US2394978A - Refining process - Google Patents

Description

lytically cracked petroleum alkylated merated herein are purely illustrative and impose any limitation thereon.

' Passes rat. s, me

ammo rnocnss Richard 0. Brandon, Elizabeth, N. L, assignor to Standard Oil ration of Delaware Development Company, a corpo- No Drawing. Original application April 2, 1942. 7

Serial No.

7 437,364. tion December Divided 12, 1942, Serial No.

and this applica- '7 Claims. (Cl. 260-627) division of my co- 43'7,364, flied April The .present application is a pending application Serial No. 2, 1942. v 1

The present invention relates to improvements in the refining of hydrocarbon oils and, more particularly, it relates to an improved method for inhibiting petroleum distillates, such as gasoline, to produce a refined product which is stable against gum Iormation.

It is generally known that gasoline and other hydrocarbon distillates, particularly it they result from a cracking operation, contain substantial quantities of materials which, upon storage, rorm gums. In certain cases, the rormation of gum is so great that the gasoline or other distillate must be redistilled; that is tosay, when a hydrocarbon oil such as gasoline is treated under certain re-- fining conditions and shipped to some distant bulk station where it remains in storage for weeks or even months, there is imminent danger that during storage the rormation of gummy. constituents in the gasoline and other distillate will take place. Obviously the presence constituents in a gasoline is highly undesirable, tor their presence in the carburetor of an automobile seriously'interieres with the efiicient operation thereor.

Prior to my invention, others have proposed the addition of so-called guminhibitors to gasoline in order to prevent the i'ormation or the aforementioned gummy constituents. Among the common inhibitors that have been proposed are the tricresols (meta, para and ortho cresols) and other phenols. While these products are satisfactory gum inhibitors, relatively large quanti- ,ti es are required, and like many of the other commercial gum inhibitors they are also relatively expensive.

.It is the main purpose of my present invention to providemeans for producing a gum inhibitor which is satisfactory from the standpoint oi eirectiveness and whose use aflords substantial economies,

Briefly, m present process involves treating a gasoline to prevent gum rormation with cataphenols. Other objects my invention will appear from the iollowing more detailed description and claims.

In order to illustrate my inventionmore fully, the following speciiic example .is set forth with the understanding. that the precise details enudo not or these gum Y presence precipitation of the .fled precipitate was system. The system consisted or an upper oil layer, an intermediate sodium phenolate layer, and a lower caustic soda solution layer. The

several layers were separated by decantation,

whereupon the intermediate phenolate layer was treated with CO2 although other acidic material could have been used in order to. convert the phenolates into-the corresponding phenols.v The exact amount or acidic material necessary to effect the desired conversion will of course depend on the quantity of phenolate present. However, care must be taken in precipitating the phenols, since the caustic soda extract also contains naphthenic acids so that rial must be employed which will cause the aforementioned Iractional precipitation or selective desired phenols. The acidifreed of asphaltic material by vacuum distillation during which 10% or the material was taken overhead as a product, the

bottoms being discarded. The distillate thus obtained contained alkylated phenols.

The distillate obtained as herelnbeiore explained was then catalytically cracked in the of a cracking catalyst consisting of acid treated Montmorillonite clay. However, a synthetic gel catalyst,v say one consisting of silica and alumina gels could have been used, During the cracking operation, the distillate was vaporized and then heated to a temperature or 880 E, whereupon it was contacted reaction products were then condensed and fractionated and a traction boiling -'ml. oi. gasoline, the 46 minutes.

within. the range oi! from about 120-402? F. at 25 mm. pressure was recovered. The yield of this product was approximately on feed.

When 10 mg. of this material was added to .It should be exp ained that the breakdown" time is a commonly used method for determinin: in the laboratory the eflectiveness or an addition agent as a gum inhibitor. "I'he'determination is made by introducing 25 cc. of the gasoline into a test tube which is then inserted into a bomb. The bomb is placed under 100 lbs. oxygen pressure at room temperature and then heated to a temperature or 212'1'; The time eiapsed betorethereisaalbadropinpressui'oas an acidic matewith the aforesaid "breakdown time" was 270 'tion in known manner.

from the maximum pressure attained in the bomb is recorded as the breakdown period. a

It should be noted that in the text hereinbefore mentioned, the base gasoline (the gasoline containing no inhibitor) had a'breakdown itself oi 100minutes and therefore the inclusion of mg. of the catalytically cracked phenols increased the resistance to gum formation by an amount equal to 170%.

In order to show the utility of my present invention, I submit the following data. In making, the below comparative tests, tricresol was used on the one hand and the product of Example 1 on the other hand, in the manner indicated in the said table:

. Cracked Trlcresol alkylated phenols Amountadded "milligrams-. 10 20 1o Breakdown time .minutes. 170 290 270 It will be noted from the above data in which a standard commercial gasoline was treated with both the tricresol and the cracked alkylated phenols that the cracked alkylated phenols were approximately twice as effective as the commercial tricresol inhibitor.

Also, it should be pointed out that the phenols before cracking had a sulfur content of 0.6%, while after cracking this quantity was reduced to 0.28% which means of course that the cracked ..phenols introduced less sulfur into the treated ,gasoline. With respect to color, it is pointed out that the alkylated phenols before cracking had a color of 1 Robinson, whereas after cracking the phenols had a color of 18 Robinson.

In a further test where 20 mg. of the uncracked alkylated phenols were added to another portion of the above mentioned standard commercial gasoline, the breakdown time was 310 minutes.

see ers I To recapitulate, my invention resides'in'the I concept of catalytically cracking alkylated phenols of petroleum origin and employing the reaction products as addition agent to hydrocarbon oils such as gasoline, where they serve as inhibitors. Since these products have a very high degree of effectiveness, smaller quantities may be used, and therefore their use affords a substantial economy.

Many modifications of my invention falling within the spirit thereof will readily suggest themselves to those familiar with this art, and it is my intention to claim all of the subject matter herein disclosed and all modifications which are included by necessary implication except that subject matter excluded by the terms of the appended claims.

What I claim is: i

l. The method of preparing cracked phenols which comprises subjecting a petroleum fraction to the action of caustic soda, separating an extract phase containing alkvlated phenols, treating said extract with a precipitant for phenols selected from the group consisting of carbon dioxide and mineral acids so as to precipitate the phenols while leaving naphthenates in solution and subjecting the precipitated phenols to catalytic' cracking at a temperature of the order of 800 to 1,000 E, a pressure not substantially above atmospheric and a flow rate of the order of 0.2 to 2.0 volumes of phenol per volume of reaction zone per hour, in the presence of an acid treated clay catalyst.

2. The method of claim- 1 wher leum fraction is a gas oil. 3. The method of producing gum inhibitors for stabilizing gasoline which comprises subjecting alkylated phenols derived and separated from petroleum oil to catalytic cracking at a temperaein said petro- 40 ture of the order of 800 to 1,000 R, a pressure It is obvious from the above data therefore that cracking zone at a flow rate of from 0.2-2.0 volumes of phenol per volume of reaction zone per hour, and the pressures may vary from subat mospheric pressure to atmospheric pressure, or thereabouts.

Instead of .using C02, 1 may use a strongly acidic material such as the mineral acids, but

the quantity added must be carefully controlled to precipitate only phenols and leave naphthemates and other undesired constituents in solu-v not substantially aboveatmospheric and a flow rate of the order of 0.2 to 2.0 volumes of phenol per volume of reaction zone per hour. i. The method specifled' in claim 3 wherein the catalyst employed for cracking is an acid treated clay.

5. The method of producing compounds effec tive to prevent gum formation which comprises subjecting alkylated phenols derived and separated from petroleum hydrocarbons to cracking in the presence of an acid treated clay catalyst.

6. In the'method of producing gum inhibitors for gasoline by extracting alkylatedphenols from petroleum oil with caustic alkali and precipitating the alkylated phenols with an acid precipitant the improvement which comprises subiecting the precipitated alkylated phenols to catalytic'cracking at a temperature of the order of 800 to 1,000 F., a pressure not substantially above atmospheric and a flow rate of the order of 0.2 to 2.0 volumes of phenol per volume ofreaction zone per hour. I

7. The method set forth in claim 6 wherein'an acid treated clay is used as the catalyst.

RICHARD C. BRANDON.