US2793168A - Method for solvent deasphalting of residual oil - Google Patents

Description

May 21, 1957 H. G. CORNEIL ET AL 2,793,163

METHOD FOR SOLVENT DEASFHALTING OF RESIDUAL OIL Filed Oct. 15, 1954 Propane Hawkins Residual Oil l4 Propane solution A "-0f cracking stock free from metallic contaminants.

Residual charge containing metallic contaminants.

Asphalt containing metallic contaminants FIG. I.

Residual charge Hawkin's residual oil Propane FIG. 2.

INVENTORS.

Hampton 6. Cornell, BY Gilmore T- 6win,

Paul E Korbach,

METHOD FGR SQLVE'NT DEASPHALTING OF RESIDUAL OIL Hampton G. Corneil and Gilmore T. Gwin, Baytown, Tex., and Paul F. Korbach, Shellield, Ala., assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware Application October 15, 1954, Serial No. 462,440

7 Claims. (Cl. 196-1446) The present invention is directed to a method of removing ash contaminants from residual petroleum fractions.

Substantially all of the crude petroleum oils commercially processed contain substantial amounts of ash. An important part of this ash consists of metallic contaminants of the type of nickel, vanadium and iron. The residual oils resulting from the disillation of such crude oils contain such an amount of ash including such metal contaminants as to be undesirable feed stock for catalytic cracking operations. These contaminants may be removed to a great extent by deasphalting, such as with liquefied normally gaseous hydrocarbons. This invention is based on the discovery that the overall removal of metal contaminants is greater when a mixture of a low asphalt containing residum and residuum derived from crude oil from the Hawkins field in Texas is deasphalted than when the two residua are deasphalted separately to the same total deasphalted oil yield.

The present invention may briefly be described as contacting a residual petroleum fraction containing ash in a deasphalting zone with at least a portion of residual oil derived from Hawkins crude and liquefied gaseous hydrocarbon to form a deasphalted oil having a substantially reduced ash content and desirable as a feed stock for catalytic cracking.

More specifically the present invention is directed to a procedure whereby a residual petroleum fraction, that is a fraction containing a major portion of components boiling above 900 F. and contaminated with a substantial amount of ash including metal contaminants which have as their origin metal contaminants present in, the crude oil as produced from the earth, is treated to secure a fraction having a low :ash content. The treating step is carried out by contacting in a deasphalting zone the residual oil, at least a portion of residual oil derived from Hawkins crude free from constituents boiling below approximately 650 F., and liquefied normally gaseous hydrocarbon to form in the deasphalting zone a deasphalted oil phase with a substantially reduced ash content and an asphalt phase containing a large part of the ash of the feed stock and separately withdrawing said phases from said deasphalting zone. The resultant deasphalted oil phase with low ash content is a desirable feed stock for a catalytic cracking process whereas the residual oil with metal contaminants, which is the charge stock for said deasphalting zone, is an undesirable feed stock for a catalytic cracking process.

The residual oil derived from a crude petroleum from the Hawkins field in Texas may be described generally as an oil derived from Hawkins field crude free from components boiling below about 650 F. Characteristics of Hawkins residual oils suitable for use as the wash oil in a process of the present invention, are set out hereafter in Table I:

States Patent Patented May 21, I957 2 TABLE I Typical wash oil inspections The present invention will now be described in greater detail in conjunction with thedrawing in which Fig. 1 is in the form of a diagrammatic flow sheet illustrating one procedure, for carrying out the deasphalting step for removing metallic contaminants from the residual charge stock; and,

Fig 2 is in the form of a diagrammatic; flow sheet illustrating another procedure for deasphalting the residual feed stockfor removing metallic contaminants therefrom.

Turning now specifically to the drawing and first to Fig. 1, the deasphalting step. is carried out in vessel A. A residual. fraction having ash containing metallic contaminants derived from. a crude oil is charged through inlet line 11 and in the line has admixed therewith a Hawkins residual oil through inlet line 12 andliquefied normally gaseous hydrocarbon such as propane introduced through inlet line 13. The admixture of residual charge oil, Hawkins residual oil and propane passes into settling vessel A where two phases are allowed to separate by gravity settling. From drum A a propane solution of oil with a greatly reduced ash content and particularly suitable as the charge stock for a catalytic cracking step is withdrawn through line 14. and an asphalt fraction containing ash constituents is withdrawn through outlet line 15.

It will be understood that Fig. l is schematic only and that various auxiliary equipment well known to a workman skilled in the art will be used for performing additional Well known steps in the process as, for example, the recovery of propane from the fractions withdrawn through outlet lines 14 and 15 for further use in the system.

An alternative procedure for removing metallic contaminants from a residual fraction of crude oil is shown in Fig. 2. In Fig. 2 an asphalt settling drum B is provided. The residual charge stock having ash containing metallic contaminants derived from crude oil is charged to settling drum B by way of inlet line 20, a fraction of Hawkins residual oil is introduced to drum B by way of inlet line 21 and a liquefied normally gaseous hydrocarbon is introduced into drum B through inlet line 22. In drum B a phase separation takes place with the phases separating under the influence of gravity. A propane solution of oil with a greatly reduced ash content and suitable as the charge stock to a catalytic cracking process is withdrawn through outlet line 23 and an asphalt fraction containing ash contaminants is withdrawn through outlet line 24. As explained in conjunction with Fig. 1, Fig. 2 is schematic only and auxiliary equipment such as means for recovering the propane from the fractions withdrawn through outlet lines 23 and 24 will be provided for recovering propane for further use in the systern.

The inspections of residua from the distillation of typical crude oils charged to refinery operations are set out hereafter in Table II. In Table II, columns 1, 2, 3, and 4 show the characteristics respectively of residua derived from a mixture of Gulf Coast and West Texas crudes, a West Texas crude, a Panhandle crude and a Lagunillas crude.

3 TABLE 11 Typical feed stock inspections The catalytic cracking of fractions of petroleum oils is well known to the art. A description of such a catalytic cracking process may be found in U. S. Patent 2,587,554, issued February 26, 1952, in the name of John Weikart. In such catalytic cracking operations it has been found that if the charging stock contains appreciable amounts of ash including metal contaminants, such as three pounds of nickel per thousand barrels of charge stock, the catalytic cracking process is adversely afiected. Other metal components such as vanadium and iron are undesirable but are less troublesome than nickel; in general, on a weight basis it may be considered that vanadium is perhaps as troublesome as nickel and iron is perhaps /2 as troublesome as nickel.

In carrying out the deasphalting step in the present invention where a Hawkins residual oil is introduced into the deasphalting zone to serve as a selective solvent for the ash including metal contaminants whereby the ash is removed selectively from the residual charge stock, the solvent used is a liquefied normally gaseous hydrocarbon. The use of liquefied normally gaseous hydrocarbon for deasphalting is well known. As specific examples of materials which may be used may be mentioned ethane, propane, propylene, butylene, butane and mixtures thereof. Because of pressure limitations in the operating equipment, it is preferred to use butane, propane, propylene and butylenes or mixtures thereof with a desirable commercial mixture consisting of 30% butane and 70% propane.

The amount of Hawkins residual to be employed will be at least about 5% by volume of the mixture of residua in the deasphalting zone. Excellent results have been achieved with amounts in the range of 20% to about 50% Hawkins residual.

The preferred amount of solvent employed in the deasphalting step is within the range of about 2 to about volumes of solvent per volume of Hawkins residual oil charged to the deasphalting step. As a specific example, 3 volumes of solvent per volume of residual oil charged is a desirable commercial ratio.

The temperature at which the deasphalting step is conducted may be within the range of about 100 to about 300 F. As a specific example, a temperature of about 150 F. is desirable. Pressures sufficient to provide a liquid phase are employed.

In order to illustrate further the advantages of the present invention, the following example is given:

EXAMPLE A Hawkins residual oil consisting of 29% bottoms from a pipe still charging straight Hawkins crude is designated hereafter in Table III as residuum A. A mixture designated hereafter in Table III as residuum B was made up consisting of the following percentages.

20% Heavy Coastal Mixed Sweet 6% Tomball 15 Mixed Sweet-Light West Texas Mixture 43 West Texas-Salt Flat Mixture Residuum A was separately deasphalted, residuum B was separately deasphalted and equal parts of residua A and B in admixture were deasphalted. These results are 4 reported in columns 1, 2, and 3, respectively, in Table III. In column 4 the results obtained by separately deasphalting oils A and B and combining the deasphalted products are given:

TABLEIII Residuum A B A+B (Equal A-l-B Sep- Parts). arate. Type of Processing In Mixtures... Deasphalted Oil Yield, 32 71 52 52.

Vol. Percent. Deasphalted Oil Quality, 4.0 4.0 4.0 4.0.

Conradson Carbon, Wt. Percent. Ash, Lbs./1000Bbls 1.3 6.9 3.0 5.2. Nickel, Lbs/1000 Bbls- 0.7 0.3

1 A= Pure Hawkins resld; 29% bottoms from pipe still charging straight Hawkins crude.

1 Too low to measure.

It will be noted from the example that by carrying out the deasphalting step of the residual oil in the presence of Hawkins residuum as a selective solvent for the ash that the deasphalted oil resulting has a much lower ash content than is obtained when the residual oil is deasphalted without having Hawkins residual present in the deasphalting zone.

While specific examples have been given illustrating the practice of the present invention, it will be understood that these specific examples are given by way of illustration only and not by Way of limitation.

' The invention claimed 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 ash including metallic contaminants consisting of contacting said fraction in a deasphalting zone with at least a portion of a residual oil derived from Hawkins crude free from constituents boiling below approximately 650 F. and with liquefied normally gaseous hydrocarbon under conditions to form in said deasphalting zone a deasphalted oil phase having a substantially reduced content of ash and metallic contaminants and an asphalt phase containing a major portion of ash constituents introduced into said deasphalting zone and separately withdrawing said phases from said deasphalting zone.

2. A method in accordance with claim 1 in which the contaminated petroleum fraction is contacted with an amount in the range from about 5% to about 50% by volume of the residual oil derived from Hawkins crude.

3. A method in accordance with claim 1 in which the conditions include a temperature within the range of about to about 300 F., pressures suflicient to provide a liquid phase and a ratio of liquefied normally gaseous hydrocarbon to Hawkins residual oil in the range from about 2 to about 10 volumes to one volume.

4. A method in accordance with claim 1 in which the liquefied normally gaseous hydrocarbon is a mixture of propane and butane.

5. A method for treating an asphalt-containing petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metallic contaminants which comprises deasphalting said feed stock with a liquefied normally gaseous hydrocarbon in the presence of a resid ual fraction derived from a Hawkins crude, said Hawkins residual crude fraction being substantially free from constituents boiling below approximately 650 F.

6. A method for treating an asphalt-containing petroleum fraction feed stock containing a major portion of components boiling above 900 F. and contaminated by a substantial amount of metallic contaminants which comprises admixing said feed stock with a residual fraction derived from a Hawkins crude and with a liquefied normally gaseous hydrocarbon, charging said mixture to a settling zone to obtain phase separation, withdrawing a lighter phase comprising a solution in said liquefied hydrocarbon of a solvent oil having a substantially reduced content of metallic contaminants and separately withdrawing from said settling zone an asphalt phase containing a major portion of the metallic contaminants charged to said settling zone, said Hawkins residual fraction being substantially free from constituents boiling below approximately 650 F.

7. A method for treating an asphalt-containing petroleum fraction feed stock containing a major portion of components boiling above 900' F. and contaminated by a substantial amount of metallic contaminants which comprises charging said feed stock, a liquefied normally gaseous hydrocarbon and a residual fraction derived from a Hawkins crude to a settling zone under conditions to form a lighter phase and a heavier phase, withdrawing a lighter phase comprising a solution in said liquefied hydrocarbon of a solvent oil having a substantially reduced content of metallic contaminants and separately withdrawing from said settling zone an asphalt phase containing a major portion of the metallic contaminants charged to said settling zone, said Hawkins residual fraction being substantially free from constituents boiling below approximately 650 F.

References Cited in the file of this patent UNITED STATES PATENTS 2,009,710 Goodwin July 30, 1935 2,041,276 Bray May 19, 1936 2,053,485 Lindeke et a1. Sept. 8, 1936 2,727,853 Hennig Dec. 20, 1955 2,729,589 Waghorne et al. Jan. 3, 1956

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 ASH INCLUDING METALLIC CONTAMINANTS CONSISTING OF CONTACTING SAID FRACTION IN A DEASPHALTING ZONE WITH AT LEAST A PORTION OF A RESIDUAL OIL DERIVED FROM HAWKINS CRUDE FREE FROM SONSTITUENTS BOILING BELOW APPROXIMATELY 650* F. AND WITH LIQUEFIED NORMALLY GASEOUS HYDROCARBON UN-

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