US1920247A - Treatment of hydrocarbon oils - Google Patents

Description

Aug 1, 1933. R 3 DAY 1,920,247

TREATMENT OF HYDROCARBON OILS Filed June 1931 I NVENTOR ROLAND B. DAY

BY ZWM ATTORNE Patented Aug. 1, 1933 UNITED STATES TREATMENT OF HYDROCARBON OILS Roland B. Day, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, 111., a Corporation of South Dakota Application June 8, 1931. Serial No. 542,738

18 Claims.

This invention relates to the treatment of hydrocarbon oils, and refers more particularly to the treatment of the lower boiling portions of crude petroleum or similar distillates produced in cracking processes.

More specifically the invention has reference to treatment of such low boiling hydrocarbon mixtures by means adapted to controllably reduce their content of unsaturated or gum-forming hydrocarbons and at the same time alter the form of combination of the sulfur to render it less corrosive and more readily adaptable to removal by subsequent treatment.

This application is a continuation-in-part of my earlier copending application Serial No. 488,112, filed October 11, 1930, disclosing vapor phase treatment of hydrocarbon oils with hydrochloric acid in the presence of metal. The present application is also a continuation-in-part of my prior copending applications Serial No. 520,880, filed March 7, 1931, and Serial No. 533,852, filed April 29, 1931, disclosing liquid phase treatment of hydrocarbon oils with hydrochloric acid in the presence of metal.

Various expedients have been adopted in refining practice to accomplish the ends referred to, the most common being the use of sulfuric acid of varying concentrations, this treatment being conducted particularly in the liquid phase upon condensed distillates. A considerable variety of methods have also been utilized to treat the vapors of the oils either prior to their initial condensation or after their revaporization. In this latter category are included treatments which involve the use of solid contact materials of the nature of fullers earth, and also finely divided metals, metal oxides and other contact masses. It is with improvements in treating processes that the present invention is concerned, a chemical and catalytic process being disclosed which is capable of more economically producing results comparable with those produced by previously used methods of treatment.

In one specific embodiment the invention comprises treating hydrocarbon oils either in vapor or liquid phase with hydrochloric acid in the presence of metal or alloys composed of metals representing the groups above and below hydrogen in the electrochemical series.

I have found that better results in the treatment of hydrocarbon oils may be obtained when the oils are treated with hydrochloric acid in the presence of metal alloys of the types mentioned than are obtained when the metals are used separately or in simple admixture, although improvement of the oil is obtained when a simple metal or metal mixture is employed as will hereinafter be seen. For example, in treating the vapors of low boiling cracked oils with hydrochloric acid in the presence of copper, 1 have observed that the copper in addition to acting as acatalyst for polymerization reactions combines to a limited extent with the sulfur present in the vapor, the sulfur uniting with the copper to form copper sulfide and thus gradually removing the copper from the role of catalyst. The copper may also function to change the form of combination of the sulfur according to the reactions involved in the so-called sweetening of oils containing mercaptans, the mercaptan sulfur appearing in the corresponding dialkyl disulfides which are less corrosive than the mercaptans. Further than this, the form of combination of sulfur is sometimes changed in a manner not at present exactly understood so that its reduction is easier by subsequent treatments such as, for example, treatments with sulfuric acid. Both the copper and the copper sulfide are apparently unaffected by the hydrochloric acid vapors, in accordance with the position of copper as a metal below hydrogen in the electro-chemical series.

When finely divided metallic zinc is used alone in place of copper, there occurs along with desired polymerization reactions a certain amount of zinc chloride formation, the effect upon the sulfur content being of a much lower order than in the case of copper. When steam is present in admixture with the oil vapors, (this occurring when the hydrochloric acid has been added in aqueous solution or when steam is otherwise introduced into the sphere of reaction) a certain amount of zinc oxychloride formation may occur.

When copper and zinc are alloyed in varying proportions as in brasses, combinations of treating effects are produced which are less readily obtained with either metal alone. From the results obtained in practice it may be concluded that when the alloys are used the metal sulfides which are initially formed are acted upon by the hydrochloric acid to liberate hydrogen sulfide so that the catalytic mass is automatically and continuously regenerated, and a reduction in sulfur content is effected.

While, as has already been stated, the process may be used either upon hydrocarbon oils as liquids or upon their vapors, it will be sufiicient to describein detail an operation of the process conducted upon hydrocarbon oil vapors since liquid phase operations are more commonly prac-' ticed and more generally understood in the industry and their detailed description is not necessary.

Io assist in describing an operation comprised within the scope of the invention reference is made at this time to the attached drawing, which shows diagrammatically in side elevation one arrangement of equipment in which the process may be carried out.

In the drawing, line 1, containing a control valve 2, represents a line for the admission of hydrocarbon oil vapors from any source such as,

, for example, from the straight or non-cracking distillation of hydrocarbon oil mixtures such as crude petroleum or from the cracking of the heavier or less desirable portions thereof. Va-- pors thus introduced may be conducted to a treat-- ing chamber I either through a line 3. containing a control valve 4, or line 5, containing a control valve 6. In the former event the oil vapors may be admitted to a vapor space 9 above a metallic alloy contact mass 8 and pass downwardly there through, while in the latter event the vapors are introduced into a lower vapor space 10 and pass upwardly through the contact mass, the choice of the direction of flow being determined by the nature of the oils treated and the extent of re-- fining desired, and other factors. The treater 7 may have upper and lower removable manheads l1 and 12, respectively, to permit entry for cleaning or other purposes.

The hydrochloric acid may be introduced either in aqueous solution or as a gas from a source not shown through a line 13 containing a control valve 14 and pass through a line 15, containing a valve 16 and ending in distributing means 16' into the upper vapor space Q or through a line 1'7, containing a valve 18, into lower vapor space 10 through distributing means it, the flow of the acid treating reagent being generally eoncurrent with the iiovv of the vapors in either direction.

The metallic contact mixtures employed in the zone designated by 8 in the drawing may be of a variable composition comprising as previously indicated various alloys of metals occurring above and below hydrogen, respectively, in the electrochemical series. As examples of metals above hydrogen in the series which may be used may be mentioned aluminum, manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin and lead and as examples of those occurring below hydrogen may be mentioned such metals as antimony, bismuth, arsenic, copper and mercury (amab gam). The metals mentioned are in general the commoner and more readily available metals and while it is not intended to exclude metals of a more expensive nature, their use is generally not necessary to produce the results desired. These alloys may be used in space 8 supported upon a perforated false bottom 8' and may be utilized as turnings or as finely divided powders or pellets supported on or mixed with inert siliceous spacing materials such as fullers earth, et cetera.

In the event the treatment is conducted by passing the oil vapors and acid treating reagent downwardly through the metallic contact mass a subsequent fractionation for the removal'oi polymers and; reaction products is necessary, a preliminary or partial separation being effected in vapor space 10 which is competed to a desired degree in a subsequent fractionator. Liquids separating 57in evaporator 10 may be withdrawn through a line 45, containing control valve 46, to an accumulator 4'7 which has a connecting line 48 to prevent vapor lock.

Polymers and reaction products and heavy liquids may be withdrawn from the accumulator through a line 51, controlled by a valve 52, to a pump 53 which in turn may discharge such products through a line 54, controlled by valve 55, to various points depending upon their nature and adaptability to further use in the process. In some instances the polymers may be returned to the original source of vapors introduced to the accuser through a line 19;", containing control valve 20',

and enter a succeeding fractionator 27 through a line 21, containing control valve 22. This free-- tionator may be of any suitable type adapted to the production of the vapors of desired boiling point range which may be released from the top of the tower through a line 28, containing a control valve 29, and pass through a line 30 provided with a control valve 31 to a condenser 32, the cooling effect of which produces a mixture of liquids and fixed gases which then pass through a line 33 having a control valve 34 to a final re ceiver and separator 35. This receiver may have a fixed gas release line 36 having a control valve 37 therein and a liquid end product line 38 having a control valve 39 through which disposal of hm ished oil may be made. To assist in controlling the boiling point range of the vapors emergent from the tower a pump 42 may return a required portion of the liquid condensate to the top of. iractionator i, this pump taking suction on the receiver liquids through a line 40, containing a control valve ll, and discharging through a line 13, containing a control valve id. The liquids or higher boiling range than desired in the finished product and containing material percentages of heavy polymersmay be passed from the bottom of fractionator 2'! through a line 459, containing a control valve 50, to accumulator 47 from which point they are removed along with the heavy liquids from the treater as already described.

When the oil vapors to be treated are introduced into vapor space 10 prior to their passage upwardly through the contact rnass, a certain degree of fractionation may be expected which may at times obviate the necessity of further fractionation. The vapors of approximate end product boiling range may then pass from vapor space 9 through a vapor line i9, containing a control valve 20, and through line 23, containing valve 24, directly to line 30 and through the condenser and receiver as already described in connection with the other mode of operation. If further fractionation should be required, they may pass through a line 25, containing therein a control valve 26, to line 21 leading to fractionator 27 as already described, and thence to the condensing and collecting equipment.

Pressures and temperatures employed in the treatment will vary over a wide range, being at times those dependent merely upon the type of refining operation preceding the treatment or Bil they may be adjusted to suit particular needs.

For example, the vapors may come from a continuous crude oil distilling unit operating at substantially atmospheric pressure, the mean temperature of the vapors under such circumstances being approximately 250 to 300 F., more or less. In other instances the vapors may arise from a. cracking process operating under high superatmospheric pressure such as, for example, in the neighborhood of 300 pounds per square inch, vapors under these circumstances being at a considerably increased temperature in the neighborhood of 500 to 550 F. In still other cases it may be necessary to operate at superatmospheric pressures in order to prevent substantial condensation of admitted vapors during treatment and to treat at lower temperatures. In short,

any range of temperature and pressure may be utilized without departing from the sphere of the invention.

To neutralize corrosive effects the treater itself may be composed of suitable acid resisting metals or lined therewith and neutralizing substances such as, for example, solutions of caustic soda or the vapors of ammonia may be introduced at points subsequent to the treater in the fractionating, condensing and receiving equipment.

When treatments are conducted in liquid phase the finely divided alloys may be suspended in a body of oil contained in a batch agitator and maintained in suspension by mechanical means or by introduction of hydrochloric acid vapors' and the treated oils after sedimentation of solids may be redistilled in subsequent equipment. It may be feasible under some conditions to introduce the finely divided metallic alloy along with an acid treating agent into a tubular heating element wherein they are brought to proper reacting temperatures and then discharge the heated products into separating and fractionating equipment, such a process being well adapted to continuous operation.

An example of the results obtainable by the operation of the process may be given as follows: In the cracking operations on a California residuimi there may be produced a gasoline with a gum content of approximately 400 mgs. per 100 cc. by the copper dish test, this gasoline having a sulfur content of 35% and reacting positive to the doctor test. When such a distillate is subjected to the treatment of the present process using a brass of approximately copper and 25% zinc and hydrochloric acid at the rate of one pound of concentrated or 37% acid per barrel, the gum content of the condensed vapors may be found to be reduced to approximately 25 mgs, with improvement also in color and color stability. The reaction with doctor solution may be found to be negative though the sulfur content is only sli htly reduced to approximately 0.3%. When operations are conducted with the same amount of hydrochloric acid but with copper in place of brass, the gum content may be reduced to approximately 4.0 to 50 mgs, a corresponding point being reached using zinc in place of copper. In either case where the metals are used singly the sulfur content of the product may be found to be practically the same as in the untreated distillate and the doctor test may still be positive though not as strongly so as in the untreated or raw distillate. These results serve to indicate that there is an increased effect produced when the metals are alloyed over that produced when they are used separately.

The foregoing description and example have indicated that the present invention comprises a process marking a distinct improvement in processes of treating hydrocarbon distillates. However, since the description and example given are illustrative merely, and since many other modes of operation with corresponding variations and results may be given, those stated above are not to be construed in a limiting sense.

I claim as my invention:

1. A process for refining hydrocarbon oils which comprises treating the oil with added aqueous hydrogen chloride in the presence of a free metal selected from the group consisting of aluminum, manganese, zinc, chromium, iron cadmium, cobalt, nickel, tin, lead, antimony, bismuth, arsenic, copper and mercury.

2. A process for refining hydrocarbon oil which comprises treating vapors thereof with added aqueous hydrogen chloride in the presence of a solid contact mass containing a free metal selected from the group consisting of aluminum, manganese, zinc, chromium, iron cadmium, cobalt, nickel, tin, lead, antimony, bismuth, arsenic, copper and mercury.

3. The process as defined in claim 1 further characterized in that the oil is treated with the aqueous hyrogen chloride while substantially in liquid phase.

4. A process for refining hydrocarbon oils which comprises treating the oil with added aqueous hydrogen chloride in the presence of a solid material containing both zinc and copper.

5. A process for refining hydrocarbon oil which comprises treating vapors thereof with added aqueous hydrogen chloride in the presence of a solidcontact mass containing both zinc and copper.

6. The process as defined in claim 4 further characterized in that the oil is treated with the aqueous hydrogen chloride while substantially in liquid phase.

7.,The process as defined in claim 4 further characterized in that said solid material comprises brass.

8. The process as defined in claim 5 further characterized in that said contact mass comprises brass.

9. A process for refining hydrocarbon oils which comprises treating the same while substantially in liquid phase with added aqueous hydrogen chloride in the presence of brass.

10. A process for refining hydrocarbon oils which comprises treating the oil with added aqueous hydrogen chloride in the presence of mm.

11. A process for refining hydrocarbon oils 115 which comprises treating vapors thereof with added aqueous hydrogen chloride in the presence of zinc.

12. A process for refining hydrocarbon oils which comprises treating the same while substantially in liquid phase with added aqueous hydrogen chloride in the presence of zinc.

13. A process for refining hydrocarbon oils which comprises treating the oil with added aqueous hydrogen chloride in the presence of copper.

14. A process for refining hydrocarbon oil which comprises treating vapors thereof with added aqueous hydrogen chloride in the presence of copper.

15.A process for refining hydrocarbon oils which comprises treating the same while substantially in liquid phase with added aqueous hydrogen'chloride in the presence of copper.

16. A process for refining gasoline-containing distillates which comprises treating the same with added aqueous hydrogen chloride in the presence of metallic zinc.

17. A process for refining gasoline-containing distillates which comprises treating the same with added aqueous hydrogen chloride in the presence of metallic copper.

18. A process for refining gasoline-containing distillates which comprises treating the same with added aqueous hydrogen chloride in the 145 presence of brass.

ROLAND B. DAY.

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