US2063491A - Treatment of hydrocarbon oils - Google Patents

Description

Dec. 8, 1936. v R. B. DAY 2,063,491

TREATMENT OF HYDROCARBON OILS Original Filed June 15, 1931 FRACTIONATOR 35 /FRACTIQNATOR CON NSER 3| INVENTOR ROLAND B. DAY

BY Maw AT TORN Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE 2,063,491 TREATMENT OF HYDROCARBON OILS Roland B. Day,

assignments, to pany, Chicago, 111.,

Chicago, 111., assignor, by mesne Universal Oil Products Coma corporation of Delaware Application June 15, 1931, Serial No. 544,373 Renewed June 19, 1935 Claims.

This invention relates to the treatment of hydrocarbon oils and refers more particularly to the treatment of the light distillates produced in the gum-forming constituents, to sweeten them and to a considerable extent desulphurize them.

In one specific embodiment prises treating cracked hydrocarbon vapors hydrochloric acid in the invention comwith the presence of solid contact materials containing a combination of solid metallic salts comprising mixtures of the chlorides of Zinc and mercury of a nature adapted to polymerize the more highly unsaturated components and react continuously upon sulphur compounds without substantial deterioration, the treated vapors being subsequently fractionated to remove reaction products and polymers boiling above the range of the end product desired.

The lighter vapors from cracking operations containing substantial amounts of gasoline components are usually characterized by a varying content of unsaturated hydrocarbons and also of more or less odorous pounds. sitated by the use of the original method and corrosive sulphur com- To reduce these groups to a point necesthe distillate as motor fuel, employed was to treat the condensed distillate with alkalies and sulphuric acid and redistill to produce a gasoline of desired end point and other physical and chemical properties.

Such refining operations have numerous inherent disadvantages such as the cost of reagents and the fact that the treated distillate must be revaporized ucts formed in the to leave behind heavy prodtreatment thus occasioning a loss of heat originally contained in the vapors.

The present process:

is concerned with the treatment of cracked vapors prior to their condensation to economically effect the necessary degree of refinement required by commercial specifications for motor fuels.

The attached drawing used to assist in describing an prised within the sec plaining the details of the process.

side elevation by the may conveniently be operation com.- pe of the invention and ex- It shows in use of conventional figures an arrangement of equipment consisting essentially of a fractionator 3 for the production of vapors of approximate motor fuel boiling point range, a treater 1i! i n which they are subjected to refining treatment characteristic of the present invention and a fractionator 21' followed by the usual condensing and collecting equipment.

In the drawing a line I containing a control valve 2 may be assumed to be a source of vapors from a cracking process of any type, these: vapors entering a fractionator 3 which has a vapor line 6 containing a control valve 1 and a liquid draw line 4 containing a control valve 5 for the removal of heavy refluxes which may or may not be returned to the heating element of the cracking process for further treatment. The vapors from the fractionator may pass through line 6 and vaive l and enter the treater either above or below the solid contact materials dependingupon their particular nature, temperature and pressure conditions, the amounts of reagents used, the properties desired in the finished product, etc. In the vapor phase treater 10 a contact mass is maintained in space 13 included between the perforated false bottom 13' and the upper dotted line and since the proper composition of this mass is a specific feature of the present invention it will be described in some detail.

In previous copending applications I have disclosed processes involving the treatment of cracked vapors with hydrochloric acid in the presence of various metallic contact materials such as, for example, zinc, copper, mercury and alloys such as brasses. In these previous applications I have shown that polymerizing and sweetening effects are obtained by the use of hydrochloric acid and selected metals, metal alloys, etc., though the amount of overall sulphur reduction effected is somewhat limited. In processes of this type employing metallic copper, brasses or other metal alloys or mixtures and hydrochloric acid, the efficiency of the metalliccontact mass is slowly lost due to the formation of superficial layers of sulphides, this action being, of course, proportional to the amount of sulphur in the entering vapors and particularly to the proportion of hydrogen sulphide which they contain. I have now found that by the use of a certain selected combination of metallic salts in the vapor phase treatertthat the metallic sulphides or other organic sulphur addition compounds originally formed are continuously decomposed by the hydrochloric acid with the liberation of hydrogen sulphide so that the sulphur content of the entering vapors has substantially no permanent efiect upon the contact mass which therefore may be used over long periods of time without removal. I have found that these results are obtained by the use of mixtures of chlorides of zinc and mercury.

As to the mechanism of thereactions involved,

of the acid into lower vapor space have a vapor line the treater it is probable that transitory addition compounds are formed between the mercuric chloride and sulphur derivatives in the entering vapors since it is known, for example, that direct addition compounds are formed by the mercury compounds and mercaptans, this fact having given rise to the name mercaptan. The salts in question may be conveniently incorporated with relatively inert materials such as diatomaceous earth, sand, powdered glass or porcelain, etc., either as dry salts or in concentrated aqueous solutions which are then sufficiently dehydrated by heat and the mass reduced to the proper dimensions for use in the tower.

Referring again to the drawing, hydrochloric acid preferably in aqueous solution of regulated concentration may be introduced to the system from a source not shown through a line l6 containing a control valve H and leading to a pump 58 which discharges through a line l9 containing control valves 20 and 2B. A branch line 2| containing a control valve 22 permits introduction i 5 of the vapor phase treater while the use of valve 20' with valve 22 closed permits the introduction into the upper vapor space i 4. In the event that downflow treatment is chosen as being best suited to the case in hand the fractionated hydrocarbon vapors may be admitted to upper vapor space I4 in the treater from line 8 containing control valve 9 along with a regulated amount of hydrochloric acid, the Vapors and acid then passing downwardly through the contact mass containing the salts. Since this downfiow treatment results in substantially no fractionation of the vapors but only a rough separation of heavy polymers and reaction products in lower vapor space l5 it will be necessary to utilize the subsequent fractionator, and the vapors from this lower space below the perforated false bottom may be conducted through line 23 having therein a valve 24 and a line 25 having a control valve 26 into fractionator 21 in which final rectification is conducted to produce a finished product. This fractionator may 28 containing a control valve 29 which joins with the line 30 containing control valve 30' which conducts the vapors of desired :boiling point range and fixed gases to a condenser 3| which liquefies the condensible portions and lpasses the liquids along with the fixed gases through a line 32 containing a control valve 33 .to a receiver 34 in which separation of liquids and fixed gases is efiected, the former being withdrawn through a line 31 containing a control valve 38 to storage and the latter being released through a line 35 containing a valve 36 at a rate consistent with the maintenance of suitable back pressure upon the equipment. To assist in controlling the boiling point range of the vapors from the tower a certain portion of the condensed distillate may be recirculated by means of a pump 4| which takes suction on a required amount of the condensed liquids through a line 39 containing control valve 40 and discharges them back into the top of the fractionator through a line 42 containing a control valve 43.

Heavy polymers and at times minor amounts of salt solutions which accumulate in the bottom of treater l may be conducted therefrom through a line 50 containing a control valve (with cooling if desired by means not shown in the drawing) to an intermediate accumulator 53,

this accumulator having a vapor connecting line 52 to prevent gas lock and insure easy flow from to the accumulator. Heavy liquids from the fractionator may pass to the same at:- cumulator through a line 54 controlled by a valve 55. A pump 58 may be provided to dispose of the liquid accumulations in accumulator 53, this pump taking suction when necessary through line 56 containing valve 51 and discharging the liquids to a suitable point of disposal through discharge line 59 containing control valve 60.

Upward flow treatments involving a partial fractionation of the entering vapors may be conducted by admitting the vapors from fractionator 3 to lower vapor space through valve 1, valve 9 being closed, with hydrochloric acid admitted through branch line 2| containing valve 22, this type of treatment being selected with due regard to the time factor involved and other considerations. In this event the vapors and gases produced may leave upper vapor space I4 of the treater through line 44 containing control valve and pass either directly to the condensing equipment already described by way of line 46 containing control valve 41 and line 30 as already described, or if further fractionation is desired or necessary they may be diverted through a line 48 containing a valve 49 and pass through the same general fractionating step already described in connection with the down-flow method of operation.

Treater i G is provided with upper and lower removable manheads H and 12 to permit easy entry for the introduction of fresh or the removal of spent contact materials.

Temperatures and pressure employed in the process will necessarily vary over a considerable range, the process not being limited in respect to either. However, treatments of high efiiciency may be obtained at temperatures within the range of 200 to 500 F. more or less at pressures from atmospheric to 200 lbs., per square inch or higher. In a considerable number of cracking plants the final fractionator corresponding to 3 in the drawing is operated at pressures somewhat lower than that obtaining in the cracking zone and frequently of an order of 75 to 100 pounds per square inch and it has been found that vapor phase treatments may be efficiently conducted within this range.

It will be obvious that the maintenance of proper concentration of hydrochloric acid is essential to best results since on the one hand completely anhydrous reactions which might be produced by use of dry hydrochloric acid gas are not particularly eificient and on the other hand if too much water is present from the use of relatively dilute solutions, the solid salts and gradually removed from the sphere of reaction. Furthermore the cooling effect from the use of large amounts of dilute acid may be considerable and cause an undesirable amount oi condensation in the treater. To maintain proper concentrations of acid solution, steam or water may be admitted if the case requires it. Air may also be admitted at times to produce a mild oxidizing effect.

If necessary in preventing corrosion, the treater and subsequent portions of the vapor phase treater may be constructed of suitable acid-resisting metals or may be copper lined, or if ordinary steel equipment is used. either ammonia or other alkalies may be introduced to neutralize any acidic substances present in the vapors from the treater.

While the process is frequently all that is re quired to produce a finished gasoline from cracked vapors it may be at times advantageous may be dissolved to either precede or follow the treatment disserve to show that the process of the invention is closed with other treatments of a more generally one of great value to the oil industry but the deused character. scriptive material is more or less specific in re- Examples of the results produced by operagard to the drawing and example and it is not to 5 tions comprised within the scope of the invention be understood that these are to act as limitations 5 might be multiplied to a considerable extent but upon the broad scope of the invention. the following will be sufficient to indicate its I claim as my invention: commercial advantages. It may be found that l. A process for refining cracked distillate the raw gasoline produced by merely fractionatwhich comprises treating the same at a tempering the vapors from the cracking of a Mid-Contiature between 200 F. and 600 F. with aqueous l0 nent fuel oil to produce a desired end point prodhydrogen chloride solution in the presence of a uct has a sulphur content of a 0.45% and consolid mixture of zinc chloride and mercury tains gums to the extent of 400 mgs. per 100 ccs. chloride. by the copper dish method. By passing such va- 2. A process for refining hydrocarbon oil pors mixed with hydrochloric acid at the rate of which comprises treating the oil with added 15 2 pounds per barrel of condensate over diatomaaqueous hydrogen chloride in the presence of ceous earth impregnated with zinc chloride and solid zinc chloride.

mercury chloride in the ratio of four parts of zinc 3. A process for refining cracked distillate chloride to one part of mercuric chloride with which comprises treating the same at a temperdue regard to the time factor while passing over ature between 200 F. and 600 F. with added 20 the contact mass, the sulphur content in the finaqueous hydrogen chloride in the presence of ished gasoline cut may be reduced to as low as solid zinc chloride.

0.15% or lower, the gums then being approxi- 4. A process for refining hydrocarbon oil which mately 20 mgs. After a light caustic Wash which comprises treating the same in vapor phase with may be conveniently conducted by adding adilute added aqueous hydrogen chloride in the pres- 25 aqueous solution to the condenser preceding the ence of solid zinc chloride.

final receiver, the gasoline condensate may be 5. A process for refining cracked hydrocarbon found to have a color close to on the Saybolt vapors which comprises treating the same with scale and conform in all respects to the requireadded aqueous hydrogen chloride in the presence 30 ments of a premium gasoline. of solid zinc chloride and solid mercury chloride. 30

The foregoing description and example will ROLAND B. DAY.

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