US1940861A - Process for refining sour hydrocarbon oil - Google Patents

Description

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Patented Dec.,26, 1933 I 5:;

PROCESS REFINING soUR-nYDitooAm Lawrence M. Henderson, Narberth, 1a., assignor I V to The Atlantic RefiningCompany, Philadclv phia, Pas a corporation of Pennsylvania No Drawing.

' Application humid 1931' I S erial:No.507,'l65 I v J I Claims' (o 196'33) l".sou' r oil, that is, anoil which contains merca p' tans, with adoctor solutionwhich comprises an alkaline solution of leadoxlde or litharge, where by lead mer'captides are formed by reaction of the doctor solution withmercaptans contained in the (oil. Although lead mercaptides of low molece ular weight, for example, ethyl mercaptide; are

insoluble in oil and precipitate upon formation, the lead mercaptides of higher molecular weight are oil soluble and therefore remain in, solution .in the oil after the doctor solution is separated from the oil. For this reason, itis customary in the art to add elementary sulfur to the oil, thereby forming organic disulfides and insolublelead sulfide by reaction of the sulfur with the lead mercaptides. In practice the elementary sulfur is customarily added to the oil prior to or simultaneously with the addition of the doctor solution, although it is possible to withhold addition of the sulfur'until the spent doctor solution has been separated. from the oil.

The addition of elementary sulfur to litharged oil-for the purpose of'breaking the oil, that is, for precipitating lead 5 hide is objectionable in that an unavoidable excess of sulfur. is customarily employed. This excess sulfur remains in solution in the oil, thereby increasing the total sulfur content thereof, and causing the oil to react to the corrosion test.

A primary object of thepresent invention is to provide a process for breaking so that the objections incident to breaking such an oil with elementary sulfur are avoided.

I have found that litharged oil may be broken, withthe consequent formation of an insoluble lead-containing precipitate, by treating the litharged oil after separationof the doctorsolution therefrom with an aqueous solution of cupric chloride. L

In accordance with my invention a sour oil,

for instance, a sour gasolfne or lamp oil, is treated sodium plumbite or doctor somanner. For example, be added to the oil and with a solution of lution in any well known the doctor solution may the mixture agitated toinsure proper contact. After proper reaction the mixture may be settled and the spent doctor solution which forms a lowlithargecl 1 oils water erlayer may be separatedby draining. As cupric chloride'jis an acid salt it is preferred towash 7 the litharged oil withwater subsequent tothe separation of the spent doctor solution.' Otherwise small amountsof cupricchloride will be lost .60

to the residual alkali of the lithargedjoil. The

water wash, however,' does not. remove from the oilthe lead mercaptides"which?were formed by "treatmentwith the doctor sol ion- .710' the l t a s d o l s h n'add anemia 5 solutionof cupric chloride, andthe resultant 'ture is thoroughly agitated to provide proper contact between the cup ric chloride and the lead mer:

.capltides'contained in the oil. There results the precipitate whichisfoiind 7 0 to contain lead chloride. Upon completion of the reaction'the mixture is allowed to stand, with the formation of. a two-layer system. The lower layer-of this system comprises thespent cupric I formation of a White chloride solution in admixture with the precipitate of lead chloride, while the upper layerconsists of the oil'which is now sweet and free from lead and copper compounds. These layers may be separated, for example-by decanting the oil.

It is preferred that the-cupric chloride solution contain at least 10% cupric chloride at-the beginning of a run, and it is possible to employ a saturated solution of cupric chloride to advantage. Ordinarily, a cupric chloride solution of about 26% concentration is preferred.

The amount of cupric chloride solution necessary tocompletely break the oil and render it sweet will depend upon such factors as the amount of lead mercaptides present in the oil and the I concentration of the cupric chloride solution; Ito'o is to be pointed out that an advantage of myfprocess over the customary procedure of breaking litharged oils with elementary sulfur is that the addition of an excess of my cupric chloride solu- 7 tion over the amount necessary to break the oil -95. isharmless, and in fact expedites' the reaction.

A further advantageof my process is that it may be carried out semi-continuously or 'continuously, in a manner which one skilled in the art will immediately recognize.

erence to the following example of its operation.

A quantity of gasoline obtained by thermal decompositionof a gas oil from a West Texas crude oil was washed with a caustic solution to remove hydrogen sulfide, and then treated with an aqueous solution of sodium plumbite. After separa tion of the plumbite solution the gasoline was washed. To 250 parts by volume of this gasoline was added25 parts by volume of a 20% found to be sweet to the doctor test and free from lead compounds. The same cupric chloride solution was used to break 10 additional batches of the litharged oil, each batch comprising 250 parts by volume of oil. Thereafter the copper chloride solution failed to break further quantities of the litharged oil, indicating that the solution was exhausted.

Whereas, the above description is specific to cupric chloride, other cupric compounds coming within the scope of my invention, namely other cupric halides or salt mixtures, such as a mixture of cupric sulfate and sodium chloride, which on being put into solutionionize to provide copper and. halide ions, are intended to be covered in the appended claims asequivalents, and the term cupric chloride as used in said claims is to be understood to include such equivalents.

. What I claim is:-

7 I. A processfor refining a sour hydrocarbon oil, which comprises treating said oil with a solution of sodium plumbite, whereby oil soluble lead compounds are formed separating the oil from said treating solution, treating the separated oil with an aqueous solution of cupric chloride, thereby to form lead compounds which are insoluble in oil, and separating the oil from said aqueous solution and from insoluble substances resulting from the treatment with said aqueous solution.

2. In the process of refining a sour hydrocarbon oil, which comprises treating said oil with a solution of sodium plumbite, whereby oil soluble lead compounds are formed, and separating said treating solution from the oil, the step of precipitatinginsoluble compounds of lead from said oil by treatment with an aqueous solution of cupric chloride.

3. A processfor refining a sour hydrocarbon oil, which comprises treating said oil with a solution 7 of sodium plumbite, whereby oil soluble lead compounds are formed separating the oil from said treating solution, treating the separated oil with an aqueous solution of copper chloride containing at least substantially 10% cupric chloride, thereby toiform lead compounds which are insoluble in cupric chloride, thereby to form lead compounds which are insoluble in oil, and separating the'oil 1()5 from said aqueous solution and from insoluble substances resulting from the treatment withsaid aqueous solution. LAWRENCE M. HENDERSON.)