US2036924A - Process and apparatus for the continuous extraction or treatment of liquids - Google Patents

Description

April 7, 1936. h C CQUTOR 2,036,924-

PROCESS AND APPARATUS FOR THE CONTINUOUS EXTRACTION OR TREATMENT OF LIQUIDS Filed May 14, 1934 2 Sheets-Sheet l By: 777% ZZ/A April 7, 1936. Q CQUTQR 2,036,924

PROCESS AND APPARATUS FOR THE CONTINUOUS EXTRACTION OR TREATMENT OF LIQUIDS Filed May 14, 1934 2 Sheets-Sheet 2 Patented Apr. 7, 1936 PATENT OFFICE PROCESS AND APPARATUS FOR THE CON- TINUOUS EXTRACTION OR TREATMENT OF LIQUIDS Charles Coutor, Premery, France, assignor to Socit Etablissements Lambiotte Freres, Premery (Nievre Department), France Application May 14, 1934, Serial No. 725,630 In France May 19, 1933 7 Claims.

It is a common practice in industry to extract a definite body from a mixture constituting a liquid phase by a solvent or a reagent also liquid and non-miscible with the mixture under consideration. I

For that purpose, use is generally made of columns of the counter-current type, with or without an inner lining, or a series of mixers provided with mechanical stirrers, followed by dem canting apparatus; according to certain processes, the totality or a portion of the vapours of the solvent is used, in columns, for mixing or moving the liquids.

All these apparatus used have the inconvenience of being either of insuflicient efficiency, or difficult to carry into practice, and are costly.

The present invention has for its object a process allowing to continuously effect, by a single passage through a simple and compact apparatus, the methodical and complete extraction or treatment of a liquid by another liquid acting as solvent or reagent.

The process according to the invention is mainly characterized by the fact that the circulation and separation of the various products:

mixture to be treated, solvent or reagent, intermediate and final products, are automatically ensured by centrifugal force, which is used, for that purpose, in the following conditions:

(a) The liquids are caused to circulate on the counter-current principle, eventually in a multistage apparatus, for ensuring a methodical and complete exhaustion of the mixture.

(b) Both liquids (solvent or reagent and mixture) are simultaneously caused to enter through fixed pipes, and they are simultaneously projected on conical walls rotating at a high speed. (c) Eventually, use is made, concurrently with the movable walls, of fixed surfaces arranged very near the latter, so as to produce, by friction, a thorough stirring and intimate mixing of the liquids; this result can also be obtained by atomization, for instance under the action of the available pressure of the liquids.

(d) The centrifugal force produces the sepa-- ration of the emulsified mixture into concentric layers of different densities, viz.: into a layer comprising the solvent or reagent loaded with the body to be extracted, and into another layer 50 formed by the impoverished mixture.

(e) The bodies forming these various layers are separately drawn off by scoop-pipes similar to those of centrifugal apparatus of the so-called cream separator type, these scoop pipes con- 55 veying the various products as stated, that is to REISSUED say on the counter-current principle and through several stages in which the above operations are repeated.

When these operations are terminated, the solvent or reagent and the body it has carried along 5 are separated by any suitable process, for instance by distillation, or again by a treatment according to a process similar to that indicated above.

Of course,'for carrying out the process the principle of which has just been set forth, it is possible to provide any suitable arrangements, capable of varying in the widest limits, according to the conditions of application (nature 01' the products to be treated, of the operations to be effected, etc.) without departing thereby from the scope of the invention.

The number and variety of the possible applications of this process are in fact very extensive: for instance, and without this enumerations being in any way limitative, can be cited: the removal of tar from pyrolignous acids, removal of oil from methyl phlegms, purification of residual waters, extraction of acetic acid from its aqueous solutions, extraction of acetic acid from tars by washing with water, extraction of ethyl and methyl alcohols from their mixtures with ethers, separation of the anhydride-acetic acid mixture by petroleum, extraction of phenols, extraction of essential oils, acid or alkali treatments of petroleum on the counter-current principle, purification of oils and greases by oxidation or reduction, etc.

Likewise, any suitable plant can be devised for carrying this process into practice and especially any suitable modifications, considering the particular conditions of application, can be made in the dimensions of the apparatus, arrangement of the scoop-pipes, number of stages-or oi successive treatments, etc.

In certain cases it may be desirable or possible, considering the complexity of the mixture, to discern more than two concentric layers capable of being simultaneously separated; additional scoop-pipes and partitions can then be provided and suitably arranged.

Concerning that point, one may be led to draw off, in the form of sludge, a precipitate the density of which will be comprised between those of both liquids.

Likewise, one may be led to use as reagent a pulverulent product practically behaving as a liquid in the various partitions of the apparatus, but, in this case, the scoop-pipes and mixing devices will of course be modified. This will be done every time a liquid will be treated by a carbon or discolouring earth for instance.

Furthermore, use can be made, without departing from the invention, of .a centrifugal apparatus rotating about an axis of orientation, the liquids can be introduced in said apparatus after previous cooling or reheating, and, consequently, the apparatus can be heat insulated or heated, the operation can be effected in presence of any gas, under vacuum or under pressure, etc.

By way of example, and in order that the invention may be more clearly understood, a form of construction of such an apparatus will be described hereinafter with reference to the accompanying drawings, this apparatus being adapted to be used for the extraction of a body dissolved in water, by means of a light solvent.

Figure 1 is an axial vertical section of the entire apparatus.

Fig. 1 is a cross section made according to broken line V-V of Fig. 1.

Fig. 1 is a partial section, on an enlarged scale, made according to line 2-2 of Fig. 1

Figure 2 is a similar partial view of a modificacation.

This apparatus comprises a turbine body I, capable of receiving a rapid movement of rotation from a suitable motor (not shown), for instance through the medium of a transmission comprising a belt, a pulley 2 and a shaft 3.

This turbine rotates about a fixed hollow shaft 4 which passes through one end thereof, preferably through a hydraulic joint 5 ensuring fluidtightness. r

The shaft contains the inlet and outlet conduits for the products, via: a conduit 6 through which is admitted the mixture to be treated and a conduit 1 through which is admitted the solvent or reagent, a conduit 8 through which is discharged the exhausted mixture, and a conduit 9 through which is discharged the solvent or reagent loaded with the extracted product. The arrows in full lines indicate the mixture and the arrows in broken lines, the solvent or reagent.

The body I is divided into six juxtaposed compartments C1 C2 C6 by five annular partitions N1 N2 N5, and in each of these compartments are arranged two other annular partitions L1 M1, L2 M2 L6 M6, respectively; the partitions M1 to Ms have an outer diameter smaller than the inner diameter of the body I and the partitions L1 to L6 have a diameter smaller than that of the partitions M1 to Ms. These partitions are arranged as follows:

The partition M1 M6 (each partition bears indicia of the compartment to the left of which it is located in Fig. 1) is arranged at right angles to the axis of the turbine, so that a passageway m1 ms is provided between its outer edge and the wall of the body I.

To the right of the preceding one, is a partition L1 LG having a central frustumshaped portion and the outer edge of which is offset relatively to that of m1 Me so as to also provide a peripheral passageway 11 ls.

Finally, to the left of each of the partitions M1 M5, is a third partition N1 N5 secured to the inner wall of the body I.

Free narrow spaces D1 De exist between the partitions L, M and other narrow spaces E1 E5 are provided between the partitions M, N.

The decanting compartments alone are relativedly large.

The circulation of the products takes place moreover through fixed tubes, arranged in the following manner:

The solution is led through compartments C1 Ca from right to left on the drawing through scoop-pipes f1 f5 one end of which opens in the space comprised between the two partitions M, N and having an extension constituted by a conduit 02, 0a Os terminating in an annular jet b2 be opening very near the frustum-shaped portion of the corresponding wall L2 Le.

On the other hand, the solvent or reagent flows through the compartments Cs C1 from left to right on the drawing through scoop-pipes C6, 05, c4, 0: which extend from the compartment bearing the same indicia and leads to the annular jet b bearing a lower indicia.

The inlet ends of the scoop-pipes are so arranged that the liquids enter therein by inertia.

The conduit 6 through which is admitted the solution terminates in a conduit 01 and an annular jet b1 opening in proximity to the wall L1 and to which leads the scoop-pipe C2; the ends of these pipes extend through a relatively important arc of the circumference of the apparatus as diagrammatically indicated in Fig. 1 The distance separating the fixed and movable surfaces is so adjusted as to ensure satisfactory emulsion of the solution and solvent.

The discharge conduit 9 for the extracted product is fed by a scoop-pipe 01 opening in the compartment C1.

The inlet conduit 1 for the solvent or reagent opens in the last annular jet be.

Finally, the discharge conduit 8 for the exhausted solution extends down, in the compartment Ce, beyond the last partition L6.

The operation is as follows:

The solution to be treated, admitted through 6 and O1, is projected by the jet b1 on'the frustumshaped portion of the wall L1, at the same time as the solvent or reagent which has already passed through the five compartments Cc C: and is led to this jet b1 by the scoop-pipe on.

Both liquids, intimately mixed, thus enter the mixing space or chamber D1 in which the exhaustion of the solution begins.

These liquids are subjected to the action of centrifugal force and, owing to their difference of density and of their non-miscibility, they separate and form two concentric annular layers P1, P2, the outer layer P1 being formed by the solution, which is the heavier, and the inner layer P2 by the solvent.

The separating surface X-X of the two layers reaches, during the rotation, a level which depends on the radial distance separating the inlet ends of the scoop pipes 01 and f1, cn and la, etc., and on the density of the liquids treated, and this radial distance is so adjusted that in each compartment the said surface of separation X X is located at a distance from the axis of rotation at most equal to the radius of the respective disc L1 or L2 and however large enough in order that the layer of solvent comprised between the level X X and the level Y Y of the inlet ends of the solvent scoop pipes c1 02 should have a sufficient thickness.

The solvent of the layer P2 is drawn off through the scoop-pipe c1 and discharged through the conduit 9, whilst the solution, passing through m1 and E1 is drawn off through the jet f1 and sent, through 02, be into the compartment 0:.

accesseat the same time as the solvent coming from the compartment C3 passes through the scoop-pipe 03.

The exhaustion thus progressively proceeds in the various compartmehts through which pass, on the one hand, the solution and, on the other hand, the solvent or reagent, according to the counter-current principle.

According to the modification illustrated in Fig. 2 each space D is supplied with a mixture of solvent and solution through a double jet having two concentric orifices: the inner jet serves for the admission of the solution, which is sent to it from one compartment by a scooppipe 1, and the outer jet serves for the admission of the solvent, which is sent to it from the next compartment through a scoop pipe 0.

I claim:

1. An apparatus for removing at least one of the constituents from a liquid mixture by centrifugation of the mixture and scooping the separate liquid layers, comprising a drum rotatively mounted and laterally bounded by two annular discs, arranged for forming with the drum an inner annular compartment, means for causing this drum to rotate at a high speed, two annular discs secured within this drum and arranged for dividing said annular compartment into a lateral space of great width, a narrow intermediate space and a narrow lateral space, the disc limiting the narrow lateral space extending outwardly to a small distance from the periphery of the drum, and the disc separating the intermediate space from the space of great width extending outwardly to a greater distance from the periphery of said drum, a fixed nozzle opening at the inner periphery of said drum, in the intermediate space and directed towards the annular disc separating this space from the space of greatvwidth, a supply piping opening in this nozzle and adapted to lead from the exterior the mixture of liquids to be treated, a supply piping also opening in. this nozzle and adapted to convey the solvent in the latter, a scoop-pipe extending from the lateral space of great width and adapted to evacuate the solvent laden with the constituent to be removed from the mixture, and a scoop-pipe extending from the narrow lateral space and adapted to evacuate the treated and exhausted mixture.

2. An apparatus for removing at least one of the constituents from a liquid mixture as claimed in claim 1, in which the inner peripheral portion of the disc separating the intermediate space from the space of great width, has a portion in the shape of a. conical surface.

3. An apparatus for removing at least one of the constituents from a liquid mixture, as claimed in claim 1, in which the outlet orifice of said nozzle opens against the portion in the shape of a conical surface separating the intermediate space from the space of great width, said orifice being very close to said conical surface.

4. An apparatus for removing at least one 01 the constituents from a liquid mixture, as claimed in claim 1, in which the end of the scoop-pipe extending from the lateral space of great width and the end of the scoop-pipe extending from the narrow lateral space, are directed in a direction reverse to the direction of rotation of the drum.

5. An apparatus operating on the countercurrent principle for removing at least one of the constituents from a liquid mixture as claimed in claim It, in which the drum is internally divided into a series of annular compartments, each of which is divided into a lateral space of great width, a narrow intermediate space and a narrow lateral space, and has a nozzle within each intermediate space, the piping adapted to convey the mixture of liquids to be treated opening in the last nozzle at one of the ends of the drum, the piping adapted to convey the solvent opening in the last nozzle at the other end of the drum, the narrow lateral space of each compartment being connected to the nozzle of the following compartment, relatively to the direction of circulation of the mixture being treated, by a scoop-pipe, and the space of great width of each compartment being connected to the nozzle of the following compartment, relatively to the direction of circulation of the solvent, by another scoop-pipe.

6. A method for extracting a body from a complex liquid mixture by means of an auxiliary body acting as solvent or reagent on said body to be extracted, this auxiliary body being liquid and nonmiscible with the liquid mixture to be treated, said method consisting in introducing together the liquid mixture to be treated and the auxiliary body into a rotary vessel where they come in intimate contact, then separate in the form of concentric layers under the influence of centrifugal force, one of the layers being especially constituted by the auxiliary body and that of the liquid bodies it has lved, and the other layer being especially cons ituted by the impoverished liquid mixture, and in continuously extracting from each oi these layers the portion situated nearest the axis of rotation by a scooping operation.

7. A method for extracting a body from a complex liquid mixture by means of an auxiliary body acting as solvent or reagent on said body to be extracted, this auxiliary body being liquid and nonmiscible with the liquid mixture to be treated, said method consisting in introducing together the liquid mixture to be treated and the auxiliary body into a rotary vessel where they come in intimate contact, then separate in the form of concentric layers under the influence of centrifugal force, one of the layers being especially constituted by the auxiliary body and that of the liquid bodies it has dissolved, and the other layer being especially constituted by the impoverished liquid mixture, in continuously extracting from each of these layers the portion situated nearest the axis of rotation by a scooping operation, and in discharging the liquids thus extracted respectively in two other rotary vessels where they again separate in the form of concentric layers and so on, so that the solution circulates in one direction and is consequently enriched with the body to be extracted, and the impoverished liq uid mixture insoluble in the auxiliary body circulates in the reverse direction and is consequently purified, the evacuation and transfer of the liquids from one vessel to another being always produced by scooping out from portions of said liquid layers situated the nearest to the axis of rotation.

COUTOR, CHARLES.

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