in which identical numerals will be employed to designate identical parts, in Fig. 1 a deasphalting tower, such as 11, is provided into which a crude residue is introduced at approximately a central part thereof through line 12 and through a spider or distributing means 13. Propane or other liqueed, normally gaseous hydrocarbon is introduced into the tower'11 by way of line 14 to ow countercurrently to the residual fraction introduced by line 12. A wash oil which is a fraction of catalytic cycle stock is introduced into the upper portion of tower 11 through line 15 and ows downwardly therein after being distributed through a spider or distributing means 16.

Deasphalted oil in propane solution is removed from the upper portion of the tower 11 by way of line 17 and after stripping of dissolved propane may be introduced as a feed stock into a catalytic cracking operation. Asphalt is removed from the bottom of the tower by way of line 18 and this asphalt contains substantially all of the metal* contaminants present in the crude residue introduced by line 12. The conditions in deasphalting tower f 11 are those exemplified supra.

In Fig. 2 another mode of operation is performed in which crude oil which contains metal contaminants, such as nickel, vanadium, iron, 'and the like, is introduced into the system by way of line 20 and charged to a fractional distillation zone 21 which may be a plurality of fractional distillation towers, each equipped with internal vapor-liquid'contacting means, such as bell `cap trays. Zone or tower 21 is provided with a heating means as illustrated by a stream coil 22 for adjustment of temperaturesand pressures therein. In distillation zone 21 light fractions including gasoline may be removed by line 23, kerosene fractions by line 24, and heating fractions by line 25 and a gas oil fraction by line 26. Crude residue may be discharged from Zone 21 by line 27 for further processing as will be described.

The gas oil fraction is then charged by line 26 into a catalytic cracking zone 28 of the type illustrated supra wherein catalytic cracking takes place at temperatures, for example, from about 800 to about ll50 F. The cracked products issue from zone 28 which is shown as a block in the flow diagram by line 29 and introduced thereby into a distillation tower or zone 30 which, like zone Y21, is provided with internal vapor-liquid contacting means and with a heating means illustrated by steam coil 31.

In zone 30 conditions of temperature and pressure are adjusted to take overhead a light fraction through line 32, gasoline components through line 33 and heating oil through line 34. A residual fraction including finely divided catalyst which may have carried over from zone 28 by line 29 is discharged by line 32a. A fraction of catalytic cycle stock cut at a temperature of about 900 to l050 F. is withdrawn from zone 30 by line 33a and charged into zone 11 through spider or distributing means 16.

The crude residue withdrawn from zone 21 by line 27 controlled by valve 34a is introduced into line 12 deasphalted oil substantially free of liquefied, normallyv gaseous hydrocarbons is removed from stripper 35 by line 38 and introduced thereby into line 26 for charging in the catalytic cracking zone 28 in admixture with the hydrocarbons in line 26 or alone as may be desired.

It may be desirable not to charge the crude residue fromy zone 21 into zone 11 and under these circumstances the crude residue in line 27 rnay be withdrawn from the system through line 39 controlled by valve 40 or only part of the reisdue in line 27 may be charged to line 12. Likewise, other crude residue may be introduced into zone 11 by opening valve 41 in line 12 connecting to a source of other crude residue which Iare contaminated withmetals.

A still further mode of the present invention may be illustrated with respect to Fig. 3. In this particular mode, the feed stock to catalytic zone 28 is introduced by line 26 and submitted to cracking operations therein to form a product which is withdrawn by line 29 into distillation zone 30. In this particular instance, a broader fraction may be obtained through line 33a than with respect to Fig. 2 by omitting the side stream Withdrawn by line 34 by closing off line 34 by valve 34b. Under these conditions, the fraction rin line 33a may suitably be admixed with a liquefied, normally gaseous hydrocarbon, such as one of the type mentioned before, introduced by line 50 and the admixture iiowed into a precipitation zone 51 which may be operated similarly to deasphalting zone 11 to obtain a fraction of the catalytic cycle stock, the oil solution of liquefied, normally gaseous hydrocarbon removed from the catalytic cycle stock being discharged from zone 51 by line 52 while the precipitated material is discharged from zone 51 by line 53 into line 54 whichv is controlled by valves 55 and 56. By closing valve 55 the material from zone 51flows into a stripping zone 57 provided with a heating means 58 for removal of liquefied, normally gaseous hydrocarbon by line 50 for reintroduction into line 33a, the oily material free of normally gaseous hydrocarbon then being introduced by line 59 controlled by valve 60 into deasphalting tower-11 through spider 16.

In another mode of the present invention, thematerial from line 53 and line 54 without removal' of normally gaseous hydrocarbon would be flo-wed directly into line 59 by closing valve 56 and'opening valve 55, Under these circumstances, the material introduced into line 59 by way of line 54 will supply at least part of the liquefied, normally gaseous hydrocarbon which may be supplemented by liquefied, normally gaseous hydrocarbon introduced into tower 11 by line 14 for treatment of crude residue introduced yby line 12 through spider 13, the precipitated asphalt being withdrawn by line 18 and the deasphalted oil free of metallic contaminants then being also withdrawn by tower 11 by line 17 and introduced into stripper 35 for removal of liquefied, normally gaseous hydrocarbon by way of line 37 and to recover deasphalted oil by line 38 for introduction into line 26. It is to be noted that line 26 is provided with a valve 26a so as to regulate the amount of extraneous feed introduced by line 26.

A still further mode of the present invention is illustrated in Fig. 4 wherein two catalytic cracking zones are employed. In this mode, a catalytic cracking zone 70 -which may be of the upflow type and a catalytic cracking zone 71 which may be ofthe downow type are employed. Feed stock, such as gas oil, is introduced into zone 70 by way of line 72 and submitted to cracking in a fluidized powder operation to form a cracked product which is discharged from zone 70 by line 73 and introduced thereby into a distillation zone 74 which, like zones 30 and 21, is provided with suitable internal vapor-liquid contacting means to allow a sharp separation among the products. Heat is supplied for adjustment of temperature and pressure in zone 74 by a heating means, such as steam coil 75. Light fractions are removed from; zone 74 by line 76, intermediate boiling' fractions` by lines 77 and 78 and a rather broad cycle stock fractonwhich contains catalyst carried over to zone 74 byl line 73 is withdrawn by line 79 into a clarier, such as a Dorr thickener 80, wherein a separation is made between the catalyst and heavier fractions and the clarified oil, the heavier fractions being discharged from thickener '80y by line 81 while the clarified oil is' Withdrawn by line 82 controlled by valve 84 for further treatment as will be described.

A feed stock, such as a gas oil, isr introduced into catalytic cracking zone 71 by way of line '85' and` cracked as a suspension to form a product which is withdrawn from` zone 71 by line 86, the claricd oil in line 82 being, admixed with the cracked products either in line `86- or in distllation zone 87 into which the claried oi-l and the cracked products are introduced. Zone 87 is providedv with suitable internal vapor-liquid contacting means tok make a separation of the lighter products from the catalytic cycle stock and to recover the desirablefractionsY fied oil and cycle-stock from zones 70 and 71 is discharged from zone 87 by line 91 controlled by valve 92 and introduced through spider or distributing means 16 into deasphalting tower or zone 11 wherein iticontacts the contaminated crude residue introduced by line 12 andspider 13 and propane introduced by line 14 to precipitate as-` phalt containing the metal contaminants which is removed by line 1'8.

The deasphalted oil in propane solution is withdrawn' by line 17 into stripper 35 and the propane removed by-l line 37, the deasphalted oil free `of propane being withdrawn by line 38 and introduced into line '85 for cracking in zone 71.

It is to be understood that the deasphalted oilin line 38 may be charged to zone 70 or z-one 71 or to both of them as may be desired.

It is to be noted that the clarified oil in 1ine'82 may be routed at least in part as may ben desired into a precipitation zone such as 51 by opening valve 94 in branch line for recovery of wash oil by line 52 fo-r use in zone 11;

While the present invention has been described with respect to Fig. 4 with the clariiiedA oil from thickener 80 being directed into zone 87, it is understood'thatthe clarified oil from zone 80 and the cycle stock from either or both of zones 74 and 37 may be combined and distilled or subjected to treatment for recovery of a fraction of the cycle stock in a separate distillation zone; or, alternatively, the icycle stocks and claried oil in admixture may be subjected to a solvent precipitation treatment as desired either with. or withoutsubsequent distillation.

In Fig. 5, a modied procedure for the deasphalting operation is described. Specifically, Fig. 5` refers to the employment of a plurality of stages with a temperature and pressure gradient between the stages. In Fig. 5, the tower 11 may comprise a plurality of stages and the incorporator and settler 101 comprise an additional stage; Wash oil of the type described .supra and derived from catalytic cycle stock is introduced into the system by line 102 'which connects into line 103 by way of which the wash oil is introduced into the top of deasphalting tower or zone 11 by way of spider or distribution means 16. The deasphalted oil in propane-butano solution leaves the tower 11 by line 17 for. removal of propane-butane and for subsequent use as a catalytic cracking stock. Asdescribed previously, the crude residue is introduced into tower 11 by line 12 and through spider 13 while propane- -butane solvent is introduced by line 14, the asphalt containing metal contaminants being discharged bp line 18.

To increase the removal'of metals a portion ofthe deasphalted oil may be routed into settler 101 by closing valve 104 in line 17 which causes the deasphalted oil in* propane solution to flow byline 105 throughan orificetypeor other mixing devicev 100 and thence through heat' exchanger or heating means 106 into settler 101 whereby a separation is made between a lfurther asphalt phase and a deasphalted oil in propane-butane solution phase which is discharged back into line 17 through line 107. The settler 101 allows separation of the asphalt phase which is Withdrawn by line 103 and returned to the zone 11 with the wash oil.

It is desirable that a portion of the asphaltic phase including Wash oil introduced by line 102 be admixed with the deasphalted oil in propane-butane solution in line 105. To this end line 108 controlled by valve 109 is provided which allows the material in line 103 to be discharged into line 105 for admixing with the deasphalted oil solution.

It may be desirable to close off valve 109 and introduce wash oil directly into line 108 and into line 105 and this may be accomplished by closing valve 110 or throttling same and bypassing at least a portion of the wash oil from line 102 by line 111 into line 108 as may be desired.

In operations according to Fig. 5, a temperature of 150 F. and 550 pounds per square inch gauge may bc maintained in the top of tower 11, whereas the mixture introduced in settler 101 may be at a pressure of 450 pounds per square inch gauge and and at a temperature of 170 F. This is accomplished by passing the mixture through the heat exchanger 106 and by suitable adjustment of controls. By providing a pressure differential of 50 to 70 pounds per square inch gauge across the incorporator 100 or other mixing device, complete mixing is obtained. By providing a small temperature rise after mixing, the asphalt will precipitate more readily on the wash oil droplets increasing theirV size and permitting adequate settling in settler 101. The mixture of precipitated asphalt from settler 101 may be pumped as shown to the tower 11 which improves distribution due to the larger'volume of the material recycled. By main-v taining a to 20 F. temperature gradient across the -top of the tower 11, the deasphalted oil yield is adjusted to a desired level ahead of the stage comprising mixer 100 and settler 101 which reduces the amount of nickel or other metal contaminants to be removed from the deasphalted oil. This operation also serves to decrease the amount of wash oil which might be carried over into the deasphalted oil solution.

In Fig. 6 a further modifi-cation of the present invention is shown. In accordance with this modification there is provided a suitable distillation zone 120, such as a so-called vacuum still zone which is operated kat pressures of about 25 mm. to 250 mm. of mercury. A metals-contaminated petroleum feed stock fraction containing a major portion of components boiling above about 900 F. is introduced into the distillation zone 120 by line 121, the feed stock being heated at a suitable temperature such that the lighter portions thereof are ilashed olf under Ithe pressure conditions given and ascend the zone 120 in vapor form for withdrawal through an upper discharge line 122. The heavier portions of the feed stock descend to the bottom of the zone 120 for withdrawal through a lower discharge line 123. It will be understood that, if desired, the zone 120 may be lprovided with one or more side discharge lines (not shown). A suitable wash oil of the type described above is charged to the distillation zone 120 by line 124. The wash oil contacts the feed stock in zone 120 and atects a substantial removal of metal contaminants from the vaporized lighter components of the feed stock.

The vaporized lighter components of the feed stock withdrawn by the line 122 are then passed through a suitable cooler 12S for liquefaction and thence to a tower deasphalting zone 126 through a suitable distributing means 127. Propane or other liquefied, normally gaseous hydrocarbon is introduced tothe tower 126 by way of a line 128 to ow countercurrently to the 'feed stock fraction.

Deasphalted oil in solution is removed from theV upper portion of the tower 126 by way of a line 129 and after being stripped of normally gaseous hydrocarbon may be introduced as a feed stock into a catalytic cracking operation. Asphaltic components are Withdrawn through the bottom of the tower 126 through a line 130.

If desired, and sometimes preferably, a still further reduction of metal contaminants may be obtained `by charging a suitable wash oil of the type described above to the deasphalting tower through a distributing means 131 fed by a line 132 controlled by a valve 133. The conditions in the deasphalting tower 126 are those exemplied supra.

It is to be emphasized that in lconducting operations in accordance with the procedure exemplified by Fig. 6

the Wash oil should not be brought into contact with the crude residue to be decontaminated in the distillation zone while such residue is in liquid form for in this situation the wash oil may become dissolved in the crude residue and metal contaminants-removal may not be effected.

In general, it may be stated that the wash oil should be brought into contact with the metals-contaminated crude residue while such crude residue is in a nonsolubilizing ycondition with respect to the wash oil (i. e. catalytic cycle stock). This may be accomplished, for example, by adding the wash oil to the crude residue in the presence of a liquid, normally gaseous hydrocarbon (Figs. 1-5) or by adding the wash oil to vaporized crude residue or to a vaporized lighter portion thereof (Fig. 6).

From the foregoing description of the several modes of practice of the invention, it is clear that the invention maybe practiced in several Ways and the fraction of the catalytic cycle stock may be obtained vby any one of several ways from the cracked products. The fraction may be obtained by distillation, solvent precipitation, precipitation by mechanical means with subsequent distillation and/or solvent precipitation or by other reducing operations which will remove fractions boiling below 900 F.

In order to illustrate the invention further, runs were made comparing the deasphalting of crude residue from West Texas crude without employing a wash oil and while employing a fraction of catalytic cycle stock as a Wash oil. The operations are presented in Table II:

Table Il Fraction of Fraction of Wash Oil Used None Catalytic None Catalytic Cycle Cycle Stock Stock Vol. Percent Wash (Based on Residue) None 17. 2 None 17. 0 Actual DAO Yield Vol. Percent 47. 5 49. 9 60. 4 67. 2

DAO Inspections:

Sp. Gr. (S0/60 F 0.9459 0. 9190 0.9578 0.9683 Con. Carbon, Wt. Percent 3. 77 3.00 5. 27 5. 41 Agg. Ash, p. p. m 6.8 5.9 16.8 12.0 Ni Cont., p. p. m.. 1.6 0.19 3. 04 0.75 V Cont., p. p. m 2.12 0.26 4. 52 0.89 Fe Cont., p. p. m 1.17 1. 67 Percent Ni Reduction. 88. 1 75. 3

It will be seen that 88% and 75% nickel reductions were obtained, respectively, at deasphalted yields of approximately 50% and 67% with substantially all of the nickel, which is the contaminant having the major effect, being removed.

The crude residue employed as a feed stock of the present invention is the residue obtained as exemplitied by distilling crude oil to `remove the valuable components thereof. The crude oil and its residues by virtue of being in contact with earth formations, processing equipment, tanks, pipe lines, and the like, will contain various metals, such las nickel, vanadium, iron and numerous others too numerous to mention here, which deleteriously affect the catalytic activity of the catalyst in catalytic cracking operations. Since the metal contaminants eventually end up vin the crude residue, it `is desirable, as illustrated in the practice of the present invention, to remove the metal contaminants from the desirable fractions of the crude residue before using same in catalytic cracking operations. Other .metal-containing compounds such as the naturally occurring porphyrins of nickel, vanadium, iron, and the like are present as contaminants in crude petroleum and its residues and may be removed in accordance with this' invention. The present invention, therefore, has great utility in allowing valuable components of crude residue to be catalytically cracked which heretofore could not be cracked sufficiently to obtain maximum yields of desired products without formation of undesirable products, such as gas and coke.

As illustrative of crude residues suitable for treatment in the practice of the pres'ent invention and for recovery of fractions rsuitable for catalytic cracking, the following inspections are presented in Table III.

Table IIL-Feed inspections 18.9% West Texas residuum From the inspections of a typical crude residue, it will be seen that this particular residuum is contaminated with relatively large quantities of nickel, vanadium, and

' iron which deleteriously affect the catalytic cracking operation.

The present invention has wide utility and is being used commercially in removing anywhere from about 50% to 75% or more of the nickel from approximately 25,000 barrels of crude residue being charged to a deasphalting tower in which about 1600 barrels per day of a fraction of the catalytic cycle stock obtained by distilling a mixture of clarified oil and a fraction of the catalytically cracked products at a cut point of 900 to 1050 F. The procedure removes the metal contami nants down to about 0.5 part per million. The efficiency of removal of nickel and other metals and compounds thereof may be increased still further by increasing the number of stages in the deasphalting tower.

The nature and objects of the present invention having been completely described and illustrated, what I vWish to claim as new and useful and to secure by Letters Patent is:

1. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises countercurrently contacting said feed stock in a deasphalting zone with a liquefied normally gaseous hydrocarbon in simultaneous countercurrent contact with a separately introduced fraction of catalytic cycle stock under conditions to form a deasphalted oil phase substantially free from metal contaminants and an asphalt phase containing substantially all of the metal contaminants of the feed stock and separately withdrawing said phases, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to 1.2.

2. A method in accordance with claim 1 in which the fraction of the catalytic cycle stock is obtained by distillation.

3. A method in accordance with claim l in which the fraction of the catalytic cycle stock is obtained by deasphalting 4. A method in accordance with claim 1 in which the fraction of the catalytic cycle stock is obtained by a clarification and distillation operation.

5. A method in yaccord-ance with claim 1 in which the petroleum fraction contains as little as the equivalent of 1 pound of nickel metal contaminant per thousand barrels.

6. A method for treating a crude petroleum residue containing `a major portion of components boiling above 900 F. Iand contaminated with metal contaminants which comprises deasphalting said residue in ycountercurrent con- -tact with a liquefied normally gaseous hydrocarbon in a deasphalting zone while simultaneously countercurrently contacting said residue with a separately introduced fraction of catalytic cycle stock under conditions to form a deasphalted oil phase and an asphalt phase, and recovering said deasphalted oil phase, said Icatalytic cycle stock being obtained by catalytic cracking of la gas oil fraction of crude petroleum .and said deasphalted oil phase, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2.

7. A method in accord-ance with claim `6 in which the lfraction of the catalytic cycle stock is obtained by distillation.

8. A method in accordance with claim 6 in which the fraction of the catalytic cycle stock is obtained by detasphalting.

9. A method in accordance with claim 6 in which the fraction of the catalytic cycle stock is obtained by a clarification and distillation operation.

10. A method in accordance with claim `6 in which the petroleum fraction contains as little as the equivalent of 1 pound of nickel metal contaminant per thousand barrels.

11. A method in accordance with claim 6 in which the crude petroleum residue is obtained from the crude petroleum from which the gas oil fraction is obtained.

12. A method for treating a Ipetroleum fraction feed stock containing `a major portion of components boiling yabove 900 F. and contaminated by a substantial amount of metal contaminants which comprises introducing said Afeed stock into a deasphaltng zone comprising a plurality of stages and there countercurrently contacting said feed stock with a liquefied normally gaseous hydrocarbon in simultaneous countercurrent contact with a separately introduced fraction of catalytic cycle stock under conditions -to form a deasphalted oil phase substantially free from metal contaminants Vand an asphalt phase containing substantially all of the :metal contaminants of the feed stock and separately withdrawing said phases, said conditions encompassing a temperature gradient between said stages with the -highest temperature at the stage adjacent the point of withdrawal of said deasphalted oil phase, said lfraction of catalytic cycle stock having a specific gravity within the range from about 1.05 to 'about 1.2.

13. A method 4for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of :metal contaminants which comp-rises vapo-rizing at least a portion `of said feed stock, countercurrently contacting said vapors with a fraction of catalytic cycle stock .to substantially extract metal contaminants from said vapors, collecting and liquefying the thus contacted vapors, deasphalting the thus vcollected liquid -by countercurrently contacting the same with a liquefied normally gaseous hydrocarbon under conditions to for-m a deasphalted oil phase and an asphalt phase and recovering the deasphalted oil phase, said 4fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2. A

14. A method for treating a lpetroleum fraction feed stock containing a major portion Iof components boiling r r 1 l l above 900 F. and contaminated by a substantial amount of metal contaminants which comprises vaporizing at least a portion of said feed stock, countercurrently contacting said vapors with a fraction of catalytic cycle stock to substantially extract metal contaminants from said vapors, collecting and liquefying the thus contacted vapors, deasphalting the thus collected liquid by countercurrently contacting the same with a liquefied normally' gaseous hydrocarbon and a -further quantity of said catalytic cycle stock under conditions to form a deasphalting oil phase and an asphalt phase, and recovering the deasphalted oil phase, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2.

15. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises introducing said feed stock into a deasphalting zone and there countercurrently contacting said feed stock with about 2 to l volumes per volume of feed stock of a liquefied normally gaseous hydrocarbon and also simultaneously countercurrently contacting said feed stock in said deasphalting zone with a separately introduced fraction of catalytic cycle stock under conditions to form a deasphalted oil phase substantially free from metal contaminants and an asphalt phase containing substantially all of the metal contaminants of the feed stock and separately withdrawing said phases, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2.

16. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises introducing said feed stock into a deasphalting zone and there countercurrently contacting said feed stock with about 2 to l0 volumes per volume of feed stock of a liquefied normally gaseous hydrocarbon and also simultaneously countercurrently contacting said feed stock in said deasphalting zone with a separately introduced fraction of catalytic cycle stock under conditions to form a deasphalted oil phase substantially free from metal contaminants and an asphalt phase containing substantially all of the metal contaminants of the feed stock and separately withdrawing feed phases, said catalytic cycle stock being obtained by catalytic cracking of a mixture of a gas oil fraction of crude petroleum and said deasphalted oil phase, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2.

17. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises introducing said feed stock into a deasphalting zone comprising a plurality of stages and there countercurrently contacting-said feed stock with about 2 to 10 volumes per volume of feed stock of a liquefied normally gaseous hydrocarbon and also simultaneously countercurrently contacting said feed stock in said deasphalting zone with a separately introduced fraction of catalytic cycle stock under conditions to form a deasphalted oil phase substantially free from metal contaminants and an asphalt phase containing substantially all of the metal contaminants of the feed stock and separately withdrawing said phases, said conditions encompassing a temperature gradient between said stages, with the highest temperature at the stage adjacent the point of withdrawal of said deasphalted oil phase, said fraction of catalytic cycle stock having a sepcilic gravity within the range from about 1.05 to about 1.2.

18. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises vaporizing at least a portion of said feed stock, countercurrently con" tacting said vapors with a fraction of catalytic cycle stock to substantially extract metal contaminants from said vapors,v collecting and liquefying the thus contacted vapors, deasphalting the thus collected liquid by contacting the same with about 2 to l0 volumes per volume of collected liquid of a liquefied normally gaseous hydrocarbon under conditions to form a deasphalted oil phase andan asphalt phase and recovering the deasphalted oil phase, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.2.

19. A method for treating a petroleum fraction 'feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metal contaminants which comprises Vaporizing at least a portion of said feed stock, countercurrently contacting said vapors with a fraction of catalytic cycle stock to substantially extract metal contaminants from said vapors, collecting and liquefying the thus contacted vapors, deasphalting the thus collected liquid by countercurrently contacting the same in a deasphalting zone with about 2 to 10 volumes per volume of collect-ed liquid ofY fraction of catalytic cycle stock having a specific gravityy within the range of about 1.05 to about 1.2.

20. A continuous method for treating a metals contaminated petroleum fraction feed stock containing la major portion of components boiling above 900 F. in

a deasphalting tower which comprises the steps of continuously introducing a liquefied normally gaseous hydrocarbon into said tower adjacent the lower end thereof, continuously introducing said feed stock into said tower above the point of introduction `of said liquefied hydrocarbon, continuously introducing into said tower -above the point of introduction of said feed stock a primary asphaltic wash material, said primary wash material hav- .ing been obtained by continuously withdrawing a first solution of deasphalted oil in said liquefied hydrocarbon from the top of said deasphalting tower, continuously adding a wash oil to at least a portion of said first solution and intimately mixing said wash oil with said portion of said first solution in a mixing zone to provide a second solution, lcontinuously resolving said second solution into an asphalt phase and a solution of deasphalted loil in said liquefied hydrocarbon in a settling zone and continuously recycling said asphalt phase from said settling zone to said deasphalting tower as said primary Wash material, withdrawing an asphalt phase from the bottom of said deasphalting tower and recovering a solution of deasphalted oil in said liquefied hydrocarbon from said settling zone, said wash oil consisting of a fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to about 1.08.

2l. A method as in claim 20 wherein said deasphalting tower is operated to provide for a pressure of about 450 p. s. i. g. and a temperature of about F. at the top thereof, and wherein a pressure differential within the range of about 50 to 70 p. s. i. g. is maintained across said mixing zone, with the lower pressure being at the outlet end of said mixing zone.

22. A method for treating a petroleum fraction feed stock containing a major portion of components boiling above 900 F., and contaminated by a substantial amount of metal contaminants which comprises contacting said feed stock in a deasphalting zone with a liquefied normally gaseous hydrocarbon solvent under conditions to form an asphalt phase and a solution of deasphalted oil in said solvent, contacting said solution of deasphalted -0il with a fraction of catalytic cycle stock and recovering 13 a deasphalted oil substantially free from metal contaminants from said solution, said fraction of catalytic cycle stock having a specific gravity within the range of about 1.05 to 1.2.

References Cited inthe file of this patent UNITED STATES PATENTS 1,978,361 Beiswenger Oct. 23, 1934 14 Lindeke et a1. Sept. 8, 1936 Jewellv June 29, 1943 Knox Ian. 25, 1955 Hennig Dec. 20, 1955 Webber May 21, 1957 Corneil et al May 21, 1957

Claims (1)

1. A METHOD FOR TREATING A PETROLEUM FRACTION FEED STOCK CONTAINING A MAJOR PORTION OF COMPONENTS BOILING ABOVE 900*F. AND CONTAMINATED BY A SUBSTANTIAL AMOUNT OF METAL CONTAMINANTS WHICH COMPRISES COUNTERCURRENTLY CONTACTING SAID FEED STOCK IN A DEASPHALTING ZONE WITH A LIQUEFIED NORMALLY GASEOUS HYDROCARBON IN SIMULTANEOUS COUNTERCURRENT CONTACT WITH A SEPARATELY INTRODUCED FRACTION OF CATALYST CYCLE STOCK UNDER CONDITIONS TO FORM AA DEASPHALTED OIL PHASE SUBSTANTIALLY FREE FROM METAL CONTAMINANTS AND AN ASPHALT PHASE CONTAINING SUBSTANTIALLY ALL OF THE METAL CONTAMINANTS OF THE FEED STOCK AND SEPARATELY WITHDRAWING SAID PHASES, SAID FRACTION OF CATALYTIC CYCLE STOCK HAVING A SPECIFIC GRAVITY WITHIN THE RANGE OF ABOUT 1.05 TO 1.2.

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