US1974698A - Rotary apparatus for resolving emulsions - Google Patents

Description

Sept. 25, 1934. w V LoENEN 1,974,698

ROTARY APPARATUS FOR RESOLVING EMULSIONS Filed March 18, 1933 2 Sheets-Sheet 1 L519 -d 3 I6 FIG. 2

ILLIAM F. VAN LOENEN INVENTOR Sept. 25, 1934.

W. F. VAN LOENEN ROTARY APPARATUS FOR RESOLVING EMULSIONS Filed March 18 1933 2 Sheets-Sheet 2 a9 Hhs/ EMULSION WILLIAM E VAN LOENEN Patented Sept. 25, 1934 NETE STATfi FFICE ROTARY APPARATUS FOR RESOLVING EMULSIONS William F. Van Loenen, Buena Park, Calif., as-

' signer to L. Blake-Smith, San Francisco,

The object of my invention is to provide an apparatus and an operating method for the treatment of petroleum and other emulsions with granular solids.

In an application filed May 21, 1932 by Charles J. Robinson a process of treating emulsions is set forth, this process consisting substantially in passing through a body of the emulsion grains of a solid substance having a superior superficial attraction for the dispersed phase of the emulsion, these grains being projected downwardly and being materially heavier than water in cases Where water constitutes the dispersed phase of the emulsion, or being materially lighter than oil and being projected upwardly in cases where oil is the dispersed phase.

In an application filed by me on May 21, 1932 under Serial No. 612,847 I have described and claimed an apparatus suitable for applying these solid reagents to emulsions, this apparatus bearing a material resemblance to that set forth in the instant application.

In the practical application of the process described in the Robinson application 612,855 it was discovered that the operation could be greatly facilitated and its results improved by maintaining in the treating vessel a more or less constant and relatively large quantity of a treating solid ranging in size from 12-mesh up to as large as /2 inch, together with a controlled and relatively small quantity of a treating solid comminuted to IOO-mesh and finer, and consisting in part of particles of extreme fineness, approaching a colloidal condition. These discoveries and a treating method based thereon are fully disclosed and claimed in an application filed by Charles J. Robinson on March 18, 1933 under Serial No. 661,586,,and not being a part of the present invention are not further described except in so far as they reflect on the apparatus and method herein described.

The apparatus described in my copending application consisted essentially of a horizontally arranged cylinder, provided with internally projecting vanes and arranged to revolve about its horizontal axis. A centrally arranged inlet pipe passing through a stufiing box in the end of the cylinder provided for a continuous feed of the emulsion to be treated while a centrally arranged outlet pipe provided for the separate withdrawal of oil from the upper part of the cylinder an of Water from its lower portion.

In this apparatus the Robinson treating agent, which for the treatment of the typical crude oil emulsion of the water-in-oil type is a rela- 1933, Serial No. 661,517

tively heavy, hard, insoluble and chemically inert material which acts on the emulsion by reason of its superior attraction for the particles of the dispersed liquid, is lifted from the bottom of the treating vessel in the pockets formed by the juncture of the internal vanes with the shell, and is poured back into or on the upper surface of the body of liquid in the shell, passing through it to the bottom of the vessel to be again picked up and returned. In this apparatus the water which separates from the emulsion forms a lower layer, the unbroken emulsion an intermediate layer, and the separated oil an upper layer within the rotating vessel, which is revolved at such relatively low speed as not to prevent a consistent Stratification.

When the Robinson process, as originally described, was modified by the introduction of a material quantity of finely divided solid material, an entirely new set of conditions was set up, under which my original apparatus did not function in a satisfactory manner. I found that the large grains, 12-mesh and coarser, were sufliciently heavy to rapidly settle through the mass of oil, water and emulsion and collect on the bottom of the vessel but that the fine particles settled so much more slowly that there'was a constant efiiux of fine treating agent from the apparatus in the form of water droplets suspended in the discharged oil and themselves containing suspended fine solid particles. I also found that with the accelerated rate of resolution produced by the addition of the fine agent, it was permissible and desirable both to revolve the apparatus and to supply crude emulsion at such speeds as to prevent a complete stratification of oil, unbroken emulsion, and water in the apparatus, and that it was desirable to continuously withdraw a mixed stream of resolution products consisting of oil, water, and fine treating agent suspended in the water drops, and to separate the Water from the oil in a separate and stationary vessel.

I also found that at these high rates of revolution and of feed, there was a strong tendency for at least the finer portion of the coarsely comminuted agent to be carried out of the treating vessel.

The improvements herein described relate, first, to methods directed to retain in the treating vessel all solid particles which are of sumcient size and weight to subside to the bottom of the vessel and to prevent their being carried away by the agitation set up in the vessel and by the velocity of the liquid passing therethrough;

second, to means for separating the resolution products into a layer of oil substantially free from water and a layer of water entirely free from oil but containing suspended fine solids, and for separating the solids from the water in such condition as to permit their return to the treating vessel; third, to means for returning the fine solids, or such proportion of them as may be required, to the treating vessel, in or to maintain in the treating vessel the quantity or proportion of fine solids required for the resolution of the emulsion at the most rapid rate.

These means and methods will be described in connection with the attached drawings in which, Fig. l is a vertical cross section and interior elevation of a treating vessel including certain means for preventing relatively coarse solids from being carried out of the treater;

Fig. 2 is a similar section and elevation illustrating certain modified means to the same end;

Fig. 3 is a cross section and internal elevation as on the line 3-3 of Fig. 1;

Fig. 1 is a cross section and internal elevation as on the line 4- 1 of Fig. 1;

Fig. 5 is a similar section and elevation as on the line 55 of Fig. 1, and

Fig. 6 is an assembly of the entire apparatus, certain hidden parts being indicated by dotted lines.

Referring first to Fig. 6, a complete treating plant consists of five individual units as illus trated, A being any pure B a heating means, C a rotating treating vessel, Da water and slime settling vessel, and E a preferred means for returning slime to the treater. Throughout the following description the term fines will be used to denote the finely ground treating agent, substantially finer than 100-mesh and the term slime will beunderstood as referringto a suspension of the finely comininuted treating solid in water.

Having reference to the directional arrows shown in Fig. 6, the operation of the plant may be summarized as follows:

7 The pump A draws emulsion from a source of supply not shown through a pipe 61 and discharges it through a pipe 62 into the heater B. This heater may be of any preferred type, the one indicated in the drawing being that well known form in which oil passes through the shell around a nest of tubes through which steam is passed. The pump is supplied with steam through a pipe 63, the exhaust passing through pipe 64 into the heater, from which condensed water is withdrawn through the pipe 65. The heated oil, the temperature of which may be observed on a thermometer 66, passes into the treating assembly 0 through a pipe 67.

. The'treating assembly consists of a treating vessel-'68 which may be supported on trunnions 69 and revolved in any convenient manner, as, for example, by means of an electric motor 610 driving a ring gear 611 through a pinion 612. The internal construction and the method of opera tion of this treating vessel will be described in connection with other figures. A mixture of treatedor demulsified oil with water and fines is discharged from the treater through a pipe 613 into the'water settling unit 13. Pipes 6'7 and 613 a-restationary'and stufiing boxes 614 and 615 are provided wherethese pipes enter and leave the treating vessel.

The water settling unit D consists first of a closed tank or hollow'shell 616 which is preferably set on-an .angle'of about as shown. This tank is provided at its uppermost point with an outlet pipe 617 for treated oil, and in some cases it is desirable to place in this pipe a manual or automatic pressure relief valve 618 for the purpose of maintaining a moderate pressure on the system. The tank is also provided along its side with a row of test cocks 619 for determining the approximate parting line between water and oil within the tank. A gauge glass may be substituted for these test cocks but usually does not operate very satisfactorily as it rapidly accumulates a coating of oil which obscures the reading.

A pipe 620 controlled by a manual valve or stop cock 621 provides for the withdrawal of water from the settling tank at such rate as to maintain a desired parting level therein. This pipe is preferably extended inside the tank to form a swing pipe622 by means of which water may be withdrawn from a higher or lower level as preferred, as indicated by the are 623. The tank is also provided at substantially its lowermost point with an outlet pipe 624 controlled by a valve 625, preferably of the well-known quick-closing type, through which slime may be withdrawn as required.

The mixture of oil, water, and fines leaving the treater flows through pipe 613 into the top of the tank 616 as shown and immediately separates, oil passing into the upper part of the vessel while water carrying fines in suspension remains in the lower part of the vessel. At the same time a second separation takes place, the fines gravitating downwardly through the water layer to form a thickly fiuid slime in its lowermost part. The oil layer, moving very slowly upwardly toward the outlet 617, has time. to deposit any suspended Water; so that oil substantially free from water may be withdrawn through this pipe to a point of storage .or'other disposition not shown. The height of the swing pipe 622 is so adjusted as to withdraw water free from fines, this water passing through the pipe 620 to any point of disposition of waste water.

As fully set forth in the Robinson specification, filed March 18, 1933, it is necessary, in order to obtain the best results in the application of that invention, to so regulate and control the quantity of fines in the treating vessel as to maintain the mass just short of that point at which the direction of the emulsion begins to reverse, that is to say, at the point where the resolution product from a water-in-oil emulsion begins to show traces of oilin-water emulsion. By mutual abrasion of the solid grains in the treater during the continual tumbling to which they are subjected, an added quantity of fines is constantly being produced, and for this reason fines tend to accumulate in the system. The rate at which fines are produced, however, is very much less than that at which they are carried out of the treating vessel into the water-settling tank and it is therefore necessary to constantly return to the treating vessel a large proportion of the fines which are carried away from it and to Withdraw from the system, continuously or at reasonable intervals,

they are suspended and to form obstructions at 1.59

iii

any point where the slime is allowed to come to rest.

I have therefore provided the transfer system generally indicated at E in Fig.6 which includes, in duplicate, the following elements:

A transfer tank 626 has a conical bottom, the point of which communicates with pipe 624 through a branch pipe 627 controlled by a manual valve 628. Between the point of the cone and the valve 628 is a communicating pipe 629 controlled by a stop valve 630, the pipe 629 being branched from an air-supply pipe 631 which is controlled by needle valve 632. Pipe 631 communicates with any source of supply of air under pressure,'not shown.

Through the top of the transfer tank 626 I pass a discharge pipe 633 controlled by a stop valve 634, these pipes being carried to a point close to the bottom of the transfer tank but somewhat ofif center. The two pipes 633 communicate with a single pipe 635 through which a connection is made with the emulsion inlet pipe 67, thus establishing communication between the transfer tank and the interior of the treating vessel 68.

In the operation of this device the transfer tanks are used alternately, one being filled while the other is being emptied. In order .to fill the tank air stop valve 630 is closed, valve 628 is open, as is also valve 625, valve 63 i being closed. The test cock 636 is then opened to release the air pressure within the transfer tank, whereupon the pressure existing within the water settling tank 616, due either to hydrostatic head or to the resistance of the relief valve 618, displaces shine from the lowermost part of the settling tank and fills the transfer tank 626.

When slime shows at the test cock 636, indicating that the transfer tank is full, valve 628 and test cock 636 are closed and Valves 634 and 630 are opened. A minute stream of compressed air, which is regulated in advance at needle valve 632, now enters pipe 627 immediately above valve 628 and rises through the slime in .the vessel, keeping it in agitation and preventing it from stratifying. The accumulation of air in the upper portion of the vessel places a pressure on top of the slime by which it is forced through the pipes 633 and 635 and into the treating vessel, as already described, at a rate which is substantially constant and which may be varied by controlling the amount of air passing through valve 632. When the transfer tank is substantially empty, as may be determined by occasionally opening the test cock 637 or by viewing the stream of slime passing through a conventional look-box 636, the duplicate tank may be brought into service, this tank having been filled while its mate was being emptied.

This shift from tank to tank may be made at such intervals that no material stratification of the slime in the tank which is not in use will take place, though it is desirable not to fill the empty tank until just before it is to be put into service. If a slight amount of stratification takes place, the contents of the tank will soon be brought back to uniform consistency by the passage of a stream of air into the bottom of the tank. It has been found by experience that this method of transferring produces a substantially uniform flow of the slime from the transfer tank into the treating vessel and that the described method of controlling the return of slime by means of control of the actuating air is much more satisfactory than any attempt to throttle the fiow of the slime iself, its characteristics being such that it is practically impossible to prevent any'tln'ottling valve from bridging over.

While I have shown a pair of transfer tanks and arrangement for using them in alternation, it should be said that it is possible to operate in a very satisfactory manner with a single transfer tank as described, theinterruption to the return of fines occasioned by the refilling of the tank being very brief. Where there is reasonable hydrostatic head or back pressure on the settling tank, the time required to refill the transfer tank should not exceed one minute, while the time required to empty it will vary from an hour to several hours, according to the relation between the size of this tank and the size of the treating vessel.

On account of the relative rapidity with which the fines are carried out of the treating vessel, it it necessary that their reurn should be substantially though not necessarily entirely constant. On the other hand, the quantity of fines existing in the system as a whole is immaterial, only the fines which are in the treating vessel itself and in contact with emulsion being subject to close control. For this reason the lower portion of the water-settling vessel is available as a storage leeway space for slime and the withdrawal of any excess quantity, as indicated by the occurrence of slime or solid sediment in the water withdrawn through pipe 620, may be made at any convenient interval. For this purpose I have provided a drain pipe 638b-controlled by a manual valve 639, this pipe leading to any sump or other place of disposal of solid sediment.

Referring now to Figs. 1 to 5 inclusive, the treating vessel 68 is provided witha plurality of longitudinal vanes 16 and is arranged to rotate in the direction indicated by the arrow at the top of Fig. 3. These vanes, as already stated, form pockets in which the grains of heavy and coarse treating agent collect'and by which they are carried to the upper portion of the vessel and discharged in or out to the liquid therein to return through the emulsion to the bottom of the vessel.

Emulsion enters therotor 68 through the fixed pipe 67 passing through the stuffing box 61 i and the resolution products are di charged through the pipe 613 passing through the stufiing box 615. The pipe 613 may desirably have interposed in its length a stufiing box or slip joint 13 and be provided with a T handle 14 by means of which the interior pipes 11 and 12 be fixed at different levels and in different angular positions, as indicated at 12a and 12b in Fig. 5. I have found that there is much less tendency for the solid treating agent to be carried out of the rotor when the outlet pipe is in substantially the position indicated by 120., that is to say, on the falling instead of the rising side of the rotor.

The vanes 10 do not extend for the entire length of the rotor but are interrupted close to the plane of a baffle plate 15 which is placed in a position transverse to the axis of rotation and is so supported as to revolve with the shell as, for

instance, by the arm 16 indicated in Fig. 4. This baffle plate does not extend to the inner surface of the shell but is of such smaller diameter as to leave an annular opening 17 for the free passage of liquid from the treating portion 18 of the rotor to the settling portion 19.

This annular space should be as narrow as is consistent with the passage into the treating portion of any coarse solid which may settle in the settling portion as, for instance, it may be from one inch to two inches in width.

" it may be desirable to raise the level of v The purpose of this baflie plate is to-provide a settling space or a zone of quiescence in free communication with the treating space of the shell of the rotor but protected from the convection currents set up by the rotation. Quiescence in the space 19 may also be promoted by the use of a second bafile plate 20 projected from thepipe 12. This zone of quiescence has been found to be extremely effective in preventing the passage of coarse solids out of the rotor with the mixture of oil and water which is withdrawn through pipe 613.

With the arrangement of pipes shown, the upward projection 11 establishes the upper level of liquid in the shell while the downwardly projected pipe 12 establishes a parting line between oil and water, which separate in the zone of quiescence. The level of this parting line may be varied by varying the angular position of the pipe 12 as shown in Fig. 5. Where the emulsion belng treated contains a large proportion of water, it is often desirable to maintain the parting line at a low level, while if the emulsion being treated contains a smaller proportion of water,

the parting plane.

In the operation of the device as so far described there is a constantly operating tendency for coarse mineral to be carried through the annular opening 17 and to be deposited in the settling space 19. To counteract this tendency and to return such solids to the treating space in the rotor I make three provisions, two of which are alternative while the third may be utilized with either.

Referring to Fig. 1, I attach tothe interior of the shell within the settling space 19 a helical rib 21. which is of slight height, say inch, the turns being spaced say 4 to 6 inches. This rib in effect constitutes an internal'screw conveyor by'which solids riding up the rising side of the rotor and constantly slipping back are gradually returned to and through the annular space 17 to the treating end of .the vessel. An alternative provision is the cone 22 shown in Fig. 2 which operates in substantially the same manner, the solid sliding downhill to the wider portion of the cone. In connection with either of these'devices I prefer to bend that end of the vanes 10 which approaches the bafile 15, in the direction in which the vanes rise as the treater revolves, as indicated at 23 in Fig. 2. The slope away from the bafile on the rising side of the rotor which is thus produced may be quite slight, as, for instance, one inch to two inches per foot of length, but it has a strong tendency to move the solids away from the portion of the treating space immediately adjacent the baffle, to allow room for solids deposited in the settling space to be returned beneath the bafiie.

By the use of the various devices and provisions herein described I am enabled to treat emulsion with either the solids described in the Robinson application or any other suitable solids, at any rate of rotation and of feed which may be found most advantageous, by retaining in the treating vessel all of the coarse solids and by returning to it all of the fines, or such proportion thereof as may be required to maintain the treatment at its point of highest efficiency.

1 claim as my invention:

1. Apparatus for treating emulsions with comminuted insoluble solids: means for continuously intermixing said solids with a liquid body of said emulsion whereby resolution thereof is effected;

means for introducing to said body a flow, stream of said emulsion; means for withdrawing from said body a flow streamcomprising oil, water and a portion of said solids; means for separating and for withdrawing oil from last said flow stream; means for separating and for withdrawing water from said solids, and means for measuring and for returning a desired portion of said solids to said body.

2. Apparatus for treating emulsions with in soluble solids comminuted in part to a coarse grain and in part to a fine grain: means for continuously intermixing said solids with a liquid body of said emulsion whereby resolution thereof is effected; means for introducing to said body a flow stream of said emulsion; means for withdrawing from said body a flow stream comprising oil,-water and a portion of said fine solids; means for substantially retaining said coarse solids in said liquid body; means for separating and for withdrawing oil from last said flow stream; means for separating and for withdrawing water from said fine solids, and means for measuring and for returning a desired portion of said fine solids to said body.

3. Apparatus for treating emulsions with comminuted insoluble solids: a horizontally rotating treating vessel provided with lifting and mixing vanes; means for introducing a flow stream of emulsion into said vessel; means for withdrawing a flow stream of oil, water and solids from said vessel; a second vessel wherein last said stream may separate into layers of oil, Water and aqueous suspension of said solids; means for withdrawing oil and water from said. second vessel; means for withdrawing said suspension from said second vessel and means for measuring and for returning a desired portion thereof to said rotating vessel.

' 4. Apparatus for treating emulsions with insoluble solids comminuted in part to a coarse grain and in part to a fine grain: a horizontally rotating treating vessel provided with lifting and mixing vanes; means for introducing a fiow stream of emulsion into said vessel; means for Withdrawing a flow stream of oil, water and said fine solids from said vessel; baflies within said vessel for substantially preventing the withdrawal of said coarse solids while permitting said fine solids to be withdrawn with said last flow stream;

a second vessel wherein last said stream may separate into layers of oil, water and aqueous suspension of said fine solids; means for withdrawing oil and water from said second vessel, and means for withdrawing said suspension from said second vessel, and means for measuring and for returning a desired portion thereof to said rotating vessel.

5. A method of resolving emulsions which coinprises: intermixing with a liquid body of said emulsion granular insoluble solids having the property of resolving said emulsion into its constituents; continuously introducing emulsion into said body; continuously withdrawing from said body a flow stream of said resolved constituents carrying finer portions of said granular solids produced by abrasion of the original grains thereof; substantially separating said finer solids from said products; returning a sufficient portion of said solids to said body to maintain a substantially constant proportion of said finer solids in said body, and discarding the remainder of said finer solids.

6. A method of resolving emulsions which comprises: intermixing with a liquid body of said emulsion granular insoluble solids having the property of resolving said emulsion into its constituents; continuously introducing emulsion into said body; continuously Withdrawing from said body a flow stream of said resolved constituents carrying finer portions of said granular solids produced by abrasion of the original grains thereof; substantially separating said withdrawn solids from said products, measuring and returning a desired quantity of said separated solids to said body, the portion so returned being less than the quantity withdrawn with said flow stream, and discarding the remainder of said separated solids.

'7. A method of resolving emulsions which comprises: interrnixing with a liquid body of said emulsion insoluble solids comminuted in part to a coarse grain and in part to a fine grain; continuously introducing emulsion to said body; continuously withdrawing from said body a fiow stream of said resolved constituents carrying portions of said fine solids while substantially retaining said coarse solid Within said body; substantially separating said fine solids from said constituents; returning a sufiicient portion of said separated solids to said body to maintain a substantially constant proportion of said fine solids in said body, and discarding the remainder of the separated solids.

8. A method of treating emulsions with granular insoluble solids having the property of resolving said emulsien into its constituents: maintaining in an agitating zone a mixture of said emulsion with said solids; continuously transferring portions of said mixture to a zone of relative quiescence in which coarser particles of said solids may separate from said resolved constituents by a gravity effect; continuously returning said particles to said agitating zone; continuously transferring said constituents together with finer solid particles to a settling zone; substantially separating said finer particles from said constituents; returning a sufficient portion of said finer particles to said agitating zone to maintain therein a substantially constant proportion of said finer particles, and discarding a quantity of said finer particles substantially equal to the quantity of finer particles produced by abrasion of the original granules in said agitating zone.

WILLIAM F. VAN LOENEN.

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