US2055416A - Method of refining mineral oils - Google Patents

Description

' 'lio Patented Sept. 22, 1936 H 2,055,116 METHOD REFINING OIIiS Franz; Rudolf Moser, Amsterdam, Netherlands, assignor to Shell. Development Company,v San. Francisco, Calif, a corporation ofDeIawai-e' NdDi-"awing Application October 8; 1 934 Serial No. 747,419.: In. the Netherlands. October 1'1;

' 8. Claims. (01; rec-36y This invention relates to a process ofmanufacturing refinedhydrocarbon oil's andis more particularly concerned with atrea'tingjprocess where"- by high grade light fuel oils'are obtained. from hydrocarbon mixtures rich in unsaturated; or aromatic components, such for example as cracked, and especially vapor phase crackeddistiliates. I

It is known that the conventional sulfuric acid treatment, when applied to such dis'tillates,. causes a considerable amount. of'losses, resulting in decreased yields and in" the absence in. the final products of. various compounds, such as. aromatic and unsaturated hydrocarbons, which are highly desirable. therein, since they tend to. impart to the fuel oil high antiknock properties. i

It is therefore. an object of' this invention to provide a process which would" desulfurize, reduce the gum formation and improve the color of the distillates treated in a manner comparing favorably with that of the sulfuric acid treatment, while giving at the same time considerably higher yields and better octanerating's'.

Briefly stated, this process consists in treating thedesired distillate with a small quantity of a monoor poly-sulfonic acid" of an aliphatic and/or. aromatic hydrocarbon, either substituted or not, orwith a mixture of such acids. The hydrocar'bons to be refined are contacted in vapor 30 phase with a solution or suspension of the sulfonic acid in an organic substance inert at the operating. temperature, which makesit possible to carry out the process in the presence of steam.

The sulfonic acids which have been found especially suitable for this purpose are the benzenesulionic acid, the p-naphthalene sulfonic acid, the methane-disulfonic acid, and the sulfonic acids of toluene and xylene. The organic radicles of these acids may be substituted hydrocarbon groups. It was found that. the substituents exert "a definite influence. on the process; thus,.sul-

foni'c acids with a negative substituent, such as a halogen (for example,,parachlorohenzene; sulfonic acid) are usually more suitable than those with a positive substituent such as the amino groups. These sulfonic acids differ somewhat in the action which they exert on thepoil' being. treated. For example, some of them have an especially favorable influence on the color-of the distillate,

while others exert a specific desulf'urizin'g action,

or may increase the anti-knockstability' of the hydrocarbons. By selecting a. certain sulfonic acid',,or by applying. a mixture of such acids, the character of the treating actionmay be controlled in any desired manner. 'Ihe'sulfonic acids must be however,. substantially free of sulfuric acid, since the latter i's easily reduced at the temperatures of the process, and the conversion products thus obtained unfavorably affect the final product.

According to this invention, it is possible to apply the sulfonic acid treatment to petroleum distillates in the. vapor phase and in the presence ofsteam; Such method, while very advantageous' for commercialscale operations, since in the petroleum industry distillation is usually carriedout' with the" aid of steam, wasuntil now: considered'- impracticable, as it" was believed that a continuous supply of steam would completely hydrolize the sulfonic acids and render them ineffective. It has however nowbeen found that substantiallyno such hydrolysis occurs if the sulfonic acids are dissolved or' suspended, in not too great a concentration, in a liquid organic solvent inert at the; working temperature, which is probably'due to the fact that the organic solvent'protects the dissolved sulfonic acid from the action of the steam; The concentration of the acids should preferably be below while the allowable upper limit is approximately 10%. Moreover, it is advantageous towork at a temperature at which there isno substantial hydration, since it has been found that an intensive hydration tends to reduce the solubility of the sulfonic acid in the organic solvent. The temperature consequently has to be. fixed for eachacid separately; although temperatures of about 100 to 250 C. have been generally found very satisfactory.

The desired inert organic solvent may be selected" from pressure distillate residues, lubricating'. oils, gas oils, stove oils, Edeleanu extracts, etc. Since it has been found that it is preferable to use the least. possible amount of the organic solvent capable to protect the sulfonic acid from the hydrolizingfeffect of steam, and since 5111- foni'c acids dissolve more easily in light fractions, it may sometimes be advisable to dissolve these acids, for example, in a relatively light Edeleanu extract, and then to admix the solution in desired proportions with a. heavier oil, such as lu form of a treating column filled with Raschig rings providi'nga large contact surface. known that the light fractions obtained by cracking", the' so-called pressure distillates, usually require. a" redistillation in order to conform to some desired-boiling rangespecifications. In practice, such distillation is generally carried out with the aidof steam, and the mixture of'steam and hydrocarbon'vapors' thus obtained may, before being. passed. to the condensing apparatus, be led through the treating column countercurrent to the. treating agent. The treating agentdissolved" or suspended in an organic inert solvent may be recirculated; and a certain amount of fr'esh'sul- It is fonic acid or the solvent continuously added in order to maintain the desired degree of concentration. It is also possible to use several treating units in series and to pass the hydrocarbon vapors and the treating agent consecutively and countercurrently. through all of them.

. The'treating column should preferably be constructed of a material that does not oxidize easily. Although the metals themselves are not attacked by the sulfonic acids, metal oxides .aredissolved by them so that corrosion takes place, which is affects unfavorably, the treating process. Stainless steel may be advantageously used forthe construction of treating columns, whileenamel 1:

.also be combined'withany of the other known methodsfof treating, which maybe appliedbephenols, mercaptans, 'etc.

fore as well as after the sulfonic' acidtreatment. For example, the oil may be pre-treated with dilute acid, lye, or an absorbent material to remove'certain. constituents such as nitrogen bases, In such cases, it is possible to use a concentration of sulfonic acids evenlower than stated above.

This invention may further be illustrated by jthe followin'g example, without limiting its scope to any of thespecific substances'or steps used.

A vapor phase cracked. gasoline with the'followin'g properties: octane number 69, color'Saybolt, indeterminable, specific gravity 0.753, bromine number 162, gum'300 mg., was distilled with steam, and the vapor mixture, containing about 10% steam, and the vapor were passed consecutively'throughtwo columns filled with Raschig rings, held at a temperature of about 200 C. A

was passed through the secon'd'colum'n counter- 'current, to the vapors, after which the partly spent reagent was mixed with 1% of fresh benfzene-sulfonic acid, and passed through the first column." V a l After condensation, agasoline with the follow- 45 ing properties was obtained: octane number 71, color .Saybolt 2 5, specific gravity 0.752, bromine j number 150, gum 7 mg. The treating losses were very small.

1 j From the above guresitwm be meat that the s50 v tion, is, particularly drawn to they octane numher, which is' even somewhat higher in. the final {product than in. theoriginal gasoline.

process gives, very'satisfactory results. Atten- The relatively small decrease of the bromine number shows thatthe unsaturates had not beenfaffected by the treatment, while the gumrforming components were effectively removed from the 'dis- 65.the invention and subsequentlycondensed, was

, tillatel [It maybe added that ,it'is .sometimes'of advantage to neutralize the acid 'treated distillate with an aqueous solution of sodiuin carbonate instead of sodium hydroxide. 1 This may have a washed in; one case with sodium carbonate',fand

lin theother case with sodi'inn'hydroxide; .The

gum stability of both gasolineswas determined j t lieilfirst case andonlyZO in'the second "perature in contact with an effective quantity of hot liquid organic sulfonic acid substantially free from sulfuric acid and separating the treated vapors from the liquid sulfonic acid. not only detrimental to the apparatus, but also"'-- the refining-of a petroleum distillate in the vaporous state the step of subjecting the vapors at a non-cracking temperature to the action of an effective quantity of hot liquid organicisulfonic acid which is substantially free from sulfuric acid.

3. In the refining of a petroleum distillate in thenvaporous state, the step of subjecting the vaporsat a temperaturebetween 100 C. and

tillate in the vaporous state the step of subjecting the vapors at a non-cracking temperature to the ,act ion of a hot liquid solution of organic sulfonicacid in an organic solvent which is substantially inactive underthe conditions of the treatment, said solution being substantially free from sulfuric acid;

5; In the process of'treating a petroleum distillate in the vaporous state the step of subjecting the vapors at a non-cracking temperature to the actionof a hot liquid solution of organic sulfonic acid,.sa'id solution containingnot more than 10% sulfonic acid in an organic solvent which is substantially inactiveunder the conditions of the treatment and is substantially free from sulfuric acid. 6. In the refining of a'petroleum distillate in the vaporousfstate' the step of subjecting the vapors at a" non-cracking temperature in the presence of steam to the, action of an effective quantityof hot liquid organic sulfonic acid, which is substantially free from sulfuric acid, and under conditions to prevent the condensation of steam.

"7. In the refining'of apetroleum distillate in the vaporous statethe step of subjecting the vapors at anon-cracking temperature of said distillate to'the action of an efiective' quantity of hot liquid organic sulfonic acid, which is substantiallyfree from sulfuric acid, and under,

conditions to prevent the formation of metal sulfonates.' v

8. In the process of treating a hydrocarbon I Idistillateof the type of gasoline in the vaporous state to produce astable gasoline of good color and low gum content the steps of subjecting the vapors ata temperature between" C. and

",tainingnot'more than'l0% of sulfonic acid in an organic solvent which is substantially inactive under the conditions of the treatment, and under conditions to prevent formation of metal sulfohatesseparatirig' the vapors from the treating;v I solution, condensing the treated I vapors, and treating'jthe resulting condensate with an aqueous solution of sodium carbonate, 'whereby a gasoline is produced possessingan octane, number which is higherv than that :of the original distillate. V