US3239315A - Apparatus for contacting two liquids of different specific weights - Google Patents

Description

March 8, 1966 J. A. DE SMET 3,239,315

APPARATUS FOR CONTACTING TWO LIQUIDS 0F DIFFERENT SPECIFIC WEIGHTS Filed Jan. 5, 1965 2 sheets-{sheet 1 F/Gi I I 4? f I E 3-- i 47 24 i i IS a a i 50 g 48 I a E/ i t I l7 4 I I 5 A INVENTOR JEAN ALBERT DE SMET BY ewqlk ATTORNEYS J. A. DE SMET APPARATUS FOR CONTACTING TWO LIQUIDS OF DIFFERENT SPECIFIC WEIGHTS March 8, 1966 2 Sheets-Sheet 2 Filed Jan. 5, 1965 m m m JEAN ALBERT DE SMET 0 BY mm M b \Mk ATTORNEYS United States Patent 3,239,315 APPARATUS FOR CGNTACTING TWO LIQUIDS OF DIFFERENT SPECIFIC WEIGHTS Jean Albert De Smet, Wilrijk, Belgium, assignor to Extraction De Smet, Edegem, Belgium, a Belgian company Filed Jan. 5, 1965, Ser. No. 423,432 Claims priority, application: Luxembourg, Feb. 18, 1960, 38,262; Dec. 29, 1964, 47,690 2 Claims. (Cl. 23-2705) overall counter-current procedure is carried out.' The" procedure comprises a series of operations of intimate mixing of two liquids within a series of compartments, each mixing operation being followed by a decantation operation. While, when viewed overall, the procedure is counter-current, the two liquids move in the same direction through each of the compartments involved in the apparatus.

The apparatus according to the invention may be utilized to provide contact between two liquids of different specific weights so as to provide a process of solvent extraction. The apparatus comprises a vessel having a series of compartments extending in longitudinal direction and delimited by substantially parallel and horizontal plates. The vessel has four substantially vertical walls, two of said walls extending in longitudinal direction, the two others extending in transverse direction. The plates extend to the longitudinal walls and to a point which is some distance from the transverse walls so as to leave a passage permitting liquid flow between the transverse edges of the plates and the transversal walls. The lower compartment and the upper compartment have a discharge opening. The compartment which is situated immediately above the lower compartment as well as the compartment which is situtated inunediately below the upper compartment has an inlet opening. Each of the intermediate compartments contains a means for mixing the liquids and for propelling the mixture through the compartment. Said means are alternately arranged on one side and on the other side of the adjacent compartment. The mixing and propelling means of the compartment which is immediately above the lower compartment is situated on the same side as the inlet opening of said compartment and the mixing and propelling means of the compartment which is immediately below the upper compartment is situtated on the same side as the inlet opening of said compartment.

In an advantageous embodiment of the invention, the apparatus contains a bafiie means for each of the intermediate compartments comprising a horizontal partition extending in transverse direction, which is connected to the transverse wall on the same side as the mixing and propelling 'means and which extends into the compartment for a distance which is less than the distance from the transverse wall to the mixing and propelling means.

In a particular embodiment of the invention, the mixing and propelling means are comprised of shafts extending in transverse direction and having blades arranged in planes comprising the geometrical axis of the shaft.

In an especially preferred embodiment of the invention, the shaft is arranged in a chamber delimited by two vertical walls extending the Whole height of the compartment 3,239,315 Patented Mar. 8, 1966 and having a median slot extending in transverse direction, the portion of the wall which is provided on the compartment side and below the slot being offset towards the compartment with respect to the upper part of the same wall and having a flange which is bent towards the shaft.

Other details and particularities of the invention will be apparent from the description of an apparatus according to the invention, the description which is given being solely by way of non-limitative example and with reference to annexed drawings.

FIG. 1 is a diagrammatic vertical section of an apparatus according to the invention.

FIG. 2 is a section along line 22 of FIG. 1.

FIG. 3 is a section along line 33 of FIG. 2.

In the various figures, the same reference numerals relate to identical elements.

The apparatus shown in the figures is intended to contact two liquids of different specific weights, so as to carry out a procedure of solvent extraction. While the apparatus can be employed in any case wherein an extracting liquid is used to extract some material from a conveying liquid, the apparatus will be described with reference to the figures in connection with the extraction of soaps from a miscella by means of an alcohol. In the method of particular use of the apparatus, described by way of example, the conveying liquid is comprised of misceila, for example of an oil or grease solution in hexane. This miscella also contains soaps which must be extracted. The material to be extracted thus comprises soaps, while the extracting liquid comprises dilute alcohol.

The apparatus comprises a vessel made up of a lower wall 1 which forms the bottom, an upper wall 2, two transverse walls 3 and 4 and two longitudinal walls 5 and 6. The vessel is divided into compartments by horizontal plates 7 to 15. In FIG. 1, nine horizontal plates are shown but it has to be understood that in practice the plant will generally comprise a larger number of plates. Said plates are closely arranged, the distance between two adjacent plates being from 50 millimeters (mm.) to about mm. The distance between the lower wall 1 of the vessel and the lower plate 7 is also about 50 mm. to 100 mm. Also the distance between the upper plate 15 and the upper wall 2 of the vessel is about 50 to 100 mm. Each of the plates 7 to 15 extends to the longitudinal walls 5 and 6, as may be seen from FIG. 2. Each of the plates 7 to 15 extends only to a point some distance from the transverse walls 3 and 4. This may be seen in FIG. 1. Between the transverse walls 3 and 4- of the vessel and the transverse edges of the plates 7 to '15, i.e. the edges of said plates which are parallel to the transverse walls 3 and 4, a passage remains free for the flow of the liquids. Each of the intermediate plates, i.e. plates 8 to 14, has at one end a downwardly oriented flange 16 and at the other end an upwardly oriented flange 17. This flange 17 is opposite to a downwardly orientated flange 16 of an adjacent plate. The sum of the heights of the flanges 16 and 17 is substantially less than the distance between two adjacent plates, so that a passage remains free between opposite flanges of adjacent plates.

The lower plate 7 has only an upwardly orientated flange 18 opposite the downwardly orientated flange 16 of the plate 8. The upper plate 15 has only a downwardly orientated flange 19 opposite the upwardly orientated flange 17 of the plate 14. Furthermore, the plate 15 extends to the transverse Wall 4, while the plate 7 extends only to a point some distance from the wall 3. In practice however, the plate 7 may also extend to the wall 3.

The lower wall 1, the plates 7 to 15 and the upper Wall 2 form, with the longitudinal walls 5 and 6, compartments 21 to 30 within which the liquids flow. Each of compartments 21 to 30 communicates on each side with the compartments adjacent thereto, except that on the side of the wall 4 compartment 29 communicates only with the compartment which is situated below, i.e., with compartment 28. It does not communicate with the compartment which is situated above, i.e., compartment 30. If the plate 7 extends to against the transverse wall 3, compartment 22 on the side of said transverse wall 3 communicates, in that case, only with compartment 23 which is situated above. It does not communicate with compartment 21 which is situated below. At any rate, even if the plate 7 does not extend to the transverse wall 3, as is the case as shown in FIG. 1, no fluid stream is produced in the passage which remains open between the plate 7 and the transverse wall 3. This is due to the fact that the heavier liquid of compartment 21 does not rise through said passage and the lighter liquid introduced into the compartment 22 does not flow down through said passage. This is further described hereinafter.

The compartment 21 is intended to contain dilute alcohol for carrying soaps away without said alcohol being mixed with miscella. To this end, the transverse wall 3 has a discharge opening 31 at the level of the compartment 21. Similarly, compartment 30 is intended to withdraw washed miscella without the latter being mixed with the alcohol. To this end, the transverse wall 4 has a discharge opening 32 at the level of the upper compartment 30. It is to be noted that the dilute alcohol constitutes the heavier liquid and that the miscella constitutes the lighter liquid. The light liquid, i.e., miscella, is admitted into the vessel through an inlet opening 33 provided in the transverse wall 3 at the level of the lower portion of compartment 22. The heavy liquid, i.e., dilute alcohol, is admitted into the vessel through the inlet opening 34 provided in the transverse wall 14 at the level of the upper portion of compartment 29. The light liquid obviously tends to rise into the vessel, while the heavy liquid tends to flow down into the vessel. Thus an overall countercurrent effect is produced. However, in each of the intermediate compartments, i.e. in each compartment 22 to 29, means are provided which mix intimately the two liquids entering the compartment and which in addition propel said liquid mixture through the compartments. Said means are comprised of rotating stirrers designated by 35 in FIG. 1 and shown in detail in FIGS. 2 and 3.

Said rotating stirrers are arranged in the compartments 22 to 29 on the sides thereof. The side on which the stirrers are located comprise those with flanges 16 and 18, or 16 and 17, or 17 and 19 which are opposite. The side of the compartment where the rotating stirrer 35 is provided is always the entry side of the compartment. This is due to the fact that the stirrers, as further described hereinafter, propel the liquids mixed in the compartment to the other end of the compartment.

Each of the stirrers 35 com rises a shaft comprised of a hollow central part 36, a spindle 37 and a solid part 38 forming spindle at the other end. The shaft extends in transverse direction of the vessel and the hollow part 36 extends from the longitudinal wall to the longitudinal wall 6. Said hollow part 36 has four blades 39 arranged in planes passing through the geometrical axis 20 of the shaft, said blades forming angles of 90 between them. Said blades 39 extend from the hollow part 36 of the shaft to some distance from the plates delimiting the compartment involved. FIGS. 2 and 3 relating to compartment 24, the plates involved are plates 9 and 10. The hollow part of the shaft is in a chamber 40 formed by sheets 41 and 42 bound to the plates 9 and 10. On the side of the flange 17, the sheet 41 has a flange 43 parallel to said flange 17, and the sheet 42 comprises a flange 44 parallel to flange 16 on the side of the latter. The sum of the heights of the flanges 43 and 44 is less than the distance between sheets 41 and 42 and also the sum of the heights of the flanges 16 and 17 is less than the distance between plates 9 and 10. A passage thus remains free, on the one hand, between flanges 16 and 17 of the 4 plates 10 and 9 and, on the other hand, between flanges 43 and 44 of sheets 41 and 42.

On the compartment side, sheet 41 comprises a vertical flange 45 having a horizontally curved end 46. Sheet 42 comprises a vertical flange 47. A passage remains free between the curved end 46 of the flange 45 and the lower edge 48 of the flange 47. The flange 45 is offset towards the compartment with respect to flange 47 The direction of rotation of the shaft is indicated by arrow 49. The flanges 16 and 17 and the flanges 43 and 44 form a double wall of the chamber 40, said double wall having median slots 50 and 51. The flanges 45 and 47 form another wall delimiting the chamber 40 on the compartment side and having also a median slot 52. The flange 45 forms the lower part of the wall.

Each of the intermediate compartments 22 to 29 contains on the shaft side a horizontal partition 53 extending in transverse direction and connected to transverse wall 3 or 4 situated on the mixing device side. In longitudinal direction, the partition 53 extends into the compartment to a point close to the mixing device, i.e., to a location between the passage 51 of flanges 43 and 44 and the passage 50 of flanges 16 and 17. The passage 50 is thus divided into an upper portion and a lower portion.

Outside the vessel, a second wall 54 is provided near the longitudinal wall 5. Similarly, along the longitudinal wall 6, a second longitudinal wall 55 is provided outside the vessel. The assemblies of said walls 5 and 54, on the one hand, and 6 and 55, on the other hand, contain the shaft bearings.

The support 56 of the spindle 37 is entered into a tube 57 welded to walls 54 and 5. The spindle 37 is surrounded by the jacket 58 supported by the barrel 59 accommodated in the support 56. The barrel 59 is fixed to the support 56 by a screw 60 the head of which bears on the washer 67. The collar 61 of the support 56 is fixed to the wall 54 by screws 62 and nuts 63; the head of the screws 62 maintains a washer 64 against the collar 61 of the support 56. A ring 92 ensures the sealing be tween the wall 54 and the collar 61 of the support 56. The latter is provided with a central opening receiving the spindle 37 of the shaft. Said opening is normally closed by a plug 65 with threaded rod, said plug maintaining the washer 66 against the support 56.

The solid part 38 of the shaft is carried by the support 68 fixed to the wall 55 by means of screws 69 and nuts 70. The head of each screw 69 maintains a washer 71 against the collar 72 of the support 68. A joint 73 ensures the sealing between the wall 55 and the collar 72 of the support 68. The latter comprises a cylindrical end 74 mounted in the tube 75 which is welded to the wall 6 and to the wall 55. The outside end of the solid part of the shaft 38 is supported by the bearing 76 which is mounted in the collar 77 forming part of the support 68. A cover 78 retains the bearing and is fixed in turn to the collar 77 by means of screws 79 which maintain washers 80 against the flange 81 of the cover 78. Rings 82 and 83 provide the sealing between the part 38 of the shaft, on the one hand, the support 68 and the cover 78, on the other hand. The bearing 76 is thus mounted in a sealed area.

The sealing between the solid part 38 of the shaft and the cylindrical end 74 of the support 68 is ensured by glands 84 which are pressed against the flange 85 of the cylindrical end 74 of the support 68 by the stuffing-box 86 fixed to the wall 55 by means of screws 87 and nuts 88. The washers 89 are retained between the heads of the screws 87 and the stuffing-box 86. By a device not shown in the figures, the shaft is rotated in the direction of the arrow 49 of FIG. 3. Through the movement of the blades 39, an intimate mixture of the two liquids entering the chamber 40 is thus formed and the liquids are propelled out of the chamber 40 through the passage 52 due to the offset between the flange 45 and the flange 5. 47 and due to the presence of a curved part 46 of the flange 45.

The dilute alcohol admitted through opening 34 in the compartment 29 enters the chamber 40 of said compartment through the passages 50 and 51. Simultaneously, the light liquid, i.e. miscella, coming from compartment 28 rises to compartment 29 and is directed by partition 53 through the lower part of the pasasge 50 and through the passage 51 into the same chamber 40 of compartment 29. In this chamber 40, the dilute alcohol and the light liquid coming from compartment are intimately mixed due to the movement of the blades 39 and are propelled as a mixture through compartment 29 in the direction of the arrows 90. The miscella entering the compartment 29 is already partially washed when passing through compartments 22 to 28 from the inlet opening 33.

Under gravity, a decantation proceeds in compartment 29 and, at the outlet from the latter, the washed miscella, forming the lighter phase, will ocupy the upper part of compartment 29, while the alcohol already partially loaded with soap, which forms the heavier phase, will occupy the lower part of the same compartment 29. The washed miscella coming out of compartment 29 will flow through compartment 30 towards the outlet 32 of the apparatus. On the other hand, the alcohol containing soap coming from compartment 29 will come down and will be directed by partition 53 of compartment 28 through passages 50-51 into the chamber 40 of compartment 28. The alcohol entering the chamber 40 of compartment 28 is mixed therein by means of blades 39 of the stirrer of said compartment with the partially washed miscella rising from compartment 27 and directed by partition 53 through the lower part of passage 50 and the passage 51 into the same chamber 40. At the inlet to compartment 28, an intimate mixture is produced, said mixture comprising the miscella already partially washed in compartment 27 and the alcohol already partially loaded with soap coming from compartment 29. The mixture thus produced at the inlet to compartment 23 will be propelled in the direction of arrows 91 towards the outlet of compartment 28 where the partially washed miscella will be supplied, as described above, to the inlet of compartment 29, while the alcohol containing soap will be supplied to the inlet of compartment 27.

Thus, from one compartment to another, the alcohol will progressivley become more concentrated with soap, while the miscella is more and more freed from soap. The alcohol layer coming out from compartment 23 and supplied to the inlet of compartment 22 is mixed therein with not yet treated miscella supplied through opening 33. The miscella which is treated in compartment 22 is discharged towards compartment 23 at the outlet from compartment 22 where the alcohol loaded with soap comes down towards compartment 21 through which said alcohol loaded with soap is directed towards the discharge opening 31.

In the whole operation, miscella is thus treated in counter-current fashion by dilute alcohol, while in each compartment the paths of the two liquids to be separated are in parallel relationship and along the same direction, which prevents any turbulence and any parasitic recycling in closed circuit.

The various compartments may have a very low height, for instance 50 to 100 mm., which permits within a very limited space a multi-stage column. The room taken by the apparatus is thus much reduced and the erection of the apparatus is very inexpensive. The inactive volume of the liquids is also much reduced due to the small room taken by the apparatus, and the operating rate is very high.

What I claim is:

l. An apparatus for contacting two liquids of different specific weights so as to carry out a procedure of solvent extraction comprising a substantially rectangular vessel having four substantially vertical walls, two of said walls extending in a first direction and the remaining two walls extending in a second direction which is perpendicular to the first direction, said vessel having a plurality of substantially parallel and horizontal plates delimiting a series of compartments within said vessel, the said plates extending to the walls of said vessel which extend in said first direction and extending to a point spaced from the walls which extend in the second direction thus defining a passage permitting the flow of liquids between the edge of each of the parallel plates and the walls extending in the second direction, the lower compartment of said vessell having a discharge opening, the upper compartment of said vesel having a discharge opening, the compartment of said vessel immediately above the lower compartment having an inlet opening situated on the same side as the discharge opening of said lower compartment, the compartment of said vessel immediately below the upper compartment having an inlet opening situated on the same side as the discharge opening of said upper compartment, each of the intermediate compartments having a chamber delimited by two vertical walls which walls extend the whole height of the compartment, are parallel to said second direction, and each of the vertical walls delimiting said chambers having a median slot extending in said second direction over the entire width of the vessel, said chambers being alternately arranged on one end and on the other end of the compartments, the chamber of the compartment which is directly above the lower compartment being situated on the end of the inlet opening of said compartment and the chamber of the compartment which is directly below the upper compartment being situated on the end of the inlet opening of said compartment, the portion of the chamber wall which is located on the compartment side of the chamber and which is below the median slot being offset towards the compartment with respect to the upper part of the same wall and in addition having a flange which is bent toward the inside of the chamber, each of said chambers being provided with a rotatable shaft, said shafts extending in said second direction and having blades attached thereto said blades lying in planes which extend through and include the geometrical axis of the shaft, a horizontal partition lying in said second direction and extending into each of said chambers from the wall of the vessel which extends in the second direction through the median slot in said chamber wall adjacent said last mentioned vessel wall.

2. An apparatus as claimed in claim 1, wherein the said chamber contains an additional vertical wall between the wall of the chamber containing the median slot through which the horizontal partition extends and the shaft, said wall extending the whole height of the chamber and having a median slot extending in said second direction over the entire width of the vessel, the said horizontal partition extending only through the median slot of the chamber wall which is in the closest proximity to the vessel wall from which the horizontal partition extends.

References Cited by the Examiner UNITED STATES PATENTS 2,201,550 5/1940 Van Dijck 23270 X 2,775,543 12/1956 Carver 23270.5 X 2,777,758 1/1957 Pokorny 23270.5 3,032,403 5/1962 Kohl 23-2705 FOREIGN PATENTS 772,060 4/ 1957 Great Britain.

NORMAN YUDKOFF, Primary Examiner.

S. EMORY, Assistant Examiner.

Claims (1)

1. AN APPARATUS FRO CONTACTING TWO LIQUIDS OF DIFFERENT SPECIFIC WEIGHTS SO AS TO CARRY OUT A PROCEDURE OF SOLVENT EXTRACTION COMPRISING A SUBSTANTIALLY RECTANGULAR VESSEL HAVING FOUR SUBSTANTIALLY VERTICAL WALLS, TWO OF SAID WALLS EXTENDING IN A FIRST DIRECTION AND THE REMAINING TWO WALLS EXTENDING IN A SECOND DIRECTION WHICH IS PERPENDICULAR TO THE FIRST DIRECTION, SAID VESSEL HAVING A PLURALITY OF SUBSTANTIALLY PARALLEL AND HORIZONTAL PLATES DELIMITING A SERIES OF COMPARTMENTS WITHIN SAID VESSEL, THE SAID PLATES EXTENDING TO THE WALLS OF SAID VESSEL WHICH EXTEND IN SAID FIRST DIRECTION AND EXTENDING TO A POINT SPACED FROM THE WALLS WHICH EXTEND IN THE SECOND DIRECTION THUS DEFINING A PASSAGE PERMITTING THE FLOW OF LIQUIDS BETWEEN THE EDGE OF EACH OF THE PARALLEL PLATES AND THE WALLS EXTENDING IN THE SECOND DIRECTION, THE LOWER COMPARTMENT OF SAID VESSELL HAVING A DISCHARGE OPENING, THE UPPER COMPARTMENT OF SAID VESSEL HAVING A DISCHARGE OPENING, THE COMPARTMENT OF SAID VESSEL IMMEDIATELY ABOVE THE LOWER COMPARTMENT HAVING AN INLET OPENING SITUATED ON THE SAME SIDE AS THE DISCHARGE OPENING OF SAID LOWER COMPARTMENT, THE COMPARTMENT OF SAID VESSEL IMMEDIATELY BELOW THE UPPER COMPARTMENT HAVING AN INLET OPENING SITUATED ON THE SAME SIDE AS THE DISCHARGE OPENING OF SAID UPPER CONPARTMENT, EACH OF THE INTERMEDIATE COMPARTMENTS HAVING A CHAMBER DELIMITED BY TWO VERTICAL WALLS WHICH WALLS EXTEND THE WHOLE HEIGHT OF THE COMPARTMENT, ARE PARALLEL TO SAID SECOND DIRECTION, SAND EACH OF THE VERTICAL WALLS DELIMITING SAID CHAMBERS HAVING A MEDIAN SLOT EXTENDING IN SAID SECOND DIRECTION OVER THE ENTRIE WIDTH OF THE VESSEL, SAID CHAMBERS BEING ALTERNATELY ARRANGED ON ONE END AND ON THE OTHER END OF THE COMPARTMENTS, THE CHAMBER OF THE COMPARTMENTS WHICH IS DIRECTLY ABOVE THE LOWER COMPARTMENT BEING SITUATED ON THE END OF THE INLET OPENING OF SAID COMPARTMENT AND THE CHAMBER OF THE COMPARTMENT WHICH IS DIRECTLY BELOW THE UPPER COMPARTMENT BEING SITUATED ON THE END OF THE INLET OPENING OF SAID COMPARTMENT, THE PORTION OF THE CHAMBER WALL WHICH IS LOCATED ON THE COMPARTMENT SIDE OF THE CHAMBER AND WHICH IS BELOW THE MEDIAN SLOT BEING OFFSET TOWARDS THE COMPARTMENT WITH RESPECT TO THE UPPER PART OF THE SAME WALL AND IN ADDITION HAVING A FLANGE WHICH IS BENT TOWARD THE INSIDE OF THE CHAMBER, EACH OF SAID CHAMBERS BEING PROVIDED WITH A ROTATABLE SHAFT, SAID SHAFTS EXTENDING IN SAID SECOND DIRECTION AND HAVING BLADES ATTACHED THERETO SAID BLADES LYING IN PLANES WHICH EXTEND THROUGH AND INCLUDE THE GEOMETRICAL AXIS OF THE SHAFT, A HORIZONTAL PARTITION LYING IN SAID SECOND DIRECTION AND EXTENDING INTO EACH OF SAID CHAMBERS FROM THE WALL OF THE VESSEL WHICH EXTENDS IN THE SECOND DIRECTION THROUGH THE MEDIAN SLOT IN SAID CHAMBER WALL ADJACENT SAID LAST MENTIONED VESSEL WALL.

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