US2109130A - Process and apparatus for dewaxing oil - Google Patents

Description

Feb. 22, 1938; H. F. FISHER 2,109,130

' PROCESS AND APPARATUS FOR DEWAXING OIL I Filed May 25. 1935 2.Sheets-Sheet l" w T H aag' Feed 1 I I I I I i I i! z I j i IYZ S'h 1 t 01/ I I I |.u 674. j 4/ a. 5 h 1 5 18 L f fl 1 a INVENTOR. .Dewmred 017 War [2'32"122027 Z'Fzsher .Den mred 01'] J Ind Wash 017 ATTORNEY.

Feb. 22, 1938.

J. P G

H. F. FISHER PROCESS AND APPARATUS FOR DEWAXING OIL Filed May 25, 1935 2 Sheets-Shea 2 INVE NTOR. Harmon 1-." fisher A TTORNEY.

Fatented Feb. 22, 1938 pair-so stares aren't OFFICE Harmon F. Fisher, Los Angeles, Calif, assigncr to Union Gil Company of California, Los Angeies, Calif a corporation of California Application May 25, 1935, Serial No. 23,468

17 Claims.

This invention relates to the separation of wax from wax-bearing oil and relates more particularly to the electrical separation of suspensions of precipitated wax or similar materials from oil or oil solutions such as chilled lubricating oil or other waxy petroleum oils such as Diesel fuel oil.

When the temperature of lubricating oil containing wax or parafiin is sufiiciently lowered, the wax or paraffin is found to begin to solidify and [0 to be precipitated from solution in the form of a suspension of solids and as the temperature is further lowered more wax is precipitated until the oil and wax mixture finally congeals to a semi-plastic or even a solid mass. Oils containing a large quantity of wax will have relatively high congealing temperatures and oils containing a small quantity of wax will have correspondingly lower congealing temperatures. In the production of lubricating oils it is necessary to remove a large proportion of the wax or paraffin present therein in order to extend the lower range of temperature at which they will retain their lubricating qualities.

In general, present commercial methods of separating precipitated wax from wax-bearing oil such as cold settling, centrifuging, and filterpressing are time consuming, are involved with mechanical difi'lculties, are intermittent in operation and produce separated wax which contains such a large percentage of included 011 that it must be subsequently specially processed to avoid a prohibitive loss of oil.

It'is an object of this invention, therefore, to provide a method and apparatus capable of quickly and thoroughly removing precipitated wax from suspension in wax-bearing oil to obtain an oil relatively free from wax. It is another object of this invention to provide a method and apparatus capable of efflciently re- 40 moving the oil from the separated wax to produce a dry wax relatively free from included oil. It is also an object of this invention to provide a process and apparatus capable of continuous operation.

" These objects are attained in brief by causing the wax to be solidified or precipitated in the oil by chilling preferably in the presence of a diluent, and electrically treating the oil mixture containing the suspension of precipitated wax by to applying it in the form of a relatively thin film by any suitable meanssuch as'spouts, sprays or brushes, which are not necessarily associated with any electrical field or charge, to an electrode surface of extended area and then subjecting said oil 55 film on said electrode surface to the ionizing etfect of an intense ionizing electric field and/or an intense gaseous ion stream induced by an adjacent electrode of relatively small area maintained at an opposite electrical potential. This ionizing field partakes of the nature of a non-disruptive 5 electricaldischarge or a corona discharge from the adjacent electrode of small area through the intervening gas space to the electrode of extended area upon which the waxy-oil film is applied; Such electrical discharge phenomena appear to comprise an intense streaming of gaseous ions from the electrode of smallest'area to that of largest area, and it is to the effect of this gaseous ion stream upon the intervening waxy-oil film that the operation of this method is attributed. The flow of the gaseous ions from one electrode to the other under the influence of the high potential gradient is manifested by a phenomenon known as electrical windage and is herein referred to as an electrical windage. Hereinafter the term ionizing electric field shall mean a field of the character above described, and an ionizing electrode shall mean an electrode capable of producing such a field.

The efiect of the ionizing field upon the waxbearing oil film is to cause the suspended solid wax therein to deposit itself instantly upon the electrode surface in a solid compact and relatively tenacious thin layer and to adhere there while oil is forcibly separated and exuded therefrom in the form of beads or droplets of apparently greatly altered surface tension characteristics with respect to the wax. The droplets are caused to be removed from the thus deposited wax layer and the electrode surface carrying it, in part by coalescence and gravity run off, in part by being ejected into the space between the electrodes by electrical repulsion and in part by means of subsequently applied fluid washes.

The continued electrical treatment by the ionizing field of the deposited wax layer from which the oil has been initially electrically separated and/orfrom which it has been washed as stated hereinabove, results in further removal of residual included oil'and in producing a drier, more oil-free wax. It is an important feature of this invention, therefore, that the deposited wax can be so electrically treated by an ionizing electric field to produce a dry relatively oil-free wax.

Accordingly, therefore, one aspect of this invention, broadly stated, comprises subjecting a body of wax-bearing oil or similar oils containing suspended solid wax or the like to the effect of an ionizing electric field whereby the suspended wax is caused to be deposited upon an electrode under the influence of said electric field and whereby the wax is separated from the oil. Another broad aspect of the invention resides in the formation of the wax-bearing oil body or film upon the electrode on which the wax is to be deposited by means not necessarily associated with the electrical system, and without initial contact with an electrode of opposite polarity. Another aspect of the invention, broadly stated, comprises subjecting the deposited layer of wax to the continued effect of an ionizing electric field whereby it is compacted and included oil is expelled from the wax.

The invention also comprises jetting or washing the electrically. deposited wax layer, either prior to, during, or preceding electrical treatment by the ionizing electric field, with a suitable liquid or gas to remove included and adhering oil.

The invention also comprises apparatus for carrying out the process of the invention and includes forms of electrodes adapted to produce intense ionizing fields. These electrodes preferably are elongated and directed toward a cooperating electrode such as a depositing electrode surface.

The apparatus of the invention in its more speclflc aspects comprises an electrode surface or depositing electrode, means to apply a film of wax-bearing oil to said surface, and adjacent ionizing electrode means for subjecting the waxbearing oil film and deposited wax layer to an ionizing electric field. This phase of the invention also includes a liquid wash or gas jet to remove adhering and included oil from the deposited wax, and may further include a scraper or other means to remove the treated wax from the electrode.

Other objects, advantages and features of the invention will be evident hereinafter, and the invention further includes such other novel features and combinations of steps or parts and such other applications of the invention as may appear.

In the accompanying drawings, which illustrate various embodiments of the invention:

Fig. 1 is a sectional plan view of the treater, taken from line l-l of Fig. 2;

Fig. 2 is a sectional elevation view of the treater taken at section line-22 of Fig. 1;

Fig. 3 is a partial sectional elevation of the a type of ionizing electrode system; and

Fig. '1 is an optional spray or jetting system for the application of liquid to be treated.

The treater as illustrated in Figs. 1 and 2 is provided with a gas tight enclosure l0 containvided within the enclosure III by means of which the liquid to be treated such as wax-bearing oil rapidly distribute the applied wax-bearing oil.

While only two spouts and 81 are illustrated a greater number of spouts similarly positioned at successively lower elevations may be employed under certain conditions.

An optional means for applying liquid to be treated to the drum electrode [2 which may be substituted for the funnels 80 and 8| is illustrated in elevation in Fig. 7 and comprises a series of jetting or spray nozzles spaced one above the other at a suitable distance from the cylindrical surface. The spray nozzles are supported and connected to the liquid supply by means of manifolding 86 and supply pipe 81 which enters the treater enclosure ID at 88.

'Any other convenient method of application of the wax-bearing oil to the depositing electrode surface that will result in the formation of a uniform and satisfactory film or body thereon may be employed, for example dipping, brushing or flowing in a body.

Also contained within the treater enclosure 10 diametrically adjacent to and concentrically surrounding the cylindrical surface of the drum electrode are a plurality of ionizing electrode systems 50 as illustrated in Figs. 1, 2 and 3, or ionizing electrode systems 26 as illustrated in Figs. 4 and 5.

The ionizing electrode systems 50 as illustrated in Figs. 1, 2 and 3 are of the rod type and each comprises a plurality of slender, wire-like sharp pointed rod units 5| supported horizontally one above the other all in a plane common to the axis of the drum l2, by means of a bar upright 52. The pointed ends of the said rod electrode units are directed toward and are disposed adjacent to and spaced from the cylindrical drum surface I2 a suitable distance according to the applied voltages as specifled hereinafter. The bar uprights 52 are attached at their lower ends to an angle iron ring 40 which encircles the drum l2. The angle iron ring 40 is supported from the bottom l8 of the enclosure l0 and is electrically insulated from all of the other surrounding structures by means of several equally spaced insulators II.

The ionizing electrode systems 26 as illustrated in Figs. 4 and 5 are of the combination rod and ring type and each includes a plurality of units, each unit comprising a ring 32 and a coaxial rod electrode 36 directed toward drum surface l2. The ring electrodes 32 in all of the ring and rod types of electrodes are practically identical and are constructed with cross-sectional shapes which are convex with respect to the central coaxial rod electrodes. These ring electrodes are electrically connected to and supported from the bottom l8 of the enclosure I0 in groups one above the other by means of suitable metallic interconnections 33 and 34 and columns 35 as shown in Fig. 5. The central rod electrodes 36, in all of the ring and rod types of electrode systems 26 are supported in groups, one above the other and positioned with respect to the surface of the drum l2 in a manner similar to the hereinbefore described pointed rod type of electrodes 5| by means of bar aioaiso uprights 38 which are likewise attached at their lower ends to the supporting angle iron ring W. The rings 32 are positioned such that the pointed ends of the coaxial rods 36 extend just to or slightly beyond the plane of the edges of the rings nearest to the surface of the drum l2. Considerable variation on either side of this electrode position is allowable.

The electrode systems 26 and 58 are for convenience illustrated as comprising groups of three and five electrode units respectively, supported one above the other as shown in elevation in Figs. 3 and5, but greater numbers of electrode units may be so supported in each system for treaters of greater height and capacity.

,An optional form of ionizing electrode system is illustrated in elevation in Fig. 6 and comprises a serrated or notched thin metal sheet supported by means of bar upright 52 in the same position and space relationship with respect to the drum l2 as hereinbefore specified for the rod type of electrode system 59, illustrated in elevation in Fig. 5. The notched ionizing electrode systems 53 maybe substituted under some conditions for the rod type electrode systems Fill in the locations shown in Figs. 1 and 2.

Directly below the lower edge of the drum electrode i2 is positioned a trough or launder or semicircular .outline in plan which is divided into two sections 55 and 56 by means of a division plate Ell. These launders are adapted to catch treated liquid which runs down the outer cylindrical surface and drops from the loweredge of the drum. Troughs or launders 55 and 56 are provided with drain pipes 58 and 59 respectively, leading through sealed joints in the bottom it to gastight receivers or to other suitable means to maintain the enclosure Hi gas-tight and under pressure if desired.

A flexible scraper is supported along one edge by means of an upright dfl connected at its upper end to the top it of the enclosure. The scraper at is adapted to contact the length of the cylindrical surface of the rotating drum along its scraping edge 652. Between the ends of trough 55 and ill? and directly under the contacting edge of the scraperv 68 is positioned a funnel 6 adapted to catch the treated solids such as wax removed from the cylindrical surface of the drum 52 by said scraper 6B. A pipe 65 extends through a tight joint in the bottom I d of the enclosure for withdrawing the solids caught by the funnel 844 to a gas-tight receiver. I

Approximately on the diametrically opposite side of the drum l 2 from the funnel system d@di is provided a plurality of downwardly directed spray nozzles 6? which are directed toapply a liquid wash spray or jet of gas to the adjacent drum surface. A supply pipe 68 and branch manifolding 69 are provided for supplying wash liquid or gas to the spray nozzles and at the same time to supporting them.

The bar type of ionizing electrodes and the central electrode elements of the combination rlng-and-rcd type of ionizing electrodes are, in operation, maintained at a common high electric potential with respect to the surrounding ring electrodes 32 and with respect to the drum electrode l2 from a suitable source of high voltage direct current. Electrical connection is made between this source of electric potential and the said electrodes by means of conductor H which enters the top of the treater enclosure I! through a high potential lead-in insulator 12. The electrlcal connection common to all of the said electrodes is maintained from conductor ll through the metallic supporting ring M and uprights 52 or 38. The electrical return circuit is completed to the potential source W from the grounded drum l2 and from the ring electrodes 32 when they are optionally employed, through the body of the treater and the connecting conductor 53.

A valve is provided leading from the bottom it of the treater through which condensate, collected oil and diluent and wash oil spray can be expelled and by which internal gas pressure can be controlled.

The operation of the invention is as follows:

Oil containing wax in solution is chilled to a temperature at which wax is solidified or precipitated from solution and appears in the oil in theform of a suspension of solid or plastic wax particles. The thus chilled wax-bearing oil containing precipitated wax enters the treater under suitable pressure through supply pipes 82 and 83 and is introduced into the tops of funnels 8d and 86. The wax-bearing oil flows down to the ends of the contracted spout portions of the funnels 8d and 8! which conform closely, but with,

slight clearance, to the shape of the cylindrical drum surface, comes into contact with the cylindrical drum surface, and flows out through said slight clearance therebetween. Under the combined influence of gravity and rotation of the drum the thus applied wax-bearing oil forms a suitable film over the cylindrical surface extending continuously in the direction of rotation. The thus formed wax-bearing oil film is initially subjected to the intense ionizing field between the first of the ionizing electrode systems 50 and the drum surface, which efiects an immediate deposition of .the precipitated Wax in a thin dense layer upon the cylindrical surface of the drum electrode. with the simultaneous freeing of oil therefrom in the form of a multitude of small beads or droplets, a large portion of which,'in a short time, coalesce and under the iniluenceof gravity run down the waxsurface-and drop from the lower edge of the drum into the trough 55.-

As the drum continues through the initial rotation of 180 from the point of application of the Wax-bearing oil in the direction as indicated by the arrow, the deposited wax layer from which the oil has been partially freed is further treated by the intense ionizing fields from the following ionizing electrode systems 50 which comprise the initial treating group of electrodes. These fields act to complete the deposition of wax and to re move a large portion of the residual oil included in the deposited wax layer."This residual oil removed from the deposited wax layer also drains into the trough 55 and oil thus received in trough 55 is withdrawn from the treater through pipe 58. This oil which is completely dewaxed constitutes a major portion of that which is separable from the deposited wax.

' The deposited wax layer on the drum surface which has thus been initially treated under the influence of the first group of seven ionizing electrode systems 5c in the first 180 of rotation of the drum electrode 52 for the removal of residual included and adhering oil is subjected to a spray of wash oil such as cold liquid propane or other suitable light hydrocarbon from nozzles Bl. The thus applied wash, oil flows down the cylindrical surface of the rotating drum under the influence of gravity, carrying with it a. large portion of the adhering dewaxed oil film and at the same time at this point where the deposited wax layer is not subjected to an intense electric field,

a portion of the thus applied wash oil penetrates or soaks into the deposited wax layer. This penetration allows the wash oil to reach and dilute the includedoil.

Other convenient means for applying a liquid wash at this point, such as spouts similar to those for the application of the wax-bearing oil to the drum surface, may be optionally employed.

Instead of employing a liquid wash, gas, such as propane or ethane may be supplied to the nozzles 61 under pressure to form gas jets which by reason of their downwardly directed impingement upon the deposited wax surface on the drum, effect a coalescence and downward sweeping of the dewaxed oil droplets and adhering oil film from the said surface and into the trough 56.

The thus washed deposited wax upon further continuation of rotation of the drum electrode, is again subjected to intense ionizing fields from the remaining electrode systems 50 in the following approximately 90 of rotation subsequent to the washing process, which effects the removal from the wax of a large portion of remaining included and adhering dewaxed oil together in solution with the applied wash oil, which then coalesces and runs from the lower edge of the drum into the trough or launder 56 from which it is withdrawn through pipe 59. Finally the thus washed and electrically deoiled deposited wax layer is removed from the rotating drum surface by the scraper 60. The wax removed by scraper 60 falls into the funnel 64 from which it is removed through outlet 65. The drum surface from which the wax has been removed by the scraper upon further rotation receives another application of wax-bearing oil from the funnels 80 and 8| and the cycle just described is repeated.

It has been discovered that the efiiciency and thoroughness of electrical dewaxing according to this invention increases with increased applied potential. At applied potentials approaching 60,000 volts or more, it is found that the pointed rod types of electrode systems 50 as illustrated in elevation in Fig. 3, or the notched sheet metal electrodes as illustrated in Fig. 6, are effective for efiicient and thorough electrical dewaxing.

Electrode units of the ring and rod type employing rings 32 as illustrated in elevation in Fig. 5, are particularly desirable where the available applied electric potentials are limited. It has been found that for potentials of approximately 30,000 voltspr less that the most efiective ionizing field is obtained with these electrode combinations employing the said ring electrodes 32. It is to be noted that where a surrounding ring electrode 32 is employed there are two ionizing fields, one between the central electrode 36 and the surrounding ring 32 and the other between the pointed end of the central electrode and the drum surface l2. With the plain rod types of electrodes illustrated in elevation in Fig. 3 employing no surrounding ring'electrode, the ionizing electric field is maintained between the pointed end thereof and the cylindrical surface of the drum electrode only.

Thus with applied potentials of 60,000 volts or more, electrode systems of the type illustrated in Fig. 3 may be placed surrounding the drum electrode as shown in Figs. 1 and 2. With applied potentials ranging around 30,000 volts or less, the electrode systems of the type illustrated in Figs. 4 and 5 are most effective and may be placed surrounding the electrode as shown in Fig. 4, displacing the electrode systems 50 of Fig. 1 and with this arrangement satisfactbry dewaxing respect to the drum surface.

her of electrodes have been shown. However, in

practical operation it has been found advantageous to completely surround the drum electrode l2 except at the intervals where space is necessarily occupied by the washing spray nozzles 61 and the scraper apparatus 60, with electrodes set as closely together as the available space will permit, but with the limitation, however, that in general the greatest efiiciency of treatment has been obtained where the electrodes have not been placed closer circumferentially about the drum electrode than the vertical or longitudinal distance between the individual points thereof. For example whenemploying a potential difierence between the electrodes and the drum of 60,000 volts 'and when employing the plain pointed rod type of electrodes as illustrated in Fig. 3, an optimum circumferential spacing between the points of the electrodes has been found to be approximately 4 inches. The optimum arrangement of pointed electrodes therefore, for this voltage, is one in which they completely surround the available cylindrical surface of the drum electrode on four inch centers, both circumferentially and longitudinally with It has been observed that the ion stream fiows from the end of the pointed electrode in a spray-like diverging stream to the cylindrical surface of the drum electrode, forming by impingement thereon a circular pattern which has a given effective diameter for each given combination. of electrode separation and spacing suited to a. given impressed potential difference. Under the conditions above mentioned, at a potential difference of 66,000 volts under which conditions the pointed electrode unit is just spaced sufficiently far from the cylindrical electrode to prevent spark-over, the diverging ion stream from the end of the said pointed electrode forms a circular pattern upon the cylindrical electrode surface having a diameter of approximately 4 inches. Most emcient spacing of these electrodes, therefore, is one where these patterns formed by the impingement of the ion streams approach tangency to one another, thus under the conditions just} stated, the best electrode spacing is four inches on centers and under these conditions all parts of the cylindrical surface of the drum electrode when it is rotated are contacted by the ion streams. Under the above conditions an electrode spacing of less than four inches results in decreased treating effectiveness which is apparently due to mutual interference of the adjacent electric fields or ion streams.

From the foregoing, it will be observed that.

the ionizing electrode units may be of two general types, one in the form of a pointed or notched sheet of thin metal or a pointed metal rod only, and the other in the form of a pointed rod surrounded by a coaxial ring. In the case of the plain rod type the ionizing electrode comprising a pointed rod is positioned with its pointed end change to precipitate the stearin, and the subsequent separation of the stearin and the thus treated cottonseed oil accomplished electrically according to the process described herein for the separation of wax from oil. A low cold test cottonseed oil is thus produced.

Other oils which may be so treated for the separation of the herein enumerated fats and fatty acids are sperm oil, oleo oil, lard oil, soy bean oil, etc.

The foregoing is merely illustrative of an operative apparatus and process, and the invention is not limited thereby but may include any process and apparatus which accomplishes the same result within the scope of the invention.

I claim:

1. A process for removing suspended matter from oleaginous liquids which comprises applying a film of said liquid to the surface of a depositing electrode of extended area and establishing an electric field between said depositing electrode and a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of liquid and directed toward the surface of said depositing electrode and said electric field being of sufiicient intensity to deposit suspended matter in said film of liquid on said depositing electrode, and depositing said matter in a layer on said depositing electrode surface under the influence of said field.

2. A process according to claim 1 in which said electrode of relatively small area is substantially rod shaped and with its longitudinal axis directed toward the depositing electrode and in which said electric field is of sufficient intensity to produce an electric windage impinging upon said film of liquid on said depositing electrode.

3. A process for removing suspended wax from wax-oil mixtures which comprises applying a film of said wax-oil mixture to the surface of a depositing electrode of extended area and establishing an electric field between said depositing electrode and a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of oil and directed toward the surface of said depositing electrode and said electric field being of suillcient intensity to deposit suspended wax in said wax-oil mixture on said depositing electrode and depositing said suspended wax in a layer on said depositing electrode surface under .the influence of saidelectric v tric field between said depositing electrode and a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of oil and directed toward the surface of said depositing electrode and said electric field being of sufiicient intensity to deposit the suspended asphaltic bodies in said film of oil on said depositing electrode and depositing said asphaltic bodies in a layer on said depositing electrode surface under the influence of said electric field.

5. A process according to claim 4 in which said suspended matter is asphalt.

effective electric field, establishing an electric field between said depositing electrode and a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of liquid and directed toward the surface of said depositing electrode, moving said applied film of liquid into the effective electric field, said electric field being of sufiicient intensity to deposit the suspended matter in said film of liquid on said depositing electrode, and depositing said suspended matter in a layer upon said depositing electrode surface.

8. A process for removing suspended wax from oil which comprises establishing an electric field between a depositing electrode of extended area and a second electrode of relatively small area as compared with said depositing electrode, applying a film of said wax bearing oil to the surface of said depositing electrode out of the effective electric field, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of wax bearing oil, said electric field being of sufiicient intensity to deposit suspended wax in said film of oil'on said depositing electrode, moving said applied film into said electric field, and thereby depositing trade of relatively small area as compared with said depositing electrode, applying a film of said liquid to the surface of said depositing electrode out of the efiective electric field, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of liquid and said electric field being of sufficient intensity to deposit suspended matter in said film of liquid on said depositing electrode, subjecting said applied film to said electric field, and thereby depositing said suspended matter in a layer upon said depositing electrode surface.

10. A process for removing suspended wax from oils which comprises applying a film of said 011 to the surface of a depositing electrode of extended area, and establishing an electric field between said depositing electrode and a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of liquid and directed toward the surface of said depositing electrode, said electric field being of sufilcient intensity to deposit wax from said film of oil on said depositing electrode surface in a layer, removing from the thus deposited wax layer a major portion of the oil from which the wax was deposited and washing said deposited wax,

to the influence of an electric field to remove residual oil from said wax.

11. A process for removing suspended wax from wax-bearing oils which comprises applying a film of said wax-bearing oil to the surface of a depositing electrode of extended area, establishing a plurality of electric fields of sumcient intensity to deposit suspended wax in said film between said depositing electrode and a plurality of electrodes of relatively small area as compared with said depositing electrode, said electrodes of relatively small area being substantially surrounded by a gaseous medium and spaced from said film of liquid and directed toward the surface of said depositing electrode and moving said depositing electrode surface carrying said oil film through said electric fields whereby suspended wax in said film of oil is deposited on said depositing electrode surface.

12. A process for removing suspended wax from wax-bearing oils which comprises applying a film of said wax-bearing oil to the surface of a depositing electrode of extended area and establishing 13. A process for removing suspended wax from wax-bearing oils which comprises applying a film of said wax-bearing oil to the surface of a depositing electrode of extended area and establishing a unidirectional electric field between said depositing electrode and a second electrode of relatively-small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of liquid and directed toward the surface of said depositing electrode and said unidirectional electric field being of suflicient intensity to deposit suspended wax in said wax-bearing oil on said depositing electrode and depositing said wax in a layer on said depositing electrode surface under the influence of said unidirectional electric field.

14. A process for removing suspended wax from oil which'comprises subjecting the oil containing suspended wax to the influence of an electric field and depositing the suspended wax in a layer upon an electrode surface and removing said depositedlayer from the major portion of the oil from which it is deposited, subjecting said removed deposited wax layer on said electrode surface to a washing with a quantity of wash solvent while said layer is substantially free from the effective influence of an electric field, subsequently subjecting the washed wax layer to the influence of an efiective electric field from a second electrode of relatively small area as compared with said depositing electrode, said second electrode being substantially surrounded by a gaseous medium and spaced from said film of wax and directed toward the surface of said depositing electrode, separating oil from said washed wax under the influence of the last named field and removing the thus treated wax layer from said electrode surface.

15. Apparatus for removing precipitated mat:- ter from liquids comprising a container, a plurality of pointed electrodes spaced from the container and substantially surrounded by a gaseous atmosphere, a depositing electrode surface of extended area spaced axially from the pointed electrodes and disposed substantially perpendicular thereto, means for applying a film of liquid containing precipitated matter to said depositing electrode surface, means for establishing an electric field of suificient intensity to deposit precipitated matter. in said film of liquid on said depositing electrode and means for removing deposited matter from said depositing electrode surface.

16. Apparatus according to claim 15 with means to apply a fluid wash to said depositing electrode surface, and means to remove liquid from which precipitated matter has been re-' I moved and the fluid wash in separate streams.

17. Apparatus for removing precipitated matter from liquids comprising a container, a drumshaped depositing electrode surface inside of said container, a plurality of pointed electrodes in said container substantially surrounded by a gaseous atmosphere, and spaced from and substantially radially directed toward said drumshaped depositing electrode surface, means to apply a film of liquid containing precipitated matter to said depositing electrode surface, means for establishing an electric field of sumcient intensity to deposit precipitated matter in said film of liquid on said depositing electrode and means for removing deposited matter from said depositing, electrode, surface.

Harmon F. msnm.

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