US2420687A - Dehydration of emulsions - Google Patents

Description

MayZO, 1947. A. D. SMALL 2,420,687

DEHYDRATION OF EMULSIONS Filed Dec. 21, 1942 Fig.1.

EMULSION INLET Fig 2.

3mm f g I Arf/zun D Smal/ 7/%W ilwm/v Patented May 20, 1947 DEHYDRATION OF EMULSIONS Arthur D. Small, United States Army, Washington, D.

Application December 21, 1942, Serial N 0. 469,729

1 Claim.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein ma be manufactured and used by or for the Government for governmental purposes, without payment to me of any royalty thereon.

This application is a continuation-in-part of my copending application Serial No. 433,928, filed March 9, 1942, and relates to a process for dehydrating emulsions. More particularly, it relates to a process for separating the oil and water particles present in the emulsion produced from oil reservoirs.

It is an object of this invention to provide a method for rendering such separation more expeditious and to provide means whereby the process may be carried out with a minimum of time and effort.

It is a further object of this invention to provide apparatus for carrying out the process described which will be of simple construction and considerably cheaper than present day apparatus, and in which maintenance requirements will be a minimum.

These and other objects'and advantages of my invention will become apparent upon a consideration of the following detailed description when taken in conjunction with the accompanying drawing, in which:

Fig. l'is a longitudinal view, partly in cross section, of the separator and its associated apparatus; and

Fig. 2 is a front view of the separator.

Emulsion produced from oil reservoirs consists of minute globules of salt water surrounded by crude oil. It is apparent that, in order to dehydrate the emulsion, it is necessary to break or destroy the oil films which enclose and separate the small water globules, so that they may coalesce and form larger globules on which ravity may have a greater influence in bringing about settling, The force which opposes this agglomeration of water particles can be resolved into terms of differential surface tension and the negative electrical charge of the water particles.

Instead of depending solely upon such agencies as heat, chemicals, high potential electrical discharges or the like for such separation, I employ mechanical vibrations combined with an electrical discharge. In vibrating the emulsion at a high rate which effects a rapid compression and decompression'of the fluid, it is believed, in the light of tests made with the subject apparatus. that, because of the relative incompressibility of the Water and the compressibility of the crude oil, the vibration breaks the oil film surrounding the water globules, thereby allowing them to unite as larger globules producing a final separation of the crude oil and salt water. In order to further expedite the coalescence of the water globules, an electrical discharge is maintained at the point of maximum compression of the emulsified fluid to eiTect neutralization of the electrical charge carried by the particles of the dispersed phase of the emulsion. For carrying out the above described principles, I have designed the apparatus illustrated.

Referring to the drawing, it will be seen that I have provided a relatively thick brass ring I l as the main body of the separator. The inside of the ring I! is countersunk on each side in order to take the flange rings 8 and 9 which hold the glass plate I and the steel vibrating plate 6, respectively. in place. The flanges 8 and 9 are fastened to the main brass ring II with screws 5, thereby forming a container in which the dehydration of the crude oil takes place. The emulsiflfid oil is supplied to the center of the container by means of inlet 1 The separated oil is discharged from the upper outlet 14 and the water is discharged through an outlet l5 which extends within the container to a position near the bottom thereof, The entire assembly is mounted on suppo ting block :1 which in turn is mounted upon the base It.

Referring more particularly to Fig. 1, the following apparatus is provided to generate the necessary vibration of the steel plate 6. A screw 22 is attached to the center of the steel plate 6 and engages one arm of a V-frame l9 movable on the axle 20 which in turn is mounted in pillow block 2!. The other arm of the V-frame l9 carries a small wheel 25 arranged to be actuated by the hexagonal cam 26 carried on axle 21 mounted on pillow block 3 I. The axle 21, together with the cam 25, is driven by the motor 28 through pulleys 20 and 30 and the belt 32.

To set up the apparatus for operation, the screw 22 is manipulated so that the proper clearance exists between the cam wheel 25 and the hexagonal cam 26 and then the lock-nut 23 on the screw 22 is tightened to maintain the apparatus in the adjusted position. In order to smooth out the operation of the apparatus and to eliminate back lash. a spring 24 is connected between the V-frame I 9 and the supporting block l1. With the apparatus so adjusted, rotation of the hexagonal cam 25 will cause an oscillating movement of the V-frame which in turn will vibrate the steel plate 6. I have found that a vibration rate between 10,000 to 20,000 cycles per second is most effective in causing the separation of the oil and Water particles.

In order to provide for a suitable electrical discharge through the emulsified oil so that the electrical charge of the water particles may be removed and their coalescence aided, I have provided in the center of the glass plate I an electrode l3 having its discharge end l3 situated immediately in advance of outlet l2 as clearly shown in Fig. 1 of the drawings. Electrode I3 is connected to a source of potential which is variable from approximately 3,000 to 5,000 volts and which will maintain a current flow from 1 to 10 amperes, the particular voltage and current requirements being dependent upon the specific gravity of the crude oil. The return Path to the source of potential energy is brought out from a suitable contact on the brass ring I I. Since the electrode [3 does not come in contact with any metal part of the separator, the current follows a path through the emulsion and in so doing removes the negative electrical charge which normally exists on the water particles.

Separation of the oil and water being effected as a result of the combined effect of the mechan ical vibration and the removal of the negative charge on the water particles as described above, the oil being lighter than the water will collect in the upper half of the container and the water will settle to the lower half where they may be readily drawn off by means of outlets l4 and 15, respectively.

While I have described my invention with particularity, it is to be understood that I do not wish to be limited to the particular details and arrangements disclosed since various modifications within the spirit of the invention will suggest themselves to one skilled in the art.

Having described my invention, what I claim as new and wish to secure by Letters Patent is:

An apparatus of the continuous flow type for separating the phases of an emulsion comprising a dehydrator including opposed diaphragms spaced to define a narrow treating chamber, one of said diaphragms being formed of an insulating material, the other of metal, means for delivering a supply of emulsion to said treating chamber, said means including a supply conduit extending from a source of emulsion supply to the interior of said chamber and terminating with its outlet orifice disposed between and approximately centrally of said diaphragms, means attached to the center of said metallic diaphragm for imparting vibratory movement thereto for the purpose of effecting rarefaction and condensation of the constituent particles of the emulsion, an electrode mounted in said diaphragm of insulating material and provided with a discharge end disposed immediately in advance of said outlet orifice, said discharge end being spaced from the center of said metallic diaphragm whereby to form an electrical discharge area across the mouth of said outlet orifice, means in electrical relation with said electrode and said metallic diaphragm for establishing a difference of potential between said electrode discharge end and said metallic diaphragm and across said discharge area, whereby, as said emulsion emerges from said outlet orifice and enters the discharge area extending thereacross, the intensity of the electrical field in said area in connection with the condensation and rarefaction action of said vibratory diaphragm efiects coalescence of the water phase of said emulsion into masses which will collect in the lower portion of said treating chamber beneath the oil phase therein, and means in connection with said dehydrator for separately removing the oil and water phases of the emulsion as the respective masses thereof collect in the upper and lower portions of said treating chamber whereby to provide an uninterrupted flow through said chamber.

ARTHUR D. SMALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,828,847 Lawrason Dec. 29, 1931 1,942,480 Lawrason Jan. 9, 1934 1,591,472 De Brey July 6, 1926 1,394,462 Alden et a1 Oct. 18, 1921 2,300,761 Amy Nov. 3, 1942 2,257,997 Barnes Oct. 7, 1941 1,781,076 Palmer Nov. 11, 1930 1,430,294 Eddy et a1. Sept. 26, 1942 2,138,051 Williams Nov. 29, 1938 2,170,178 Williams Aug. 22, 1939 2,083,798 Roberts June 15, 1937 2,033,418 Eddy Mar. 10, 1936 2,061,197 Kiech Nov. 17, 1936 OTHER REFERENCES Piersol-,Electrical Condenser Process for Demulsifying OilState of Illinois, Department of Registration and Education, Report of Investigations, No. 29, page 16 (1933).

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