US723368A - Process of purifying and desulfurizing crude petroleum and petroleum distillates. - Google Patents

Description

5 cause complete oxidation.

50 ating the oil.

UNITED STATES.

"PATENT.- OFFICE.

THEODORE F. COLIN, on ELIZABETH, NEW JERSEY, AND OTTO P. AMEND, on NEW YORK, N. Y.

PROCESS OF PURIFYING AND DESULFURIZING CRUDE PETROLEUM AN D' PETROLEUM DISTILLATES.

SPECIFICATION forming part of Letters Patent No. 723,368, dated March 24, 1903. Application filed February 15, 1902. Serial No. 94,326. (M Specimens-l To all whom it may concern.-

Be it known thatwe, THEODORE F. COLIN, residing in the city of Elizabeth, county of Union, and State of New Jersey, and OTTO P.

5 AMEND, residingin the city, county, and State of New York, citizens of the United States, have jointly invented a certain new and useful Process of Purifying and Desulfurizing Crude Petroleum and Petroleum Distillates,

' of which the following is a specification.

The object of our invention is to remove the sulfur from crude petroleum and its distillates by the use of active agents which are more efiective when employed as described and to do it more cheaply than has heretofore been achieved by other processes.

We have observed that thesulfur contained in crude petroleum can be readily removed by washing with an alkali or with sulfuric .0 acid after it has been oxidized and that the extent of its removal depends upon the completeness of its oxidation.

Our invention is based upon the discovery that the oxidation'of the sulfur contained in crude petroleum or its distillates ismore use of an oxygen-carrier or catalytic agent,

and good results are obtained if the process.

be practiced at ordinary or slightly-elevated temperatures. We have discovered that oxidizing action here is more important than precipitation and that those agents which,

like sodium plumbate, precipitate the less-refractory sulfur from the hydrocarbon compounds, but have too weak an oxidizing action on them, are insufficient for our purpose.

Thus although sodium plumbate has been used as an oxidizing agent and gives a pre cipitate of the sulfur in the form of an insoluble sulfid it has only-a weak oxidizing action, and the object of our invention is to We therefore use strong oxidizing agents which do not cause precipitation. We have found that chlorin is the most satisfactory oxidizing agent; but the sulfur must be removed without chlorin- Of course chlorin produces a hypochlorite in an alkaline solution, and

without other oxidizing agents for purifying Oils which are not intended for high-grade illuminating-oils; but such solutions of the hypochlorites will in their use liberate some free chlorin, which enters into'combination, with the hydrocarbons of the oil, especially those of an unsaturated character, such as the olefines, and the chlorin is not readily removed thereafter. The presence of chlorin, however, in a good illuminating-oil is detrimental, especially if much more chlorin were put in than sulfur taken out.

In order to insure the production of oxygen alone without'free chlorin, we employ as a catalytic agent which acts as an oxygen-carrier preferably a salt of a metal which forms two or more oxids, which by oxidation or reduction, respectively, easily pass from one state ofoxidation to a higher or lower state. Suitable salts for this purpose of producing a very pure oxygen from, the hypochlorite solution are the nitrates of manganese, cobalt, nickel, copper, and iron. It is necessary also besides this catalytic agent to have the solution distinctly alkaline in order to prevent the formation of free chlorin, and though this can be assured by the addition of a caustic alkali to the solution it is generally unnecessary to make such addition, as the solution of the hypochlorites of the alkaline metals or alkaline earthy metals practically always contain an excess of alkali, and if our preferred process be practiced the oil will be alkaline through its previous treatment with soda. The third important condition is the introduction of the chlorin in such a way that there shall be at no time any excess of chlorin presentt'. e., the hypochlorite solution must be allowed to run into the oil very slowly and gradually (during the whole time necessary for agitation) and only as fast as the catalytic agent can react upon it. In orderto insure this result, we preferably first treat the Oil, before subjecting it to the subsequent steps of our process, with a strong solution of canstic soda, the solution having a specific gravtion of sodium or calcium hypochlorite,

(bleaching-powder,) to which has been added a very small quantity of manganous nitrate, as hereinafter described. This manganous salt by interaction with the alkali and hypochlorite present is converted into manganese dioxid, which gives'up its oxygen to the sulfur compounds of the hydrocarbons, itself being reduced and then again reoxidized by the hypochlorite, and so on. The direct addition of manganese dioxid (MnO to the oil a mixture might'be used; but it will not be as effective, because the manganese dioxid,-When introduced into the mixture, as described,will exist in a much finer state of subdivison, as powdered manganese dioxid is not as finely divided as the precipitate produced in the solution by neutralization and agitation. The agitation is done by means of compressed air. This helps the oxidation and also carries away any free chlorin that may be present; but under these conditions no appearance of any free chlorin can be detected either by the sense of smell or by visible fumes with ammonia. The reaction above described takes place more easily at a somewhat elevated temperature, and therefore in cold weather the oil ought to be warmed. A temperature of about 40 centigrade is favorable; but satisfactory results are obtained at a temperature of about 15 to 20 centigrade. When the nitro-prussid test shows that all the 'sulfur has been oxidized, we stop the agitation, let 1 the fiuid settle, and draw off the lower alkaline liquid. Nitro-prussid of sodium gives a red color with sulfids in alkaline solution; but when on application of a drop of an aqueous solution of nitro-prussid of sodium to a drop of petroleum previously made alkaline.

with a drop of sodium ethylate dissolved in alcohol there is no appearance of any red color. It indicates that the oxidation of the sulfur in the petroleum has been completed.

The quantity of the hypochlorite to be used depends upon the amount of oxidizable sulfur present in the oil. We have found that if the oil contains, for instance, 0.3 per cent. of sulfur, it requires about 0.2 per cent. of chlorin for its oxidation, and if the amount of sulfur in the oil and the amount of available chlorin in the hypochlorite solution are known the proper quantity of the hypochlorite can be easily determined; but it maybe pointed out that a slight excess of the hypochlorite will cause no harm, (it will even save time,) for the excess of the chlorin will l I be subsequently neutralized, as described be low.

Some hypochlorous acid (or its salt) will remain suspended or dissolved in the oil, and this must be removed or destroyed. We effect this by treating the oil with a reducing agent, which in contact with the hypochlorous acid or its salt will abstract the oxygen from it. To accomplish this double purpose of forming an indifierent or inactive chlorid and of freeing the distillate of the chlorin, we add to the still slightly alkaline oil a solution of a salt of a metal which has two or morestates of oxidation, each of which easily passes into the other, so that it can act as a reducing agent. Suitable salts for this purpose are ferrous sulfate, (copperas,) manganous sulfate, ferrous and maganous nitrates, ferrous and maganous chlorids, ferrous and maga nous acetates, or sodium plumbate. As fer' cheap, We prefer to use this salt. A solution of copperas (or some one of the other salts mentioned above) added to the oil containing chlorin and agitated with itfor a little time will interact with the chlorin, so as to form ferric chlorid, which is harmless in the mixture.

With the hypochlorous acid present the reaction can be represented thus:

This equation also shows the necessity of a certain definite minimum quantity of the iron salt to bind or neutralize all the chlorin present. Of course manganous nitrate could be used at this stage also, asit has been used in the previous one; but as the iron salts are cheaper we prefer to use them, since a muchlarger quantity of the agent is required here.

If the methods above described have been followed carefully, the oil or distillate isnow rendered free from refractory compounds. The total sulfur has been reduced to about one-half the original quantity, and what remains is in a form which submits to the usual acid treatment of petroleum distillates. A little doctor t'. e.-,sodium-plumbate solu tionwill show that all hypochlorous acid has been decomposed. As long as any of this latter is present sodium plumbate will turn black from the formation of lead peroxid. After letting the oil stand for a little while to settle, drawing off the aqueous liquid, and washing the distillate a couple of times with water, the oil is now ready for the usual treatment with sulfuric acid, alkali, and wannnecessary to describe.

We may give the following as a specific exstood as illustrative only and not exclusive. We took two hundred and fifty cubic centimeters of a mixed petroleum distillate which conrous sulfate (copperas) is very efiective and ter in the Well-known manner, which it is ICC ample of our process, and it is to be undertained, in about equal volumes, the saturated hydrocarbons which produce the water-white kerosene of commerce and the unsaturated hydrocarbons (mainly olefines) produced by the cracking process of distillation, which gives only an inferior burning-oil. The weight of the oil was about two hundred grams.

First. We washed this distillate with about five cubic centimeters of a strongsolution of caustic soda in order to neutralize acids, phenols, 850., and separated the resulting alkaline sludge.

Second. We next added to the oil gradually, drop by drop, fifty cubic centimeters of a solution of sodium hypochlorite. This solution was strongly alkaline (and therefore needed no addition of caustic soda) and contained 0.48 grams of available chlorin in one hundred cubic centimeters of the solution, or a total of 0.24 grams chlorin to two hundred grams oil 0.12 per cent. chlorin. To this we added one drop of a weak solution of manganous nitrate, as a catalytic agent, and agitated the liquid by means of an air-blast for one hour while the hypochlorite was dropping in. At the end of that time the sodium nitroprussid test showed the absence of sulfids in the hydrocarbons; The temperature of the room was about 17 centigrade.

Third. After allowing the liquid to settle and drawing off the alkaline solution we washed the oil four times with water- Fourth. Assuming as a very improbable maxim that one-eighth part of the chlorin previously added still remained in the oil, we now added twenty cubic centimeters of a copperas solution containing 0.2 grams of solid ferrous sulfate and agitated the liquid with an air-blast for twenty minutes. At the end of that time a test of a small portion of the solution with sodium plumbate showed that the plumbate did not turn black by the formation of PbO thus proving the absence of hypochlorous acid. We allowed the liquid.

' washing with Water and alkali.

The result was an oil of good color, standing the usual test with sodium plumbate, free from manganese and iron, and containing (as shown by the combustion test) a mere trace of chlorin and sulfur in quantity sufilciently low for commercial purposes.

The process described above may be practiced, as stated, by the use of the difierent agents described and will answer for the reduction of sulfur in crude oils and their distillates.

Having thus described our invention, what we claim is l. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein (without precipitation of the sulfur) by means of a hypochlorite in alkaline solution in the presence of an oxygen-carrier or catalytic agent, at ordinary or slightly-elevated temperatures, substantially as described.

2. The process of desulfurizing petroleum and its distillates which consists in theoxidation of the sulfur contained therein by means of a hypochlorite in alkaline solution at ordinary or slightly-elevated temperatures in the presence of an oxygen-carrier or catalytic agent, and the subsequent removal of the excess of chlorin by means of a ferrous salts, substantially'as described.

3. The process of desulfurizing petroleum and its distillates which consists in the oxidation ofthe sulfur contained therein by means of a hypochlorite in alkaline solution at ordinary or slightly-elevated temperatures, and the subsequent removal of the excess of chloin by means of a solution of a metallic salt having two or more states of oxidation readliy transformable one into the other, sbustantially as described.

4:. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein by means of a hypochlorite in alkaline solution in the presence of an oxygencarrier or catalytic agent, at ordinary or slightly-elevated temperatures, and the subsequent removal of the excess of chlorin by means of a solution of a metallic salt having two or more states of oxidation readily transformable one into the other, substantially as described.

5. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein by means of a hypochlorite in alkaline solution in the presence of an oxygen-carrier or catalytic agent, at ordinary or slightly-elevated temperatures, and the subsequent removal of the excess of chlorin by agitating with a solution of ferrous sulfate, substantially as described.

6. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein by means of a hypochlorite in alkaline solution in the presence of manganous nitrate, at ordinary or slightly-elevated temperatures, substantially as described.

7. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein by means of an oxidizing agent in alkaline solution in the presence of manganous nitrate, at ordinary or slightly-elevated temperatures, and the subsequent removal of the excess of chlorin by means of a solution of a metallic salt having two or more states of oxidation readily transferable one into the other, substantially as described.

8. The process of desulfurizing petroleum and its distillates which consists in the oxidation of the sulfur contained therein by means of a hypochlorite in alkaline solution in thepresence of manganous nitrate,at ordinary or slightly-elevated temperatures, and the subsequent removal of the excess of chlorin by IIS ' 723,368 4 A tsiutheoxidand its dlstillates which consls means of ferrous sulfate, substantlally as de aim} of the sulfur contamedfligremigtggagi IS scribed. of desulfurizing petroleum I ofan oxidizing," fientellgvadltlzaiipeergpemmrks, I n 3 il s islt i ll i e s which consists in the oxidaordgxzgiysggszligentylemoval of the excess of b means an bstan- 5 non of d' i dfr ;g:: 2:1 :31 a ll l il ie golution chlorin by meagsgf ferrous sulfate, su

9f l h e r 'er ange o f an oxygen-carrier or catatially as descri e I HEODORE F. COLIN. lg rtic agent, at ordinary or slighsly-eleggteg OTTO P. AMEND.

0 t eratures and the subsequen rem 1o thg xccss of hhlorin b3 mealpsdof ferrous sul b tantially as escri e l%. "l h: process of desulfurizing petroleum Witnesses:

W. HARRES, J AOOB B. TooH.

I It is hereby certified that in Letters Patent N 0. 723,368, granted March 24:, 1903, upon the application of Theodore F. Colin, of Elizabeth, Nev; Jersey, and Otto P. Amend, of New York, N. Y., for an improvement in Processes of Purifying and Desulfurizing Crude Petroleum and Petroleum Distillates, errors appear in the printed specification requiring correction, as follows: On page 1, line 56, the word effect should read aflect: page 2, line 52, a comma should be substituted for the period after the Word color, and the following word It should commence with a small 1 instead of a capital; same page, lines 84, 85 and 85-86, the word maganous should read manganous; page 3, line 35, the word maxim should read maximum; same page, line 78, the Word salts should read salt; and in lines 87 and 88 the Words readily and Signed and sealed this 14th day of April, A. 1)., 1903.

[SEAL] F. I. ALLEN,

, Commissioner of Patents.

Corrections in Letters Patent No. 723,368.