US2194321A - Treatment of hydrocarbons - Google Patents

Description

Patented Mar. 19; 1940 I i TREATMENT or I mnoollnnons Donald L. Pennington and Wayne L. Benedict,

Chicago, Ill., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware -No Drawing. Application December 31,1937,

Serial No. 182,920

12 Claims. (01. 196-30) This invention relates particularly to the treatposed and some have attained commercial imment of the lower boiling naphthas and gasolines portance. The use of hypochlorites has been produced in the straight run distillation and in found applicable to certain distillates, princithe cracking of petroleum though it may also be pally those of a straight run character and a applied to analogous low boilingdistillates prolater development has involved the use of cop- 6 V duced in the primary distillation of any natuper compounds and it is with improvements in rally occurring hydrocarbonaceous materials or this last named type of sweetening process that in the secondary distillation of their primary the present invention is concerned.

tars. y In one specific embodiment the present inven- 1 More specifically the invention is concerned tion comprises the treatment of copper-sweetened 10 with improved methods'for treating crude prihydrocarbon oils for the removal of color and mary gasoline boiling range distillates to render undesirable dissolved constituents therefrom by them sufflciently stable and pleasing in appearpercolating said hydrocarbon oils through beds ance and odor from a sales standpoint. r of granular solid contact materials comprising as Primary naphthas and gasolines'quite uniformtheir active constituent the salts of ortho P1108.- 1 ly require some type of chemical treatment to Phor e a d h as fo exa p ammonium P eliminate objectionable constituents of a colored, phates and the various phosphates of the alkali odorous or gummy character. The question of and alkaline earth metals. the cause of color is still in dispute although it Owing to the relatively small percentages of has been variously attributed to suspended ascompounds inv lv in the sweetening reactions. 90 phaltic and resinous materials, oxidized hydrot e course of Copper-sweetening from the carbons, nitrogen compounds and even to some ical standpoint is not entirely certain. In such pure hydrocarbons. The objectionable odors ar sweetening pro large number of ppe principally due to sulfur compounds of which t e compounds may be employed either in a dry state chief offenders are the sulfur alcohols or merca or in solution and while in some cases there'may 2 tans. The gummy or potential gum-forming co be actual removal of sulfur by combination with stituents are probably heavy hydrocarbon pol pp r. h r m y i Other cases be m lfely the mers or highly unsaturated hydrocarbons such formation of copper mercaptides or atrue oxidizas conjugated diolefins respectively. ing action depending upon the character of the It is the object of all chemical treatments to pper salt employed. It is therefore not possible 30 remove suflicient quantities of thegroups of imto state exactly what reaction products are press purities mentioned above until they are reduced ent in a copper-sweetened gasoline such as, for to a point corresponding to a finished gasoline. example, a cracked gasoline. to cause an incre se The application of so-called "sweetening agents in'color in the trea e pr b t it h e n may be practiced either before or after the disq i gener lly erved that hisv in re in 35 tillation following acid treatment or may be apc0101 eeeurs- There are some indications t a plied to distillates which have not, received any it may be d e to pp p i es n a acid treatment. These sweetening reagents may be due in part to oxidized compounds dc- 7 apparently transform the foul smelling mercappending upon the copper compounds employed 40 tans into the relatively odorless and stable dialand the conditions 01 m nt H w v r, it bl disulfides by chemical reactions involving has been found that color of copper-sweetened oxidation with the removal of the mercaptan gasolines is practically always reduced to a minihydrogen and the condensation of the residual mum by th Pr p r use r n l r P ph es radicals, through which the sweetened distillate is perco-.

One of the oldest and best known sweetening lated. treatments involves the use of sodium plumblte Th inv n n prises generally h u e f solutions followed by the addition of minimum ny o t Phosphates 0f the alkali alkaline amounts of sulfur to precipitate lead from the r h metals and m n h u h i is n ininitially formed lead mercaptides and form the te t0 infer t all of the compounds W h desired organic disulfides. owing to the numer-' may us d a t rnat w ll hav a t y th ous operating difliculties attending the use ofsame effects in the secondary treatmentof copplumbite such as the tendency to emulsion for- 1 per w et n gesolines- A8 a l the d PM mation and the danger of having t use too much phates give the best results and of those included sulfur to "break" the lead from solution, numer- 1n e group-mentioned, the um- 6 ous other sweetening treatments have been prodl y oien ortho Ph p acid flpp rs o be one of the best reagents. Owing to the uncertain character of the contaminating materials present in the distillates sweetened by copper, it is not possible to state exactly what chemical or phy ical reactions may be involved in the use of the granular phosphates as secondary reagents, and no attempt will be made to offer an exact explanation of the action. There may be some transposition of bases or some direct chemical action of the phosphates on the colored materials, but such possible reactions have not been checked by analytical work and reliance is merely placed on the observed results. Since sour stocks to be treated by the copper method will vary widely in composition, particularly in regard to the mercaptan content both in regard to quantity and to quality, it is obvious that the products of the sweetening reactions will vary correspondingly and that difierent phosphates in the groups mentioned may have entirely different effectiveness when dealing with different charging stocks.

In applying the process of the invention the phosphates are preferably employed in finely divided condition mixed with spacing agents of a relatively inert character such as crushed silica, crushed firebrick, fullers earth, etc. ,Secondary treatments are brought, about by merely passing the copper sweetened distillates through the granular secondary reagents which are preferably contained in vertical cylindrical treating towers or columns through which the distillates are passed downwardly at ordinary temperatures. While, as a general rule, the phosphate reagents will treat a sufilcientlylarge amount of copper 35 sweetened distillate to permit discarding it at the end of its period of usefulness, the invention may further comprise the use of any necessary reactivation or recovery steps to regenerate the phosphates for reuse.

The following example is given to illustrate results obtainable in the use of the compounds char-, acteristic of the invention in effecting further purification of copper sweetened distillates. While the data are entirely representative, it is not intended that they shall impose undue limitations upon the inventions proper scope.

A cracked gasoline produced from stocks from the Mid-Continent-West Texas area was first sweetened by passage through a composite material containing crystalline copper sulfate, ammonium chloride, crushed firebrick, and some water. It was then passed through a mixture of equal parts by weight of finely divided granular monoammonium dihydrogn ortho phosphate and pumice and the following tabulation of data includes some of the significant properties of the gasoline (1) before any treatment, (2) after the copper sweetening, and (3) after the final treatment in accordance with the invention.

From the above data it can be seen that the eries.

use of the ammonium phosphates as a secondary treating reagent improved the color considerably over the color of the gasoline after the copper sweetening, also that it improved the induction period somewhat when no inhibitor was employed, and still more when a small amount of inhibitor was employed as is customary in most oil refin- It is to be noted that the inhibitor susceptibility is considerably better in the case of the sample subjected to the final treatment with ammonium phosphate, there being an increase in induction period of 140 minutes when the inhibitor was added to the sweetened material before the final treatment and an increase of 185 minutes when the same amount of inhibitor was added after the final treatment.

The nature of the present invention and its practical possibilities are evident from the foregoing description and numerical data, neither of which is intended to unduly limit its proper scope.

- We claim as our invention:

1. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweentening action of a copper compound and thereafter treating the distillate with an ammonium salt of ortho phosphoric acid to remove objectionable reaction products of the copper sweetening.

3. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate'to the sweetening action of a copper compound and thereafter treating the distillate with an alkali metal salt of ortho phosphoric acid to remove objectionable reaction products of the copper sweetening.

4. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter treating the distillate with an alkaline earth metal salt of ortho phosphoricacid to remove objectionable reaction products of the copper sweetening.

5. A method for the refining ofhydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter treating the distillate with an acid salt of ortho phosphoric acid to remove objectionable reaction products of the copper sweetening.

6. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter treating the distillate with mono-ammonium-dihydrogen ortho-phosphate to remove objectionable reaction products of the copper sweetening.

"l. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter contacting the distillate with a solid granular material containing a salt of ortho-phosphoric acid to remove from the distillate objectionable reaction products of the copper sweetening.

8. A method for the refining of hydrocarbo distillates which comprises subjecting. the distillate to the'sweetening action of a copper conipound and thereafter contacting the distillate with a solid granular material containing an ammonium salt of ortho phosphoric acid to remove from the distillate objectionable reaction products of the copper sweetening.

9. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter contacting the distillate with a solid granular material containing an alkali metal salt of ortho phosphoric acid to remove from'the distillate objectionable reaction products of the copper sweetening.

10. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter contacting the distillate with a solid granular material containing an alka- 10 line earth metal salt of ortho phosphoric acid to remove fromthe distillate objectionable reaction products of the copper sweetening.

11. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter contacting the distillate with a solid granular material containing an acid salt of ortho phosphoric acid to remove from the distillate objectionable reaction products of the copper sweetening.

12. A method for the refining of hydrocarbon distillates which comprises subjecting the distillate to the sweetening action of a copper compound and thereafter contacting the distillate with a solid granular material containing monoammonium-dihydrogen ortho-phosphate to remove from the distillate objectionable reaction products of the copper sweetening.

' DONALD L. PENN'INGTON. 4 WAYNE L. BENEDICT.