US2342042A - Method of refining liquids - Google Patents

Description

Feb. 15, 1944. R, H* FA'SH y 2,342,042

METHOD OF REFINING LIQUIDS Filed Feb. 27, 1942 4 Sheets-Sheet l Feb. 15, 3.944 R. H FASH METHOD OF REFINING LIQUIDS Filed Feb. 27, 1942 4 Sheets-Sheet 2 Feb. 15, 1944. R Hl 'FAS-H 2,342,642

METHOD OF REFINING LIQUIDS Filed Feb. 27, 1942 4 Sheets-Sheet 5 un mlmin Le 4 i,

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- nur Patented Feb. 15, 1944 UNITED. STATES PATENT OFFICE METHOD F REFINING LIQUIDS Ralph H. Fash, Fort Worth, Tex., assigner, by ,mesne assignments, to Anderson, Clayton & Co.,

Houston, Tex., a corporation o! Delaware Application February 27, 1942, Serial No. 432,719

34 Claims. (Cl. 2611-425) The invention relates to the treatment of liquids, such as oils, and more particularly to the e refining of vegetable and animal oils which contain free fatty acids, vand/or which contain as impurities electrically charged colloidal particles. The invention also relates to method of re-refining these substances. A typical glyceride oil susceptible o f rening and re-renning in accordance with the invention is cottonseed oil, and, for the sake of brevity, the discussion herein will be limited to that type of oli, it being understood that this is without limitation as to substances susceptible of treatment in accordance with the invention.

In refining cottonseed oil, the present practice is to add an amount of caustic alkali which is considerably in excess of the amount required to neutralize thejree fatty acids in the oil being refined. The purpose `of adding this amount of caustic alkali is to neutralize the free fatty acids l present in the crude oli and to reduce the color of lthe oil.

The water, which is introduced with the caustic alkali, and the soap, which is formed by the reaction of the caustic alkali with the free fatty acids and with the neutral oil, form an emulsion with the oil. In order to separate the refined oil from the soap and water, which, together with other impurities, are known as soap stock, it is necessary first to break the emulsion. This is usually done by heating the emulsion to an emulsion-breaking temperature, and the soap stock may be then separated from the oil by the use of a centrifugal separator, or in any other suitable manner. The standard processes which are used in the vegetable oil refining industry may be divided into two broad classes, (1) the kettle process, and (2) the continuous process. which has largely superseded the kettle process, is .exemplified by the method disclosed in Patent No. 1,457,072, Hapgood et al., May 29, 1923.

Insofar as the process which is claimed herein is analogous to the prior art processes, it may be considered a continuous process. By the term continuous, as applied to the process, I mean that it is capable of continuous operation in the sense that crude oil is continuously supplied to the refining apparatus and refined oil is continuously delivered by the apparatus. I do not mean that any given portion necessarily is continuously passing through the refining apparatus at a constant rate, since, as will be explained hereinafter, the iiow of the oil and soap stock may be` retarded or stopped for certain purposes. In 'accordance with the lpresent invention, cottonseed oil may be rened by treatment with a neutralizing agent, such as caustic alkali, and the most striking difference between this process and previous processes is in the manner of mixing the The continuous process,

oil and refining agent. It will be pointed out hereinafter, however, that the dierence is a fundamental one.

The principal advantage of the present invention in the treatment of cottonseed oil lies in a very much lower refining loss and a cleaner refined oil.

The reduction in refining loss results from the fact that the process makes possible the use of an amount of caustic alkali which is only slightly in excess of that which is theoretically required to neutralize the free fatty acids in the oil which is being treated. I have found that the use of a considerable excess of caustic alkali, as in the previous processes, is not necessary in my process to obtain decolorization, and the slight excess which is used in my process is only used for the purpose of maintaining a low hydrogen ion conf` centration which is desirable for reasons which will be hereinafter explained.

As the result of' extensive investigation, I have concluded that the coloring matter in cottonseed oil is colloidal, and that it is held in colloidal suspension by positive electrical charges which exist on the individual colloidal particles. By bringing negatively charged particles into contact with these positively charged colloidal particles. the positive electrical charges are neutralized and the particles are thrown out of suspension.

I have also found that, in addition to the co1- loidal coloring matter, there are also present in the oil other positively charged colloidal particles which may be precipitated if their char-ges are neutralized by Vcontact with negatively charged particles. These colloidal particles include gums. phosphatides, and other lecithin-like bodies.

- Both types of positively charged colloidal particles or dispersoids exist in the oil in various degrees of dispersion, and, I have found that in a refining process which brings about the removal of `these colloidal dispersoids by neutralization of their electrical charges, it is necessary to use a negatively charged colloidal suspension, the dispersion of which is of approximately the sameorder as is the dispersion of the colloidal dispersoids which are to be removed. If only the largest of the dispersoids are to be removed, this can be accomplished by the use of relatively large oppositely charged particles, but, since, in the rening of cottonseed oil, a substantially complete removal of the coloring matter is usuallydesired, and this coloring matter -is for the most part highly dispersed, it is necessary to use negatively charged particles which are of extremely small size.

I have mentioned above the reduction in refining loss made possible by the use of only a slight excess of caustic over that theoretically required to neutralize the free fatty acids. This use of only a-,small vexcess of caustic maybe effected by various procedures. fIn all cases, it involves the disintegration ofthe oil and caustic solution, where'color removal is of paramount importance, and their mixing.v According to one preferred practice, the oil and caustic solution are sepaf rately formed into mists and then mixed. However, very good results, greatly superior to anything possible under procedures now in common use, are obtainable by merging the liquids, without mixing them to such an extent as would result in increasing the refining loss to that which would be obtained by the use of conventional rening procedures, and then forming them into a homogeneous mist mixture. The

preferred procedures involve` uniformity of distribution of the oil and caustic solution relative to each other, and rapid and uniform mixing.

1 y sion immediately to the centrifuge, but. if it is desired to agglomerate the soap stock somewhat to facilitate separation, the broken emulsion can .y be subjected to temporary retardation or arrest of flow. In re-reining, there is ordinarily a retarding or arresting step in order that the slightl excess ofl caustic Vwill be consumed to such a point that a single-layer soap stock results. Due to the very slight excess of caustic used in rerening, this consumption of the excess through.

saponication of neutral oil occasions no material loss of the latter.

In the processes now in common use, involving the decolorizing of cottonseed oil by the use of -caustic. alkali, an amount of caustic alkali greatly in excess of that theoretically required to neutralize the free fatty acids is used. 'I'he negative electrical charges on the soap formed by the reaction of the caustic alkali with the free fatty acids in the oil results in only a very slight decolorization, and this is due to the electrical neutralization of only the largestv of the positively charged colloidal suspensoids by the negative charges on soap thus formed. The soap formed from the free fatty acids agglomerates rapidly, thus limiting the use oi the electrical charges on the soap to the neutralization of the less highly dispersed vsuspensoids of the oil. By the use of a large excess of caustic alkali, it is possible, according to the said processes now in common use, to Vcbtain a'sufflciently complete removal of the coloring matter only if the caustic alkali and cil are maintained in contact for a sufficient period of time to bring about saponication of neutral oil -by'the excess of caustic. Even then it is necessary to maintain a low temperature (about 80 lJF.) to prevent rapid agglomeration of the soap y formed from the neutral oil.

Whereas the conventional mixing of caustic alkali solution and crude oil results in large particles of soap being formed by reaction with the free fatty acids, the reactionof the caustic alkali with the neutral oil results in the formation of highly dispersed colloidal soap. The highly 'dispersed negatively charged colloidal soap,l formed 'moval isv obtained. It has'never before been possible, however, to obtain satisfactory color removal without objectionably high due to this saponification of neutral oil.

By my process, it is possible to obtain a highly satisfactory degree of color removal vithout saponifying any substantial amount of neutral oil, and, consequently, without any substantial refining loss due to the saponiiication of neutral oil. My process may, therefore, be said to differ from the previously known processes in that the free fatty acids present in the crude oil are neuF tralized in` a manner which results in the formation of a highly dispersed colloida1 soap and in the immediate utilization ofI the electrical charges thereon to neutralize the charges on the highly dispersed suspensoids present in the oil, whereas in the previous processes, the highly dispersed colloidal soap. whose electrical charges can be utilized for the neutralization of charges on the highly dispersed suspensoids, is formed only by the saponication of neutral oil.

The essential characteristic of the method of forming highly dispersed colloidal soap from the free fatty acids is the mimng of the rening agent and the oil when both are in the form of mists or aerosols. By an aerosol, I mean a dispersion of minute particles which are of approximately colloidal dimensions, as in a mist or fog. I do not limit the term aerosol tol include only those systems which will remain in dispersion for along period of time, but. on the contrary, I use the term to describe the character of the dispersion at the time it is formed. Since the desired reactions take place in a fraction of a second, I am not concerned with the permanency aerosol. l

When aerosols of the oil and caustic solution are mixed, highly dispersed colloidal particles of soap are formed by reaction between the caustic alkali and the free fatty acids contained in the oil. At the same time, the highly dispersed colloidal soap is intimately mixed with the atomized neutral (i. e., as regards acid) oil. As a result, the negative charges on the highly dispersed colloidal soap are able to neutralize positive charges dispersed colloidal matter, and the latter is thereby thrown out of suspension.

In preferred practice, in accordance with the invention, the mixed aerosols are collected as an emulsion on a heated surface by .which an emulsion-breaking temperature is imparted to the emulsion, and thereafter separation of the soap stock from the oil may be effected by conventional means, for example a centrifugal separator.

When crude cottonseed oi1 is rened with a caustic alkali solution, the soap stock formed contains neutral oil, usually from 25% to 30% of the weight of the soap stock. Assuming a production of 20% soap stock, at least 5% of the reilning loss is due to neutral oil contained in the soap stock. Therefore, the reduction of the retention of neutral oil by the soap stock would materially reduce therening loss and make available for edible purposes oil which, under the common system of rening, now is only used as reilning losses or stability of the stock before all of the excess caustic soda is consumed and, as a result, this unconsumed caustic soda saponies some of the neutral oil in the soap stock after the separation of the soap stock from the oil. Therefore, the determination of the neutral oil content of the soap stock does not represent the neutral oil content of the soap stock at the instant of separation from the oil. Because of the continued action of the unconsumed caustic soda in the soap stock, a low neutral oil content is shown as present in the soap stock, producing a fictitious effect of etliciency of separation of neutral oil from the soap stock.

I have vdiscovered that the neutral oil contained in soap stock occurs in the soap stock in a dual emulsion, part as an oil-in-water emul sion and part as a water-in-oil emulsiomand as wetted oil, wetting electrically neutral colloidal particles precipitated from the oil. The neutral oil contained in the soap stock as an oil-in-water emulsion is stabilized by the sodium soap formed during the refining process and usually consti-y tutes the major portion of the neutral oil in the soap stock. The neutral oil contained in the soap stock as a water-in-oil emulsion is stabilizedby colloidal material, such as lecithin, originally contained in the oil being refined as an electrically charged colloidal suspension which, when electrically neutral, dissolves in the oil and sta` bilizes the water-in-'oil emulsion.

In this water-in-oil emulsion, the oil-in-water emulsion constitutes `the water phase. My discovery that neutral oil is contained in soap stock in a dual emulsion constitutes the basis on which the present aspect of the invention was developed.

In reiining as here contemplated, the speed of operation is so rapid that the .formation of a water-in-oil emulsion by solution of electrically neutral emulsifying material in the oil is practically prevented. However,`where a sodiumcontainingl neutralizing agent is used, the soap stock will contain the oil-in-water emulsion, since the chain-waterv emulsion is occasionedby the use oi a sodium-containing neutralizing agent, and, since there is present practically no waterin-oil emulsion, one procedure under the present invention is the` neutralization of the free fatty acids with a neutralizing agent which will form a water-insoluble soap 'rather' than a watersoluble soap, and, because of the rapidity of the process, the solution in the oll of the water-insoluble soap and/or the electrically neutral emul' sifying material precipitated 'from the oil, will be practically prevented and hence the formation of a water-in-oil emulsion in the soap stock be prevented or will be onlyslight.

Before the rening of vegetable and animal oils had reached the present stage of advancement, lime had been used to neutralize the free i'atty acids in oils. 'Ihe resultant neutralized oil, using this neutralizingagent, is extremely dark. Likewise, the separation of the oil from the soap the speed with which neutralizaiton of the free l lio stock containing an oil-in-water-emulsion. By

fatty acids occurs and the neutralized oil is separated from the soap stock, the formation -oi a water-in-oil emulsion is practically prevented because, the precipitated electrically neutral emulsiiiying materials and the water-insolublesoap do not have suiiicientA time to dissolve in the oil.

Ineach csmthehydroxidewillbeusedasasuspension in water, mixing with-the oil being ,elected byl any of the procedures to be hereinafter described.

The water-insoluble soapformed 'is negatively charged, and the negative charses neutralize pcsitive charges on suspensoids present inthe oil, resulting in the'electricallyneutral 'substances being included in the soap' stock formed. However, because ofthe low pH conditions as com.

pared with the pH-which obtains when rening with .causticalkalh a greater 'proportiongof the electrically neutral coloring matter will be in solution in the oil than occurs when refining with caustic alkali, and, as a resultthe neutralized oil obtained by treatmentwith reagentaforming. water-insoluble soaps is darker in color than that obtained' when refining with caustic alkali..` The l velectrically neutral coloring matter present in the oil can be removedl by treatment wlthiullers earth, but this is not as desirable as pro- Acedure of ilrst e-reilning the neutralized oil, obtained by the reagent .producing the waterinsoluble soap, with caustic alkaliwhcrezby the electrically neutral coloringl matter present in the nu win be distributed between the ou and the soap stock formed inthe refreiininggoperation in accordance with -the pH of the caustic alkali.4 This re-reiining treatment with caustic yallralialso will result in the neutralization of electrical charges on some of the rmore highly stock is incomplete, because of the formation of by adding it assuchtotheoih.

dispersed color supensoids still remaining in the neutralized oil, thereby als'p improving the color of the resultant re-reilned oil. since these additional electrically neutral particles will also be distributed in accordance with pH conditions.

Passing to another of the invention, in re-renning, superiorresults can beobtained bi! forming the caustic alkali in the oil, rather 1f the unharmed renned ou is treated with powdered sodium carbide, the'water'in the oil (or added water, if desired) will form caustic soda and acetylene gas by reaction with the carbide. The caustic soda will immediately react with the neutral oil to form a soap, the electrical charges on which will neutralize the electrical charges on some of the remaining 1118111? dispersed suspensoidsin the oil. After breaking the emulsion.- the soap and the' excess sodium carbide can immediately be separatedv from the oil in a centrifuge, leaving a dry oil containing no soap.

Ii' suiilcient ofthe highly dispersed coloring matter has been removed, the oil will be bleachable in the `ordinary mlnner.

Preferably the powderedcarblde'as a suspenl sioninadrygascousmediumismixedwiththc--` oil (or with' the oil thoroughly mixed with added water) in the form of a mist. Whereit is desired to add water. a colloid mill may beiused .m to create a 'fine dispersion of the water in a neutralizing agent, such as calcium hydrodde. barium hydroxide, strontium hydroxide or magnesium hydroxide which will form water-insoluble soaps thus preventing the formation oi' a soap the oil.

Instead of form the hydroxide of .the metal. may be' used.

time' 1 A carbide.- any organic alkali metal compound which, reacting with water, will` butyl and sodium propyl. Where the compound is soluble in a solvent such as alcohol, for example sodlium methylate, which is soluble in methyl alcohol, the compound, in solution, can be conveniently mist-mixed with the oil.

By rst drying the oil in any conventional manner, the alcoholic solution of the organic alkali metal compound may be brought in contact with the oil and the mixture formed into a mist and l mixed with a mist of water. 'I'he superior result obtained by forming the caustic in the oil is probably due to the greater activity, by analogy to nascent hydrogen. Broadly considered, this phase of the invention involves v causing parent compounds to react in a disinte- The fact is known that an emulsion of oil and.

water is negatively charged, and I have found that if such an emulsion is formed, with the water dispersed in the form of an aerosol and intimately mixed with crude oil and with the latter also in the form of an aerosol, alarge amount of positively charged colloidal material,

including the gummy constituents, is thrown outl of suspension. I have also found that the amount oi water utilized in making such an emulsion may be extremely small and is preferably less than 0.5% by volume, based on the volume of crude oil being treated. Although the invention is not limited to the use of less than 0.5% of water, and larger amounts may be used, much better results are obtained if the preferred amount oi water is employed.. '.Ihe water-treatinglossisthusminimized. Exactlyasinthe case oi' rening with y caustic soda, the emulsion is broken, preferably by collecting the mixed-mist emulsion as a liquid emulsion on a heated surface which imparts an emulsion-breaking temperature. the broken emulsion then being passed to a separating means such as a centrifuge.

It is known that allergies are produced in gcneral by protein. The proteins present in cottonseed oil are in the electrically neutral particles which may dissolvedn the oil. By minimizing the solution of these particles in the oil, in accordance with my process, I produce a refined oil having a so much lower protein content than the refined oil produced according to common procedure, as to be negligible. The protein may be present in the oil due to the emulsifying action of dissolved lecithin (electrically neutral lecithin).

In my process the rapidity of reningpractically prevents the solution of electrically neutral lecithin, and, hence, if protein is present in the oil by reason of lecithin, the protein content of the rcilned oil produced by my process will be less than in the refined oil produced by the ordinary procedure.

Cottonseed oil is typical of all vegetable and animal cils containing free fatty acids and/or electrically charged colloidal suspensions, for example peanut, soya bean, palm kernel, linseed,

2,342,042 A potassiummethylate, potassium ethylate, sodium cocoanut, ses'a'me, whale, menhaden, and shark oils, and tallow. In re-reiining, caustic alkali will probably always be'used as the saponifying agent, whether added to or formed in the oil, but in the refining of crude oil, any other suitable neutralizing agent may be used. In this connection, I have mentioned, for example, the hyroxides of calcium, barium, strontium, and magnesium. A characteristic of these latter is that they form water-insoluble soaps.

In the case of vegetable and animal oils the oppositely charged colloidal particles result from a reaction between one of the aerosols and one.

or more components of the other aerosol, but in any case both the positively charged particles and the negatively charged particles are at least momentarily dispersed in air and, while dispersed,

they are intimately commngled. In its broad1 aspect the present invention resides in the method of treating a liquid to remove electrically charged colloids therefrom, the method comprising .converting the liquid into an aerosol and while it is in this form intimately mixing it with another aerosol containing oppositely charged colloidal particles, whereby the respective charges are neutralized and the colloidal particles are thrown out of suspension. More specifically, the invention contemplates the separate formation of the aerosols before mixing them together.

I-shall now, by reference to the acompanying drawings, describe apparatus particularly suited for carrying out the objects of the invention.

In these drawings:

Figure 1 is an elevation of a complete system whereby rening or re-reilning can be carried out in accordance with the invention, this system inhcluding a centrifugal atomizer for the oil and refining agent.

Figure 2 is an enlarged view showing in axial section the centrifugal atomizer disposed in a reaction chamber which forms part of the system of Figure 1.

Figure 3 is an axial section of'a sligthly modified form of centrifugal atomizer head.

Figure 4 is a view like that of Figure 3, but

e showing parts in different adjustment.

Figure 5 is an elevation, partly in section, showing a modified form of feeding means including a two-fluid nozzle.

Figure 6 is a sectional view of an adaptation of the two-fluid nozzle of Figure 5.

Figure 7 is anaxial section of a further form Y of two-fluid feeding device.

Figure 8 is a diagram of a modied system.

' Referring to the drawings, and first to Figures 1 and 2. it will be assumed that the tank i0 contains crude cottonseed oil and the tank I I a neutralizing agent which for present purposes will be assumed to be a caustic soda solution. A pipe I2 connects the bottom of tank I0 to a pump I 3 which may be driven from any suitable source of power through avariable speed drive i4. The

`delivery of this pump is controllable by means of a hand wheel I8 mounted on a control board I'i and connected with the variable speed drive through a chain I5. The pump I3 forces the oil through a pipey i8. a flow meter i9, and a pipe 20.

Ali pipe 2| leads from the bottom of tank I I to a pump 22 driven through a variable speed device 28 whose control is effected through a chain 24 from a hand wheel 25 on the control board I 1. The pump 22 delivers through a pipe 28, a flow meter 2l, and a pipe 2l.

By adjusting the output of the pumps to obtain the required reading on the flow meters. oil

and caustic solution are delivered in the desired proportions.

Reference numeral 23 designates `generally a cylindrical reaction chamber, here shown as disposd on a vertical axis and as supported substanl s Pipe 23 is in connection with tube 83 through a tially above the level oi the oil and caustic solution tanks. The reaction chamberl 23 includes outer and inner concentrically arranged cylindrical shells 33 and 3| and top and bottom walls 32 and 33 so that a closed annular chamber 34 is provided. Steam may be introduced to the chamber 34 at 35 for the purpose oi heating the wall 3|, the chamber having abottom outlet 36.

The bottom wall 33 has a central opening 31 through which projects a cylindrical housing 33 mounted on a plate 33 bolted against theunderside of wall 33. The housing 38, which is closed at the top, provides bearings for a vertical spindie 43 which is coaxial with wall 3|. The lower end oi the spindle has fixedl thereon a pulley 4I which, through a belt 42, can be driven from an electric motor'43, Figure 1. 'I'he upper end of spindle 40 projects through and above the closed upper end of housing 38 and has a threaded portion 44 surmounted .by a tapered extremity 46. v

Reference numeral 46 designates as a whole a centrifugal atomizing and mixing head which includes a circular bottom disc portion 41 having a central downwardly extending hollow hub por-l tion 48 provided with a threaded axial bore engaging the threaded portion 44 of spindle 43, with the tapered extremity vof the spindle projecting into the hub cavity. Spaced above disc portion 41 is an annular disc portion 43 and the peripheries of the two are joined by a multiplicity of rather closely spaced blades 53, which are circularly arranged in coaxial relation with spindle 43. As here shown, the blades are oi rather ilat V-shape, in elevation, with apices pointed outwardly. Inwardly of blades 50 and concentric therewith is a cylindrical wall or basket 5I provided with numerous vertical slots 52. Received in the opening of annular plate 43 is a basket 53 having' a lower portion threaded into the cavity of disc 41, the cylindrical side walls of the basket, which are concentric with basket 53, being provided with numerous radial apertures 54. The bottom Wall of the basket 53 has a tapered opening in which is engaged part of the tapered extremity 45 of spindle 40.

The bottom wall of basket 53 has a central recess in which is threaded the lower portion of an innermost basket 55 'Whose bottom wall has a tapered opening snugly receiving the very extremity of the tapered portion 45 of spindle 43. Basket 55 has cylindrical side Walls coaxial with the spindle and provided with numerous axially extending slots. As here shown, the side walls of basket 55 terminate upwardly about half way betwen discs 41 and 43.

A plate 56 is bolted against the upper margins of an opening 51 in the top wall 32 and supports a downwardly extending yoke 63. A tube 53 extends through a central opening of plate 56 and through a packing gland 68. Tube 53 also extends downwardly and loosely through a ring 6i carried by yoke 58 at its lower end, this ring having several threaded radial bores in which portion of tube 35. The periphery oi the hand v `wheel is provided with notches engageable by a spring clip 13 so that the hand wheel may be Y yieldingly retained in any position oi angular adjustment. The caustic pipe 28 is connected with the top of tube 66 through an elbow 1I.

At its lower extremity, tube 63 is provided with a conical iiare v'I2 and the' lower end of tube 33 has threaded thereon a tting including a conical flared portion 13 like portion 12. the two constituting a conical nozzle overlying the innermost basket 56 on the axis of spindle 40 and adapted to deliver a nlm or spray circumierentially within basket 53. In order that there may be uniform peripheral delivery, the, tubes and ilares can be accurately centered by adjusting the several radial screws 53' threaded in tube 53 and engaging tube 65. Threaded in the lower end of tube 66 is a nozzle 14 which may be of a type to deliver a conical spray or nlm circumterentially and coaxially with the upper nozzle and within the innermost basket 55. Or nozzle 14 may merely project a stream downwardly against the top oi spindle 43.

Adiustably fixed on the lower portion of tube 53, is a disc 16 which, as shown in Figure2, closely overlies the top oi basket 53, preferably without contact therewith.

The bottom wall 33 of the reaction chamber is provided with an opening 16 which is connected into the housing of a three-way valve 11, one outlet port of the housing being in connection with a pipe 18 which runs to a centrifugal separatory 13 which may be surrounded by a housing 83 containing a steam coil 83. This ence numeral 31 represents a controller drum which may be slowly driven by an electric motor 38 so that through wipers in connection with the indicated circuits the various solenoid valves will be operated in a predetermined sequence.

Assuming all oi the solenoid valves to be in a normally closed position, rotation oi drum 91 will cause valve 85 to open long enough tovperare threaded adjusting screws 62 which engage the tube, the arrangement being such that the tube is supportable in coaxial relation with spindie 40 and is maintained in adjusted relation, both horizontal and vertical, by the screws 62.

mit the outflow from the reaction chamber 23 to ll tank 38, valve 11 being adjusted to direct the outflow to pipe 8|. After tank 88 is filled. valve 85 will close, and valve 86 will open to till tank 63, and after this tank is iilled, valve 34 will open so that tank 88 will empty into the centrifuge. At the same time, valve 81 will open so that tank 86 will start to ll. When it has been iilled. valve 31 will close and .valve 35 will open, so `that tank 89 will empty into the centrifuge. At the Sametime, valve al will close and valve 85 will open so that tank 88 will be refilling while tank 89 is emptying. -It will thus be seen that while one tank is filling, another is emptying, and the third is at rest. That is to say, the substance in the third tank is quiescent for a period determined by the timing of the valves, which latter, of course, depends on the rate of delivery to the tanks and their capacity. By quiescent, I do not mean that the material in the tank need be completely at rest, and, as matter of fact, it may be desirable that it be agitated. Only in unusual circumstances will the tanks be used in, the reiining of crude oil, their main purpose being to introduce a retardation or time lag between the reaction chamaecaoea are immediately -and totally entrained by the atomizing baskets and during mixing are conber and the -centrifuge. in Are-re1lning, this for a purpose which will be later explained.

In the refining of crude oil, valve 11 will ordinarily be adjusted so. asv to connect the outlet of the reaction chamber with the pipe 18 which runs directly to the centrifuge for quick gravity delivery to the latter, it being preferable to avoid the use of a pump, with its agitating effect,

although where necessary a pump may be interposed in the line. The centrifuge itself has a pull effect. With pumps I3 and 22 in operation, regulated quantities of oil and caustic solution, at the usual temperature, will be delivered, respectively, to the nozzle constituted by the flares 12 and 13, and to the nozzle 14. The head 46 is rapidly rotated, for example, at a speed of 13,000 R. P. M. I do not mean that this speed is critical, but mention it as' a speed which I have found satisfactory. The oil is delivered as a uniform circumferential spray or nlm against the Walls of basket 53 and is atomized or misted in passing through the openings 54. The caustic solution, preferably delivered by nozzle 14 as a uniform circumferential spray or film, is atomized or misted as it passes through the slots of basket 55, and is subjected to a further action in passing through the openings. of basket 53.

With the nozzles adjusted as shown in Figure 2,-

the zone of delivery of the oil in basket 53 is entirely above that of the caustic solution and, consequently, there is no contact whatever of the two until they have both emerged as mists from basket 53. Thereupon they areimpinged -together and are subjected to an intense mixing action as they pass under centrifugal force through the slots 52 of basket 5| and between the blades 51, emerging from the latter as a homogeneous mist mixture which is projected circumferentially against the heated wall 3|.

lDisc 15 is usedwhere it is desired to limit air entrainment. Ordinarily it may be omitted.

While superior results are obtained by separately forming the mists, as just described, and then mixing them, the adjustment of the nozzles may be such that there will be contact of the liquids prior to atomization. That is to say, the caustic solution might be sprayed into and distributed in the oil vand the combined spray then converted to a mist mixture. This and other variations in the manner of supplying the substances to thel atomizer head will be discussed hereinafter.

In any event, the intimately mixed substances emerge from the atomizing and mixing head as a-k homogeneous mist mixture which has been instantaneously formed from the two substances.

It will be observed that, upon emergence of the oil and caustic solution from the nozzles, they posed between the inner baskets iinedby the top and bottom walls o! the head so vthat the entire delivered quantitieaof the 'substances are present in the mixture and the mixture is expelled or directed away so that when once formed it has no further contact with any unmixed constituent andits uniformity is maintained. Every possible precaution should be taken to insure uniformity and to this end, as .regards the feeding step, the nozzles are set to be exactly coaxial with the head and to have a, uniform peripheral delivery. When the feed is thus uniform, the head will deliver radiallya mist mixture which is homogeneous throughout its circumference. v At this point it may be mentioned that, in original refining, basket or ring 5| may be omitted in order to prevent a too violent emulsifying action. In re-reiining, however, the rened oil contains practically no emulsifying materials and, consequently, in order to promote emulsication, the basket 5| is used, and. of course, additional perforated rings may be inter.

and the peripheral blades, if desired.

By the time the mixture emerges from the head, substantially all of the free fatty acids in the crude oil have been neutralized by the caustic soda. This is believed to be so, although it may be that some reaction occurs during the passage of the mist to Wall 3| of the reaction chamber. It is at least known that the reaction has been substantially completed by the time the mist reaches wall 3|. In an actual installation, utilizing an eight inch head, rotating at 13,000 R. P, M., the time elapsing between the delivery'of the liquids by the nozzles and the emergence of the mixed mist from the head is about 1/uui of a second. In the mentioned installation the diameter of wall 3| was four feet.

Since the neutralization of the fatty acids oc curs as the result of the intermingling of particles of oil and caustic solution which are each in a highly dispersed state, the soap which results from the reaction is also in a similarly divided state, and the negative charges on these extremely minute colloidal particles of soap neutralize the positive charges on the colloidal impurities in the oil. y

Since the present process of refining crude oil does not rely on the utilization of any soap formed lby the reaction between the caustic soda and the. neutral oil, it might be thought to be unnecessary touse any excess of caustic beyond that theoretically required to neutralize the free fatty acids. As a practical matter, however, a very slight excess of caustic is employed in order to increase the pH, or, in other words, in order to lower the hydrogen ion concentration. However, the excess caustic which is used for this purpose is not comparable in amount to the excess caustic which was necessarily used in previous processes, and any saponication of neutral oil which occurs is negligible and not relied upon for the removal of the colloidal impurities.

I have found that after the colliodal impurities have been rendered electrically neutral, they are slightly soluble in the oil, and also in the water which is present as the result of the introduction of the caustic soda solution. I have also found that their solubility in water is greater than their solubility in oil and that'the solu-v bility inboth the water andthe oil depends on the hydrogen ion concentration. As the hydrogen ion concentration increases, the solubility in oil of the electrically neutral colloidal impurities increases, and, conversely, a low hydrogen ion concentration results in increased solubility of the electrically neutral colloidal impurities in water. Therefore, since the distribution of the electrically neutral colloidal particles in the water and the oil depends on the hydrogen ion concentration, I use sufficient caustic to reduce the solubility of the particles in the oil and to increase their solubility in the water. Obviously, the coloring matter dissolved in the water is separable from the oil as a part of the soap stock.

The amount and strength of the caustic soda solution required depend on the type andquality of the oil being treated. In the refining of crude oil in accordance with my process, very low refining losses, with good color-reduction, are obtained by using an excess of only 0.2% to 0.3%. The strength of the solution is adjusted so that the oil-soap stock emulsion will resolve itself into only two layers, one of soap stock and one of oil,

solution, and one of oil, a special construction of separating centrifuge would have to be used to prevent the building up of an intermediate layer of soap between the oil and caustic solution, since otherwise the soap layer so formed would discharge with the oil rather than with the caustic solution. In the practice of the present process, the formation of a separate soap layer is prevented by using an excess of caustic soda which is dependent upon the ratio of the colloidal matter in the oil to the soap stock. Where the ratio of colloidal matter to soap stock is high, such as occurs in the case of a low free acid, slow-breaking type of crude cottonseed oil, a greater excess of caustic alkali must be used because of the higher rate of consumption of the excess caustic by reason of the greater emulsification occasioned` by the larger proportion of colloidal matter in the soap stock.. In oils of this type, I have found that the use of from 0.2% to 0.3% excess caustic gives satisfactory results. On low free acid crude cot tonseed oil having a low ratio of colloidal matter to soap stock, I may use as little as 0.1% excess caustic. From this, one would expect that in the case of high free acid oils, where the ratio of colloidal matter to soap stock is low, the use of 0.1% excess caustic would be indicated. However, I have found that I can use as high as 0.4% excess caustic without causing the formav tion of a third layer, because the large surface of soap stock, due to the high free acid, acts to increase the saponiiication of neutral oil, thus reducing the available caustic. If only 0.1% excess caustic were used on high free acid oils, the excess would be consumed by saponiiication so rapidly that the hydrogen ion concentration would be increased with consequent increase in refining loss because of the solution of some of the electrically neutral colloidal matter in the oil forming a water-in-oil, emulsion. As ageneral rule, it may be said that regardless of the fatty acid content of the oil, the excess caustic may be only slightly beyond that theoretically required for neutralization. For example, I haveI successfully used an excess of 0.2% in refining a cottonseed oil having a free fatty acid content of 0.8%, and the same excess in refining a crude cottonseed oil having a fatty acid content of 8%.

The concentration, of the caustic solution should be such that'the-resultantl soap stockwill holdall the water introduced by the caustic solution. I have found that a water content of from 30% `to 35% in the soap stock is satisfactory, but in the practice of my process, using only a slight` excess of caustic (which means the addition of' a minimum of water by way of the caustic solution) I commonly secure a soap stock having a water content around 23% or 24%, and in some instances an even drier soap stock is secured.

It has been stated that the solubility of the colloidal coloring matter in the oil increases as the hydrogen ion concentration increases, and that the solution of the coloring matter in the oil is avoided as much as possible by control of' the hydrogen ion concentration. In addition to this factor, I have found that for any given hydrogen ion concentration, the amount of electrically neutral colloidal matter which dissolves in the oil, depends upon the length of time that this colloidal matter is in contact with the oil, and upon the intimacy of the contact between the colloidal matter and the oil. Therefore, the more quickly and unagitatedly the oil and soap stock are passed to the centrifuge after the electrical charges on the colloidal matter have been neutralized, the less will be the solution of the colloidal impurities in the oil. This is why I prefer to deliver from the reaction chamber directly to the separator by gravity, thus 4reducing the factors of time and interaction to a minimum. Under unusual circumstances. it may be desired to allow the soap, which has been formed in a fraction of a second, to agglomerate for the purpose of facilitating the separation of the soap stock from the oil. In these rare cases the rest tanks 88, 89- and 90, or an equivalent provision, would be used. Obviously, in view ofthe longer time between mixing and separation, when such rest provisions are used, more of the alkaline refining agent has to be used in order to maintain the hydrogen ion concentration up to separation.

The mist or aerosol circumferentially projected against the wall 3|, collects on the latter as a liquid emulsion, and ows downwardly thereon as a thin layer or lm. By circulating steam in the chamber 34, wall 3i is heated sutilciently so that a breaking temperature, usually' around F., will be imparted to the emulsion by the time it reaches the bottom wall of the reaction chamber. Ordinarily the broken emu1 sion is passed directly to the centrifuge through4 the pipe 18, although if desired it may be sent to the centrifuge by way of the rest tanks.

As illustrative of the efficiency of my process, as compared with present practice, I give below data on the refining of a car of cottonseed oill in accordance with my process, and on the re-A i suits of a laboratory refining test of the same oil,

the oil having a free fatty acid content of 1.3%. The laboratory test results are practically the same as those obtained in vkettle rening.

l Red.

' charge from the centrifuge,

Details of Fashtest vWeight of crude oil reilned---- pounds 59,950 Weight of refined oil -do 56,980 Refining loss -do .2,970 Rening loss, wet oil -per cent-- 4.95 Refining loss. dry clean oil ..do 5.14

Analysis refined oil Per cent Moisture 0.18 Soap 0.02

Analysis soap stock Per, cent Moisture 24.4 Neutral oil 25.2 Total fatty acids 58.0

When a vegetable oil, such asfcottonseed oil, is refined with a caustic soda solution in accordance with the processes in common use, the resultant refined oil contains a considerable amount of suspended soap stock necessitating washing the oil one or two times with water to remove the soap stock. In refined oil produced by my process, there is no appreciable suspended soap. .This is due to the fact that because of the rapidity of my process the electrically neutral colloidal material, which, when dissolved in the refined oil will produce a water-in-oil emulsion, is practically absent, and, therefore, no appreciable water-in-'oil emulsion is formed. The soap stock suspended in reiined oil obtained by relining in accordance with the procedures in common use, constitutes the water phase of a Waterin-oil emulsion.

When the refined oil produced in accordance with my process is discharged from the centri- Iuge, it is clear, gradually becoming cloudy on cooling. This cloudiness is due to water containing soap in solution, which water is in solution in the refined oil at the temperature of the disapproximately 140 F. As' the oil cools, the Water being less soluble in cool oil precipitates out, carrying with it the soap that was in solution in this' water. By cooling the refined oil produced by my process to below 100 F., the water and the soap dissolved in the water can be removed suflioiently to produce a merchantable oil by simple filtration with a filter aid without the necessity of washing with subsequent vacuum drying as is now the practice. The results of numerous analyses have shown that refined oil produced by my process contains approximately .18% of water and .02% of soap, as illustrated in the above example.

In the common procedure used in re-rening cottonseed oil, about 2% of a 14.7% (20 B.) caustic soda solution is used. Because the re- !ined oil contains practically no emulsifying materials, only a small amount of this caustic soda saponies the neutral oil at the temperatures used in re-reilning, soap stock obtained consists of, a layer of soap and a layer of unconsumed caustic liquor which renders `it impossible to obtain a. continuous separation in an ordinary centrifuge of the-reretlned oil and the soap stock. This difficulty in the handling of a two-layer soap stock has been discussed above in connection with the refining of crude oil.

In my process of re-rening, I may use even lass than 0.25% of a 20% solution of caustic soda, equivalent to an excess of about 0.05%. Because o! the method of mist mixing, sumand, as a result, the

cient saponification occurs in the .01 second during which the caustic solution and oil are passing through the centrifugal atomizer to saponify suilicient oil to reduce the color. There is very little fatty acid content in refined oil, and consequently in re-rening, in accordance with my process, I rely on the soap formed from the saponiiication of the neutral oil itself t'o provide electrical charges for the neutralization of electrically charged colloidal matter which escaped neutralization in original refining.

By -introducing a suitable time lag atsome point between mixing and separation, for example, by the use of the rest tanks 88, 89, and 80, the causticis consumed to such a point that only a one-layer soap stock is produced Due to the use of the slight excess of caustic, this consumption occurs without any material loss of neutral oil. As in original reiining, the excess is present only for the purpose of maintaining a'low hydrogen ion concentration up to separation so as to decrease the solubility of the electrically neutral particles in the oil.

Aside from the preferred utilization of time' lag or retardation, as above discussed, the procedure in re-rening is exactly the same as in the reilning of crude oil, with the exception that since in re-reflning an enhanced emulsifying action of the atomizer is desired, the basket 5| is used, whereas itis preferably omitted in original refining.

An atomizing and mixing head which has an action vintermediate the action of the head 46 when the basket 5| is present, and in re-refining, and the action of the head when the basket is absent, as in original refining, is shown in Fig. 3. In this ligure reference numeral |00 designates a bottom disc and reference numeral |0| a top annular disc whose peripheries are joined by a multiplicity of slightly spaced apart blades |02, the two discs being held together, as here contemplated, by a small number, for example, four, of bolts |03, proper spacing of the discs being afforded by spacing collars |04 which surround the bolts. Reference numeral |05 designates the oil basket, and reference numeral |06 the caustic basket. 'Ihe nozzles are the same as before, and, with their indicated adjustment, the oil is being sprayed into the basket |05 in a zone above that in which the atomized caustic is received. Consequently, the substances are separately misted before mixing. 'I'he spacing collars have some emulsifylng effect, but much less than the ring 5| of Figure 2.

In Figure-4 a nozzle |01, which delivers in a much iiatter cone than the nozzle 14, is shown as substituted for the latter.y Furthermore, the fitting of which the ange I3 is a part has been threaded downwardly on tube 65 and tube 59 has been lowered to bring its flare 12 into original spacing with flare 13, so that the nozzle operatesaas before. Basket |06 has been unthreaded and removed, so that basket |05 is solely relied on for atomization, and the two sprays or lms are shown as merging prior to striking the walls of the basket. Due to the uniform inter-distribution of the substances prior to misting, the color removal may be ranged so that the sprays or nlms delivered thereby will impinge each other.

Figure 5 shows a still different arrangement for eecting feed of the two substances. In this iigure, reference numeral |08 designates the top wall of a jacketed reaction chamber having an opening 09 on the margins of which rests a neck H held in place by a top plate |||and clamping bolts H2. A pipe ||3 is passed through an opening in plate and is vertically and laterally adjustable by adjustment of bolts'ild. An oil vpipe H5 and a caustic solution pipe i|6 extend through pipe H3 and are secured in position in end caps of the latter.

Referring also to Figure 6, reference numeral ||1 designates a tubular nozzle body having parallel lateral openings ||0 and ||9 into which the oil and caustic solution pipes are respectively ied through suitable elbow connections by which the nozzle body is held in coaxial relation with an atomizer head |20. The nozzle body has a threaded extremity with which is engaged a nozzle tip -|2|. The opening H9 connects with a chamber |22 having a bottom wall in which is threaded a tube |23 which constitutes an inner nozzle coaxial with the outer nozzle. At the lower vend of tube |23 spiral iins |24 are disposed in the annular space between the nozzle tips. The tip |2| projects within an atomizing basket |25 of the atomizing and mixing head, this basket corresponding, for example,- to the basket |05 of Figure 4. No innermost basket like the basket |06 of Figure 3 need be provided, although one may be, if desired.

The described two-fluid nozzle delivers a full cone spray Vinto the bottom of basket |25, which triiugal atomizer, the substances may be fed thereto in various ways. In Figures 2 and 3, the substances are fed separately and are not mixed until after they have been separately atomized. In Figure 4, the nozzle adjustment is such that sprays or iilms of the separately fed substances are impinged together and the combined product is atomized. In Figure 5, the separately fed oil and caustic, contact for an instant as liquids at the nozzle outlet, while in Figure 6, the period of liquid contact is increased in accordance with the length of the extension. In all these forms, the substances are fed coaxially with reference lto the atomizer head. In Figure '7 the caustic solution is discharged laterally into the oil stream at a point more or less remote from the discharge oriiice of the nozzle, and the latter, if no sprays were desired to be formed, could be omitted, the

spray is instantaneously reduced to a homogeneous mist mixture as a result of passage through the basket apertures. As many outer baskets as desired may be provided, but, for all practical purposes, the head may be exactly as shown in Figure 4.

Obviously, the oil and caustic contact in liquid form in the nozzle, but the preliminary distribution contributed by the nozzle is a factor which improves the color removal, although the refining loss is somewhat greater than in the case of separate mist mixing. It will be understood that the head |20 projects the mist mixture against heated walls of the reaction chamber, as before.

In Figure 6, the tip |2| of the nozzle has a tubular extension |26 threaded thereon and a. downwardly tapering tip portion |21 is threaded on the lower end of the extension. Threaded in portion |21 is a plug |28 having a relatively restricted bottom opening |29 surmounted by an upwardly flared portion |30. This form of nozstream being made to strike centrally in the atomizer basket. In all cases, however, the'substances are subjected to rapid and uniform mixing in mist form. The feeding devices mayeiect distribution of the caustic solution in the oil, but the real mixing step takes place in the atomizer head while the substances are in total mist condition. The substances, it will be seen,- are fed from the separate sources to the atomizing and mixing means in a sustained flow, with the substances separate until delivery to the atomizing and mixing means, or merged in advance thereof, but maintaining their original proportions up to' the delivery rpoint constituted by the atomizing and mixing means. By "sustained flow, I mean flow which is unretarded by anything such as a mixing tank interposed between original feed and delivery to the atomizing and mixing means. The original proportions are, of course, maintained in the atomizing and mixing means so that a continuously uniform homogeneous mist-mixture-is discharged thereby.

According to prior rening practices, the oil and caustic are brought together while both are in liquid form and they retain this form throughout the treatment. When brought together, the liquids are adsorbed to each other, forming ag gregates. In addition, saponiiication of the fatty acids in the oil occurs, forming an emulsion, so

. that the aggregates of caustic solution,l soap, and

zle is used in the same manner as shown in Figure 5, the pipes being elevated somewhat in order to position the lower end ofthe nozzle properly in the atomizer basket. The advantage of this form of nozzle is that it produces a hollow cone spray with more uniform radial distribution oi the substances than when the extension is omitted. i

In Figure '7, the oil pipe |3| `and caustic rsolution pipe |32 are connected into a T |33, a nozzle |34 being threaded into the T in alignment with the oil pipe, this nozzle as here shown, being like the nozzle extension of Figure 6. The caustic is injected laterally into the oil stream and the two substances, inter-distributed, are discharged as a hollow cone spray into the atomizer basket.

oil are large. Because the amount of caustic s olution is small compared to the amount of oil being reilned, in order to contact all of the oil with the caustic solution, it is necessary to break the aggregates by agitation. This requires time during which the excess caustic present is saponifying neutral oil, thus increasing the refining loss. Since excess caustic is required to be present at the end of the reiining operation, so as to obtain a satisfactory color of the oil, a large excess of caustic is required at the beginning'in order that an excess may be present at the end, and, the higher the free fatty acid content of the crude oil being refined, the greater must be the excess. Considering the fact that the aggregates will begin to form immediately the two liquids are brought together, it follows that, in the practice of the present invention the best results, as regards saving of neutral oil, are obtained when the initial contact of the substances occurs when both of them are in mist condition. However, so long as the mist-mixing principle is used, the oil and caustic solution can be brought together initially in liquid form so long as the merged substances are disintegrated prior to major consumption of the caustic.

The system shown in Figure 8 is adaptable various procedures under the invention. Tanks |45 and |46 are connected, through shut-oil? and regulating valves |41 and |48, with a vertical tube |49 which corresponds to the tube 59 of Figure 2. Reference numeral |50 designates a tube corresponding to the tube'65 of Figure 2. l These tubes have at their lower ends nozzles, for

example like those of Figure. 2, adapted vto deliver into a centrifugal atomizer or other suitable mixing mechanism in the reaction chamber |5|. The upper end of the tube |50 can be connected by means of a three-way regulating valve |52 either with a pipe |53 or a pipe |54, the latter leading from a blower |55 to which pulverized material can be i'ed from a hopper |56. Reference numeral |51 designates the discharge pipe for the reaction chamber, this pipe leading through a three-way valve |58 to a three-way valve4 |59 by means of which flow in pipe |51 can be directed to the separator |60.

A branch |6| leads upwardly from the threeway valve |58 to the bottom of a tank |62 which may be equipped with a steam jacket |63. Disposed adjacent the bottom of the tank is an agitating paddle |64 driven from an electric motor |65. A suction pipe |66-has a vertically adpustable extension |61 projecting downwardly in tank |62. Pipe |66 leads to a pump |68 of any suitable type, the pump being adapted to deliver through a pipe |69 to the three-way valve |59 and thence to the separator.

In caustic rening of crude oil, the oil may be contained in tank |46 and the caustic solution 4may be introduced through pipe |53 in proportions as controlled by the adjustment of the valves |58 and |59 being suitably adjusted for this purpose.` In re-refining. however, valve |58 can direct the outilow into tank |62, paddle' |64 being' driven so as to exert a down-pull on the liquid in the tank so that the liquid is agitated and formation of a top layer of soap froth is impeded. The extension |61 is adjusted so that its lower end is below the liquid level in the tank and the liquid is withdrawn bv pump |68 and passed to the separator, valve |59 being adjusted for this purpose. In re-reiining, the reaction chamber may be unheatedand heat may be applied at some other point, for example to the liquid in tank |62 by means of steam jacket |63. Provision of the tank |62 is for the purpose of interpolating a delay between disintegration and separation so as to permit the-refining agent to be consumed to such a point, with accompanying agglomeration, that only a one-layer soap stock will be formed.

Considering tnk |46 to contain unclaried refined oil and hopper |56 to contain iinely powdered sodium carbide. by opening valve |48 and driving the blower |55 with valve |52 adjusted to connect pipe |54 with tube |50, the oil and the powder, with the latter highly dispersed in air, will be fed to the atomizer. and the reaction product can be run directly to the separator through pipe |51. The sodium carbide can be dispersed in gases other than air. if desired.

Tank |45 may contain, for example, a solution of sodium methylate` in methyl alcohol and tank |46 may contain substantially dry oil. 'Ihe two may be admitted in regulated proportions to tube |49, and water for the reaction can be supplied through pipe |53 to tube |50. If the oil, on the otlr hand, has a suilicient water content, it may be delivered alone from tank 46 to tube |49 and the sodium methylate solution maybe supplied through pipe |58 to tube |50.

In the preliminary treatment of crude oil for the removal of the dispersion constituted by the gums, etc., the crude oil may be fed from ltank |46 to tube |49 and the water, whiclnhere mair be considered as constituting the refining agent, will be introduced through pipe |53.

It will be evident that the described supply `systems, which have been assumed to terminate in the reaction chamber in nozzles such as are shown in Figure 2, might terminate in any of the.

. hereinbefore described feeding devices. In fact any other appropriate forms of feeding devices and collecting arrangements may be used, and the feeding devices may themselves constitute misting means, or may have suitable misting.

means associated therewith.

While the system of Figure l was described with particular reference to rening with a caustic soda solution, obviously it is not limited to such use and can be utilized in the preliminary water treatment, in refining by forming the caustic in the oil, and rening with other agents, such as those which will produce water-insoluble soaps.

I have hereinbefore explained what I mean by a mist" or an aerosol. I use the term "spray as including not only mists or aerosols, but also a coarser state of sub-division, involving, for example, drops or globules of substantial size, and lms. The expression disintegrated condition" is used, as covering a broken-up condition generally, whether ne or coarse, unless otherwise indicated. The term refining as used in the claims, is generic to crude oil refining and rerening unless otherwise indicated. Mist-mixing means the formation and mixing of mists. Under this term, the oil and refining agent solution can be misted and mixed without previous contact in liquid form, or they can be merged in liquid form prior to misting and mixing so long as the period of mergence is insuillcient to permit major reaction to take place prior to the mistmixing.

While I have given preferred examples of procedure, it is to be understood that the vinvention includes variations within the scope of the claims which follow. This application is a continuationin-part of my application Serial No. 349,989, filed August 2, 1940, which latter was led as a continuation-in-part of my application Serial No. 198,493, tiled March 28, 1938. The apparatus herein disclosed and method of mist-mixing a plurality of substances in general as capable of being carried out in the use of such apparatus, is

claimed in my copending application Serial No.

438,954, led April 14, 1942.

I claim:

1. The method of removing a suspension of positively charged colloidal particles from glyceride oils, which comprises the steps of converting the oil to an aerosol, separately converting a neutralizing agent to an aerosol, intimately mixing the two aerosols whereby the neutralizing agent-reacts with the free fatty acids in the oil and forms a highly dispersedcolloidal soap, intimately mixing the colloidal dispersion of soap with the dispersion of oil whereby the positive charges on the colloidal particles are neutralized by the negative charges on the colloidal soap and are coalesced with the soap, and separating the soap stock from the oil.

2. The method of removing a suspension of positively charged colloidal particles from glyceride oils, which comprises the steps of converting the oil to an aerosol, separately converting a solution of caustic alkali to'an aerosol, intimately mixing regulated quantities of the two aerosols whereby the caustic alkali reacts with the free fatty acids in the oil and forms a highly dispersed colloidal soap, the amount of caustic alkali used being only slightly in excess of that theoretically required to neutralize the free fatty acids regardless of the free fatty acid content of the oil being refined, intimatelymixing the colloidal dispersion of soap with the dispersion of oil whereby the positive charges on the colloidal particles are g neutralized by the negative charges on the colloidal soap and are coalesced with the soap, and separating the soap stock from the oil.

3. The method of removing a suspension of positively charged colloidal particles from glyceride oils, which comprises the steps of converting the oil to an aerosol,l separately converting a solution of caustic alkali to an aerosol, intimately mixing the two aerosols whereby the caustic alkali reacts with the oil and forms a highly dispersed colloidal soap, intimately mixing the colloidal dispersion of soap with the dispersion of oil whereby the positive charges on the colloidal particles are neutralized by the negative charges on the colloidal soap and are coalesced with the soap, allowing the mixture of oil and soap vstockl to remain quiescent to agglomerate the soap stock harticies, and separating the soap stock from e oil.

4. The method of removing a suspension of` positively charged colloidal particles from glyceride oils, which comprises the steps of converting the oil to an aerosol, separately converting a solution of caustic alkali to an aerosol, intimately mixing the two aerosols whereby the caustic alkali reacts with the oil and forms a highly dispersed colloida1 soap, intimately mixing the colloidal dispersion of soap with the dispersion of oil whereby the positive charges on the colloidal par-y ticles are neutralized by the negative charges on the colloidal soap and are coalesced with the soap, introducing a portion of the mixture of oil. and soap stock into a receptacle and allowing it to remain at rest therein to agglomerate the soap stock particles, introducing an additional portion of the mixture into a second receptacle while the iirst portion is at rest in the i'lrst receptacle, and

introducing a third portion of the mixture into a third receptacle while discharging the mixture from the first receptacle, discharging the mixture from the second receptacle while allowing the mixture in the third receptacle to remain at rest, and discharging the mixture from the third receptacle while the first receptacle is being refilled, conducting the mixture discharged from the respective receptacles to a separator, and separating the soap stock from the oil.

5. The method of removing a suspension of positively charged colloidal impurities from glyceride oils, which comprises 'the steps of converting the oil to an aerosol, separately converting a neutralizing agent to an aerosol, intimately mixing the two aerosols whereby the neutralizing agent reacts with the free fatty acids in the oil and forms a highly dispersed `colloidal soap, in-

' timately mixing the dispersion of soap with the dipsersion of oil whereby the negative charges V on the soap particles neutralize' the positive charges on the impurities in the oil, collecting the resulting mixture as a liquid emulsion, heating the emulsion to a'breaking temperature, and separating the soap stock from the oil.

. mixed,

glyceride oils, which comprises the steps of converting the oil to an aerosol, separately convert- 4 ing a neutralizing agent to an aerosol, intimately mixing the two aerosols whereby the neutralizing agent reacts with the free fatty acids in the oil and. forms` a highly dispersed colloidal soap,

'intimately mixing the dispersion of soap with the dispersion of oil whereby the negative charges on the soap particles neutralize the positive charges on the impurities in the oil, projecting the resulting mixture against a heated surface whereon the mixture collects as a liquid emulsion and a breaking temperature is imparted to the emulsion, 'and separating the oil from the soap stock. 4

7. The method oi refining glyceride oils with a neutralizing agent, said method comprising forming a `wet mist of the neutralizing agent, separately forming a mist'of the oil, and' impinging the mists together so that the two are intimately mixed and initial contact of the substances occurs while both are entirely in mist form.

8. The method of reiining glyceride oils with a solution of caustic alkali, said method comprisingforming a wet mist 'of the alkaline solution, separately forming a vmist of the oil, and impinglng the mists together so that the two are intimately mixed and initial contact oi the substances occurs while both are entirely in mist form. the amount of alkaline solution used being only slightly in excess of that theoretically -required to neutralize the free fatty acids reand a neutralizing agent circumferentially from a common axisto disintegrate them separately into mists, and impinging the mists together in an annular zone so that the two are intimately mixed.

10. The method of refining glyceride oils which comprises separately projecting the oil and a neutralizing agent circumferentially vfrom a common axis to disintegrate them separately into mists, impinging the mists together in an annular zone so that the two are intimately centrifugally projecting the mixture against a circumscribing heaated surface whereon the mixture collects as a liquid emulsion and a breaking temperature is imparted to the emul- -Y sion, and separating the soap stock from the oil.

l1. The method of refining glycerlde oils which comprises separately projecting the cil `and a neutralizing agent circumferentially from a common vertical axis to disintegrate them separately intoil mists, impinging the mists together in an annular z one so that the two are intimately mixed, centrifugally projecting the mixture againstv circumscribing heated vertical walls whereon the mixture vcollects as a liquid emulsion and down which the emulsion can ow to attain a breaking temperature, and separating the soap -stock-from the oil. A

12. The method of refining glyceride oils containing free fatty acids land electrically charged colloidal particles which comprises converting the oil to an aerosol, separately forming another aerosol of caustic alkali, andintimately mixing the two aerosols whereby soap stock is formed and acts to neutralize electrical charges on said particles, the caustic alkali being used in silght excess over that theoretically required to neutralize the free fatty acids whereby to maintain a low hydrogen ion concentration so as to decrease the solubility of the electrically neutral particles in the oil.

13. The method of re-ning glyceride oils with a solution of caustic alkali, said method comprising forming a wet mist of the alkaline solution, separately forming a mist of .the oil,

and impinging the mists together so that the two will be intimately mixed and initial contact of the substances occurs while both are entirely in mist form, the amount of alkaline solution used being only slightly in excess of that theoretically required to neutralize the free fatty acids and being consumed to such a point that only a one-layer soap stock is produced.

14. The method of re-reiining glyceride oils with a solution of caustic alkali, said method comprising forming a wet mist of the alkaline solution, separately forming a mist of the oil, and impinging the mists together so that the two will be intimately mixed and initial contact of the substances occurs while'both are entirely in mist form, the amount of alkaline solution used being less than 0.05% in excess of that theoretically required to neutralize the free fatty acids.

15. The method of refining glyceride oils with a neutralizing agent, said method comprising forming a wet mist of the neutralizing agent, separately forming a mist oi the oil, impinging the mists together so that the two are intimately mixed ind initial vcontact of the substances occurs while both are entirely in mist form, collecting the resulting mixture as a liquid emulsion, heating the emulsion to a breaking temperature, and separating the soap stock from the oil.

16. The method of refining glyceride oils which comprises separately feeding the oil and a re` flning agent in regulated proportions, merging the fed substances, subjecting the merged substances to a mechanical action which instantaneously mixes the substances and expels them as a homogeneous mist,'collecting the mist under emulsion forming conditions as a liquid emulsion on a heated surface, imparting a breaking temperature to the emulsion from said surface, and separating the soap stock from the oil.

17. The method of refining glyceride oils which comprises separately feeding the oil and a reiining agent in regulated proportions, merging the fed substances, subjecting the merged substances to a centrifuga1 action which instantaneously mixes the substances and expels them circumferentially as a homogeneous mist, collecting the mist under emulsion forming conditions as a liquid emulsion on a heated surface, imparting a breaking temperature to the emulsion from said surface, and separating the soap stock from the oil. v

18. The method of refining crude glyceride oils which comprises mixing the oil as a mist with a mist of a refining agent which Will react with the free fatty acids in the oil to form a Water-insoluble soap, collecting the mist mixture as a liquid emulsion, and immediately and rapidly breaking the emulsion and separating the soap stock from the oil so as to minimize the formation of a water-in-oil emulsion.

19. The method of removing positively electrically charged particles from glyceride oils which comprises forming an emulsion having negative electrical charges by mixing the oil with water while both are in inist form, whereby the electrical charges on the emulsion neutralize those on the charged particles in the oil, and separating the electrically neutral particles and water from the oil.

20. The method of removing positively electrically charged particles from glyceride oils which comprises forming an emulsion having negative electrical charges by mixing the oil with water while both are in mist form, whereby the electrical charges on the emulsion neutralize those on the charged particles in the oil, collecting the mist mixture as a liquid emulsion on a heated surface, imparting a breaking temperature to the emulsion from said surface, and separating the electrically neutral particles and water from the oil.

21. The method of removmg colloidal material from glyceride oils which comprises the steps of converting the oil to an aerosol, separately converting a relatively small amount of water to an aerosol, intimately mixing the ,oil and water when both are in the form of an aerosol, and then separating the resulting sediment from the oil.

22. The method of removing a suspension of positively charged colloidal material from glyceride oils which comprises the steps of converting the oil to an aerosol, separately converting a relatively small amount of water to an aerosol, intimately mixing the oil and water when both are in the form of an aerosol to produce an emulsion which is negatively charged, allowing the negative charges on the emulsion to neutralize the positive charges on the colloidal material, thereby throwing the latter out of suspension. and then separating said material.

23. The method of removing a suspension of positively charged phosphatide containing gums from glyceride oils which comprises the steps of converting the oil to an aerosol, separately converting approximately 0.25% of water to an aerosol, intimately mixing the oil and water when both are in the form of an aerosol to produce an emulsion which is negatively charged, allowing the negative charges on the emulsion -to neutralize'the positive charges on the phosphatide containing gums, thereby throwing the ,latter out of suspension, and then separating said gums. 4

24. The method of removing a suspension of positively charged phosphatide containing gums from glyceride oils which comprises the steps of converting the oil to an aerosol, separately converting an amount of water not exceeding 0.50% to an aerosol, intimately mixing the oil and water when both are in the form of an aerosol to produce an emulsion which is negatively charged, allowing the negative charges on the emulsion to neutralize the positive charges on the phosphatide containing gums, thereby throwing the latter out of suspension, and then separating said gums.

25. The method of removing a suspension of positively charged colloidal material from glyceride oils which comprises the steps of converting the oil to an aerosol, separately converting a relatively small amount of water to an aerosol, intimately mixing the aerosols bypassing regulated quantities of through openings in the side Walls of concentric rings rotating at a speed of the order of 13,000 revolutions per minute, the oil and water being caused to pass through the openings in the rings by centrifugal force and being disintegrated into colloidal particles dispersed in air and being inoil and water separately timately mixed by the action of the rotating rings, collecting the mixture of oil. water and coagulated material resulting from this treatment and separating the oil from the coagulated material.

26. The method of removing colloidal material from glyceride oils which comprises the steps of converting the -oil to an aerosol, separately converting a relatively small amount of water to an aerosol. intimately mixing the oil and water when both are in the form of an aerosol, promoting coagulation by heating the mixture of oil and water to approximately 140 F., and then separating the resulting sediment from the oil.

27. 'I'he method of removing a suspension of electrically charged colloidal particles from a glyceride oil, which comprises the steps of converting the oil to an aerosol, separately forming an aerosol of another' substance which will react with a component of said oil to form a product electrically charged oppositely to said colloidal particles, intimately mixing the separately formed aerosols whereby to effect said reaction and whereby said product is immediately dispersed as colloidal particles in the mixture of aerosols, the oppositely charged colloidal particles neutralizing each other and being thrown out of suspension, and separating the precipitated particles from the`oil.

28. The method of rening glyceride oils which contain free fatty acids and electrically charged colloidal particles, which comprises intimately mist-mixing the oil and a caustic alkali refining agent whereby soap stock is formed and acts to neutralize electrical charges on said particles, and separating the soapstock from the oil, the

method being characterized by the use of the caustic alkali reiining agent in an amount which is only slightly in excess of that theoretically required to neutralize the free fatty acids, the said ex'cess being substantially only that necessary to maintain a low hydrogen ion concentration until separation of the soapstock from the oil whereby to decrease the solubility of the electrically neutrai particles in the oil.

29. The method of refining glyceride oils which contain free fatty acids and electrically charged colloidal particles, which comprises intimately mist-mixing the oil and a caustic alkali refining agent whereby soapstock is formed and acts to neutralize electrical charges on said particles, and immediately and rapidly separating the soapstock from the oil, the process being characterized by the use of the reiining agent in such small excess over that theoretically required to neutralize the free fatty acids that an amount insufficient to cause the formation of a two layer soapstock will be present at the time of said separating. n

30. The method of re-refining glyceride oils which contain free fatty acids and electrically charged colloidal particles, 'which comprises intimately mist-mixing the oil and a caustic alkali refining agent whereby soapstock is formed and acts to neutralize electrical charges on said particles, and separating the soapstock from the oil, the process being characterized by the use of a slight excess of the reiining agent over that theoretically required to neutralize the free fatty acids in the oil and by the interpolation of such delay between said mixing and said separating as to permit the renning agent to be consumed to such a point while maintaining the hydrogen ion concentration that only a one-layer soapstcck is produced.

31. The method of refining glyceride oils which comprises mist-mixing the oil and a refining agent in regulated-proportions under emulsion forming conditions, collecting the `mist-mixture as a liquid emulsion on a heated surface, imparting a breaking temperature to the emulsion from said surface, and separating the soapstock from the oil.

32. The method of rening glyceride oils which comprises mist-mixing the oil anda refining agent in regulated proportions under emulsion forming conditions; circumferentially projecting the mistmixture from an axis and against a circumscribing heated surface whereon the same collects as a liquid emulsion, imparting a breaking temperature to the emulsion during ow on said surface, and separating the soapstock from the oil.

33. The method of refining glyceride oils which comprises mist-mixing under emulsion forming conditions the oil and an alkali refining agent whereby the free fatty acids in the oil are neutralized to form a highly dispersed colloidal soap which acts to neutralize the electrical charges on colloidalimpurities in the oil, collecting the mist-mixture on a heated surface as a liquid emulsion and imparting a breaking temperature to the emulsion from said surface. and separating the soapstock from the oil, the refining agent being used in an amount suiliciently beyond that theoretically required to neutralize the free fatty acids in the oil so as to reduce the solubility of the electrically neutral impurities in the oil and to increase their solubility in water but insuiiicient to cause the formation of a two-layer soapstock.

34. The process according to claim 33 wherein the oil and reiining agent are merged prior to their mist-mixing but for an insufiicient period to permit major consumption of the refining agent to take place prior to the said mist-mixing.

RALPH H. FASH.

Patent No.' 2,511L2,oh2.`

CERTIFICAE 0F CORRECTION.

February 15, 191414. RALPH H. FASH.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page il, first column, line )4, for "sodlium" read --sodium; page 8, second co1- umn, line 5h', for "and" read as'; page 9, second column, line 17., for "sprays" read -spray; page 10, first column, line 26-2?, for "adpustable read adjustable; for heaated read -heated; page l2, first column, line l, claim l2, for "slght" Vread -slight; same column, line 6, claim l5, for "refining" read -rerefining; and that the' said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed end eeeled this 19th dey of December, A. D. 191414.

Leslie Frazer (Seal) Acting Commissioner of Patents.

page ll, second column, line 52, claim l0,

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