US2380078A - Method of separating wax - Google Patents

Description

July 10, 1945. A H, HU TE 2,380,078

METHOD OF SEPARATING WAX Filed April 9, 1945 INVENTOR 4149145; fieizry 807ml? BY 3.5a 5.5 AGENT Patented July 10, 1945 iSTAT S.

PATENT oFFIc This invention 'relates to improvements in the methodof obtaining particular melting point waxes and similar "normally solid crystalline masses from a charge of such" materials with othermaterials of 8, difierent melting point, and more particularly relates to theseparation by differences in freezing point rather than frac-- tionation by differences in boiling points of various mixtures of materials.-

As is pointedout in my prior patent, No. 2,168,142,1f have found it entirely satisfactory to separate difierentmelting point waxes from a slack wax or a crude scale wax by a new method which isoharacterized more particularly by the formation of an emulsion or intimate dispersion of a waxy mixture in nonsolvent, immiscible gaseous and liquid materials such as air and water. It appears that such emulsion or agitation tends to reduce theviscosity of the lower'melting point materials such as the oils, and to form a fine dispersion of thehigher melting point materials in an air environment which tends to give an unexpected release of the liquid portion from the solid portion. It is thus possible for the first time to obtain a commercial separation of materials ofrelatively close melting and freezing points and which are normally partially soluble in one anothersuch as the hydrocarbon waxes.

It is necessary however, in the commercial production of specification waxes, which-are referred to herein as normally solid materials, by

separation of the foots oil, which isnormally liquidQto meet other requirements besides oil content, such as the tensile strength, and for this reason it may be necessary to blend waxes A further object of my invention is to provide an improved method of obtaining sharp fractionation of different melting point materialsby differences .of their freezingpoint and'in which the differences in'melting point may be as'low as one or two degrees. g

Astill further object of my invention is to improve 'thecontrol of the separation of different melting point waxes from waxy hydrocarbon fractions and mixtures thereof.

1 Further objects and advantages of my inven- =tion1will= appear from the following description persion or emulsion. the amount .of -oil .removed from the. cake will of apreferred form of embodiment thereof, takenin connection with the attached drawing illustrative thereof and in which the-figure is a diagrammatic flow diagram of the apparatus by which my invention may be carried out. In'accordance with the preferred form of embodiment of my invention, a charge material of a mixture of diiferent'meltingpoint materials such as oil and wax in the tank [0 is liquefied as byheatingandthe liquid mixture is withdrawn through theline l I.- An inert gas such as air is 1 fedinto the mixture through line I2, and a nonsolvent and normally immiscible liquid such as water is also introduced to the charge through the line l4.'"-The mixture is then agitated in a suitable emulsifying, homogenizing or other mixingdevicelG.

The mixing device I6 is adapted to disperse thehigher melting point material in the :liquid materials, and by recycling a portion through line 18 andiby the combined effect of the cooling accomplished: by the water, a material. of the character of shaving lather is discharged through line 20 against 'the pressure of relief valve 22. The characteristic of this so-called dispersion or: emulsion i rather unique in that it appears to be a plastic mass having a large number of air channels, the air of which appears to surround and perhaps to be adsorbed by the crystallized and precipitated higher melting point materials. These air channels serve as the'passages for the liquid which is evidently an emulsion of water and oil. While I do not desire to be limited to any theoryof operation, it is clear that the socalled aerogel of wax and emulsion of oil and watertends to form a mixture in which the oil is-much freer to leave the wax, and the wax becomes a highly dispersed structure so that the emulsion or dispersion may be readily separated by suitable liquid-solid separating means.

. More-particularly, I prefer to separate .this

material in a form of centrifugal eparator generally indicated at 23, which may be provided with a rotating basket 24 having a perforated side wall 25, through which the liquid materials are discharged by" the centrifugal force. The cake formed is highly porous and light and may be washed with water'or other displacing or solventagents. I have found that the cake will continuously discharge over the upper lip 26 of the separator, which is apparently due to thedisplacement of the relatively light, porous cake by the relatively heavy and dense liquid-solid dis- It will be apparent that reduce its density, and the cake does not tend to collapse but to move upward at a satisfactory rate.

The filtrate may be collected in the chamber 21 and drawn off through the line 28 into the filtrate tank 30, and the cake is conveniently discharged through line 3| to a cake tank 32.

The melting point of the cake is a function of the melting point of the mixture and a function of the o zzeratihgv temperatures. The. nearer the charge temperature is to the higher melting point material, the less precipitation of the higher melting point materials and the less yield, of higher melting point material there will be. The yield of higher melting point. material. will be nearer one melting point. however. I have now found it possible by continuously recycling all of the filtrate 30 through the lines and 31 back to the charge line i l to obtain a separation of cakes of different melting points which may be. discharged throu h lin 35. nto the separate. a ks 35a, 35th, 35 3.5 1, 35.6, etc... In. this. manner, allof the diiierent, melting, point. materials can be. segregated with any de ired degree of ac,

curacy. I

One. manner. of controlling the. temperature is y the use of a. temperature. contro le 3 interconnected in the. coolin Water l ne 14.. Such controller may be. set. to. give. periodic tem erature reductions on the emulsion. charge. t he: separater 23. If the. temp rature reduced, it. will be apparent. that; there will be a. reater am unt. of cake. but; the cake will be. of: a gr at r range of meltin oints. Br slowly reduoins; th te m perature and discharg n the ditlerent me in point cake into. the difierentcake 3%. 35% etc., as great a number of meltin point prod;- ucts. as. desired can be obtained.

The amount. of material. for each will. of course. epend. to a certain extenten. the. amount of, material; of.- the difierent melting-r points in the original charge. It will. be. apparent. howev that y adjust-ins: the temperature: throu h controller 38v and thus continuously reducing the temperature of the charge, any desired. number of fractions; of closely controlling meltin point range will be produced. The. lower temperature filtrate at each reduction in feed; t nm raturc will also. aid to reduce the. temperature of; the. emulsion feed.

It. isv possible toobtain a. specification product by the. desired blending;- of the different. meltini point.- materials. The. hi h deg-rec. of separation of oil accomplished by process provides such dry wax as. to make the further sweating:

cult, if not. impossible. It,is-,.theretotetdesimble to. provide this blendingof waxes which. cannot be. sweated to. obtain the. desired. specification material.

In one case, for example, an average. melting point cake, of 1,35? and having; a; broad wa cut varying; from; 1229' E; to 1.47; F. 'waaintroduced as feedand thetemperatureoi: the. harze was adjusted to. produce a wax; or 113.6?- There.- after the temperature: of the. operation was con.- tinued until i6 difierent. fractions. were obtained varying from 131.9 F;. to. L37."- E'.

The recycle; of filtrate. alsomakes it possible. to more carefully control the quality. oi the emulsion if, due to the amount of. solids. present; it

would be too. stifiz when the amount; ofr. solids comprises approximately 60%. of the charge, Lfhr example, cavitation frequently occurs; This an.- pears tov be due to. the fact. thatinstead. 0i. crete wax particles which can. peas tlu'ollflh the emulsifying mechanism 16 as a slurry in the oil and the emulsifying agent, a system may be obtained in which the wax crystals are macerated and mashed back into the oil by mechanical action of the mixer. A control of the recycle will, of course, prevent the so-called cavitation in the pump and will materially increase its volumetric capacity. This thus permits the use of the simplified rotary type mixer.

Alternatively it may, be. desirable to recycle some of the cake as through. the line 11 if the amount of solids in the feed is so small as to prevent the formation of the desired emulsion.

While I have shown and described a preferred form of embodiment of my invention, I am aware that. modifications may be made thereto, and I, therefore, desire a broad interpretation of my invention within the scope and spirit of my invention. and. of the claims appended hereinafter.

I claim:

1. In a continuous wax separation process ineluding. the continuo s f ming; of. n mul ion t different melting point. waxes, a chilling non.- solven-t liquid and, aninert. gas; the steps for obtaining diflerent melting point wax; fractions from said. emulsion... comprising; subieoting the emulsion progressivelytoa. continuous. liquidsolidseparating. operation to, separate a solidified higher melting point one of said waxesv from the liqu d oi the mul i n. continu usly and r pe edly re ycling; through said. separation step: an said emulsiiying step the. liquid including, lower melting point waxes. in a liquid condition senor r t d from said. solidified wax,. progressively in.- treducing chillingnonrsolvent liquid. directly to said recycled liquid in. the courses of recyc n of the latter to.- reducethe. temperatureoi the re.- eycled liquid step-by ep and solid fy! he diner nt me i g po nt w xes. in succession. Successive.- ly r ng... insaid s parating: st in. he sosolidified. wax s. from the remaining. liquid ndero ng. said.- re y ing... and segregating fromeach other the. difierentmeltine point. wax fractionaso obtained.

2.. In, a continuous; wax. separation process. in.- e uding; the. continuou i rmina, of an emulsion of difierent. mel ing, point waxea, a Chilling; non.- solvent. liquid and an inert gas; the steps. for obtaining different melting point waxfractions from said. emul ion. eomprisingsubiectine, the emulsion pro ressively to a continuous; liquid;- solid scpara ime op rati n to sepa ate asolidified hi her melting; point. one oi said waxes. trom, the liq id of the. emul ion. continuously and repeat.- edly recycling thro gh S id separation. step and 34.61: emulsifyin step the. liquid includingflower melting point waxes in. a liquid; conditio s a, rated from said. solidified wax. progressiveiy'introducing to said. emulsifiying; step additional quantities. of. said. chilling: non-solvent li uidi and ulsi y ng. the recycled liquid. therewith, regulating. aid introduction. of chilling. liq W duce the temperature of the recycled liquid-item byep and olidifu the. differentmelting} point waxes, insuccession, s ccessivelyseparating in said separating step,, the sci-solidified waxes tromthe remaining, liquid undergo ng aid re.- cycline, and segregat ng. firom. each. other the different melting point wax frantionsso-obtainod.

3., In. a. continuous. wax. separation processineludin he continuous. forming oi anmulsion of. different. melting point waxes. a. chilling; imsolvent quid nd an: in rt. gas; the steps. for ob aining; different, melting: point wax: n'mtlons from saidemnlsi'on cnmmisina; subjecting: the

emulsion progressively to a continuous liquidsolid separating operation to separate a solidified higher melting point one of said waxes from the liquid of the emulsion, continuously and repeatedly recycling through said separation step and said emulsifying step the liquid including lower melting point waxes in a liquid condition separated from the solidified wax, progressively introducing additional chilling non-solvent liquid to said recycled liquid in the course of recycling l0 the latter and emulsifying the recycled liquid with said adde'd chilling liquid to reduce the temperature of the recycled liquid step-by-step and solidify-the difierent melting point waxes in succession, successively separating, in said separation step, the so-solidified waxes from the remaining liquid undergoing said recycling, and segregating from each other the different melting point wax fractions so obtained.

AUGUST HENRY SCHU'I'IE.

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