US2375694A - Process of refining hydrocarbon oil for the purpose of removing metal ions - Google Patents

Description

May 8, 1945.

STORAGE TANK H. cs; SCHUTZE 2,375,694 PROCESS, OF REFINING HYDROCARBON OIL FOR THE PURPOSE OF REMOVING METAL IONS Filed Dec. 2, 1941 Patented May 8, 1945 PROCESS OF REFINING HYDROCARBON OIL FOR. THE PURPOSE OF REMOVING METAL IONS Henry G. Schutze, Baytown, Tex., assignor to Standard Oil' Development Company, a corporation of Delaware Application December 2, 1941, Serial No. 421,269

9 Claims.

The present inVentiOn relates to improvements in refining of hydrocarbon oil, and more particularly it relates to improvements in the art of removing from refined hydrocarbon oils small quantities of metals and metal ions which are present therein following refining operations.

An important application of my present invention relates to removing from the residuums resulting from the process of preparing lubricating oil from a reduced crude as, for example, described in the co-pending application of Reuben F. Pfennig, et al., which has issued "as Patent No. 2,339,875, January 25, 1944, in which application there is described and claimed a method of treating a reduced crude with fused caustic soda, and thereafter discharging themixture into a separation zone where the caustic soda and the oil stratify, thence removing the upper oil layer, and distilling from it the color stable lubricating oil. The residuums of the distillation operation are ordinarily employed as a bunker fuel or the like. In the type of operation described in the aforesaid application, however, the residuums from the distillation operation contain appreciable quantities of sodium compounds which, when present in the oil, would cause various difi'iculties in the furnace in which they were burned as a fuel. Consequently, it is necessary to remove substantially all of these sodium ions and my present invention, as hereinbefore indicated, provides suitable means for removing these ions.

In treating the residuums aforementioned, or other hydrocarbon oils containing sodium compounds, I cause the residuums to flow through an elongated bed of an acid reacting material which may be prepared, for example, by the methods described in U. S. Bureau of Mines Report of Investigations No. 3559, of March 1941, or other materials such as those derived from the residues resulting from treating hydrocarbon oil with sulfuric acid to form a sludge, which sludge is then coked by heating, and thereafter treated at elevated temperatures with sulfuric acid, as described in the co-pending application of Joseph John Savelli, which has issued as Patent No. 2,337,500, December 21, 1943.

For better understanding of my invention, reference is made to the accompanying drawing which shows'diagrammatically a form and arrangement of apparatus elements in which my invention may be carried into practical effect. The residuums resulting from the preparation of the lubricating oil by treatment of a reduced crude with fused caustic soda, hereinbefore referred to, is introduced into the system through line I, thence dischargedinto a fired coil 3, disposed in a furnace 5 in which the oil is heated to a temperature of 350 F. or any suitable temperature which will reduce the viscosity of the oil such as to make it readily fiowable. Alternatively or in addition, the viscosity of the residuum may be reduced by fiuxing with kerosene, gas oil, or the like by introducing the fluxing medium into line I by means of line 2. Thereafter the oil is discharged into an elongated vertical treating tower 10 near the top thereof. The tower l0 contains a continuous bed of the aforementioned carbonaceous ion exchange material C. The oil flows through the bed of carbonaceous material and during its assage therethrough substantially all of the sodium ions contained therein are removed by the ion exchange material. The oil is fed to the treating tower at a rate of about 4 V/V/hour, The treated oil is withdrawn through line I5 and delivered to storage tank 20.

During the operation which I have just nowdescribed, there comes a time when the carbona-' or revivified. Obviously, the onstream period is dependent upon the amount of sodium originally contained in the oil. The oil may contain from about 0.1 to 1%, but usually it is in the neighborhood of about 0.2% of sodium measured as sodium hydroxide. Where the untreated oil contains about 0.2% by weight of sodium, the oil may be maintained on the onstream operation for a period of from about 60 to 120 hours, where one volume of oil per volume of ion exchange material is fed to the tower per hour.

As previously indicated, therefore, there comes a time when the treating agent must be revivified and this is preferably accomplished by discon tinuing the flow of oil to the treating tower and. in the case of a heavy oil, first flushing the treat ing agent with a suitable substance, such as kerosene, to remove the residual oil. This flushing oil may be pumped from pipe 25 through pipe 15 upwardly through the bed of treating material and withdrawn verhead through line 22. After the flushing oil is withdrawn, the regeneration proper is carried out by pumping from line 25 tion for a sufficient period of time to remove all of the acid from the treating material and then titrating back the excess sodium hydroxide with standardized acid.

It should be stated that the particle size most practical to employ with respect to the treating material is one within the range of from about 10 to 30 mesh.

Another important adaptation of my invention involves removing the residual copper from hydrocarbon oils, such as gasoline, kerosene, light gas-oil, etc., by the so-called copper sweetening process. In the copper sweetening of hydrocarbon oils, the sour oil containing mercaptans and other undesirable sulfur compounds is contacted in liquid phase with a clay impregnated with cupric chloride in the presence of an oxidizing gas, such as air or oxygen. In a similar copper sweetening process, the sour oil is treated with a solution containing copper ions.

Both of these processes are subject to the objection that minor amounts of copper compounds are contained in the treated oil. These minor amounts of copper are-highly objectionable [because they accelerate gum formation and also accelerate the production of color forming bodies. Prior to my invention it has been proposed by others to remove these minor amounts of copper compounds .by treating the sweetened oil with sodium sulfide or other salt. As indicated previously, another modification of my invention involves treating copper sweetened hydrocarbon oils by passing them through an elongated bed of the carbonaceous ion exchange materials hereinbefo-re referred to, whereupon the copper compounds are removed from the oil.

EXAMPLE 1 In a run which I made, I treated gasoline containing 3 parts per million of copper at ordinary temperatures and pressure for a period of 5 minutes, and the treated oil was placed in storage for inspection along with a blank, with the fol-' lowing results:

Table 1 Motor fuel containing 3 P. P. M. of copper ion and percolated through carbonaceous ion exchange material Motor fuel containing 3 P. P. M. ofcopper 1011 Storage period,

AS'IM Designation: ID525-40T. ASTM Standards 1940 Supplement, part III, page 211.

EXAMPLE 2 A residuum resulting from the distillation of a crude petroleum oil was treated with fused alkali as hereinbefore described and then was fluxed with cracking coil tar (to reduce the viscosity of the former) in the proportion of 2 parts of tar to 1 part of residuum. The fluxed residuum was tested and found to have the following characteristics:

Table 2 Gr. API 14.5 Open cup fiash F 355 Vis. at 210 F., SSU 214 Alkalinity expressed as wt. per cent NaOH 0.20

The fiuxed oil was then percolated through a filter containing a carbonaceous ion exchange material sold under the trade name of Zeo-Karb H. The filter was approximately 1 inch in diameter and about 24 inches long and was fitted at its lower end with a rate control valve. A vacuum filter flask connected to the bottom of the filter served as a receiver for the oil. The fluxed oil was introduced into the top of the filter and percolated therethrough at a temperature of 350 F, with application of vacuum to assist in the operation. The oil collected in the filter flask was cooled and tested. The following results indicate removal of sodium ion from the fluxed residuum by the above-described treatment:

Table 3 EXAMPLE 3 The carbonaceous ion exchange material remaining after treatment of the oil as described in Example 2 was regenerated by washing with naphtha to remove heavy oil remaining in the ion exchange bed and, after drying, agitating mechanically with an excess of sulfuric acid of 50% by weight concentration for 3 to 4 hours at room temperature. The mixture of acid and ion exchange material was allowed to stand for about 16 hours; the acid was separated, and the ion exchange material was then washed free from acid with water. The regenerated carbonaceous ion exchange agent was dried and was employed to treat additional quantities of the fluxed oil described in Example 2. In a like manner, the ion exchange material remaining after treating the second quantity of oil was regenerated and employed to treat a third portion of oil. Similarly the ion exchange material was regenerated after the third treatment of oil and was employed to treat a fourth quantity of fluxed oil and thereafter was again regenerated and employed to treat additional quantities of oil. The following data illustrate the effectiveness of the regenerated carbonaceous ion exchange material in removing alkalinity from fluxed crude residuum:

Table 4 Alkalinity of Vol. of oil Alkalinity of charge oil, expercolated percolated Percolation agent pressed as per vol. of oil, expressed Weight per Zeo-Karb as weight per cent NaOH H charged cent NaOH Zeo-Karb H," 1st regen 0. 20 22.0 0. 068 Zeo-Karb H, 2nd regen 0. 2D 12. 5 0. 09 Zeo-Karb H, 3rd regen 0. 20 12. 6 0. 089 Zeo-Karb H, 4th regen 0. 20 12. 0 0. 086

The above data clearly show the carbonaceous ion exchange material may be regenerated by treatment with dilute sulfuric acid and that said regenerated material is an effective treating reagent in removing metallic ions such as sodium ions from petroleum oils.

To recapitulate, my present invention relates to improvements in the art of refining hydrocarbon oil and, in particular, to removing metals such as sodium, which may be present in a lubricating oil in substantial amounts as a result of the manufacture of the oil employing fused caustic soda, or copper, which may result in formation of an unstable gasoline, Diesel fuel, kerosene, or the like as a result of treating such hydrocarbon oil by the so-called copper sweetening method. The basic concept of my invention involves removing these metals by contacting the hydrocarbon oil with an acid-reacting carbonaceous material produced by treating with stron sulfuric acid vegetable material, certain mineral materials such as lignite, or various sludges resulting from refining hydrocarbon oils with strong sulfuric acid.

Many modifications of my invention will readily suggest themselves to those who are familiar with this art Without departing from the spirit thereof.

The present invention having been thus described and illustrated, what is claimed as new and useful and is desired to be secured by Letters Patent is:

1. In the refining of petroleum oil, the improvement which comprises contacting said oil with an acid reacting carbonaceous ion exchange material prepared by coking an acid sludge followed by treatment of said acid sludge with concentrated acid at high temperature whereby the metal ions contained in the said oil are at least in substantial quantity removed therefrom.

2. The process set forth in claim 1 in which the oil to be treated is a heavy residual oil and the ion to be removed is sodium.

3. The process set forth in claim 1 in which the oil to be treated is a copper sweetened oil and the metal ion to be removed is copper.

4. The process of refining hydrocarbon oils for the purpose of removing metal ions contained therein in minor quantities, which comprises continuously contacting the said oil with an acid reacting carbonaceous ion exchange material prepared by coking an acid sludge followed by treatment of said acid sludge with concentrated acid at high temperature in a treating zone for a sufficient period of time to effect the desired improvement, and recovering the treated oil.

5. The process set forth in claim 4 in which the acid reacting carbonaceous ion exchange material is periodically revivified by treatment with an acid.

6. In the production of a fuel oil of improved quality from a charging stock containing from 0.1 to 1% of sodium, the improvement which comprises causing the charging oil to flow by gravity through an elongated bed of an acid reacting carbonaceous ion'exchange material prepared by coking an acid sludge followed by treatment of said acid sludge with concentrated acid at high temperature and recovering the fuel oil from said carbonaceous material.

'7. The process set forth in claim 6 in which the charging oil is diluted with a relatively lower boiling hydrocarbon oil in order to reduce the viscosity thereof.

8. In the process of refining motor fuels which have been sweetened by the copper sweetening method, the improvement which comprises continuously flowing the sweetened oil through an elongated zone of an acid reacting carbonaceous ion exchange material and recovering the improved gasoline.

9. In the refining of a copper sweetened oil for the removal therefrom of copper ions the improvement which comprises contacting said oil with an acid reacting carbonaceous ion exchange material whereby the copper ions in the said oil are at least in substantial quantity removed therefrom.

HENRY G. SCHUTZE.

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