Патент USA US2404405код для вставки
July 23, 1946. _ c. H. M_, ROBERTS 2,404,405 METHOD" FOR REMO-VIN@ IMPUBITIES FROM MINERAL OILS _Filed Deo. 16, 1959 /00 /zo „,6 // 7 23 I ` /0/ /04 /02 , l/v w-:Nrok CLA UD/us H M. ROBE/ers (l5 ` „HARK/5, K/gcH, Fos Te/P â HAR/Pls A rroR/VE Ys. 2,404,405 Patented July 23, 1946 y MErHoD‘roirREMoviNGIMPUm'rms àmou/r1MINERAL" oil-ls ‘ L:(liand'iïlls t, Calif., `assigne Roberts, Palos Verdes Estates, oÍPetrolite Corporation, Ltd., 1 , 4 :Myi invention relatesytofthe purification Qi, ,oils and, mores-particularly, ,to . ,al methodsând ~, appa ratusoforremoving itvaterrdispersible @ímpllïíties ~ 'A2 ' îordispersioncapable of,> continuons electricite@ ment. By this mocl'e yof,neemt1.011,1it ,ís/possible to Se@ureal desired.,heterogeneity zei-,partitie site 0I' Vfrom ~oi.l, :for examplefsremoving „saline-¿material @mentsfatldifierent sequential positions@ obtain ' tlie process is l also >-applioablefto Marions y Qthßr . oils toßremove impurities! capable` of .aheinigï taken -uplßbyetlemadditìonof water. »the »desired electricallyetreatakrleidispersien. . lian,attemptismadeto addetneientireemount ,of water`r at .a Asingle«_povsitíîori,Lîfollmveçlxbyi @mix Y »It .is ¿not «uncommon Jto „find oils foonft .initie ing ¿step adapted ¿to disper f the Wate »into the y«waterpsolulb1_el ortwaterewettable l impurities ; and, 10 oil, it will be found _ind-_nest that ¿reaffi >most trequentlmethese ,vare-¿present»inftlieoil1in Y, « nitely ¿limitedrmiXing-faotion 4musi? be used; if gthe the form of, or associated-mth, y.Sina-l1 \_;liqu_id droplets )oresolidf iparticles ¿dispersed orsemulsiñed throughoutftheeoil, ‘thong-hún some instances „process is to :be ¿capable ofoontinuouslyâvresolving the emulsion or dispersion intoçtoilzandewater, -- without @the ‘accumulation »of » such:` amount of sludgesasçwould,interfere.iwithsthermaintenançe tlieyr‘maylbe in. solution j.in- ~thef-oil,;;asf in; theqease ofrvoertain-inorganic acids whichare soluble Íboth Íin oil «and «.Water. Such‘irnpurities `are@herein lsiralolejnv,many?,instanoesàto haven-prese «termed «as y.dispersion droplets 4_4 of ,added water “Nvaterfdispersi-ole impurities,” ¿by »wlflich.=term»1.»have reieren’oel to impurities which a quite ¿smallin L_size, » often'. eommensura , „Y may -4 »be ldisperse‘di in :wa-ter,- = either ato , produce .a 20 with l thel dispersed limpuritns `which a; some A-tiniesëpr‘esente-«in iaisize; of about: l, mu. Igfffthe en homogeneous isolution , (as,- inflthe Ycase ¿of Water- - Y» tire ¿amountu of iwater .ist added ;;at:y a .Asingleposi soluble Limpurities »which ‘are- miseible with «or "tionpitßiis rs'ometimesìffound' that ¿an` ,electrically - so'lulolel in, the i Awater and which, ¿when 4¿dissolyed in» «Wa/ter, « mayfsbe regarded asimolecularly -or ion :untreatable emulsion- on dispersion: results if suffi ~ finally/:dispersed therein) „forte produce-a Water 251. ‘oieiitëmßixing action is)appliedftoiinsureîthat some of the: added ¿Water i is .dispersed in; .particles ¿of ~ continuous dispersion-including the impurity ¿as ¿such smalllsize. rlúkewise, While/someV degree'> of theint‘ernalf piiasei (as ».in; the , casefof Water-Wet i lla'eterogeneityïof L=partiole1size of -thezaddediwater table, Iwater'-insolublelimpurities) . can « be obtained. by l an „appropriate-singleemixing The removalof wateresoluble or` `water--iizettable impurities¿ifromtsuoh boils 'ßisia problem which „is 30 step, therange ofëyparti'oleisizes isz's‘onleti-rnes con A„siderably » lbelow` that »Lwfiiiohz` is amostg-` desirable; yin -i'rïequently en countered; and-„Which - is 'grof ¿particu lar importance in'j thef handling: oflp'etroleum'goils, -~tb1e».pro`oess. .'Gnx some Voils-¿tine rangeof particle >size@appears 'quite small ‘iflsucli singlefstepç‘mi-x ingßae'ltionßisîusednasiwilt remove ¿the desiredïpro as dispersedisa‘lt«orgoileíieldA brinçgand „also ¿in the removalßoff reagentsiand reaetiontproduots in re 35 portionmof tlie' impurities. The dispersedpand frequently `very-i'loi’glnly> stabilize`d,‘- condition ofthe impurities crudeAv or topped, A containing salinel Jiriaterial,l such >.makes -it ydifficult ,orf impossible tofaeoomplish- the < desired »purification by :ordinary nonißlecßl‘ìßal methods. lAccording to the p-resentaprocess, 'suoli> impuri ties are `removed-Joy forming/in; anovel manner, an artificial dispersionfìor -emulsionfwhioh _isV oil continuous ,and ,which> includes dispersed Water „droplets of different sizes~ or;l addedfunder `differ ent conditions, this dispersion .being .- treated electrically ¿to coalesce the water which, 'when separated, is found to contain most of the Water L110W#»through a t restricted ¿ori'flc-ze, ¿a l¿more ‘Jorl less »heterogeneous « partiel'e‘JsliZe ¿distributionY »may @be 40 l, obtained; in »Wilicrhl tlie-v particles ~ varyî‘frorn; small --to large LWli-th a- <sing-le‘-predominant-size,ltl'ieiis?ize Y- f requ en_cy distrib-¿tion ollowing~~theß=welléknown probability `curve with asin’g-le -In-ax-iinumatsoine intermediate size depending upon the adjustment of :the «'dispersing ‘means @When the Water is 'added *4i-n- f-two increments, ¿the ` E'first j _to ~`produce particles ~ of esmalleriayerage size; than - `_are Vjlpi'o f_duçed inlthe'ësecond'fmixingstage@ thefelia ‘ " 'tér dispersible impurities, and it is an object of the listieL particle -~size çdistributionfcurve is~seouredjfor present invention to provide a~novel `method op 50V yeafelfrïiiicrement,¿ykflài-le the-"final resultant-ldispèr erating in:A this manner. ' It is another object of the invention to,v intro ¿duce theadded water into the system Vata'plu r'ality of‘points, dispensing the ‘Water lntothe oil in a manner Well< suited 'to pro-duce ‘anjemulsion ' ' Sion »contains particles-»showing two . . aix ‘ima inthe size‘ëfrequerrcy distribution'curve ‘or -resporiding-tò the'adjustment-titte two dispers à 4 than a small amount of water, usually under about 8% and only very infrequently as high as 10-15%. Best purification results are obtained by starting with those of the impurities inthe oil in any def sired ratio to those of the larger sizes, thereby permitting great flexibility in adjustment of the treatability of the final dispersion, together with ability to obtain an increased degree of removal of the highly dispersed impurities; whereas, when using a single dispersing step, it may be'possible to secure enoughparticles of the desired small with an oil containing Ano more than a few per cent of water, for example, an oil containing from ¿a fraction of 1% up to :5f8% ,and Ihavea decided preference »for oils inthe-lower' portion of this range if a high percentage of the impurities is to size only at the expense of'obtaining too lowv` a ' » be removed. l Thewater which I disperse sequentially into concentration of particles of the desired larger sizes, thereby leading to .difficultiesV in theV sub- K' the oil’preparatory to electric treatment should sequent electrical resolution due to formation of be relatively fresh, by which term I have refer sludge. , Y, , ence to water capable of taking up, or becoming . It is an Vobject of the present invention to pro-V duce an electrically-treatable dispersion vrof de sired heterogeneity as to the size of `dispersed water droplets therein. It is another object ofthe present invention to ‘ ` add water to the system at two or more points vvassociated with, the Water-dispersible impurities to ‘be removed. This relatively fresh water need not be distilled Water and need not be entirely devoid of the impurities to be removed or other chemicals or minerals, and, in fact, the process is improved on certain oils by the presence of separated by one or »more mixing zones in which 20 `small amounts of chemicals, as disclosed in cer a controlled mixing action is applied. ~ ‘ ` ~ Another object of the present invention is to disperse a portion of the added Water into the oil in theform »of relatively small droplets, and to disperse another portion of the added water into the oil at a later time, the later-added water tain copending applications, for example Nees, et al., Serial No. 312,745,5now Patent No. 2,380,458: It is imperative, however, that if the incoming yoil contains dispersed impurity-containing drop 25 lets, the added relatively-fresh Water should con tain- these impurities, Vif at all, in concentrationsY ` being present in the form of droplets which are _ materially lower thanthe originally-present drop lets, and if the oil' contains no such original droplets, the `relatively fresh water should have a» « -Further objects vand advantages of the inven-, 30 concentration, if any, in the impurities to be re moved Which is very lovv.«A . ' tion will be made evident hereinafterto those Y Ineiïeclgrthe process adds droplets of relative skilled-in the art. ~ ‘ Vly fresh water tothe Voil in controlled dispersing A The process is particularly adapted to the puri fication of oils prior to subsequent refining steps; ` steps so that .the electric ñeld can coalesce the for example subjection to distillation or crack 35 dispersed Water and exertïa powerful action mov of anl average size larger than those produced inthe first dispersingfprocess. - ing temperatures. »It is capable of taking out, -and particularly applicable to the removal of, -impurities which, upon heating. to refining or cracking temperatures, comprise lor form acids? ing theiinpurities into the relatively fresh wa ter. Following separation of the coalesced wa ter, the oilwill usually >still contain certain dis persed water droplets present in amount not more or other materials-having a tendency to corrode 40 than a few percent, andpreierably less than f or form deposits in the subsequent refining equip v nient, or having a tendency to deleteriously af fect the quality of the final products. Purifica tion by the present process makes possible longîzì `trouble-free runs on such subsequent equipment, and they process can well be operated to be main 2%, but such dispersed water will correspond predominantly tothe added relatively fresh wa ter, and theY water content is made low enough so as not to be objectionabler in subsequent _re ñning steps, if used. The necessity forvuseof a ' -relatively fresh> water. will be readily apparent tainedon-stream with this subsequent reñning from an example assuming the presence of 1% equipment with no appreciable loss of oil.Y On of brine> in the incoming oil andthe presence the other hand, the process is not limited to the f, >of A1% of water in the oil resulting after sep treatmentof oils preparatory to further refining. 50 aration of the coalesced water. If this >incom The oil with which the presentinvention is Y ing oil contained 100 pounds ofÍsalts per _1000 concerned _can be any oil having suñîcient re barrels of oil, these saltsbeing, for instance, pre sistivity to sustain an electric field at coalescing Y dominantly magnesium and calcium chloride, and potential when this oil is present in Whole or in , " if the added water is of the saine concentration part as the continuous phase of an emulsion or in these impurities as are the original water dispersion in which the added Water is dispersed in accordance with theinvention. Petroleum oils salts in amount about 100 pounds per 1000 bar Y are particularly well adapted for treatment by the process, whether in a crude state or Whether vresulting from previous refining steps. In the >latter connection, the process can be used on topped`oils or on various fractions obtained from oils. - Such oils can be dry, or substantially dry, or. droplets, then the separated oil will contain these rels, and the total reduction in the> impurities willVV be negligible. -On the other hand, when operat ing with a relatively fresh water under the same circumstances, reductions in salt content of more than 90% can be readily'obtained. The electric field /utilized'in the process should be capable of bringing into combination or asso can contain dispersed water with which atleast 65 ciation the impurities and the droplets of rela some of the impurities may be associated,_this tively fresh water, and should, likewise, be capa . Water being dispersed Vin the oil to form what is hereinafter. termed “original Water droplets.” .e The?process is not well »adapted to oilsl of -high _ ble ‘of coalescing the water into masses of sulfi ' cient size to be readily separable from the oil.` The eoalescing iields herein-used are usually of water' content, for example,` oils containing from 70 the high-Voltage alternating current type, though ¿20%, to‘50% of Water (percentages here and else coalescing iieldsformed'by the use of directeur where are by volume), and such oils are prefer rent can, in some instancesybe substituted, though ably first dehydrated to produce the starting ma terial for the4 present purification process. The l the> 'process is 'not concernedwith low-voltage preferred oils are -those which contain no more rá fields exerting only a cataphoretic action', `Í “ ' " 2,404,405 adjustable weightY 4 l! so» that. the'l mixing. action The process can best bedescribed with refer ence to they treatment of mineral oils containing may be adjusted by moving the. weight. 41.. water-dispersibleV impurities, and the» process hereinafter described will be exemplifiedA in this manner, without intention of limitation. ' ' Thedispersion thusA formed.Í is shown asamoving along the pipe. 231 to. ajunctio'n. 44 under the ac. tion ofI the pumps-21' andl 261, Hera, the second portion of relatively fresh water isv injected through» a pipe 45' after'being- suitably heated, if desired,'in» a heatexchanger 4t.. This relatively fresh water is moved into the pipe 45= through a ' Likewise, appropriate apparatus willbe shown as- exemplary, and inthe accompanying drawing: Figure 1 illustrates diagrammatically one em bodiment of the appara-tus capable» of carrying 10 valve 45a therein by a pump 4l intaking from a out the process;V second- tank 48. some instances, a simple in Figure 2 is an enlarged view in vertical section jection of the second portion> of water int-oi the of one type of mixing means useful in the process; oil streamv will mix the! two and give a .desired Figure 3 is an enlarged sectional View ofr a por type of dispersion- containing, for examplavsmall1` tion of the electrode structure shown in Figure 1; and ` - 15 droplets of relatively fresh water as dispersed into the oil by the'rirst mixing or dispersing step, and larger droplets of‘rel'atively fresh water dispersed into the stream“ by the injecting- action- adjacent Figure 4 is an enlarged sectional view of the distributing means shown'in the‘ele'ctric treater of Figure 1. n y Referring particularly to-Figure l1, theÁ oil' to be the junction 4'4". v However., in many» instances, it treated may'be moved through pipe> >I El by a pump 20 is desirable to mix the constituents further and a mixing means 5Fl can be used in- this connection. I I. If this oil is already of low water content, it This mixing means is shown as comprising a can be discharged through pipe l2 and 'valve I3weight-loaded valve V5i ` similar to that previously into a tankv I4. If the water content ofthe oil is described. The resulting dispersion is delivered high, it is preferable first to dehydrate the oil'V by electricaL‘chemical, centrifugal, or other means, 25 to the electric treater but, if desired, can be addi tionally heated or cooled by use» of a heat ex or merely by settling. This can be accomplished by opening a valve l5 so4 that theincoming `oil moves to a dehydrator l5 from which the excess changer 53, 2|, which usually supplies suflicient pressure to into the pipe 23 in proportioned amount, this ' A valuable adjunct to the process and appara water can be withdrawn through a pipe’ I‘1, >and tus thus far described, and which can be used in the oil of low water contentv through the pipeV |'8 30 place of or to supplement the dispersion of the i'lrst portion of the relatively fresh water inthe for delivery to the tank I4. ‘ " The oil to be purified is withdrawn from the oil, is the addition of vsteam to assist in the forma tank i4 through a pipe 20 by the action of a pump tion of the desired dispersion. If steamv is moved move the oil through the system while 'main 35 steam will be dispersed throughout the oil stream taining superatmospheric pressurev on the oi'l and> will almost instantaneously condense: ‘De pending upon the manner of injection of the until' it discharges from the electric’ treater. If desired, the oil flowing in the pipe 20 may be steam, particles ofv relatively fresh water of> dif heated by passagethrough a heat exchanger 22 ferent size can be thus dispersed, the relatively and then flow along a pipe 23. 40 ' Any suitable means can be used for dispersing relatively fresh water into this oil in two or more fresh Water in this instance comprising the con- À , densate. Usually, such dispersed droplets formed by the injection of steam are quite small in size, positions, the dispersing steps being such as to facilitate the operation of the process, asv herein before described. In the exemplary showing of Figure 1, the relatively fresh Water is added in two stages, and dispersion is effected by flow through mixing valves. For example, the first portion of the relatively fresh water may be sup plied through a pipe 24 to a tank 2'5 and, from 50 this tank, proportioned into the oil stream- by use of a pump 25, moving the water through pipe 2l and valve 27a into the oil stream vin the pipe 23 at right angles at the junction 28.` If desired, this portion of the relatively fresh water can be’ heated in a heat-exchange means 29. Injection of this portion of the added water into the oil stream mixes the water with the oil and forms a preliminary dispersion atr the junc tion 28. However, in most instances, it is de sirable further to mix these constituents and this can be done by use of Aa suitable mixing meansSil disposed in the pipe 23 beyond the junction 28. and this is often desirable in the process. As shown in Figure 1, steam from any suitable source may be moved through a pipe 5,1 and, upon opening of a valve 58, will be delivered to the pipe 23 through V.a pipe 59. Alternatively,'or at the same time, upon opening a Valve 60„ the Steam may be delivered in lproportioned amount to the pipe 23 through a pipe 6I. Correspond ingly, steam» may be delivered either prior to or after dispersing the ñrst portion of relatively fresh water into the oil through the pipe 2ï. Often, such injection of steam can be used to elim inate the addition , of relatively fresh lwater through the pipe 21, relying upon the later addi tion through the pipe 45 to supply the somewhat larger droplets of relatively fresh water which are desirably present in the dispersion undergoing yeo electric treatment. Y l While various electric treaters can be used in the process, Figures 1 and 3 show an embodiment which has been found to be very satisfactory and This mixing means is preferably of the once which is claimed in the application of Harold C. through type and may well induce the desired 65 Eddy, Serial No. 218,681, now Patent No. 2,277,513. mixing action by the turbulence attendant upon This treater is preferably, though not necessarily, change in direction of flow or passage through a of the type in which electric treatment yand sep restricted oriñce. One readily-controllable type ' aration take place in the same tank. Such a tank of mixing means is shown in Figures 1 and 2 as is indicated by the numeral 10, and after opera comprising a weight-loaded valve 3l providing a 70 tion for ,al period of time, containsr bodies of oil seat 32 in a partition 3‘3. A valve member 3d is and water TI and 12, shown as separating at the vertically movable toward and away from the surface or interface '13. v yseat 32 by use of an arm 36 pivoted at 31 to a post 38, and pivoted at 39 to a plunger 40 connected . to the valve member, The' arm 36 carries an "75 In view of the electrical system utilized, it is i desirable to maintain this surface or interfacer 1.3. at or about the position shown, and to accomplish 2,404,405 8 This type of electrode structure presents a ‘min imum impedance to gravitational separation .in this, therateof withdrawalof treated constitu ents from the tank 10 may be. varied. The system shownincludes a water draw-oiî pipe 14 equipped the _tank 10, the rings and supporting means therefor covering only a small fraction of the total cross-sectional area of the tank 10. Furthermore, the interstitial character of these electrodes'per mits free ycommunication between the electric terminating at its upper end with the' body of Voil fields and facilitates rapid removal of coales’ced " 1| and being provided at a4 position near the in water masses therefrom. terfacial zone with a chamber 18. ` , The incoming dispersion or emulsion is pref «An oil-water interface will thus form in~ this 10 erably delivered from the heat exchanger 53 chamber and any suitable means can'beused ,to through a, pipe `| I5 directly into the lower treat control the withdrawal from the tank 10 to main. ingspace 98. It is preferred .to move the dis tainV the interface 13 substantially constant in po sition. A float19 is shown in this connection and ' Y persionrradiauy outward in this neld so thatV it is mounted on apivoted arm 8_0, which is con 15 moves successively through vthe edge-to-edge ñelds and sets up desirable circulations intofthe nected by link 8|, with a link 82 forming a part treating space 98 from the zone thereabove and of the operating system for the valve 15. „The from the zone therebeneath, thereby Vpermitting float 19 is of such character as to sink inoil and recycling of some of the treated constituents float in water. Correspondingly, when the inter face rises, the float moves upward and, through 20 through the electric field. Such radial discharge may be `effected through use of a distributor IIB, links 8| and 82, the valve 15 is opened ~suiiiciently best shown in Figure 4 as including Va housing | |1 to increase the flow therethrough, thus tending attached to the pipe ||5 and provided withl a to lower the interface 13 until the float returns ’ with apvalve 15.4 Extending upward from the pipe 14, and thuscommunicating with the water in the lower part of the tank 10, is a pipe 16, this pipe cap ||8 which may be permanently or adjustably of treated oil moving from the upper portion of 25 spaced therefrom to provide an annular passage ||9 through which the dispersion is delivered to ` the tank 10 through a pipe 85 maylsi'milarly be the lower treating space 98. A spring-loaded dis varied by adjustment of a valve 86 therein'. y the valve 15 to its previousposition. The amount tributor can be used in this connection (of the This lpurified oil maybe moved to'subsequent typé shown in Figure 4) Vand can be made to refining equipment, either with orl without addi tional settling time, but is shown as discharging 30 exert a mixing action on the incoming constitu ents at the point of discharge into the ñeld, this into a tank 81 from which any water separating being‘often desirable though not essential to the from the oil can be withdrawnÍ through a pipe 88, operation of the process. For example, the cap the oil being pumped from this tank to suitable ||8 may carry a rod |20 slidable ina spider | 2| refilling equipment for distillation, cracking, or and carrying a passaged spacer element |122. By other processing, if desired. The valves 15 and disposing a compression spring |23 between the ' 86 act to maintain a; >all times sufficient super spider |2| and the spacer element> |22, the cap atmospheric pressure in the tank v'|0'to prevent ||8,'will be moved?resiliently downward and will such vaporization of the lighter fractions of the be displaced upward a distance determined by oil as might interfere with satisfactory separa the rate of input of the dispersion. Various means may be utilized for energizing The electrode system of this treater is disposed the electrodes to establish suitable electric ñelds in an oil environment of sufficient resistivity as in the treating spaces 91 and 98. In the construc to permit maintenance of the electric ñeld under given operating conditions. In this connection, _tion shown, all of the electrodes 90, 9|, 94, and 95 are maintained above ground potential, the I prefer to use a live electrode structure suspended only grounded portions adjacent the electrodes Y from insulators 89, and shown as including' an being the distributor HB, Ythe tank 10, and the upper live electrode 90 and a lower live electrode body of water 12. By proper design of the elec 9| suspended therefrom and electrically con trical system, the potential between the inter nectedtheretov by rods 92. - Suspended from an mediate electrode structure and the electrodes 90 insulator 93 and positioned between the upper and'9l can be made much higher than the p0 and lower live electrodes 90 and»9| is an inter tential between any of the live electrodes and mediate live electrode structure, shown as in the grounded portions of the system. In Figure cluding electrodes 94 and 95 joined by a1 con l, such a lsystem is shown as including lîWO trans ducting rod 96. These electrodes cooperate re spectively‘with the electrodes 9|]V and 9| in pro 55 formers |25 and |26 Yproviding secondary wind viding upper and lower‘treating spaces 91` and Y ings connected in additive relation. One ter minal of each secondary winding is grounded as 918. indicated by the numeral |21, and the remaining Theelectrodes 90, 9|, 94, and 95 are preferably terminals are respectively connected to the inter- ~ of interstitial character, and the constructional details of the embodiment shown'will be clear by 60 mediate electrode structure and to the upper and reference to Figures 1 and' 3. Referring to Figure lower live electrodes 90 and 9|. Suitable switches and control means for limiting the current may beV used'in the primary circuits of these trans 3, the electrode 90 may include'a plurality of con centric rings lllß mounted on pins |0| secured to cross arms |02. Each ring provides ajlower‘annu Assuming, for example, that each transformer lar edge |04 adjacent which thel electric field is 65 'very concentrated. The ‘electrode ‘94 is similarly develops a potential of 121,000 Volts, the potential formers.> formed, with a pluralityv of concentric'rings |05 terminating in upward-extending annular edges |09. By disaligningthe rings |00 and' |05, the K v ' A across the upper treating space 91 will be V24,000 volts, as will also the potential across the lower treating space 98. However, the potential be tween the distributor ||6 and the electrodes 9| or 95 will be only 12,000 volts, as will be the ñeld inducing potential between the‘lower electrode 9| and the body of water 12, and which ñeld is often desirable in further treating the settling water preferably of smaller diameter than the electrodes 75 Vmassesas Well as in sludge elimination. Use of 90fand 94. most intense portion of any electric'ñeld estab 70 lished in the treating space 91 Will-be inclined~ as indicated by the dotted lines |01. The elec trodes 9| and 95 are similarly- formedY and are 2,404,405 >such a system tends .to »prevent short-circuiting to tliedistributor and .also Ypermits introduction of the dispersion directly .into afield ofhigh volt age. It will be „apparent lthat by using different _quence can Abe used WithoutA departing from the .electrode` spacings and/or- different potentials, viously described, .or these actions can be used spirit _of .the invention. The smaller ,droplets `can be >'formed either exclusively by the mixing means 30 ror by the injection of steam, as pre the voltage gradients in the. spaces 91 and 98 and together. If steam is introduced through the the intensities of the treatingactions therein may pipe .59 .to supply the small droplets, the rela tively `fresh water added through thepipe 2,1 can be controlled as desired -to .produce the best treat ing effects on the oil being processed. b_e dispersed into the -oil to form droplets of an The preferred mode of operation is one in 10 average size somewhat larger, .and ‘the relatively which the dispersing stepsare socontrolled as to fresh Water added through the pipe, 4'5 lcan be produce a dispersion which .is continuously >re dispersed in vsuchrnfianner thatzthe average size of the resulting dropletsv is even larger, thus mak ' solvable With the aid of an `electric field into oil and water, Without the accumulation of such ingpossible a _Wide range-of particle size. amount of sludge -as Would yinterfere with the 15 I usually 4.und it desirable to ,add atleast the last portion ofthe relatively freshwater to the maintenancefof the electric field. This resolution can `be effected by coalescing treatment .in the oil at a position quite close to the electric field, electric field, aided, if desired, by .recycling , and, in most instances, itis desirable kto add the first portion immediately ahead of the Isecond through the electric field Vas mentioned above, followed by settling or other separating steps. 20 portion. However, if desired, the -ñrst portion If the dispersing steps are properly controlled, can be added to the oil a considerable time -prior resolution into oil and water can be obtained, to the addition ofthe laterjportion Without de the Water being substantially free of oil, Within commercial tolerances, .but now containing the parting _from the ‘spirit of the invention. impurities extracted from the oil, either in their 25 original or `somewhat modified state. Such a ` One-Verydesirable _mode of operation in purify ing an oil containing dispersed impurities is'to avoid predominant combination of these dispersed impurities with ‘the relatively -fresh :Water until mode of operation Will prevent'the accumulation of suchamountof sludge, comprising unresolved the dispersion enters the electric ñeld. This in sures that droplets of the relatively fresh Wa emulsion, as would ,interfere with the mainte nanceof the electric field. 30 ter "will be present in the dispersion ìto be acted If the incoming .oil contains .suspendedim upon by the field to bring them intoassociation or combination with the dispersed impurities. purities, these yare Aoften yof very small size.. It 'The amount of relatively fresh Water used in has been found desirable to have some of the relatively fresh Water .droplets of a commen thevprocess Willvary with different voils and With -surate oronly slightly larger size as this appears 35 the >desired degree of purification. 'I'he Water content of the dispersion entering the'electric to `increase the total >percentage reduction of impurities. If the relatively fresh water is added field should not be so ‘high as 'to producefinvefrse phase emulsions of the oil-in-Water-type in such at a single point, vfollowed by -such mixing as will `produce particles-of this small, size, itis found amount as cannot be handled by the electric ñeld. onmany voils that sludge ,difficulties are encoun 40 The vupper limit onmost oils appears to'be be tered, as evidenced either by the inability to' low 40% or 50%. Usually, the Water content of the dispersion 'is Aconsiderably Aless `and vmay maintain coalescing potentials across the elec commonly >rangebetween 8% and 30%. Ifjthe trodes .during continuous operation, _or Iby the progressive accumulation of >alayer of vsludge in incoming voil contains vrno Water, or contains'no the interfacial zone which -~eventually may build 45 more than 2% or 3% vof water, the total amount of relatively fresh water added Will usually be up either to short-circuit the eelctrodes or to found within the range of 5% vto >20% 4to 'bring gradually pervade the >bodies of -oil and Water, the total Water content of ‘the dispersion to at thus preventing the continuous >Withdrawal from least about 8%, and the most desirable percent the treater of substantially oil-free Water and 50 age can be determined empirically. Likewise,-the oil of suitably low Water content. By the present invention, I can add a portion relative amounts of Water »added at the different of the yrelatively fresh Water at one stage of the stages of the process will vary with' different »oils process and control the dispersing action toppro andgno fixed Avalues can begiven. In some in- ’ duce such ,small droplets of relatively ~fresh wa stances, the proportions added through the pipes ter, and can add another portion of the .rela 55 21 and 45 can be commensurate With each other tively fresh Water at another stage of .the proc but, in other instances, itwill be found desir ess and control the dispersing action to produce able to introduce relatively less Water through the pipe 21 than through the pipe 45. droplets of relatively fresh Water of an average size larger than those produced in _theñrst stage. If mixing valves aroused to Vdisperse the rela In this manner, I can control very definitely the 60 tively fresh Water into the oil, thepressure drops proportion of small droplets and the proportion thereacross willvbe controlled to yproduce the de of larger droplets, and, if desired, can produce a sired type of dispersion, as outlined above.l No dispersion containing Water droplets differing in fixed values Vcan .be given in this -connection'fon size very materially and of a` homogeneity range Withsome oils, the -total drop in pressure from 4the considerably different and larger .than is pos p_ipe‘20 to the interior of the treater can be much sible in other processes. This has beenfound larger than with .other oils. It Vcan be said, vhovv very >desirable and conducive to `ahigher per ever, that the >particle size of the relatively fresh centage ,removal of impurities, _as well as >mak Water decreases as the pressure drop vacross an emulsifying valve increases. >Correspondingly, if ing possible the continuous treatment of .Oils kat -high throughput .rates with substantially _com 70 the relatively fresh Water introduced through the plete vresolution While still obtaining the desired pipe 2.1 is to form the _desirable smalldroplets, reduction „in impurities. , . the pressure drop lacross the mixing 'valve 3| .I prefer to `disperse „the _smaller droplets in will usually be greater than the pressure, drop the oil prior to the dispersion of the ,larger drop across the subsequent valve ~5l. It will be un lets ~.in the `system sl'iovvn,y but the 4opposite se derstood that the. desired mixing Yaction can be 2:1104, ¿10,5 . mentioned above so as to be effective in removing valvef15l', orequivalent restriction, may some timesbe eliminated .andreliance vplaced- upon turbulence. in the >pipe H5 `or in the distributor '.Ill-iY Lto yform the desired. dispersion. Once the small.. droplets of relatively fresh water are dis persed in ,thev oil, they will-not beV materially disturbed by.a Vlater and relativelyflessV intense - ' - » impurities from the oil. Q ' a combination of the water from the tanks25 or 48 and the eiiiuent water from the treater.y B'y blendingthe eiiluent water with the water` nwith-> drawn from only one of these tanksyit is thus possible to secure a multi-compositionl system, tivelyfresh waterrat superatmospheric pressure, and it is often desirable in this instance to have particularlyïin the system> shown in lFigure l. The pumps 2|', 26, and“, as wellas Ythe >valves 58er the smallest droplets formed by the condensing of steam, with droplets of next-larger average k:tIL'can be yused- to proportionthe( oil andvwater size comprising some >of the eilluent water while the droplets of largest average size contain less Vconstituents». ~ The pressureY »exerted by these pumps islpreîferablyV suflicientrto force _the d_is-4 . persion into >the' treater and maintain a super y20 atmospheric/«pressure therein. Pressures Ain the treater tank 'HlV between Y10 and 50 lbs/sq. orgabOVe, can be used but, in'most instances, a or none of the ellluent water. Y averagesize composed in part of eñluent water and the droplets of larger average size composed of .the water in one of the tanks 25 or 48, usually the latter, though the invention is not in all in -25 stances limited to this mode .of operation. This velectric iield is-preferably superatmospheriabut the most desirable temperature will vary with different» oils.A ~Ordinarily,- temperatures .from 1009-1“,V up to fthe 4boiling point of -wate'rr> at the , Even aside from the use of Asteam in the process, itis often desirable to have the droplets of smaller pressure'in'this-tank of about 25flbs./sq. in. is. y appears to lead to improved treatability and ex cellent operation of the process in general. Various changes and modifications can be made without departing from the Spirit ofY the inven tion as defined in the appended claims. ab pressure existingrinthe tankV ‘l0 can be used with »success-¿and some oils- are susceptiblerto treat-V Y ment at atmospherictemperatures. y , persed droplets, the additional and supplemen tary relatively fresh water may often desirably be y , , y When using steam toform the smallest dis- . Itis preferredto- mix> the oil with Vtherela V . can .be determined empirically. The resulting combined waterk should still be relatively fresh as thegmixingor dispersing means. Likewise, >the ' Y 12Y tivelyr fresh and eiiluent water, andthe best ratios _stricted passages Í can be .substituted . as y forming ¿ Ydispersing >or mixing> action. _ 45a and |45 will control the proportions of rela obtained .without _i~e.~io1d;ing_.Y to . adjustable V.Lor .weight-loaded valves, and suitable orifices,Y orjre I claim as my invention: , TheY heat 1. A process for removing water-dispersible im-„. t' « can -befsupplied entirely by use of theheat ex-. Y changer 53,-or'the Voil-and water constituents can 35 purities from a mineral.y oilfof low or negligible Water content, which process includes .the steps be preheated Vbythe use >of the heat exchangers of: adding relatively fresh water to said oil and mixing the added water and the oil in aiirst 4VThepreiîerredV mode of operation isV to` use Va mixing step to form an oil-continuous dispersion process which is continuous throughout,»for ìex ample, one-in which Vthe portionsY of` relatively 40 containing the relatively fresh water in the form of droplets; later adding more relatively fresh, -fresh water are> added successively to al stream of Water to said dispersion and mixing the later Voil.^-- However, semi-continuous - or batch vopera added Water and said dispersion „in a second mix tions are within the contemplation of the pres ing step to disperse the later-added relatively fresh water into the oil-continuous dispersion in " Injsome Vinstances-it Vis desirable to the process 'the form of droplets 'in the oil, said mixing steps - to re-use a portion of the water separating in the 22,29, or 46.-. ent invention. _ »- .. ^ . . ` » . .' . being controlled in such manner that the drop electric‘rtreater, -re-combining this portion with l lets of the relatively freshwater later added are Y a more -pure'water before dispersingit into `the of an average size diiïerent from the droplets of oil.¿*Theîrelatively'fresh water resulting from - the relatively fresh water ñrst added toV produce an emulsion containing'diiîerent-sized droplets of the water suspendedv in the oil; subjecting said suchY a combining step gives improved results` on 7 Y many-¿oilsr as evidenced by decreased sludging tendencies, lower cuts of the purified oil, and emulsion to the action of an. electric lield of higher process efficiencyV invv general including a greater percentage removal of impurities.` While _ thereasons for these phenomena arenot com-` » su?licientv intensity to coalesce the water to form coalesced masses comprising impurities from the oil; and separating the coalesced masses from pletely understood,Y it has been discovered thatV the oil. the eiiluent watercontains, asa result of the proc- s assisting inthe resolution ofV water-in-oil emul . ` v . Í 2. A process for removing saline material from e'ss, desirable counter-emulsifying agents` extract >ed >from the-oil, Ythese agents being of the type a mineral oil of low or negligible water content, said saline material being dispersed in the oil in the form of small saline particles, which proc ess includes theV steps of : ñrst emulsifying into said Voil small droplets of relativelyfresh water of a size commensurate with the dispersed ‘saline particles; then emulsifying into the oil larger 60 If/such a mode of operation is desired, a portion Vof the'elliuent water can be moved through pipe |40. as *,controlled by valve vHH and delivered through-another valve I 42 to the pipe-2l. The M0 4canÃcommunica-te with the intake ofÍth'e . _ dropletsv of relatively fresh water to produce _an oil-continuous emulsion containing `dispersed , pump„.26 .orrmayïbe equipped’with a separate saline particles along with said small and said .-.pumptfor delivery of the effluent water» tothe ' larger» droplets; subjecting the oil-continuous i, discharge side of thepump 26. Y . „ emulsion to the action of .an electric ñeld to îj’_L«Similarly}if}it-is-desired to'blend a lportion of coalesce thewater andbring the saline material Y »theefIiuent-waterlwith the water drawn >from‘the into assoôiation therewith; and separating the ,.tankßß, YAalvalve |45. in a pipe |46Ícan »be opened _ `to deliverall- or aportionof the stream v'fromthe .pipellllûlt'othepipe 45. y coalesced 4Water and its' associated saline mate . The relative settings of valves YZ'Ida'ndp l|42 or `rial fromtheoil. 75 ._ l ,_ » ~ 3, A Continuous process for'removing water 2,404,405 13 14 dispersible impurities from a mineral oil of low or negligible water content, which process in cludes the steps of : continuously mixing with water content, which process includes the steps of: first adding to the oil and mixing therewith in a first mixing step a -iirst portion of relatively fresh water to disperse the relatively fresh water into the oil as droplets of heterogeneous particle a stream of said oil a proportioned amount of relatively fresh water to disperse same through out the oil stream in the form of small droplets size with an intermediate particle size predom to form a stream of oil-continuous dispersion; inating in number; then adding to this disper later continuously adding to the stream of oil~ larger than said small droplets iirst dispersed in sion and mixing therewith in a second mixing step a second portion of relatively fresh Water to disperse the water' thus added into the oil as droplets of heterogeneous particle size with an intermediate particle size predominating in num ber, the intermediate particle size produced by said ñrst mixing step being smaller than the in to the oil to form a stream of a resulting electri 15 termediate particle size produced by said second continuous dispersion- another proportioned amount of relatively fresh water and mixing this water with the oil-continuous dispersion to dis perse this water into the oil of the dispersion in the form of droplets having an average size cally-treatable oil-continuous dispersion capable mixing step and the range of particle size be of being continuously resolved with the aid of a coalescing electric field into oil and water with out the accumulation of such amount of sludge tween the smallest droplets produced by the ñrst mixing step and the largest droplets produced by the second mixing step being greater than the range of particle size produced by either of said mixing steps individually; subjecting the result as would interfere with the maintenance of said electric field; and continuously subjecting said stream of said resulting dispersion to the action of such a coalescing electric ñeld to coalesce the water into masses of sufiicient size to settle from the oil and collect as a body of water below said electric field. 4. A process for removing water-dispersible impurities from a mineral oil of low or negligible ing oil-continuous' dispersion to the action of a coalescing electric field to coalesce the dispersed droplets thereof into masses comprising said im purities and of a size to settle from the oil; and gravitationally separating said masses from the oil. ' CLAUDIUS H. M. ROBERTS.