US1276387A - Method of separating associated liquids. - Google Patents

Description

C. W. McKlBBEN.

METHOD OF SEPARATlNG ASSOCIATED LIQUIDS.

APPLICATION FILED 1AN.22. 1918.

Patented Aug. 20, 1918.

mac w v CHARLES w. Morn 333mb]? nous'rorf, TEXASQ METHOD OF SEPARATING ASSOCIATED IqIdUIDS- Specification of Letters Patent. Patentd Aug. 20, 1918.

Application filed January 22, 1918, .Serial ,No. 2153,2 36.

To all whom it may concern:

Be it known that I, OiIARLES W. MCKIB BEN, a citizen of the United States, residin at Houston, in the county of Harris an State of Texas, have invented certain new and useful vImprovements in Methods of Separating Associated Liquids, of which the following is a specification.

My invention relates to the art of separating associated liquids, in which particles of oneliquid are held, o'rbound in mechanical suspension in another, asin emulsions.

It is especially applicable for the treatment of liquids differing in specific gravity and specific electrical conductivity, such, for 531- ample, as crude petroleum and water.

Oneyof, the especial objects of this particu- Y I 'lar invention is to provide a method of separation of two mechanically associated liquids, such as water and oil when combined in mechanical relation, as in emulsions, by applicationof electric current, in which the 1 current is maintained at all times through the eflect. of surface the liquid to produce {polarization and to prevent entire depolarization of the molecules of the imprisoned water globules when inclosed in oil filaments, and held therein by shrouding oil films.

Another object of my inventionis to provide meanswhereby to prevent thecu-rrent of electricity from increasing in value,

above ,a predetermined fdegree, when the tension of the enpath through the liquid changes in resistf ratus, comprising closed conduits'and recep-- of the followin ance by the interchange of oil and water as the process of separation progresses.

Another object of my invention is to provide a process of separation of entrapped water, from oil, which is continuousarapid,

economical and eflici'ent. 1

Other and further objects of my inve'n tion will become readily apparent, to'persons skilled in theart, from a consideration description when taken in conjunction wit 7 i the drawings, wherein is shown a schematic representation of appae.

tacles by which 'my invention maybe carried into effect. 1

In my cop'en'( ling application for a meth- 0d of separating "associated liquids, filed December 14th, 191.7, andident-ified by Se 'rial- No.', 207,174, I have shown a similar method of procedure inwhich current of-- constanti potential is employed for the purbreaking the enshrouding films that inoloses the water globules. One of the obj ect-ions to such a method is the extremevariation of cur rent value due to the rapid and pronounced -change of electrical resistance in-the path' of the-current,-through the liquid, as the water becomes liberated and displaces the oil, or th e oil emulsion.' When a currentv of electricity, of relatively high potential is employed for this urpose, and the water in' the paths or chalns of globules or streams within the emulsion, substantially short circults the source of current supply, the effect 1s to cause'the current to rise instrength or'value, to such a degree as to practically decompose the water into steam and violently afiect the'source of current supply. In such a procedure the current rapidly varies from maximum to practically zero, due

to short oircuitin and to substantially open circuit, through t 'e liquid,

-When the liberated water in certain strata or streams has substantially displaced the emulsified liquid, the path of the c'urrentis thereby very materially decreased in resistance, substantially short-circuitingthe source of current supply. When the freed water has been precipitated below the path of the current throughthe emulsion, or has been carried by'any means beyond it, and replaced by the emulsified" liquid, or substantially purified oil, the path of resistance is infinitely increased, thereby reducing the current to such an extent as to almost open the circuit. I f

The object of my present invention is to automatically control and maintain .the .current, at all times, in'the emulsion, so that the molecules of water will never at any time be entirely depolarized and soautomatically control the current that its value, under no circumstance, will ever attain a predetermined dangerous degree, This procedure effects a more even and economical result than can be attained by the spasmodic open- .ing of the circuit, as there isno beneficial action during the' -ti'me when'the current is withdrawnyby the unlimited increase of resistance following the. abnormal increase of;

.current, as heretofore Stated. v The physical properties vof heat cause natural repulsion of the molecules of the liquid when. heated, thus diminishing the force of their cohesion, decreasing the viscosity ofthe liquid, and increasing its mopose of polarizin'gthe globples pfwaterand bility. N v

' water and oil, are each subject to or globules constituting this efiect, by increase 'of temperature. When water and oil, such as petroleum, are associated as an emulsion, when heated, the expanslon efiect tends to attenuate the walls of the enshrouding oil filaments, or that which 1111361: venes' between adjoining water globules, and to' decrease their surface tension, therefore, when theemulsion is preliminarily heated,

The particles,

' it is the best or most propitious time to apply electricity to further the efiect or complete the destruction of the oil envelops or films that imprison the myriads of small which mayyary from 135to 180 degrees,

r emulsion through an intense electrical field, produced by a current of electricity,

' pressure,

tendency to cohere,

particles of water, or to so deplete them that they can no longer hold and segregate the many particles of water against their mutual but, yield to the mutual attraction thereof, which effect results in the coalescing of many smaller particles lnto manylarger globules of freewater.

In the practice of myinvention of separation 1 preferably heat the emulsion in a acteristics of the emulsions vary, and, preferably, in a ertical direction, so that part of thefreed ater may. settle, by the efiect some of the freed water may passthrough tom of the tank. a v u .As' the emulsion passes through the to the settling tank'w-ith the oil, and there,

most of the water drops out, or 'is reclpitated, in the course of time, to the ot- 7 treater, or the vertically disposed conduit,

it is subjected to the-actionof a strong electric field, which; produces polarization of the water globules .o r particles, increasing their aflinity for each other, and causing them to strongly approach e'achother by mutual attraction, whereupon the oil is ressed out from between the globules, causing the inclosing walls-tobe come thinner or more attenuate. The resistance of the normallyinterposed oil, being relatively larger than that of the entrapped water, the electric current, which inherently will select I paths of, least resistance, will flow through these globules of water formed into chains or streams bypolarizing effect, where the in-' tervening walls of the oilare thinner, thus in accordance with and as the charinto achamber below the body of the. rapidly movingyemulsion, Because- ;of its great Velocity" through the treater,

intensifying the polarization of the particles 3 along ,the aforesaid paths which further reduces the resistance, by further attenuating the walls, through the tendency of the particles or globules to cohere or reunite into drops or larger bodies or continuing streams of water, until the vigorous upward move ment 'of the liquid, and said cooperating electrical effect, causes rupture'of the inclosing oil filaments surrounding the small particles of water, liberating them, whereupon their. mutual attraction causes .the freed drops to cohere into relatively large con-' glomerate globules or bodies; and some of the water, thus freed, grayitates to the bottom of the'upwardly movlng body of emulsion, out of its path, and intothe settling chamber account of its high velocity, and the high velocity of the moving liquid, is carried over into the settling tank.

Notwithstanding the liquid moving through the separator, the

nascentstreams of water resulting from the 'alined conglomerate globules span the elechigh velocity of the therebelow, but some of the freed water, on

trodes .of the treater and provide such a low resistance pathfor the current of electricity as to amount, substantially, to a short circuit, whereupon the current from a constant potential source, would rise to such huge proportions as to be practically impossible.-

without periodicallyopening the circuit. In my present invention 1 provide means for controlling the current so as to prevent abnormal rise of current, and the consequent opening qf the circuit, as a result thereof, to protect the instrumentality, such as the dynamo or the like, for producing the current by which'the current is maintained constantly in the liquid and prevented from in-. creasing in value beyond a predetermined extent.

By us ng an ordinary transformer to step the current up' from a source ofconstant potential, of a lower electro-motive-force, a reactance c011, of properdlmensions, may be placed in the secondary circuit, which has the effect of preventing the current, in that circuit, from-risingabove a certain.prede-.

termined value proportional to the. react ance' capacity of the coil. The reactance in the secondary circuit does not oppose the current but tends to cause a displacement of the phase between that of the current andthe electro-motive-force. The reaction, therefore, lncreases or tends to increase," as

the current tends to increase, and hence the value of, the current is maintained at, or

prevented from rising to, anfobjectionable and dangerous extent. The effect of this arrangement is such that any tendency for the current'to rise, above a predetermined value, automatically displaces the phase of the electro-motive-force and current to such a degree asto decrease-theefiective electronormal increase of current.

motive-force and consequently prevents abtakes place, automatically, without the ne:

- cessity of suspending the current or open:

ing the circuit, and therefore the particles or molecules of water, to be affected by the current in the manner heretofore described,

are always polarized. and never released or liberated from theirmutual polar-relation.

In my earlier application I have disclosed a method of procedure similar to that included in the present application withthe exception that the current applied to the liquid, for the purpose of separating. the

Water from the oil, is of constant potential character and when the resistance through the liquidbec'omes depreciated to such an extent .as to cause. substantial. short circuit, a

current controlling device must be provided to open the circuit, as a precautionary measuse, to prevent explosion, or mjury to the source of electric current, thereby suspending the operation of thecurrent for a brief period of time and permitting certain quali-. ties of the emulsion to pass through thetreater without having the constituent liquids separated. In this present invention the current is always present and, therefore,

' all of the emulsion that passes through the treater is acted uponin the same manner,

. and to the same extent.

In the present invention I provide; elec- [trodes in the settling chamber and. an electro-responsive device for opening the distaining emulsion to' be treated, which is pumped into the tank through a pipe 6, havmg a downturned end 7 just above a steam heating coil 8, in which the steam may be superheated. A discharge pipe 9, is,pro.-

vided with an upwardly extending part 10,

and a laterally extending end 1 11 having a gas trap cup 12 over the upper end-'13 to prevent, the gases. that may be contained in the upper part of the tank from'escaping through the discharge pipe 9. a The pipe 9 may also have an open end 14 for discharging the emulsion from the body part thereof.

Freed, or entrained water willsettlein the bottom 'part 15 of the tank and be] automatically discharged therefrom. The pipe '9 has a free opening into a vertically-disposed This effect of the globules and conduit or ipe 16 of the treater. The,

upperpart 0 the pipe 16 is surrounded by a relatively large casing 17.' An electric conductor, comprising a' metallic rod 18, is supported in the center of the conduit 15' by an insulating support 19 that isfixed to the top 20 of the treater. The oil, comin g from the pipe 9, will flow upwardly at a relatively high velocity in the conduit 16, of the treater, between the same and the electric conductor 18 and overflow'at thetop 21 into the casing 17. A disch'argeopening 22 is provided above the bottom of the casing 17 and contains a goose neck trap 23. The pipe 24 conducts the relatively pure oilfrom the treater intoa closed oil storage tank 25. A heating'coil.26,.preferably, for super-heated steam, is contained also in the oilstorage tank 25,. and the incoming oil' from the ,treater 17 passes through the-pipe 27 immediately above the heating'coil. The object of putting the heating coil 26 in the oil tank 25 is to maintain the oil at a relatively high temperature to encourage the further separation of any entrapped, o1" free water,

that may be carried over through the treate'r into the oil storage tank, by the coalescenceprecipitation to the bottom of the tank. x

The emulsion treater 17 is fully described.

and claimed in an application Serial No.

203,695 filed by me on the, 24th day of No-' 'vember, 1917. Briefly it consists of the 'arts described, with a settling chamber 30 low the bottomof the inlet to the vertical pipe- 16 and, a discharge pipe 31 leading therefrom, controlled by a valve, operated by an electro-n'iagnet 32. A relay 33-is in circuit with a secondary coil 34v of the transformer which is in inductive relation with through an adjustable resistance 36, is in circuit with the relay coil 37, and witlya. centrally disposed conductor 38 that projects into'the settling chamber 30. The electromagnet 32, controllingthe valve in the discharge pipe 31', is energized bya source of current which may be a. battery .39, or other source.. 3

The centrally disposed conductor 18'of the treater, in the conduit 16, is connected'by a. i wire'40 to the secondary coil 41 of the trans-.-

former including a reactancecoil 142 in series: with the secondary coil and provided with a magnetic core 143', which is adapted to be moved" into and out of the-reactant coils 142, toincrease and decrease the reactance effect of the "coil. The secondary circuitisgrounded, as at 43, and the'pipe 9 is grounded, as at44. The'secondary coil 34 of the transformer 35- is grounded, as at 45. In Fig. 2 I-have shown another constant current transformer of a well'known type,

-possessing.a rather higher power factor and therefore more. eflicient. In either case, i

105 the primary coil 35 thereof arid which,

current dynamo 145.

- high velocity,

counter-electro-nlotive force, or its equivalent, is automatically interposed in the work-- degree, by the formation-0r tendency to form-of chains of globules or streams of water between the electrodes in. the treater.

A constant direct current could be used with a suitable current regulator, but I prefer to use alternating current and thus avoid objections due to electrolysis and gradual disintegration of the electrodes In the operation of-the apparatus the oil will pass from the pressure tank 5, heated as heretofore described and under pressure and through the pipe 9 into-the conduit 16 of the treater between the innerwall of the conduit and the centrally disposed, vertically extending conductor 18, through an intense electrical field produced by an alternating The voltage applied to the electricalfield in this particular case, will depend upon he changing resistance or the interposed liquid electrical conductor. The more water that is interposed between the conductors and the treater, the less will the electro-motive-for e be, it being reduced by the displacement of the phase of electromotive-force and current, as heretofore explained, as a reault of the included reactance in the secondary circuit, and therefore the current will always pass between the central conductor and theinside Walls of the conduit 16 and produce the electric field in a manner clearly understood by persons skilled in the art.

In carryingout my invention, the emulsion passes upwardly through the pipe 16 and overflows at the end 21 of the pipe, at a and as the space between the interior surface of the conduit and the central conductor, is relatively small, with an attendant low resistance, the electro-motive force may be relatively large, and asa result,

the liquid, moving at a relatively high veloc 1ty a very heavy current is peissible with relatively low voltage, because the upwardmovement of the emulsion, through the conduit, will tend to break up the streams or chains of water globules that will be formed by the polarizing eflect r f the current. The

electric field causes, or tends to cause con- 'stant formation of series or chains of polarized=water globules orstreams of water hetween -t' electrodes during the upward movement of theemulsion and these polarized conglomerate globules are rapidly being broken asunder, or disrupted, by the the conduit and the tenacious persistence of the polarizing elfect,'w hile the are under treatment. At the same time, ot er globules,

.ings,

25, so as to' energetic movement of the liquid through mecca? carried over at the top of the conduit, into the chamber 17 and some of it may be carried through the pipe 24 into the settling tank 25, but being freed and present, in relatively large bodies, and no longer comminuted and inclosed by the films of oil,it will be'zpaecipitated to the bottom of the settling tank 25, there to be autcmatically expelled by the apparatus shown at the bottom\of the tank and which has been heretofore' specifically described.

v As the various particles of water are liberated. in the manner heretofore described, they coalesce into larger 'globulesor bodies and as such they ossess a higher specific electrical conductivlty than the emulsion of which they were a part, or than the purified oil. The water th t is contained at the bottom of the receptacle shown in the drawas for instance, in the settling chamber 30, intervenes as a result of their higher 4 between the electrode 38 and I the inner walls of the chamber. This resistance is sufliciently low, by the displacement of the oil, due to the accumulation of the heavier Water therein, the current will then be strong enough in the relay 37 to close the local circuit, to-operate the valvg-moving magnet 32, thereby automatically opening the valve of mitting the water to flow from the settling the discharge pipe 31 and per-.

chamber 30; As the emulsion passes into thesettling chamber 30, following the discharge of the water, the electrical resistance between the central inner surface of the walls of the settling chamber, will be greatly increased, reducing the strength of the current through the relay 33, causing retraction of its tongue, which will open the local circuit and cause the closing of the valve that governs the disdischarged'. as shown, at this-bottom,ofi'the;;tanks 5 and dispose of the accumulation of water that may settle in the bottom-of these receptacles. This particular feature is more completely disclosed in my copending application, to which i been made. Y Y

Emulsions containing petroleum oil have their own individuality, or characteristics,

conductor 38 and the reference has heretofore charge pipe 31. this means the water, freed from the emulsion, is automatically A similar device may be placed,

manifested in variations of viscosity, surface tension, specific gravity, tendency of cohesion, boiling point and electrical conductivity. Some of these effects may be due to the variation in the quality and quantity of the salts contained in the entrapped water and some to other causes.

To provide for adjustment. that maybe required as a result of these differences, the conductor 18, inthe center of the tube or conduit 16, may be adjustably raised or lowered to'vary the surfacesof the confronting,

electrodes requisite for the variation of ,the oil characteristics. By this means the device is made adjustable so as to handle emulsions that come from the tanks, or tank farms or oil direct from the wells, or from the refineries or other oils that may now be otherwise thrown away.

To prevent the gases or vapors that may I be contained in'the upper part of the various containers from escaping, I condense them by-providing a condenser 53 and connect. it.

by pipes 55 to the upper ends of the tank 5 and the treater 17 and by the pipe 51 to the tank 25. The discharge end of the condenser is connected to the pipes 11 for the condensed vapor and purified oil. The interior cooling element within the casing 55,

comprising the headers .56 and 57 and the connecting pipes 58, is to'contain water, at

a relatively low temperature, carried thereto and taken therefrom by pipes 59 and 60.

The oil in the receptacle being hot, it more freely vaporizes and this is an economical means for reclaiming it. I By usmg an absolutely closed system for the treatment of the emulsion, there is no escaping gases that would increase the fire or explosion hazards,-

or other destructive effects, that may arise therefrom, and the system is efiiciently enhanced by being able to condense these gases into purified oil.

In practice, oil coming from the treater into the settling tank 25, is between 135 and 180 degrees R, and the gases distributed at these temperatures readily condense and pass out through the pipe 11. as commercial oil.

While I have herein shown an apparatus by which my invention may be carried into effect, 1t 1s manifest to persons skilled in the art that I am not limited to the peculiar apparatus and'devices shown for the purpose, as my invention consists in the process or steps in the process, for accomplishing the-result described.

.Having described my invention, what I claim is: I

1. Improvements in the art of separatin liquids,in which small particles of one liquid are mechanically suspended in another,

which consists in heating the associated liquids-to a temperature below the boiling point ofthe mixture; passing the liqui through a path between suitably electricallyenergized electrodes, at a velocity sufficient .to prevent the persistance of chains of polarized globules of the entrapped liquid after they have been formed into nascent streams between the electrodes and automatically reducing the effective electro-motive-force of the applied current when the streams begin to form. c 1

2..Improvements in the art of separating liquids, in which small particles of one liquid are mechanically suspended in another, which consists in heating the associated liquids to a temperature below the boiling point .of the mixture; passing the mixture through a path between suitablyelectricallyenergized v electrodes, at a velocity suflicient to prevent the persistance of chains of polarized globules of the entrapped liquid after they have been formed. into nascent streams between the electrodes; automatically re.- ducing the electro-motive-force of the applied current, when the streams begin to CHARLES w. McKIBBEN.- I

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