US2534210A

US2534210A - Centrifugal separation

Info

Publication number: US2534210A
Application number: US650792A
Authority: US
Inventors: Schutte August Henry; Ward F O'connor
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1946-02-28
Filing date: 1946-02-28
Publication date: 1950-12-12
Anticipated expiration: 1967-12-12

Description

De@ l2, 1950 A. H. scHuTTE Erm. 2,534,210

CENTRIFUGAL SEPARATION Filed Feb. 28, 1946 f eiraxnple.andy an inert gas, such: as air.

4 q ,Patents Nos. 2,394,015 and 2.394,016fboth` `issued.. aryfs. 1946 @notam entitledgcentrifugai separa- ,t,ip riff;,y further ydisclose vIm'ovision for suillcient residence time ofthemixture within a centrifuge ratented Dec. 12,1950

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i This Iinvention l' relates ,se Patent me. riesgos., issued top A. H.

`semina,August -1,. 1939, undermined Method of j Separating Wai, discloses v.af wax-oil separation.:process` wherein, the wax-oil mixture, prior tointroduction `,thereof to `a centrifuge, is emulsined witha non'solvent liquid such as water, for

...toa H. Schutte and A. W. Mack, Februof the solid-bowl type. to obtain more complete separationof theoil `andwaxfand provision `for discharge .of the oil Aand thel non-solventv liquid ofI theemulsionfrom the centrifugein a manner to. prevent .'dischargeiggof. wax therewith. More particulilarly,',said ypatents disclose. provision for discharge ofcompletely separated wax from a pointfwithin the .centrifuge Yspaced radially inyward from the circumferential. wall of the centrifuge,` provisionvlfor discharge of the oil and the nonfsolvent liquid, completely separated from Lthe' waar,v from la pointwithinthe centrifuge ,located betweenmsaid wall and said point of' wai;A discharge"end alsoprovisionfcr retention ofv af layerofthe eiland submerged wax in a radial. position betweensaid .discharge points in order tolprevent" discharge fromsaid layer.

to bring them b al .t0 .thisforiginal position to i important Aobject of the presentinvention is` toprovide for preparation and delivery of the emulsion charge tothe centrifuge in an improved manner to obtain lmore conveniently and reliably the advantages taught` by the disclosures of the aforesaid patents. .A furtherobject of the invention" is'to provide, for automatic control of the charging fof the centrifuge inza manner to ensure Aretenticnof the layer o'ftoil and submergedwax in radial' position withinthe centrifuge betweenv thedisc'harge point of the separated wax and the discharge 'point -of the liquid separated fromthe Wax. l V

l centrifugal separa- ,.tiomof-arnixture of materials having pdiierent specic-gravities, such, as a waxeoil mixture-forlv :.examrileyI .f

sibu'eauoudzrebruary as. museum Nessmm Y i scum. (crass-4u j -Inthedrawing: a' Fig. 1 is a view of the improvedcentrifuge and the improved charging system therefor, the centrifuge being shown in vertical section andthe -illustration of thev charging system being partLv diagrammatic; and

, Fig. 2 is a vertical sectional perspective view .of an-improved structural detail of the centrifuge,

stillffurther'obiect of the-invention is to I provide, in a. centrifuge,V an' improved structure for e'lnectlng'the said discharge of the wax and theV separated liquidffrom .radially Vspaced points. "y These and other objects and advantages of the inventionwill appearlfrom `the following descriptiontalrenin connection'with the accompanying upon a larger scale than Fig. 1.

. f According to the invention, air and water or other suitable liquid, non-solvent with respect to the oiland the wax,` are continuously delivered to the wax-oil mixture prior to introduction ofl the mixture to the centrifuge andthe mixture with the added liquid and air are subjected to a mixing operation to form an emulsion. A portion of the added water is obtained from a source outside of the charging system and its temperature is sufficiently low to chill and solidify the wax component of the mixture for emcient'separation of the wax from the. liquid components ofthe vcharge by centrifuging. Another portion of the added Water is obtained from the liquid discharged from the centrifuge` Said discharge comprises oil and water separated from the wax.

The water of the discharge, or a substantial por' tion thereof, is separated from-the oil by settling f and supplied in an amount required to the centrifuge charge to supplement the supply of said -temperature-conditioning water of the charge. In the course -of charging the centrifuge the supply of temperature-conditioning water is varied to satisfy temperature-conditioning requirements, and the supply of the said vseparated water is varied to compensate for the variations in the supply of the temperature-conditioning water and maintain a substantially uniform combined delivery of temperature-conditioning water and separated water to the centrifuge. Since the separated water has been previously temperatureconditioned by employment in the charging and centrifuging steps, addition thereof to the charge does not interfere with the temperature-control obtained through variation of the amount of tem'- perature-conditioning liquid delivered to the charge.

The maintenance of a substantially uniform combined delivery of the temperature-conditioning water and the separated temperature-conditioned `water to the centrifuge is for the purpose of retaining a layer of incompletely separated components of the charge in a desired radial position within the centrifuge. This layer comprises-oil with a portion of the.wax cake submerged therein. The centrifuge is devised to the centrifuge bowl.

inward from the circumferential wall of the rotor and to discharge the oil and water, separated from the wax. from a point radially located between said wax discharge point and said wall. By maintenance of a certain correlation of the said combined delivery and the liquid discharge capacity of the centrifuge for a given rate of rotation of the latter the said layer of oil and wax is retained in a radial position between the points of discharge of the separated liquid and the separated wax. Thereby, discharge of wax with the liquid and liquid with the wax is prevented.

According to the invention, the delivery of temperature-conditioning water and the delivery of tempertaure-conditioned water for compensating elfect are both automatically controlled. The invention provides a. system for preparing the charge and delivering it continuously to the centrifuge and they system includes temperatureresponsive means to vary delivery of the temperature-conditioning liquid to the charge as required and also means responsive to such variation to vary delivery of the temperature-conditioned water in order to maintain automatically a substantially uniform combined delivery. The invention also provides for alteration of said uniform combined delivery and also for alteration of the liquid discharge capacity of the centrifuge and for changing the radial position of the wax discharge point.

The centrifuge employed is of a solid-bowl type as distinguished from the filtering type. In the present instance, the bowl or rotor I of the centrifuge has a cylindrical, imperforatecircumferential wall and an imperforate bottom wall. A shaft 2 is aillxed to the bottom wall, for rotation of the bowl, and may be driven from any suitable power source, not shown. A flat, annular baule 3 is secured to the bottom of the bowl in a position spaced upwardly therefrom and is disposed concentric to the -axis of the bowl, with its outer edge spaced from the surrounding circumferential wall of the bowl. At the upper end thereof, the bowl has an inwardly extending annular lip 4. In thepresent instance, this lip comprises an annular outer section 4a of frusto'- conical form and a at annular inner section 4b detachably secured to the outer section, as by screws 5, and extending radially inward from the equidistant from the axis of the bowl and spaced radially inward from the circumferential wall of the bowl. These apertures serve as discharge ports for liquid separated from the wax, and the inner edge of the lip section 4b defines an outlet for discharge of completely separated wax from the centrifuge.

A cylindrical housing 9 substantially encloses Within the upper portion of the housing, there is an annular member il) having an upstanding wall and an outwardly extending wall joined to the surrounding Wall of the housing and forming therewith a trough il to receive the wax discharged from the bowl. A pipe I2 provides for withdrawal of the wax from the trough. At the upper edge thereof, the trough-forming member l has an annular ange Ila extending radially inward to overlie the apertures 8 of the bowl lip.4 This flange is disposed below the level of the lip section 4b. 'I'he circumvzo ferential wall of the housing has a surrounding upper jacket I3 at the level of the trough H, and a surrounding lower4 jacket I4 extending from the jacket Il to the lower end of the housing.'

The upper Jacket is supplied with steam to liquefy the wax within the trough by indirect heat exchange, and water is passed through the lower jacket to temperature-condition the lower zone of the housing and its contents. A pipe I leads from the bottom ot the housing to conduct therefrom water and oil discharged from the centrifuge bowl. This pipe delivers to a.` settling tank I i within which at least a portion of the water settles from the oil. The oil and the remainder of the water are withdrawn from said tank by a pipe Il and a pump Il.

TheY system for continuously preparing the charge and continuously delivering it to the centrifuge includes a pipe II provided with a pump 23 and through winch the wax-oil mixture or' other mixture to be separated is supplied. `A pipe 2i is connected to pipe II, at the delivery side of the pump 20,' to deliver to the mixture air under pressure. Pipe 2| has a valve 22 to control said air delivery. Another pipe. 23, is connected to the pipe I! for delivery thereto of water or other suitable non-solvent liquid for emulslilcation with said mixture and also for temperature-conditioning the mixture. Pipe 2l leads from a source, not shown, of non-solvent liquid. En route to the pipe I9. the non-solvent liquid within the pipe 23 is supplied as required with temperatureconditioned water from the settling tank It. 'A pipe 24 leads from the bottom of tank II to the inlet of a pump 25 to conduct the settled-out water thereto, and said pump delivers said water through a pipe 2t tc the'pipe l23. Pipe i9 is in delivery connection with a mixing or emulsifying device to pass thereto the combined charge of wax and oil and the water delivered through the

pipes

23 and 26. As indicated, the emulsifying device may comprise a rotary pump 21 having a discharge pipe 28 and a recycle pipe 2! leading from the pipe 28 back to the pipe il, at the inlet side of the pump. A manually adjustable pressure control valve 30 is connected to the pipe 28, beyond the point of connection of the recycle pipe thereto. From the valve 30, a pipe 3i leads to the centrifuge to deliver thereto the emulsiiled charge. Preferably, as shown, pipe 3| extends downwardly within the centrifuge bowl, along the axis of the bowl, and is formed to discharge the emulsion into the space between the annular baie 3 and the bottom of the bowl.

Provision is made for automatic control of delivery of water through the pipe 23 in accordance with temperature-conditioning 4requirements of the charge within pipe 28. For that purpose, pipe 28 is provided with a thermostat 32 operatively connected, as at 33, with a thermoresponsive device 34. The latter is, in turn, operatively connected, as at 35, with a valve 36 in the pipe 23 so that temperature variation of the charge Within pipe 28 will cause operation of the valve to increase or decrease the delivery of temperature-conditioning water as required to mainytain the charge at a required temperature.

Provision is also made for automatic control of delivery of temperature-conditioned water to the charge in order to maintain a substantially uniform combined delivery of the water supplied through thepipe 23 and that supplied through the pipe 26. For that purpose, pipe 23 is provided with an orifice device 31 located between the point of connection of pipe 28 with the pipe 23 e, s and the connection oi pipe 23 with pipe I9. The orifice device is operatively connected, as indi-v cated kat 33, with a flow control device 39. The latter device is operatively connected as at 40, witha valve 4I in the pipe 26 so that variation in delivery of water through the oriilce device will cause actuatien ofthe device 39 to operate the'valve 4I .to increase or diminish deliveryof water through the pipe 29 in order to compensate;

The thermo-responsive device 34, the orifice device 31, and the flow control device 39 may be of standard types. Their specic constructions form no part oi.' thek present invention and detailed illustration and description thereof is omitted in order to'simpliiy the disclosure. The device 34 may be of a type known as a Recording temperature controller and the device 39 may be of a type known as a "Recording flow controller.

yIn the operation of the separating apparatus, the wax-oil cr other mixture to be separated is continuously delivered by the pump through the pipe I9 .tothe emuisifying device 21 along with air-'continuously delivered to the pipe I9 through the pipe 2l and water delivered through the pipe 23. The combined charge of wax-oil mixture, air and water is recycled as required through the pipe 29 to the emulsifying device, and the pressure control valve 39 maintains a required pressure within the emulsitler to obtain the desired degree ci emulsiilcation. Through the pipe 3I, the emulsion is continuously delivered to the centrifuge bowl and discharged beneath the baille 3. Said baille directs the charge radially outward to the circumferential wall of the bowl and the charge then flows upwardly throughnthe narrow annular space between said wall and the outer edge of the baiiie and into the separating zone above the baille. There, the charge is separated by centrifugal force into concentric layers including a layer W of water, a layer O of oil, a layer S of oil with wax cake submerged therein and a layer C of wax cake, said layers being named in the order of their apprcach to the centrifuge axis.

As previously mentioned, and as disclosed in the aforesaid patents of Schutte and Mack, it is desired that only the water and oil from the layers W and O be discharged through the apertures 8 of the bowl lip 4, that only the separated wax from the 4layer CA be discharged past the inner edge ofthe lip and that the intermediate layer f S of oil and submerged wax cake be retained in a radial position between said apertures and the inner edge of the lip. The present invention provides forautomatic retention of the layer S in that position by automatic control of the volume operation and the discharge capacity'of the centrifuge through the lip apertures 9. Thereby, the ldesired thickness of the water layer W is retained to radially position the layer S properly and prevent discharge therefrom through' either of said outlets.y At the same time, the invention preserves proper temperature control by the employment of previously used, and therefore temperature-conditioned, water as make-up to comof -water delivered with reference to the speed of i pensate for variation in delivery of temperatureconditicning water to the charge.

. The delivery of temperature-conditioning water through the pipe 23 is made subject to the` temperature of the emulsion charge within the pipe 28. A rise inl temperature of the charge above that required,v causes actuation of the thermo-responsivedevice 34 to operate the valve 36 for increased delivery ofwater through the pipe 23. A reduction in temperature cf-the charge below that required causes actuation of the device 34 to operate the valve 36 for a required reduction in delivery through the pipe 23. In response to such fluctuation in delivery through the orlnce device 31, the ilow control device 39 is actuated to cause operation of the valve 4I for increased or decreased delivery of temperatureconditioned water-as required to maintain the combined delivery of water by the pipes 23v and 29 substantially uniform.

The water for delivery through the pipe 26` is obtained from the layer W within the centrifuge. Water and oil together are discharged from the layers W and O respectively through the lip apertures 8. The flange Ilia of the annular trough-forming member I0 serves as a baille to deilect such discharge downwardly to the bottom of the housing 9. There, said discharge is collected and conducted by the pipe I5 to the settling tank I6. Water settles from the oil within said tank and is delivered to the supply pipe 26 by the pipe 24 and the pump 25.

Since the lip 4 of the centrifuge bowl is detachably secured to the bowl and is formed of the detachable sections 4a and 4b the radial location of the discharge point for the wax and the radial location and the discharge capacity of the apertures 3 may be varied to suit different charges and diierent operating conditions. The lip section 4b may be readily detached and replaced by another section of different internal diameter, and the outer section 4a may also be detached and replaced by one having a different number of the apertures 8 or having apertures of diii'erent size or different radial location. In cooperation with this adjustment feature, the flow control device 39 may be readily adjusted by means oi' its knob 39a to adjust the maximum water feed with relation to a particular adjustment,

gf tlhe points of discharge from the centrifuge While the invention is described as employed for the separation of a wax-oil mixture, it is well adapted for use in the separation of other liquid-solid mixtures and also for 'separation of purely liquid mixtures.

It is, of course, to be understood that the present disclosure of our invention is merely illustrative and in nowise limiting and that the invention comprehends such modifications as will come within the scope of the following claims.

We claim':

l. Separating apparatus, comprising a centrifuge oi.' the solid-bowl type operable to separate a fluid mixture of materials of different specific gravity; and a charging system for said cen-` trifuge comprising a mixing device, means including a conduit for delivery of said mixture to the mixing device, a conduit for a temperature-conditioning liquid in delivery connection with the mixing device, means including a conduit for passing to the mixing device separated liquid dis-l charged from the centrifuge, a main charge conduit arranged to conduct from the mixing device to the centrifuge the combined mixed charge including the said mixture, the temperature-conditioning liquid and said separated liquid, means responsive to variation in the tempera- -ture of said Vcombined charge within the main charge conduit to control delivery of the temperature-conditioning liquid through its said conduit, and means responsive to variation in delivery of said temperature-conditioning liquid through its conduit to control delivery of the separated liquid through its said conduit, to cause substantially uniform combined delivery to the centrifuge of the temperature-conditioning liquid and said separated liquid.

y2. A charging system for a centrifuge of the solid-bowl type, comprising a mixing device, means including a conduit in delivery connection with said mixing device to pass thereto a iluid mixture of materials to be separated by the centrifuge, a conduit for av temperature-conditioning liquid in delivery connection with the mixing device, a conduit for a temperature-conditioned liquid in delivery connection with the mixing device, a main' charge conduit leading from the mixing device to conduct to the centrifuge a combined mixed charge including said mixture, said temperature-conditioning liquid and said temperature-conditioned liquid, means responsive to variation in temperature of said combined charge within said main charge conduit to control delivery of the temperature-conditioning liquid through its said conduit, and means responsive to variations in delivery of the temperature-conditioning liquid through its said conduit to control delivery of the temperatureconditioned liquid through its said conduit, to

cause a substantially uniform combined delivery to the centrifuge of the temperature-conditioning liquid and the temperature-conditioned liquid.

3. A charging system for a centrifuge of the solid-bowl type, comprising a main charge conduit for delivery association with the centrifuge, means including a conduit in delivery connection with said main conduit to pass thereto a fluid mixture of materials to b e separated by the centrifuge, a conduit for a temperature-conditioning liquid in delivery connection with said main conduit, a conduit for a temperature-conditioned liquid in delivery connection with said main conduit, means responsive to variation in temperature of the combined charge of said mixture, said temperature-conditioning liquid and said temperature-conditioned liquid within the main conduit, to control delivery of the temperature-conditioning liquid through its said conduit, and means responsive to variation in delivery of the temperature-conditioning liquid through its said conduit to control delivery of the temperature-conditioned liquid through its said conduit, to cause a substantially uniform combined delivery to the centrifuge of the temperature-conditioned liquid and the temperature-conditioning liquid.

4. A charging system for a centrifuge of the y solid-bowl type. comprising a main charge conduit for delivery association with the centrifuge, means including a conduit in delivery connection with said main conduit to pass thereto a. fluid mixture of materials to be separated by the centrifuge, a conduit for a temperature-conditioning liquid in delivery connection with said main conduit, a conduit connected to the secondmentioned conduit to deliver thereto temperature-conditioned liquid for passage to the main conduit along with the temperature-conditioning liquid. an orifice device in the second-mentioned conduit and located for flow of both of said liquids therethrough, means responsive to variation in temperature of the combined charge of said -mixture, said temperature-conditioning liquid and said temperature-conditioned-liquid within the main conduit to control delivery of the temperature-conditioning liquid through its said conduit, and means responsive to variation in flow through said orifice device consequent to variation in said delivery of the temperatureconditioning liquid to control delivery of the temperature-conditioned liquid through its conduit, to cause a substantially uniform combined delivery to the centrifuge of the temperature-conticriiing liquid and the temperature-conditioned A5. Separating apparatus, comprising a centrifuge of the solid-bowl type operable to separate a charge mixture of a liquid and a lighter material and having an outlet disposed for discharge of the separated lighter material from a point spaced radially inward from the circumferential wall of the centrifuge and having also an outlet disposed for discharge of separated heavier liquid from a point radially located between said Wall and said yfirst outlet; and a charging system for said centrifuge, comprising a mixing device, a conduit in delivery connection with said device to pass the charge thereto, a conduit in delivery connection with said mixing device to conduct a temperature-conditioning liquid thereto and having a valve, a recycle conduit connection to conduct said heavier liquid discharged from the centrifuge back to the centrifuge and also having a valve, a main charge conduit forming part' of said recycle connection and arranged to conduct from the mixing device to the centrifuge the combined charge of said mixture, the temperature-conditioning liquid and the recycled liquid, a thermo-responsive device operatively connected to said valve of the conduit for the temperature-conditioning liquid and responsive tothe temperature-conditioning liquid through its conduit', a flow control device operatively connected to said valve of the recycle connection and responsive to variation in said delivery of the temperature-conditioning liquid to control delivery through the recycle connection and cause substantially uniform combined delivery to the centrifuge of the temperature-conditioning liquid and the recycled liquid for regulation of the said discharge of the separated materials.

6. Separating apparatus, comprising a centrifuge of the solid-bowl type operable to separate a charge mixture of a liquid and a lighter material and having an outlet disposed for discharge of the separated lighter material from a point spaced radially inward from the circumferential wall of the centrifuge and having also an outlet disposed for discharge of separated heavier liquid from a point radially located between said Wall and said first outlet; and a charging system for said centrifuge, comprising a main conduit for the charge in delivery connection with the centrifuge, a conduit in delivery connection with said charge conduit to conduct temperatureconditioning liquid thereto and having a valve, a recycle conduit connection arranged to conduct said heavier liquid discharged from the centrifuge back to the centrifuge and also having a valve, .a thermo-responsive device operatively connected to said valve of the conduit for the temperature-conditioning liquid and responsive to variation in temperature of the charge within the main conduit to control delivery of the temperature-conditioning liquid through its conduit, a ow control device operatively connected to said valve of the recycle connection and responsive to variation in said delivery of the temperature-conditioning liquid to control delivery through the recycle connection and cause substantially uniform combined delivery to the centrifuge of the temperature-conditioning liquid and the recycled liquid and regulation of the said discharge of the separated materials.

AUGUST HENRY SCHUTTE.

WARD F. OCONNOR..

REFERENCES CITED The following references are of record in the le of this patent:

Number u Number 10 UNITED STATES PATENTS Name Date Salenius Mar. 17, 1891 Travis Oct. 15, 1929 Walch Nov. 5, 1935 Schutte Aug. 1, 1939 Jones Mar. 11, 1941 Persoons et al. Mar. 9, 1943 Schutte Aug. 3. 1943 Schutte July 10, 1945 Schutte et a1. Feb. 5, 1946 Schutte et al. Feb. 5, 1946 FOREIGN PATENTS Country Date Great Britain Oct. 26. 1934