US1709203A - Process of purifying petroleum oils - Google Patents

Description

Patented Apr. 16, 1'929.

UNITED STATES 1,709,203 PATENT. OFFICE.

JOHN C. BLACK, OF DESTREHAN, LOUISIANA, AND WIRT D. RIAL AND RAYMOND '1.

HOWES, OF WILMINGTON, CALIFORNIA," ASSIGNORS TO PAN AMERICAN PETRO- LEUM COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

PROCESS OF. PURIFYING PETROLEUM OILS.

No Drawing.

Our invention relates to the treatment of petroleum oils to purify same and 1t has particular reference to the purlficatlon of petroleum hydrocarbons ofthose substances com- 5. pounds or natural ingredients which 1I 1 the presence of water, alkaline or salt solut1ons, tend to emulsify the oil and the prlme object of our invention is treating hydrocarbon 011s, especially of the western classes, to refine same by the removalv of emulsifying compounds, such as soap forming compounds, and acids, the presence Of'WlllCl'l 1s the zhief cause for the formation of the undesirable emulsions.

As a general rule emulsifiable compounds in any oil are objectionable, but th 1s 1s especially true of certain lubricating 011s, as turbine oils, which, with admixture of water or aqueous solutions are requlred to reslst emulsification. It has been, and is now, ex-

tremely difi'icult so to refine a western petroleum oil that it will meet this requirement. There exist in these oils, ingredients, compounds and substances which lend themselves naturally to emulsification, and very frequently these emulsions are formed during refining operations. They are extremely d1fficult to destroy or break down and are responsible for high treating losses and costly 3 equipment tie-ups.

The alcoholic treatment is one that is fre.

quently employed to rectify this condition and remove those naturally inherent constituents of petroleum oil which bring about this condition of emulsification. While this alcoholic treatment is satisfactory to a large degree, it is too expensive for general use, and the essential purpose of our invention is to provide an economical process for treating hydrocarbon oils by which all soap forming compounds'and in fact all emulsion producing and forming substances may be wholly removed from. the oil. y

We have discovered that it is possible to convert the soap forming compounds and petroleum acids into a sodium soap and that after a. partial removal of the sodium soap, a final and complete removal of it may be effected by or in the presence of hydrates of an alkaline earth metal, in accordance with thesteps as detailed hereinafter.

Lubricating oil is first subjected to a treatment with a relatively weak caustic soda solution, or approximately 2 to 5'B., and pro- Application filed April 26,

portioned in excess of the quantity needed completely to act with all petroleum acids or sified conditions of the oil, be they soap forming substances or otherwise. Our experience shows that approximately a proportion of ten percentum of the caustic soda solution is enerally correct for the purposes mentioned, but it will be understood that .this proport on may vary according to the amount and to the character of the compounds or substances or ingredients which are susceptible to emulsification in the particular oil under treatment. So also may the strength vary in proportion as the character of the oil varies, 1t belng generally observed in our experience that the heavier the oil is, the more dilute should be the caustic soda used, its quantity however being in an inverse ratio.

After having first treated the oil with the caustic soda solution, the mixture of the oil and caustic soda solution is subjected to a pressure of from fifty to one hundred pounds, in a closed retort of any construction and preferably insulated to maintain heat, live steam being employed to agitate the mixture 1n order to bring about as complete a reaction as possible between the caustic soda and the compounds or ingredients of the oil, that are to be removed. 1

After sufiicient treating in this manner, the agitation with steam is discontinued and the mixture allowed to stratify in accordance with the specific gravities of the components of the mixture. The aqueous stratum or por t1on of the mixture is then withdrawn, and the oil is subjected thereupon to hot water washes to remove the caustic soda and the soap forming substances released thereby from their association with the oil. By this treatment a removal of substantially all of the soap, and

soap forming substances is accomplished. 1

scribed. These compounds we have found to remain inthe oil treated as outlined-in suiiicientquantities to cause an emnlsification of the oil whenmixed and agitated with aqueous caustic soda, salt or alkaline solutions. We have discovered that these emulsifying sub stances may be acted upon to form compounds which may be readily removed. For the purpose of converting these emulsifying agents into compounds which may be separated from the oil, We find that alkaline earth metal hydroxides are particularly adaptable, because they combine with or absorb readily the sodium soap compounds in the oil and other emulsifying constituents, such as gums, resins and other products of polymerization, to form other compounds which may be readily separated from the oil, and these alkaline earth metals are available in unlimited quantities at reasonable cost. Of the alkaline earth metal hydroxides, which are usable for the purposes, we prefer calcium in the form of hydrate, though barium hydrate and magnesium hydrate may be employed with satisfactory results. The alkaline earth metal hydroxide used is mixed with the oil that has been previously treated for the purification thereof and still contains the undesirable emulsifying bodies. The-compounds resulting from the action or reaction of the introduced hydrate, which we prefer to be calcium hydrate, in physical characteristics are gelatinous, and being somewhat soluble in the oil, cannot be separated by filtration for this reason. To overcome this objection We mix with oil and calcium hydrate'a desirable quantity of any of the well known filtering clays or infusorial earth, whereby the said soaps are extracted by adsorption, i

In practicing the invention, the mixture of oil, (previously treated as explained), filtering clay, infusorial earth or diatomaceous earth-and calcium hydrate is subjected to a temperature at which expulsion of the water content of the mixture occurs. This temperature, we find is'about 300 F. When all the water has been driven oif, the mixture is filtered in the manner and by means well known and used in the art, and thereby those compounds which in the oils are naturally contained and act as emulsifiers are eliminated completely. The proportion which the calci um hydrate sustains to the oil treated is substantially as 1 pound to 1 gallon of oil, and that of the clay to the oil substantially as 1 pound to 1 gallon of oil. -When these ingredients are admixed with the oil, the resulting I mixture is agitated for a period of time suffi cient to bring about the reaction or adsorption of the calcium hydrate upon the soaps or soap forming compounds in the oil. While the time required for this conversion and adsorption of the soap forming ingredi ents to take place is dependent upon various conditions, as the quality of the oil, the quantity of emulsifying agents in the oil, etc., it may be stated that when water no longer is driven off, this is fairly accurate indication that the process-has proceeded long enough to effect the purposes.

We have 'referred to calcium hydrate as one of the alkaline earth metal hydroxides which is capable of converting and adsorbing the sodium soap naturally contained or formed in hydrocarbon oil into compounds which may readily be separated from the oil. There are other hydrates which fall within this class of alkaline earth metal hydroxides and which are capable of effecting the same purposes. Such hydrates are as stated barium, magnesium, etc but it will be under-- stood that any compounds other than the alkaline earth metal hydroxides mentioned herein, which are capable of bringing about the reaction on the sodiumsoap compounds in the manner described are included within the spirit of this disclosure. vNor is this disclosure limited in the practice to the preliminary treatment with an alkaline solution and then with an agent that will convert the soap forming oil soluble compounds into oil-insoluble compounds. While it is preferable to segregate these practices, and to perform them in accordance with the teaching of this disclosure, it will be understoodthat the treatment of the oil with agents that will convert the soap forming compounds into oil insoluble compounds may occur concurrently with the treatment with the weak alkaline solution, and that the caustic soda treatment may be omitted altogether, because our experience shows that substantially the same results may be obtained by treating the oil directly with an alkaline earth metal hydroxide,

although the results desired are more diflicult to obtain than by the complete process as outlined above. 4

What we claim, is:

1. In the treatment of hydrocarbon oils to free them of emulsifying compounds, the

process which consists in treating the oil with a relatively weak alkaline solution under pressure and agitation with live steam, separating the aqueous solution from they oil;

and in then removing the soap forming compounds by converting them into oil-insoluble compounds, adding clay to the oil thus treat ed and then filtering the oil.

2. The process of treating lubricating oil to remove emulsifying constitutents which consists in mixing with the lubricating oil a relatively weak caustic soda solution, 1n subjecting the mixture to a super-atmospheric pressure, in agitating the mixture with steam; in permitting the mixture to settle,

and in removing the aqueous portion'of the 4 mixture; and in then removing the soapforming compounds by converting them into separable adsorptive compounds, involving mixing with the oil thus treated an alkaline treated oil with an alkaline earth metal com-= pound and an adsorbent clay at a temperature of approximately 300 F. and finally separating the purified oil from the alkaline earth metal compound, and absorbent clay contain ing the emulsifying constituents.

4. The process of removing emulsifying constituents from lubricating oils comprising commingling the oil with a water solution ofcaustic soda containing not more than three and one-half per centum of caustic soda and in quantities sufficient to neutralize and combine with all the emulsifying con stituents'contained in the lubricating oil, agitating-the mixture of lubricating oil and caustic soda solution with steam under pressure greater than atmospheric, separating the aqueous solution from the oil, then commingling the separated oil with a mixture of calcium hydroxide and an adsorbent clay at a temperature above the boiling point of water, and finally separating the purified oil from the calcium hydroxide and adsorbent clay together with the emulsifying constituents.

5. In the treatment of hydrocarbon oils to free them of emulsifying compounds, the process which consists 'in treating the oil with a relatively weak alkaline solution under pressure and agitation with live steam, separating the aqueous solution from the oil, adding an alkali earth metal hydroxide and an adsorbing agent to remove any remaining emulsifying constituents, agitating and heating the mixture until the water is expelled, and then separating the purified oil from the i hydroxide, adsorbing agent and emulsifying constituents.

In testimony whereof we have set our hands.

JOHN C. BLACK.- WIRT D. RIAL. RAYMOND T. HOWES.