US1967174A - Treatment of hydrocarbon oils - Google Patents

Description

Patented July .17, 1934 UNITED- STATES PATENT OFFICE- TREATMENT OF HYDROCARBON OILS No Drawing. Application December Serial No. 579,648

,SClaims. (Cl-1M6)- This invention relates to the-treatment of hydrocarbon oils and refers more particularly to the refining oi relatively low boiling hydrocarbon distillates at elevated temperatures, especially those I resulting from the conversion of relatively high boiling hydrocarbons at elevated temperatures. More particularly the invention is directed to- Ward's the removal of sulphur from such hydrocarbons.

More specifically the invention comprises subiectinghydrocarbon oil vapors to treatment with aqueous solutions of oxygenated halogen acids containing salts of metals, treatments being conducted in contact with solid contact materials of a non-metallic nature such as iullers earth, clays, bentonite, bauxite, crushed flrebrick, pumice stone and other materials of an earthy or siliceous nature. oxygenated halogen acids include such acids as hypochlorous acid, chloric acid, bromic 2 acid, iodic acid either alone or in various admixtures and the salts in solution with these acids may be those of such metals as aluminum, zinc, tin, iron, copper, lead, mercury, cobalt. nickel, chromium, manganese, molybdenum and others.

2 The metallic salts are preferably those of other acids than the particular oxyhalogen acid which furnishes the excessacid constituent of the ,treating solution, such salts as chlorides, suliates, phosphates, etc., being used as their solubllities permit. The treating solutions may contain a single salt or combinations of salts. The particu-' lar aggregation of solid contact materials utilized -inanycasewilldependupon the nature oithe vapors treated and the treating effects desired.

85 It is recognized thatmaterials like iuller's earth may have an independent refining effect, quite diiierent, however, from the action oi the solutions of oxygenated halogen acids and metallic salts in that fuller's earth and similar materials while having a marked polymerizing influence have substantially no eflect in respect to reduction in sulphur content. Materials like crushed flrebrlck serve the principal purpose of providing large contacting surface and a spreading or spacing effect on the active reagents. The vapor undergoing treatment may be mixed with oxygencontaining and steam. the former as orineombinationmaybementionedair in the chemical reactions produced by the solu- 7 tion of oted halogen acids andmetallic having beeniound to be particularly eihcacious i in "some instances. 7

In some cases the siliceous contact may be mixed with minor amounts of'materials of a basic nature such as metals or their oxides,.these- 00 resulting in some instances from the decomposition of compounds of the metals incorporated with the earthy. materials, prior to their roasting andin-other instances from the disintegration reactions oithe earthy materials during their use in (i5 the process. The efiect oi the bases may be of. a chemical or-merely of a catalytic nature.

The invention is more particularly directed to thetreatmen't of vapors-oi lower boiling cracked distillates though straight run distillates may also be treated within the scope of the invention. and is also particularly directed towardsthe desulphurization of hydrocarbons and especially cracked hydrocarbons.

The oxygenated halogen acids, the use of which'is comprised in the present invention, have analogous properties to a considerable extent in that they-all exertan oxidizing and some polymerizing action upon cracked hydrocarbon vapors whether dissolved alone in water or dis- SQ' solved along with other salts and alkalies which may have been produced incidentally to the production of the desired acid. It is recognized, however, that they diifer in degree and to some extent in the nature 015 the reactions produced.

The various oxygenated halogen acids which may be produced by conducting chlorine, bromine or iodine into aqueous solutions under suitable conditions provide reagents of varying strength and effectiveness for use in treating cracked vapors particularly when metallic salts are pres:. ent in the solutions. The method of production of these different reagents is quite general and the products may be used in particular casesto produce controllable ts upon a large number of types of cracke vapors of variable composition. The use of fluorine results in instantaneous decomposition of the water with the liberation of highly ozonized oxyg n. thistorming an exception to the general reactions or the other halogens as in many other cases.

In applying the process of the invention to practice any suitable equipment may be 8111- ployed which 'will permit the contacting of them; hydrocarbon, vapors and the treating'reagen'ts" employed with the solid contacting or polymerizing materials; forexampl, a suitable tower or chamber packed with a selected mixture of 0011-.

tact materials maybe employed following tam fractionator of a cracking system, the reagents being introduced at a suitable point or points along the line of flow of the ascending or descending vapors thus permitting contact of the mix- 5 ture of hydrocarbon oil vapors, oxygen-containing gases and steam with the solution ofoxyhalogen acid and metallic salts and the solid contact materials. Similarly any device which permits the efficient contacting .of the hydrocarbon vapors undergoing treatment with gases, liquids and solids may be employed. The solid contacting materials may sometimes be employed in successive strata of varying composition.

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. In cases involving the use of solutions containing only a small excess of the oxygenated acid the excess of acid may be completely consumed so that subsequent neutralization is not necessary.

Reactions involved in treatments comprised within the scope of the invention are of a complicated nature from a chemical standpoint but the net results are in the direction of reduced gum and sulphur content in the treated product. The nature and extent of the reactions with any particular type of hydrocarbon vapors will vary with the amount and nature of the particular oxyhalogen acid and metallic salt solution employed, and also with the amount and type of oxidizing gas mixture and the amount of steam used. It has already been mentioned that the reactivity and treating action of the acids which may be used vary in degree and that while they produce similar efiects that they are not precise equivalents. Temperatures and pressures employed in treating operations may vary over a wide range, and it may be advisable in certain instances to use the less reactive acid than the more reactive to control the extent of polymerization desired. Frequently the element of cost enters into consideration as well. By using varying mixtures of difierent oxyhalogen acids and metallic salts in solution therewith and different oxygen-containing gases, and steam, it has been found possible to produce a wide range of treating effects all tending toward the selective elimination of unsaturated compounds and reduction in sulphur content. The reactions involved when solutions of oxyhalogen acids and metallic salts act upon hydrocarbon vapors are apparently of an oxidizing and polymerizing nature, particularly in the presence of oxygen-containing gases and solid adsorbent materials both of which also assist the reactions. Whatever fixation of halogen occurs seems to be taken care of by the fact that the addition compounds are higher boiling than the original hydrocarbons from which they were formed and as such are left behind as heavy refiuxes during the subsequent fractionation of the treated vapors.

The amounts of reagent used in conducting treatments comprised within the scope of the invention will vary over a wide range depending on the chemical nature of the particular vapors in question, the extent of refining action desired and the efficiency of the particular reagent solution chosen from the standpoint of economy and availability. The use of hypochlorous acid has been shown to be of definite commercial value and experimental results thus far obtained indicate that beneficial results are also obtainable by the use of the more highly oxygenated chlorine acids and corresponding acids of bromine and iodine.

Various temperatures of treatment may be employed, for example, from 250-600" F., 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.

a specific example of a method of treatment comprised within the scope of the invention and the results obtainable therefrom the case of treatment conducted upon vapors of approximate gasoline boiling point range produced in the cracking of a heavy gas oil distillate produced from California crude may be mentioned. Such vapors may be passed upwardly through a mass of moderately fine fullers earth countercurrent to a descending solution containing approximately 3 to 5% free hypochlorous acid and 15% of zinc chloride. The vapors may be mixed with a small amount of air to assist in oxidizing reactions and steam to the extent of approximately 4 lbs. per bbl. of condensed gasoline. The gasoline produced from the vapors without chemical treatment of any kind may have the following properties:

Gravity A. P. I 53.2

Color Yellow Gums by copper dish method 530 mgs. Sulphur 0.43%

After treatment with reagents in the amounts and the manner described the condensed gasoline may be found to have the following properties:

Gravity A. P. I 53.5 Color- 30 Color after 4 hrs. exposure to sunlight 29 Gum 10 mg. Sulphur 0.13%

gasoline of the following properties I Gravity A. P.r 54.3 Color straw yellow Gums by copper dish method 410 mgs. Sulphur 0.39%

When the vapors are subjected to treatment as described prior to their final fractionation, a finished gasoline of the following properties may be produced:

Gravity 54.6 Colon; 30 Color after 4 hrs. exposure to sunlight 29 Gums 5 mg. Sulphur 0.10%

The foregoing specification containing descrip tive material and examples of "the results obtainable by the use of the process of the invention,

have been given for illustrative purposes and while they clearly define the invention and indisisting of hypochlorous acid, chloric acid, bromic acid and iodic acid.

2. A process for refining hydrocarbon vapors which comprises treating the vapors in the presence of adsorbent earth with an aqueous solution containing free hypochlorous acid and a heavy metal salt which is soluble in the solution.

3. In the vapor phase refining of hydrocarbon oils, the step which comprises treating the vapors with an aqueous zinc chloride solution containing free hypochlorous acid.

GUSTAV EGLOFF. JACQUE c. MORREIL.