US1578624A - Process for electrical treatment of liquids - Google Patents

Description

March 30 1926.

E. ANDERSON PROCESS FOR ELECTICAL TREATMENT 0F LIQUIDS A TTORNE Y Patented Mar. 30, 1.926.

UNITED 'OSTA ESA ,PATENT OFFICE.

EVALD ANDERSON, OF ALHAMBRA, CALIFORNIA, ASSIGNOR TO INTERNATIONAL PRE- CIPITATION COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALI- FORNIA.

PROCESS FOR ELECTRICAL TREATMENT 0F LIQUIDE. l. y

Application inea November 2o, i923. serial No. 675,819.

citizen of the United States, residing at Alhambra, in the county of Los Angeles, State of California, have invented a new and use ful Process for Electrical Treatment of Liqtion.

This invention relates to a process for subjecting liquids to the action of a silent electrical discharge for the purpose of changing `the physical or chemical constitution of such liquids. 'The invention is especially ada ted for treatment of liquids of poorly con ucting nature and is, particularly designed for the treatment of emulsions of water and oil for the purpose of breaking suchvemulsions or separating the constituents thereof. In this connection the invention is applicable to various emulsilied liquids and particularly to dehydration of emulsions of water and oily-or tarry material, for example, emulsions produced in gas manufacture and consisting of crude oil or products thereof containing petroleum or otherl hydrocarbons emulsiied with water.

De-emulsi'ication or dehydration 'of petroleum emulsions has been effected .successfully in many cases by the application of an electrical eld. Ditliculty 4however has been. encountered in applying this method to dehydration of some emulsions, particularly where the emulsion is of an unusual thick or heavy nature, "or where the emulsion, by reason of its high water content, or vfor other reasons, is of such conducting nature as to interfere with the lproduction of the requisite high electrical potential difference'required for the maintaining of an effective electrical field therein. My invention is particularly adapted to casesof this nature as it provides for the maintenance of an electrical field of sufliciently high potential difference to carry out the deemulsifying operation without undue liability of short circuiting or breaking down the electrical field.

, An important object of the present in 'vention is to provide for subjecting the emulsion to be treated to an electrical field maintained between electrodes in such a manner that a gaseous medium forms a part of the electrical field, thereby preventing or resisting the tendency to break vdown or disruptive discharge or short ciruids, of which the'following is a specicacuit which would exist in case both of the electrodes were in contact with the emul from the discharge electrode, and the ions so produced contributin to 'the effective action of the. electrical fle d in the breaking and separation of the emulsion.

My invention ma also be applied to eleci trical treatment o poorly conducting vliqeol aseous medium in-l eld so as to facilil tate the production of ions by 'discharge nids for other purposes, for example, for

changing the chemical constitution of suchliquids by the4 yaction -of a silent ele/ctical discharge either by polymerization or byreaction with -a gaseous medium in contact therewith to form addition or substitution products. The accompanyin drawings illustrate an apparatus sultable or carrying out the invention, and referring thereto:

lFig. -1V is a tranverse section of such apparatus.

Fig.v 2 is a longitudinal section thereof."

The apparatus shown in -the drawing comprises a tank or container 1 forme preferably as a pan or shallow fiat bottomed receptacle of- `considerable horizontal area, said tank or container being preferably covered or enclosed by a top member indi" cated at 2. Within the tank 1 is mounted' a discharge electrode or electrode system comprising, for example, a series or horizontal wires or rods 3, each of relatively small surface area or of sinall cross sectional area, stretched between horizontalbars 4' which -are mounted oni insulators 5 supported on and extending downwardly from the top '2 of the tank. A wire 6 leads from the discharge electrode system to any suitable means for supplying to rectify the current supplied from a stepup transforme-r 8 which is energized by an a ternating current circuit 9. The tank v1 may be grounded as shown at 20 and the current is completed by a ground connection 21 to the rectifier. l

' Suitable means are provided for supplying to the tank 1 the emulsion to be treated and I prefer to so control .the supply of the emulsion to the tank and the flow thereof through the tank as to maintain a relatively shallow layer of the emulsion on the bottom of the tank below the discharge electrode 3. For this purpose an emulsion supply pipe 10 may be provided which supplies the emulsion yto a launder 11 for distributing the emulsion to the inlet end of the tank y,1.

` From the opposite end of the tank 1 the be supplied to tank 1 by pipe 17, vent valve treated emulsion or liquid flows through a delivery launder 12l which delivers the liquid through an outlet 13 toa settlingtank 14 having an upper outlet 15- for oil ori tar Aand a lower outlet 16 for water'. The bottoml of the tank 1 may be horizontal or slightly inclined towards the outlet end.

To ensure safe operation it is preferable to carry on the electrical de-emulsifying operation in the presence of a gas which is inert with regard to the hydrocarbons which are present in the emulsion, for example, a hydrocarbon gas obtained by distillation from vpetroleum or any other inert gasmay 18 being provided to enable any air within the tank to be expelled.

My v rocess maybe carried out in the labove escribed apparatus as follows:

The oil emulsion or tar emulsion, for exe ample, gas tar containing considerable water emulsiied with the tarry constituent, is sup` plied to the inlet 11 of the tank 1 and flows over the bottom of the tank 1, forming a shallow layer thereon, say from one half to two inches in depth. This layer of emulsion eX- tends below the. discharge electrode members 3 and above the bottom of the tank which serves as an opposing electrode and such potential difference is maintained between the discharge and opposing electrodes as to produce a silent electrical discharge or corona discharge from the discharge electrodes and to maintain an electric-al field of suitable intensity in the space occupied by the emulsion and by the gas above the same. The lines of force of the electrical field thus produced extend transversely with respect to the surface of the liquid and pass partly through the liquid land partly through the gaseous medium above the same. The potential difference required depends upon the spacing of the electrodes and may be, for cxample, about 25,000 volts with a spacing lof two inches between the discharge electrodes and the surface of the emulsion. By reason of the electrical discharge thus produced from s emulsion causing breaking of the emulsion so that there is an increased tendency of the water constituents thereof to settle outfrom the tarry constituents which is lighter. The shallowness of the layer of emulsion facilitates or expedites the settlingl out of the water from the tarry or oily constituent of the emulsion. By controlling the supply of the emulsion in such la manner that the iiow of the same through the tank is sutliciently slow the water constituents thereof may be more or less completely settled out by the timethe emulsion reaches the out-let 13. In general,VV

however, it is more economical to feed the emulsion with suiiicient vrapidity to .cause it to pass through the tank or over the bottom of the tank ina period of time not greater than that required for the breaking action of the electrical field to become fully effective, the settling operation being in the tank llet to which the liquid passes from the de-emulsifying tank 1, and the water and tar .or oil constituents being fwith drawn respectively through outlets 16 and l5 lt will be understood that the emulsion,

` whether of oil and water or of tar and of water, will be heated, if necessary, toI a suitable temperature to enable the various operations of flowing through the .treating tank, of electrical breaking action on the emulsion and of settling of water from the' oil or tar to be effected with the lgreatest performedl economy. lThe separation after the break- Y ing action may be effected by gravity or by centrifugal action. In some cases it may be desirable to add a chemical reagent, for example an agent such as soap, capable of modifying the interfacial tension between the oil and water constituents of the emulsion so as to facilitate or expedite "the breaking and separating operations.

As it is desirable that the body of theemulsiou in the treating tank should be dis- .tributed in arather shallow layer, it will generally be necessary to provi-de a tank of considerable horizontal area in order to provide for rapid treatment of a large volume of emulsion, and the expression relatively shallow layer of the emulsion is therefore intended to mean a layer of small vertical thickness. as compared to the horizontal dimensions of the tank. It will however bc understood that in order to increase the capacity of the apparatus it is only necessary to provide a sufficient number of units, for

example, arranged one above another lor otherwise, the emulsion flowing being dis'- tributed into said units by suitable feed means in such a manner that the emulsionpasses through the several units, preferably in parallel streams.

An important feature ofthe present in vention is that one of the electrodes herein referred to as discharge electrodes is exposed to a gas, thereby enabling rapid productionvof ions which serve to effect the breakingof the emulsion. Another feature of the invention is that the layerA of gas between the said discharge electrode'and the liquid being treated lessens any liability of short -circuiting by reason ofV conductivity ofthe liquid. A further feature of the invention is that the emulsion being treated is distributed in a shallow layery thereby enabling most edective action of the electric eld therein and also expediting the settling orv separation of the constituents in the emulsion which have been broken bythe action of the electrical field.

The invention is applicable to the separai tion of colloidal suspensions in general and ber or receptacle, 1, the space above the in fact to any dispersed system comprising a solid or liquid consti-tuent dispersed in a liquid.in which it isv substantially insoluble or but slightly soluble.

In applying my invention to the-treatment of liquids such for example, as petroleum hydrocarbons for changing the physical and/or chemicaly constitution thereof, n

such petroleum hydrocarbon, for example, distillate, may be introduced into the' champetroleum or petroleum -distillate being occupied by an inert --gas, for example, nitrogen or carbon di-oxide 'or hydrocarbon gas derived from petroleum. Sufficient potential difference is maintained between the electrodes to cause a silent discharge fromthe discharge electrode 3 accompanied byv ionization 1n the gas surrounding andy 1n contact with saiddischarge electrode.. Such ionization in conjunction withthe electrical field maintained between the electrodes causes a change in the physical or chemical constitution of the liquid being treated, for example polymerization thereof. By using instead of an inert gas a gas capable of reacting with the liquid under action of an electrical Held, for example, hydrogen or chlorine, various addition or substitution products may be obtained. By treating a vegetable oil in this manner ineontact with,

hydrogen gas hydroge'nation of the oil may be effected, or by treating petroleum oil in the presence of chlorine gas various substitution compounds containing chlorine may be produced, or by treating Vlinseed oil, for example, in contact. with,air or oxygen, oxidation and/or polymerization thereof may beeffected.

vconstituents of the emulsion.

In generall it-.is preferred to usea unidiy rectional current of high vpotential difference for energizing the electrical field in whichl the above described operations whether of emulsion breaking or otherwise are .taking place and in such case the discharge electrode is preferably the negative electrode. In some cases, however, the discharge electrode may be made the positive electrode and in some cases also it may 'be sufficient to use ahigh tension alternating current for operating the apparatus so that the electrical field maintained between the electrodes is y of an alternating nature. v

By reason' of the electrical field maintained between the electrodes there is produced, in addition to the ionization ejfect in the gas exposed to the discharge electrode, a considerable amount of e eetrical convection orwindage, which .causes agitation ofthe.

liquid and penetration of ions and of portions of the gas into the body of the liquid, y

resulting in bringing into contact with k,thev liquid the ions thatX are produced by the `electrical discharge, and also in bringingv the gas itself intov more effective contact with the liquid. The ions introduced inv this manner vinto the body of the liquid ,y maybe considered the agencies 4whereby electrical and ichemical actions are exerted on the liquid resulting in thede-emulsifieation, polymerization or other physical or chemical changes in the liquid.

Vhile I have described my invention as i. I applied in connection with an apparatus' adapted'to present the liquid to be treated in a relatively shallow horizontalv layer on f the electrode ppposing the discharge electrode, it may be carried out in any appabreaking of such emulsion; the constituents thereof being subsequently separated by settling or otherwise -Or the process may be ,carried out by distributing the liq` uid to be treated on the inside of'a cylindrical chamber by centrifugal action produced by rapid rotation of said chamber, the discharge electrode in that case extending axially within the said chamber and in eontactwith the gaseous medium contained therein. IVith Such an operation applied to an emulsion o f oil and water, the centrifugal action will assist in separation of the It will lbe understood that in this case the opposing electrode will be constituted by the walls of the rotating chamber. The discharge electrode is, in any case, of arelatively limited area and the opposing elect-rode of relatively extended area so that the discharge is mainly from the said discharge electrode by reason of the stronger field adjacent thereto.

lIn respect to the operation of the above described process in breaking emulsions it maybe stated 'that in so far as the suspended particles may carry electrical charges -the effect of the electrical field and particularly of the ions produced thereby may be to react with such charges, for eXampe, by neutralizing same so as to modify the dispersing effect and assist in agglomeration or coalescence of the suspended particles.

While I have described the process as applied to the treatment of a liquid it will be understood that there mav be no especial limitation as to the mobility of the liquid,

for example, the processI may be applied in "some cases to substances of high viscosity,

such as heavy tars, bitumens, resins,` or other substances which are of a semi-solid nature but which are sufficiently fluid to permitof the operation of the process.y

In cases where the process is applied to effect chemical reactions between a gas and a liquid, such reaction may be produced or accelerated by the action of a constituent of the gaseous medium which is produced by the actionof the electrical field or discharge -on said gaseous medium, for example, in the treatment of linseed oil as above described, the'discharge electrode being in contact with atmospheric air and the linseed oil being in contact with the opposing electrode, one ef-A fect of the lelectrical discharge or inoization in t-he air exposed to the discharge electrode is to produce ozone-in the air andv such.

z tainedbetween opposing electrodes, said emulsion 'being in contact with one of said electrodes and being separated from the opposing electrode by a gaseous medium and maintaining suficient potential difference between saidelectrodes to 'produce a silent discharge from the electrode exposed in said gaseous medium.

3. The process which consists in maintaining an electrical field between a discharge electrode of relatively smallareaand an opposing electrode of relatively extended area, the discharge electrode being in con-1 tact with and surrounded by a gaseous medium capable of ionization under the action of an electrical stress and the potential difference'maintained between the electrodes being sufficient to produce such dischargey and introducing a liquid to be treated into said electrical field and in contact with said opposing electrode so that said liquid is subjected to the action of the ionization produced in the said gas, and of the electrical field maintained between the electrodes.

4. The process of'de-emulsifying a liquid which consists inintroducing such liquid into an electrical field maintained between a discharge electrode of relatively limited area and an opposing electrode of relatively extended area, said liquid being in contact with said opposing electrode and said discharge electrode being in contact with and surrounded by a gaseous medium capable of ionization under the action of electrical stress,

and maintaining sufficient potential difference between said electrodes to produce an electrical discharge from the discharge electrode with resulting ionization of the gas in contact therewith in such a manner that the emulsion is broken by electrical action. 5. A process as set forth in claim 4 and comprising in addition, subjecting the emulsion after the breaking operation to a separating operation to separate the cgnstituents thereof.

6. The process which consists in subjecting a liquid while in contact with a gaseous medium to the action of an electrical field produced between a discharging electrode which is in contact with the gaseous medium and an opposing electrode which is in con-l tact with said liquid.

' 7. A process as set forth in claiml6 where? in the said gaseous medium contains a con- .stit'uent which is capable of. chemical reaction with a constituent of said liquid unde the action of the electricaldischarge.

8. A. process as set forth in claim 6 Wherein said gaseous medium contains a constit--` uent produced by the action of the electrical field therein, said constituent being capable of chemical reaction witha constituent ofl said liquidAmder the actionof the electrical discharge. i

9. The process which consists in passing a colloidal suspension through an electrical field maintained between opposing electrodes, said col`.oidal suspension being in contact with one of said electrodes and being separated from the opposing electrode by a gaseous. medium and maintainingV sufficient potential difference between said electrodes to produce a silent dischargeY from nur the electrodes exposed in said gaseous medium. v

, 10. The process which consists in subject ing a liquidwhose surface is in contact with 5 a-gaseous medium to the action of an electrical field whose lines of force extend transversely with respect to the surface ofthe liquid and pass partly through said liquid and partly throu h stud gaseous medium.

In testimony W ereof I have hereunto sub- 10 scribed my name this 25th day of October, 1923.

" EVALD ANDERSON.

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