US1969302A - Treatment of hydrocarbon oils - Google Patents

Description

Patented Aug. 7, 1934 '1 PATENT? OFFICE TREATMENT OF HYDROCARBON OILS Gustav Eglofl and Jacquie C. Morrell, Chicago, 111., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application September 16, 1933,

' Serial No. 689,790 v This invention relates more particularly to the refining of relatively low boiling hydrocarbon distillates at elevated temperatures, especially those resulting from the conversion of relatively high boiling hydrocarbons at elevated temperatures and pressures.

More specifically, the-invention comprises subjecting hydrocarbon oil vapors mixed with steam to treatment with phosphoric acids in the pres ence of solid salts of metals such as, for example,

the salts of aluminum, zinc, tin, copper, lead, iron, mercury, cobalt, nickel, chromium, manganese, molybdenum, vanadium, tungsten, cadmium and others, individual salts being used alone or mixed with others in various combinations which have been found suitable for producing particular treating effects.

The types of salts which are preferred according to the present process are those which have a definite oxidizing action upon hydrocarbon oil vapors under the preferred conditions of treatment in regard to temperature and pressure. As examples of such salts may be mentioned hypochlorites, permanganates, chromates and dichromates. 'Of the salts mentioned as utilizable, each will exert its own particular effect upon the reactions of treatment which is not equivalent to the other salts which may be used alternately, and the selection or any one for accomplishing a particular treating efiect will be determined by matters of expediency and trial in respect to its eiiect upon the reactions.

The acids of phosphorus which are used alternatively though without identically equivalent treating action comprise those in which phosphorus has a valence oi 5, and thus include the following acids, shown along with their formulas, melting points and other properties.

Acid Formula Properties Orthophosphoric" H:PO4(P9O5.3H:O) M. P. 38.6" 0.;%

H2O 213 C. Pyrophosphoric H4PaO1(P2Os.H2O)- M. P. 61 C Metaphosphoric- HP03(P205.H10) Sublimes.

The above acids indicate from their formulas that they represent different degrees of hydra- (Cl. Tilt-36) ly in treating hydrocarbon oil vapors, particularly vapors arising from the cracking of heavy hydrocarbon oils such as those of approximate gasoline boiling range coming from fractionators of cracking plants. The treating eiiect of the acids is controlled and accentuated by the concurrent use of the various oxidizing metal salts mentioned and also by the use of oxygen-containing gases such as' air, oxygen or ozone. The number of metal salts which may be employed in connection with the three phosphoric acids is considerable and various treating effects may be obtained by using difierent combinations of acids and salts along with varying proportions of steam and oxidizing gases. However, each particular combination produces its own treating efiect in the case of any given type of vapors or varying types of vapors so that there is no inference that the many combinations of treating reagents are identical in their treating action.

To obtain the best results with the solid metal= lic salts it is usually preferable to space them by supporting them on or mixing them with-relaaction in any case will depend upon the type of I oil treated and the conditions being employed.

The usual method of refining cracked distill ates is to subject them to treatment with sulfuric acid and alkaline solutions, including plumbite solutions consisting of 'litharge dissolved in alkaline solutionsin various combinations of treatment and subsequently to subject the acid treated product to redistillation usually in the presence of steam. The present invention permits the direct treatment of the hydrocarbon vapors from the cracking process, reducing the cost of reagents and eliminating the redistillation or rerunning operation, although it is within the scope of the invention to revaporize the product in a subsequent operation and subject the vapors to treatment as described.

The invention is more particularly directed to the treatment of vapors of lower boiling cracked distillates though the vapors of straight run distillates may also be treated within the scope of the invention.

In applying the process of the invention to practice any suitable equipment may be employed vapors undergoing treatment with the acids and the solid contact masses may be employed. The contact materials may sometimes be employed in successive strata of varying composition or supported on superimposed trays designed to produce intimate contact.

I It has been found desirable to neutralize the vapors before or after condensation and .to this end the vapors may be treated with ammonia gas or pass counterflow to solutions of alkalis in auxiliary neutralizing equipment or the condensed vapors may be treated with liquid alkalis such as solutions of caustic soda, ammonia, or the like, the traces of reagents and reaction products remaining being washed out with water when found necessary. V

The reactions involved in treatments conducted within the scope of the invention have been observed to produce effects comparable with those produced by sulfuric acid of varying strength used after the customary methods of treatment. The amounts of phosphoric acid rebustion engines.

agent used will vary with the character of the vaporstreated from a fraction of a percent to as high as 5% or higher by weight of the oil vapors treated in cases where relatively heavy treatments are desired. The amounts of oxidizing gases and steam used in conjunction with the acids of phosphorus may also be varied to produce a wide variety of treating effects. The period during which'any particular oxidizing salt will function either chemically or catalytically will also vary, some having relatively long life and being easily regenerated by simple methods and others being effective only for short periods. In some cases by proper proportioning of the oxygen in the gas-vapor mixture undergoing treatment, a balance maybe struck betweenthe loss of oxygen from the salt and its restoration by the oxygen in the mixture so that there is substantially no change in the composition of the solid contact material.

The efiects produced upon oil vapors, particularly those produced from the cracking of heavy hydrocarbon oils by the use of phosphoric acids, oxidizing gases and ,solid contact substances characteristic of the invention are in general those of polymerization or condensation 0L relatively highly unsaturated hydrocarbons or their derivatives, particularly their sulfur derivatives. The net result of the treatment is thus the conversion of gum-forming and sulfur compounds into high boiling polymers or complexes 70' which are .removed by a subsequent fractionat ing step. Such groups of compounds deposit gums under ordinary storage conditions or when fed to the carburetor or-manifold of internal com- Various temperatures of treatment may be asts employed, for example, from 250-600 FR, more or less, and the pressures may be subatmospheric, atmospheric, or superatmospheric. While the results may vary with the conditions employed, the pressures and temperatures are chosen so that the hydrocarbons are treated substantially in the vapor phase. I

As specific examples of the operation of the invention and of the results obtained, a California .cracked distillate of approximately motor fuel boiling range may be vaporized and subjected to treatment with aqueous orthophosphoric acid (see table) of approximately concentration, the vapors being mixed with small amounts of air or oxygen and steam during their passage in a downward direction .through a stationary mass of fullers earth upon which cobalt chromate has been deposited in an amount approximately equal to one-third the weight of the fullers earth. The phosphoric acid may be used in an amount equivalent to approximately 5 pounds per barrel. Steam is used at the rate of approximately 2 pounds per barrel. The untreated product may show a gum content of approximately 450 mgs.

per cc. and have a reddish-brown color, with 100 of approximately 22 mgs. and a colorof 25 on the Saybolt scale. The sulfur content may be found to be as low as 0.1%.

In the case of a mixed Mid-Continent and West Texas cracked distillate treated with approximately the same amounts of reagents, the gum content may be reduced from 275 mgs. to 20 and the color raised from a light amber to approximately 25 on the Saybolt scale. The sulfur content may be reduced from 0.45% to about 0.15%.

The process is particularly suitable to the treatment of cracked distillates produced from California oils. In some cases the untreated distillates may contain 500 mgs. of gum and have a dark reddish color while the treated distillates color of 25 to 30 on the Saybolt scale. The sulfur content may be reduced from 0.48% to 0.12%.

The foregoing description and examples have disclosed a process applicable to the treatment "may have a gum content of only 40 mgs. and a of hydrocarbon oil vapors which has a wide applicability and is capable of great variations in the methods of operation and the amounts of reagents employed. Therefore, the specific cases cited are not to be construed in a limiting sense upon the broad scope of the invention as many other modifications and examples can be given.

We claim as our invention: v 1. A process for refining relatively low boiling hydrocarbon distillates, which comprises subjecting said distillates while in heated vaporous con- 1'35 dition to the action of phosphoric acid in the presence of a solid salt of a metal capable of exerting a mild oxidizing action. I

2. A process for refining relatively low boiling hydrocarbon distillates, which comprises subjecting said distillates while in heated vaporous condition to the action of phosphoric acid in the presence of steam and of a solid salt of a metal capable of exerting a mild oxidizing action.

3. A process for refining relatively low boiling cracked hydrocarbon distillates, which comprises subjecting'said distillates while in heated vaporous' condition to the action of phosphoric acid in the presence of a solid salt of a metal capable of 15 exerting a mild oxidizing action.

presence of steam and of a permanganate of a metal.

6. A process for refining relatively low boiling hydrocarbon distillates, which comprises subjecting said distillates while in heated vaporous condition to the action of phosphoric acid in the presence of steam and of a chromate of a metal.

GUSTAV EGLOFF. JACQUE C. MORRELL.