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Dec. 20, 1938'. _ c. s. CERF ' ‘ 2,140,574 PROCESS OF DESALTING MINERAL‘ OIL , ' Filed Aug. 16, 1937 iepara/or 7) f ‘ /Z _ 5- /7 ' ‘ 6 . M'rjlera/l _ v ‘2202a, ‘ // free 0/'/ - ‘ "-9 Wafer 0/7 » ?rg- sa/f ' Pack sa/f ‘ ‘ > - m -/4 P5 Wa/er ' Wafer ’ I INVENTOR. Cad/v’; 5. Cerf‘ ATTORNEY. 2,1405%; Patented Dec. 20, 1938 UNITED STATES mrsm orrica 2,140,574 PROCESS OF DESALTING MINERAL OIL ' Cedric s. Cerf, Holt, Calif. Application August 16, 1937, Serial No. 159,222 11 Claims. This invention relates to the desalting of min eral oils. The term “mineral oil” is used herein and in the claims as referring to petroleum hy drocarbons, as ordinarily produced after the 5 petroleum has been largely separated from any attendant emulsion. This invention is not con cerned with emulsion-breaking, but with the re moval of those inorganic salts, usually sodium chloride, calcium chloride and magnesium chlo 10 ride, which gasoline manufacturers have found such a problem. For a long time the oil industry was not cognizant of the fact that in a‘day’s oper ation there would be fed into a still, along with the crude petroleum, a mass of inorganic salts 15 which could be readily measured in tons. These materials make their presence known by a high corrosion rate, by “spotting” of still bottoms, and by erosion. The mineral oil- to which attention is directed herein is therefore relatively dry, 20 emulsion-free, but contains an undesirable salt content, including chlorides. - Prior to the ?ling of this application, it ha been proposed by the Petroleum Rectifying Co. that mineral oils, of the character dealt with in '25 this application, be desalted by being contacted with water to the end that the salts be dissolved out. To remove the salts e?ectually, it was found (Cl. 196-4)‘ As I have previously explained, this invention is concerned with a salt-containing mineral. oil which is relatively dry by reason of prior treat ment or because it is so produced. I have been able to successfully reduce the salt content in mineral oils containing a small amount of water. For example, upon treatment of an emulsi?ed crude from Section 5, Kern Front, Standard Oil Company of California, I was able to reduce the S. and W. (sediment and water) content from 6% 10 to 1% and to reduce the chlorine content to nil. Referring, for example, to the operation as dia grammed in the drawing, the incoming oil was passed into the bottom of a tower 6 wherein a bed of mineral ?ooded with water was main- l5 tained. This mineral is fully disclosed in my co-pencling application Ser. No. 69,225, ?led March 16, 1936, and my co-pending application with Conrad Ser. No. 131,198 ?led March 16, 1937. The e?luent from the tower 6 was passed through 20 line 1 into a separator 8 wherein excess water was drawn off through line 9. To maintain the min erals water-?ooded, in accordance with the teach ing of my aforementioned application, water was introduced through line l0 into the base of the 25 tower, as was needed. The oil was introduced into the tower through line I l. The substantially necessary to re-emulsify the oil.‘ It appears that dry oil passing out. from the separator through the salt is held in -the oil, often being surrounded 9 line 12 was directed into the base of a tower Ill 30 by wax-like bodies which prevent water from ?lled with‘ crude rock salt. The nearly dry oil 30 gaining access to the salt and removing it by was passed upwardly through the rock salt and. solution. Thereafter, in accordance with the water was drained o? of the rock salt, as it ac Petroleum Rectifying Co. process, it was necessary cumulated, through line l6. Outlet I‘! provided 7 to break the petroleum emulsion, thereby includ ‘ for the drawing oif of substantially dry chloride86 ing the cost of‘ a de-emulsi?cation step in the _ desalting operation. It is generally the broad object of the present invention to provide for the desalting of a min ‘ eral oil while obviating emulsi?cation. 40 Another object of the present invention is to free oil. ~ I claim no novelty in the material per se of which the bed is composed but may use any water and oil insoluble solid substance. Thus, the bed 40 provide a new and novel process for desalting of may be formed of one of the minerals disclosed a mineral oil. by Robinson, (Patent 1,974,692) such asyhematite, _ A further object of the present invention is to provide a relatively simple process of low operat 45 ing cost which can be effectively used to reduce the salt content of a mineral oil to the order of 0.001%. _ ‘ . 35 My application Serial No. 69,225 ?led March 16, 1936 contains the following disclosure: hornblende or garnet, or it may be “of quartz, glass, iron ?lings, pyrites or hard burned or vit rifled clay. The surfaces of these materials af- 45 I forded by crushing the massive body and screen ing to suitable size ranges are usually the most desirable as well as the easiest to prepare, but The invention includes other objects and fea tures of advantage, some of which, together with ‘ clay products with or without the additiq'i; of 50 the foregoing, will appear hereinafter wherein oxides may be formed into pellets before or during 50 the present manner of practicing the process of burning and such shaped materials are included in references to fraginental materials. this invention will be disclosed. The physical structure of the bed proper is a The drawing accompanying and forming a part hereof is a diagrammatic representation of the matter of considerable importance. For exam--v ple, a sand bed is of such ?ne mesh that the chan- 55 process of the present invention. v 2 ' 2,140,574 _ nels between the sand grains are extremely nar row. I have found it is impossible to force any appreciable quantity of emulsion through these channels without lifting the sand and bringing it into suspension. It is also impossible to main tain a sand bed submerged with water except as to its upper surface, that is, it is impossible to keep the narrow pores between the sand grains ?lled with water and at the same time to pass ll) emulsion through them. If the water is forced‘ out, the grains become oil wet and nonfunctional for this purpose. ' I have found that a bed of the ?neness of sand can not be kept water-?lled if any considerable 15 quantity of emulsion is to be passed through it. ‘To keep the bed water-?lled and also conductive to emulsion, the channels must be wide enough to ‘permit the emulsion to pass the water inside the channels. 20 - It is true that if any emulsion is resolved in _ the bed there will be a supply of water produced by the resolution, and if the water percentage is large and' the channels are su?iciently open this supply might be enough to [keep the bed water' 25 wet. However, a relatively dry emulsion or oil will displace the water from a sand bed and cause it to become oil wet. I therefore ?ood the bed and keep it ?ooded, whether by means of the resolution water or by means of an added water 30 supply. In accordance with this invention I do not use material as fine as beach sand since that is not suitable. Instead I employ material of a size such that, when a bed thereof is ?ooded with 35 water, the integrity of the water ‘body ?lling the interstitial space is maintained. With particles the size of beach sand, this cannot be secured, oil ?lls the interstices, the ‘solid material becomes oil wet and useless. I prefer to use relatively coarse material and 40 I have successfully used material wherein the sizes were between 7/64 and 1%.; of an inch. With different materials the coarseness can be varied and I do not wish to be limited to the sizes speci ?ed since the factor governing the selection as to 45 size is to be sure that the material is always coarse enough so that the water body in the interstices is not displaced by oil and the material oil wetted. In some cases it is desirable to place a layer of relatively coarse fragments (as for example about 50 1/2 inch) on the foraminous support and to im pose on this layer successive layers of progres sively smaller fragments (as for example % inch, M; inch, 1“; inchand 5/8 inch). The ?nest ma terial should be appreciably coarser than. ordinary 55 V sand in any case, and always coarse enough to ensure maintenance of the integrity of the water in the interstices. The above gradation is sug gestive only and it is possible to make the entire bed of fragments of substantially one size,.but for reasons which will appear a bed so constructed will have a reduced throughput. Successful re sults have been secured with a bed of particles 65 of sizes between‘ 7/64 and 1%; of an inch. In order to resolve the emulsion it is passed up subjected to a'cleaning process. I therefore in troduce water, or material carrying a large per centage of water as an easily resolved emulsion, in advance, in quantity su?icient to completely submerge the mineral, and maintain this aqueous submergence at all times, both while the treat ment is in progress and during any intermission between treatments. The water liberated by the resolution of emul sion remains vin part suspended in the oil and in part joins the initial water body, which over?ows to a corresponding degree and ‘keeps the vessel ?lled with water. It is necessary to bear in mind in this connection that if the channels through the mineral body be too narrow, or if the emulsion 15 be too viscous for the width of the channels, the water liberated by resolution may remain com pletely suspended in the oil phase. In such case a gradual entrainment of the original water body may result, by which it will be in part or entirely 20 carried into the over?ow and replaced by oil, and to just that extent the bed will becomenonfunc tional. If this tendency should manifest itself there are three remedies available: (1) to reduce the ve 25 locity by lowering the throughput or by rebuilding theJ bed with larger fragments to afford wider channels; (2) to reduce the viscosity of the emul sion, as by predilution or heating; (3) to feed water continuously while feeding emulsion. 30 The choice between these alternatives for main taining the integrity of the water body will de pend on several conditions. First, resolution is usually accelerated by heating, and to such de gree that it is economical and pro?table to heat all except'the lightest emulsions. It is therefore usually the case that all the heat which the emul sion will tolerate is already being applied, so that a further heating effect is not available. The maximum permissible temperature is in all cases below the boiling point of water and, unless a condensing system is provided, is below the tem perature at which appreciable vaporization losses are incurred. . ' Resolution is also accelerated by increase in the velocity of emulsion ?ow- through the chans 45 nels between the fragments, the limit to this in crease being the point where turbulence sets in and tends to produce reemulsi?cation. The ac celeration of resolution with increasing velocity follows from the nature of the treatment, the effect of resolution being produced by the‘ actual contact of the dispersed water particles with the water-wet solid surfaces. These particles, dis persed and suspended in the oil phase, arebrought into such contact by their inertia, which causes them to move in straight lines out of the narrow streams of oil asthese streams are de?ected from straight lines in passing through tortuous chan nels. Such an inertia effect is afunction of ve locity and while no numerical limits can be set, because of the extreme diversity in particle size, gravity difference and ?uid friction, it will be found with any given emulsion that the rate of resolution at very low velocities is extremely 65 small, that the rate increases rapidly- as the ve the emulsion stream is introduced the vessel ' locity increases, and that resolution ceases when should be ?lled with water to a level su?iciently the velocity of turbulence is reached. high to cover the mineral. It is not sui?cient to Widening the channels by the use of larger 70 merely wet the material with water as the oil fragments reduces velocity for any given through phase of many emulsions will displace a water put rate and therefore reduces the tendency to 70 ?lm if allowed to remain in contact with it, the ward entrainment of water. However, it also re effect of mass action reversing the normal selec duces the rate of resolution and is equivalent to tivity of the solid surface. Once oil wet, the solid or requires a reduction of throughput. This is surface is thereafter inactive until it has been 75 intrinsically undesirable although in some cases it 75 wardly through this fragmental bed, but before , . 2,140,574. 3 flow that ordinarily a petroleum emulsion would is useful to reduce ebullition of gas from oils hav This objection does re-form. However, because of the presence of not apply to the step of feeding water along with the water-?ooded mineral, emulsion formation the emulsion, as only such supply is required as does not occur and instead the oil is so agitated ing a high vapor pressure. and contacted with the water, scrubbed with the will balance the usually slow rate of entrainment, and the addition of this‘small proportion of water will usually be found to increase rather than to diminish the rate of resolution, due to the increase in velocity. water, that sodium chloride and other water- . soluble salts therein are effectively eliminated, particularly the chloride content. It may be said that the addition of ' ter. 1 I have successfully operated the mineral bed with water from which chlorides have been water will seldom be required if the emulsion un der treatment contains a large proportion of wa eliminated, and also with aconcentrated brine. ‘ The action in this respect is hard to explain, The purpose served in using progressively smaller fragments in the upper layers of the min 15 eral bed is to increase the velocity asthe emulsion is progressively resolved. Resolution consists es_ sentially in agglomerating ?ne water particles into larger drops, and as this e?ect progresses the number of particles suspended in the oil phase becomes smaller and their spacing greater, re quiring an increased inertia effect to bring a unit number of particles into contact with the solid surfaces. The same effect may be produced, though in a less desirable manner, by progresi 25 sively decreasing the cross sectional area of the bed in the direction of flow, thus accelerating the flow of the emulsion stream as a whole. In no case should the channels through the because I have secured successful results with both treatments. Possibly different explanations apply in each instance. While the preferred process is that disclosed, i. e., using both the water-?ooded mineral bed and the rock salt column, either can be used, and I have‘ success fully desalted oils using the water-?ooded min eral bed and utilizing the rock salt tower sep 20 arately. In place of rock salt, any other inor ganic material of a water-soluble and highly ionizable nature can be employed. I claim: 1. A process for desalting a substantially dry 25 emulsion free mineral ‘oil comprising passing‘ said substantially dry emulsion free oil upwardly through a stationary bed of rock salt while main , bed be narrow enough or the velocity of ‘the liquid taining said bed dry. 2. A process for desaltinga substantially dry 30 high enough to cause the mineral to be lifted from emulsion free mineral oil containing only about its position or brought into any degree of suspen 1% of water comprising passing said oil in the sion to any substantial extent. In order to pro duce the desired effect of resolution without loss presence of only said 1% of water upwardly of mineral agent and without oil wetting the agent through a stationary bed of rock salt and~draining separated water off said bed. 35 35 the mineral bed should be ?xed and permanent 3. A process for desalting a substantially dry in position. As was previously stated, the S. and W. content emulsion free mineral oil comprising passing said substantially dry emulsion free oil upwardly of the incoming mineral oil was 6%. That pass ing out through line I‘! carried only 1%. The through a substantially dry stationary mass of salt crystals, and draining separated water off 40 40 incoming oil contained 0.04% of ash but this was reduced in the oil passing out through line I‘! adjacent the bottom of said mass. to 0.026%. The oil passing through line l2 con 4. A process for desalting a mineral 011 com tained only 3% S. and W. while the ash content prising passing said oil through a mineral bed‘ had been reduced to 0.033%. The treatment in maintained ?ooded with water, separating out only the mineral bed was effective to reduce the free water to provide dry emulsion free oil and 45 chlorine content to zero, but an appreciable cal then passing the dry emulsion free oil through i cium and sodium oxide content still remained in a substantially dry mass of‘ salt crystals. the oil, amounting to 12.5% on the basis of ash. ' 5. A process for desalting a mineral oil com Passage through the rock salt reduced the sodium prising contacting the oil with water under con oxide content to zero. ditions normally tending to emulsion formation 50 In a similar operation, treating a crude oil for ' but in the presence of a material effective to re 50 the Lion Oil Company of Arkansas, the oil in its solve an emulsionof said oil and water, and sep arating the oil from said water to provide sub “wet” condition contained0.0097% sodium chlo ride. The oil passing through line 12 had a salt stantially dry emulsion free oil and passing the content of 0.00594%, while that passing out of so water-treated substantially dry emulsion free 55 line H was reduced to 0.001451%. The other salts oil through a dry salt bed. _ present of a deleterious nature were similarly re duced. I have also been able to successfully desalt the oils utilizing rock salt alone, and upon the afore mentioned oil from the Lion Oil Company the same wet oil was introduced through line l2, with out previous treatment by the mineral. Passage through the rock salt bed alone reduced the salt content to 0.00105% and the other salts were like wise reduced. , The treatment accorded the oil in the water ?ooded mineral bed, I have determined upon study in glass, is such that although normally one would expect an emulsion to re-form, such is not apparently the case because of the presence of the mineral which, as I explain in my co-pending application, is effective to resolve a petroleum emulsion. Therefore, I can successfully contact 75 the dry oil with water under such conditions of 6. A process for desalting a mineral oil com prising contacting the oil with water carrying a relatively high salt concentration under con ditions normally tending to emulsion formation 60 but in the presence of a material effective to re solve an emulsion of said oil and water, and sep arating the oil from said water to provide sub stantially dry emulsion free oil and passing the so water-treated substantially dry emulsion free 65 oilthrough a dry salt bed. 7. A process for reducing the salt content of a substantially dry emulsion free mineral oil to the order of 0.001% comprising contacting said oil containing an undesirably high-salt content 70 with a relatively dry mass of an inorganic water soluble highly ionizable material e. g. sodium chloride, removing said oil from the material and separating from said material any water liberated from said oil. 75 4 25,140,574 8. A process for reducing the salt content of a substantially dry emulsion free mineral oil .to the order of 0.001% comprising contacting said oil containing an undesirably high salt content with a relatively dry mass of an inorganic water soluble highly ionizable material e. g. sodium chloride. _ 9. A process for desalting mineral oil compris ing passing substantially water- and emulsion oil through a substantially dry rocl: salt mass, and maintaining said rock salt mass substantia1— ly-dry. 11. A method 'of treating an'oil-water' emul- ‘ sion to rid the oil of emulsion'and salt compris ing a treating the emulsion by passing-said emul sion upwardly at a velocity belowthat of turbu lent flow through a porous bed of fragmental, solid, insoluble material in which the fragments 10 ‘free mineral oil through a substantially dry mass ' are so large that the integrity of a Water body 10 of rock salt. ?lling the interstitial space in said bed is main- ‘ 10. .A method of treating an oil-water emulsion to rid the oil of emulsion and salt comprising treating the emulsion by passing said emulsion tainable,v the fragments comprising said beds in cluding those of a size between %4 and 1%‘; of an inch, continuously maintaining interstitial ’ 15 upwardly through 'a porous bed of fragm'ental,” space in said bed substantially ?lled with water 15 solid, insoluble material in which the fragments are so large that the integrity of a water body ?lling the interstitial space in said bed is main tainable, continuously maintaining interstitial 20 space in said bed substantially ?lled with water and the bed water flooded, permitting the so treated emulsion to ‘stand and separating o? water to provide substantially dry emulsion-free ‘ oil, passing said substantially dry emulsion-free and the bed water flooded, permitting the so treated emulsion to stand and separating off water to provide substantially dry emulsion-‘free oil, passing said substantially dry emulsion-free oil through a ‘substantially dry rock salt mass, 20 and maintaining said rock salt'mass substantial 1y dry. CEDRIC S. CERF.