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Tests and properties of crude petroleum emulsions

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Tests and properties of crude petroleum emulsions

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Content TESTS AND PROPERTIES OF CRUDE PETROLEUM EMULSIONS (L 3JT A Thesis Presented: to the Faculty of the Department of Chemist ry Dnirersity of Southern: California In Partial Fulfillment of the Requirements for the Degree S e - i e . v * c < g « , Master of Arts by Hugh L. Slay den June 1935 UMI Number: EP41474 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. O ' t S & i i l i f f i t o r t P u b ! s j h n g UMI EP41474 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 This thesis, written under the direction of the candidate’s Faculty Committee and approved by all its members, has been presented to and ac cepted by the Council on Graduate Study and Research in partial fulfillm ent of the require ments for the degree of Ma s t e r . . . ofScienAQ TABLE OF COHTEUTS CHAPTER PAGE I. IHTRODUCTIOF. .....*..**......... . * ......*..... X II- DISCUSSIOF . . . . *............... . . * * 5 General Discussion of Emulsions***.*.*......... 5 General Discussion of Crude Petroleum.*.. ****** 19 III* PETROLEUM EMDLSIOBS4 ADD TESTING. ..... 24 Crude Petroleum Emulsions.***.****.*.*.***«••** 24 Paraffin and Congealing-Ci 1 Problems......•.•** 27 Sampling for Testing*.**»**•**»••***••*••••••** 31 Free Water T e s t i n g * 31 Petroleum Emulsion Testing. 32 IT* DE-EMULSIFICATIOR. ... *....... 43 V. EMULSIFIED ASPHALT....... . 61 VI. LABORATORY EXPERIMENTS ADD TESTS. ...... 68 VII. COHCOTSIOKS........ ......... 80 BIBLIOGRAPHY...... 82 LIST 02? TABLES AND PLATES TABLE PAGE I* Properties of Oil and Water Used in Etaulsion Formation* 63 II* Methods of Formation and Stability of Crude Petroleum Enulsiona. 70 III* Viscosity and Surface Tension Varying with the Clearance of the Colloid Mill.*..... ........ * 72 IV. Percentage of Water and Its Effect on Viscosity and Surface T e n s i o n . 73 PLATE 1 - 4 Photomiorographic* Plates of Emulsions 76 CTAPnra i mmmmzmm; A Statement of the Problem. it is difficult te name a more? valuable natural resource than petroleum* lie usee in industry and arts of peace are now a necessity* The country without a constant source of supply of petroleum during* a war would be under the greatest of handicaps* Con sumption ha® mounted year after: year as its use has spread into new field®* Petroleum supplies was One of the bone® of contention that led to the World War*, and no email amount of bargaining!, diplomacy „ and ere® trickery wa® done in gaining advantage in the distribution of the Inserts petro leum resources* The importance of petroleum make® it necessary to * 4 know the composition physically and chemically of crude petroleum: wherever found* In payment of lease® and royal ties there must be an accurate method of determining the purity of the produced oil* fee production: engineer and the refiner must know the composition and characteristic® of the oil before they can plan efficient method® of transportation* storing and refining* There ha® been a great deal of laboratory and field work done in the study and treatment ef\ crude petroleum 1 2 emulsions*. A great deal has Men written oh the subject* The writer of this paper, in studying the literature, found it to he weli divided into two classes, namely: that which would he of interest to the chemis t * and that which would he of interest to the engineer*. Much of the literature was written for or ty petroleum production and transportation engineers*. An equal amount covered the chemical treatment of petroleum emulsiohs as laboratory problems. The writer, familiar with mariy engineering problems, became of the opinion that a paper on laboratory tests and treatment of crude petroleum with considerable discussion and explanation of the chemical phenomena would serve to enlighten the engineer, as weli as present the problem to the chemist in its broadest aspect* The writer thought it well to consider the problem as one of formation as well as composition and separation. Several samples of crude petroleum’ were secured f rom various fields for study. One sample which had previously been separated was chosen for re •emu! si f f eat i on. The properties- of crude emulsions are the same as found in other liquids* hence, nm new tests need be develop ed. A testing procedure capable of giving quick, accurate and comprehensive results is worthy of developments i eH£rasB ii m s m s B i m General Discussion of Emulsions* Dilute Emulsions and Emulsifying Agents* Mn emulsion is a system of two? liquids not soluble in each other, but of which, one liquid is dispersed, in the second in small droplets as the dispersed phases the second liquid is the dispersing phase* In most all casesp the system may have one liquid in the: disperse phase under certain conditions’ , and the same liquid in the dispersing phase under other conditions* Emulsions are of two general classes—-dilute simple solutions of oil in water, and more complex emulsions of oil In water and water in all* This last class of emulsions contains another substancet namely * an emuls ifying agent which gives it stability and permanence* The Importance of the. dasslfication is that the dilute emulsions’ may be studied as colloidal suspensions:, and the complex emulsions offer excellent material for the study of surface and inter- facial tension and the structure of interfaces* Win. Clayton , ^Theory of Emulsions*. 3 Parer oil and water when shaken together will emulsify* hat will separate into layers a a - soon an quiet* If a email amount of oil* up to two per sent* he boiled with water under a reflux condenser* an oil^in-water emulsion will be formed* If a small amount of pure Water is boiled with pure oil under the same cond.itions^ they will separate on standing* At tempts to form water-in-oll solutions hare only been possible when there has been doubt as t o : the purity of the materials* && far there is only one type of emulsion for two pure liquids* It is the ati-im*water emulsion in which the dis** parsed oil will be less than two per Sent* The size Of the dispersed oil droplet® is in the Order of ICE^cm* while the size of particles in a eel laid is The sizes of these emulsions hate been conclusively determined by Homan* lewis and others* It is theoretically possible to have an emulsion con taining 7A& of the dispersed phase in 26$ of the dispersing phase and have all droplets true spheres* This concentration may be increased by packing the droplets together so? as to distort them* Mauls ions hare been made c ontaining 99$ of the dispersed phase in 2$ of the dispersing phase. Fiekerlng:, who first did this work*, obtained stable emulsions* Gfoncent rated emulsions are only stable when a third substanee is present* This- third substance forms ah adsorbed The ©dl globules fk ait ail-in*wafer einuTeioh are nega tively charged* fhe origin of the charge is still open to question* fhe electrical charge is: believed to he due to the adsorption of ions* An equivalent amount of Opposite charged electrons arrange themselves about the globules and its: ad sorbed ions#, This theory is known as the "Helmholtz double layer theory** There i s : much controversy over* the existence and properties of a "double layer** Its discussion enters into potential difference4 Investigafions Of Variations in the cataphorefie mobilities of oil droplets in water have shown that the mo bility of negatively charged droplets: increases with the di ameter of the droplets for the range from 0* 000b to 0.04 nzs. The double layer is the criteria for predicting this rela* tionship between size and mobili^* The mobility approaches asymptotically an upper limits If is assumed to approach a lower limit also* but it is hard to conclusively Judge from curves thus far obtained* Brown dissevered by use of the ultramicrossope that in emulsoidff* euspensOdds* and colicids of metals:* hydros ides and sulphides the dispersed particles have a random zigzag mot ion* This has: been explained as due to the bam** bardment of molecules in the dispersing phase on the parti cles* This motion: is noticed on particles whose diameters are below ' $ ■ fee and the speed of the motion increases with a decrease in size* The stability of emulsions depends o i l the presence of" am. emulsifying agent and the adsorbed film at the eiX-wsfcf boundary* The stability ie influenced By: fl/| the interfacial tension tending; to coalesce the droplets | (2) the electric charge on the droplets which forces them apart? and (Z} the Brownian morement which also tends.- to keep the droplets apart* In low concentration Of electrolytes the anion is more strongly adsorbed, but as the eoneentration is increased the cations ate mere and more strongly adsorbed* Slayton says that most of the work on stability of emulsions relates to the influence of added electrolytes. Stability is the least when the particles are nearly neutralised; and the po>* tent ial difference between the particles and the medium is zero* * Bp to 1910 all emulsions were thought to be eil-in- water systems* Gstwald showed the existence of two types , namely? cfX-in*wate:r and water—in-oil* The type of emul sion formed is dependent on the emulsifying agent* Water soluble colloidal substances promote emulsions of oil dis persed in watery oil soluble colloids promote water disperse# in oil* Gelatin, as an emulsifying agent, acts with oils of both glyceride and hydrocarbon character to form aiX-in-water emulsions* Eharmaeenfieal emulsions are prepared by use of egg yolk* saponin* gum; acacia* ease in * lecithin* agar and starch* and in faet nearly any pulYerized protein may Be used. Alkalies indirectly act a a emulsifying agents in that they act with fatty acids to form soap which is an excellent emol-* sifying agents Wate£~t&M^ii emulsifying agents are such substances as crude ruBBer* paraffin* rosin*, sulfur* gun cotton* oleates of Hg* M* Chr* or Zir* Many finely divided materials etaBilize emulsions* This list includes argillaceous starch* the Basie sulfates of Fe* ©W* Fi* Zh* and AX* calcium eerBenate* cal cium arsenate* and most any fine clay* To oBtain emulsions of oil in water the agent must Be more readily wetted By water than By oil* Ferric oxide promotes emulsions; of oil in wafer* while earBeir Blank promotes water^in^sfX emulsions* t F s i t tg: crarBon Black as the agent*. Koorc found that the larger the amount a carBon used* the smaller the water gloBules* and By keeping the amount of oil const ant the diameter of the gloBules Increased with the total amount of Both liquids* Emulsifying agents will act to: nullify the powers of other agents* Carbon Black is antagonistic to all tea * and mercuric iodide is antagonistic to silica* Alumina intro duced into an emulsion stabilized By earBonS will Break the emulsion* There is no known elassif ication of agents arranged in their stabilizing order* If is known that certain suB- stances: hare: certain properties*. In one experiment in making: olive ©il-ihr-water emulsions* It wan found that the agent© had' the following orders- alhumose % blood serum* egg; albumin* acid albumin* and alkali albumin* The agent may have effect on the size of globules formed as gum arable forma emulsions with oil globules small er than when gum tragacanth is used* In another, experiment for dispersing benzene and kero sene the. order was as foliowss egg alhumin, starch, gum> arabic*, dextrin and sn&ross* Piekering graded soft soap as the most effective agent for oil—1 n^water solutions. Sodium sterafe or sodium patmdfste are also good agent&* The cal cium salts may also he used* The agents for water—in^oil emulsions may he roughly graded" as fellows* haste sulfa tear of copper* hiekei* andt alumlntar* lime* silica* ptasfei* of Badris and fine powders* The points to he considered in grading agents are the wetting of the solid by each liquid* the size of particles* and the amounts required under standard conditions* The modern view of emulsions* considered from the langmuir-Harkins theory of orientation* is that oils and fats of animal or* vegetable nature should have similar emulsifying qualifies in: soap or water solutions* Mineral oils should he less readily emulsified as they do not contain carboxyl or have an affinity for Wafer* The study of oil-in-water emul- sions is of less importance than the study of the water-ih— oil type for the pappose of this paper*. Emulsions of oil-in-water wary ik color from white to pale yellow* Water-in-oil emulsions- fake the color of the oil but get limiter as the water cranteht is increased* ISmt!— eions may he t ranspafeni if the liquids haire the same index of refraction and optical properties* Chroma tie emulsions are made with materials of the same index of refraction hut different option! properties* The Tiseosity of emulsions is known to increase greatly with concentration of the dispersed phase* fee emul sifying agent often affects the tfseosity of the emulsion as the concent ration of the dispersed agent may he increased!* Adsorption Film at liquid — liquid Interface* By properly choosing the emulsifying agent, an oil-in-water or water—in-eil emulsion may he made* SUeh emulsions may hare their phases reversed by choosing suitable reagents* Any general theory of emulsions and their agents is capable of including and' explaining the above facts * Bancroft, in ac cepting the work of Bonnan on surface tension with its limi tations^ was able to form a clear theory of emulsions* Bonnan considered only oil-in-water emulsions and considered the film around the oil globules: to he part of the water phase* Bancroft drew a distinction between the two types of emul sions and shewed that there are: three phases in concent rated in oil-wster solutions. The two. liquids are separated by a film, and both liquids wet it. The type of emulsion promoted is dependent upon the re 1 at Ire magnitude of the surface tension on each aide of the film. If there is a difference in surface tension, which there practically always is- , there will he a bending of the film cdheavely towards the side with the higher surface tension. The nature of the emulsifying agent controls the type of emulsion to be formed, namely* an emulsion of oil in water is farmed if the agent is more readily wet by water; conversely, a water-in-oil emulsion is formed if the agent is more readily wet by oil. Bancroft has shown that a substance, to act as an emulsifying agent, must be adsorbed, into the surface separat ing the two liquids and form a coherent film. If it were not thus adsorbed into the dineric interface, it would be unable to form a film enveloping globules of one o f * the liquids. Bancroft also said, *When shaXen with water and a non-misci- ble organic liquid, solid particles tend to - go into the water phase if they adsorb water to the practical exclusion of the other liquid? they tend to go into the other liquid phase if they adsorb the organic liquid to the practical exclusion of the watery and they tend to pass into the dineric interface in case they adsorb the two liquids simultaneously*. Since Bancroft made this statement, many men have put it to test. Soaps of monovalent cations, which are not solu- 11 hie in oil, readily pass into the water phase, thereby for®* ing a f ilm mere easily wet by water than by oil; on which the surface tension on the water side will be lower than on the oil aide* Thus, the film will bend concaTely towards the eil and will surround it as a sphere*. Shape of di- or trivalent cations freely pass into oil, and form an oil adsorbed film Which bender and forms water spheres* When opposing emulsify- ihg agents are present in such quantities* that their effects are balanced , the oil and water phases will separate af ter agitation* Increasing the concentration: of sodium hydroxide in oil means a greater lowering of interfacial tension and greater dispersion: of ail; since the relative permeability of the system to water is increased* When the concentration reaches the point when no more alkali is adsorbed to the oil, the maximum1 permeability of water is reached,and an oil-in- water emulsion will readily form* If a calcium salt is then added to the emulsion, the permeability to water is decreased, and the system becomes permeable to oil*- There is then a reversal of phases, and a water-in-oil emulsion is: formed*. Much work has been done in discovery Of antagonist ie emulsifying agents. At times both agents will dissolve when added to the water phase* This is explained by certain bio logical permeability phenomena* Some of the agents: hare been: classed as destructive, and others as protective1 agents, de- pending on the desirability of forming, maintaining, or The Physical Qualities of Bmulstous* Emulsions lend themselves: to laboratory examination in: all qualities:* BHblstone are easily separated far a study of their parts* The study of emulsions includes determination of surface and inferfaciaX tensions* the nature- of the internal or external ! * the concent Eat ion of the phases in the eim&sion* the of diversion, and viscosity* Surface and interfacial tension determinations are im* portant in all colloidal chemistry* There ate numerous accu rate methods simple in technique* There are, in general, two methods* disturbed surfaces and undisturbed surfaces* corre sponding to such methods as the ripple method* and to these similar to the capillary tube determinations* The du irony Tensiamefer is based? on the principle of forcing a metal ring out of the surface of a liquid* A plat 1 num-iridiurn ring of 4 cm* is made of wire of diameter mm* This* is suspended on an arm rigidly fixed to a fine steel piano wire* secured at both ends in torsion heads* each of which is driven by a worm gear arrangement* The liquid is placed in a fray and the ring wetted in the liquid* The arm connecting the piano wire and the suspended loop is kept at zero balance until the rupture takes place* The reading is taken from the dial at one end of the piano wire* A knife 13 edge has been substituted far the ring in some cases and has found fairer with certain emulsions* The capillary rise method gives the static surface tension* Great care must he exercised in cleanliness: of appa ratus* temperature control* and tuhe calibration* The theory of the capillary tuhe is that the surface tension of a liquid in a capillary tuhe is equal to one—half of the tubes diameter multiplied by the height of raise in the tuhe* multiplied by gravity* and the difference in density of liquid and vapor phases, a m i rhg- (d — d*) * A simple method is to force the liquid into a capil lary tuhe and determine the force required* The drop weight method has received considerable at tention in the past fewr years and is exceedingly accurate* The theory of this method is that the weight of a drop of a liquid slowly detached from a vertical cylindrical tuhe is proportional to the radius of the tip of the tube* The weight of the drop in equilibrium then can he defined in terms of size of tuhe and surface tension* This has not been uni versally accepted as it appears that the shape of the drop is dependent on its weight* Certain corrections that must he made are furnished with the instrument* The speed of for mation: of the drop is also a factor* The mass of one drop is determined and its weight calculated with the density* The interfacial determinations are made by somewhat similar methods- The ring ef the tehslometer is attached t© a rigid: support maintained perpen dieulsr- A hrife edge frame may also " f e e used- The capillary method is determined "by emersing the capillary tuhe i® one liquid* A second liquid is poured lu- The tuhe- is Raised until the Interface mlaene falls t® a 'definite paint- A fine platinum wire’ is adjusted t© touch the interface- The distance between the mi ecus and the inter- face is then measured- fhe same: formula is used as was used for determination of surface tension- fhe drop weight method is one of forming the drops of one liciuid in the ether by releasing from a . bent tube- It is often desirable to determine which phase is the dispersed and which the continuous phase- Three methods hare been used in this determination- The first method is that of adding a dye soluble in hut one phase- If it is soluble in the continuous phase , the color will spread throughout the emulsion- If* however* the dye is soluble In the dispersed phase* if will only color those few globules that it comes in contact with- This method is correenient in dealing with solid emulsions- The second method is that of dilution- The continuous phase can he readily diluted hut not the dispersed phase- The electrical cohducfance method is the third mefhod- €?i!-In-water emulsions , especially if the water contains an electrolyte * will conduct electricity* but the water^in-oil solutions do net* This method is tossy accurate and is ex*- ceed'ingly good for determining the reversal point of oil*- water emulsions* The eoneentxation of ah emulsion may he determined by breaking' the emulsion and separating: the liquids#. For dilate eolations, the turbidity may he compared to standard emulsions* The method is based on the Tyndall effect* The inst ruments are known as nephe lome ters * t urhidimeters, and tyndallmetera. The measurement taken is that of the brightness of a light through a given depth of emulsion viewed at right angles to the beam of light* Two columns of lieprid are viewed * — one a standard, the other unknown* Bright metal plates- are so ad justed to? make the columns appear t o . have the same brightness* The size of globules? is receiving: increased interest of late* The size of droplets has been associated with the speed and the frequency of settling* The uXtfcamieroscrope bass been used to observe the speed of separation* All determi- net ions of this method are made on partially stable emulsions* ^ntfLaifleation* As we have seen* emulsions- are two or three phase systems, in which one phase is dispersed in small globules in the: other* Th# technique of emulsification is important industrially and in the laboratory * Commercially * emulsions are made in double walled tanks,, t o . allow for temperature control* by means of mechanical stirrers,, pro— pellere* repairing baffle plates* warm earew®r or injectors* Usually emulsions* are made in tanks: to batches* tot continu- ons:—flow methods are gaining farofv lemperature? rise lowers the wieaosity and aide in toe movement of the liquids* It also toe an effect on the inters facial tension and the atoarption: at the interface* M temper* ature rise lower® the interfacial tension of ron^mieeible liquids j hence* emuheifioation to made easier* toere are case® With partially miscihle liquids where the Interfaeial tension rises with a rise in temperature* tm such a case, it is necessary to control the temperature* In cases where the emulsifying agent is soluble to tot one phase* a temperature change may he dtoadraniageaus * Each emulsion provides a different problem* Agitation to necessary in all eases for emnlsification* However* in certain cases violent agitation will, break an. emulsion* In certain cases* t h e * . size Of the droplets are to~ creased with agitation*. Water-fn*od” l emulsions fend towards greater dispersion when agitated* toe time of agitation is a factor as well as the violence* I n* many cases*; intermittent shakii^ over a long period is more effect ivey than violent agitation over a short period* toe rest interval between shaking is a factor with some emula.ions* toe f ault of the shaking method of emuleif leaf ion is that there is not an increased: tendency for the globules to break up#, Shaking does net produce uniform globules* Clayton? has pointed, out the numerous Ways? in which emrlsione haTe heen formed., He asks: that some uniform method he established that measurements: and data obtained may hare more aomparative walne#. Clayton gires ues *a safe working guide* in the light of present experience* is to add slowly the phase to he dispersed to? the other phase fcontaining: emulsifier^ in bulk* stirring continuously#, Hhraekell*s: apparatus: might serre as: a aonYenient standard: agitator#, At the same time * there is abundant eYidence that technical emulsions of any concentration may he prepared by the use of colloid mills* the emulsions e^ribitihg remarkable stability % all of which: emphasises the need of a thorough inrestigation into the mechanical or preparatory aspect: of emulsions*. As said abowe * emulsions that hawe bOeir formed by shaking: or agitation seldom: contain globules of uniform size. It is essential for laboratory work and many times for in dustrial wa&m that emulsions be homogeneous#. The emulsions must often be treated to get uniform aimed globules* and the process of such treatment is: termed" homogen izationv The laboratory^ is now experimenting with homogenized emulsions^ it is expected that they be: more and more in demand in ^ Winv Clayton,. “Theory of l&iulsions** ® Bideal* ^Surface Chemistry*# industry* The. milk industry using h<magei)tlz£& emulsions in studying many of its problems* Homogenizsiion may " f e e per formed! under controlled temperature? and pressure ranges* Ifethods: of homogeniza.fi on embrace a fukhing effect* Home methods then force the emulsion through small, holes or a rest ricted opening* Holloid mills are of Tario.ua; designs* hut the: type most used is a hydraulic disintegrator* The rotor consists of a smooth face Upon the frost rum; of a cone working in accu rate and. close? relation to a similar ground surface of a stator* A f ine clearance of 0*002 in* upwards is maintained* 'A centrifugal pump effsdf; is created* and the mixture is drawn through in an ewen continuous stream* The speed varies between 1*000 and 20 *000. revolutions per minute* Por the instrument with a IS in* rotor can handle between 1*000 and 1*500 gallons per hour* A mare recent type of mill uses studs an the rat or and stator* Ext remely fine and stable emulsions may he: made with, this machine* Be-Emol a if le af i on* Pe-emulsif ication or the breaking of an: emulsion is often mare important than the formation of an emulsion* Emulsions are found’ in many industrial processes that must he broken or kept from forming* In general, there are three methods of breaking emul sions, namely: chemical* physical and electrical* The theory of chemical de-emtrlsi f i cation is to introduce a soluble agent into the dispersed phase to counteract the agent in the e:on*~ tinudue phase# The pi^siesl method is one of increasing the fence: of gravity by centrifuging# The electrical process is one of passing a high TOltage alternating current through the emnisiisii* and breaking the film about the glehnlee# Since all of these methods are used in dehydrating petroleum, further discussion will, be found in the discussion of crude petroleum emulsions# General Discussion of Crude Betrcrleum Crude petfoleum nearly alwaysi contains most of the paraffin: series from &% to Uhsaturated hydrocarbons * together with small quantities of compounds containing oxygen* nitrogen* and sulphur*, are present in varying amounts depends ihg on the field and place in the field*. Oils from some localities contain considerable quantities of naphthalene,, anthracene, and asphaltunr# All ails contain foreign matter# As impurities* we find water and suspended solid sub stances# The solid substances consist of a small amount of day and fine sand* all of which settle out in time# The water may he merely associated With the oil in a free state* or it may be finely divided and? present in emulsified form# The free oil will separate by gravity settling* although in cases of extremely heavy oil* it is often helpful to heat the oil to lower its viscosity. later will settle from semi- permanent emulsions, hut those of a permanent type may stand far year® without sihowing; sighs of separation. Mc€£oy, Shidel and" Trager^ gave some data to the extent, that the; water eonv tent of permanent emaXsians was 66%+, The: stability of emul sions is due to their method of formation and the emulsifying agents The emulsions shown in Table IX, after months* of standing:, showed no settling., While it was- difficult to get emulsions of over 56% water to form in the colloid mill,, those of 1% water to* more than. 66$ that did' form were stable. As yet» there is ho direct proof of the conditions? of origin of petroleum. There are some seven or eight theories5 of petroXeum formation. Mendelejeff believed that the action of water on iron carbides formed acetylene, which later, by polymerization and rearrangement of molecules became petrole um. There were similar inorganic theories advanced, but evidence is lacking or unfounded!. Engles advanced a theory that petroXeum was originated from animal remains deposited on the ocean bottom, later to be covered, elevated and ^ Sf isCSOy, Shidel, and frager, Investigations concerning: oil-water emulsions„ Transcript, dm. Inst, of Mining and Met. Ehgrs., vol. 6?b, pp. 45€M*S, OampheXXft M. E., Historical review of theories ad vanced by American geologists to account for the origin and accxinasiation of oil, Been;. Gfeol., vol. b, Ho. d, pp. 365-88, (191X1, subjected to metamorphic action* Hofer advanced a theory of vegetable origin similar t o ; the formation of coal* The gener ally accepted theory of origin, based: oh a wide study of all. known oil fields, is a combination of the last two* Both animal and7 vegetable matter, deposited with other solid de- tritaX matter as marine deposits, f orm the entree reek* In the absence of oxygen* put rifactioh taken place with the liberation of nitrogen, Which, with the plant and animal fata, forme the petreXeuHE* The evidence to Substantiate this theory i s : that oil similar to petroleum may be distilled from marine deposits containing: diatoms* formahifera, seaweed and fish remains*. This, theory is easily accepted where there is s presence of sulfur and nitrogen in the oil, as both of these compounds are found in marine animal remains* There is only little hesitancy in accepting this theory for all but Pennsyl vania f ields appear to be marine deposits* Petroleum production is not confined to any one geo logical period* Hearly every period as old as the Cambrian has yielded oil in some part of the world* The Paleozoic Bra furnishes the axis of Pennsylvania * California finds her oil mainly in the Eocene* but also ih other Tertiary rocks* Buesia, likewise, produces oil from the Tertiary formations* £rude petroleum varies in color through shades of reddish brown to black* Tints of green, blue, and yellow may be found* The color, like other physical properties, varies with composition, emulsified! water, and; suspended solid matter* The gravity A-P.l* is lowered due to? the presence of water* The most noticed variable is the viscosityS* which in- creeses rapidly with the increase in water content* Many petroleum emulsions are too viscoo# to handle economically, unless dehydrated near the well* The recovered oil may he of excellent quality allhough the crude product was of little value* On distillation^, petroleum yields gases, liquids, and semisolids in the order named* The low hailing: fractions yield methane^ petroleum ether, gasoline, benzine and kerosene The middle hailing point fractions yield diesel oils, spray oils, and fuel oils* The high boiling paint fractions yield lubricating oils,: paraffin wax:, vaseline and aaphaltum* Fefnoleum is classed as either "paraffin—base * oils or "asphalt f c^base* oils depending on predominance of hydrocarbons of the paraffin series or Of the benzene series* The first yield a high percentage of residuum: wax, while the latter yield a high percentage of residuum asphalt* Pennsylvania, oils are •paraff in*4*ase*i California oils are "asphaltIe^base* Fort ex, C • f*, The Carbon Compounds, Gfinn & Co* , pp* 18-10, (192&I* *Faraffin«~base, r crude ail usually contains^ colloidal amorphous matter which only assumes* the crystalline state after diet i Hat ion* There is probably a physical effect of heat which changes the waaeline-lLike amorphous matter to crystalline wax* The residue of such oils, after gaselinei and kerosene fractions! hare been remered* will become quite solid* due to the set of the paraffin sol* The black or dark-coiared *asphaificMtaee* oils can~ tain bituminous matter.. The bituminous’ matter, which is colloidal asphaltic material, may readily be coagulated by means of strong sulfuric acid*. These colloids may also? be broken by centrifuging or by adding electrolytes* Crude oils are sols in which the disperse phases are solid gels,, such as asphalt, together with liquid particles* ® Dunstem, Br* A* B. B., Colloid Chemistry in Fetrole urn, Alexander Colloid: Chemistry,’ Tel** 3 , . p . . 491* CHAPTER III PETKQEEUM EMDLSXOUS: A3TO TESTIFY Crude Petroleum Emulsions In practically every oil field, crude petroleum comes to the surface in an emulsified condition* It may he free flowing: liquid or it may be a semi-solid’ * Some emulsions separate readily on standing,, while others are nearly impossi ble to break* They are usually the water—in-o il type of emulsion, although many are mixed* The most atabXe emulsions^ are those in which the water droplets’ are extremely fine* The smaller the dispersed globules, the greater is the force required to break the film surrounding the globule, so that it can coalesce. The sta bility of the' emulsion is also dependent on the agent which causes? the film formation* These emulsifying agents' are many, and most of them may be found in crude petroleum* A short list, includes! asphalt, resins, naphthenic acids, hydrocarbons of high molecular weight, and f inely divided solid' substance, such as clay* * Morrell and Engl off, Colloid Chem. of Petroleum, Alexander Colloid Chem., vol., 3, p. 503. 24 I t- iS' possible» . in certain cases:, to produce oil with out emulsion formation^* These cases are tare, but show that ail oil in the ground is not emulsified*. Some oils have little waters On examination, it is found that the oils of Fbnnsy I van i a, West Virginia, South eastern Ohio i and Eastern Kentucky are nearly free from emulsified water* Those oils of greater asphalt content form more stable emulsions* Heavier oils form more stable emulsions than do lighter oils of the same district*. Oils from the Gulf and Hid—Continent fields are nearly ail emulsified* California crudes, especially the heavier oils, contain both free and emulsified water*. Emulsions may he& formed® in the sand as the oil migrates toward the hole, or it may be formed by agitation of the pump or other recovery devices*. It may be formed as: the oil is forced by pressure through any of the thousand's of small and large openings, from the time it starts flowing towards the well, until?' it is in the storage tank:* The water present may be top water, bottom water, or edge water*. There is ho. evi dence that the source of the water has any effect on the ^ Bow, I T * B*, Gil field emissions, of IT*, M l * 250, Cl§2&|* x Johnson and Bernard, Flan for gaging: individual wells, Trans*, Am*. Inst*. Mining: Engineers, vol. 57', pp. 1050-55=, flSlLTl. 26 emulsion formed* Swabbing tests on weilsr fetfe shown that crude; petroleum often enters the well as an emulsion* It is doubtful if this is formed very far from the hole , since the sand: through which it must pass Is? more apt to act as a filter and break the emulsion, than t# aid in its formation* l&nulaif I cation that takes place: In the well depends largely on the type of equipment used to recover the oil* The common vertical type of oil well pump is posiefhle of farming emulsions by the churning action of the plunger In the working barrel* 011 is also emulsified in the tubing by agitation of the rods* leaks ± r k the tubing allow' oil and water to be forced out into the casing, probably emulsified,, to drain down and enter the pump* Wells, flowing because of high gas pressure, f orm emulsions rapidly* Wells, using gas or air lifts, because of the increased agitation, yield stable emulsions high in water content^* Wells, producing by aid of applied vacuum, show no increased water trouble5* ^ ®as-Xift lief hod of flawing Qil Weils by H. C* Miller, b*S*B* Of If*, Bun; 52b, pp* 35-d, glSSOj* 5 Effect of Taeuuni on Oil Wells by LIndsly and Berwald, IF*S*B* of If*, Bail* 522, pp* M-h, £X95d|* Paraff in and dongealing-0iI Problems 27 The oil-water emulsion is the type of colloid to re ceive greatest at tent fan from oil producers. Crude petroleum contains colloidal paraffin and asphaltic matter, which may require removal in the process- of refining, or it may coalesce and separate during: certain operations to the detriment of that process:- These gums, waxes, resins and asphaltic materi als may he in perfect solution at a certain temperature, or they may he dispersed in fine particles- The slightest change in pressure of temperature will cause coalescing of this ma terial, followed in many cases by deposition about the open ings into the well casing, upon parts of the recovery appa ratus, or in storage lines and tanks* Other factors; controlling the farm of the material are the amount present, the amount of gas in solution, the amount of water present, the amount of fine sand and silt, and the amount of the various materials present - The problem of maintaining colloid, until it can he handled to best advantage, is different with each oil, and different as the methods of recovery differ- A thorough study of the crude petroleum: is necessary before remedial measures can be taken* Although wax may separate from the emulsion, it need not settle on the sand, well casing, pump, or other equipment, as the wax is lighter than the oil, and should he carried along in the oil. stream- The greatest cause for wax accumu lation is the alternating wetting and. draining of a surface by the oil* especially if the surface is cooler than the critical point of wax in solution* Mowing: wells * in which there is a great deal of gas* carry the oil out in fine parti** eles* and give the wax good opportunity to coalesce* When this wax attaches to a metal surface, it sticks fast* Pooling; within the oil itself * due to several reasons* causes separation of the wax* The cooling may be produced by evapor&tion* gas expanding* heat lost through radiation as if moves from: the sand to storage* or due to change of tempera ture of water entering the ail zone* In case of excess paraffin in the crude petroleum, its trouble may be eliminated by one of two general methods* by applying methods of production which do not allow the wax to separate or collect where not wanted* and by removing any wax that does form before it can seriously hamper efficient oper ation of the recovery equipment* fhe first method is often difficult* and the second often costly, but the expense is met through an increase in the rate of production and greater efficiency of well operation* In flowing wells* the loss of gas represents evapo ration from the liquid* The physical process cools the oil^: hence* we have a cooler liquid of higher wax concent rat ion* This condition can best be regulated by increased bach 29 pressure, although it often requires change in size of casing, a different flow “ bean, or a combination of two or more of these condltions* It is not always possible to prevent wax coating under these conditions* In such cases, care must he given to proper removal of accumulated wax* (fee and air lift wells present similar conditions, and require treatment simi lar to flawing wells* Pumping wells offer two problems! The problem of the new well in its transition period* and the nearly depleted well in its aid age when its flow is small* In the first case, the wax accumulates primarily because of reduced temper atures caused by lowered pressure* In this case, agitation should be eliminated* The well should be pumped slow enough to insure a constant steady flow, thus keeping gas from entering the casing or separating from the oil in the string* The sucker rods and pump should be set to eliminate whipping of the rods* and hence, eliminate agitation from this source* These wells are easiest to control* Should wax accumulate, the equipment should be heated* Steam can be used at times, but most efficient methods use hot oil pumped into the sands, or an electric heating coil lowered to the scene of the trouble * Wells pumped in their old age offer little trouble* The gas has been dissipated* hence, their flow is constant, although slaw* The ail becomes cooled an its upward passage, hut not enough to cause serious trouble*, fee chief source of trouble may come from closing the well down for a few days, or from a leaky foot Taira * Faraffln may collect in the sand or on the face of the sand* This is generally caused by too fast a moTement of the oil into the casing accompanied with reduced pressure and lower temperatures* This greatly impairs the efficient oper ation of the well, and should be controlled wheneTer possible*. The methods for remowing paraffin are tor f e e at when possible, or to treat with suitable sol went*. Some chemicals are used, but not with best results*. If the aolweht is not too Tolatile, it is well to use it as? hot as possible % Where these? methods fail* reamers, drills, and. scrapers can be? tried* In extreme cases, explosives my be necessary* Explosives have been used satisfactorily in the sand to open new channels for the oil to flow to the casing* Asphaltic base oil or nsphthene base oil often present* cases similar to ^ wax problems. These oils- congeal to viscous? semi sol id massies* and rep resent another type of colloid* The treatment of this type of Oil requires lowering of the vis cosity by some heat treatment* Many oils are of the congealing nature, and also eon— tain wax* The oil may be a mixture of the two types?* How ever, the treatment is practically identical* The e-H trxmi the watted ha® settled may still contain some emulsified water as: well as: f inely divided parti cle® of clay dr sand remaining in suspension* In emulsion®, there: is a concentration at the surface of mm phases hence* the surface layer would hat give a goad sample for determin ing the composition of the entire body*. Even with the most stahle emulsions, there- will he a certain amount of settling of the water phase and of the suspended solid particle®* This causes a goring or concentration of inq^uritie® towards the hottom- of the tanlc* it can he readily seen that true ©ample® should: contain, proportionately samples from various levels in the ad!* The ail thief doe® this hy admitting oil to the tuhe of the thief a® desired hy the gager.. Free Water Testing Free water may often he; determined hy placing a few drops of oil on a glass and tipping the: glass s o : that the oil spreads out* Free wafer will generally separate in small drops* This test* While single* require® dionsiderahle care and experience* g & method for gaging: oil and water at wells* Cali fornia State EinSng Bureau* BUli* St* pp* 8£-S€* It is often desirable to determine the amount of free wafer which has separated from the- .od3L and lies on the bottom of flie tank* Far this purpose, water finding devices are need!., Some of these are simple and yet accurate* One of the best methods is* to fasten a strip* of prepared paper fa the stick or plumb bar*, The paper is coated with a yellow substance soluble in wafer but not lit o i l . * , d simpler method, and one which may yield accurate results;* im to coat the stick or plumb bar with chalk before or after lowering to the: bottom. & wooden stick may be coated after* but metal should be coated before lowering*, The metal stick* coated before* series well for light oils* Other methods are. arrangement of pet cocks at internals near the bottom of the tank* which may allow determinations to be made within certain limits;; use of ebony sticks, which are: wetted by water and not by oil;: careful use of the samplers o il thief £ and coating the stick o r bar with some thick sugar syrup, which is soluble only in the wafer*. Fef raleum BmfEsion testing’ Testing: for ifaulsifled. Wafer and Suspended Solids* Samples: of crude petroleum are tested for wafer and suspended solids: in several ways*. Each method has its advantages and limits*. The two most common methods; are centrifuge and distillations the former often does not separate ail of the water* while the latter method does not give determination of 33 solid matter* The Centrifuge may he used in the laboratory for testing7 the percentage of water and solid matter, or it may he used; in the field to separate impurities from the oil commercially* This is true for practically all apparatus* Laboratory centrifuges are carefully- built machines, which re— voire at high speeds* It is necessary that the machine he in perfect balance, whether it is being used or not* The manu facturer has the machine in balance when it is turned out* The operator must maintain a balance by keeping the added liquids of equal weight* The action of the centrifuge is to force matter away from the center of the revolving plane* The heavier substances are acted on stronger than lighter substances;, hence, water and solid substances are forced out of the oil* This force is similar to the force: of gravity acting on a still body of an emulsions but centrifuges in crease this force hundreds of times* If an emulsion will break from standing, the centrifuge hastens the coalescence. The centrifuge simply increases the force acting on the densi ty of the matter, and draws it out of the emulsion. There are electrically and hand operated centrifuges* The best type for petroleum work is a high speed electrical machine. 7 L* C. Uren, ^Petroleum Production Engineering*, pp. 47T-78* m In all. cassae* a graduated glass tube* tapered on the lower end, is used* If the tubes are not. of the same weight* the machine can: be balanced by adding nore of the •Oushoning* liquid to the centrifuge tube bolder* Feperding on the stability of the emulsion* de-emulsifying agents:, should be added to aid in separating the iater> Chemical reagents soluble in oil. and insoluble in water are best* A mixture of half gasoline and half carbonbisulf ide is most commonly used* There are also several commercial products which may be used* For the hist il lat ion Test. a special apparatus designed p t by the F* S ' * Bureau of Mines0 has been Used* This apparatus gives an accurate test for the amount Of water present, al though the solids must he determined by other methods* The feature of this apparatus is a special, graduated receiving tube which catches the water and holds it in its lower part* Oil will fill the balance of the tube, and the overflow" will run bad: into the distilling flash* The operation of this apparatus requires a great deal of care in heating* The Mat must he applied slowly or else puking* as in commercial heat treatment for water separation* will result* A porous ring is used on the bottom of the flask* but better resULts have been obtained by inserting a coil of wire screen in the Outlet so that it just touches the top of fM liquid* 8 e . e . r n o m $ e K i s a , CisiaK With this method, it i s; advisable to : add an amount; of solYenf up- to the amount, of sample: to he: tested*, The solvent should have a boiling point midway between that Of the oil and that of the water:- The mixture: is heated to- a temperature slightly above: the boiling point of watery and held there until alX of the wafer has been distiXXed over- Some of the solvent is also disrfeiXIed over*. hut it catches in the wafer gage or fXows: back, if that tube- is full- The: solvent re duces the boiling point of the water in the mixture* and re duces the viscosity of the emulsion* which allows the water to free itself more readily* Other Tests for Crude Petroleum: I5nulsions- The Test: for Density is usuaXXy spoken of as: the gravity test* It is usually made, hydrometer weighted' to read within a small range of the oiX to he tested* and equipped with a scale: reading in tenths' of a degree j£-FvI- scale - The inst rument used in the oil industry contains a thermometer to give temperature: read ings: In degrees Fahrenheit- The temperature reading is necessary * as gravity is reduced to 6 € t degrees Fahrenheit as a standard- The- operation of determining the density is simple - & hydrometer Jar is filled within two or three inches from the fop- The hydrometer is placed in the liquid and allowed to sink slowly until a position of equilibrium is nearly reached* Xf is then immersed below this posit ion* and allawed ia< rise hy its: own buoyancy t© equilibrium* IF the ail is dear* the reading should be taken at the under aide of the meniscus* Bubbles and? foam should he broken if the reading- i s : to he taken from above the surface. This: can* he done hy applying: a drop at either benzene or earhunhf sulfide to the hydrometer just ahcre the liquid surface* ¥iseositg Beferminatfdhs* Because practiceXly all oil t ranapo rtat ion is. through pipes, the viscosity or internal- friction is- an important factor to; know. Oil clings to the' inner surface of the pipe forming a , film* Another film: clings to this film*, and so on towards the center* The resistance to flow is its measure of viscosity* Tables II, III and IV of this- paper show- the relation between water content of the emulsion and viscosity* It is seldom necessary to: determine the: absolute -vis cosity in dyne seconds: per square centimeter; units* This unit is called a poise* There ere several commercial vriaco:- simeters In use* It is necessary to state the -viscosity in numbers of seconds, the name of the: instrument,, and the temperature in degrees Fahrenheit at which it was taken or calculated* Bach Instrument consists of a container Of defi nite size with a email, opening at the bottom which can he closed* The container is surrounded, hy a jacket containing: a . suitable liquid to raise the temperature to the: desired point* The instrument is equiped: for heating with an electric coil* Eat water, or steam- When the entire system has been brought to the deaired temperature* the cert is pulled, a stop watch is- started* and the stream allowed to flow into a container* When a definite amount of the liquid has run into the con tainer* the steep watch is stopped and the reading taken* A chart for any liquid can he made showing degrees of tempera ture and seconds of time by establishing a few points* From this chart* the viscosity at any given temperature may be determined* Surface Tension is a property of liquids, and is of special interest when applied to emulsions* Many authorities believe that it is the difference in surface tension of two liquids that allows them to peptize on agitation* This be lief is based on the knowledge that the substances which aid emuleifieatiom produce a lowering of surface tension* In studying the properties of emulsion* it is well to determine its surface tension* it is also advisable* in many cases* to determine the surface tension of its component parts, when these can he separated without adulteration* Surface tension® is noted as a liquid forms a sphere* or as a liquid moves up a capillary tube* Still another demonstration of surface tension is its tendency to form a ^ E« B. Millard, Physical Chem* for Colleges, pp* 76-7- ring: with the sprface of the liquid as a metal ring is; with— drawn from the liquid* These, eases form the 'basis; far* testing and measuring: surface tension*. Surface tension: is measured in dynes per square centimeter* If a ring is dipped in: m . liquid and elowEy withdrawn^ a f ilim will farm in the ring* The fame is exerted towards the center of the ring:* It is opposed to the fame that is polling if from the surface^ and: is generally measured on a dial attached hy levers- to thO metal ring* The rise of a liquid in. a capillary tube * which, is wet by the liquid* may also be used as a measure of surface tension* The measurement is taken as that force which forces a column of liquid a certain distance ah owe the surface of the liquid* Richards*^ developed an apparatus: for measuring capillary rise which is both accurate and easy to operate* A drop of liquid frees itself from a . rod or tube? when its: weight exceeds its surface tension^ which is holding it to whatever it is ding ing to:* There have been several, formula developed to de termine the actual weight of the drop as the surface tension is broken^* Of the several methods,, the one most suited to 10 Bfe&ws®*, J. Are- Ghem* Sec*. 3Tt, XSm* (1915?. Harkins and Brown. . 1* Am* Ghem*' Soc*. CL. 439?* laboratory determination is the metal, ring method* There are several pieces: of apparatus using: this: method ; : some are simple and allow only am approximate determination * while others are more highly developed and' are capable of c omparat i vely high accuracy* the capillary rise method and the falling drop method are capable of highly accurate results* hut their operation is more* difficult and requires greater experience. Absolute Measurement s of Are rage Size of Droplets* Davey^ working in the research laboratory of the General Electric Company, developed; a method of making; absolute measurements: of the awe rage si ze of droplets' of the; disperse: phase of an emulsion* The method is similar to the method Langmuir used in measuring the size of molecules. An enameled, iron tray about eight inches wide * thirty inches; long, and two inches deep* is filled half full of water* A piece of paraf fined aluminum foil is floated at one end and is attached to a balance* The rest of the surface is swept clear* Yoids are eliminated by pushing the film up against the foil* The area is then determined as in the langmuir experiment * In calculation r it is necessary to know the total volume of the droplets as they existed in the emulsion:* The volume may be found by curdling a known volume of emulsion with a known volume of solution of a suitable electrolyte, removing* any included water from the curd" and adding it to the rest of the water phase* The total volume of the water phase is then measured* and the volume of the dispersed phase is found hy difference* This gives at once the concentration, C, of the emulsion* The average diameter of the droplets of the disperse phase in the emulsion is d - * where ¥ is the A volume of the emulsion which was spread' on the water, and A is the area covered* Photomicrography * In making measurements and tests of various kinds, it is often desirable to make some permanent record* The droplets of emulsions in nearly all cases are microscopic in si set hence, do not lend themselves to simple observation, as many substances do.- Emulsions may be observed under most any microscope capable of magnification of one hundred dimensions* To make the record permanent, the camera has been used to photograph through the microscope*^* Photomicrography*^ is a subject to which one could de vote many pages* The subject will not he covered in any de tail in this paper, but a few points on procedure; as applied to photographing emulsion globules will be discussed* ^ Chamot and. Mason, ^Handbook of Chemical Microscopy*, (1924). 14 *Ph aiomicrography*, Eastman Kodak Comparer* 41 The microscope to b e: used should hot: he part of the camera.* The connection is made with a matte black light weight connector# The camera may be any available* If it is equipped with a lense, the lense should he focussed at in finity# It is simpler to use; a camera without a lense. The important item in procedure is to obtain the proper lighting# The light may be from an arc,, a tungsten lamp* or the ordinary house lamp. In event of the tungsten lamp, filters may be used# In fact, it is often necessary that they be used to tone the light* Filters of different colors intensify or eliminate detail and contrast, A great deal of skill is required get the proper lighting and ob tain the maximum results from the use of filters* The best rule in this case is to try the various filters. As a rule, colors in contrast to the color of the emulsion will intensi fy the contrast* With*- the microscope in proper focus, and the lighting arranged for clearness to the eye, the camera is put in place to record the image* The plate position is set at the micro scope eye piece focus as marked oh the eye piece. This, in most cases, is ten inches* A ground glass is placed in the same position to be occupied by the photographic plates; and the image, brought to focus on the ground glass by means of the focussing screw of the microscope* To gain greater clearness, many ground glass plates have a spot of clear glass at the center of the plate* By using a hand lens:e;t a clear sharp image may he brought into focus on the spot of clear glass in better* detail than is possible on the ground glass* The degree of magnification depends somewhat on the material under observation* If the thickness- of the oh ject Is very great f the magnificat ion can not be as great as for very thin objects* as the entire object should be in focus* Skill is only developed with a great deal of prac tice * The operator will develop many new rules and refinements of the various steps as he proceeds with the work* CHARTER TW E E ^ E M im S iF Iit^ IO T OR ESMYBEATIOIT OF &mm FE TROUSIM It is not universally true to say that all crude patroleum must he treated for water removal* but the cases; where the water canient is below the? allowable amount are ex tremely rare* Sooner or later * every field: will present its* water problem*. In those cases- where the oil has been clean during: early production® the first signs of water will be free water produced from boarder wells* later* emulsified wafer will appear*. The oil must he dehydrated* History*. The treatments of crude petroleum emulsions hare taken much time and study to develop* Treatment of emulsions started more or less by chance. It Was only a few years ago that the heavy emulsions or cut oil* as it is known in the field* was a waste product* and a product that was ex pensive to dispose of. Early methods were to dump* it into streams* rivers or lakes. This method received just condem nation from anglers* nature lovers* and the public alike* The next simplest method* was to run it into sump holes where it might be burned after a certain amount had accumulated* Before the burning process went long* someone noticed that some of the Oil separated on standing* and could be recovered 44 by skimming* The next move by those interesrted was to run it on large spreading sumps., where it could stand and be warmed by the sun- This "sunning* gave a hint of applied heat, and it was not long until steam coils were used, and the oil was kept covered to eliminate evaporation losses* The next move was the use of stills* Sometime along this route, chemical treatment was tried* The first trials were cruder lie and lime were used with fair results in certain cases* W* S* Bamiekel made ex tensive studies throughout the Gulf and Mid-Continent fields, and became convinced that chemical treatment could be suc cessfully carried out* He developed a compound of various oleates with a small amount of phenol, which he sold under the name of Tret—O-Lite* This method was: successful with eastern crudes* The method, with certain refinements, is still extensively used* There was in existence at that time, a method of breaking smoke and vapor colloids by the use of high voltage current* The patents were held by Cottrell and an adaption was made for the breaking of crude petroleum emulsions* This method was successful with Gulf, Mid-Continent, and California crudes where the chemical methods were not sc successful* The cream separator, using centrifugal force to sepa rate two substances of different density, prompted the de velopment of the centrifuge, which has been used with varying 45 degrees- of success In all parts of the country. Methods. These methods, heating, chemical, electrical, and centrifuge, are those used to any extent in the Industry today* Certain producers use one method, while their neigh- hors use another, yet, we find many producers using a combi nation of two or more methods* The factors, guiding in the selection of a method, are several, and require a careful analysis of the oil, product desired, supplies available, and cost of operating the differ ent methods in that locality. Evaporation, especially with light oils, is an important factor, yet, heat treatment of a few degrees is often sufficient to cause separation of the water. Often, the oil Is heated, treated with a small amount of chemical, and then centrifuged or treated electrically* In most cases, if the product from the well is allowed to stand, it will separate in three layers* ITater is the heavi est and will be on the bottom; a layer of emulsion or B.S* will be above it; and a layer of clean oil will rest on top. The three are run off separately and used, treated, or dis carded, as the case might be* Settling or Sunning Process. This process has had little or no development since its first use. The oil is run into a shallow sump. There may be several such sumps, and the skimming process may be progressive. The handling costs 45 of the oil are low, but evaporation is high** Also, valuable asphalt compounds are completely lost in bottom sediments. The cost of holding and storing the oil is also high* Where the oil yields to rapid settling, tanka may be used* These tanks may be covered to reduce evaporation losses, and may be arranged in series for more rapid separation* This arrange- ment is adaptable to use of one or more steam coils, and even a certain amount of chemical treatment* Heat and chemicals speed up the action by lowering the viscosity and breaking the film about the water droplet* Where evaporation losses are not increased, heat and chemical treatment reduce the ex pensive time element of settling* The B*S*, not lending it self to treatment, is often hard to handle and must be dis posed of* It is sometimes burned to furnish the heat used in the process* Dehydrating by Heat* The losses encountered in the settling process will exist in all cases of open heating units;* Evaporation losses are exceedingly high* Steaming plants have been used extensively^. The process is to flow the oil through several tanks in the bottom of which are 1 3m H. Wiggins, Evaporation Loss of Petroleum in the Mid-Continent Field, U*S*B* of l f f . t Bfcll. 2QQ, (1922)* 2 I* C* Allen and W* A* Jacobs, Methods for Determin ing of Water in Petroleum, U.S.E* of M*, Tech* paper 25* 47 steam coils submerged in salt water* The area of contact be tween the salt water and the oil is greater than if the oil was only in contact with the coils. The oil enters the tank: at the bottom and flows up through the hot water* It is collected at the top and sent through a pipe to the bottom of the next tank, where it receives like treatment* The hot water, besides heating the oil, gathers the free water and fine solid substances., Overflow pipes keep the water at a constant level* Hot air has been used in certain cases of indirect heating* Hot compressed air may be heated to a higher temper ature than the salt water* The air is liberated from pipes on the bottom of an oil tank* Some of the emulsified water is heated and becomes steam* The steam in turn helps free other water* The water collects on the bottom of the tank and is later drawn off* The cost of this method is exceeding ly high, and has been used in but one plant to the writer's knowledge * A third heat process, one in which direct heat is applied, similar to distillation,is often combined with some tapping of lighter fractions* The oil may be heated in tank stills or tube stills* and the process may be continuous or by the batch* The cost of this process is also comparatively high, as are all heat methods. 48 Champion** developed a simple method of heating an emulsion, and allowing it to separate, following the laws of gravity. Turner* developed a similar process dependent upon hdat as the emulsion Breaking agent. Van Loenen^ used verti cally inclined tubular retorts which he heated with either oil or gas Burners. The process uses the waste heat for super heating steam which, in turn, is used to preheat the oil. Heat methods find widest use in isolated areas where power is not available, and where the cost of importing chemicals would Be high. Heat methods were discussed, Be cause, in nearly all of the processes, it has Been found that a slight rise in temperature will produce economical results. Emulsion Breakers. There are several physical process es of Breaking emulsions. The most common and widest used of these is the centrifuge, of which we will speak later. The other types depend mostly on directing the flow of the ail through pipes, over Baffles, or through filters. Hearly all of these methods require a small increase in temperature. 5 Wilburn B» Champion, U.S. 1,945, 367-8, Jan. 1931. 4 John B. Turner, U.S. 1, 948, 481, Feb. 1931. Wu. F. Fan loenen (to Petroleum Rectifying Co. of Calif.) Oct. 24, 1931. 49 Ravoiney and Hunter used a heat treatment and directed flow to break difficult emulsions6* An emulsion is caused to flaw in a loop-formed stream, as through an aperture compris ing a long* dauhle-chamhered pipe* and the stream is sub divided at the turn of the loop into a plurality of parallel fractions* and succeeding volumes of each fraction are caused to rise through pools of the heavier component percipitated from antecedent volumes of emulsions* and accumulated in the paths of the subdivided stream* while heat is applied to such pools* Eayuk directed the flow of the emulsion against itself for its dehydration^* The emulsion breaker consists of a set of tubes 15 m* long and 5 and 5 inches wide * the latter being concentrically placed in the former* The emulsion is passed through the Jacketed space formed by the two tubes, and steam is passed in counter current to the oil through the inner tube* The emulsion is warmed to 160° as it passes to storage, where the crude oil separates from the water* Tan Loenen recently developed an apparatus* having a rotable horizontal drum* for continuously resolving emulsions, such as those of petroleum by treatment with granular solids 6 Thos* A* Fovotney and louis F. Hunter (to Fat* Radiator Corp.) H*S* 1*968, 614* July* 1931* 7 S. E. Eayufc, Eeft. 2, Ea. 9-10, 20-1, (1931). 50 such, as sand®. The same worker, aided " b y Garrison, agglomer- ated the dispersed phase of an emulsion by passing it through a porous mass of comminuted AlgO^ crystal• Chemical Dehydration*. In studies of emulsions, it has been found that the emulsifying agent may be responsible for the dispersed and the dispersing phase* Certain chemicals cause a conversion of the phases* In oil and water emulsions, the film may be broken by lowering the surface tension of the dispersing oil phase or by strengthening the water dispersed phase* Those reagents in which petroleum is highly soluble, as ether, benzene, or carbon disulphide*will lower the tension of the oil and free the water. The water soluble chemicals are several* One of the basic treatments is the use of the alkali colloids such as sodium and calcium stearate and oleate. In 1919, the basic patent covering the water-soluble alkali salts of sulfonic acid was granted F. K. Rogers. These alkali compounds form a colloid solution in water which re sembles a crude soap* There is no colloid solution formed in the oils* To the water colloid, a small amount of sodium salt of a sulfonated mineral oil, along with some heating will ® Him* F* Tan hoenen (to L* Blake-SteithJ T3*S. 1,967, 601 July 24, 1954* 9 / Murray R. Garrison and Fin* F* Tan Loenen (to Petrole um Rectifying Co* of Calif*} U*S* 1,947, 709, Feb. 2, 1934* cause the water to separate * Preservative colloids^0 have been used to reduce the viscosity of mud slush* The process is to reduce the concen tration of calcium and magnesium ions helow the floculating valueand neutralize the floculating effect of the alkali hy use of the preservative colloids* * r * j WalkerAA used a de-emul s ifying agent containing an alkali salt such as the ammonium salt of an alkylated poly- cilic sulfonic acid* toother type of sulfonic*^ acid has heen recovered from refining of white oil* It is a mineral oil sulfonic product, of the type recovered from the refining of medicinal white oils* etc*,, with strong or fuming RgSO^, with alcohol as a viscosity reducer* reagent disperser and eoaleseeut accelerator* Still another sulfonated producr^ is s i complex condensation product precipitated from a sulfonated aromatic amine such as sulf onated aniline * and an alc ohol of aldehyde of the aliphatic series* Considerable success has* been had with water-soluble colloids: which neutralize the effect of the emulsifying agent ^ C* Wlrfh* III * Pet roleum Times 31, 225, (1934). ii C* Walker (to Expire Oil and He fining Co* } I F . S. 1*944* 021* Jan* IS* 1934* Chas* Fischer Jr* and Warren T* Reddish (to Kontrol ©c**) B*S. 1*941* 886* Jan* 2* 1934* ^ Truman B. Wayne * U.S. 1 *93? * 259* Fov., 1933* 52 dissolved in the ail- *Tret-G-Lite* is such a compound* Fhen first put on the market,, it had a consistency of soft soap* Later* a liquid was developed* The first product*^ contained 83 per cent of sodium oleate* with small amounts of sodium resinate, sodium silicate* phenol* paraffin and water. Approximately one part in a hundred in a water solution was added to the emulsion which was held at a temperature of 15Q°P. for from twelve to seventy-two. hours* Usually the water con tent was lowered helow one per cent* The liquid product con tains at out 25 per cent of sulfonated oleic acid* JLny excess acid is neutralized with caustic soda* The amount of chemical and time of treatment depends on the properties of the oil* The procedure is to mix the chemical with the oil as. it is heing pumped into a tank containing hot water* The separation takes place in this tank* Later developments of this product have heen made hy Kelvin Be Groote and others* Sulfonic acid or sulfonic acid ester such as the sulfonic ester of acetyl alcohol—— or its ammonium salt— has heen used as a de-emulsificating agent* They also used the sodium salt of a sulfonic acid derived from laurel alcohol-1 - 5. Other sulfonated derivatives have heen ^ L. W* larsons* J* of Xnd* and. Bhg* Chem. * Vol. 13* pp. 1008-101?* Fov* 1921* 15 * Melvin Be Groote and Maui's !. ffonson (to Iretolite Co.) U.S. 1,938, 322-3, Bee. 5, 1934. secured from hydrogenated: castor oii^>. Developments? by Be Sroote and WirteX^ produced: a de- emulsifying agent which: contained a subs tant ially anhydride sodium salt of a naphthenic acid*, produced from naphthenic acids: of a molecular weight of from 200 to 575, a mean mole cular weight of about 225 and a distillation: range of from 250° to 3X0°, mixed with a relatively small amount of an un- neutralized naphthenic acid of the same hind. Still another agent may be a mixture comprising: not over 40# water* material produced by partial neutralization with of naphthenic acids as specif led in the above compound* and about ah equal amount of a . water-soluble ammonium salt of a butylated naphthalene sulfonic acid* Differing only slightly is a mixture containing not more than 40# water together with a water-soluble ammonium salt of a butylated naphthalene sul fonic acid, and. a product derived by the partial saponifi cation of oleic acid with HH^OH diluted with 25# kerosene, or similarly an oil-soluble, water-insoluble petroleum sulfonic acid is used instead of oleic acid* Other agents used a mixture which may comprise a product obtained by hydrolysis of sulfonated castor oil together with a . water-soluble salt - i n . . . n i l . 1 1 i i i i.i. ■■■ i ■ i ' Helrin Be Sroote and Louis T. Hanson (to Iretolite ©B»> B*S. 1*940, 39©* Bee. IS* 1934. ^ BbItIh Be SRKtte and Arthur F» Wirtel (to fretoliie Go.) U.S. 1*940* 391-4* Bee. 19, 1934. 54 of a "butylated naphthalene sulfonic acid, in specified pro- portions:, and one comprising an oil-soluble, water-insoluble petroleum' sodium sulfonate, a modified fatty acid product, partially saponified with BH^OK, dilute alcohol and a hydro phobe solvent such as kerosene, and neutral compatible salts of ivory* Acids in specified proportions are used* Be Gfroote, alone, developed^9 an oil and water-soluble de-emulsify ing agent containing not more than 40£ water, to gether with a dialkyl polysulfonate ammonium salt produced from blow gas tar by reaction of Hj jSO^, and substantially, an equal amount of a naphthenic acid or naphthenate material* He also developed a de-emnlsificating agent using a similar naphthenic acid or its salts, together with an BH^ compound of a petroleum sulfonic acid substantially free from polymer and non-sulfo type hydrocarbons, and derived from Gulf Coast naphthene crude oil by multiple acid treatment of the kind in which the first acid drawoff is discarded* Still another de- emulsifying agent contained the sodium salt of a sulfonic acid derived from tetradecyl alcohol* Other chemical processes depend on adding some salt to harden water* One such compound-^ contained a mixture of a Melvin Be Sroote (to fret elite Co*) M.S’ . 1,940, 395—6, Bee* 19, 1934* ^ Abraham M* Herbsmaim, (to industrial Patents, ltd*) U.S* 1,959 , 824, May 22, 1934* 55 sulfonated fatty glyceride , an inorganic alkali earth salt such as CaClg and a suitable solvent* There are many chemical processes of greater or less merit* Some of them are good in their entirety, while others have hut a few good features* Oil and water emulsions will always demand chemicals for their breaking. Chemicals are always more active with higher temperatures, and best results are obtained by heating the emulsion before the treatment* The great difficulty of using a water-soluble substance is that of passing it through the oil film which encloses the water globules* Agitation partially accomplishes this, but good results have been obtained by adding phenol to the chemi cals* Considerable phenol is required unless it is accompa nied by a strong acid* Dehydration by the Use of Electricity* Emulsions have been subjected to ionizing rays, such as ultra-violet, Rontgen, cathode, or radi-active rays to split the enveloping film2* * . A new line of electric emulsion breaking has recently been developed2^* The apparatus developed consists of two concentric electnodes, the outer, a metal pipe, and the inner, Abraham KT* Herhsmann, Germany 592, 877, Feb* 16, 1934 (cl 236 1.05)* 21 Electric Condenser Process of Be-l&nulsifying Oil — R* J* Biersal — 111* State Geological Survey, Rept. Investi gations So* 29* 56 a copper wire enclosed in a glass tube* This glass tube acts as an insulator to prevent the passage of current through the oils only the electric field is set up* A commercial unit operates off of a six-volt storage battery with a model T Ford spark coil. It has a capacity of one barrel per hour* Tests show that the three worst emulsified oils in Illinois can be broken down to less than one-half of one per cent or water by applying this treatment at 8Q°F. It is fire proof because of the separation of the electrodes* A lengthy dis cussion of other electrical methods is given* The efficiency increases at higher temperatures* but 80° was found to be the optimum temperature. The essential feature of the electrical dehydration consists of coalescence of water globules due to their movement under the influence of an alternating field? hence, viscosity has quite an influence upon the speed and travel of these water molecules* Lawrason developed an electrical apparatus for breaking petroleum emulsions by vibratory and electric treatment. The vibratory motion was intended to set the globules in motion for more rapid breaking* The electrical process in greatest use, and the one which forms the basis for most of the developments in electri cal dehydration is a process based on the Cottrell process for removing dust and soot particles from smoke* The process is controlled by the Petroleum Rectifying Company of Cali 57 fornia* The method is known as the high potential alternating current method* In some modifications, direct current has heen used* When direct current is used* lower potential is permisaable * The method, now well established, uses an apparatus con sisting of a tank, revolving electrodes and machinery for re volving the electrodes, and controlling the flow of the oil* The tank is approximately three feet in diameter and eight feet high, and stands vertical. The tanks are usually steam Jacketed so that the process may he aided with an increase in temperature* Supported on a vertical shaft from a thrust hearing are from three to five discs which revolve with the shaft* The discs are symetriealiy placed to allow space be tween the discs and sides of the tank for the electrical gap* The shaft and discs are made one electrode, while the tank is the other* A current of approximately eleven thousand volts is used* which establishes a strong electrolitic field as chains of water globules are formed* The discs, besides giving maximum area on their circumferanee, serve to agitate the oil as they are revolved* The revolving of the discs and agitating of the oil keeps short circuits from being formed* The oil enters near the top of the tank, and must flow through each compartment and past the gap area between the edges of the discs: and the walls of the tank* The oil may be heated before entering the trenter, or while it is being 58 treated. The heated oil has a lower viscosity which makes it more mobile and better suited for treatment* The oil and water leave from the bottom of the tank* and are sent to settling tanks where the separation is completed* An over flow pipe at the top of the tank may remove some of the oil if the inflow is too great. Blectrieal dehydration is responsible far the separa tion of oil and water in the largest part of our crude oils. The process is easy to control* rapid in action, and economi cal. A treater, as described, is passible of treating from three hundred to sixteen hundred barrels a day , at a cost of from a cent and a half to three and a half cents22. Dehydrating by Centrifugal Devices * In the chapter on testing emulsions, the centrifugal force acting on liquids of different densities was discussed. The effect of centrifugal force has long been used to make separations of oil and water from crude oil emulsions. The process has: been applied to separation on an economic basis. While the testing process is a small batch process, separation of oil and water in the field is performed as a continuous process2^. The machines used for continuous separation must oper ate at high speeds, and may be driven direct from electric 22 Petroleum Rectifying Co., Los Angeles, California. 2% J. L. Sherrick* Oil field emulsions, J. Ind. and Shg. Chem., vol. 18, PP* 133—139, Peb. 1920. mat are or steam turMnea, or they may he driien with belt or chain drive* The machine itself consists of a metal bowl mounted on the upper end at a vertical spindle* The liquid is: disehargsd from a pipe into the bowl at its center near the bottom* The feme anting: outward nausea the water* be~ cause it is heavier,, to separate and rise toward the top at the bawl* i t clear mark of oil and water separation then exists- The water finds an exit through holes near the outer edge of the bowl* while the clean oil is drawn off from the center of the howl* iluch of the sand and suspended solids will he removed from the howl with the water* The coarser and heavier of the solid materials must he removed by hand when the machine is idle* There have been two developments of commercial centric fuges* One type closely resembles the milk separatorr using but one open bowl* The other type has a series of thin sheet metal cones mounted one over another on the central spindle. The liquid to be treated with this latter type enters the howl at the lower center, and is forced by the centrifugal force up and between the cones. The water,, being heavier, forms a thin sheet on the under side of the cone• The oil forms a sheet on the upper side of the cone. Suitable outlets are so placed as to allow the separated oil and water to be removed. Bach: process has its particular merits, the listing of which would require considerable data to substaneiate. The process: using the multiple cones: can he operated' at iewr speeds than the single free? howl: process* Centrifugal processes are greatly aided if oil is pre heated and chemically treated. In reality* the centrifugal process acts on the emulsion as settling would with far CHAPTER V EMULSIFIED ASPHALT The reason far breaking crude petroleum emulsions is to eliminate the cost of storage* transportation and carrying it through any of the refinery processes* There are reasons for forming emulsions of petroleum products as important as the reason for breaking the crude emulsion* The reasons for forming emulsions vary with the product desired* Certain ^soluble* oils are made for many uses. These soluble oils* already emulsions* can he easily diluted* and furnish a means of dispersing oil in water with the use of hut the simplest machinery. Cutting oils* emulsions also* are made and used to keep the temperature of cutting and threading tools telaw a temperature where tearing and gouging occurs from overheating. Creases are emulsions resembling soap in composition. Bituminous emulsions are made to put asphalt in a liquid form at ordinary temperatures:. Asphalt is the oldest known petroleum product. It was formed from distillation in the earth and left as deposits or seeps in rock formations. The earliest uses of asphalt were as calking in boat building* water proofing of all kinds* and as a preservative* especially in the preparation and preserv ing of mumies. The use of asphalt as- paving material is com- 61 62 paratively new, "but this use employs the larger part of the asphalt now produced- Roofing and preparation of *tar* paper — waterproof ing— also; account for the use of large quantities of asphalt- Asphalt is not more conveniently used for all purposes in an emulsified form- For paving and dust laying, asphalt may he more conveniently handled in an emulsified form- This fact has long heen known, and emulsified asphalt has heen produced for many years* TShen first used in this form, the emulsion was made at the point of use just before spreading, hut later developments have made it possible to make the emulsion at a central plant, ship and store the product without separation, until spread and exposed to the air. Emulsions,1 on account of their greater fluidity, have the advantage of being applied more cheaply than untreated oils, asphalts, or tars, thus enabling them to he spread on the road without the use of a special form of apparatus— the ordinary pressure sprayer being sufficient. They are adsorbed more readily by the road surface, be it either dirty or clean rock. The rock need not be dry, as it should be to receive hot asphalt, but may be delivered fresh from washing bins or wet storage* It is seldom necessary to interfere with traffic when paving with emulsified asphalt, and the job may be kept Herbert Abraham, Asphalt and Allied Substances, B* ¥an Hostrand Co- (1918). 63 cleaner with little tracking of the material by pedestrians. The emulsifieation is brought about through the inter vention of the following classes of substances? water-solu ble soaps,, alkalies, alkaline earths, sodium silicate, certain mineral oxides, plastic clay, tar distillates, including pyri dine bases, starchy materials, water-soluble gums, Irish Moss, sulfonated oils, casein, molasses residues, etc. The emulsifieation is effected cold. If a liquid product is to be obtained, the bituminous material and water containing the emulsifying agent are mixed in a suitable apparatus provided with a mechanical stirring device. If the product is to be produced In paste form, the emulsifieation is brought about in a •masticator* or a *pug-milln, in which mechanical agitation is coupled with a certain amount of grinding. Mechanical emulsions are obtained by mixing the oil with a suitable quantity of water, by a mechanical contri vance, just as it is about to be sprayed an the road, as for example, by means of a rapidly revolving set of blades. Oils, having a specific gravity nearing that of water, will answer best for this purpose. The following reagents have been used for emulsifying asphalts? 1. Soaps prepared from animal or vegetable oils and fats, which, when combined with petroleum, will enable that to be emulsified with water. One formula by L. S. van Westrum** uses oleic acid and ammonia. Rosin and rosin oil soap have been used by Wallbaum.3 Kasson and Saxton^ used a soap similar to that of van Westrum. 2* For those tars and residuum asphalts containing phenol compounds, the alkalies, including ammonia, caustic or carbonated soda or potash, borax, and slashed lime have been used with poor results* 5* The addition of a small percentage of certain alkaline bases, including pyridine, piccolin or quinolin, with asphalt or tar have given bituminous emulsions.^ 4* Colloidal vegetable and animal substances in small amounts have served as emulsifying agents* These may be most any organic substances, such as glue, gums, pectin substances vegetable mucilages, sulphite liquors, waste molasses liquors starch paste, Irish IToss and other glutinous substances dissolved in water. The use of many of these substances are 2 t. S. Tan Westrum* U.S. 992, 313, May 16, 1911. 5 Beinhold Wallhaum, U.S. 7,258, 103, March 5, 1918. H. B. Kasson and S. S. Saxton, U.S. 998, 691, July 25, 1911. 5 J. P. Van der Ploeg, U.S. 884, 878, April 14, 1908. 65 covered "by patents*® 5. Raschig7 used clay as an emulsifying reagent* Most any colloidal mineral substance would serve as well, such as metallic oxides, silicates* hydroxides or clays* Sodium silicate has been used by Hacking.® 6. Sulfonated oils, both vegetable^ and mineral, have been used* 7* Various waste products from the oil refining process have been used* Soda sludge and sulfuric acid sludge have been used with good results* Tfcylor*® developed an aqueous concentrated asphalt emulsion which can he diluted with hard water without separa tion, and which is not broken by wide temperature variations* It comprises asphalt dispersed in a small amount of water, by means of an emulsifier, such as green acid soap, together with a farinaceous protein material, such as cora-gluten meal or ® Earl Mann, U*S* 834, 830, Oct* 30, 1906; Carleton Bills, H.S* 943 , 667, Dec* 21, 1909* I f . A. Popkers, U.S. 1,240 , 253, Sept* 18, 1907* * * F. Haschig, J* Soe* Ghem* Ind* 29 , 758, 1910* ® Robert Hacking, U.S. 980, 513, Jan. 3, 1911* ^ H. R* Kasson and S* S. Saxton, 11*8. 998, 691, July 25, 1911* ^ Kenneth TUylor (to Standard Oil Co* of Indiana) U.S. 1,932, 648, Oct* 31, 1933* 66 soy "bean meal* Kutzenlauh** prepared stable, highly viscous hydro- phile asphalt emulsions by the preliminary mixing of asphalt with a small proportion of a concentrated solution of an alkali metal hydroxide or carbonate to neutralize free acid contained in the asphalt* and then mixing the neutralized asphalt with a quantity of water containing clay* and stirr- ing to effect emulsion* Sparks*^ also prepared a concentrated emulsion which can he diluted with hard water without causing separation, and comprises about 2 parts of asphalt emulsified in 1 part of water with an emulsifier containing green acid soap, together with Ha silicate or Ha^PO^* In Germany, Ackerman,*3 working with a double emulsify ing agent, developed a stable high percentage aqueous emul sion of bitumen, by the aid of soap and a buffer solution of PH, value of about 1G* More recent methods of preparing asphaltic emulsions have used hot liquid asphalt. The use of molten asphalt eliminates the process of cooling which reduces its cost. *■* Hagen Hutzenlaub (to Firma Paul Lechler) IT.S. 1,957, 408, May 1, 1933. Joseph W. Sparks (to Standard Oil Co* of Indiana) U.S. 1,956, 779, May I, 1933. *3 Wilhelm Ackerman, Germany 584, 540, Sept. 21, 1933. 67 Ifyers^ prepared a mixture of molten asphalt with a small proportion of rosin contacted under positive pressure with a stream of ITaGE solution, and the mixture then released from the pressure , heaten and homogenized* Another emulsion was prepared by adding a portion of molten asphalt^ to a hot caustic alhali solution while introducing saponifiable materi al, e*g*, oleic acid, and adding the remainder of the molten asphalt, all with agitation* A small quantity of colloidal clay, e*g*, beutonite, is added as a stabilizer at any stage of the process* 14 Da-rid IT. Myers, U.S. 1,957, 031, May 1, 1933. ** International Bituminous Emulsion Corporation, Brit. 400, 409, Oct. 26, 1933. CHAPTER. VI LABORATORY- EXPERIMENTS AND TESTS For the purpose of studying emulsions, a crude petrole- um emulsion containing 5*37^ water was selected* The crude was from the General Petroleum's Jones Lease at Signal Hill* It was free running black oil of approximately 24 degrees A.P. I* gravity* In some previous work in the Department of Chemistry, University of Southern California, the emulsion had been broken, the water content separated, and its per centage determined. Table I Water Oil Color — clear Color — black On evaporation considerable salts were deposited. Principal salt NaCI API Gravity 80 penetration Asphalt — 23*7 - 28% Viscosity Seybolt & 100° — 156 Observation under the microscope showed only homogenious film of each liquid. a thin It was thought advisable to use the separated water and oil in various amounts, with various emulsifying agents, 68 69 to make emulsions of known content, in order that data col lected would he more comprehensive. The method of making the emulsion was by agitation, or by passing the component parts through a colloid mill. The emulsions formed readily in all cases where the percentage of water was below 3Gj£. The water above that amount could not be dispersed,, but would separate in large drops. It is doubt ful if any of the emulsions contained more than Z6% water. Methods of Forming Emulsions. Several methods of emulsion formations were tried in making different types of emulsions. Table XT shows the relative value of these methods. Sbme of these methods are adaptable to laboratory emulsifi-* cation* but would have little value in industry. Hand shaking and mechanical rocking are two of these methods. They ares (l) batch methods, and (2) adaptable only to small quantities of liquid. Steam agitation and air agitation, while capable of industrial use, do not properly agitate the liquid to form uniformly sized globules. In addition, steam and air, if hot, tend to cause fractional vaporization of petroleum. Churning and the colloid mill are well adapted to industrial use, and both may be continuous processes. Churning, air agitation, and steam agitation, while possibly continuous, are continuous at the expense of adulteration of the formed emulsion with new material, unless the flow he controlled through check valves, 70 and the process he repeated to gain the final degree of per fection desired.. Table II Methods of Formation and Stability of Crude Petroleum Emulsions Method Size of Droplets as Seen through Microscope Uniformity of Size Stability Air agitation Large to medium Hot uniform Unstable Steam agitation Large to medium Hot uniform Unstable Hand shaking Medium to small Hot uniform Moderately stable Mechanical rocker Small Hearty uniform Moderately stable Churning Small Uniform Permanent Colloid mill Extremely small Uniform Permanent The colloid milt is especially adaptable to industry, and is of equal value in the laboratory* Its action is com plete in one operation* and the finished emulsion flows out as fast as the ingredients flow in* The principle of the colloid mill is that of a rapidly rotating vertical shaft with a flat circular head beveled to wards the upper side* The head of the machine may be adjusted 71 from a clearance of *002 inches to a clearance of over a half Inch* The head of the machine is Jacketed, so that it may he coaled or heated as desired* The high speed of rotation and narrow space, in which the emulsification takes place, produces an extremely permanent emulsion* The size of droplets depends on the type of apparatus used* It seems that greatest agitation produces the most even dispersion* Churning and the colloid mill produced the smallest droplets* Those produced with the colloid mill were visible only under a high-powered microscope* The emulsions formed In the colloid mill were by far the most stable* After weeks of standing, no separation was visible, even with emulsions containing 35# water* The emulsions were tested for viscosity, surface tension, and examined under the microscope* Photographs were taken of emulsions that showed exceptional properties, or that might be considered to represent any group* Viscosity tests were made with a Seybolt Universal Vlseosimeter at 10G°F. It was thought advisable to make vis cosity readings at temperatures which would not start a breaking of the emulsions* Three determinations were made, and the average value taken* Surface tension measurements were made with a du Fouy Tensiometer* Ten determinations were made, and the average value taken as the surface tension. Values, as determined on 72 the du Nouy apparatus* varied as much as ten tenths of a unit of measurement * and occasionally* it was necessary to disre- gard a reading. Table III Viscosity and Surface Tension Varying with the Clearance of the Colloid Mill Emulsifying Agent — None Added 25# Water 75% Oil Set of mill fine ■ § - turn 1 turn 2% turns 2 turns Viscosity 409 at 10Q°E. 270 229 240 223 Surface 34.6 tension 33.6 33.0 32.9 32.8 Emulsifying Agent — day Added 25# Water 75# Oil Set of mill fine i turn 1 turn Viscosity at 10Q°F. 292.6 312.8 318.7 Surface tension 34.0 34.4 34.5 While the proceedings far viscosity and surface tension determinations are standardized* microphotography is a process in which individual skill and judgment play an important part* The emulsions were examined under a . microscope capable of magnifying 100 and 430 times. Those emulsions that ap peared distinctive in any feature were photographed. Table IV 73 Percentage of Water and its Effect on Viscosity and Surface Tension Unulsifying Agent — Hone Added Oil and Water Colloid Mill Set as Fine as Possible % of water 1 3 5*37 10 25 50# Viscosity at 100°F. 157*2 173*0 191*8 300*0 409.0 1250*0 Surface tension 32*3 32*9 33*6 34*2 34*6 36*0 Appearance under microscope All of these emulsions appeared thin film under the microscope, were well dispersed and of even similar in the The droplets size. Emulsifying Agent — Clay Added Oil and Water Colloid Mill. Set as Fine as Possible % of water 1 3 5*37 10 25 50# Viscosity at 100°F. 203*0 202*5 211.Q 228*6 292*6 Surface tension 32.8 33.0 33*3 33*8 34*0 Appearance under microscope The films of these emulsions appeared similar. & ^ETote* It was impossible to get emulsions of 50^ water con tent to form in the machine* Taking into account the amount of free water which was not dispersed, it was estimated that this emulsion contained approximately 35^ water* 74 The microscope was a Bausch and Lamb instrument— standard for laboratory use. The camera was- a plate type camera complete with brackets for holding camera and micro scope. The process of taking the picture was that suggested by the Eastman Kodak Company in "Photomicrography**• A drop of the emulsion was placed on a slide and covered with a cover glass. The slide was then placed on the microscope table and illuminated from the under side. Both the tungsten lamp and the 4GW house globe were used. Best results were obtained when the specimen was illuminated with a 4QW globe. The intensity of the light was adjusted by moving the lamp near to or away from the microscope, adjusting the diaphragm, and by the use of filters* Filters of various colors and shades were tried until one was found to give good results. Hien the specimen was properly illuminated* it was brought into focus, and the camera lowered into a matte black cap circling the eyepiece. The camera had no lense, but was so set that the image as seen in the eyepiece would focus on the plate. As the focus of the microscope was ten inches, the camera plate was set ten inches above the eyepiece, and then adjusted for the clearest image. The image was focused on the ground glass plate, and then brought into better focus by using a hand lense and clear glass plate. The time of ex posure was dependent upon the intensity of illumination and the filter used* Best, results were gotten with use of a medium green filter*. Details were made more clear. Shading and shadows: were hrought out to give the appearance of perspective. 76 Plate 1 25# mater 75# Oil Colloid mill set fine Viscosity 469 seconds at 10C°F. Surface tension 34*4 Illuminated through B Filter Ho. 58 Magnification 1GG x l&nulsion 5 days old Plate 2 25# Water 75$ Oil 1 gram clay Colloid mill set fine Yiscosiiy 203 seconds at 10O°F. Surface tension 33*8 Illuminated through 5 Filter Wo* Magnification 100 x Emulsion 5 days old Plate 3 2bl% Water 75£ Oil Colloid mill set 2 turns Viscosity 223 seconds at IO0°F. Surface tension 33.0 Illuminated througit B Wilier Fa* 58 Magnification 100 x Emulsion 5 days old 19 Plate 4 2S|£ Btter 16f Oil Celleti& till set 2 tttng Surface tmies 55*0 at LOO0?. Hbalfiitci B inter It* SO Kfcg&ifteat Sea 430 x Bttlti«i 3ft dtsys tld Wtmt a ef folrlef II asf HI* it ess te eenclti&ed teat tits warnt germanest SBSlftiefir era ftitti fss lit greatest agitatlas isi witMif tee asalleet spaces* The eolleid mill is tbs brat igpiiBt far ftnd^g emelttiemr* 9s keep emit petreleiHe essleis&s frem ftmlsi is tit# vtil tt pipes leading It storage* tb# petreletoi prediction engineer should iliiintit, as far as passible* eoiiitiss similar t# these under ^iel tnltitni are fessi» A tti% tf Tables III sb£ XT allows «t te conclude that Tiseesity and surface teaeien as# comparable, that is* the rieceslty* the greater the serf see tansies* testing far serf see tension is stapler and a&eh quicker #eteasinet leas * the tt&tissttr should ha asire exteseisely- ess# is stewing the if esstlsiess* It is suggested that a chart he safe fta actual eieeesity sad serf see tension deteminet ions that ext# determination ae te transcribed late the ether* From tea tables and the photographs af eaaXsieas, it ess te iifiiliM that tea fitter tee SisisSas ef the dispersed phase* tee sere permanent the emulsions hence, a study ef as emulsion would indicate the stability ef the 80 l * . f t t m icroscope t B d i te tte degree fef de-emKlsifieatiG®: eeedee* A quick* accurate and eompreteiisf pet rolcum emulsions can te aecempil ished QBtd is aa tte preeeae pr©~ state of crude te tafciee* ate % eteerring tte specimen Ahraham* Herbert, *tephali rad Allied SuBstances* Alexander, •S^mposiam ef Cctlleid Chemistry** Am. Chemical Society Atetraetm* Am* lotti liilBg rad lit* S^iattnii fammamrlBta* te* Petroleum Institute, tefelieatiram• Caiifermla State Mining Bureau, Fufclieetiema« Chamot sol Hastm, *Braitete ef Chemical fer College#* American Jmtnel ef Xhd* and HllA!Ed | X* B* , BiAeal, *Sfctrface Chemistxy** Barter, C* W. * *€erfea& Ure», I*. C*, "ffttrdeui Production C. 8« Bureau ef Kite, Mtlcttim* California State 1Helms terras, Publication*'

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University of Southern California Dissertations and Theses

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Asset Metadata

Creator Slayden, H. L (author)

Core Title Tests and properties of crude petroleum emulsions

Degree Master of Science

Degree Program Chemistry

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, organic,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-786607

Unique identifier UC11348165

Identifier EP41474.pdf (filename),usctheses-c17-786607 (legacy record id)

Legacy Identifier EP41474.pdf

Dmrecord 786607

Document Type Thesis

Rights Slayden, H. L.

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA