US2035609A - Process of purifying and refining hydrocarbon oils with copper salts - Google Patents

Description

March 31 1936. A, H N 2,035,609 PROCESS OF PURIFYING AND REFINING HYDROCARBON OILS WITH COPPER SALTS Original Filed July 26, 1929 2 Sheets-Sheet 1 0/5774077/0 ran 5x2 25 AA'HTER INVENTOR A, LACH'MAN PROCESS OF PURIFYING AND REFINING HYDROCARBON OILS WITH COPPER SALTS March 31,1936.

OriginaiI Fil ed July26; 1929 2 Sheets-Sheet 2 INVENTOR kuOkm Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE- PROCESS OF PURIFYING AND REFININ G HY- DROCARBON OILS WITH COPPER SALTS Arthur Lachman, Berkeley, Calif., assignor to Vapor Treating Processes, Inc., Los Angeles, Calif., a. corporation of California Claims.

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

5 gasoline or naphtha stocks, or distillates derived from shale oil, and more specifically refers to the treatment of gasoline or naphtha stock produced by cracking crude petroleum oils or distillates derived from relatively high sulphur hearing mineral oils, in which hydrogen sulphide, mercaptans and other sulphur bearing compounds, as well as varying percentages of oxygenated hydrocarbons and unstable hydrocarbons (such as diolefines and acetylenes) may be present or formed during said distillation or cracking operation.

This application is a division of my application Serial No. 381,305, filed July 26, 1929, for Process of purifying and refining hydrocarbon oils. 20 Reference is made to United States Patent No.

1,809,170, granted June 9, 1931, to Arthur Lachman, Serial No. 361,513, filed May 8, 1929, for Process of refining hydrocarbon oils, which discloses a vapor phase method or process for purifying and refining mineral oil products with a water solution of certain metallic salts, or mixtures of the same, such as zinc, copper cadmium, mercury, iron, chromium, manganese, aluminum, nickel or cobalt water soluble salts which may be the chloride, bromide, iodide, sulphate, sulphite, nitrate and also any of the water soluble salts of the above named metals of organic acids, such as the sulphonic acids of benzol, toluol and xylol, or the sulphonic acids derived from the treatment of petroleum oil with sulphuric acid.

For the purposes of simplifying the description of my invention, reference will be made mainly to gasoline stock. Crude gasoline stocks obtained by distillation or cracking petroleum oils consist of a mixture of saturated and unsaturated hydrocarbons, together with sulphur compounds, nitrogen bases and other substances of an undefined nature. These latter substances are readily oxidizable at ordinary temperature and are usually responsible for the change of color which takes place when refined gasoline is stored. These oxidizable substances are removed with difficulty when gasoline stocks are treated by the methods known in the art.

By well-known methods, crude gasoline stocks obtained by distillation of crude petroleum oil, or by cracking a higher boiling petroleum oil, are customarily treated with approximately from 1 percent to as high as 8 percent or higher by weight, sulphuric acid, the quantity of sulphuric acid depending upon the nature of the gasoline stock to be treated and the degree of refinement desired. This acid treatment usually consists in commingling the gasoline stock with the required amount of sulphuric acid necessary to obtain the desired extraction, either by the wellknown batch or continuous treatment, after which the products of the acid reaction are permitted to settle and are then withdrawn from the treated gasoline stock. The acid treated gasoline stock is then neutralized by washing with a water solution of an alkali and finally with water. This treatment removes most of the impurities, but subsequent treatments are usually necessary to deodorize and remove or convert corrosive sulphur compounds into non-corrosive bodies.

For this purpose, a water solution of sodium plumbite or sodium hypochlorite is usually employed to render the gasoline stock sweet to the doctor test. In these treatments, particularly where hypochlorite of soda is employed, chlorinated hydrocarbons may be formed to a small extent, which may be converted into corzosive compounds during a subsequent distilla ion.

The general objections to a treatment of this character are as follows: (1) Gasoline purified by this method frequently becomes discolored when stored for a period of time; (2) considerable quantities of sulphuric acid are required, which are difiicult to recover; (3) as high as 10 percent of the valuable unstable hydrocarbons contained in the gasoline stock may be lost; and (4) the treatment must frequently be followed by a sweetening process, such as that heretofore described.

Now, I have discovered that the sulphuric acid normally used to treat crude gasoline stocks may be reduced to a great extent, and in many cases may be entirely eliminated by the employment of a water solution of certain metallic salts, or mixtures of the same, which may be zinc, copper, cadmium, mercury, iron, chromium, manganese, aluminum, nickel or cobalt water soluble salts such as the chloride, bromide, iodide, sulphate, sulphite, nitrate, nitrite, and also'any of the water soluble salts of the above named metals of organic acids, such as the sulphonic acids of benzol, toluol and xylol, or the sulphonic acid salts derived from the treatment of petroleum oils with sulphuric acid.

The process, described briefly, consists in passing the hydrocarbon oil product, such as gasoline stock, in a liquid phase, commingled with a substantially concentrated water solution of any of the above named salts or mixtures thereof, through a heating coil under a pressure sufficient to prevent any substantial vaporization therein, at temperatures of approximately 300 to, 600 ,degrees F., and then immediately releasing the pressure and separating by distillation the purified hydrocarbon oil product from the water solution of the metallic salt or salts, the extracted impurities and products of polymerization or condensation; or, as shown in Figure II, the gasolline stock and water solution of metallic salt or salts may be first separately heated and then commingled under a pressure.

The hydrocarbon oil stock to be treated by my invention may or may not have had a preliminary treatment with sulphuric acid, or other agents to partly purify the same, or may be first partly purified by my invention and thepurification completed by methods known in the art, such as treatment with caustic alkali, sulphuric acid, etc. In the case of gasoline stocks produced by cracking high sulphur bearing crude petroleum oil or residuums, it may be advantageous to treat such gasoline stocks with sulphuric acid or sulphuric anhydride at low temperatures, rangingfrom approximately to 30 degrees F., before the treatment with a concentrated water solution of any of the aforesaid water soluble metallic salts at the elevated temperatures and pressures heretofore stated, and this treatment may also be followed by treatment with an alkaline water solution of sodium, potassium, or calcium hydroxide, or the carbonates of sodium or potassium.

Although a solution of less concentration may be employed, which may range from 50 'or less to approximately 85 per cent, the strength of the I water solution of the metallic salt or mixtures 300 to 600 degrees F., followed by a distillation and fractionation operation to separate the products of reaction and higher boiling polymerized products from the purified gasoline or naphtha stocks.

Another object of the invention is to provide a continuous, rapid and economical process for purifying gasoline stocks produced by the thermo decomposition of higher boiling petroleum oils, by treating the same, under super-atmospheric pressure sufficient to maintain a liquid phase, with a substantially concentrated water solution of a metallic salt, at temperatures of approximately 300 to 600 degrees F.,'to polymerize substantially all the unstable hydrocarbons contained therein, and at the same time remove oxygenated hydrocarbons and render the gasoline sweet to the doctor test.-'

Another object of the invention is to provide a continuous, economical method forimproving the color and removing gums and gum forming material from gasoline or naphtha stock, so that the same may be kept in storage for relatively long periods of time without changing color or quality by the formation of polymerized bodies.

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

Figure I represents one form of an apparatus for carrying out the invention, in which the petroleum oil product to be treated is first commingled with the water solution of a metallic salt and thereafter heated to a reaction temperature, by causing the same to pass through a heating coil under pressure.

Figure II represents another form of apparatus in which the petroleum oil product and the Water solution of a metallic salt are separately heated to a reaction temperature, and are thereafter commingled by means of a jet mixer.

In Figure I, 3 represents generally a tank for holding a supply of gasoline or other petroleum oil stock to be processed. Pipe I, controlled by valve 2, connects the'gasoline stock tank 3 near the top to a source of supply not shown.

Pipe 4, controlled by valve 5, connects gasoline stock tank 3 to the inlet side of pump 6. Pipe 4!}, controlled by valve 4 I, connects pipe 4 to a fractionating tower not shown. Pipe I connects pump 6 to jet mixer 8.

I3 represents generally a tank for holding a concentrated water solution of a metallic salt, such as zinc chloride, zinc bromide, zinc iodide, etc., or any of the other metal salts heretofore (enumerated. Pipe I4, controlled by valve I5, connects tank I3 near the top to a source of supply not shown. Pipe I I, controlled by valve I2, connects tank I3 near the bottom tothe inlet side of pump I0. Pipe 9 connects the discharge side of pump III to jet mixer 8. 1

' Pipe I6 connects jet mixer 8 to heater coil 38. Heater coil 38 is stationed in the furnace I I. Furnace II'is provided with a burner I8 which leads to a supply of fuel not shown. Pipe 39, controlled by pressure release valve I9, connects heator coil 38 to distillation tower 2B. Distillation tower 2D is provided with bubble trays 2 I. Pipe 22, controlled by valve 23, connects distillation tower 20 near the bottom to a source of water supply not shown. Pipe 25, controlled by valve 24, connects distillation'towerZlI at the bottom to tank 26. Pipe 28, controlled by valve 21, connects tank 26 to a'storage not shown.

Pipe 29 connects distillation tower 20 at the top to condenser coil 3I. Condenser coil 3! is stationed in condenser box 30, which is provided with a Water inlet pipe 32 and a water outlet pipe 31. Pipe 32 leads to a source of water supply not shown, and pipe 31 leads to a waste receiver not shown.

Pipe 33 connects condenser coil 3| to treated gasoline tank 34. Pipe 36, controlled by valve 35, connects the treated gasoline tank near the bottom to a storage not shown.

In Figure II, 3 represents generally a tank for holding a supply of gasoline or other petroleum oil stock to be processed. Pipe I, controlled by valve 2, connects the gasoline stock tank 3 near the top to a source of supply not shown. Pipe 4, controlled by valve 5, connects the gasoline stock tank 3 to the inlet side of pump 8. Pipe 40, controlled by valve 4|, connects pipe 4 to a fractionating tower not shown. Pipe I connects pump 6 to heater coil 38. Heater coil 38 is stationed in a furnace l'l. Furnace H is provided with a burner 3 which leads to a fuel supply not shown.

l3 represents generally a tank for holding a concentrated water solution of a metallic salt, such as zinc chloride, zinc bromide, zinc iodide, 'etc., or any of the other metallic salts heretofore enumerated. Pipe l4, controlled by valve l5, connects tank l3 near the top to a source of supply not shown. Pipe ll, controlled by valve l2, connects tank I3 near the bottom to the inlet side of pump l0. Pipe 9 connects the discharge side of pump ID to heater coil 44. Heater coil 44 is stationed in furnace 42. Furnace 42 is provided with a burner 43 which leads to a fuel supply not shown.

Pipe 45 connects heater coil 44 to jet mixer 8. Pipe 39 connects heater coil 38 to jet mixer 8. Pipe I6 connects jet mixer 8 to reaction chamber 46.

Pipe 4?, controlled by pressure release valve l9, connects reaction chamber 46 to distillation tower 20. Distillation tower 20 is provided with bubble trays 2|. Pipe 22, controlled by valve 23, connects distillation tower 20 to a source of water supply not shown. Pipe 25, controlled by valve 24, connects the bottom of distillation tower 20 to tank 26. Pipe 28, controlled by valve 21, connects tank 26 to a storage not shown.

Pipe 29 connects distillation tower 20 at the top to condenser coil 3|. Condenser coil 3% is situated in condensed box 30, which is provided with a water inlet pipe 32 and a water outlet pipe 31. Pipe 32 leads to a source of water supply not shown, and pipe 31 leads to a waste receiver not shown. Pipe 33 connects condenser box 30 to treated gasoline tank 34. Pipe 36, controlled by valve 35, connects treated gasoline tank 34 near the bottom to a storage not shown.

The process as carried out in the apparatus described in Figure I is as follows:

Tank 3 is filled with the petroleum oil product to be treated by operation of valve 2. Petroleum oil distillate, such as gasoline stock, contained in tank 3, is permitted to flow through pipe 4 and into the inlet side of pump 6, the rate of flow being governed by operation of valve 5. Pump 6 continuously discharges the gasoline stock, under a pressure of approximately 100 to 1000 pounds gauge, into jet mixer 8, wherein the gasoline stock is continuously commingled with the necessary quantity of a substantially concentrated water solution of a metallic salt such as copper chloride from the supply tank l3.

The water solution of metallic salt contained in supply tank I3 is permitted to flow through pipe I I and into the inlet side of pump H), which discharges the same under a pressure ranging from approximately 100 to 1000 pounds gauge through pipe 9 and into said jet mixer 8, the rate of flow being governed by operation of valve l2.

The quantity of water solution of metallic salt may range from as low as 1 per cent to as high as 10 per cent or higher, by volume, depending upon the stock to be treated. For example, if a crude gasoline stock contains a high percentage of impurities to be extracted, as high as 10 per cent by volume or more of a concentrated water solution of any of the aforesaid metallic salts or mixtures of the same may be employed. The pressure maintained on the system by means of pumps 6 and I0 is so regulated that the commingled mixture of the water solution of metallic salt or salts and gasoline stock under treatment, passing through coil 38, will be maintained in a substantially liquid phase, such pressure depending upon the boiling point of the gasoline stock and the temperature employed.

From jet mixer 8, the gasoline stock, commingled with the water solution of the metallic salt or salts, passes through heater coil 38, pipe 39 and pressure release valve H), where the pressure is reduced to atmospheric or approximately atmospheric, and then passes into distillation tower 23. The commingled mixture passing through heater coil 38 is heated to the reaction temperature. Preferably, a temperature ranging from approximately 300 to 400 degrees F. is suitable to employ in treating ordinary gasoline stocks. However, with some grades of petroleum oil distillates, as high as 600 degrees F. or a little higher may be employed.

In distillation tower 20, the purified gasoline stock, at a temperature ranging from approximately 300 to 400 degrees F., together with a portion of the water content of the salt solution, are vaporized and separated from the products of the reaction and the metallic salt or salts employed. The purified gasoline stock, mixed with water vapor, passes out of distillation tower 20, through pipe 29, into condenser coil 3!, stationed in condenser box 30, wherein the said purified gasoline stock and water vapor are condensed to a liquid, passing through pipe 33 and into the treated gasoline tank 34. A cooling fluid such as water is employed to condense the gasoline vapors passing through condenser coil 3|, coming from a source not shown through pipe 32 and passing out of condenser box 30 through pipe 31. From the treated gasoline tank 34 the purified gasoline stock may be conducted to a storage not shown through pipe 3%, controlled by valve 35. The purified gasoline stock so obtained may be thereafter treated, if necessary, by other methods known in the art, or may be subjected to a distillation operation to separate fractions having any desired range of boiling points.

The metallic salts and products of reaction which separate in the bottom of distillation tower 20 are intermittently or continuously drawn into tank 26 through pipe 25, the flow being controlled by valve 24, water being continuously or intermittently introduced into the. lower section of distillation tower 20 through pipe 22, controlled by valve 23, in quantities sufficient to replace the vaporized water from the metallic salt water solution, so as to maintain the used metallic salts or compounds and prodnets of reaction in a fluid condition.

From tank 26 the excess water solution of metallic salt or salts and products of reaction are conducted to a storage not shown through pipe 28, controlled by valve 21, and the metallic salts or compounds are separated from the reaction products and purified for reuse.

Asillustrated in Figures I and II, if is desired to treat a gasoline stock coming directly from a fractionating tower or other distillation apparatus, in a vapor or semi-vapor state, valve 5 is closed and valve 4! is opened, which permits the gasoline stock coming from a source not shown, in a vapor or semi-vapor state, to flow through pipe 40 and into the inlet side of pump 6, wherein the gasoline stock is completely condensed to a liquid by the applied pressure maintained on the system and the introduction of the cool water solution of a metallic salt or salts in Figure I, and by the application of pressure in Figure. II.

The process as carried out in the apparatus described in Figure II is substantially the same as the process heretofore describedfor Figure I, except that the petroleum oil or gasoline stock to be treated and the water solution of a metallic salt or salts are first separately heated to the reaction temperature by heating coils 38 and 44, at a pressure sufficient to prevent any substantial vaporization therein, after which the heated gasoline stock and heated water solution of a metallic salt or salts, as heretofore enumerated, are commingled in jet mixer 8 and pass through pipe i6, reaction chamber 46, pipe 41, pressure release valve l9, and into distillation tower 20.

While the process 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 invention, such for example, as the use of centrifugal or other mechanical mixers, or the employment of any of the well known contact towers wherein a water solution of a metallic salt or mixtures of metallic salts, either organic or inorganic, heretofore enumerated, may be commingled with or brought into contact with a petroleum oil at a pressure sufficient to prevent substantial vaporization at the reacting temperature, and the invention includes all such modifications and changes as come within the scope of the appended claims.

I claim: a I

l. A process of purifying a petroleum oil product which comprises, causing the said product to vaporize from a heated commingled mixture of the product and a maintained water solution of a copper salt at a reaction temperature.

2. A process of purifying a petroleum oil product which comprises, heating and commingling said product with a water solution of a copper salt, under pressure sufiicient to prevent substantial vaporization, thereafter releasing the pressure and causing the product to vaporize from the heated commingled mixture at a reaction temperature while maintaining the copper salt in solution by the addition of water.

3. A process of purifying petroleum oil products, comprising, commingling a petroleum oil product with a substantially concentrated water solution of a copper salt, passing the commingled mixture through a heating coil and heating the mixture to a reaction temperature, under pressure sufiicient to prevent substantial vaporization, releasing the pressure and separating by vaporization, fractionation and condensation a purified petroleum oil product from products of reaction and excess treating agent.

4. A process of purifying petroleum oil, comprising, commingling the petroleum oil with a substantially concentrated water solution of copper salt, passing the commingled mixture through a heating coil and heating the mixture to a temperature of approximately 300-600 F., under pressure sufficient to prevent substantial vaporization, releasing the pressure and separating by vaporization, fractionation and condensation a purified petroleum oil product from products of reaction and excess treating agent.

5. A continuous process for purifying gasoline stocks, comprising, continuously commingling gasoline stock with a substantially concentrated water solution of a copper salt, continuously passing the commingled mixture through a heating element and heating the mixture to a temperature of approximately 300600 F., under pressure sufiicient to prevent substantial vaporization, releasing the pressure and separating by vaporization, fractionation and condensation a purified gasoline stock from products of reaction and excess treating agent.

6. A process of removing gum forming constituentsfrom cracked gasoline stock, comprising, commingling cracked gasoline stock with a water-solution of copper salt, and heating the commingled mixture to a temperature of approximately 300-600 F., under a pressure sufficient to prevent substantial vaporization, while passing through a heating zone, for a period of time sufficient to cause the unstable hydrocarbons contained in the cracked gasoline stock to poly-' merize vwith'the formation of gums, then reducing the pressure to approximately atmospheric, and separating by vaporization, fractionation and condensation a purified gasoline stock from products of reaction and polymerization, and excess treating agent.

'7. A continuous process for purifying gasoline or naphtha derived by thermo decomposition of higher boiling petroleum oils, comprising, continuously commingling the gasoline or naphtha with a water solution of copper chloride, continuously passing the commingled mixture through a heating zone and heating the commingled gasoline or naphtha and water solution of copper chloride to a temperature of approximately 300- 600 F., under a pressure sufficient to prevent substantial vaporization, continuously releasing the pressure after the commingled mixture of gasoline or naphtha and water solution of copper chloride has passed through said heating zone, continuously passing the treated gasoline or naphtha, products of reaction and excess treating agent into a vaporizing zone, continuously vaporizing, fractionating and separating a purified gasolineor naphtha and water vapor from higher boiling reaction products and excess treating agent.

8. A continuous process of purifying gasoline or naphtha derived by the thermo-molecular decomposition of higher boiling mineral oils, comprising, continuously commingling the gasoline or naphtha with a water solution of copper salt, continuously passing the commingled mixture through a heating zone and heating the commingled gasoline or naphtha and water solution of copper salt to a temperature of approximately 300-600 F., under a pressure sufficient to prevent substantial vaporization, continuously releasing the pressure and continuously passing the heated mixture of gasoline or naphtha, water solution of copper salt and products of reaction intoa vaporizing zone, continuously vaporizing and separating by fractionation and condensation a purified gasoline or naphtha mixed with water from higher boiling products of reaction and excess treating agent, continuously introducing water into the vaporizing zone inquantities sufficient to replace the water of vaporization, continuously withdrawing products of reaction and introducing water containing excess treating agent, substantially as described.

9. A process of purifying gasoline or naphtha, comprisingfcontacting the gasoline or naphtha with a water-solution of copper salt while passing through a heating zone, under a pressure sufficient to prevent substantial vaporization, and heating the mixed gasoline or naphtha and water heating the commingled mixture to a reaction temperature, under a presure sufiicient to prevent substantial vaporization, releasing the pressure and passing the treated petroleum oil, products of reaction and water solution of copper salt into a vaporizing zone, maintaining the copper salt in a fluid condition by the addition of water, vaporizing, fractionating and separating a purified petroleum oil mixed with water vapor from higher boiling reaction products and excess treat- 10 mg agent.

ARTHUR LACHMAN.

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