US2035608A - Process of purifying and refining hydrocarbon oils - Google Patents

Description

March 3l,

1936. A LACHMAN 2,035,608

PROCESS-OF' PURIFYING AND REFINING HYDROCARBON OILS original Filed Julye, 1929 -2 sheets-sheet l ATTORN EY March 3l, 1936. A, LACHMAN l 2,035,608 PROCESS 0F PURIFYING AND REFINING HYDROCARBON olLs A original Filed July 26, 1929 2 sheets-sheet? NN L WN. n .QN mlm: U 001%@ wmm im: N\.N .NWN

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ATTORNEY Patented Mar. 3l, 1936 PROCESS OF PURFYING AND REFINING HYDRCAREN GILS Arthur Lachman, Berkeley, Calif., assignor to Vapor Treating Processes, Inc., Los Angeles, Calif., a corporation of California 7 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,

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 bearing mineral oils, in Which hydrogen sulphide, mercaptans and other sulphur bearing compounds, as Well as varying percentages or" oxygenated hydrocarbons and unstable hydrocarbons (such as diolenes 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, led July 26, 1929, for Process of purifying and rening hydrocarbon oils.

Reference is made to United States Patent No. 1,809,170, granted June 9, 1931 to Arthur Lachman, Serial No. 361,513, led May 8, 1929, for Process of refining hydrocarbon oils, which discloses a vapor phase method or process for purifying and rening mineral oil products With a Water solution of certain metallic salts, or mixtures of thesame, 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 undened nature. These latter substances are readily oxidizable at ordinary temperature and are usually responsible for the change of acid depending upon the nature of the gasoline stock to be treated and the degree of renement 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 Well-known 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 oi 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 noncorrosive 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 corrosive compounds during a subsequent distillation.

The general objections to a treatment of this` character are as follow: (l) 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 diiicult to recover; (3) as high as 10 per cent 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 sulp-huric acid normally used to treat crude gasoline stocks may be reduced to a great extent, and in manyl 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 Withy a substantially concentrated water solution o 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 showninv Figure II, the gasoline stock and water solution of rnetallic salt or salts may be rst separately heated and then commingled under a pressure.

'I'he 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 rst partly purified by my invention and the purication 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, ranging from 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 oi less concentration may be employed, which may range from 50 or less Vto approximately 85 per cent, the strength of the water solution of the metallic salt or mixtures of salts employed is preferably a substantially concentrated solution, and the temperature employed for the treatment is preferably approximately 300 to 600 degrees F., this temperature depending upon the vaporizing temperature of the oil under treatment.

One of the principal objects of this invention is to accomplish a purification of gasoline or naphtha stocks produced by thermo molecular decomposition of high boiling petroleum oils, by a treatment with a substantially concentrated water solution of a metal salt, under a pressure sulcient to prevent any substantial vaporization thereof, and at a temperature of approximately 300 to 600 degrees followed by a distillation and fractionation operation to separate the products of reaction and higher boiling polymerlzed 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 superatmospheric 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, economica-1 method for improving 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 rst 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 cil 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 4U, controlled by valve 4I, connects pipe 4 to a fractionating tower not shown. Pipe 'I connects pump E 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 I`3 near the top to a source of supply not shown. Pipe II, controlled by valve I2, connects tank I3 near the bottom to the inlet side of pump I8. Pipe 9 connects the discharge side of pump I0 to jet mixer 8.

Pipe I6 connects jet mixer 8 to heater coil 38. Heater coil 38 is stationed in the furnace I'I. Furnace I'I is provided with a burner I8 which leads to a supply of fuel not shown. Pipe 39, controlled by pressure release valve I9, connects heater coil 38 to distillation tower 2c. Distillation tower 28 is provided with bubble trays 2|. Pipe 22, controlled by valve 23, connects distillation tower 2i] near the bottom to a source of Water supply not shown. Pipe 25, controlled by valve 24, connects distillation tower 20 at the bottom to tank 26. Pipe 28, controlled by valve 21, con-V nects tank 26 to a storage not shown.l

Pipe 29 connects distillation tower 2B at the top to condenser coil 3|. Condensercoil 3l is stationed in condenser box 30, which is provided with a Water inlet pipe 32 anda 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 3 3 connects condenser coil 3| to treated gasoline tank 34. Pipe 36, controlledby 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 Vtop to a source of supply not shown. Pipe 4,

controlled by valve 5, connects the gasoline stockV tank 3 to the inlet side of pump 6. Pipe 40, controlled by valve 4I, connects pipe 4 to a fractionating tower not shown. Pipe 1 connects pump 6 toY heater coil 38. Heater coil 38 is stationed in a. furnace I1. Furnace I1 is provided with a burner I 8 which leads to a fuel supply not shown.

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 metallic salts heretofore enumerated. Pipe I2, controlled by valve I5, connects tank I3 near the top to a source of supply not shown. Pipe II, controlled by valve I2, connects tank I3 near the bottom to the inlet side of pump Iii. Pipe 9 connects the discharge side of pump I0 to heater coil 44. Heater coil 44 is stationed in furnace 42. Furnace 42 is provided with a burner i3 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 I6Yconnects jet mixer 8 to reaction chamber 46.

Pipe 41, controlled by pressure release valve I9, connects reaction chamber i5 to distillation tower 20. Distillation tower 2S is provided with bubble trays 2l. 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 25. 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 3l is situated 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 box 35 to treated gasoline tank 3:3. Pipe 35, controlled by Valve 35, connects treated gasoline tank 3ft 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 lled 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 new through pipe and into the inlet side of pump 5, 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 zinc chloride from the supply tank I3.

The water solution of metallic salt contained in supply tank i3 is permitted to flow through pipe II and into the inlet side of pump I0, 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 I2.

The quantity of water solution of metallic salt may range from as low as l 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 irnpurities to be extracted, as high as l0 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 emplo-yed.

From jet mixer 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 I9, Where the pressure is reduced to atmospheric or approximately atmospheric, and then passes into distillation tower 20. The commingled mixture passing through heater coil 3S 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 puried gasoline stock, mixed with water Vapor, passes out of distillation tower 20, through pipe 29, into condenser coil 3l, stationed in condenser box 30, wherein the said puried 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 BI, coming from a source not shown through pipe 32 and passing out of condenser box 30 through pipe 31. From the treated gasoline tank 36 the purified gasoline stock may be conducted to a storage not shown through pipe 36, controlled by Valve 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 2li, Water being continuously or intermittently introduced into the lower section of distillation tower 20 through pipe 22, controlled by valve 23, in quantities suflicient to replace the vaporized water from the metallic salt water solution, so as to maintain the used metallic salts or compounds and products 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 re-use.

As illustrated in Figures I and II, if it 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 4I is opened, which permits the gasoline stock coming from a source not shown, in a vapor or semi-vapor state, to iiow through pipe 40 and into the inlet side of pump E, 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 CTI described in Figure II is substantially the same as the process heretofore described for 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 33 and llil, at a pressure suiiicient 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 B and pass through pipe i6, reaction chamber 35, pipe pressure release valve I9, and into distillation tower 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 suicient to prevent substantial vaporization at the reacting temperature, and the invention includes all such modications and changes as come within the scope of the appended claims.

I claim:

l. The process of purifying petroleum oil products comprising heating a petroleum oil product to a temperature of approximately 300 to 600 F. separately heating a substantially concentrated Water solution of zinc sulphate and forcing it into said heated oil product, subsequently forcing the mixture through a pressure maintaining Valve into a fractionating tower and removing the surplus Water together with the products of reaction from the oil.

2. A process oi removing gum-forming constituents from cracked gasoline stock, comprising, heating a cracked gasoline stock and separately heating a water solution of zinc salt to a temperature of approximately 300 to 600 degrees F., and commingling the same under a pressure suicient to prevent any substantial vaporization, for a period of time sufficient to cause unstable hydrocarbons contained in the cracked gasoline stock to polymerize with the formation of gums, then reducing the pressure to approximately atmospheric, and separating by vaporization, fractionation and condensation a purified gasoline stock from the water and products of reaction.

3. A process of purifying petroleum oil products, comprising; commingling a heated petroleum oil product with a heated, substantially concentrated, water solution of a zinc salt, at a reaction temperature, under pressure sucient to prevent substantial vaporization, releasing the pressure and separating by vaporization, fractionation and condensation a puried petroleum oil product from products of reaction and excess treating agent.

4. A continuous process for purifying gasoline stocks, comprising, continuously commingling heated gasoline stock with a heated, substantially concentrated, water solution of a zinc salt, at temperatures of approximately 30G-600 F., under pressure sunicient 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.

5. A process of purifying gasoline stock, comprising, contacting heated gasoline stock With a heated Water solution of a zinc salt in a mixer, at temperatures of approximately 3D0-600 F., under a pressure sufficient 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 constituents from cracked gasoline stock, comprising, contacting heated cracked gasoline stock with a heated Water solution of a zinc salt, at temperatures or" approximately 30G-600 F., under a pressure suicient to prevent substantial vaporization, for a period of time sufcient to cause unstable hydrocarbons contained in the gasolinestock to polymerize with the formation of gums, rel-easing the pressure and separating by Vaporization, fractionation and condensation a purified gasoline stock from products of polymerization and excess treating agent.

7. A process of purifying petroleum oil, comprising, commingling a heated petroleum oil with a heated Water solution of zinc salt at a reaction temperature, under pressure sufficient to prevent substantial Vaporization, releasing the pressure and passing the treated petroleum oil, products of reaction and Water solution of Zinc salt into a vaporizing Zone, maintaining the concentration of the Water solution of zinc salt in the vaporiz- F ing zone by addition of Water, and vaporizing, fractionating and separating puried petroleum oil from higher boiling products and excess treating agent.

ARTHUR LACHMAN.

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