URBANA I ILLINOIS STATE U" '41 1& A 'CP a b .00 .01 .02mm, I . I I SCALE Fig. A — Photomicrograph showing emulsified oil (a) untreated and (b) treated electrically for one minute. The equipment used is shown in Figure 1. ELECTRIC CONDENSER PROCESS 19 The diameter of the emulsified droplets before treatment (Fig. 4, a) is of the order of approximately 1/100 of the distance between lines on the scale or 0.000004 inch. The high magnification was necessary to show the individual emulsified particles of water. Figure 4 b shows the water globules increased in size due to condensation by coalescence, after being subjected to an electric field for one minute. The second stage of dehydration in which the field has been applied for two •». *-w 'X?.' ''«\*>VJ .A3*./ .«- , 5. F £ V;.-. „.-,.';' " #-^^1^:£%;-v ^o <*-» °<* *■.* /?. -; .(• ■-•V^?Ai:»i/B"" A.,^ '* ' ■: ..' ^ j * - # ■ x* . <*», b ' SCALE FlG. 5 — Photomicrograph showing emulsified oil after electrical treatment last- ing (a) two minutes, (b) four minutes, (c) five minutes, and (d) six min- utes. 20 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYING OIL .00 .01 I l_ .02 .03 mm. SCALE Fig. 6 — Photomicrograph showing emulsified oil after eight minutes electrical treatment. The water globule is 125 million times the size of those in the original emulsion. minutes is shown in figure 5 a. The magnification is reduced to about 1/5 that of the previous scale. The influence of a field for four minutes is shown in figure 5 b. Some of the globules have a diameter of approximately the width of a scale spacing. Four minutes is apparently the shortest period effective in breaking down an emulsion to large enough particles so that the water settles rapidly under the influence of gravity. Oil shown in figure 5c was treated for five minutes and that shown in fig- ure 5d for six minutes. The latter shows two large globules whose boundary films have been broken down and which are in the process of coalescing. Direct- ly below them are shown two globules coming together but whose boundary films have not yet been ruptured. The effect of the electric field over a period of 8 minutes is shown in fig- ure 6. The oil is practically free from the smaller water globules and the large globule shown is approximately 5 scale spacings in diameter, or about 500 times the diameter of the average water globule before treatment. As the volume ratio of two particles equals the ratio of the cubes of the diameters, it is evident that the large globule is 125 million times the size of the original emulsion globules. METHOD OF WATER DETERMINATION Centrifuge tests were made to determine the water content both before and after treatment of emulsified oil from repressured properties of the Tidewater Oil Company. The centrifuge used was the large electrically driven Babcock ELECTRIC CONDENSER PROCESS 21 type which is used for testing milk. The centrifuge has a radius arm six inches long. A readjustment of the rheostat to increase the speed from 2200 to 2500 revolutions per minute resulted in no additional removal of water. The higher speed is not satisfactory for testing purposes, due to the fact that the centrifugal 15 20 TIME (MINUTES) Fig. 7 — Graph showing time-rate reduction of water in emulsified oil, con- taining initially 1.1 per cent water, when treated in centrifuge at a temperature of 80° F. force is great enough to cause breakage of the glass centrifuge tubes. The tubes are the standard tubes used by the American Society for Testing Materials. They hold 100 cc. and are tapered at the lower end with calibration reading directly to 0.1 cc. or one-tenth of one per cent. The centrifuge tests made in this investigation used a centrifugal force two or three times as high as those in standard field practice as described by D. B. Dow in Bulletin No. 250 of the U. S. Bureau of Mines, p. 6: "The tubes are . . . placed in the centrifuge, which revolves at high speed for 2 to 10 minutes, depending upon the oil and the speed of the centrifuge. The latter is ordinarily about 1500 r.p.m." Figure 7 shows the results of centrifuging, for various periods, portions from the same sample of emulsified oil which contained 1.1 per cent water before cen- trifuging. The ordinate percentages are of the total emulsified water, thai is 100 per cent in the graph represents no removal of water. These tests weir made at a temperature of 80° F. 22 ELECTRIC CONDENSER PROCESS FOR DEMULSII' YING OIL LABORATORY TESTS ON ELECTRIC CONDENSER DEHYDRATION OF ILLINOIS OIL In selecting samples of cut oil for use in laboratory tests of electric condenser dehydration, it was attempted to secure them from areas in which most difficulty is experienced in dehydration. Two sets of 5-gallon samples of emulsion from stock tanks on repressured properties were furnished to the Survey by the Tidewater Oil Company and one by the Ohio Oil Company. Two hundred tests of electric condenser dehydration were made on these three different emulsified oils. Typical results are presented in Tables 1, 2, and 3. TESTS WITH PARALLEL ELECTRODES Table 1 records the results of dehydration for various durations of treat- ment of emulsions which contained various percentages of water before treatment. A sample of oil field emulsion in a 5-gallon can was allowed to stand for several days. From various levels in this can samples were pipetted into 2-litre flasks. Each sample was allowed to settle for 12 hours and any free water that had been pipetted was discarded. The sample was then divided into two parts, one of which was tested by centrifuge for per cent of emulsified water, and the other subjected to electric treatment. In this experiment an induction coil was operated at 6 volts and 2 amperes from an automobile battery. The three glass test tubes 0.8 inch in diameter and about 6 inches high which contained the oil were placed between the two parallel metallic electrodes spaced 0.9 inch apart. In parallel circuit with the electrode Table 1. — Results of laboratory tests on electric condenser dehydration of crude oil at 80° F. Oil in glass tubes between parallel electrodes Treated emulsion Per cent Water in untreated emulsion A Time treated (minutes) Stirred during treatment Per cent water after Not stirred during treatment Per cent water after settling 24 hours settling 24 hours 4.4 2 0.4 4.2 4 — 0.2 3.2 5 0.2 — 10.0 5 0.5 — 4.0 6 — 0.1 2.0 8 — 0.1 6.0 10 — 0.1 3.2 10 0.2 — 4.8 10 0.2 — 6.5 10 0.4 — 10.0 10 0.5 — a The percentage of water in the untreated emulsion was the amount after the emulsion had settled 12 hours and just before treatment. ELECTRIC CONDENSER PROCESS 23 was a 0.5 inch spark gap. The oil was stirred slowly by hand with a glass rod while being subjected to the potential field. A Model T Ford spark coil with an interrupter frequency of approximately 60 vibrations per second was used, but due to the series of overtone frequencies, the effective frequency is always greater than the mechanical frequency. Results for identical experimental conditions, with the exception that the oil was not stirred during electrical treatment are also shown in Table 1. Appar- ently there is no advantage in stirring the oil during treatment. A blank test, Fig. 8 — One sample of untreated (left) and three samples of treated emulsified oil. without electric treatment on an emulsion containing 3.2 per cent water, showed that 3.0 per cent water remained in the oil after settling for 24 hours subsequent to the time of treatment of other samples. This compares to a maximum of 0.5 per cent water with electrical treatment and indicates that in this particular oil, treatment, other than settling, is necessary to break down the emulsion. Figure 8 shows three samples of treated oil to the right, in which the water has settled out, and one of untreated oil, left, which shows no settling after eighl months. All are parts of the same original sample. 24 ELECTRIC CONDENSER PROCESS FOR DEMUI.SIFYING OIL A series of tests was made to ascertain the influence of temperature on the efficiency of electrical dehydration (Fig. 9). All tests were on portions of the same sample which contained 3.4 per cent emulsified water. The ordinate of each point represents the percentage of emulsified water remaining after electrical treatment for five minutes at the temperature shown by the abscissa. The three intermediate points represent single tests; the end points represent the mean of duplicate tests. The extrapolated portion of the curve, shown by a dashed line, is based on viscosity. 90 100 110" 70" 60' TEMPERATURE F Fig. 9 — Graph showing effect of temperature of treatment on dehydration of crude oil. All tests were on portions of the same sample which contained 3.4 per cent water. The treatment was for five minutes for each test. This curve indicates clearly that the efficiency of electrical treatment increases at higher temperatures and decreases rapidly at lower temperatures although 80° F. is satisfactory for all Illinois oils tested when time of treatment is ade- quate. The essential feature of electrical dehydration consists of the coalescence of water globules due to their movement under the influence of an alternating field, but at low temperatures the increased viscosity of crude oil interferes with the free movement of the charged globules, until at the point of congealing all movement is prevented. It is to be expected that a less viscous oil may be treated at a lower temperature than is permissible with oils of greater viscosity. For each crude oil it is necessary to determine experimentally the optimum temperature for dehydration and settling. In order to avoid unnecessary heat- ELECTRIC CONDENSER PROCESS 25 ing in winter time, it is desirable to determine the lowest temperature at which the water can be reduced to the percentage necessary to meet pipe line and re- finery specifications. TESTS WITH PARALLEL ELECTRODES USING CONTINUOUS FLOW A series of electric dehydration tests were made under continuous flow con- ditions in the equipment shown in figure 1. These tests were on parts of the sec- ond lot of emulsified oil from repressured properties of the Tidewater Oil Com- pany. Table 2 shows results for periods of treatment from 5 to 10 minutes on samples containing from 2.6 to 6 per cent water. All tests were made at a tem- perature of 80° F. The general procedure of sampling was the same as that de- scribed on page 22. Table 2 — Results of laboratory tests on continuous flow condenser dehydration of crude oil at 80° F. (Fiy. 1) Per cent water in untreated emulsion a 5.0 5.0 5.0 6.0 6.0 6.0 6.0 2.6 Treated Emulsion Time treated Per cent water (minutes) after settling 24 hrs. 5 0.4 5 0.4 5 0.2 8 0.3 10 0.4 10 0.3 10 0.4 10 0.5 a The percentage of water in the untreated emulsion was the amount after the emul- sion had settled 12 hours and just before treatment. TESTS WITH CONCENTRIC ELECTRODES Table 3 — Results of laboratory tests on electric condenser dehydration of crude oil at SO" F. Oil between concentric electrodes (laboratory unit), not flowing Per cent water in untreated sample a Treated Emulsion Time (minutes) Per cent water after settling 24 hrs. 1.8 1.8 1.1 0.8 1.8 2 4 4 4 6 0.4 0.3 0.2 0.1 0.3 a The percentage of water in the untreated emulsion was the amount after the i sion had settled 12 hours and just before treatment. Table 3 gives the results for a concentric electrode dehydration unit as pre viously described except that the laboratory unit consisted of onl\ one .vtoni 26 ELECTRIC CONDENSER PROCESS FOR DEMUI.SIFYING OIL tube. The tests were on emulsified oil from repressured properties of the Ohio Oil Company and were sampled as described on page 22. The results indicate that the concentric electrodes are as effective as the parallel electrodes in reduc- ing the percentage of water below the permissible limit. FIELD TESTS The field unit (Fig. 3) was used in the field to make dehydration tests on emulsified oil from repressured properties of the Tidewater Oil Company and Ohio Oil Company. The samples were dipped out in 3-gallon buckets from near the surface of oil in the stock tank which had been standing for several days. The emulsified oil was divided into two parts, one of which was centrifuged later in the laboratory and the other electrically treated in the field unit. The results of tests made at the Tidewater Oil Company Repressuring Plant No. 3, north of Robinson, Illinois, are given in Table 4. Table A — Results of field tests on electric condenser dehydration of crude oil at properties of the Tidewater Oil Company Oil between concentric electrodes (field unit, Fig. 3), not flowing. Lease Cox Cox Cox Cox Lloyd-Black Lloyd-Black Lloyd-Black Lloyd Per cent water in untreated sample * 1.9 1.9 0.6 0.6 2.2 2.2 2.2 0.2 Treated Emulsion Time treated (minutes) Per cent water after settling 24 hrs. 0.3 0.2 0.2 0.1 0.1 0.1 0.1 0.0 a The percentage of water in the untreated emulsion was the amount after the emul- sion had settled 12 hours and just before treatment. Samples from the M. Newlin and Ed. Simpson leases were from oil that had not settled. They were taken from the gunbarrel tanks, and showed water contents of 44 and 72 per cent, respectively. After electrical treatment for four minutes and settling for 24 hours the water contents were 1.6 and 3.6 per cent, respectively. This shows the necessity for permitting the free water to settle out before electrical treatment. Results of the field tests made on badly emulsified oils taken from various repressured properties of the Ohio Oil Company near Robinson, Illinois, are shown in Table 5. It may be noted that in all cases where adequate time of treat- ment (minimum 4 minutes) has been given the results meet pipe line specifica- tions as contrasted to exceedingly high values for the settled oil which had not been treated. ELECTRIC CONDENSER PROCESS 27 Table 5 — Results of field tests on electric condenser dehydration of crude oil at properties of the Ohio Oil Company Oil between concentric electrodes (field unit, Fig. 3), not flowing. Lease A Per cent water in untreated emulsion B Treated Emulsion Settled Time treated (minutes) per cent water after settling 24 hrs. 60 hrs., untreated J. H. Wood No. 23 J. H. Wood No. 23 J. H. Wood No. 23 J. H. Wood Nos. 23-25 J. H. Wood Nos. 23-25 J. H. Wood Nos. 23-25 E. A. Cortelyou No. 3 E. A. Cortelyou No. 3 E. A. Cortelyou No. 3 C. S. Jones 18.0 18.0 18.0 5.0 5.0 5.0 37.0 37.0 37.0 0.7 0.7 0.7 2 4 6 2 4 6 2 4 6 2 4 6 0.8 0.6 0.5 0.6 0.5 0.4 0.4 0.2 0.1 0.3 0.2 0.1 3.0 3.0 3.0 1.1 1.1 1.1 1.6 1.6 1.6 0.6 C. S. Jones C. S. Jones 0.6 0.6 AThe location of leases in Crawford County is: J. H. Wood, sec. 33, T. 7 N., R. 13 W. E. A. Cortelyou, sec. 28, T. 7 N., R. 13 W. C. S. Jones, sec. 9, T. 7 N., R. 12 W. b The percentage of water in the untreated emulsion was the amount after the emul- sion had settled 12 hours and just before treatment. ELECTRIC CONDENSER PROCESS FOR DEMUI.SIFYING Oil. Fig. 10 — Diagram showing elevation and plan of suggested lay-out for commercial in- stallation of electric condenser dehydrator. ACKNOWLEDGMENT 29 Commercial Installation It is believed that the electric condenser dehydrator can be installed on many leases in such a way as to make use of existing tankage and equipment. A sug- gested plan for a field lay-out is illustrated in figure 10 and is described in the following paragraphs. It is realized that this plan is not necessarily suited to all cases and that modification to suit individual needs may be necessary. The hookup of the electric condenser dehydrator with the customary layout of gun-barrel and shipping tanks is shown in figure 10. No change at all is needed within the gun-barrel separating tank. The dehydrator can be installed between the gun-barrel and the stock tank by inserting a stop at the end of the pipe from the gun-barrel tank and connect- ing the pipe to the dehydrator behind this stop. In summer this stop is kept closed and the oil flows from the gun-barrel tank through the dehydrator and into the summer stock tank as shown in figure 10 (elevation). In winter a third tank is needed and if it is buried, as shown, the dehydration can still take place under gravity flow. Oil is run into the summer stock tank and heated, then run to the dehydrator through a pipe connected near the bottom of the summer stock tank (shown in plan but not in elevation). This pipe is fitted with a stop to control the flow of oil through the dehydrator and into the buried stock tank. From the buried tank the oil can be pumped, either by hand or by a jack from the power, into the shipping tank. ACKNOWLEDGMENTS The Survey has received assistance from Mr. W. S. Corwin, Mr. Robert Brown, and Mr. Mark Kennefecke, all of the Tidewater Oil Company, and Mr. J. K. Kerr, Mr. C. C. Carroll, Mr. William McCaman, and Mr. M. H. Flood, all of the Ohio Oil Company, who have cooperated in making field tests and in providing samples of emulsified oil for laboratory research. The following members of the Survey staff also assisted in carrying out the research and in the preparation of the report: Mr. H. C. Roberts and Mr. J. M. Nash, Physics Assistants, made the dehydration tests; Dr. R. E. Grim, Petrog- rapher, assisted in microscopic interpretation; Dr. A. H. Bell, Geologist and Head of the Oil and Gas Division, and Mr. Frederick Squires, Associate Engin- eer, who have accompanied the writer on visits to the oil field, have contributed valuable suggestions; and Dr. M. M. Leighton, Chief, lias brought to realization the present program of research. 30 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYINC Oil. BIBLIOGRAPHY Abozeid, Microscopic study of California oil-field emulsions. Trans. A. I. M. E., Petro- leum Division, p. 340, 1931. California emulsions are water-in-oi! type. Certain emulsified particles are found to contain salt crystals. Alden, S. F., and Eddy, H. C, Process and apparatus for refining liquid mixtures, U. S. Patent No. 1,394,462, Oct. 18, 1921. Describes the use of cyclic increasing and decreasing potentials to guard against electrical break down. Alexander, Jerome, Colloid chemistry, vol. 3. The Chemical Catalog Company, Inc., New York. The nature of emulsions from the chemical standpoint. Ayers, E. E., Common characteristics of crude petroleum emulsions. Jour. Ind. & Eng. Chem., vol. 13, p. 1011, Nov., 1921. Discussion of methods of break-down of emulsions by heat, gravity, centrifuge, chemicals, and use of Cottrell's "Wetted Septum." Bancroft, W. D., Applied colloid chemistry, p. 362, 3rd Edition. McGraw-Hill Book Company, 1932. Theory of formation, structure, and break-down of emulsions from the stand- point of physical and colloid chemistry. Beazley, A. T., Electrical dehydration of crude petroleum. Western Eng., vol. 1, p. 56, Apr., 1912. Discusses field operation of Cottrell process. Bom, S., Oil field practice in handling crude oil emulsions. Jour. Ind. & Eng. Chem., vol. 13, p. 1013, Nov., 1921. Describes steaming plant, Cottrell process, chemical treatment, and centrifugal method. Bright, R. T., Treating oil by use of chemicals. Oil and Gas Journal, vol. 28, p. 40, June 20, 1929. Describes use of chemicals in plant practice. Chatfield, J. C, Steam treated separators used to take out water in Panhandle crude. Nat. Pet. N. 18, p. 26, July 28, 1926. Describes use of heat in breaking down emulsions. Clayton, William, Theory of emulsions. P. Blakiston's Son & Co., 1928. A review of breaking down of emulsions by high-potential alternating current. Clowes, G. H. A., Physiological chemist in the Gratwick Research Laboratories, Buffalo, New York. Emulsion of dilute solution of CaCl 2 in olive oil produces emulsion with water as inner phase, whereas dilute solution of NaOH in olive oil produces emulsion with water as outer phase. Cottrell, F. F., Process for separating and collecting particles of one liquid suspended in another liquid. U. S. Patent No. .987,114, Mar. 21, 1911. Covers the process of high voltage alternating current dehydration of emulsified oil, with insertion of a wetted septum between electrodes to prevent short circuiting. Cottrell, F. G., and Speed, J. B., Separating arid collecting particles of one liquid sus- pended in another liquid. U. S. Patent No. 987,115, Mar. 21, 1911. Covers the process of high voltage alternating current dehydration of emulsified oil with stirring to avoid short circuiting the electrodes. Cottrell, F. G., and Speed, J. B., Apparatus for separating and collecting particles of one liquid suspended in another liquid. U. S. Patent No. 987,116, Mar. 21, 1911. Covers the apparatus used for dehydration of emulsified oil under process U. S. Patent No. 987,115. BIBLIOGRAPHY 31 Cottrell, F. G., and Wright, A. C, Separating and collecting particles of one liquid suspended in another liquid. U. S. Patent No. 987,117, Mar. 21, 1911. Covers the apparatus used for dehydration of emulsified oil in which one elec- trode is rotated in respect to the other, with resultant agitation to avoid short cir- cuiting the electrodes. Cuno, C. W., Providing chemical treatment for petroleum emulsion. Chem. & Met. Eng., vol. 35, p. 165, Mar. 1928. Describes manufacture of Tret-o-lite and includes information as to amount and cost of Tret-o-lite in dehydrating oil. Curran, W. P., West Texas cut oils yield to scientific chemical treatment. Oil and Gas Jour., vol. 29, p. 76. Apr. 2, 1931. Use of Tret-o-lite in oil well. Dodd, H. V., Resolution of petroleum emulsions. Inst. Pet. Tech. Jour., vol. 9, p. 112, April, 1923. Discusses the problem of oil well emulsions. Dow, D. B., Oil field emulsions. U. S. Bureau of Mines Bull. 250 (1926). Discusses chemical and electrical methods of treating oil field emulsions. Dow, D. B., and Reistle, C. E., Physical chemistry of oil field emulsions. U. S. Bureau of Mines, R. I. 2692, June, 1925. A theoretical discussion of petroleum emulsions. Eddy, H. C, History of electrical dehydration. The Electrical Dehydrator, p. 1, Jan. 1931; p. 1, Apr., 1931. Reviews the Cottrell process and modifications. Eddy, H. C, Adjustable field dehydrator. U. S. Patent No. 1,430,295, Sept. 26, 1922. Movable electrode gives variable field strength to guard against electrical break- down. Eddy, H. C, Double field dehydrator. IT. S. Patent. No. 1,430,296, Sept. 26, 1922. Describes a series of rotating horizontal discs about a vertical axial electrode with stationary disc electrodes attached to wall of tanks projecting between movable discs in a double field. Rotating electrodes are used to minimize electrical break- down. Eddy, H. C, Variable field dehydrator. U. S. Patent No. 1,442,608, Jan. 16, 1923. A variable electrode spacing is used to lessen tendency to electrical break-down. Eddy, H. C, Rotating electrode closed treater for petroleum emulsions. U. S. Patent No. 1,466,208, Aug. 28, 1923. A closed tank with rotating electrode is used to avoid electrical break-down. Eddy, H. C, Process of dehydrating oil. U. S. Patent No. 1,580,591, Apr. 13, 1926. An electrical process to remove water and solid impurities from an oil emul- sion. Eddy, H. C, Method of and apparatus for dehydrating petroleum oil. U. S. Patent No. 1,779,695, Oct. 28, 1930. An electrical dehydrator in which treated oil may be introduced into emulsified oil. Eddy, H. C, Dehydrating apparatus having preliminary agglomerator. U. S. Patent No. 1,796,750, "Mar. 17, 1931. Mechanical agglomeration of dispersed particles previous to electrical dehy- dration. Eddy, H. C, Insulator, V. S. Patent No. 1,807,781, June 2, 1931. An insulator for bringing current into a dehydrator through a conducting metal lie wall. Eddy, H. C, Filtration process for breaking emulsions. U. S. Patent No. 1,807,833, June 2, 1931. The combination of a powdered dehydrating agenl and ;i porous diaphragm. Eddy, H. C, Method of removing a salt from oil. U. S. Patent No. 1,825,309, Sept. 29, 1931. Addition of solvent to dissolve salt with subsequent electrical dehydration. 32 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYINC Oil. Eddy, H. C, Method of salvaging oil from sludge. U. S. Patent No. 1,826,276, Oct. 6, 1931. Retreatment of sludge by secondary electric debvdration. Eddy, H. C, Treater for intermittent treating fluid. U. S. Patent No. 1,838,375, Dec. 29, 1931. A treater so arranged that the emulsion may be introduced between the elec- trodes intermittently to prevent electrical break-down. Eddy, H. C, Treater having centrifugal dry oil circulation. U. S. Patent No. 1,838,376, Dec. 29, 1931. The electrical path between electrodes is lengthened by di-electric baffles. Agi- tation by centrifugal flow of emulsion also lessens tendency for electrical break-down. Eddy, H. C, Apparatus for dehydrating petroleum oil. U. S. Patent No. 1,838,909, December 29, 1931. Emulsion is washed previous to electric dehydration. Eddy, H. C, Method of and apparatus for dehydrating petroleum oil. U. S. Patent No. 1,838,910, Dec. 29, 1931. Mechanical means for moving live electrode in tank to prevent electrical break- down. Eddy, H. C, Dehydrator having two live electrodes. U. S. Patent No. 1,838,911, Dec. 29, 1931. Means for moving concentric diverging electrodes to prevent electrical break- down. Eddy, H. C, Compound field dehydrator. U. S. Patent No. 1,838,912, Sept. 29, 1931. A primary and secondary field dehydrator with a reciprocating rod to vary the intensity of the fields to prevent electrical break-down. Eddy, H. C, Dehydrator. U. S. Patent No. 1,838,913, Dec. 29, 1931. A movable electrode to avoid electrical break-down. Eddy, H. C, Intermittent treater. U. S. Patent No. 1,838,91+, Dec. 29, 1931. A treater in which a nozzle through which the emulsion is sprayed forms one electrode and a cylinder the other. Eddy, H. C, Single electrode treater. U. S. Patent No. 1,838,915, December 29, 1931. The sprayed emulsion forms one electrode and a metal plate the other. Eddy, H. C, Combined washer and dehydrator. U. S. Patent No. 1,838,916, Dec. 29, 1931. Washing of emulsion with subsequent electrical treatment. Eddy, H. C, Method of and apparatus for treating oil under vacuum. U. S. Patent No. 1,847,602, March 1, 1932. Combination of vacuum and electric current dehydration. Eddy, H. C, and Hanson, G. B., Method of dehydrating petroleum emulsions. U. S. Patent No. 1,602,190, Oct. 5, 1926. Introduction into a pumping oil well of a gas which acts as a dehydrating agent. Eddy, H. C. and Worthington, J. T, Dehydrator. U. S. Patent No. 1,4-30,294, Sept. 26, 1922. Cylindrical electrode concentric to tank imparts a whirling motion to emulsion to prevent electrical break-down. Eddy, H. C, and Worthington, J. T., Double field dehydrator. U. S. Patent No. 1,838,- 917, Dec. 29, 1931. A jet of emulsion is passed through a sieve electrode to a rod electrode of opposite charge. Eddy, W. G., and Eddy, H. C, Discussion of electrical dehydration of crude oil. Jour. Ind. and Eng. Chem., vol. 13, No. 11, p. 1016, Nov., 1921. Describes the results of electrical demulsification by the Cottrell process. Eddy, W. O., Electrical dehydrator. U. S. Patent No. 1,440,774, Jan. 2, 1923. Use of rotating electrode to lessen tendency of electrical breakdown. Eddy, W. O., Dehydrator, U. S. Patent No. 1,440,775, Jan. 2, 1923. Movable grounded electrode about live electrode to decrease electrical break- down. BIBLIOGRAPHY 33 Eddy, W. O., Dehydrator having rotatable electrode. U. S. Patent No. 1,674,242, June 19, 1928. An electrical dehydrator having electrode which may be rotated by a jet of emulsified oil to prevent electrical breakdown. Eddy, W. O., Dehydrator having various intermittent voltages. U. S. Patent No. 1,838,- 374, Dec. 29, 1931. A dehydrator in which the primary winding of the transformer may be tapped at various points intermittently to give various voltages thereby preventing elec- trical breakdown. Eddy, W. O., Rotating disc dehydrator. U. S. Patent No. 1,838,918, Dec. 29, 1931. A grounded electrode which revolves in respect to a live electrode in order to lessen electrical breakdown. Eddy, W. O., Dehydrator having rotatable emulsion distributor. U. S. Patent No. 1,838,- 919, Dec. 29, 1931. The inner electrode is rotated in order to prevent a short circuit. Eddy, W. O., Electrical dehydrator having blade electrode. U. S. Patent No. 1,838,920, Dec. 29, 1931. Agitation of emulsion between blade electrode and tank electrode to prevent electrical short circuit. Fornes, C. W., Treat cut oils by single chemical method in Smackover, Arkansas field. Oil and Gas Jour. vol. 29, p. 76, April 2, 1931. Use of Tret-o-Iite inside the oil well. Fisher, H. F., General characteristics of California emulsions as viewed under the microscope. Trans. A. I. M. E., Petroleum Division, p. 359, 1931. The technique is given for preparation of microscopic slides. California emul- sions carry a negative charge. Fisher, H. F., Method of inverting the phase of emulsions. U. S. Patent No. 1,838,379, Dec. 29, 1931. Combined action of chemical to invert phase and electrical dehydration. Fisher, H. F., Dehydrator. U. S. Patent No. 1,838,921, Dec. 29, 1931. Addition of coarse water particles to emulsion to be treated subsequently by electric dehydration. Fisher, H. F., Method of dehydrating petroleum emulsions. U. S. Patent No. 1,838,922, Dec. 29, 1931. Series of live electrodes interspersed between grounded electrodes. Fisher, H. F., Dehydrator having hygroscopic emulsion inlet. U. S. Patent No. 1,838,923, Dec. 29, 1931. Elimination of emulsified water so that dry oil passes through the auxiliary field. Fisher, H. F., Dehydrator with high field intensity grounded electrode 1 . U. S. Patent No. 1,838,924, Dec. 29, 1931. Use of dielectric barrier to increase length of electric current path between electrodes in order to prevent short circuit. Fisher, H. F., Dehydrator having means for providing internal dry oil circulation. U. S. Patent No. 1,838,925, Dec. 29, 1931. Another form of dielectric barrier to increase length of electric current path and thereby prevent electric breakdown. Fisher, H. F., Electrical treater. U. S. Patent No. 1,838,926, Dec. 29, 1931. A shroud surrounding the outer electrode at same potential as electrode to direct the path of current flow, thereby preventing electrical breakdown. Fisher, H. F., Stepped cone type treater. U. S. Patent No. 1,838,927, Dec. 29, 1931. A cone electrode with series of troughs and crests fur [nit pose <>1 turbulent How to lessen short circuiting. Fisher, H. F., Dehydrator with means for directing emulsion through a high intensit) field. U. S. Patent No. 1,838,928, Dec. 29, 1931. Directs emulsion first to high potential portion of field. 34 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYING OIL Fisher, H. F., Elongated high velocity type treater. U. S. Patent No. 1,838,929, Dec. 29, 1931. Use of dielectric barrier to increase length of path between electrodes in an elongated high velocity treater to prevent electrical breakdown. Fisher, H. F., Apparatus for converting commercial frequency into high frequency cir- cuits. U. S. Patent No. 1,838,931, December 29, 1931. A mechanical rotor for increasing frequency. Fisher, H. F., Electrical treater having elongated circulation path and edge effect. U. S. Patent No. 1,838,932, December 29, 1931. A means to control flow of emulsion through electric field and thereby prevent electrical breakdown. Fisher, H. F., Electrical treater having elongated oil circulating path. U. S. Patent No. 1,838,934, December 29, 1931. Use of dielectric barrier to increase length of electric current path between electrodes to prevent electrical breakdown. Fisher, H. F., Method of dehydrating emulsion. U. S. Patent No. 1,864,721, June 28, 1932. Means for periodically increasing potential of treating field in order to prevent electrical breakdown. Fisher, H. F., Synchronous gap potential control for treaters. U. S. Patent No. 1,846,722, June 28, 1932. Means for periodically reducing potential of field to prevent electrical break- down. Fisher, H. F., Treater using high tension reactance. U. S. Patent No. 1,864,723, June 28, 1932. Change of wave form as potential between electrode decreases. Fisher, H. F., Gassaway, S. G., and Van Loenen, W. F., Electric treater having variable rate of flow with constant conditions in working field. U. S. Patent No. 1,838,930, Dec. 29, 1931. A primary, secondary, and tertiary treating system to prevent electrical break- down. Fisher, H. F., and Woelflin, W., Electrical treater having dry oil barrier supply. I'*. S. Patent No. 1,838,933, December 29, 1931. Use of dielectric fluid discharged by nozzle to maintain an envelope of dielectric about the electrodes to prevent electrical breakdown. Francis, C. K., Emulsified or cut petroleum. Jour. Ind. and Eng. Chem. vol. 8, p. 682, Aug., 1916. Description of emulsion containing water, sodium and calcium salts, solid mat- ter, and gas. Gassaway, S. G., Emulsion treater. U. S. Patent No. 1,838,822, December 29, 1931. Insulating baffle for guiding emulsion between electrodes so that substantially all treatment takes place between such bafflle and one of the electrodes in order to prevent electrical breakdown. Girwin, C. W., Dehydrator having high resistance wall. U. S. Patent No. 1,838,937, December 29, 1931. An electric treater with a coating of high resistance conducting material applied directly to the surface of the central electrode to prevent electrical breakdown. Girwin, C. W., Method of and apparatus for treating emulsion with alternating current. U. S. Patent No. 1,838,938, December 29, 1931. Change of electrode spacing in time phase with current alternation to maintain full positive and negative potential values. Hardison, S. J., The dehydrating plant of the Nevada Petroleum Company. Trans. A. I. M. E., vol. 51, p. 627, 1915. An attempt to heat emulsified oil at such a temperature as to explode the glo- bules of water emulsion. Harris, F. W., Dehydrator for petroleum emulsions. U. S. Patent No. 1,405,117, Jan. 31, 1922. Body of liquid is repeatedly circulated through electric field to prevent electrical breakdown. BIBLIOGRAPHY 35 Harris, F. W., Apparatus for removing water from petroleum emulsions. U. S. Patent No. 1,405,118, Jan. 21, 1922. Means for circulation of liquid to prevent electrical breakdown. Harris, F. W., Apparatus for dehydrating petroleum emulsions. U. S. Patent No. 1,405,- 119, Jan. 31, 1922. Method of heating crude oil during electrical dehydration. Harris, F. W., System of water control for electrical dehydrators. U. S. Patent No. 1,405,120, Jan. 31, 1922. An electrode in an emulsion above body of water which is in contact with oppo- site electrode. Harris, F. W., Dehydrator. U. S. Patent No. 1,405,121, Jan. 31, 1922. A closed dehydrating tank in which a body of water is constantly retained at the bottom. Harris, F. W., Method and apparatus for dehydrating petroleum emulsions. U. S. Patent No. 1,405,122, Jan. 31, 1922. A dehydrator in which the fluid is passed through a concentrated field at high speed to prevent electrical breakdown. Harris, F. W., Apparatus for dehydrating petroleum emulsions. U. S. Patent No. 1,405,- 123, Jan. 31, 1922. A dehydrator which includes a concentric chain electrode. Harris, F. W., Dehydrator for petroleum emulsion and water control for same. U. S. Patent No. 1,405,124, Jan. 31, 1922. Consists of a series of concentric cylindrical electrodes. Harris, F. W., Process for dehydrating emulsions. U. S. Patent No. 1,405,125, Jan. 31, 1922. Pass the emulsion through a body of water and then treat electrically. Harris, F. W., Process for dehydrating petroleum emulsions. U. S. Patent No. 1,405,126, Jan. 31, 1922. Pass emulsion through relatively dry emulsion and then treat electrically. Harris, F. W., Process for dehydrating emulsions. U. S. Patent No. 1,405,127, Jan. 31, 1922. Pass emulsion through dry oil, heat and treat electrically. Harris, F. W., Method and apparatus for dehydrating petroleum oils. U. S. Patent No. 1,405,128, Jan. 31, 1922. It is claimed that the electric current path may be desirably controlled by a superimposed magnetic field to prevent short circuiting. Harris, F. W., Process and apparatus for dehydrating petroleum emulsions. U. S. Patent No. 1,405,129, Jan. 31, 1922. The emulsion is forced under pressure through a confined space from which air is excluded and in which electric discharges are caused to take place. Harris, F. W., Method and apparatus for dehydrating emulsions. U. S. Patent No. 1,405,130, Jan. 31, 1922. A coarse emulsion is added in order to improve the electrical dehydration of a fine emulsion. Harris, F. W., Dehydrator. U. S. Patent No. 1,440,828, Jan. 2, 1923. Describes use of closed tank under pressure with automatic break of electric current with loss of pressure. Harris, F. W., Electric dehydrator. U. S. Patent No. 1,455,139, May 15, 1923. Oil between electrodes is agitated rapidly to prevent electrical breakdown. Harris, F. W., Apparatus for dehydrating petroleum oils. U. S. Patent No. 1,458,291, June 12, 1923. Superposed magnetic field to regulate path of electric flow of current to pre- vent electrical breakdown. Harris, F. W., Electric dehydrator. U. S. Patent No. 1,480,064, Jan. 8, 1924. Use of dielectric fluid between the electrodes to diminish tendency to electrical breakdown. 36 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYINO- Oil. Harris, F. W., Inlet bushing for electrical dehydrator. U. S. Patent No. 1,528,296, March 3, 1925. A mechanical design for electrode bushing. Harris, F. W., Process of preventing the persistence of chain formations in an electric hydrator for oil emulsions. U. S. Patent No. 1,581,205, April 20, 1926. Superimposing a magnetic field on an electrical field to prevent breakdown. Harris, F. W., Process of separating water from emulsions. U. S. Patent No. 1,609,546, Dec, 7, 1926. Addition of solid particles to an emulsified oil and then treating electrically. Harris, F. W., Electrical dehydrator with free moving electrode. U. S. Patent No. 1,838,- 828, Dec. 29, 1931. An annular screen electrode which may be rotated by flow of emulsion to pre- vent electrical breakdown. Heithecker, R. E., Some methods of separating oil and water in West Texas Fields, and the disposal of oil-field brines in the Hendricks Oil Field, Texas. U. S. Bureau of Mines, R. I. 3173, May, 1932. Describes specific field methods of dehydration. Koetschoer, Rudolph, Emulsions — zertorung in der Erdolinderstrie, Kolloidchemische Technologie, p. 806, 1932. A review of various processes of electrical dehydration. Kuczynski, T., Breaking of crude oil emulsions by chemical means. Inst. Pet. Tech. J. 14, p. 149, June 1928. Describes reagents used to break down emulsions. Land, R. E., Electrical dehydrator. U. S. Patent No. 1,467,003, Sept. 4, 1923. Concentric electrodes with current terminal through side of tank. Lawrason, L., Method of and apparatus for mechanically re-establishing the dielectric field in dehydrators. U. S. Patent No. 1,838,847, Dec. 29, 1931. Subjecting emulsion to mechanical vibration during electrical dehydration. Lawrason, L., Method of and apparatus for dehydrating emulsions. U. S. Patent No. 1.838.848, Dec. 29, 1931. Rotation of agitator between electrodes driven by motion of emulsion flow to prevent electrical breakdown. Lawrason, L., Treater having rotatable live and grounded electrodes. U. S. Patent No. 1.838.849, Dec. 29, 1931. Rotation of both live and grounded electrodes to prevent electrical breakdown. Lawrason, L., Emulsion treater having central cylindrical live electrodes. U. S. Patent No. 1,838,850, Dec. 29, 1931. A baffle to force flow of emulsion past a live electrode to prevent electrical breakdown. Lowe, W. F., Efficient heaters for treating oil. Nat. Pet. N. 21, p. 57, April 16, 1930. Describes field equipment for heating oil. Mahone, F. D., The electrical dehydration of cut oil. Report before the petroleum tech- nologists' division of the A. I. M. E., Tulsa meeting, October (1923). Describes use of the Cottrell process. Matthews, R. R., and Crosby, P. A., Recovering petroleum from emulsions by chemical treatment. Jour. Ind. and Eng. Chem. vol. 13, p. 1015, Nov. 1921. Use of Tret-o-lite both solid and liquid. McCoy, A. W., Shidel, H. R., and Tracer, E. A., Investigations concerning oil-water emulsions. Am. Inst. Min. Bull. 152, p. 1513, Aug. 1919. Laboratory methods of producing artificial emulsions and study of such emul- sions. Meredith, W., Dehydrator. U. S. Patent No. 1,428,178, Sept. 5, 1922. Use of horizontal diaphragm to divide chamber into two compartments, one of which is adapted to discharge and the other contains relatively quiescent oil near the electrodes to lower the tendency to electric breakdown. Meredith, W., Automatic discharge means for dehydrator. U. S. Patent No. 1,429,363, Sept. 19, 1922. An adjustable pipe outlet to maintain full chamber without added pressure. BIBLIOGRAPHY 37 Meredith, W., Process of and apparatus for dehydrating emulsions by osmosis. U. S. Patent No. 1,440,835, Jan. 2, 1923. Use of porous diaphragm and direct current. Meredith, W., Dehydrator. U. S. Patent No. 1,452,207, April 17, 1923. Agitation by rotation of electrodes to prevent short circuiting. Meredith, W., Dehydrator. U. S. Patent No. 1,480,091, Jan. 8, 1924. Emulsion is forced upward in small jets through fine material. Mills, R. V., Treating emulsions without cost. Oil and Gas Jour., vol. 27, p. 45, April 25, 1929. Agitation methods of treating emulsions. Nutting, P. G., Formation of oil field emulsions presents an interesting problem. Oil and Gas Jour. vol. 28, p. 34, Jan. 2, 1930. Emulsions of oil and water alone are easily broken down. Addition of foreign constituents makes a tougher emulsion. Parsons, L. W., and Wilson, O. G, Some factors affecting the stability and inversion of oil-water emulsions. Jour. Ind. and Eng. Chem., vol. 13, p. 116, 1921. Refers to various chemical reagents which may be used to break down emul- sions. Quinby, H. R., Dehydrator for petroleum oils. U. S. Patent No. 1,382,234, June 21, 1921. A series of vertical electrodes in which one set is supported from an upper live bus bar and the alternate oppositely charged intervening electrodes are supported from the base of the tank. Roberts, C. H. M., A New Theory of Emulsions. Jour. Phys. Chem., vol. 36, p. 3087, 1932. Gives theories of emulsions previously proposed, general theory of interfacial films, and suggests a new theory which is an extension of the currently accepted ad- sorption film theory. Seibert, F. M., and Brady, J. D., Process of and apparatus for treating oil. U. S. Patent No. 1,290,369, Jan. 7, 1919. Covers the process for low voltage direct current dehydration of emulsified oil. Sherrick, J. L., Oil-field emulsions. Jour. Ind. and Eng. Chem., vol. 12, p. 133, Feb., 1920. Describes emulsion and common methods of breaking down emulsions. Sherrick, J. L., Emulsifying agents in oil-field emulsions. Jour. Ind. and Eng. Chem., vol. 13, p. 1010, Nov., 1921. A study of inversion of phase of emulsions. Smith, L. E., Used oil field boilers form part of dehydrating plant on lease. Nat. Pet. N. vol. 16, p. 89, June 18, 1924. Use of heat in breaking down emulsions. Tanner, J. O., Emulsions. Jour. Inst. Pet. Tech., vol. 11, p. 502, Oct., 1925. Discussion of emulsions. Thompson, A. B., Prevention of emulsions. Jour. Inst. Pet. Tech., vol. 10, p. 326, June, 1924. Various methods are discussed for the prevention of emulsions. Uren, L. C, Oil field emulsions. Nat. Pet. N. 21, p. 59, April 17, 1929, and p. 59, July 3, 1929. A discussion of petroleum emulsions. Van Houten, H. C, Oil treating. Nat. Pet. N. 21, Dec. 11, 1929. Talk before El Dorado Chapter of American Petroleum Institute. Van Loenen, W. F., Emulsion treater. U. S. Patent No. 1.S3S.889, Dec. 29, 1 93 I Rotation of primary and secondary electrodes to prevent electrical breakdown, Van Loenen, W. F., Electrical dehydrator. U. S. Patent No. 1,S3S,890, Dec. 29, 1931, Combination of nozzle spray, a chemical reagent, and electrical dehydration, Van Loenen, W. F., Treater with variable pressure. V. S. Patent No. 1,847,541, March 1, 1932. Combination of intermittent change of pressure and electric current dehydration. 38 ELECTRIC CONDENSER PROCESS FOR DEMULSIFYING OIL Wiggin, J. H., Evaporation losses from the dehydration of crude oils. Nat. Pet. N. ]3, p. 59, July 1, 1921. Discusses the lighter fractions of crude oil lost in dehydration. Wn.cox, E. H., New process in dehydration of crude oil. Oil and Gas Jour., vol. 28, p. 38, Jan. 2, 1930. Describes successful operation of electrical dehydration. Worthington, J. T., Treater having revolving electrode with wave shaped arm. U. S. . Patent No. 1,838,976, Dec. 29, 1931. Use of revolving electrode to give variant electrode spacing to avoid electrical breakdown. Worthington, J. T., Water level control device. U. S. Patent No. 1,762,538, June 10, 1930. A mechanical device for constant level control of water below oil based on their differential electrical resistivities. Worthington, J. T., Dehydrator having horizontal revolving electrodes. U. S. Patent No. 1,783,595, Dec. 2, 1930. A perforated horizontal electrode rotj^d to lessen tendency to electrical break- down. Worthington, J. T., Treater having combined electric field and washer. U. S. Patent No. 1,838,977, December 29, 1931. Means for introduction of fluid into emulsion to be treated electrically. Worthington, T. T., Combination concentrated field circulating treater. U. S. Patent No. 1,838,978, Dec. 29, 1931. Use of third electrode to give concentrated field. Worthington, J. T., Dehydrator having radial venturi-type electrodes. U. S. Patent No. 1,838,979, Dec. 29,' 1931. A combined nozzle and sleeve of venturi-type through which the emulsion is passed. Worthington, J. T., Dehydrator with centrifugal discharge electrodes. U. S. Patent No. 1,838,980, Dec. 29, 1931. Means for directing a fast moving stream of emulsion between electrodes to avoid electrical breakdown. Worthington, J. T., and Fisher, H. F., Pipe line treater. U. S. Patent No. 1,873,857, Aug. 23, 1932. Use of rod and sleeve electrode. Wyant, L. D., Electrical dehydration of oil in the Comodoro Kivadavia field, Argentine. Nat. Pet. N. 20, p. 119, Oct. 17, 1928. Describes use of Cottrell process. "WASCHER'S" UBRARY BINDERS S07 S. Goodwin Urbana, 111