Патент USA US2119759код для вставки
«Tune 7, 1938» . K. |_. WALLIN » 2,119,159 SEPARATION oF wAx Filed oct. 29, 1955 2g, T4 SUZYQZZÍM v à25 ‘ @der IN VEN TOR. Kenne-fh L. Wal/fn ATTORNEY. ` _2,119,75el Patented June 7, 1938 , UNITED STATES> PATENT oFFlcE SEPARATION ' 0F WAXV > Kenneth L. Wallin, san Pedro, Calif., assigner to Union Oil Company of California, Los - Angeles, Calif., a corporation of California Application October 29, 1935, -Serial No. 47,276 7 Claims. This invention relates to a process for separa tion of Wax from a mixture thereof With asphal tic and resinous materials. More. specifically, it relates to a process for separating a mixture of Wax and asphaltic and/or resinous'materials from an oil containing same, and then separating and resolving the thus obtained mixture into sepa rate fractions' of Wax and of asphaltic and/or resinous materials. Asphalt may be separated from oil either by distillation or solvent extraction. By the ordi nary distillation methods, the oil, being more volatile than the asphalt, is Vaporized, and may then be condensed and recovered as a distillate, while the asphalt, which is substantially non volatile at the temperatures required to vaporize (Cl. 19d-20) , Wax and asphalt containing oil with asolventA at such a temperature that only the oil is dissolved therein, the mixture of Wax and asphalt> being recovered as the undissolved precipitate. The further separation of the thus obtained mixture 5 y' into the wax and asphalt components involves diiñculties. Thus, an ordinary asphalt-Wax mix ture obtained as a precipitate from >a solvent ex traction of an oil containing Wax and asphaltic materials may be heatedk to a temperature' above the .melting point of Wax without any separation of an asphaltic phase. One of the' known methods of resolving ’asphalt Wax mixtures consists in commingling the as phalt-wax mixture atl atmospheric orV elevated 10,; temperatures with a light hydrocarbon solvent, the oil, remains in the still and is recovered as a such as liquefied propane. The solvent dissolves residue. If wax is present in the oil being de ~ the Wax from the asphalt, the Wax- being Vthen asphaltized, the Wax is partially distilled over recovered from the'hydrocarbon solvent solution head in the medium and> heavy overhead dis tillate fractions. A complete separation of the remaining Wax from the asphaltic residue cannot be obtained by any ordinary distillation means owing to the high boiling point of certain of the parai’ñn or Wax members p-resent. If a further separation of the Wax from the overhead dis tillate is-desired, this must be accomplished by processes such as cold settling, cold pressing or centrifuging Which are Well known to those skilled in the art. v by distillation ofthe solvent >or by refrigeration of the solution to precipitate the Wax. However, in the operation of this process, vsome of the as phalt still remains dissolved in the solventsolu tion along with the wax, and'comesI out together with the Wax upon distillation or refrigeration. It is, therefore, an object of the present inven tion to provide a method which would obviate the above diñ‘lculties and Which would lresolve such asphalt-Wax mixtures more easily and economi 30 It has now been discovered that the relatively ration of oil and asphaltic materials, itis possi small amounts of oil still remaining in an as' ble to use solvents in Which the oil is relatively phalt-Wax mixture obtained from a solvent eX soluble but in Which the asphaltic materials are traction of an oil containing said substances, pre E relatively insoluble. Thus, when naphtha, gaso vent an easy resolution of the mixture into its 35 line or even the lighter hydrocarbons, such as constituent fractions. It was further discovered liquid ethane, propane or butane, are employed ' that these relatively small amounts of oil act as a as selective solvents to separate the asphaltic mutual solvent for both the Wax and *the as cally. ' ' ‘ In employing solvent extraction for the sepa materials from the oil, the former being substan phaltic materials, >thus maintainingthem -in the 5 tially insoluble in the foregoing solvents, are left ' form ofv a homogeneous mixture above the melt as a residue While the oil is separated from this ing point of the Wax.v It was still further dis insoluble residue as a solution of oil in the sol covered that the miscibility of the Wax and ofthe vent. The term “solvent extraction”,.as used , asphaltv materials decrease With- a decrease in the hereinbelow, is intended to include the above amount of oil remaining in such, `asphalt-Wax 5 type of asphalt precipitating solvents. mixture. Thus, an asphalt-Wax mixturey as re 45, Where Wax is present in the oil containing as moved irom a solvent Yextraction. of an oil con phaltic materials, the Wax may be separated taining same may be heated above the melting along with the solvent and oil by maintaining the point of the Wax Without any phase separation, solvent at a temperature at Which the Wax is While the same mixture, after a substantial de j dissolved in the solvent Vtogether >with the oil. oiling Will deposit the asphaltic substances as a The wax may then be removed from the asphalt bottom layer when the mixture is heated to or free solution by chilling the solution and then somewhat above the melting point of the wax. separating the precipitated wax by settling, filter The -term “asphalt-Wax mixture”, as' used in ing or centrifuging. f f . ' ' Another method consists in commingling the the present specification and claims, includes mixtures of these substances as obtained from ne 2 2,119,759 solvent extraction of an oil by filtration, cen trifuging or ordinary precipitation. These mix tures may be in a liquid, semi-solid or solid state. Therefore, broadly stated, the invention re sides in a method for resolving an asphalt-wax mixture, as obtained from a solvent~ extraction of an oil containing same, or from any other similar source or operation, which comprises sub stantially de-oiling said mixture and subsequent ly raising the temperature of the thus de-oiled mixture to the melting point of the wax. The invention further resides in a method for resolving an asphalt-wax mixture, as obtained :from a solvent extraction or dewaxing of an oil containing same, which comprises commingling the asphalt-Wax mixture with new quantities of a solvent under such condition that substantially all of the oil still remaining in said mixture isdissolved in said solvent, removing the oil-solvent 20 mixture from the asphalt-wax mixture, and sub sequently raising the temperature of the thus substantially de-oiled asphalt-wax mixture to or above the melting point of the wax, thus causing the asphalt to precipitate from the liqueñed wax. The above de-oiling step may be carried out by cold leaching of the asphalt-wax mixture or by dissolving the wax in a solvent followed by a recrystallization by refrigeration. As an example of the realization of the process 3.0. constituting the object of the present invention, a mixture of oil, asphalt and wax, having a gravity of 28.7° A. P. I. at 60° F. and a melting point of 115° F. was leachedv twice in propane at- _40° F., the ratio of propane to mixture being each time 3 to 1. After filtration and the depropanizing of both the filtrate and the residual mixture, the filtrate, which constituted 40% of the original mixture treated, had a 21.0° A. P. I. gravity and a. 0f’ F. pour point. The residual mass consisting of wax, asphalt and some oil still dissolved there in had al gravity of 34.3° A. P. I. at 60° F. and a melting point of 125° F. It is obvious that there is an optimum tempera ture for the separation of asphalt from the de oiled wax, this optimum temperature depending on the character, viscosity, solvent power, etc. of the wax. This temperature, however, must be sufticient to reduce the viscosity of the wax to a point at which the asphalt may readily settle out. On the other hand it must be maintained suf fìciently low to avoid dissolving of the more soluble portions ofthe asphalt in the thus lique 10 fied wax. The separation of the asphalt from the deoiled wax-asphalt mixture may be carried out by a simple sedimentation and decantation operation. However, filtration may be resorted to for the 15 purpose of removing the asphalt from the melt -ed wax. Obviously, the combination of the two methods is also applicable. For a better understanding of the present invention reference is made to the accompanying 20 drawing which discloses one form of a flow dia gram which may be employed for the realization of the present invention. Referring to the draw ing the oil containing wax and asphalt, is con veyed through line II) into the iirst leaching tower II wherein it is leached, as for example, at a temperature of -40° F. with a lcooled solvent such as propane introduced through line I2. The oil-solvent mixture is removed from said leaching tower through line I3 while the wax-asphalt 3,0 mixture still containing oil is conveyed through line I5 to the second leaching tower I'I. Here again, this wax-asphalt mixture contain ing oil is leached with further quantities of cooled solvent being introduced into said tower I1 through line I8. The solvent with the oil dis solved therein is removed from said tower through line I9. The residual mass, consisting of wax asphalt and some oil still dissolved therein is then removed from tower I'I through line 2| wherein it is comrningled with optimum quanti Although containing ties of a solvent such as propane introduced both asphalt and wax, it was impossible to sepa rate them from each other, presumably due to the through line 22. The mixture is then heated at relatively high content of oil still present therein. 23 to a temperature at which the wax and asphalt become dissolved in the solvent, so that the mass The wax-asphalt mixture, leached as described above, was. then recrystallized from propane and ñltered at 0° F. This. operation was carried out three timesV at the end of which the washedY wax conveyed then through line 25 into the crystal lizer 26 is homogeneous. This crystallizer is cooled- as by means of a cooler 2l, the temperature being such as to cause recrystallization of the asphalt mixture constituted 48.6% by Weight of wax-asphalt mixture. The solvent and oil are re the original substance treated, had a gravity of 39.0° A. P. I. at 60° F. and a melting point of 133° F. 'I'his wax-asphalt mixture had only 3.4% of oil still remaining therein as shown by an acetone-benzene method of testing. On heat ing the thus deoiled Wax-asphalt mixture to a temperature at or above the melting point of the wax, substantially all of the asphalt in the mix ture settled out of the molten wax, and it was found that the asphalt remained insoluble even when the temperature'Was-raised up to 300° F. It is to be noted that the wax-asphalt mixture, moved from the crystallizer 26 through line 28 while prior to. the iinal deoiling by recrystallization from propane, still contained about 12% by 65 Weight of oil- Although applicant does not con sider himself to be limited by any theory of the case, it is his opinion that the presence of this oilv in the asphalt-wax mixture prevents the separation of the mixture into its component parts, and that the removal of the larger propor tion of the oil still remaining in the leached wax permits the precipitation of the asphalt when the temperature of the iinal mixture is raised sub stantially to or above the melting point of the` wax. , .i the‘lwax-asphaltmixtureiswithdrawnthroughline 29. The wax-asphalt mixture thus removed from the crystallizer 26 is then conveyed to a heater 30 in which the deoiled mixture is heated to a tem 55 perature at or above point of the wax, but below the melting point of the asphalt. This heated mixture is then conveyed through line 32 into separator 33 from >which the molten wax is removed through line 34, while the solid asphalt particles'precipitating to the bottom of sepa rator 33 are Withdrawn through line 35. ‘ Although the invention has been described in connection with the separation into its constituent parts of an asphalt-Wax mixture obtained from a solvent extractionl ordewaxing of an oil contain ing these constituents, it is also possible to employ` thesame method to separate the asphalt or simi lar substances which have been added to an oil containing only Wax. Thus, it is well known that 'Il asphaltic materials are used as dewaxing aids in the treatment’of waxy oils with solvents. In such casesA the asphalticY substances help to coagulate the particles of wax precipitated outV of solution, thus aiding in the subsequent separation of the 2,119,759 Wax by any of the Well-known processes. Ob viously, the resultant precipitate, when removed from the filtrate, contains both the wax and the thus added asphaltic materials. This mixture can also be separated into its component parts by the above method of de-oiling and subsequent lique faction of the wax. The above disclosure particularly referred to the separation of wax from mixtures thereof with 10 asphaltic substances, It is to be understood, how ever, that it is equally applicable to the removal of wax from- mixtures containing resinous substances or resinous and asphaltic substances. The present invention is not limited by any 15 theory of operation, nor any details which have been given merely for purpose of illustration, but is limited only and by the following claims which cover the novelties inherent in the invention. I claim: l. In a process for resolving an asphalt-Wax mixture obtained from an oil containing same and still containing residual oil dissolved in said mixture, the steps of removing substantially all of the residual oil from said asphalt-wax mix ture, and raising the temperature of the thus de-oiled mixture to liquefy the wax th’êreby per mitting the asphalt to precipitate therefrom. 2. In a process according to claim i, wherein the de-oiled asphalt-wax mixture is heated to- a temperature above the melting point of the wax but below the melting point of the asphalt, Where by the solid asphalt may precipitate from the thus liqueñed wax. 3. A process for resolving an asphalt-wax mix ture obtained from an oil containing same, said mixture still containing residual oil dissolved therein, which comprises treating said oil-con taining asphalt-wax mixture with a solvent hav ing preferential solubility for oil under conditions whereby substantially all of said residual oil is re moved from said asphalt-Wax mixture, separating the thus de-oiled asphalt-Wax mixture from the solvent and the thus removed residual oil, heat ing the thus de-oiled asphalt-Wax mixture to a 3 temperature at which the wax is liquefied, but the asphalt remains in a solid state, and remov- ' ing the solid asphalt from the thus liqueñed wax. 4. A process for resolving an asphalt-wax mix ture obtained from an oil containing same, said 5 mixture still containing residual oil dissolved therein, which comprises treating said oil-con taining asphalt-wax mixture with propane under conditions whereby substantially all of saidre sidual oil is removed from said asphalt-wax mix 10 ture, separating the thus de-oiled asphalt-Wax mixture from the propane and the thus removed residual oil, heating the thus de-oiled asphalt Wax mixture to a temperature at which- the Wax is liquefied, but the asphalt remains in a solid 15 state, and removing the solid asphalt from the thus liquefied Wax. 5. A process for resolving an asphalt, wax andv oil mixture in which the oil content is approx imately equal to the combined asphalt and Wax 20 content which comprises the steps of ñrst remov ing substantially all of the oil contained in said mixture and subsequently raising the tempera ture of the thus de-oiled mixture to cause the asphalt to precipitate therefrom and separating 26' the precipitated asphalt from the Wax. 6. A process for resolving an asphalt, wax and oil mixture in which the oil content is approx imately equal to the combined asphalt and Wax content which comprises the Steps of first re 30 moving oil from. said mixture to produce an as phalt-wax mixture containing approximately 3.4% by Weight of soil and subsequently raising the temperature of the thus de-oiled mixture’to cause the asphalt to precipitate therefrom and 35 removing the precipitated asphalt from the Wax. '7. A process as in claim 5 in which the asphalt, wax and oil mixture is de-oiled by means of a solvent employed under conditions whereby sub stantially all of the oil contained in said mixture is dissolved in the solventV and the oil-solvent solution is removed from the asphalt-Wax mix ture. KENNETH L. WALLIN.