US1983220A

US1983220A - Method of refining petroleum oil distillates

Info

Publication number: US1983220A
Application number: US661471A
Authority: US
Inventors: John D Fields
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-03-18
Filing date: 1933-03-18
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

Dec. 4, 1934. J, D. FIELDS 1,983,220

METHOD OF REFINING PETROLEUM OIL DISTILLATES Filed March 18, 1935 HIIIIIIIIIIIHHII Patented Dec. 4, 1934 PATENT OFFICE METHOD F BEFINING PETROLEUM OIL DISTILLATES John D. Fields, Los Angeles, Calif.

Application March 18,

9 Claims.

My invention relates to a method of refining distillates and more particularly pertains to a process for treating petroleum distillates to remove certain impurities therefrom in which a catalytic action of an alkali metal is employed in a manner similar to and for the purposes set forth in United States Letters Patent Number 1,864,719, issued to me `under date of June 28, 1932, for Method of refining distillates.

An object of the invention is to provide a method of the above character whereby the purification of distillates to effect the production of a sweet smelling, water white, stable product of great brilliancy. may be obtained by removing undesirable substances or compounds contained in the distillate which impart to it objectionable odors and discoloration, and which render it unstable, through the medium of an alkali metal catalyst, in which the treatment of the distillates may be effected in a closed tank with either a continuous or intermittent operation, without the use ofmechanical agitators, pumps or like instrumentalities, and whereby the purifying treatment may beeffected at atmospheric temperatures and pressures and in such manner as to accomplish the refining and purification of the distillates at greatly'` reduced cost over processes now generally in use. i Another object is to provide a method of purifying distillates with the aid of alkali metal catalyzers in which the impurities will separate from the liquid under treatment in a tank in such man1,

ner that the impurities may be readilyyremoved from the rened product, and inwhich the impurities are rendered of such characterastohave;

commercialvalue. l

Another object is to provide a process of the above character in which the purification action may be rapidlyeected and without appreciable loss of light gasoline vapors and withoutloss of the octane number 'or other aromatics and thus avoid raising the boiling point of the resultant gasoline. A

Another object is. to provide a distillate refining method in which the distillates are acted on by an alkali metal. catalyzer in such `manner, as

to effect coagulation and precipitation of gums in the liquid under treatment, and in which dissolving of such coagulatedv substances heldin suspensicn in 'the'llquidl together with the gums that have beenjprecipitated on the alkali metal catalyzers will .be effected to form a heavy oil which may be readily drawn on lfrom the liquid under treatment. f V Another object is to provide a processwhich is 1933, Serial No. 661,471

(Cl. ISIS- 23) applicable for use in the purifying of pressure distillates either before or subsequent to treatment by theusual acid process, or independent thereof, and which where employed subsequent to the acid treatment the use of sodium plumbite will be obviated. i

A further object is to provide a distillate refining process employing an alkali metal catalyst in which the amount of consumption of alkali metal required for treatment of a particular quality of distillate may be accurately predetermined.

'I'he invention and the mode of accomplishing the objects and advantages above set forth, together with such other objects and advantages as may subsequently appear, further resides in the steps and features hereinafter more fully described and claimed and illustrated by way of example in the accompanying drawing in which the figure is a diagrammatic view of a distillate refining apparatus and depicting the manner of carrying the invention into effect.

The apparatus as shown in the drawing ernbodies a tank 2 for containing the distillates during treatment and which tank for the purpose of facilitating a substantially uniform action throughout the liquid body therein is formed with adownwardly converging or conical shaped bottom portion 3 from the lower end of which leads a discharge pipe 4 fitted with a cut-off valve 5.

The upper end of the tank 2 is provided with an opening 6 fitted with a cover 7 and which opening iisfprovided forfthe purpose of giving access to fthe interior of the tank'auditorleriablingfithe*inf` sertion into the tank yan'dfrernoval"tl'ierefrciin-of` .atcagevdzcarrying-catalytic bodies 9 which bodies mare'formed of solid alkali metal such as sodium, potassium, or lithium. The cage 8 may be of any suitable construction, being here shown as formed of wire netting but manifestly may be of any suitable open formation to permit circulation of liquid therethrough. One end of the cage is fitted with a removable cover 10. A rack 12 is provided at a suitable point within the tank for affording a support for the cage 8. I

In some instances cage 8 may be dispensed with and the alkali metal bodies placed loose in the tank 2.

The distillates to be treated are delivered to the tank from any suitable source of supply through a conduit 14 fitted with a valve 15 which conduit leads into the upper portion of the tank. As a means for conveying gases from the tank so as to prevent development of excessive pressures therein, the upper end of the tank is fitted with a vent pipe 16 equipped with a cut-oi! valve 17.

An important feature of the present invention resides in delivering to the distillate content of the tank a halogen salt in solution, and for this purpose a reservoris provided for such solution, as indicated at 18, from which leads a conduit 19 communicating with the upper end of the tank through a regulating valve 20. The reservoir 18 is tted with a suitable measuring gage 21 to enable drawing off of a predetermined volume of the solution from the reservoir 18.

The tank 2 is equipped with a gage glass 22 for indicating the level of the distillates within the tank, and is also iltted with a gage glass 23 for indicating the level of a heavy oil embodying separated impurities which accumulate in the lower portion of the tank.

While the present method is applicable to the treatment of petroleum distillates of various fractions or combinations thereof, it is especially applicable to the treatment of distillates of low boiling point, that is distillates which pass off at temperatures up to approximately 500 degrees Fahrenheit, and may be distillates derived from heavy petroleum oils by cracking. In fact the method is designed to be employed in the treatment of any hydrocarbons containing impurities which are subject to being removed as herein set forth by the action of alkali metal catalyzers.

As an example of impurities that are subject to being removed by this process are those of resinous and gummy character and include the olen hydrocarbons embracing mono-oleilns, the di-olefins or poly-olens, and the acetylene isomers of di-olefins; naphthenes; sulfur compounds; nitrogen bases and acid compounds.

Without binding myself toany particular theory of operation it seems proper to state that the impurities removed or to be removed are such that cold solid alkali metal may act as a catalyst to produce a condensing reaction to form products which are soluble in a menstruum embodying halogen salts, these products being usually oi a gummy or resinous or rubbery nature which coagulate, and which undoubtedly include certain sulfur compounds and which when present in distillates impart an objectionable odor and discoloration thereto and which render the distillates unstable and also result in the formation of gums or resinous deposits on utilizing the refined product as in combusting it in motors.

The alkali metal catalyst is employed in the form of solid bodies which are so shaped that they may be arranged within the cage 8 in a manner to afford interstices through which the distillates may ow and in such manner as to cause the flowing distillates to be deected into numerous small streams between adjacent catalytic bodies, and whereby the distillates will be brought into superficial contact with or in close proximity to a considerable area of the surface o1' the catalytic bodies. For this purpose the catalyzers may be shaped'in the form of spheres, blocks or bars. They are placed within the cage 8 through the opening in the upper end thereof, and the cage is placed within the tank through the opening 6 as before described. The catalyzer bodies are preferably thus confined in a cage to prevent their floating to the top of the liquid under treatment and also to facilitate the removal and replacement of the catalyzers as occasion requires.

The halogen salt solution, which as before stated includes solutions of magnesium chloride, ferrous chloride, zinc chloride, and hydrous aluminum chloride, is prepared in the yproportion of approxlmatehr one gram of the halogen salt to one liter of water, but w h proportion is subject to variations, the propo ons being such that the solution will act as a solvent in cleaning the (resinous and other gummy) impurities from the alkali metal and also to dissolve the coagulated substances held in suspension in the distillates. In other words, the solution may comprise approximately one part in 100 of halogen salts to 99 parts of water by weight, thus forming a one per cent solution, but a stronger or weaker solution may be used. I

The halogen salt solution may be employed in the proportion of approximately 10 c. c. of the solution to four liters of the distillates, which is equivalent to approximately 10 gallons of solution to one hundred barrels of distillate, but the proportions may be varied since an excess of salt solution is not detrimental.

In carrying the method into effect a quantity of the alkali metalcatalyzers is placed within the tank, as in the cage 8; which quantity is proportioned to the volume o`f distillates to be treated, and according to the proportions of impurities contained in the distillates to be treated, for example if tests show that the distillates to be treated carry approximately 250 millograms of gum per 100 c. c. of distillates. then approximately two and one-half ounces of alkali metal will be employed for each forty-two gallon barrel of distillates to be treated. In other words, assuming the tank to be of 100 barrel capacity, then the quantity of alkali metal used will be approximately 250. ounces. It will be understood, however, that the proportions may be varied as occasion requires. Manifestly an excess of the alkali metal in proportion to the volume of distillate under treatment will not be detrimental.

A predetermined volume of distillates to be treated is then delivered to the tank and coniined therein; the valves 5 and 15 then being closed. A precipitation of heavy gums immediately commences due to the catalytic action of the alkali metal; which eects condensation of such impurities into a flocculent form. The ilocculent impurities whose coagulation has thus been effected by the action of the catalyzers collect in part on the catalyzer bodies, and a portion of such impurities are suspended in the distillates. This action of the alkali metal is immediate and on such action having occurred a measured volume of the halogen salt solution in the proportion above stated is delivered to the tank, as by opening the valve 20, which solution on flowing into the distillates within the tank sinks therein and comes in contact with the alkali metal thereby immediately effecting the evolution of hydrogen gas and thus causing violent agitation of the liquid in the tank.

This agitation serves to cause all of the liquid in the tank to be brought into intimate contact or close association with the alkali metal and thereby causing the latter to effect formation of the ilocculated or coagulated impurities throughout the liquid under treatment and also causing the salt solution to act on such impurities as are held in suspension in the distillates and also deposited on the alkali metal catalyzers; the salt solution acting as a solvent to convert the coagulated substances (resins and gums) into a heavy reddish oil which settles to the bottom of the tank from whence the oil may be drawn off as by opening the valve 5 from time to time as occasion may require or on completion of the treatment of the acid process.

Lacasse d The process above described is carried out at normal atmospheric temperatures or at the ordinary temperatures of the liquid distillates, and does not require the generation and application of extraneous heat. The process is also carried on at normal atmospheric pressures; the evolved gases which may accumulate in the tank and thereby create pressures therein being drawn oil as occasion requires through the vent pipe 16.

By this process no mechanical agitation of the liquid is necessary since the agitation set up from the formation of hydrogen gas eiects the requisite contact of the distillates with the alkali metal and also the intermixture of the salt solution and the distillates, within a short period. It has been found in practice that approximately 10 minutes is required to eiect treatment of a batch of distillates in the manner above set forth where the proper proportions of distillate, alkali metal and salt solution are employed.

The resultant red oil which contains the removeddmpurities in solution constitutes a saturated solution of sodium hydroxide which is readily separable from the distillates and is a product of commercial value.

The resultant distillates will be practically free of objectionable gum and sulfur compounds and is t for use for commercial purposes, and if redistilled the majority of distillates will be water white and will be stable when exposed to sun light.

However there are instanceswhere because of the nature and quantity of resinous, gummy and sulfur compound impurities contained in some distillates, it is found desirable to employ the present process in conjunction with the sulfuric acid process either preliminary or subsequent thereto, in which instance it is found that a much lesser quantity of sulfuric acid is required for carrying out the. acid treatment than where such acid treatment is employed alone, and also that it is unnecessary to employ the usual doctor treatment with sodium plumbite as ordinarily used in to be employed together with the acid process the distillates are treated with a solution of one to three lbs. of Baume sulfuric acid per barrel of distillates under treatment. As before stated this acid treatment may be effected either before or after treatment by the present process.

The process is highly economical since it has been found in vpractice that in the treatment of a cracked or pressure distillate containing apbarrel.

While I have shown and described a particular apparatus for carrying the invention into effect, various other structures may be employed. In

i fact the invention may be practiced by means of the ordinary distillate storage tanks, and without the provision of any special equipment. Furthermore while the mode of operation has been described as intermittent, that is to say, as applied to the treatment of a batch of distillates in a tank which after being treated is drawn from the tank and the latter recharged, it is manifest that the method may be carried out by a continuous operation, as by maintaining a ilow of distillates and salt solution in proper proportions over a mass of alkali metal catalyzers.

I claim:

1. The method of removing impurities from petroleum distillates, consisting in subjecting a Where the present process is relatively large volume of such' distillates in liquid condition to the catalytic action of a relatively small mass of solid bodies of an alkali metal in the cold, for a sufficient period of time to effect coagulation of the bulk of the impurities, whereby some of the impurities become precipi tated on the alkali metal and some is held in suspension in the distillates in a ilocculent state, then adding to the distillates a relatively small quantity of a solution of halogen salts whereby the coagulated impurities will be dissolved and converted into a heavy oil and separating said oil from the distillates.

2. The methodV of removing from petroleum distillates impurities contained in solution therein. consisting in maintaining a relatively small mass of solid bodies of alkali metal and a relatively'large volume of the distillates in intimate juxtaposition while at about normal atmospheric temperature, for such length of time as to effeet coagulation of at least a major portion of the impurities in the distillates treated, then adding to the distillates a small volume of a solution of mineral salts capable of dissolving the coagulated impurities and to convert same into a heavy oil and separating said oil from the distillates.

3. A process which comprises placing a relatively small mass of solid alkali metal within a large bulk of petroleum oil distillates, to cause coagulation of certain substances in said distillates, introducing into the distillates and into contact with said alkali metals a small volume of a solution of halogen salts to eiect evolution of hydrogen gas and resultant agitation of the distillates and to cause said solution to dissolve the coagulates into a heavy oil, and separating said oil from the distillates.

4. A process which comprises placing a relatively small mass of solid alkali metal within a relatively large bulk of petroleum oil distillates and maintaining said metal within thedistillates until coagulation of substances in the distillates takes place, then contacting the alkali metal while in the distillates with a small volume of a halogen salt solution to effect evolution of hydrogen gas, and supplying such volume of said salt solution to the distillates as to eilect conversion of the coagulates into oil, and removing the oil and formed gases.

5. A process which comprises placing a relatively small mass of solid alkali metal within a relatively large bulk of petroleum oil distillates and maintaining said metal within the distillates until coagulation of substances in the distillates takes place, then contacting the alkali metal while in the distillates with a small volume of a halogen salt solution lto eifect evolution of hydrogen gas, and supplying such volume of said salt solution to the distillates as to effect conversion of the coagulates into oil, removing the oil and formed gases, subjecting the remaining distillates to the action cf sulfuric acid, and nally washing and redistilling the distillate product.

6. The process of refining petroleum oil distillates which consists in placing Within a relatively large bulk of distillates a relatively small mass of solid alkali metal. adding to the distillates a small volume of a halogen salt solution of about one per cent strength in such manner as to bring said solution and alkali metal into contact, employing said solution in such proportions as to effect diolution of at least a portion of said alkali metal and to effect dissolving of coagulates formed in the distlllates by the catalytic action of the alkali metal.

7. In a process for rening petroleum oil distillates, the step which consists in adding a small volume of a solution of halogen salts to a large bulk of distillates containing a relatively small amount of solid alkali metal.

8. The process of refining petroleum oil distillates to effect removal of resinous and gummy constituents thereof consisting in subjecting the distillates to the combined action of a solid alkali metal and a solution of halogen salts :in substantially the proportions of ten gallons of the salt solution and two hundred and fifty ounces of alkali metal to one hundred barrels of distillates.

peratures and pressures.

. JOHN D. FIELDS.