US2946735A - Oil treating apparatus - Google Patents

Description

July 26, 1960 LE ROI E. HUTCHINGS 2,946,735

on TREATING APPARATUS 2 Sheets-Sheet 1 Filed Aug. 15, 1956 vi l INVENTOR.

LEROI E. HUTCHINGS "f #1 ATTORNEY July 26, 1960 LE ROI E. HUTCHINGS 2,946,735

OIL TREATING APPARATUS Filed 19.56 2 Sheets-Sheet 2 3 lg $15 4 k? a 5 lg ggf L 1 s: Q: o m "L 123 Q In m n o u: s IL g in A] v *2 m E 5 r "Q {Illa 'w 'GF l a INVENTOR. w m 35 LEROI E. nurcuuvss 99 Q ATTORNEY 'torticn and dissociation.

itates nited 2,945,735 on. TREATINGAPPARATUS Le Roi E. Hutchings, Crystal Lake, 111., assignor to The Pure Oil Company, Chicago, 111., a corporation oiOhio Filed Aug. 15, 1956, Ser. No. 604,209

' 3 Claims. (01. 204-302 atent "O Stable emulsions of the water-in-oil type may exist naturally or be produced during refining operations or various chemical treatments or reactions. Resolution of these emulsions by coalescence of the water globules is accomplished only with difficulty. Water droplets of microscopic size are apparently surrounded with an adsorbed film of colloidal asphaltic material or organic salts, depending on the source of the emulsion, which accumulates at the oil-water interface and has little tendency to dissociate. The emulsion-forming film may become coagulated with age and very resistant to mechanical dis- 7 The water droplets are generally saline in natural emulsions as roily oils or may contain organic salts, sultonates, sulfonic acids, unsz'tturated hydrocarbons, etc, and their. inorganic derivatives, in emulsions resulting from chemical treatment or chemical reactions involving oils. The content of water present in these emulsions is variable'and may range up to 80% or more. No distinction is drawn in this specification between watcr-in-oil type emulsions and oil-in-water type emulsions, and reference to the former type of emulsion is meant to be inclusive of the latter.

Emulsions vary in character from closely'spaced or tight emulsions that are more difficult to dissociate and loose emulsions wherein thewater particles are larger and more widely dispersed. Emulsions. from wells operated by gas-lift methods, notably more refractory or tight, as well as emulsions from pumping wells; are included in the scope of the invention. Likewise, emulsions formed of viscous oils and less viscous oils 'are included. The invention also applies to treatment of these emulsions with or without the addition of a modifying agent or electrolyte, along with the application of an induced electrical field of a particular magnitude, although the combination treatment using both the addition of the electrolyte and the electrical field is preferred.

The application of a high differential of electrical potential to an oil emulsion has been explained in theory as causing an induced charge to form on each water particle. The oil phase forms a dielectric medium so that the water particles retain this charge as long as they are under the influence of the field. This electrical charge is in a dipole arrangement causing the water particles to orient in chains between the electrodes. Gradually, either through the alteration of the interfacial tension between the water particles and the oil envelope, or by actual discharge of electrical current or induced concentration of the field along these alincd droplets, there is initiated a progressive coalescing of the particles of water into larger drops which separate from theoil by the influence of gravity. Microscopic examinations during coalescense under the influence of an induced Patented July 2 6, 1960 ice electrical field .have proved this point. Coalescense involves a rupturing of the adsorbed films and the character of these films determines the reaction of the emulsion to electrical or chemical influences. The electrical potential necessary for this purpose depends upon the nature of the absorbed films, the dielectric properties of the oil envelope, theionization potential of the water particles and the distance between the electrodes. Itis common to express the electrical potential in voltage gradients, namely the number of volts applied per linear inch of distance between the electrodes. The voltage gradients may be from 5,000 to 10,000 volts per inch, and as high as 100,000 volts per inch.

To accomplish coalescence of the water particles, various types of electrical demulsifiers have been proposed or are in use. One of the first was the revolvingdisk electrode treater which involves a rather. complicated rotating, raising and lowering system for multidisk parallel plates operating in a vertical column. The horizontal-flow treater employs conical, spaced electrodes between which the emulsion 'flows from center to pee riphery. A rod-type of electrode is used in the concentrated-field demulsifiers and in the double-transformer, concentrated-field type of treater. In some treaters which have no moving parts, short-circuiting is prevented by the rapid flow of emulsion between the electrodes. Each type of treater is best used on a particular kind or viscosity of emulsion. Furthermore, because of the presence ,of air, moving parts, critical spacing of electrodes, or the necessity of intense electrical fields, these previous devices have been expensive, ineflicient and diflicultto operate. This invention is directed to an emulsion breaker of simplified design, simple construction, and, easy operation, which employs a dielectric envelope or conduit to contain the flowing emulsion around a stationary, tubular or rod-like, centrally-located, grounded electrode, which is under the influence of an induced electrical field. i

Accordingly, it becomes a primary object. o'f'this invention to provide an emulsion breaker of simplified design employing a dielectric envelopeto contain the flowing emulsion. a

A second object of the invention is to provide a'method and apparatus for breaking oil emulsions. I

Another objectis to provide an apparatus 'for electrically dissociating oil emulsions within a dielectric en velope influenced by a, central, tubular, grounded electrode whereby short-cir'cuiting is avoided.

Still another object of the invention is to provide a method and apparatus which is capable of breaking oil emulsions under the influence of a strong electrolyte, whereby less electrical current is consumed and shortcircuiting is prevented by the use of an envelope to contain the emulsion, which envelope has strong dielectric properties. 7

Another objectof the invention is to provide a method for dissociating emulsions containing a water phase and oil phase by the application of an electrical field of about 20 to 30 kv. and a frequency of about 1 to. 2 megacycles.

Further objects and advantages of the invention will be described or become apparent as the description proceeds.

The invention is best described by reference to the drawings in which,

Figure l is a longitudinal cross-section of the apparatus with the current source shown diagrammatically.

Figure 2. is a vertical cross-section taken along lines 2-2 of Figure 1. p v

Figure 3 is a flow diagram illustrating the use of the apparatus of this invention. 7 In the drawings-the numeral 10 refersto the main con duit or envelope of dielectric material. Conduit 10 is supported in insulated relationship between pipe-ends 12 and 14 by means of flange pairs 16 and 18, and 20 and 22, in cooperation with insulators 24 and 26. Number 28 refers to a centrally located electrode or conductor supported within, and spaced from, conduit 19 by means of bayonet-type supports 30 and 32. Electrode 10 1s grounded at 34. The emulsion to be treated flows from pipe12, around supports 30 and 32, andinto annular space 36 between the inner wall of conduit 19 and the outer wall of electrode 28. Number 38 refers to a source of electrical current of from 20-30 kv. and 1-2 megacycles Various lead wires, 42, 44, 46, 48, 50 and 52, connect to induction points 54, 56, 58, 60, 62 and 64 which have their tips spaced in fii-inch to l-inch gaps as represented at 66 from the outer wall of conduit 11). Although six induction points are shown, more or less than this number may be used depending on the severity or extent of treatment required for the particular emulsion to be disassociated. The arrangement of bayonettype supports 30 and 32 may also be used at flange pairs 16 and 18 to support electrode 28 at both ends. Electrode 28 may be in the fonn of a rod or tube. If a tubular configuration is used the ends thereof should be plugged so no emulsion flows therethrough.

Power source 38 may comprise a high-frequency coil producing an output current of about 20-30 kilo-volts with a frequency of about 1-2 megacycles from an input of 60 cycles and 115 volts. Other sources of an electrical field may be used, such as a motor-generator or electronic device for the production of same. Induction points 5464 may comprise carbon rods having a pointed or rounded end, or appropriate metal alloys of similar shape. Central electrode 28 may be a steel tube or a solid rod and need not be cylindrical in shape. Similarly, conduit 10 may be any generally tubular configuration, a cylindrical form being the most economical to manufacture. Conduit 10 may be any dielectric material such as glass, plastic, wood, ebonite, hard rubber, amber, Bakelite, mica, etc., which materials have the property of supporting an electric strain and will not communicate an electrical charge from one part to another.

The process is illustrated by the following experiment.

A mixture of ethylene chloride, diisobutylene, and diisobutylene polymers, which resulted from an acid-catalyzed polymerization reaction, was separated from-the acid phase. The acid phase was then washed with hexane and the resulting hexane phase was added to the above mixture. The mixture consisted of 300 g. of ethylene chloride, 109 g. of polymers, and 321 cc. of hexane. These combined liquids were placed in a separatory funnel and washed twice with sodium hydroxide solunected to wash tower 122 by line 124 and said wash tower is equipped'with lower inlet 126 and drain 128. Line 130 connects with line 132 from compartment 118 of settler 112 to convey products to wash tower 134, having inlet 136, drain 138 and outlet 140. Branch line 142 connects with outlet 141 Emulsion breaker 10 is connected to line 140 and outlet 144 leading to settler 146 having a baffle 148 which maintains liquid level 150. Settler 146 has drain 152 and outlet 154, the latter connecting to drier 156, having outlet 158. Branch line 160 connects to line 154. I

The operation of the process as applied to the polymerization of diisobutylene may be as follows: 96% sulfuric acid is pumped through line IGZ-and ethylene chlo- .umes of diisobutylene previously introduced in'reaction tion. The emulsions which formed during. each of these washing steps were broken by inserting a grounded wire into the emulsion and applying a high-voltage, high-frequency current to the separatory funnel with a coil of properties as described above. The washed, neutralized liquids were then washed three times with a 10% sodium sulfate solution, again breaking the emulsions as above. It was found that sodium sulfate solutions containing as little as 1% sodium sulfate also were effective in aiding the emulsion breaking, but a larger amount of water remained in the hydrocarbon phase. The purified hydrocarbon phase was then dried by percolation through anhydrous calcium sulfate. J

' The use of apparatus may be also illustrated by referenceto Figure 3 as applied to the polymerization of diiso-. butylene. In Figure 3, the numeral 1110 refers to a reaction vessel having inlet line 102, branch line 104 connected thereto and inlet line 1116 all communicating withthe top of the vessel. Reaction vessel 100 is equipped with a stirrer indicated at 108. Outlet line 110 leads to settler 112 shown in cross-section to illustrate battle vessel 100. The initial mixing is conducted slowly with cooling. Following the start-up, the reaction vessel is heated to about 50 C. and maintained at this temperature. Withdrawal of the reaction mixture at line is then begun at such a rate as to maintain a residence time of about 1 hour in vessel 1% and a balance of reaction mixture therein. The mixture passes through line 110 to settler 112 wherein the acid phase readily separates from the hydrocarbon-ethylene chloride phase. The acid phase is withdrawn from settler 112 via line 124 to wash tower 122 wherein it is washed by an upward stream of ethylene chloride entering at line 126 which removes any hydrocarbons contained therein via line 130 to Wash tower 134. A portion of the recovered acid phase from line 128 may be recycled to line 102, although discard of the main portion is practiced to prevent any build-up of impurities. About one volume of ethyl-- ene chloride per volume of acid phase is used in wash tower 122. The ethylene chloride solvent may be recovered from the recovered acid phase by distillation. The top hydrocarbon-ethylene chloride phase spills over baffle 114 and is drawn 011 by line 132 to mix with the ethylene chloride-hydrocarbon mixture in line 130. In wash tower 134 this combined mixture is washed with 5% aqueous sodium hydroxide solution introduced at line 136. About one volume of sodium hydroxide solution is used per 3 volumes of combined mixture sent to tower 134. Within tower 134 any remaining acid is neutralized and the spent hydroxide is withdrawn at line 135, and portions thereof may be recycled to line 13 6.

An emulsion of water containing some sodium sulfate and the polymer product leaves tower 134 via line and passes through emulsion breaker 11D, constructed as shown in Figures 1 and 2. A concentrated solution of sodium sulfate may be introduced at branch line 142 to aid in breaking the emulsion. For this purpose a sufficient quantity of concentrated aqueous sodium sulfate solution is added to bring the total concentration thereof in the emulsion to at least about 1.0%. In some instances the addition of sodium sulfate at this point may be omitted.

Although only one emulsion breaker is shown in Figure 3, more-than one maybe used depending on their size and the amount of emulsion to be treated. Where two or more emulsion breakers are used they may be connected in series or in parallel flow between lines 140 and 144. The flow rate through any one emulsion breaker should be such that the Reynolds number as calculated for the annular space 36 and the adjacent electrode 23 and line 144 leading to settler 146 should be no greater than 500'. This means that viscous or laminar flow must be maintained.- After passing through emulsion breaker iilthe product is sent via line 144 to settler 146 for completion of the separation. Part of the water phase withdrawn at line 152 may be recycled if additional electrolyte'is added at line 142. The hydrocarbon phase containing the polymerproduct spills over baflie 148 and is sent to drier 156.

drying or distillation, the ethylene chloride solvent is recovered along with diisobutylene for recycling and the polymer product remains. Either glass-lined vessels or a type of steel alloy resistant to concentrated sulfuric acid is used in all construction prior to tower 134. Normal materials of construction are used in the balance of the apparatus.

For commercial application of my invention, the emulsion containing an efiective amount of electrolyte is passed through a section of glass (or other, electrically non-conductive) pipe, inside of which is a grounded concentric pipe, so that the liquid passes through the annulus so formed. The high-frequency current is applied at several points along the glass pipe, the number of such points being dependent upon rate of flow, emulsion stability, and amountv of electrolyte in the water phase. After flowing through my emulsion-breaker, the separated materials are immediately passed into a conventional settling tank at or near the phase interface in the tank.

What is claimed is:

1. An apparatus for dissociating oil emulsions comprising in combination a hollow tubular dielectric envelope, a grounded electrode within and spaced from the sides of said envelope toform an unobstructed annular space therebetween, means for supporting said envelope as a section between the open ends of a conduit, said conduit supplying emulsion to one end of said annular space and removing treated emulsion from the other end thereof, at least two bayonet supports extending from the inner side of said conduit and attaching to said grounded electrode, means for grounding said conduit, means for supplying high-frequency alternating current to said grounded elec trode, means for applying said alternating current to said concentric envelope, electrode and annular space including a plurality of conductive rods, said rods being radially positioned and spaced from the outside of said envelope by a gap of about A to 1 inch, and leads connecting each of said rods to said source of alternating current.

2. An apparatus for dissociating oil emulsions comprising, in combination, a hollow tubular dielectric envelope,

an elongated electrode within and spaced from the sides of said envelope to form an unobstructed annular space therebetween, means for supporting said envelope'as a part of a continuous unobstructed flow path between the opposed spaced open ends of a conduit, said conduit supplying emulsion to one end of said envelope and removing treated emulsion from the other end thereof, means for electrically insulating said envelope from said support means, one end of said electrode extending within one of the open ends of said conduit, bayonet supports extending from the inner side of said conduit and attaching to said extended end of said electrode, means for grounding said electrode, means for supplying a highfrequency alternating current to said elongated electrode, means for applying said alternating current to said concentric envelope, electrode and annular space including a plurality of conductive rods, said rods being radiallypositioned and spaced from the outside of said envelope by a gap of about A to 1 inch, and leads connecting each of said rods to said source of alternating current.

3. An apparatus for dissociating oil emulsions comprising, in combination, a hollow tubular dielectric envelope, an elongated electrode within and spaced from the sides of said envelope to form an unobstructed annular space therebetween, flange means at each end of said envelope, an electrical insulator between said flange means and said envelope, opposing flange means on the spaced ends of a conduit whereby said envelope is supported with said annular space as a part of a continuous unobstructed flow path between said spacedends of said conduit, said conduit supplying emulsion to one end of said annular tended end ofsaid electrode, means for grounding said electrode, means for supplying high-frequency alternating .current to said elongated electrode, means for applyingsaidalternating current to said concentric envelope, electrode and annular space including a plurality of conductive rods, said rods being radially positioned and spaced from the outside of said envelope by a gap of about M: a to limb, and leads connecting each of said rods to said source of alternating current.

References Cited in the file of this patent UNITED STATES PATENTS 1,533,711

7 OTHER REFERENCES US. Bureau of Mines Bulletin 250, 1926, page 45.

Claims (1)

1. AN APPARATUS FOR DISSOCIATING OIL EMULSIONS COMPRISING IN COMBINATION A HOLLOW TUBULAR DIELECTRIC ENVELOPE, A GROUNDED ELECTRODE WITHIN SAND SPACED FROM THE SIDES OF SAID ENVELOPE TO FORM AN UNOBSTRUCTED ANNULAR SPACE THEREBETWEEN, MEANS FOR SUPPORTING SAID ENVELOPE AS A SECTION BETWEEN THE OPEN ENDS OF A CONDUIT, SAID CONDUIT SUPPLYING EMULSION TO ONE END OF SAID ANNULAR SPACE AND REMOVING TREATED EMULSION FROM THE OTHER END THEREOF, AT LEAST TWO BAYONET SUPPORTS EXTENDING FROM THE INNER SIDE OF SAID CONDUIT AND ATTACHING TO SAID GROUNDED ELECTRODE, MEANS FOR GROUNDING SAID CONDUIT, MEANS FOR SUPPLYING HIGH-FREQUENCY ALTERNATING CURRENT TO SAID GROUNDED ELECTRODE, MEANS FOR APPLYING SAID ALTERNATING CURRENT TO SAID CONCENTRIC ENVELOPE, ELECTRODE AND ANNULAR SPACE INCLUDING A PLURALITY OF CONDUCTIVE RODS, SAID RODS BEING RADIALLY POSITIONED AND SPACED FROM THE OUTSIDE OF SAID ENVELOPE BY A GAP OF ABOUT 1/4 TO 1 INCH, AND LEADS CONNECTING EACH OF SAID RODS TO SAID SOURCE OF ALTERNATING CURRENT.

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