JP2679630B2 - Bar plate type liquid-liquid contact tower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-liquid contact tower, and more particularly to an improvement of a liquid-liquid contact tower in which two mutually insoluble liquids are brought into continuous countercurrent contact by utilizing the difference in specific gravity between them. .
Its typical application is an apparatus for liquid-liquid extraction or liquid-liquid reaction, which is one of the important unit operations in petroleum refining, petrochemicals, coal chemistry, nuclear industry, and various other process industries.

[0002]

BACKGROUND ART Countercurrent type liquid-liquid contact towers used for liquid-liquid extraction and the like include non-stirring type towers such as a perforated plate tower, a packed tower, a baffle tower, a rotating disk tower, and an Oldshoe-Rushton ( Ol
dshueRushton) tower, pulsating extraction tower, reciprocating extraction tower, etc.

The latter stirring-type contact tower has a large contact efficiency per unit height, but has a mechanical driving part,
It has the drawbacks of high equipment costs and troublesome maintenance. Although the former non-stirring type contact tower has a relatively low contact efficiency, it is advantageous that the facility cost is low and the maintenance is easy.

The inventors of the present invention have made an improvement study on the former non-stirring type liquid-liquid contact tower, which has the advantages of low facility cost and easy maintenance, especially a perforated plate tower having a relatively high contact efficiency. Has continued.

As shown in FIGS. 15 and 16, the conventional perforated plate column (in the illustrated example, the light liquid (L) is the dispersed phase and the heavy liquid (H) is the continuous phase), the column (20) A heavy liquid inlet (21) and a light liquid outlet (22) are provided in the upper part, a light liquid inlet (23) and a heavy liquid outlet (24) are provided in the lower part, and a plurality of trays (25) are arranged in the tower. It is the structure that was set up.

As shown in detail in FIG. 16, the shelf (25) has a circular perforated plate which is cut out to form a flow path.
It consists of a perforated plate (26) placed horizontally, and a vertical plate (27) extending vertically downward (dispersed phase supply side) from the end on the flow path side. The part formed by the flow path and the vertical plate of the perforated plate is an overflow pipe (the example shown is called "downcomer"), and the continuous phase liquid flow through which only the continuous phase (heavy liquid) passes. The channels (29) are formed, and the pores of the perforated plate 26 become the dispersed phase liquid flow paths (28) through which only the dispersed phase (light liquid) passes.

The operation of this perforated plate tower is carried out by supplying the light liquid from the light liquid inlet (23) at the bottom of the tower (20) and the heavy liquid from the heavy liquid inlet (21) at the upper part.

At this time, both liquids are supplied so that one is a disperse phase and the other is a continuous phase. In the case where the light liquid shown in the figure is a disperse phase, with respect to the supply amount of the heavy liquid which is a continuous phase, While the dispersed phase droplets stay below the perforated plate (26) and move upward, the droplets accumulate and coalesce to form a dispersed phase layer, and the dispersed phase layer forms a dispersed phase liquid flow in the holes. The light liquid is supplied at a flow rate condition so as to flow vertically upward from the passage (29).

As described above, the light liquid and the heavy liquid are mixed with each other in the tower (2
By making liquid-liquid contact in 0) continuously in countercurrent, the components in the heavy liquid can be extracted with the light liquid, and vice versa, the components in the light liquid can be extracted with the heavy liquid. After causing a chemical reaction between the liquid and the heavy liquid, the light liquid that has finished its action is extracted from the light liquid outlet (22) and the heavy liquid is continuously extracted from the heavy liquid outlet (24).

[0010]

In the perforated plate column as described above, although the liquid-liquid contact efficiency per unit plate is higher than that of the baffle column having a larger opening area than the perforated plate, the above-mentioned flow conditions of the dispersed phase are required. In order to operate in a range satisfying the above condition, the opening area of the dispersed phase liquid flow path (29) which is a hole provided in the perforated plate (26) must be reduced, and the supply amount of the dispersed phase liquid is increased. I can't. Therefore, there is a drawback that the amount of processing liquid is small.

The inventors have made the following attempts to solve these drawbacks.

First, using a conventional perforated plate tower, the liquid amount was gradually increased to a flooding region while the ratio of the dispersed phase flow rate to the continuous phase flow rate was kept constant, and the liquid-liquid contact efficiency was observed.
The efficiency was lower than that in normal operation, and it was impossible to maintain a high contact efficiency and increase the amount of treatment liquid.

Next, the dispersed phase liquid flow path (2) of the perforated plate (26)
9) It was tried to increase the opening area ratio by increasing the pore diameter or increasing the number of pores to increase the amount of dispersed phase liquid, but the thickness of the dispersed phase layer under the perforated plate (26) was Since it became thin, and even a slight change in the operating conditions completely eliminated the dispersed phase, stable operation was difficult and stable liquid-liquid contact efficiency could not be obtained.
Further, it was found that the efficiency was significantly reduced when the dispersion phase was completely eliminated, and it was not possible to conclude that this method was effective.

An object of the present invention is to provide a liquid-liquid contact tower capable of simultaneously achieving a high throughput and a high contact efficiency, which could not be expected in the conventional non-stirring type liquid-liquid contact tower.
That is, even if the flow area of the dispersed phase is increased and the amount of the processing liquid is significantly increased, the droplets of the dispersed phase are surely coalesced to form a dispersed phase coalescent layer, and the coalesced layer is a droplet. The object of the present invention is to provide a liquid-liquid contact tower capable of maintaining high contact efficiency by ensuring the repetition of the steps of uniformly dispersing the liquid.

[0015]

In the dam plate type liquid-liquid contact tower of the present invention, a heavy liquid is supplied from the upper part of the tower and a light liquid is supplied from the lower part, one of which is a dispersed phase and the other is a continuous phase. In such a liquid-liquid contacting column having a plurality of trays, in which both liquids are continuously countercurrently contacted in the column, the flow path of the continuous phase liquid and the dispersed phase liquid occupies a part of the cross section of the column in the horizontal direction. And the shelf plate that left, extending vertically from the flow path side end of the shelf plate in the supply direction of the dispersed phase,
It has a shelf consisting of a weir plate that has an opening that forms a flow path for the dispersed phase liquid near the shelf, and allows the dispersed phase droplets from the previous shelf to stay in the next shelf and It is characterized in that the liquid droplets are coalesced between the two to form a dispersed interlocking layer, and the coalescing layer flows out horizontally from the opening of the dam plate.

The present invention will be described in more detail below with reference to the drawings. In the figure, the same parts as those of the conventional perforated plate are designated by the same reference numerals.

The first embodiment of the barrier plate type liquid-liquid contact tower of the present invention is, as shown in FIG. 1, provided with a heavy liquid inlet (21) and a light liquid outlet (22) at the upper part of the tower (10). The tower (1
0) A light liquid inlet (23) and a heavy liquid outlet (24) are provided in the lower part, and a plurality of trays (1) are arranged in the tower (10).

As shown in FIGS. 2 and 3, the tray (1) used in the apparatus of the present invention has a disc (not shown) partially cut away to form a flow path (4) for a continuous phase liquid and a dispersed phase liquid. Which is formed horizontally and which is placed horizontally, and a weir plate (3) extending vertically (dispersed phase supply side) vertically from the end of the liquid flow path (4) of the shelf plate (2).
The barrier plate (3) is provided with an opening (5) on the side of the barrier plate (3) close to the shelf plate, which serves as a flow path for the dispersed phase liquid.

Below the shelf plate (2) (dispersed phase supply side),
As shown in FIG. 4, while the droplets of the dispersed phase are accumulated, they are accumulated and united to form a dispersed phase combined layer. The formed dispersed phase layer flows out horizontally from the opening (5) of the dam plate (3).

The operation of the liquid-liquid contact tower of the present invention is carried out from the light liquid inlet (23) at the bottom of the tower (10) so that one is a dispersed phase and the other is a continuous phase, as in the conventional perforated plate tower. Supply the liquid and supply the heavy liquid from the upper heavy liquid inlet (21),
On the other hand, the light liquid which has already been in liquid-liquid contact is extracted from the light liquid outlet (22) in the upper part of the tower (10), and the heavy liquid is continuously extracted from the heavy liquid outlet (24) in the lower part of the tower (10). By.

In the liquid-liquid contact tower in which a plurality of trays (1) having the above structure are alternately arranged in the tower (10) at relative positions rotated by 180 °, the liquid flow path (4) is The passing continuous phase liquid and dispersed phase liquid move in a meandering manner from one side of the column wall to the other side, thereby increasing the chances of liquid-liquid contact.

The dam plate (3) is required to have a height such that the dispersed phase droplets do not overflow, but it can be made lower than the height of the downcomer used in the conventional perforated plate column.
That is, in the conventional perforated plate tower, since the droplets form a laminated layer during the movement in the vertical direction (see FIG. 16), the height of the vertical plate (27) is increased by a distance required for forming the laminated layer. Although required, in the liquid-liquid contact tower of the present invention, as shown by the arrow in FIG. 4, the dispersed phase droplets accumulate and coalesce while moving horizontally under the shelf plate (2), so that high The distance in the vertical direction can be shortened.

The opening area ratio of the opening (5), which is the flow path of the dispersed phase liquid provided on the dam plate, is appropriately in the range of 2 to 30%, preferably 3 to 15% with respect to the column cross-sectional area. is there. The shape of the opening (5) provided on the barrier plate can be any shape as long as it meets the purpose of the present invention. In addition to the shape shown in FIG. 3, various embodiments such as those shown in FIGS. It is possible. The opening area can be adjusted according to the amount of liquid processed, and the degree of freedom in design is large.

8 to 10 show a second embodiment of the present invention. This embodiment is a two-pass type (two liquid flow paths) liquid-liquid contact tower in which two shelves form one set and a higher throughput is possible. (The same parts as those in the above-mentioned embodiment are designated by the same reference numerals.) That is, as shown in FIG. 9, the first tray (1a) has a continuous phase liquid and a dispersed phase liquid in the substantially central portion thereof. Shelf board (2a) having a first flow path (4a) passing through
And a weir plate (3a) extending vertically downward from the end of the first flow path (4a) of the shelf plate (2a), and has the same function as the shelf (1) shown in the above embodiment.

The second tray (1b) is the first tray (1a).
The shelf plate (2b) shown in FIG. 10 spreads so as to cover the first flow path (4a) of the second flow path (4b,
4b) is provided, and each second flow path (4b, 4)
It consists of a weir plate (3b, 3b) extending vertically from the end of b) and serves the same function as the shelf (1) described with respect to the previous embodiment.

11 to 14 show a third aspect of the present invention. This embodiment is a 4-pass type liquid-liquid contact tower in which the number of common liquid flow paths for the continuous phase liquid and the dispersed phase liquid is increased to four.

Also in this mode, as in the second mode, the rack is a two-stage set.

The first shelf (1c) has three first flow paths (4
Shelf board (2c) divided into four having c) and shelf board (2c)
And a weir plate (3c) extending vertically downward from the end of each of the first flow channels (4c), and the weir plate (3c) is provided with an opening (5c) which serves as a flow channel for only the dispersed phase liquid. .

In the second shelf (1d), the shelf plate (2d) divided into three spreads so as to cover the above-mentioned three first channels (4c) from below, and the four second channels (2d). (4d) is formed, and there is a weir plate (3d) extending vertically downward from the end of each second flow path (4d) of the shelf plate (2d), and the weir plate (3d) has a dispersed phase. An opening (5d) is provided which serves as a flow path for only the liquid.

The first tray (1c) and the second tray (1d) are both the tray (1) of the first aspect described above.
In principle, the function of the second embodiment is the same as that of the second embodiment, but as will be understood from the description of the second embodiment, the tray (1
It has the same merit as the group of a) and (1b).

In the liquid-liquid contact towers of the second and third embodiments (these and the various modes in which the number of liquid flow paths considered on the extension thereof are increased are collectively referred to as "multipass type"), First channel (4a, 4c) and second channel (4b, 4)
By arranging d) in the vertical direction so as not to overlap with each other, it is easy to design so as to obtain a flow passage area corresponding to the increase in the processing liquid amount. In particular, when the demand for scale-up is met, a multi-pass type can be used to obtain a liquid-liquid contact tower with a large tower diameter.

[0032]

The plates (1, 1a, 1b, of the liquid-liquid contact tower of the present invention,
1c, 1d), the dispersed-phase liquid layer (5, 5a, 5b, 5c, 5d) opened according to the desired treatment amount, the dispersed-phase _single layer (L ₃ ) becomes a jet (L ₁ ) in the horizontal direction. Flowing out, it becomes droplets (L ₂ ) by the shear stress received from the continuous phase liquid (H), and the droplets move upward while coming into contact with the continuous phase liquid and move horizontally below the next tray. It is possible to extract the components in the heavy liquid with the light liquid by accumulating and reliably coalescing to form a dispersed phase coalescent layer while repeating the dispersion and coalescence of the droplets. On the contrary, the components in the light liquid can be extracted with the heavy liquid, and the action of causing a chemical reaction between the light liquid and the heavy liquid can be performed with high contact efficiency.

In the first mode, the movement of the droplets below the tray is performed mainly in the direction parallel to the paper surface of FIG. 4, and the movement of the droplets in the second aspect is also close to this. In the third mode, the operation is performed by moving the underside of the channel-shaped shelf plate perpendicularly to the paper surface of FIG.
By arranging the openings (5c and 5d) of the barrier plate at positions separated from each other as seen in FIG. 12, a sufficient movement distance can be secured together with the increase in the tower diameter, and the accumulation of droplets and coalescence can be achieved. Definitely done.

[0034]

EXAMPLES In each of the following comparative examples and examples, methacrylic acid was extracted with isooctane (hereinafter, referred to as a solvent) from a methacrylic acid aqueous solution (hereinafter, referred to as a raw material) having a concentration of 12% (weight%, the same hereinafter). Liquid-liquid extraction operation was performed.

[Comparative Example 1] An extraction apparatus having a structure shown in FIG. 15 and FIG.
A perforated plate column having 10 mm holes and 5 holes (ratio of the cross-sectional area of the downcomer channel to the tower cross-sectional area of 14%) was arranged at a tray interval of 150 mm.

The raw material was a heavy liquid and the solvent was a light liquid. The latter was used as a dispersed phase and the solvent ratio (solvent / raw material) was selected to be 1.38 / 1, and liquid-liquid contact was carried out at a temperature of 20 ° C. and atmospheric pressure.

When the raw material supply amount is 56 kg / Hr and the solvent (methacrylic acid concentration is 0%) supply amount is 78 kg / Hr, the raffinate liquid has a methacrylic acid concentration of 7.3% at a liquid flow rate of 53 kg / Hr. The height per theoretical step (hereinafter “HETS”)
That. The lower the efficiency, the better. ),
It was 2.9 m.

The raw material and the solvent are supplied in an increased amount,
Flooding occurred when the amount was 4 kg / hr and the solvent was 116 kg / hr.

[Embodiment 1] An extraction device is a weir plate type liquid-liquid contactor of the present invention having a structure shown in FIGS. 1 to 4, wherein a liquid passage opening area of a shelf plate is provided in a tower having an inner diameter of 75 mm. The ratio (liquid flow passage area / column cross-sectional area) is 32%, and a tray having two square openings of 10 mm × 10 mm as a dispersed phase liquid flow passage is provided.
A 19-stage arrangement with a shelf interval of 75 mm was used. The conditions such as the solvent ratio other than the liquid supply amount were the same as in Comparative Example 1.

When the raw material supply rate is 84 kg / Hr and the solvent (methacrylic acid concentration 0%) supply rate is 116 kg / Hr, the raffinate liquid has a methacrylic acid concentration of 7.0% at a liquid flow rate of 80 kg / Hr. The HETS according to was 2.7 m.

The raw material 1 is increased by increasing the supply amounts of the raw material and the solvent.
When 13 kg / Hr and 156 kg / Hr solvent are used, the raffinate has a liquid flow rate of 107 kg / Hr and a methacrylic acid concentration of 7.4%.
HETS was 3.0 m.

Table 1 below summarizes the throughput and extraction efficiency of Comparative Example 1 and the present invention.

Table 1 Liquid supply amount (kg / Hr) Extraction efficiency Comparative Example 1 Example 1 Raw material Solvent extraction rate HETS Extraction rate HETS (%) (m) (%) (m) 56 78 78 42 2.9- -84 116 ** 45 45 2.7 113 156 --42 3.0 * Occurrence of flooding From the results of Table 1, in the case of using the tower of the present invention, compared with the case of using the conventional perforated plate tower, liquid It can be seen that the liquid-liquid contact efficiency as a whole does not decrease even if the supply amount is increased and the treatment amount is greatly increased.

[Comparative Example 2] As an extraction apparatus, which is a conventional apparatus shown in FIGS. 15 and 16, a column having a hole diameter of 4 mm and a number of 72 holes (a downcomer section flow path in a column having an inner diameter of 300 mm) is used. The ratio to the cross-sectional area of the tower is 14%)
A perforated plate tower having 10 stages arranged in mm was used.

The raw material was a heavy liquid and the solvent was a light liquid. The latter was used as a dispersed phase and the solvent ratio (solvent / raw material) was selected to be 1.38 / 1, and liquid-liquid contact was carried out at a temperature of 20 ° C. and atmospheric pressure.

When the raw material supply rate is 900 kg / Hr and the solvent (methacrylic acid concentration 0%) supply rate is 1240 kg / Hr, the raffinate liquid has a methacrylic acid concentration of 7.4% at a liquid flow rate of 855 kg / Hr. Then, HETS was determined to be 4.0 m.

The raw material 1 is increased by increasing the supply amount of the raw material and the solvent.
Flooding occurred when the solvent was 350 kg / hr and the solvent was 1860 kg / hr.

[Embodiment 2] As the extraction apparatus, the weir plate type liquid-liquid contactor of the present invention having the structure shown in FIGS. 1 to 4 was used. The liquid flow passage area / column cross-sectional area) is 32%, and the dispersed phase liquid flow passage has a vertical length of 4
A rack having four rectangular openings of 0 mm × width 20 mm and having 19 racks arranged at a rack interval of 100 mm was used. The conditions such as the solvent ratio other than the liquid supply amount are the same as in Comparative Example 2.

When the raw material supply rate is 1350 kg / Hr and the solvent (methacrylic acid concentration 0%) supply rate is 1860 kg / Hr, the raffinate liquid has a methacrylic acid concentration of 4.7 at a liquid flow rate of 1250 kg / Hr.
%, And HETS by liquid-liquid equilibrium calculation was 2.5 m.

The raw material 1 and the solvent supply amount are increased to increase the raw material 1.
When 800 kg / Hr and 2490 kg / Hr solvent are used, the raffinate liquid has a liquid flow rate of 1670 kg / Hr and a methacrylic acid concentration of 5.2%.
And HETS was 2.7 m.

The throughput and extraction efficiency of Comparative Example 2 and Example 2 are compared and summarized in Table 2 below.

Table 2 Liquid supply amount (kg / Hr) Extraction efficiency Comparative Example 2 Example 2 Raw material Solvent extraction rate HETS Extraction rate HETS (%) (m) (%) (m) 900 1240 42 4.0- -1350 1860 * * 64 2.5 1800 2490--60 2.7 * Occurrence of flooding From the results in Table 2, when the tower diameter was increased, Table 1
It can be seen that a higher effect was obtained than the result of. In detail, when the tower diameter is large, the contact efficiency per plate is improved, which means that the distance that droplets move horizontally under the shelf plate becomes longer, and the formation of multiple layers is more reliable. Therefore, it is considered that the efficiency is improved.

[0053]

In the liquid-liquid contact tower of the present invention, the area of the opening serving as the flow path of the dispersed phase liquid is made larger than the opening area of the holes provided in the conventional perforated plate tower, and the droplets of the dispersed phase are Since the diameter can be increased, the throughput can be greatly increased.
In addition, since the dispersed phase is surely repeatedly dispersed and united in a short distance in the vertical direction, the liquid-liquid contact efficiency equal to or higher than that of the conventional porous plate column is secured.

Further, in the present invention, since the droplets of the dispersed phase flow out in a substantially horizontal direction and come into contact with the flowing continuous phase so as to collide with each other, the dispersed phase liquid column is small due to the strong shearing force of the continuous phase fluid. The liquid-liquid contact efficiency is improved as compared with the conventional case, because the droplets are torn off and uniformly dispersed.

Furthermore, since the dispersed and combined layers are caused to flow out in the horizontal direction and the accumulation and coalescence of the droplets are carried out during the horizontal movement, it is possible to keep the height of the tower low, and if the towers have the same height. Since a large number of shelves can be arranged, the total liquid-liquid contact efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing the overall structure of a first embodiment of a barrier plate type liquid-liquid contactor of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

3 is a vertical cross-sectional view taken along line BB of FIG.

FIG. 4 is a partially enlarged vertical sectional view in a use state for explaining the operation of the device of the present invention.

FIG. 5 is a vertical cross-sectional view similar to FIG. 3, showing another example of the barrier plate and the opening used in the first aspect of the device of the present invention.

FIG. 6 is a view similar to FIG.

FIG. 7 is a view similar to FIG.

FIG. 8 is an enlarged vertical sectional view similar to FIG. 4 for explaining the operation of the second aspect of the device of the present invention.

9 is a cross-sectional view taken along line CC of FIG.

10 is a transverse cross-sectional view taken along the line DD of FIG.

FIG. 11 is a vertical cross-sectional view (in the absence of liquid) similar to FIG. 4 showing an example of a weir plate and an opening of a shelf used in the third aspect of the device of the present invention.

12 is a vertical cross-sectional view of the device of FIG. 11 viewed from different angles on the axis by 90 °.

13 is a lateral cross-sectional view taken along the line EE of FIG.

14 is a lateral cross-sectional view taken along the line FF of FIG.

FIG. 15 is a view for explaining the structure of a conventional perforated plate type liquid-liquid contact tower and its operation.

16 is an enlarged vertical cross-sectional view of a portion of FIG. 15, corresponding to FIGS. 4 and 8. FIG.

[Explanation of symbols]

1,1a, 1b, 1c, 1d Shelf 2,2a, 2b, 2c, 2d Shelf 3,3a, 3b, 3c, 3d Weir plate 4,4a, 4b, 4c, 4d Liquid channel 5,5a, 5b , 5c, 5d openings 10 liquid-liquid contact tower (present invention) 20 liquid-liquid contact tower (prior art) 21 heavy liquid inlet 22 light liquid outlet 23 light liquid inlet 24 heavy liquid outlet L light liquid (dispersed phase) L ₁ jet L ₂ Droplet L ₃ Dispersed phase Single layer H Heavy liquid (continuous phase)

Claims (4)

(57) [Claims] 1. A heavy liquid is supplied from the upper part of the column and a light liquid is supplied from the lower part, and both liquids are continuously countercurrently contacted in the column so that one is a dispersed phase and the other is a continuous phase. In a liquid-liquid contact tower having a plurality of trays, a shelf plate that occupies a part of the cross section of the tower in the horizontal direction and leaves a flow path of a continuous phase liquid and a dispersed phase liquid, and from the end of the shelf plate on the flow path side It has a shelf that extends vertically to the dispersed phase supply direction and that has a weir plate that has an opening that serves as a flow path for the dispersed phase liquid near the shelf plate. And the droplets coalesce during the retention to form a disperse interphase layer, and the monolayer flows out horizontally from the opening of the dam plate. Weir plate type liquid-liquid contact tower. 2. A plurality of trays having the same shape are arranged in a column at relative positions alternately rotated in the vertical direction by 180 degrees, and a continuous phase liquid and a dispersed phase liquid passing through a liquid flow path are provided. The dam plate type liquid-liquid contact tower according to claim 1, which is configured to meander from one side of the wall of the tower to the other side. 3. A tray consists of a first tray having a shelf plate on both sides of which a liquid flow path is formed, and a second tray having a liquid flow path on one side, which is a tower. The liquid flow paths are alternately arranged inside each other in such a positional relationship that they do not overlap in the vertical direction,
The dam plate type liquid-liquid contact tower according to claim 1, wherein the continuous-phase liquid and the dispersed-phase liquid are configured to repeat splitting and merging. 4. A first shelf having a shelf plate in which at least one liquid flow path is formed, and at least two liquid flow paths are perpendicular to the liquid flow paths of the first shelf. Consisting of a second shelf having a shelf plate formed in a positional relationship that does not overlap in the direction,
The dam plate-type liquid-liquid contact tower according to claim 1, wherein they are alternately arranged in the tower so that the continuous-phase liquid and the dispersed-phase liquid repeatedly divide and join.