US2300283A

US2300283A - Process and apparatus for dewaxing oil

Info

Publication number: US2300283A
Application number: US191682A
Authority: US
Inventors: Harmon F Fisher
Original assignee: Union Oil Company of California
Current assignee: Union Oil Company of California
Priority date: 1938-02-21
Filing date: 1938-02-21
Publication date: 1942-10-27
Anticipated expiration: 1959-10-27

Description

Oct- 27, 1942- A H. F. FISHER .A 2,300,283

PRQcEss AND APPARATUS FORADEWAXING OIL Filed Feb.' 21, 1938 4 sheets-sheet 1 n@ k/f A ATTURNEY.

Oct. 27, 1942. H` F. FlsvHER 2,300,283

PROCESS AND APPARATUS FOR -DEWAXNG OIL Filed Feb. 21, 1958 4 snets-sheef 2' IVN VEA! TOR. Ha rmozz E'Fzls'her BY AmRNEY.

Oct. 27, 1942t H. F. FISHER.

PROCESS AND APPARATUS FOR DEWXING OIL Filed Feb. 2l, 1938 4 Sheets-Sheet 3 H.'F'. FISHER PROCESS AND APPARATUS FOR DEWAXING OIL Filed Feb. 2l, 1.938- 4 Sheets-Sheet 4 mls/151mm-y Harmon .F.'Fzsher BY 77 Ammvmf.

Patented Oct. 27, 1942 PRocEss AND ArPAiTUs Fon nEwAXnvG .Harmon F. Fisher, Los Angeles, Calif., assigner to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application February 21, 1938, Serial No. 191,682

20 Claims.. (Cl. 204-184) This invention relates to the separation of precipitates, such as wax, asphalt, resin and the like substances, from oils and particularly to the electrical separation of hydrocarbon oils from the waxes which they contain to produce relatively oil free, high melting point waxes and low pour point oils.

Many oils, such as lubricating oil, fuel oil, mo-

tor fuel and other similar oils, which are derived from crude oils contain parainic, waxy, asphaltic and resinous constituents which may appear by reason of having been present in the crude oil formation from which such oils were derived, or by reason of their formation in intermediate treating processes, such as distillation or cracking. The wax-like constituents which may thus be present limit the minimum temperature at which these oils can be used by their solidifying or congealing at low temperatures. The asphaltic' or resinous bodies are also objectionable for numerous other reasons well known in the art of lubricating oil and motor fuel rening. Therefore, in the rening of such oils it is common practice to remove a substantial proportion of these waxy or asphaltic and. resinous constituents in order to lower the pour point and improve the quality of such oils.

The separation of the undesirable parainic v and waxy bodies from oil fractions has been accomplished in `the p'ast by several processes, the most common and oldest of which are the cold settling and cold-pressing fprocesses. These processes have been `inefllcient, time consuming, mechanicallyinvolvedfand unsuited to the separation of quickly -cooled or ash chilled waxy vconstituents from oil and have heretofore produced separated constituents having a high percentage of oil contamination.

AsphaltlqA resinous and tarry constituents and color bodies vhave been separated-by well known processes employing acid, alkali, clay and other chemical treatment and recently by solvents. In the solvent processes the oil containing the' undesirable constituents, such as asphalt, resin, color bodies and the like, is dissolved in a quantity oi' a suitable diluent, such as liquid propane or other liquid normallyl gaseousV hydrocarbons, which has preferably at normal temperature a low solvent power' for these bodies while at the same time retaining substantial solvent power for the desirable fractions of oil. Such solvent treatmay be separated from the oil solution by settling in a reasonable length of time.` In this solvent process, however, not only a quantity of the precipitated material remains in the oil solution in the form of an unsettled finely divided suspension to cause serious contamination of the nal oil product unless special steps are taken for the complete removal, but the separated insoluble precipitate also still contains a high per centage of the oil from which it is desired to separate it.

Objects of this invention are to obvi'ate the disadvantages of the heretofore employed processes for the separation of the said waxy, parafiinic, asphaltic, tarry, resinous and color bodies from oleaginous liquids and to provide an improved process for the separation of these substances from such liquids which is emcient, eco-- i arated constituents, such as Wax, Will be more ment results in the rejection of asphaltic bodies Y from the oil diluent solution in the form of a relatively heavy insoluble precipitate or as a Aheavy thoroughly deoiled and thus freer from contamination by oily constituents, than has heretofore been possible. Another object is to provide a process which accomplishes an improved percentage of recovery of the oleaginous liquids from the separated constituents Aresulting in a larger unit yield of such separated liquids.

For convenience the process and apparatus of this invention will be hereinafter largely referred to the separation of wax from oil.

The objects of this invention are attained, in brief,'by causing the wax to be solidified or precipitated in the oil by any suitable method, such as by chilling, preferably in the presence of a diluent, and electrically treating the wax-bearing oil mixture containing the solidified wax by applying the mixture in the form of a relatively thin film to an electrode surface of extended area and then subjecting said oil .film while on said electrode surface to the effect 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 electric eld partakes of thel nature of a non-disruptive electrical Idischarge 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 lm is applied. .Such

electrical discharge phenomena appear to comf prise an intense streaming of gaseous ions from liquid phase, a substantial proportion of which 55 the electrode oi smallest area to that of the largest area, and it is to the effect of this gaseous ion stream impinging upon the intervening waxoil film that the operation of this method is attributed. Hereinafter, the term ionizing electric field shall mean a eld of the character above described and an ionizing electrode shall mean an electrode capable of producing such a eld.

The effect of the ionizing field upon the waxbearing oil film is to cause the suspended solidified waxtherein to be deposited or plated instantly upon the electrode surface in a solid;I 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. droplets of oil thus separated are caused to be removed from the thus deposited wax layer and the electrode surface carrying it, by coalescence and gravity run ofi', or preferably by means of subsequently applied fiuid washes and mechanical wiping operations.

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

Accordingly, therefore, one aspect of this invention, broadly stated, comprises subjecting a The.

body .of wax-bearing oil or similar oils containing suspended solid wax or ythe 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 eld and whereby the wax is separated from the oil. Another aspect of the invention, broadly stated, comprises subjecting .the deposited layer of wax tothe continued effect of an ionizing electric field whereby it is compacted and the occluded oil is expelled from the wax.

The invention also comprises jetting, washing or scrubbing the electrically deposited wax layer either prior to, during or subsequent to electrical treatment by the ionizing electric field, with a suitable liquid and wiping the thus treated wax layer to remove occluded and adhering oil.

Accordingly, the invention resides more specifically in an improved process and apparatus for the electrodeposition of the suspended precipitate from oils wherein the oil precipitate mixture, preferably in the presence of a diluent, is placed in the form of a relatively thin layerl upon a horizontal drum typeJ electrode and subjected there to an intense ionizing electric field whereby the precipitate is deposited and held in a dense layer upon the moving drum electrode surface, thus effecting the separation of a major portion of the oil from the precipitate and whereby the precipitate layer thus separated from. the oil may be subsequently thoroughly washed and further electrically treated to remove occluded and vadhering oil to produce a relatively oil free precipitate and a maximum recovery of purified oil. The

invention also resides in the process and ap' cipitate at a plurality of points and in the recycling and introduction of a portion of the wash oil to the oil feed prior to the precipitation step and the electrodeposition of the resultant suspended materials.

Another aspect of the invention resides in subjecting the wax which has been electrically deposited in a thin layer upon the electrode surface to wiping or scraping at a plurali-ty of points to remove occluded oil and wash oil and, if desired, a portion of the soft superficial layer of the deposited wax layer whereby the remaining portion of the deposited Wax will be of a high density and relatively free from occluded oil and whereby the removed oil and soft wax may be recycled to the wash jets and/or to the wax-bearing oil feed for further treatment.

This yprocess is particularly adapted and finds one of its major industrial applications to processes for the separation of waxes from lubricating oil to produce high pour point oils relatively free from wax and high melting point waxes relatively free from oil. It is a particular advantage of .the process that in contradistinction to processes of settling, centrifuging or filtering, a careful preparation .of the wax 4precipitate as to crystal structure or plasticity, is unnecessary and avoided. In fact, all that is required is to separate the wax as a solid phase by chilling or otherwise precipitating it by reducing the solubility of the wax in the solvent or oil. I have found that :the process works particularly well with flash chilled waxes, that is, .those waxes formed byl such rapid chilling that the waxis in a very finely divided condition and usually difficult to separate by other methods heretofore employed.

Other objects, advantages and novel features of :the invention will be evident hereafter.

In the accompanying drawings, which illustrate preferred embodiments of the invention with which the process of this invention may be performed, Fig. 1 is a typical cross-section of the Fig. 3 is an enlarged detail of a portion of one of the ionizing electrode supporting segments.

Fig. 4 is a fragmentary detail in partial section of the removed lower right end portion of the treater of Fig. 2 showing the stuffing boxes for the various wiper, scraper and liquid gathering mechanisms shown in sections in the lower portion of Fig. 1.

5 is a fragmentary right end view of that portion of the treater sho'wn in Fig. 4.

Fig. 6 is a typical cross-section of an optional arrangement of the electric treater.

Fig. 7 is an open end elevation of the optional arrangement of the electric treater as .viewed from line 1-1 in Fig. 8 with the treaterhe'ad removed. i

Fig. 8 is a side sectional elevation of the optional arrangement of the electric treater.

Figs. 9 and 10 are fragmentary7 details of anv u'pper and lower portion, respectively, of the paratus wherein the electrically deposited prewhich the controls and piping for the various jets, wipers and wax sera/pers extend.

Fig. 11 is a typical enlarged fragmentary detail of anumber of the pointed ionizing electrodes and a supporting segment; and

Fig. 12 is a fragmentary side view partly in section of a pair of the rotating drum electrode supporting rollers and drive shaft.

xed to a shaft I6 which -is 'in turn rotatably `supported on bearings I1 and I8 located at vthe apex of supporting A frames I9 and 2Il, respec tively. These A frames I9 and 20 are invturn supported by an I beam 2I and bracket 22, respectively, connected at their ends in a suitable manner, such as by welding, to the permanent portions of the bumped heads of the treater container surrounding the removable head I3. -A worm gear 25, keyed to the shaft I6 and meshing with a worm pinion 26 which is in turn driven by the motor M through the reduction gear 21 and shaft 28, serves to rotate the said drum I5. The said shaft 28 passes laterally out of the treater container through a stuing box 30 attached to the curved portion of the bumped head of the treater container. Spaced intermediate the outside surface of the drum I and the inside surface of the container I0 are a plurality of circular ionizing electrode supporting segments 3l, as best shown in Figs. 1 and 2 and in the enlarged detail of Fig. 3, carrying a large number of spaced ionizing electrode points 32. The pointed ionizing electrodes 32 are thus supported through the container wall and through flanges 58 which close the outer ends ofthe anged nipples 5,9. The said nozzles 55 are positioned and supported centrally within the open sections 60, provided through the ionizing electrode supporting cage structure at suitable intervals said open sections being formed by omitting portions of certain of the supporting Vsegments 3l.

n F are iets provided for spraying wash liquid Vunen the surface of the drum I5 and they are spaced at suitable intervals along the length' of the container I0. As in the case of the nozzles 55 suitable openings are provided through' the ionizing electrode cage structure by omitting portions of the segments 3| to allow the sprays of wash liquid from the side jets A to F to reach and impinge upon the surface lof said drum I5. The jets A to Fare supplied with wash liquid by means of suitable manifolding pipes, as shown at 62 in Figure 2.

W1, W2 and Wa are wipers for the purpose of removing liquid films and/or soft Wax from the drum surface. Each comprises a shaft, such as shown at 64, extending the length of the adjacent to and directed substantially radially toward the outside surface of the drum I5, as shown. The ionizing electrode segments 3lV are supported at their ends by the longitudinal rods 34 and are uniformly spaced vthereon by means of tubular spacers 35. The ionizing electrode assembly thus built up of the plurality of segments 3| upon the rods 34 forms a cage-like structure the whole of which is supported at 31, 38 and 39 by means of the insulators 4I, 42 and 43, respectively, which are in turn attached to the anges- 45, 46 and 41, respectively. The insulators 4I,l 42 and 43 thus, as. shown on the drawings, extend through the treater container walls and into the cylindrical recesses 49, 5I) and 5I which are closed by the said flanges 45-41 whereby the size of the container I0 may be a.

minimum necessary to provide adequate, spacing from the ionizing electrode cage structure without having to provide additional clearance of the insulators.

Electrical connection is made from a suitable source of high voltage unidirectional current to the ionizing electrode cage assembly through the lead-in insulator 52 and conductors 53 and 54. The electrical connection of opposite polarity to that of the ionizing electrodes is completed from the depositing electrode drum I 5 through the treater structure and the ground or other suittainer. Thusthe high potential unidirectional electric field may be maintained between the ionizing electrode points 32 -and the outer -surface of the depositing electrode drum I5.

A-plurality of ared triangular shaped nozzles 55 are supported adjacent one another along the length of the surface.of the drum I5- and serve to apply the wax-bearing oil mixture to be treated upon the rotating drum surfacein the form of a wide layer of uniform thickness. These nozzles 55 are supplied with the wax-bearing oil mixture-by means of a manifold 56 and the interconnecting branch pipes 51 'which extend vable conductors connected to the treater conwith the moving surface of the drum I5 andthe contact pressure between said feit on 'the wipers and drum surface is maintained by torsion applied to their shafts by means of suitable weights, as shown at 68, attached to the ends of cranks, such as 69, which in turn are attached to the exposed end of the shafts which extend through suitable stuling boxes, such as that shown at 1IJ, in the curved portion of the bumped head of the treater container. All of the wipers are similarly controlled.

G is a treated liquid gathering device comprisinga pipe 15 extending along the length of the treater container and slotted along the upper edge portion thereof which is adjacent to the drum surface. .As in the case of the Wipers, W1-W3, .the liquid collecting pipe 15 carries a metal blade 16falong the edge of which is attached a strip of felt which makes light contact with the moving drum surface. Another metal strip 11 parallel with and adjacent to 16 is provided along the opposite side of the slot in the pipe 15 and serves to prevent any liquid,- other than that removed by the wiper felt, from entering the pipe 15. Also, as in the case of the wipers, W1W3, the liquid removing device G, and its associated blade 16 and felt strip, is maintained in contact with the drum surface by means of torsion applied to-the end of the pipe 15 which extends through the bumped head of the treater container at the stuing box 18. The torsion is applied by means of weight 19 acting throughcrank 80. The angle of the jets F may be similarly adjusted by rotationof the manifoldpipes to which they are connected, the typical arrangement of which is best shown at 82 in Fig. 4. The said manifold pipe 82 extends through the length of the treater shell and out through the stuiiing box 83 and issupported at the opposite end in a suitable socket, not shown,

The wipers Wi-Wa, thel jets F and the liquid collector G may each be withdrawn intact from the treater through the head by removing the flanges to which their respective manifold pipe stufling boxes are attached. -A typical arrangement of these stuning boxes and flanges is best shown in Figs. 4 and 5. These said apparatus assemblies may thus be readily removed from the container for adjustment, renewal or repair without otherwise opening the treater container and thus with a minimum of labor and lost time.

Si and S2 yare wax removing

Scrapers comprising shafts

85 and 86 extending through the length of the treater and carrying sharp edged metal blades 81 and 88, respectively, bearing upon the length of the drum surface. The sharp edges of the metal scraper blades 81 and 88 are pressed with considerable force against the drum surface by means of torsion applied to their

shafts

85 and 86 by'means of cranks 90 and 9| and the attached

Weights

92 and 93, respectively. The cranks 90 and 9| and

weights

92 and 93 act upon the outwardly extending ends of the

shafts

85 and 86 where they pass through stuing boxes in the bumped heads of the treater shell, as best shown in Fig. 5.

A wax screw 96 extends throughout the length of the bottom of the treater shell and in the` bottom of the trough 91 and is rotationally supported at bearings 98 and 99 and rotated by means of shaft which passes; through a stuffing box |0| by meansof the attached sprocket |02 The said Wax screw 96 extends from the scraper Si and S2 is subjected to the high potential ionizing electric elds from the adjacent pointed ionizing electrodes surrounding that portion of the treater drum with the result that oil occluded and entrained in the deposited wax layer `is sweated to the outer surface thereof.

The deposited wax layer while being subjected' to this said continued electric treatment may be subjected to a number of washing or scrubbing operations before being removed by the scrapers Si and S2, the washing liquid being introduced through any of the plurality of systems of jets A to'F, as desired, and for the purpose of best removing the sweated oil from the surface of the wax layer.

For example, a preferred nethod is to subject the deposited wax layer to vigorous washing or scrubbing by means of hard sprays of wash diluent from jet systems A, B andF. Jet system A has been found to be of particular importance in serving to dilute the waxy oil film which adheres to and is carried over with the rotation of the l drum upon the deposited wax layer surface and treater shell, as best shown in Fig. 2, into the upper portion of a wax collecting chamber |05. The said wax-collecting chamber. |05 is provided with a heating coil |06, a bottom outletl |01 and a vapor vent |08. l

The treater shell I0 is provided with a wash liquid outlet connection ||0 at the bottom.

The operation of the apparatus is as follows: Wax-bearing oil containing solidified wax in,sus pension, the wax having been precipitated by some method, such as chilling to a temperature below the normal cloud point or pour point of the oil together with a suitable diluent if desired, is introduced into the treater through the manifold pipe- 62, thence through the branch pipes 51 and is applied in a wide, relatively thin layer over substantially the entire width of the rotating drum electrode surface I5 by-means of the series of flared nozzles 55. D uringjzhe application of the wax-bearing 'oil in this manner the drum I5 is rotated in a counteiclockwise direction, as viewed in Fig. 1, and asindicated by the arrow 23. The thus applied wax-bearing oil layer flows downwardly under the force of gravity-over the electrode drum surface toward the liquid collector G and countercurrent to the upward movement of the rotating drum surface, during which time it is subjected to high potential ionizing electric elds from the points of the adjacent ionizing electrodes. The high potential ionizing electric elds in this area below the point of application of the nozzles causes an immediate electrodeposition of the solidified wax from the downwardly flowing oil film upon the upward moving drum surface in the form of a dense, relatively thin layer and this deposited wax is eventually carried with the rotation of the drum to the scrapers Si and S2 where it is forcefully removed and allowed to drop on the wax screw 98 in the bottom of the trough 91, and then carried thereby out of the treater container and into the wax collecting chamber |05 where it is subjected to the heat introduced through coil |06 and finally withdrawn as a liquid at |01. The evaporated dluent when it is employed in the process is vented from the wax collector chamber at |08. The said deposited wax layer intermediate the point of deposition below the waxy-oil application nozzles 55 and the said wax it is important to supply a suicient quantityof wash diluent through the jets A to carry the thus diluted waxy oil downward countercurrent to the movement of the drum surface toward the points of application of the wax-bearing oil feed whereby it commingles with the saidv applied wax-bearing oil and continues downward to the treated liquid collector G. 'I'he oil which is carried on over the top of the drum past the point of impingement of the jets A is thus reduced in amount and greatly diluted which is important in reducing the amount of oil removed with the deposited wax and hence is important in increasing the over-all recovery of dewaxed oil from the separated wax.

'Ihe wiper W1 has also been found useful in reducing the carryover of adhering oil with the rotation of the drum by acting as a dam against which the oil which is wiped from the wax surface by the felt strip 66 builds up to sufficient depth to force it to run back down the slope of the drum against the rotation thereof and to be finally collected together with the balance of the dewaxed oil in the liquid collector G.

'I'hus the deposited wax which is carried by the rotation of the drum past the jets A and wiper W1 is relatively free from adhering oil or, in other words, has a relatively dry surface. Upon continuing with the rotation of the drum between the wiper W1 and the point of impingement of the jets F the thus dried deposited wax layer is subjected to a continued ionizing electric field from the adjacent pointed ionizing electrodes which causes additional occluded oil to sweat" from the wax layer and to appear on its surface in a thin film or in the Aform of minute droplets.

By the application of a suilicient quantity of wash liquid to the thus sweated wax layer by means of jets B the oil which is drawn to the surface of the deposited wax layer by the electric eld may be washed away and withdrawn from the wax layer and the drum surface by means of the wiper W2 and the thus removed wash solvent and removed oil drops from the wiper We to the bottom of the treater container and is finally removed therefrom through the outlet connection H0. The thus treated deposited wax layer after it passes over the wiper W2 is advantageously subjected to another Vigr crous washing by means of a spray of wash solvent from the jets F for the purpose of removing any remanant of the adhering'oil which has -been sweated fromthe deposited wax layer and which has passed by the wiper W2 or that which has been subsequently removed by the continued electric treatment. The thus washed wax llayer is nally dried by the action of the Wiper W3 and immediately thereafter removed from the drum surface by means of the scrapers Si-Sz, as before described. The wax thus removed from the depositing electrode surface and which is conveyed from the treater container by means of the wax screw 96 is then a substantially dried wax and F only, additional scrubbing may be effectedA by employing additional Wash jets C, D and E. The additional Wash jets are particularly-effeotive when treating a' heavy lubricating oil which is somewhat more difficult to remove from the deposited wax than the lighter oils. The alternate subjection of the deposited wax "as it moves with the rotating drum surface rs'tto ionizing electric fields to sweat the occluded oil to the surface and then subjecting it to a hard spray of Wash solvent, results in a more oil free recovered Wax.

The scraper W2 may be made to bear against the deposited wax layer upon the moving depositing electrode surface by means of application of torsion to the lshaft to which it is attached suicient to actually, remove the supercial layer of soft spongy wax when it is present leaving only the hard dense underlying portion of the wax to continue with the rotation of the drum to be subjected to the wash spray issuing l' from nozzles F and to be finally removed by the v scrapers S1 and S2. The soft Wax when removed by the wiper W2 is aided in its removal from the Wiper surface'by means of the added ushing action of the added wash solvent applied by jets D and the thus removed soft wax drops to the bottom of the treater container and is withdrawn therefrom along with the wash oil through the outlet ||0, as before described.

The Wash liquid which is Withdrawn from the bottom of the treater through 'the outlet 'H0 may be recycled to any one or all of the wash solvent jets A-F and recycled at any desired rate necessary to maintain the desired ow of wash solvent and the desired force of sprays impinging upon the deposited wax layer on the drum surface. ||0 may also be pumped to the flash chamber and utilized as a portion of the diluent for the waxy-oil feed or the wash solvent thusV removed at ||0 may be split and a portion of it recycled to the wash spravs Aand another portion of it pumped to the said waxy-oil feed flash chamber, all as described and best shown' in Fig. 3 of my co-pending application, Serial No. 119,998. When the wash solvent removed at I I 0-from the treater is employed as a diluent for the waxy-oil feed the fresh diluent is preferably introduced into the system through one or anycf the Wash Sprays.

The wash solvent removed at' fore described treater container supports |24 and |25. The said semi-circular structure comprises l. an upper deck |69 extending throughout the As stated hereinbefore, an optional arrangel ment of the electrical dewaxing apparatus of this invention is shown. in Figs. 6 to 12 and comprises: A gastight container |20 having a flanged bumped head |2I, xed bumped head |22 and removable flanged' manhole |23. The'whole being-supported by the Webbed supporting structures |24 and |25. An open ended cylindrical depositing electrode |21 is co-axially and rotatably/,supported within treater container |20 by means of rollers |28|3| which are in turn supported upon suitable bearings carried by said supports |24' and |25, as shown at |33 and |34 in Fig. 12. One or both pairs of the rollers may be connected together by means of a suitable shaft, as shown at |35, which passes through a gas tight tunnel enclosure |32 and extends from the head of the treater container through the stuing boxes |36. The shaft |35 is driven through a suitable gear reduction unit |31 by means o f the motor |38. Power is thus applied through the supporting rollers to eifect rotation ofthe depositing electrode cylinder |21 which freely rests upon them.

Inside of the depositing electrode drum are a plurality of pointed ionizing electrodes directed toward the inside surface thereof and supported upon a plurality of circular segments, as

shown at |50, in a manner similar to those in Fig. 1, hereinbefore described. These pointed electrodes thus supported on the circular segments form a semi-cylindrical cage-like structure. y,tied together with a plurality of longitudinal tie rods |5| extending substantially through the length of the inside ofthe said drum electrode. vThese electrodes are thus preferably supported on approximately four inch centers and directed substantially ,"perpendicularly to and adjacent portions of the inside surface of the said depositing electrode drum. The said cage-like pointed ionizing electrode structure is in turn supported by suitable clips, as shown at |53-I56 through supporting arms, as shown at |51-I60 which are in turn connected to a rectangular angle iron structure |6| which extends through the length of the ionizing electrode structure and the depositing electrode drum. This rectangular structure |6| is supported near its corners upon four vertically disposed high voltage insulators |62- I 65 which are in turn supported near the end portions of a cylindrical segment-like structure extending through the length of the lower inside portion of the depositing electrode drum and supported at its ends by means of a pair of 1ongitudinal channel ironbeams |61 and |68. These channel arms extend across and are attached at their ends4 to the inside surface of the treater container at'a point opposite and above the belength and width thereof which is supported upon the I beams A|10 and |1| which also extends through the inside lower portion of the depositing electrode drum and are fastened at their ends to l the longitudinal `supporting channel irons 61 and |68. The before described pointed Iionizing electrode cage structure is thus supported from the bases |24 and |25 through the longitudinal channels |61 and |68, the axial I beams |10 and |1| and the high voltage insulators |62|65.

The before mentioned semi-cylindrical segment structure in the inside lower portion of the depositing electrode drum vis divided into three main compartments or tanks T1, T2 and Ts, having bottom sheets |13, |14 and |15, respectively,

and partitions therebetween formed by the before mentioned axial supporting I beams |18 and Y |1|. Two slots or openings |16 and |11 are provided extending along the length of the outer edges of the said compartments T1 and T2, respectively, betweenthe deck and bottom sheets which form inlet ports for liquids removed from the right and left inside surfaces of the depositing electrode drum, as viewed in Fig. 6. The removal of liquids from the inside surface of the depositing electrode drum is accomplished by wipers |80 and |8|, respectively, which extend along the length of the said ports |16 and |11 and are attached to and hinged at the lower edges thereof. The sheet iron baille |82 extends outwardly and upwardly from the edge of the deck |69 along the edge of the said'port |11 to prevent splashings within the treater and liquid dropping from the ionizing electrode structure from flowing into the port |11. Liquid falling from the treatingV surfaces within the treater upon the deck |69 will thus be forced to iiow across the deck and drop through port |16 into the tank Ti.

Outlet pipes |83 and |84 are provided for the tanks Ti and T2, respectively, and a drain pipe |85 is provided in the bottom of the treater conlength thereof upon manifold pipes 20T- 209. These spray manifolding pipes are rotatably supported at their far ends by'means of suitable through the ionizing electrode cage structure by tainer for draining out slops or extraneous aci I'he bottom of compartment Ts is arched in two places to form a semi-cylindrical housing for the wax screw |81 and for the shell of the wax scraper |88. The -said wax screw |81 extends throughout the length of the bottom of the depositing electrode drum and is rotatably supported at the bearings 9| and y|92 and rotated by means of Lasprocket |93 keyed to the wax screw shaft |84. depositing electrode drum through the treater shell, as illustrated in Fig. 8, into the upper portion oi' a wax collecting chamber |95. The said wax collecting chamber |95 is provided with a heating coil |96 and a bottoms outlet |91 and a vapor vent |98.

A plurality of flared triangular shaped nozzles, as shown at 200, are placed adjacent one another along the inside surface of the depositing elec- The said wax screw extends from the trode drum |21 and provided for the application of the wax-bearing oil mixture to be treated upon the inside surface of the rotating drum in the form of a wide layer of uniform thickness. These nozzles 20|)v are supplied with the wax-bearing oil mixtureA bymeans of'a manifold pipe 20|, extending through the'treater head through a flanged inlet 202. said manifoid'pipe 20| andv through the ionizing electrode cage structure at suitable intervals along the length thereof, as

` shown at 205, said open sections being formed by omitting portions of certain of the segments |50. Sufficient clearance is maintained between the nozzles 200 and the inside edges of the said openings through which they exten-:1, to prevent breakdown of the gas space therebetween when in operation it is under a high potential difference. H, I and J are rows or systems of jets pro-- vided for spraying wash liquid upon the inside surface of the depositing electrode drum |21 and they are spaced at suitable intervals along the omitting portions of the segments to allow the sprays of wash liquid from the rows of jets H, I and J to reach and impinge upon the inside surface of said depositing electrode drum |21. The jet systems H, I and J are supplied with wash liquid by means of suitable piping making connection with the manifold pipes carrying the said rows of jets. The direction of the jets may be adjusted by rotating the interconnecting manifold piping from the outside of the treater. W4 and W5 are wipers for the purpose of removing liquid films from the inside surface of the depositing electrode drum each comprising a shaft 2| 2 and 2|3 extending the length of the treater and carrying a felt blade as shown at 2M and 2|5. The felt blade only makes light contact with the moving surface of the drum electrode and the contact pressure between said felt and the drum surface is maintained at the desired value by torsion applied to the shaft, for example, shaft 2|2 by means of a suitable weight 2|6 attached to the end of a crank 2|1 which is in turn attached to theexposed end of the shaft 2| 2 which extends through a suitable stuffing box, as shown at 2|8, on the curved end portion of the treater container head. As described hereinbefore, wipers |80 and |8| are similar to wipers W4 and W5 and serve to gather the wash liquid and the dewaxed oil, respectively, from the inside surface of the rotating drum electrode and to deliver such gathered liquids into the tanks T1 and T2, respectively. These wipers |80 and |8| are attached to shafts |86 and v|88 which rest upon the upper edges of the tank bottoms |13 and |14 at the lower edges of the ports |16 and |11, respectively, and the shafts |86 and |88 extend through the head of the treater, as shown in Fig. 10, through suitable stufling boxes |99-and 204 andcarry cranks 208 and 2|9 to which are attached

suitable weights

225 and 226, respectively. The torsion thus applied to the said shafts |86 and |88 istransmitted to the wipers-|80 and |8| to force them against the inside surface of the depositing electrode drum with suillcient pressure to collect the liquid lm running down the said surface but in the caseof wiper |80 with insufficient force to remove the deposited Wax layer.

Force is similarly applied to the wax Scrapers 88 through the shaft 221, crank 228 by means of l the weight 22s. l Y

through the treater container and which is closed by the flange 2|8 is of suiiicient diameter to allow the withdrawal of the entire wiper W4. The same maybe said of the opening through which the nozzle manifold piping 208 passes and which is closed by flange 2| I, that is, it is large enough to allow the removal 'of the entire assembly of l the jets J from the treater container removing the said ange 2| I.

Electrical connection is made from a suitable source of high voltage unidirectional current to.

inner surface of the depositing electrode drum The operation of the above described optional arrangement of the electrical dewaxing apparatus is as follows: Wax-bearing voil containing solidified wax in suspension,l the wax having been previously .precipitated by some method, such as -chilling to a temperaturebelow the normal cloud v point or pour point of the oil, togetherwith a suitable diluent if desired is introduced into the treater through the -manifold pipeA 20|, the

- branch pipes 203 and is applied in a wide,rela

tively thin layer over substantially the entire width of the inside surface of the rotating drum depositing electrode |21 by means of the series of ared nozzles' 200. During the application of the wax in this manner the drum electrode |21 is rotated at from approximately '1 to 10 revolutions per minute in a counter-clockwise direction, as viewed in Figs. 6 and 1 and as indicated by the arrows 224. The thus applied wax-bearing oil layer ows downwardly under the force of gravity upon the electrode surface toward the liquid collecting wiper |8| and countercurrent to the upward movement of the inside surface of the drum at this point, during which time it is subjected to a high potential ionizingelectric field from the points of the adjacent ionizing electrodes, as shown at |40. The high potential ionizing electric field at this point causes animmeby merely I or J, asvdesired, for the purpose of best remov ing the electrically sweated oil from the exposed surface of the wax layer.

d For example, a preferred method is to subject I the deposited wax layer on the inside surface'of the rotating drum electrode to vigorous washing Y or scrubbing by means of hard sprays. of wash diate electrodeposition of the solidified wax from the downwardly owing oil hn uponl thev upwardly moving'drum surface in the form of a dense, relatively thin layer and this deposited wax is carried with the rotation of the drum to the scraper |88 where it is forcefully removedy and allowed to accumulatebetween the blades of the wax screw |81 which extends along the bot- The evaporated diluent when it is employed inv the process is vented Vfrom wax` collector cham- `ber at |98. The said deposited wax-layer intermediate the points of deposition below the waxy .oil appli-cation nozzles 200 and the said wax scraper |88 is subjected to the high potential.

ionizing electric elds from-the adjacent pointed tom of the drum electrode and is finally carried by said wax screw along the-bottom of the drum through the outlet pipe |83. The deposited wax' ionizing electrodes supported within that portion .of the rotating drum with the result that oilA occluded and entrainedin the deposited wax layer scrubbing operations before being removed by the scraper |88, the washing liquid being introduced through any of the plurality of jets at H,

diluent from jets H and J. Jet J has been found to be of particular importance in serving to dilute the waxy-'oil film which adheres to and is carried over withl the rotation of the drum upon the -f wax depositing wax layer surface and it is important to supply a suicient quantity of wash diluent through the jet J to carry the thus diluted waxy loil downward countercurrent to 1the Vmovement of the drum surface toward the points of application of the wax-bearing oil feed where-l by it commingles with the said applied wax-bearing oil and continues downward to the treated liquid collector |8|. The oil which is carried on over the top of the drur'n past the point of im- .pingenient of the jet J is thus reduced in amount and greatly diluted which is important in reducing the amount of oil removed with the deposited wax and hence is important in increasing cient thickness and density to force it to run back v down the drum .against the rotation thereof or to drop therefrom upon the deck |69 and to be drained therefrom through the ports 16 and into the wasl liquid tank T1.

Thus the deposited wax which is carried'by the rotation of the drum' past the jet J and the wiper W5 is relatively free from adhering oil or, in other words, has a relatively dry surface. Upon continuing with the rotation of the drum between the wiper Wa and the points of impingement of the jet H the thus dried deposited wax layer is subjected to a continued ionizing electric eld from the adjacent pointed ionizing electrodes which causes the occluded oil to electrically "sweat from the wax lay'r Kand to appear on its surface in a thin film or in the formof minute droplets. Th'e application of additional wash oil by means of a hard spray from jets H upon the thus electrically sweated wax layer serves to remove the resultant oil lm from the wax layer and to allow it to flow therefrom down- Y ward to the wiper |80 by means of which it is removed and caused to flow through the port |16 and into wash oil collecting tank T1 from which it may be subsequently or continuously removed layer from which the electrically sweated oil has thus been washed continues down with the rotation of the drum and is finally removed from the inside surface of said drum by means of the wax scraper |88, as hereinbefore described.

The dewaxed oil from which the wax has been deposited, as hereinbefore described, is likewise removed from the drum surface by means of wiper |8| and allowed to flow therefrom through the port |11 and into the dewaxed oil collecting tank T2 from which it may be subsequently or continuously removed through the dewaxed oil outlet pipe |84..

The wiper W4 may be operatedwhen desired in a manner similar to W5 to prevent thecarry over of cil from the point of application of the wax-bearing oil to the deposited wax washing 4and Asweating stage of treatment. The pressure of wipers W4 and Ws and |80 may be adjusted as, hereinbefore described, in connection with the apparatus of Fig. 1, to a value sumcient not only to remove the oil film but also to remove the superficial layer of relatively soft wax which' has been found to adhere to the underlying densely deposited lwax layer. The soft wax layer contains a relatively greater amount 10 of oil as compared to the underlyingmore dense layer of wax. The thus removed soft wax from the wipers W4 and Ws will drop upon the deck |69 and may be washed therefrom by suitable means into the wash oil collecting tank T1. The soft wax layer which is removed by the wiper |80 will be carried with the wash oil removed from the drum surface into the wash oil collecting tank T1. The wash oil containing the small percentage of wax which has been washed' and scraped from the deposited wax layer and which collects in tank T1 may be recycled to the waxbearing oil feed and may thus constitute a portion of the Wax-bearing oil diluent and/or it may be recycled to any one or all of the wash jets H, I and J. Additional washing and scrubbing of the deposited and subsequently -electrically treated wax layer maybe accomplished by jets I and it has been found to be advantageous inV some cases to thus simultaneously electrically treat and wash the deposited wax layer in order to remove a substantial proportion of oil occluded in or adhering to the said wax layer.Y It has` been found to be particularly advantageous to subject the deposited wax layer to scrubbing by sprays from thewash jets which are sufficiently hard to substantially momentarily dislodge the wax from the electrode surface.- The thus dislodged l wax is immediately redeposited under the electric field and the effect is thus substan- 40 tially that of redispersion and redeposition of th'e wax which greatly reduces its oil content and produces a drier wax.

The temperature of the contents of the treater when employing liquid normally gaseous diluents in the wash vjets and/or in the waxy-oil feed is regulated by varying the pressure therein by means of Ya suitable valve on the withdrawal pipe |85 which governs the amount of evaporation of the propane. The treater is thus maintained at a' temperature approximately equal to that cf th'e chilled waxy-oil feed mixture.

In the operations described in .which propane diluents and washes are'employed', the treater 55 operates in an atmosphere of propane vapor confined within the treater container. When other Volatile diluents are employed the atmosphere within the treater shell will consist of vapors of such diluents. The operativeness of the ap- 60 paratus is not` limited, however, to the use of volatile diluents, certain substantially non-volatile diluents,v suchas kerosene and gas oil and medium and heavy hydrocarbon fractions being frequently employed under some conditions. When such materials are employed refrigeration thereof is accomplished by any suitable means of heat exchange. The character of the gaseous atmospher'e maintained within the treater shell although having some bearing thereupon is not of primary importance 'insofar as the electrical ionization effects of the electric treating fields are concerned. It is. of course. necessary to avoid inflammable gaseous mixtures.

The ionizing electrodes I are constructed preferably of pointed wires which maybe 11g to 1A, inch in diameter and from six to twelve inches long. They are supported upon the electrode supporting segments, as shown at 3| in Fig. 3 and |50 in Fig. 1l, by any suitable means, such as by welding as hereinbefore described, extending toward and with their axis substantially perpendicular to the depositing surfaces of the drum electrode.

These pointed electrodes are preferably spaced from one another at distances of approximately two to four inches on centers and their pointed ends spaced from the depositing surface of the drum electrode at a distance just sufcient to prevent continuous spark overtherebetween at the operating potentials. The operating potentials which have been found to be effective for efficient dewaxing of the oil and-efficient deoiling of the deposited .wax are in the neighborhood of 50,000 to 100,000 volts and under these conditions of voltage of electrode spacing a silent electric discharge or corona is observed at the ends of the pointed electrodes and extending toward the adjacent depositing surface of the drum'electrode upon which the wax-bearing oil to be treated is flowed and upon which the wax-bearing oil is washed or scrubbed and electrically sweated'or dried. This electric potential applied' to the pointed ionizing electrodes is preferably unidirectional and preferably of a constantpotential whereby the maximum average potential may be maintained between the electrodes without the spark over. The ionizing electrodes aref also preferably maintained at a negative polarity while treating the majority of waxy oil although in some cases when treating refined oils a positive potential is effective.

Advantages of the process of this invention reside primarily in the improved Aeffectiveness of the wax deoiling stage by employing washing or scrubbing sprays and mechanical wipers and advantages of the process whereby the deposited wax layer upon the depositing electrode surface may be improved in dryness or freedom from oil over that heretofore possible.

The advantages of the apparatus of this in? vention reside in the compactness and eilicient utilization of space per unit of effective treatplishes the same results within the scope of ther appended claims. r

I claim: 1. A process for dewaxing oil comprising precipitating wax in wax-bearing oil, subjecting the mixture to an electric field and electricallydepositing the wax from the oil in a layer upon an electrode surface and wiping said depositing wax' layer while on said electrode surface to remove adhering and occluded oil and to thereby produce a relatively dry waxy layer and removing the -thus treated Wax layer from the electrode surface.

2. A process for dewaxing oil comprising precipitating wax in wax-bearing oil, subjecting the mixture to an electric field and electrically depositing the wax from the oil in a layer upon an electrode surface, washing said deposited wax layer with a spray of wash solvent while under the influence of the electric field and wiping said washed wax layer while on said electrode surface to remove adhering and occluded oil and Wash solvent and to thereby produce a relatively dry wax layer and removing the thus treated wax layer from the electrode surface.

3. A process for dewaxing oil comprising pre-l cipitating wax in wax-bearing oil, subjecting the mixture to an electric field and electrically depositing the wax from the oil in a layer upon an electrode surface, andv alternately washing and wiping said deposited wax layer while on said electrode surface in a plurality of stages to remove adhering and occluded wash solvent and oil and thereby producing a relatively dry wax layer and removing the thus treated wax layer from the electrode surface.

4. A process according to claim 2'with subjection of the deposited Wax layer to an electric field between the washing and wiping stages.

5. A process according to claim 3 with subjection of the deposited Wax layer to a further electric field intermediate the washing and wiping stages.

6. A process for dewaxing oil comprising preface and means to apply oil containing solids to said drum shaped depositing electrode surface whereby the solids are electrically deposited on the drum surface and separated from the oil.

12. Apparatus according to claim 11 with means to subject the horizontal drum shaped decipitating wax in wax-bearing oil, subjecting the mixture to an electric field and electrically depositing the wax from the oil in a layer upon an electrode surface and first removing a superficial layer of the electrically deposited wax and then nally removing the relatively dried underlying deposited wax layer from the electrode surface.'

7. A process according to claim 6 in which the wax removed from the superficial layer of the deposited wax is recycled with wash solvent to the wash jets and re-applied to the depositing electrode from which it is removed.

8. A process according to claim 6 in which the wax removed from the superficial layer of the deposited wax is recycled with lwash solvent to the first mentioned wax-bearing oil.

9. Apparatus for separating solids from oil comprising a depositing electrode surface, means to apply oil containing solids to said -electrode surface, means to subject said oil on said electrode surface to an ionizing electric eld whereby the solids are deposited -in a layer on saiddepositing electrode surface and means to remove only a superficial portion of said deposited layer of solids from said depositing electrode surface.

10. Apparatus for separating solids from oil comprising a depositing electrode surface, means to apply oil containing solids in a lm yon said electrode surface, means tosubject said film of oil to an ionizing electric eld whereby solids are deposited in a layer from said oil upon said depositing electrode surface and wiper means for removing the separated oil from said layer of deposited solids and means to remove said layer of deposited solids from said depositing electrode surface.

11. Apparatus for lseparating solids from oil compiising a horizontal drum shaped depositing electrode surface and a plurality of ionizing electrodes surrounding said depositing electrode surpositing electrode surface to a forceful spray of Wash solvent.

13. Apparatus according to claim l1 with means to subject the horizontal drum shaped de# positing electrode surface to a forceful spray of wash solvent and means to wipe oil from the deposited layer of solids on said depositing electrode surface.

14. Apparatus according to claim lllwith a plurality of wipers adapted to remove liquid from the surface of the depositing electrode.

15. Apparatus for separating solids from oil comprising a drum supported-pn a horizontal axis, a pointed ionizing velectrode adjacent the surface of said horizontal drum, means to apply said oil containing solids to a portion'of said drum surface in the form of a downwardly flowing relatively thin layer whereby it is subjected to an electric field between said drum surface and said ionizing electrode and solids are deposited upon said drum surface, means to subvject deposited solids on said ldrum surface to scrubbing with a wash spray and means to separately remove wash liquid and oil from which solids have been deposited from said drum surface.

16. vIn apparatus for dewaxing oil the combination of a moving depositing electrode surface, a container for said depositing electrode, an elongated blade normally contacting said depositing electrode surface for removing material from said depositing electrode surface and means operative from the exterior of said container for withdrawing said blade intactfrom said container.

17. In apparatus for dewaxing oil an ionizing electrode structure comprising a plurality of spaced circular segments forming an open cagelike supporting structure anda plu'rality of electrode points supported and radially disposed upon said cage-like structure..

18.4 Apparatus according to claim 17 with a drum shaped depositing electrode substantially coaxially disposed with respect to said ionizing electrode cage structure, said drum surface being adjacent and spaced from said electrode points.

19. A process for separating solids from suspension in oil comprising subjecting the oil containing the suspended solids to an electric field and electrically depositing the solids from the oil in a layer upon an electrode surface and wip-A ing said deposited layer while on said electrode surface to remove adhering and occluded oil and to thereby produce a relatively dry deposited solid layer and removing the thus treated solid laye from the electrode surface.

20. A process according to claim 6 in which the superficial layer of the electrically deposited wax