US1945114A - Method for refining hydrocarbon oils - Google Patents

Description

Jan. 30, 1934. A. LACHMAN METHOD FOR REFINING HYDROCARBON OILS Filed Feb. 25, 1932 MaparOuf/ef 23 INVENTOR ATTORNEY Patented Jan. 30, 1934 UNITED STATES PATENT OFFICE Arthur Lachman, Berkeley, Calif., assignor to Vapor Treating Processes Inc., Los Angeles, Calif., a corporation of California Application February 23, 1932. Serial No. 594,477

13 Claims. (01. 196-36) substantially higher than 350-360 degrees F., for

This invention relates to an improved method and apparatus for purifying and refining hydrocarbon oils obtained by distillation or cracking of mineral oils, such as lamp oil distillates,

naphtha or gasoline stocks, or distillates derived from shale oil, and more specifically refers to the treatment of gasoline or naphtha stocks produced by cracking higher boiling petroleum oils or distillates derived from crude petroleum oil in which hydrogen sulphide, mercaptans and other sulphur bearing compounds, as well as varying percentages of unstable hydrocarbons of the diolefine or acetylene type may be present or formed during said distillation or cracking operation.

This application an improvement in the method described in my United States Patent 1,790,622, granted January 27, 1931, for Method of refining mineral oils, and United States Patent 1,809,170, granted June 9, 1931, for Process of refining hydrocarbon oils, which disclose methods for treating hydrocarbon oils in vapor phase with water solutions of the metallic salts of zinc, copper, cadmium, mercury, iron, chromium, manganese, aluminum, nickel or cobalt, which may be the chloride, bromide, iodide, sulphate, nitrate, and also any of the water soluble salts of the above named metals of organic acids, such as the sulphonic acid of benzol, toluol and xylol, or the sulphonic acid derived from the treatment of petroleum oils with sulphuric acid.

The method described in my aforesaid patents for treating hydrocarbon oils comprises, passing the oil, such as gasoline stock, in a vapor state through and in contact with a hot, substantially concentrated water solution of any of the aforesaid metallic salts or mixtures thereof, in which a tower or concentrator filled with contact'material and a substantially concentrated water solution of the metallic salt is employed.

Under the usually prevailing conditions of treating vapors by this process, and more especially when applied to the treatment of vapors directly from cracking plants, the Vapors have been supplied to the treater at temperatures around 350-360 degrees F. It has also been found that the preferred concentration of zinc chloride solution for treating purposes is between 75 and 85 per cent, and that when concentrations above 85 per cent are employed, the metallic salt (in this case zinc chloride) is approaching an anhydrous condition, with diminished efficiency in treatment.

\Recently, treating conditions have arisen in which the vapors are supplied at temperatures example, 410 degrees F. At this higher temperature more water or steam is required to maintain the zinc chloride concentration below the upper limit of 85 per cent. As an example, if the vapors are being supplied at a temperature of 410 degrees F., and it is desired that the concentration of a metal-salt solution such as zinc chloride shall not exceed 82 per cent, it is necessary to operate the vapor phase treating process at a gauge pressure of not less than pounds, and to supply pounds of water vapor or steam per barrel of gasoline being treated.

If, however, the gasoline vapors are cooled to 360 degrees F. without partial condensation, then the zinc chloride solution in the treating tank may be maintained at a concentration at 82 per cent at a gauge pressure of approximately 28 pounds by supplying not more than 20 pounds of steam or water vapor per barrel of liquid gasoline stock being treated.

The economical advantages of operating with a smaller steam supply are obvious, and furthermore an apparatus operating at 28 pounds gauge pressure can be more economically constructed than one whose working pressure is 40 pounds or more.

Now I have discovered that a reduction in temperature without partial condensation of oil vapors, described above as desirable and economical, can be accomplished by first contacting the hot vapors coming from a cracking or distillation operation at temperatures of, say, 400-410 degrees F., with a cooler water solution of zinc chloride having a concentration of approximately 50 per cent. By regulating the rate of flow of the zinc chloride solution and hot oil vapor passing through a contact tower, the temperature of the oil vapor may be reduced to any desired degree, such for example as 360 degrees F., and at the same time the zinc chloride solution can be concentrated to the desired degree, ranging from '75 to 85 per cent, and thereafter employed for retreating the oil vapors at the reduced temperature. The water evaporated from the zinc chloride solution reduces the partial pressure of the gasoline vapors as their temperature is being reduced and thus maintains them in the vapor state.

An object of the invention is to efiect a purification of petroleum oil products in vapor phase at a desired temperature by contacting the same with a water solution of a metallic salt at a desired concentration.

Another object of the invention is to concentrate a water solution of a metallic salt to a required degree, and then use the concentrated solution of the metal salt in a continuous system, without substantial decrease in temperature, to purify petroleum oil products in vapor phase by contact therewith.

Various other objects and advantages of the present invention will be apparent from the description of the preferred form, or example of the method and apparatus embodying the invention. For this purpose reference is made to the accompanying drawing, in which there is illustrated a form of apparatus in which the invention may be performed.

The drawing represents a diagrammatical view of apparatus in which the parts are in sectional elevation.

Referring to the drawing, 1 represents generally, a vapor pipe which leads to a source of oil vapor coming from a cracking or distillation operation of petroleum oil, not shown, at temperatures of approximately 400-410 degrees F. Pipe 1 is connected to the lower section'of contact tower or concentrator 2, which is stationed in the upper section of a steel shell or cylinder 3. Contact tower or concentrator 2 is filled with resistant or contact material, such as cobble stones, fire brick, spiralv tile or the like, indicated at 4, and supported by a grid 6.

A pipe 5 connects concentrator 2 at the top to a lower section of contact tower 9, indicated at 10. Pipe '7, controlled by valve 8, is connected to concentrator 2 at the bottom and leads to a source of steam not shown. Pipe 11, provided with a U bend, connects concentrator 2 near the top to contact tower 9. Inlet pipe 12, controlled by valve 13, connects concentrator 2 below grid 6 to pipe 14. Pipe 14, controlled by valve 15, is connected to contact tower 9 near the top, and leads to a source of metallic salt solution supply, such as zinc chloride, not shown.

Contact tower 9 is provided with a plurality of bubble trays 16 and over flow pipes 17. 18 indicates a gauge glass attached to contact tower 9 near the bottom, by means of which the liquid level in contact tower 9 may be observed. Pipe 19, controlled by valve 20, connects contact tower 9 to a source of steam supply not shown. Pipe 21, controlled by valve 22, connects contact tower 9 at the bottom to a recovery storage not shown. A vapor outlet pipe 23 connects contact tower 9 at the top to a condenser and receiver not shown.

The preferred operation as carried out in the apparatus just described is as follows:

Concentrator 2 is filled to the top of the con- A tact mass with a water solution of the metallic salt treating agent, which may have a concentration of, say, per cent in case zinc chloride is employed, by opening valve 13 in pipe 12. Pipe 12 is connected to pipe 14 and leads to a source of supply.

Mineral oil vapors, such as a gasoline stock coming from a distillation or cracking operation, at a temperature of, say, 400-410 degrees F., at a gauge pressure of, say, approximately 28 pounds, pass through pipe 1 and into the bottom of concentrator 2 below grid 6. The heated oil vapors pass up through contact mass 4. and water solution of the treating agent into pipe 5, by means of which the treating agent is heated and concentrated to the desired degree, which is approximately 82 per cent when zinc chloride is employed.

When the treating agent in concentrator 2 has reached the desired concentration, valve 13 in pipe 12 is opened to the required degree so as to admit a regulated continuous flow of the treating agent into concentrator 2, such flow being governed by the rate of concentration of the metallic salt solution, which may be accelerated by preheating the solution before it enters concentrator 2., or by the introduction of superheated steam by a regulated opening of valve 8 in pipe 7.

From concentrator 2 the metallic salt solution, concentrated to the required degree, over flows into pipe 11 and passes into contact tower 9, keeping bubble trays 16 filled to the top of the over flow pipes 17, the excess solution continuously passing in succession from tray to tray through pipe 5 into the lower section of contact tower 9, then up through bubble trays 16, wherein the oil vapors are contacted with the concentrated treating agent and purified to the required degree.

In order to maintain a uniform temperature and a uniform degree of concentration of the treating agent, steam may be introduced into-contact tower 9 by a regulated opening of-valve 20 in pipe 19. Also a dilute solution of the treating agent may be continuously or intermittently in- I tro'duced into the top bubble tray of contact tower 9 to regulate the concentration of the treating agent, by a regulated opening of valve 15 in pipe 14, so as to maintain a substantially uniform concentration on all the bubble trays.

While the method and apparatus herein described is well adapted for carrying out the objects of the present invention, it is to be understood that various modifications and changes may be made without departing from the spirit of the invention, such, for example, as the use of other forms of-concentrators and contact towers, and the invention includes all such modifications and changes as appear within the scope of the appended claims.

I claim:

I. In a process of treating gasoline vapors at elevated temperatures with metallic salt solutions, the method of insuring the intermingling of vapors at optimum temperature with a solution of optimum concentration without sacrificing heat economy which comprises contacting a metallic salt solution of less than optimum concentration for production of final desirable results with gasoline vapors at a temperature in excess of the optimum temperature at which said vapors should be contacted with the solution of optimum concentration, and thereafter recontacting the cooled gasoline vapors with the metallic salt solution of resulting higher concentration.

2. In the process of treating gasoline vapors at elevated temperatures with metallic salt solutions, the method of insuring the intermingling of vapors at optimum temperature with a solution of optimum concentration without sacrificing heat economy which comprises contacting a weak solution with gasoline vapors at elevated temperature to reduce the temperature of said vapors and thereafter performing final treatment by contacting the cooled vapors with the solution concentrated by the aforesaid initial contacting.

3. In the process of treating gasoline vapors at elevated temperatures with metallic salt solution of optimum concentrations, the method of effecting desirable heat economies which comprises utilizing the initial elevated temperatures of said vapors to increase the concentration of a treating solution and thereafter efiecting final treatment by contacting the solution of increased concentration with the vapors whose temperatures have been reduced.

4. In the process of treating gasoline vapors at elevated temperatures with metallic salt solution of optimum concentrations, the method of effecting desirable heat economies which comprises contacting vapors of reduced temperatures with solutions of increased concentration thereby to treat said vapors at their optimum temperatures with a solution of optimum concentration without initially sacrificing heat economy to obtain said concentration and cool said vapors.

5. In the process of treating gasoline vapors at elevated temperatures with metallic salt solution of optimum concentrations, the method of effecting desirable heat economies which comprises utilizing a temperature reducing solution of metallic salt initially to treat the gasoline vapors, and thereafter treating said vapors with the solution at the concentration obtained by said first step.

6. In a process of treating gasoline vapors at elevated temperatures with metallic salt solutions, the method of insuring the intermingling of vapors at optimum temperature with a solution of optimum concentration without sacrificing heat economy which comprises contacting a metallic salt solution of less than optimum concentration for production of final desirable results with gasoline vapors at a temperature in excess of the optimum temperature at which said vapors should be contacted with the solution of optimum concentration thereby to reduce the partial pressure of the gasoline vapors with the water evaporated as the solution is further concentrated by the aforesaid contacting and as the temperature of the vapors is being reduced, wherefrom to maintain the gasoline in vapor phase, and thereafter reeontacting the cooled gasoline vapors with the metallic salt solution of resulting higher concentration.

7. In a method of treating gasoline vapors at elevated temperatures with metallic salt solutions, the process of insuring treatment under optimum conditions without substantial decrease in temperatures which comprises initially in contacting the vapors at elevated temperature with solutions of metallic salts at reduced concentrations thereby to increase the concentration of said solution and reduce the temperature of the vapors to permit desirable subsequent contact between said increased concentrate solutions and said reduced temperature vapors for purification treatment of said vapors.

8. In the process of treating petroleum products in the vapor phase with metallic salt solutions, the process of initially contacting a solution of weak concentration with vapors at elevated temperatures thereby to lower the temperature of said vapors and increase the concentration of said solution to optimum values for final treatment, thereafter contacting the vapors at said lower temperature with the solution of increased concentration, and controlling the concentration of the solution during said second. step by supplying solution to weak concentration as required.

9. A process of purifying mineral oil vapors, comprising, contacting vaporized mineral oil with a dilute water solution of metallic salt, at a temperature sufficient to concentrate the metallic salt solution and effect a partial purification of the oil vapor, then recontacting the partially purified oil vapor with the hot concentrated metallic salt solution produced to complete the purification of the oil vapor, and finally separating purified oil vapor from products of reaction and excess treating agent.

10. A process of purifying mineral oil vapors, comprising, contacting vaporized mineral oil with a water solution of zinc chloride having a concentration of less than per cent, at a temperature sufficient to concentrate the zinc chloride solution to 75-85 per cent and effect a partial purification of the oil vapor, then recontacting the partially purified oil vapor with the hot concentrated zinc chloride solution produced to complete the purification of the; oil vapor, and finally separating purified oil vapor from products of reaction and excess treating agent.

11. A process of purifying mineral oil vapors, comprising, contacting mineral oil vapor, at temperatures of approximately eon-410 F., with a water solution of zinc chloride having a concentration of approximately 50 per cent, to partially purify the oil vapor, concentrate the zinc chloride solution to approximately 82 per cent and reduce the temperature of the oil vapor to approximately 350368 R, then recontacting the oil vapor with the hot concentrated zinc chloride solution produced to complete the purification of the oil vapor, and finally separating purified oil vapor from products of reaction and excess treating agent.

12. A process of purifying mineral oil vapors, comprising, contacting mineral oil vapor, at temperatures of approximately lilo-410 F., with a water solution of zinc chloride having a concentration of approximately 50 per cent, to partially purify the oil vapor, concentrate the zinc chloride solution and reduce the temperature of the oil vapor to approximately 350-360 F., then recontacting the oil vapor with the hot zinc chloride solution produced, maintained at a concentration of approximately 82 per cent by'the continuous addition of steam, to complete the purification of the oil vapor, and finally separating purified oil vapor from products of reaction and excess treating agent.

13. A process or purifying gasoline vapors, comprising, contactin. gasoline vapors, at a tem perature in excess of the optimum temperature at which the vapors should be contacted with metallic salt solution of optimum concentration for producing a complete purification thereof,.

with a metallic salt solution of less than optimum concentration which should be used for producing complete purification of the vapors, thereby partially purifying and cooling the vapors to the optimum treating temperature and concentrating the metallic salt solution to the optimum degree, then reoontacting the cooled vapors at optimum temperature with the produced metallic salt solution of optimum concentration to complete the purification of said va- 2'. TI

pors, and finally separating purified gasoline vapors from products of reaction and excess treating agent.

ARTHUR LACHMAN.

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