US2674564A

US2674564A - Method for separating waxy and oily materials

Info

Publication number: US2674564A
Application number: US251109A
Authority: US
Inventors: Donald A Hermanson
Original assignee: Socony Vacuum Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1951-10-12
Filing date: 1951-10-12
Publication date: 1954-04-06
Anticipated expiration: 1971-04-06

Description

April 6, 1954 D. A. HERMANsoN 2,674,564

METHOD FOR SEPARATING WAXY AND OILY MATERIALS Filed 0G12. 12, 1951 2 Sheets-Sheet l April 6, 1954 D. A. HERMANsoN METHOD FOR SEPARATING WAXY AND OILY MATERIALS Filed OCT.. l2, .1951

2 Sheets-Sheet. 2

INVENTOR. 17am/IE f/erffmfzsa BY Qa a.

L #l OR/VEY Patented Apr. 6, 1954 METHOD FOR SEPARATING AND OILY MATERIALS Donald A. Hermanson, r1aini1,N. J.,

assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York` Application october 12, 1951, serial No. 251,109

This application is a continuation-impart. of my application Serial Number 32,017, filed in the United States Patent Oflice June 9, 1948.

This invention relates to a process for the separation of wax and-oily constituents present in a wax bearing hydrocarbon stock and more particularly to a process for deoiling waxy petroleum fractions such as slack wax and the like.

The present process is broadly applicable to the problem of separating wax and/or petrolaturn and the like from hydrocarbon oils in substantially oil free form. The present process is particularly directedv to the deoiling of crystalizable wax present in highwaxystocks such as in slack wax. y 1

A process commonly employed heretofore for thedeoiling of wax is the well known sweating process wherein the slack wax is chilled in-.pans to cause congealing of the wax after which the mass is slowly heated to effect sweating out of the liquid oil. The efciency of this process is low as compared with other methods from the standpoint of wax yields. Moreover, the process is conducted batchwise and requires a considerable length of time and delicate temperature control during the heating period.

Another process employed is the solvent deoiling process in which the slack waxis mixed with a suitable solvent such as propane or benzolacetone, for example, and then chilled and ltered. l

Still another process currently employed is the emulsion deoiling process in which the slack wax is mixed with a non viscous non-solvent while in molten state after which it is cooled to congeal the wax. Then the congealed wax is separated from the oil in non-solvent emulsion by means of a basket type centrifuge lined with a lter material. Such processes involve extensive wax recycle to provide satisfactory yields of wax with low oil content.

It has also been customary in the Vprior lart to employ iilter aids such as diatomaceous earth in powdered form to act 'as-an aid inthe dewaxing of oils by the filtration of the wax from the liquid oil. In such a process the liquid oil from which most of the wax has been crystallized is withdrawn free'of the filter aid and the waxy material. The process has not been found practicable as a method-of deoiling-waxes to obtain oil free wax. As a matter of fact, the waxy material left behind with the filter aid is generally known as slack wax and contains substantial amounts of oil. -f wIrrUnited States Patent 1,278,023, dated Sep-- 11 cleans. (c1. maiis) tember'3, 1918, there is disclosed a process for dewaxing of oils wherein the waxy oil stock is wholly absorbed by a solid porous material such as fullers earth after which the fullers earth is chilled to effect congealing of the sorbed wax. The fullers earth is then treated with a suitable oil solvent whereby the liquid oil is removed leaving behind the Wax within the pores of the adsorbent, The wax is subsequently separated from the solid adsorbent. This process is unsatisfactory-because of the diiculty in obtaining satisfactory wax yields and the diculty of removing the wax from within the pores of the adsorbent` without use of a second solvent for the wax. V I

A major object of this invention is the pro vision of a new, improved and economical process for the separation of wax and liquid oils which overcomes many of the disadvantages of the prior art processes.

A specific object is the provision of a novel continuous process for the deoiling of slack wax bymeans of porous solid adsorbent materials.

These and other objects of this invention will become apparent from the following description of the invention.

There is disclosed in United States application Serial Number 31,948, led June 9, 1948, a process wherein the waxy stock such a slack wax is brought into intimate contact with a suitable particle form solid adsorbent material under temperature conditions at which the wax constituentsof the wax bearing oil are congealed and become and remain co-ated on the outer surface of the adsorbent particles while the noncongealedliquid oil constituents are sorbed into the pores of the adsorbent. Thereafter the wax is removed from the surface of the adsorbent leaving behind the adsorbent bearing in its pores the liquid oil. The oil may be subsequently sep arated from the adsorbent by any of a number of different methods. In order to obtain the optimum yields o-f wax, it is highly important in that process that the temperature be controlled such `that the waxy constituents in the waxy stock are in a congealed or crystallized state either prior to, or substantially immediately after being brought into contact with the solid adsorbent particles or are congealed substantially simultaneously upon lbeing contacted with the adsorbent.A Also, the waxy constituents are maintained in congealed condition at least until the step of Wax removal from the adsorbent.

The present invention is directed to an improved' ,method for continuously Vconducting` one form of the above described wax-oil separation process on a commercial scale. In a preferred form of the present invention the adsorbent particles are passed continuously through a rst region wherein the waxy stock is contacted while it is in liquid form. Conditions of the contacting are preferably controlled so that in eflect a lm of liquid waxy stock surrounds each adsorbent particle to a thickness of less than about 0.1 inch. Coated particles are substantially irnmediately cooled at least in part by dropping them through a body of a suitable cooling liquid in which the constituents of the waxy stock are insoluble, thereby causing the waxy constituents to congeal on the surface of the adsorbent particles. rThe adsorbent is then permitted to remain at the wax congealing temperature levels until the oily constituents of the waxy stock become sorbed into the adsorbent pores leaving the congealed waxy constituents on the surface thereof. The waxy constituents are then removed from the surface of the adsorbent by suitable means such as by melting or by physical means and the oily constituents may be later separately removed by suitable methods.

It will be readily understood by those skilled in the art that such expressions as congealed wax constituents and non-congealed liquid oil constituents and the like as used in describing and claiming this invention do not necessarily mean pure oil-free wax or pure wax-free oil since the amount of wax which will congeal from a wax-oil mixture is to some extent dependent upon the temperature of the mixture. For example, if the mixture were cooled to 90 F. some waxy constituents might congeal but in the non-congealed liquid oil there very probably will be present in non-congealed state some material which chemically should be classified as a wax. For the purposes of describing and claiming this invention a wax which is free of oil shall be taken as meaning one in which the oil content is zero as determined by the S. T. M. method for determining oil contents of waxy stocks, A. S. T. M. Test Number D721-43T.

The invention may be more readily understood by reference to the drawings attached hereto in which Figure 1 is an elevational flow plan, partially in section of a preferred form of the invention and Figure 2 is an elevational view,

partially in section, of a modified form of a portion of the system in Figure l. Both of these drawings are highly diagrammatic in form.

Turning now to Figure l for a description of the apparatus and its operation, a waxy stock such as slack wax is pumped by pump l0 through a heater or heat exchanger I I wherein it is heated to a temperature slightly above that at which the waxy constituents begin to congeal. The heated slack wax then passes via pipe I3 into the upper section of the elongated vertical vessel I4. A column of the molten slack wax is maintained within section A of the coating tower IA. A column of water or other suitable cooling liquid is maintained within a lower section of tower I4. This liquid should be of greater density than the slack wax and a non-solvent as to both wax and oil. The water in that portion of the tower I4 just below the slack wax column is maintained at a temperature sufficiently high to avoid congealing of wax at the interface between the slack wax and water column. This is accomplished by circulating water through pipe Il into and through heat exchanger I8 and back into the water column via pipe IS just below the interface. Cold water enters the water column via pipe 20 below the level of warm water outlet pipe I'I. Particle form porous adsorbent material which may preferably be of spherical form enters the tower i4 via pipe 2i at about the same temperature as the slack wax or at a somewhat lower temperature. In general, the inlet temperature of the adsorbent should usually be below about 100 F. and preferably below about F. The rate of introduction of adsorbent is controlled by adjustment of the height of the outlet end of pipe 2| from conical spreader 22 and by rotation of spreader 22. The spreader is rotated by means of gears 23, shaft 2d and motor 40. Upright conical bafies 25 and 26 supported by rods 2l and 2B are properly positioned below the spreader 22 in such a manner as to distribute the particles of adsorbent uniformly over the entire cross section of the tower lf3. The adsorbent particles drop downwardly through the column of slack wax and become coated on their surface with a film of slack wax. The particles then drop into the water column and the cool water acts to congeal the wax constituents on the surface of the particles. When the difference between the particle density and cooling liquid is small, it is desirable to add some substance such as potassium oleate, potassium stearate, diethanol amine, sodium wax phenol sulfonate, etc. to the water or other cooling liquid to lower the interfacial tension at the water-slack-wax interface. This will prevent hold up of adsorbent particles at this interface. The particles of adsorbent bearing the congealed material are washed by the water from the bottom of tower It through the curved pipe 29 onto a moving screen belt drainer 3U. The pipe 29 is provided with a vent 3I to break the siphon effect, and the leve1 of the highest point along pipe 29 is such as to maintain the surface of the wax column substantially constant as indicated in the drawing, the water introduced into tower I4 via pipe Zl being equal in volume to that passing from the tower through pipe 29.

The screen 3l] is of a continuous belt type, moving over rollers 32 and 33, one of which is driven by motor 34. The screen is encased in suitable housing 55. A pan 35 positioned under the screen catches the water which is withdrawn via ypipe 3S to accumulator (i I. The water is passed from accumulator 6| via pipe 62, pump 63 and pipe 29 back to the tower I4. Make up cooling water is added to the accumulator 5I via pipe 6d. The adsorbent particles bearing the congealed waxy material are retained by the screen and discharged into conveyor 3l. The adsorbent is discharged from the conveyor into one of the sorption tanks 38 and 38', these tanks being several in number although only two are shown and being employed in cycle. When one of the tanks 38 is lled, the adsorbent is permitted to stand therein while the temperature is controlled by means of heat transfer tubes (not shown) at a level at which the wax constituents of the slack wax will remain congealed. A suitable cooling fluid may be supplied to the heat transfer tubes within each of the tanks 32! via pipe 4I and withdrawn via pipe 42. The adsorbent is retained within the

tank

38 or 38 until substantially all of the non-congealed liquid oil constituents of the slack wax are sorbed from the congealed mass on the surface of the particles into the pores of the particles leaving substantially only the waxy constituents coated on the outer surface of the adsorbent particles. The adsorbent is then withurawnfthroughoutlets scendevano conveyed by screw conveyors 43 and 44 into the upper section of the wax melting tower 45 which is maintained substantially lled with a column of hot water. The adsorbent particles drop throughthe column of hot water in a-zig zag path provided by baiiies 48 so that the wax depositedvon the surface of the particles is melted'oiifV from the particles and is passed from the upper section of tower 45 via pipe 48 to the wax separator 49. The molten wax is withdrawn from the upper section of separator 49 via pipe 50 Vand the separated water is returned via pipe 109;" pump 5l and pipe 52 to the lower sectionfof the waxmelting tower 45. The water is maintained* substanl tially above the melting point of "thewax by means or" the heating coil 53 within'separator 49. The adsorbent particles 'which still retain the liquid oil within theA pores of the particles are carried from the bottom of tower 45 in a water stream Via conduit 54 and discharged' onto the moving belt screen drainer 66 'which is similar to the screen 38 described hereinabove. The highest level of conduit 54 is such as to permit maintaining tower 45 substantially lled with'liquid. The hot water passing through the screen 66 is eollected in pan lil and returned via pipe 68 and pump b9 to the separator 49. Hot water make up is added to the system via pipe lll. The iiltered adsorbent material passes from the end of moving screen 68 via duct 'Il into one of several oil removal tanks 'l2 and l2 (only two being shown). These tanks are used in cycle, the empty tank being opened to the duct 'l l. When one of the tanks l2 has become lilled to the desired level with adsorbent, itis closed off from duct l l, as'by stopping the rotation of the star valve 'I4 or 14', and a suitable oil solvent is introduced via conduit or l into the tank 12 or 12 and passed through the adsorbent mass until all the sorbed oil is removed. The solvent bearing removed oil is withdrawn from tank 'I2 via pipe y16 and the oil and solvent may then be separated in suitable equipment which is conventional in the art for that purpose. The solvent employed may be a hea-ted naphtha fraction, benzol, hexane, butyl alcohols, ethyl carbonate and acetone or other suitable oil sol-vents. After removal of the oil, the adsorbent is drained and then purged free of solvent by means of steam, ue gas or other suitable purge rluid entering via pipe 19. The purge uid is withdrawn from tank l2 viapipe 16. IIhe reclaimed adsorbent is then discharged from tank via pipe 88 and may be reused in the deoiling process.

After long periods of continued reuse a deposit ci carbonaceous material may accumulate on the adsorbent which is not removed in the reclaiming steps. Inasmuch as this material may eventually plug up the pores of the adsorbent and decrease its eiciency in the present process, the carbonaceous contaminant should be periodically removed from the adsorbent either by means of suitable solvents or by means of burning with air at elevated temperatures in a manner well known to those skilled in the art.

It will be readily understood that this invention is not limited to the particular details of apparatus arrangement or process step technique shown in Figure l. For example, a number of methods may be employed for accomplishing the initial coating of the surface of the adsorbent with the waxy stock. An alternative method is shown in Figure 2 in which is shown an apparatus arrangement which may be :substituted-for thecoating tower I 4 in the system ofFig'ur'e-i. i?! InrFlkuriZ, there is shown a coniinedelc'mga'tedv chamberv which may be suppliedwith'cold' waterithrough pipe 88 so `as to maintain al column 188.01 -cold water therein. The water is continuously Withdrawn from the upper section of vesselvia pipe 81 so as to permit continuous 'circulation of -the water through column 88. An adsorbent supply hopper 89 supplied with adsorbent viav pipe 9U is positioned above chamber 85. Aieed pipe; 94 extends vertically downward from hopper 89 into chamber 85 and terminates a substantial distance below the surface level of thewater 'column in chamber 85 but preferably within the-upper section of the water column. A slack wax-supply hopper S2 is also positioned above thechamber 85l and a pipe 93 extends downwardly from hopper 92 to connect into feed pipe 94 a short distance above the surface level of the water column 88. Slack wax is heated in heater l I0 and supplied to hopper 92 in molten condition. It then flows via pipe 923 into pipe 94 where it mixes with adsorbent from hopper 89 at a temperature only slightly above the congealing temperature of the Wax'constituents of the slack wax charge. The liquid charge stock fills in the void spaces between the stream of solid particles flowing in pipe 94 and solidies as the stream reaches the column of cool water 88. lIf desired, the congealing of the wax may be aided vby supplying the adsorbent from hopperi89fat av temperature somewhat below that required to congeal the wax constituents of the molten 'slack wax charge. Due to the head of adsorbent in pipe 94 above the solidified mass nearA its outlet,l a rod or ribbon of adsorbent encased `in rsolidified waxy charge stock is extruded from-the lower end of pipe 94 into the water column. 'I'he extrusion may be aided, if desired, by a mechanically agitated rod or other suitable device I Il within the lpipe 94 which may be operated from anexternal location above the hopper 89. The-rod or ribbon of extruded material drops through the column of .cooling water 88 and becomes'further cooled so 'as to complete the congealing of thewaxy constituents throughout the cross section of the ribbon. The extruded ribbon may be caused to break up to some extent into chunks of solidied charging stock encasing adsorbent particles as it r`falls through the water column 88 and the material is removed from the lower sectionV of `the chamber 85 by means of the continuous bucket conveyor 99 which connects into chamber 85.. The buckets 198 of this conveyor may be perforated so as to permit draining of liquid from the mass of adsorbent particles encasedin cong'ealed waxy stock once the buckets rise above the surface level of column B8. If desired, the adsorbent may be further drained free of water by delivery from conveyor 99 into the drainer 55 'shown in Figure 1. In many operations adequated'raining may be accomplished as the material is elevated in conveyor 99 and the adsorbent may be conveyed directly to the

adsorption tanks

38 and 38 shown in Figure 1.

When the method described in Figure 2 is ernployed, the pipe 94 should preferably be subdivided near its lower end by means of vertical partitions so as to form a number of vertical passages having a maximum horizontal average diameter of about one half inch in diameter. 'I'he diameter of the ribbons is thereby limited to a size which will permit rapid transfer of heat into the center of the ribbons so as to accomplishquick congealing of the wax throughout the ribbon c'ross section. In general, the pipe 94 should extend about 0.5 to 10 inches below the surface of water column88 depending on the water temperature, and being less the lower the water temperature and higher the congealing temperature of the waxy constituents. The waxy stock should enter the pipe 94 about 0.5 to 24 inches above the surface of water column 88.

It will be readily understood that apparatus and methods other than that shown in Figure 1 may be employed to accomplish the transfer of materials between vessels, the adsorption step and the draining and wax melting and oil recovery steps. Moreover, the removal of wax from the surface of the adsorbent particles may be accomplished by methods other than by the melting of the wax. For example, the wax may be removed from the particles while in solid form by mechanical attrition. This latter method is particularly applicable when the wax is of brittle texture and where the adsorbent particles are spherical in form. One method for accomplishing the mechanical separation is to rotate the adsorbent particles in a closed drum for a period of time to crack off the brittle wax. The particles of wax may then be separated from the adsorbent particles by elutriation, i. e. suspension in a stream of gas the flow rate of which is controlled to carry off the wax particles without entraining the adsorbent.

The step of removing the oil from the pores of the adsorbent particles may be accomplished by methods other than those employing oil solvents. For example, the adsorbent may be heated and steamed to remove the oil.

A wide variety of porous adsorbent materials may be employed in the process of this invention. For example, bauxites, fullers earth, activated charcoal, synthetic silica-alumina or silica and alumina gel catalysts and other materials of similar porosity. Certain porous sorptive silica glasses such as are described in United States Patent 2,106,744, issued February l, 1938, to Hood et al. may be employed, In general, the pore size of the adsorbent material should be adapted to eiect rapid sorption thereinto of the oily constituents of the waxy charge stock. The adsorbent particles should be of substantial size as distinguished from powdered adsorbents. When powdered adsorbents of size less than about 100 mesh Tyler are employed the waxy constituents tend to be sorbed into the pores along with the oily material before complete congealing of the waxy constituents can be accomplished thereby preventing the desired separation. In general, it has been found that the adsorbent particles should be broadly at least about 0.01 inch average diameter and preferably at least about 0.022 inch and less than about 0.5 inch average diameter. A preferred adsorbent is a synthetic silica-alumina gel catalyst in spherical form prepared in the manner described in United States Patent 2,384,946, issued September 18, 1945, to Milton M. Marisic. Y

In conducting the methods described in connection with Figures l and 2, the temperature of the waxy stock as brought into initial contact with the adsorbent should preferably be only several degrees above that at which the waxy constituents will commence to congeal. The temperature of the cooling fluid employed to cause the congealing of wax constituents and to maintain them congealed during the sorption period will of course vary somewhat depending on the melting point of the waxy constituents involved. For many operations, a cooling water temperature of about '70 F. has been found satisfactory. The operation should be conducted so as to effect congealing of the waxy constituents as soon as possible after the initial contacting with the adsorbbent. The waxy constituents should be congealed at least within about 10 minutes of the initial contacting and preferably within about less than one minute thereof.

The ratio of adsorbent to waxy charge stock employed in the process of this invention will depend to some extent upon the oil sorption capacity of the adsorbent, the percentage of oil present in the waxy stock and other operating variables. In general, for synthetic gel catalysts the ratio should be of the order of 0.5 to 10 pounds of adsorbent per pound of waxy stock. In any case, suiiicient adsorbent should be employed to Sorb substantially all of the oily constituents in the waxy charge.

The length of time to be devoted to the sorption period during which non-congealed liquid constituents are sorbed into the pores of the adsorbent will vary depending upon the thickness of the waxy stock coating cn the adsorbent particles and upon the particular adsorbent involved and the viscosity and molecular size of the oily constituents under the sorption temperature conditions required to maintain the waxy constituents in a congealed state. In general, it has been found that with adsorbent particles of about 0.09 to 0.19 inch diameter and having a porosity similar to a synthetic silica-alumina gel catalyst, the length of the sorption period should be at least about 0.1 hour and should preferably be of the order of about 1 to 24 hours.

In general, the average thickness of the waxy stock coating around each adsorbent particle should be less than about 0.1 inch and preferably less than about 0.05 inch. In the method disclosed in Figure 1, the wax coating is limited below 0.1 inch thickness by proper control oi' the temperature of the adsorbent and waxy stock. In the method of Figure 2, the effective coating thickness is controlled by proper control of the waxy stock to adsorbent feed ratio to the ribbon forming zone.

As an example of the process of this invention, the deoilng of .a waxy stock by the general method shown in Figure 1 may be considered. The waxy charge stock was a parafnic petroleum stock having a melting point of 116.9 F. as determined by the test procedure recommended by the American Society for Testing Materials, Test. Number A. S. T. M. D87-42 and an oil content of 19.2 as determined by A. S. T. M. tentative Test Number D721-43T. The adsorbent employed was a synthetic silica-alumina gel bead catalyst prepared by the method described in United States Patent 2,384,946, dated September 18, 1945. The catalyst had a bulk density of about .74 as determined by pouring the catalyst into a measured container and weighing. The individual particle density was about 1.15. The catalyst particle size was about 0.09 to 0.19 inch diameter. The catalyst beads were dropped through a column of molten waxy stock one inch in depth and maintained at about 126 to 133 F. The weight ratio of catalyst to waxy stock charge was about 3.5 to l. The catalyst beads bearing a coating of waxy stock then dropped through a column of cooling water maintained at about 70 F. About 0.3-0.5% potassium oleate was added to the water t0 redluce the interfacial tension at the water wax interface. The catalyst bearing the congealed coating of waxy stock was permitted to stand for about 4 hours at about F. after which the wax was removed by attrition from the surface of the particles. The

recovered wax had a melting point of 1353" F. and an oil content of 3.2% by weight and the yield of recovered wax amounted to 58% by weight based on the waxy stock charge or 72% by weight of the wax present in the charge as determined by A. S. T. M. Test Method D-72l- 43'1. By Way of comparison, the yield of wax obtained by the method described above using a minimum cooling water temperature of 70 F. amounted to 83% by weight of the yield of wax obtained by solvent deoiling the same waxy stock employing benzol-methyl ethyl ketone as the solvent at a temperature of Zero degrees F. The wax obtained by the solvent deoiling process contained 2.4% by weight oil.

In another experiment employing the same conditions, outlined above except that the sorption period was increased from` 4 to 20 hours, a final wax product containing only 1.4 oil was obtained but the wax yield based on the charge was somewhat lower.

In still another experiment conducted similarly to the one first described, the sorpt-ion period was increased from 4 to 20 hours and the adsorbent to oil charge ratio was decreased from 3.5 to about 1.4. The wax yield was increased to 61% by weight of the original waxy charge but the oil content in the recovered wax increased to about 6.7% of the wax.

In another experiment conducted according to the method described in connection with Figure 2, a waxy charge stock having a melting point of ll3.5 F. and an oil content of 20.3% oil by weight was.` deoiled employing the same adsorbent. Referring to Figure 2, the adsorbent feed pipe @d measured one half inch` internal diameter and molten charge entered the pipe 96 about oneV inch above the surface of water column 88. The one half inch rod extruded from pipe Bil dropped into a cold water bath maintained at about '70 F. The adsorbent to waxy charge stock weight ratio was about 1.8 to 1.0. The extruded material was permitted to stand at 80 F. for 3 hours after which the wax was removed by attrition in a ball mill. The wax yield amounted to 68% of the wax present in the charge stock as determined by A. S. T. M. tentative test Number D-721-43'I and the wax product contained 4.3% oil and had a melting point of 123.3 F.

It should be understood that the.l specific details of operation and of apparatus arrangement and the specific modifications of this invention given hereinabove are intended as exemplary and the invention is not to bei construed as being limited thereto or otherwise limited eXcep-t as limited by the following claims.

I claim:

l. The method for separating wax and oily constituents present in waxy hydrocarbon stocks which comprises, continuously passing particles of a suitable solid adsorbent of at least 0.01 inch average diameter into contact with said waxy stock existing in the liquid phase in a contacting region, withdrawing the contacted adsorbent particles with waxy stock on the surface thereof from said contacting region before any substantial amount of the wax constituents are sorbed into the pores of the adsorbent particles and substantially immediately dropping the particles downwardly through a body of a suitable cooling liquid in which the constituents of the waxy stock are insoluble to effect congealing of the waxy constituents on the surface of the adsorbent particles, withdrawing the chilled adsorbent from said body of liquid and then maintaining the coated particles under conditions in which said'waxy constituents remain in congealed condition in a separate region until substantially all of the non-congealed liquid constituents of said waxy stock are sorbed into the pores of said particles, leaving the congealed waxy constituents on the surface of said particles and thereafter effecting removal of the waxy constituents from the surface of said adsorbent particles while leaving said liquid constituents within the pores of the adsorbent.

2. The method for separating wax and oily constituents present in waxy hydrocarbon stocks which comprises, continuously passing particles of a suitable solid adsorbent of at least 101 inch average diameter into contact with said waxy stock existing in the liquid phase in a first region to effect coating of waxy stock as a liquid onto the surface of the particles of solid adsorbent, controlling the conditions of contacting so as to limit the average thickness of waxy stock coating on the particles below about 0.1 inch, limiting the length of contact time in said first zone below that at which any substantial amount of the Wax constituents would be sorbed into the pores of said adsorbent, then substantially immediately effecting congealing of the waxy constituents on the surface of said adsorbent at least partly by withdrawing the coated adsorbent from said first region and dropping the adsorbent downwardly through a body of a suitable cooling liquid in which the constituents of the waxy stock are insoluble maintained in a second region below said first region, withdrawing the chilled adsorbent from said body of liquid and then maintaining the coated particles under conditions in which said waxy constituents remain in congealed condition in a separate region until substantially all of the non-congealed liquid constituents of said waxy stock are sorbed into the pores of said particles, leaving the congealed waxy constituents on the surface of said particles and thereafter effecting removal of the waxy constituents from the surface of said adsorbent particles while leaving said liquid constituents within the pores of the adsorbent.

3.l The method of claim 2 further characterized in that the coated adsorbent is cooled in said second region within less than one minute of the time of the initial contact of the adsorbent with waxy stock in said first region.

4. A method for deoiling wax-oil petroleum stocks which comprises: maintaining a liquid column of said wax-oil stock at a temperature slightly above that at which the waxy constituents begin to congeal, maintaining below and contiguous with the bottom of said column of wax-oil stock a column of Water, circulating the water in the upper portion of said column thereof through an external heater and then back into the upper portion of said column to maintain the temperature of the water in the upper portion of the water column near that of the wax-oil stock, introducing cold water into the intermediate portion of said column to maintain the temperature in the remainder of said water column at a temperature at which the waxy constituents of said stock will congeal, dropping particles of solid adsorbent comprising particles of at least 0.01 inch average diameter downwardly through said column of waxoil stock to cause said particles to become coated with wax-oil stock, causing the coated particles to drop downwardly into and throughsaid column of water to cause the .waxy constituents in the stock coating said particles to become congealed, removing the particles bearing the coating of wax-oil stock from `said water `co1- umn along with some of the cold water, and thereafter maintaining the coated particles at a temperature below the congealing temperature of said waxy constituents until substantially all the non-congealed constituents of the wax-oil stoel; coating said particles are sorbed into the pores of said adsorbent particles while leaving the waxy constituents on the surface yof said particles, then removing the waxyfconstituents from the surface of said particles and collecting the waxy constituents lseparately ofthe adsorbent particles and said sorbed oily'constituents.

5. A method for separating oily constituents vfrom waxy constituents present in a waxy hydrocarbon stock which comprises: continuously passing particles of asuitable solid adsorbent of at least 0.01 inch average diameter downwardly by gravity through a rst region whereinsaid particles are brought into intimate `contact with said waxy stock, whereby some of the waxy stock -becomes coated around the surface 'of each adsorbent particle, said iirst region being maintained at a temperature at which said waxy stock is present in the liquid phase, then before the waxy constituents can -beceme sorbed into the pores of said adsorbent particles, passing the adsorbent downwardly through a cooling region toefiect congealing of the waxy constituentson the surface of said particles, maintaining va b'ody of suitable cooling liquid throughout `at least a substantial portion of said cooling region and causing the adsorbent particles to drop downwardly through said body, withdrawing the ladsorbent from said body of cooling liquidand maintaining it at a temperature at which-saidf-waxy constituents remain-congealed until-substantially all ol the oily constituents of the stock coated on the particles becomes sorbed into the -ipores of the particles leaving the `waxy constituents on the surface thereof, thereafter effecting removal of the waxy constituents from the surface of said particles while leaving the non-congealed oily constituents still sorbed in the pores ofthe particles.

6. A method for deoiling waxoil-petroleum stocks which comprises: maintaining a liquid column of said wax-oil stock ata temperature slightly above that at which the waxy constituents begin to congeal, dropping particles of solid adsorbent material of at least 0.01 inch average diameter through said column to deposit a film of said waxy stock on the surface of said adsorbent particles, controlling the temperature of the waxy stock and of the adsorbent particles ,supplied to said column to limit the thickness of said lm on said particles below about 0.1 inch, substantially immediately cooling said adsorbent particles to effect congealing of the waxy constituents of said wax-oil stock, :permitting the adsorbent particles to remain coated with said wax-oil `stock while maintaining the waxyconstituents in a congealed state until substantially all the noncongealed-constituents are sorbed into-the pores of said particles, thereafter effecting removal of the waxy constituents from the surface-of said adsorbent particles while leaving sai-d nonccngealed liquid constituents sorbed in thepores of said particles -and separately .eiecting: removal of the sorbed liquid from the wax free adsorbent particles.

7. A method for deoiling wax-oil petroleum stocks which comprises: maintaining a liquid column of said wax-oil stock at a temperature slightly above that at which the waxy constituents begin to congeal, dropping particles of solid adsorbent material having an average particle diameter of at least 0.01 inch through said column to deposit a nlm of said waxy stock on the surface of said adsorbent particles, immediately dropping said adsorbent particles bearing said film of waxy stock into a bath of a suitable cooling liquid maintained at a temperature suitable for congealing the waxy constituents of said wax-oil stock, permitting the adsorbent particles to remain coated with said wax-oil stock while maintaining the waxy constituents in a congealed state until substantially all the non-congealed constituents are sorbed into the pores of said particles, thereafter eiecting removal of the waxy constituents from the surface of said adsorbent particles while leaving said non-congealed liquid constituents sorbed in the pores of said particles and separately effecting removal of the sorbed liquid from the wax freed adsorbent particles.

8. A method for deoiling waxy petroleum fractions which comprises: converging together a stream of said waxy fraction in liquid form with a stream of particle form solid adsorbent material of at least 0.01 inch average particle diameter in a conned zone whereby the liquid waxy stoel: nlls in the void spaces in the stream of adsorbent particles, chilling the resulting mixed stream to effect congealing of wax constituents of the waxy stock and extruding a ribbon of the mixed adsorbent particles and waxy stock into a suitable bath of cooling liquid to effect further congealing of wax constituents of said waxy stock, maintaining the extruded and chilled ribbon at a temperature at which the wax constituents will remain congealed until substantially all the noncongealed liquid constituents of the waxy fraction are sorbed into the pores of the adsorbent `particles while the waxy constituents remain coated on the surface oi said particles, then removing the waxy constituents from the surface of said particles and separately removing the noncongealed liquid constituents from the pores of said adsorbent particles.

9. A method for deoiling wax-oil petroleum stocks which comprises: maintaining a liquid column of said wax-oil stock at a temperature slightly above that at which the waxy constituents begin to congeal, maintaining below and contiguous with the bottom of said column of wax-oil stock a column of water, maintaining a short length of the column of water immediately below the column of wax-oil stock at a temperature near that of the wax-oil stock and maintaining the remander of .said column of water at a temperature at which the waxy constituents of said stock will congeal, dropping particles of solid adsorbent comprising particles of at least 0.01 inch average diameter downwardly through said column of wax-oil stock to cause said particles to become coated with wax-oil stock, causing the coated particles to drop downwardly into and through said column of water to cause the waxy constituents in the stock coating said particles to become congealed, removing the particles bearing the coating of wax-oil stock lfrom said water column and permitting the'particles to stand at a temperature below the congealing temperature oi' said waxy constituents until-subsantially all the non-congealed constituents of the Wax-oil stock coating said particles are sonbed into the pores of said adsorbent particles while leaving the WaXy constituents on the surface of said particles, then removing the waxy constituents from the surface of said particles and collecting the waxy constituents separately oi the adsorbent particles and said sorbed oily constituents.

10. The method of claim 9 characterized in that the water in at least the upper portion thereof contains a suitable added material to reduce the interfacial tension at the water-waxy stock interface.

1l. A method for deoiling slack wax which comprises: forming a solidified ribbon consisting of particles of a suitable porous solid adsorbent rnaterial of greater than about 0.01 inch average diameter surrounded by the slack wax in which the waxy constituents are substantially crystallized, maintaining said ribbon at a temperature at which the Wax constituents remain solidified `for a period of at least 0.1 hour until substantially all the liquid oily constituents are sorbed in the pores of said adsorbent particles leaving the crystallized wax on the surface of said particles, then removing the wax from the surface of said particles in a separate Zone while leaving the liquid oily constituents sorbed in the pores of said particles, iinaily separately removing the oily constituents from. the pores of said particles and reusing said particles to decil additional slack Wax as aforesaid.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 2,537,999 Hermanson et al. Jan. 16, 1951 2,581,573 Biles et al Jan. 8, 1952

Claims

1. THE METHOD OF SEPARATING WAX AND OILY CONSITITUENTS PRESENTS IN WAXY HYDROCARBON STOCKS WHICH COMPRISES, CONTINUOUSLY PASSING PARICLES OF A SUITABLE SOLID ABSORBENT OF AT LEAST 0.01 INCH AVERAGE DIAMETER INTO CONTACT WITH SAID WAXY STOCK EXISTING IN THE LIQUID PHASE IN A CONTACTING REGION, WITHDRAWING THE CONTACTED ADSORBENT PARTICLES WITH WAXY STOCK ON THE SURFACE THEREOF FROM SAID CONTACTING REGION BEFORE ANY SUBSTANTIAL AMOUNT OF THE WAX CONSTITUENTS ARE SORBED INTO THE PORES OF THE ABSORBENT PARTICLES AND SUBSTANTIALLY IMMEDIATELY DROPPING THE PARTICLES DOWNWARDLY THROUGH A BODY OF A SUITABLE COOLING LIQUID IN WHICH THE CONSTITUENTS OF THE WAXY STOCK ARE INSOLUBLE TO EFFECT CONGEALING OF THE WAXY CONSTITUENTS ON THE SURFACE OF THE ADSORBENT PARTICLES, WITHDRAWING THE CHILLED ADSORBENT FROM SAID BODY OF LIQUID AND THEN MAINTAINING THE COATED PARTICLES UNDER CONDITIONS IN WHICH SAID WAXY CONSTITUENTS REMAIN IN CONGEALED CONDITION IN A SEPARATE REGION UNTIL SUBSTANTIALLY ALL OF THE NON-CONGEALED LIQUID CONSTITUENTS OF SAID WAXY STOCK ARE SORBED INTO THE PORES OF SAID PARTICLES, LEAVING THE CONGEALED WAXY CONSTITUENTS ON THE SURFACE OF SAID PARTICLES AND THEREAFTER EFFECTING REMOVAL OF THE WAXY CONSTITUENTS FROM THE SURFACE OF SAID ADSORBENT PARTICLES WHILE LEAVING SAID LIQUID CONSTITUENTS WITHIN THE PORES OF THE ABSORBENT.