A high efficiency liquid membrane type extraction column

Abstract

The application relates to a high-efficiency liquid membrane type extraction tower which comprises a tower body, a tower bottom, a tower top and a tower inner filler part. Through specific setting of a linear filler part of a linear physical structure in the tower and specific setting of distribution of the linear filler part, high mass transfer specific surface area and high mass transfer efficiency are realized during extraction of a liquid-liquid system extraction tower.

Description

Technical Field

[0001] This invention belongs to the field of extraction technology in chemical separation, and specifically relates to a novel liquid membrane extraction tower. Background Technology

[0002] Liquid membrane extraction combines the characteristics of extraction and membrane separation, integrating extraction and back-extraction. However, existing packed extraction towers suffer from low space utilization of bulk packing due to their tortuous paths, and both structured and bulk packing exhibit large flooding zones. While spray towers have smaller flooding zones, their efficiency is low. Therefore, there is an urgent need to propose a technical solution that combines the advantages of small flooding zones in spray towers with the high extraction efficiency of packed extraction towers for the back-extraction process of phenol loaded in organic phases.

[0003] Chinese utility model patent publication CN210434031U discloses a forced flow quasi-liquid membrane extraction separation enrichment device, which can be applied to the enrichment and separation process of high or low concentration, inorganic or organic solute components, and single or multiple solutes. However, its packing material is also a bulk packing material, which does not effectively combine the advantages of both. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a liquid film extraction tower that combines the advantages of a small flooding zone in a spray tower and the high extraction efficiency in a packed extraction tower. By enabling the dispersed phase to be distributed and transferred in a liquid film flow manner, and by selecting appropriate packing materials, the dispersed phase can flow on the online surface, thereby improving the mass transfer efficiency.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A high-efficiency liquid film extraction column includes a column body, a column bottom, a column top, and an internal packing component.

[0007] The tower base is located below the tower body, and the tower top is located above the tower body. The tower base, tower body, and tower top are interconnected, and the diameters of the tower base and tower top are larger than the diameter of the tower body.

[0008] A light phase outlet and a heavy phase inlet are provided on the side wall at the top of the tower, and a light phase inlet and a heavy phase outlet are provided on the side wall at the bottom of the tower.

[0009] The tower packing components include a line distributor, a perforated distributor, and line packing. The line distributor is located at the junction of the tower bottom and the tower body. The line distributor includes a horizontal disc and line connecting posts. The outer edge of the horizontal disc connects to the inner edge of the tower bottom. Multiple line connecting posts are vertically positioned on the top of the horizontal disc. Gaps are provided on the horizontal disc to allow material to flow vertically. The perforated distributor includes a supporting horizontal disc and a through-hole section. The outer edge of the supporting horizontal disc connects to the inner edge of the upper part of the tower body. The through-hole section is located on the inner circle of the supporting horizontal disc and has multiple through holes. Gaps are provided between the supporting horizontal disc and the through-hole section, allowing the line packing to pass through. Gaps in the perforated distributor allow material to flow vertically. Multiple line packings are provided, with the top of all line packings connecting to the top of the tower. The bottom of each line packing connects to multiple line connecting posts of the line distributor. The line packings pass through the through holes in the perforated distributor. The line packings are vertically positioned within the tower body and are always in a straight line.

[0010] The linear packing has a linear density of 1.5% to 3.5% within the tower body. Each piece of the linear packing is a single composite wire or a twisted composite wire made of two composite wires wound together. When the liquid flow rate in the tower body is less than the flow rate threshold, the linear packing is set to the single composite wire; when the liquid flow rate in the tower body is greater than the flow rate threshold, the linear packing is set to the twisted composite wire. The flow rate threshold is 86 to 93 mL / min (preferably 90 mL / min).

[0011] The composite wire in a single composite wire or a twisted-pair composite wire is a composite wire made of stainless steel wire coated with an organic coating.

[0012] Preferably, the ratio of the number of linear packing elements to the diameter of the tower body is 18-22 elements: 26-35 mm.

[0013] Preferably, the diameter of the line filler is 0.5 to 2 mm.

[0014] Preferably, the organic coating covering the stainless steel wire in the composite wire is a polytetrafluoroethylene layer.

[0015] Preferably, the stainless steel wire has a diameter of 0.2 to 0.6 mm and the organic coating has a thickness of 0.15 to 0.8 mm.

[0016] Preferably, the top of all the linear packing is connected to the top of the tower, and the top of the tower applies tension to the linear packing to keep it in a straight and taut state.

[0017] Preferably, the distance between each line filler and the adjacent line filler is equal or substantially equal.

[0018] Preferably, the diameter of the single composite wire is 0.5 to 1.6 mm, and the diameter of the twisted pair composite wire is 0.8 to 2.1 mm.

[0019] Preferably, the light phase outlet is located above the heavy phase inlet, and the orifice distributor is located below the heavy phase inlet; the heavy phase outlet is located below the light phase inlet, and the line distributor is connected to the light phase inlet, so that the light phase discharged through the light phase inlet flows upward through the line distributor.

[0020] Preferably, the vertical distance between the line distributor and the orifice distributor is L, and the inner diameter of the tower body is D, where L and D satisfy L / D = 20 to 95.

[0021] Preferably, both the line distributor and the orifice distributor are provided with support holes, through which the line distributor and the orifice distributor are connected to the tower body.

[0022] The technical effects of this invention are as follows:

[0023] 1. The present invention sets up a specific linear packing. Based on the exploration of the motion behavior and mass transfer results of dispersed phase droplets on the packing surface, the setting of the linear packing and the selection of specific materials in the present invention give full play to the role of droplet surface tension and wettability. Therefore, the liquid film type extraction tower set up in the present invention can effectively realize the mass transfer of dispersed phase liquid in the form of linear motion.

[0024] 2. This invention specifically sets the density of the linear packing material. Research has shown that too little linear packing material (i.e., too low linear density) will cause the liquid to aggregate and form large droplets when the dispersed phase flows along the line, reducing the specific surface area for mass transfer and thus reducing the overall mass transfer efficiency. On the other hand, if there is too much linear packing material (i.e., too high linear density), when the liquid film moves along the line, the droplets on adjacent lines will collide and coalesce to form large droplets, reducing the mass transfer efficiency. Therefore, this invention, through inventive research, sets the linear density within a specific range. By limiting this range, it can be ensured that when the dispersed phase flows along the line, while maintaining the mass transfer efficiency of a single line, the liquid films on adjacent lines are separated and independent of each other, thus ensuring stable mass transfer of the dispersed phase fluid in a single line.

[0025] Meanwhile, this invention sets the linear packing to a straight line at all times (i.e., a straight line with tension). This setting can eliminate the axial backmixing problem of the dispersed liquid. Axial backmixing is a major problem in reducing mass transfer in extraction towers, while liquid film extraction towers can greatly reduce or even completely eliminate axial backmixing. If the linear packing is bent, it will cause the liquid to collide and coalesce into large droplets, reducing mass transfer efficiency. Therefore, this invention sets the linear packing to a straight line at all times. This setting is closely coordinated with the overall design of this invention.

[0026] Meanwhile, this invention sets different forms of linear packing within different flow ranges of the material in the tower. When the flow range is less than the flow threshold (e.g., 0 to about 90 mL / min), extraction using a single line can ensure mass transfer and better perform the function of eliminating the axial back-mixing problem of the dispersed liquid. However, when the flow rate increases to a value greater than the flow threshold (e.g., greater than about 90 mL / min), the mass transfer advantage of a single line decreases due to the increased flow rate. At this time, the line structure is set as a double spiral. Due to the specific twisted spiral shape, larger droplets can spread on the spiral line, thereby increasing the mass transfer area, enhancing the turbulence and solute diffusion inside the liquid film, and ultimately further improving the mass transfer effect compared to a single line packing within this flow range.

[0027] Meanwhile, by setting up a hole distributor and a line distributor, as well as straightening the line filler, this invention ensures that the line filler can be evenly separated and straightened.

[0028] In other words, this invention achieves the overall linear movement of the dispersed phase by specifically arranging and setting the packing material. This technology not only achieves the absence of flooding in the dispersed liquid within the extraction tower, but also has a significant advantage in extraction efficiency compared to traditional packed extraction towers. It not only increases the specific surface area for mass transfer, but also improves the mass transfer efficiency by 30-70%. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the high-efficiency liquid film extraction tower of the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of a hole distributor according to one embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of a line distributor according to one embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram of the structure of the twisted-pair composite cable of the present invention.

[0033] Wherein: 01-Tower top, 02-Tower body, 03-Tower bottom, 04-Light phase outlet, 05-Heavy phase inlet, 06-Light phase inlet, 07-Heavy phase outlet, 08-Line packing; 09-Orifice distributor, 10-Line distributor, 11-Support transverse plate, 12-Through hole of the through-hole section, 13-Support hole, 14-Gap of orifice distributor, 15-Transverse plate, 16-Line connector, 17-Gap of line distributor, 18-Organic coating, 19-Stainless steel wire. Detailed Implementation

[0034] The process technology solution of the present invention will be further described below with reference to embodiments and accompanying drawings. The orientations mentioned in this specification refer to the orientation of the present invention during normal operation, and do not limit its orientation during storage and transportation; they represent only relative positional relationships, not absolute positional relationships. Unless otherwise specifically described, each feature is merely one example of a series of equivalent or similar features. These embodiments are merely for the purpose of aiding understanding the present invention, and those skilled in the art should understand that they are only for illustrative purposes and should not be considered as specific limitations on the present invention.

[0035] Example 1

[0036] like Figures 1-3 As shown, the high-efficiency liquid film extraction tower of this embodiment includes a tower body, a tower bottom, a tower top, and a packing component inside the tower.

[0037] like Figure 1 The tower base is located below the tower body, and the tower top is located above the tower body. The tower base, tower body, and tower top are interconnected, and the diameters of the tower base and tower top are larger than the diameter of the tower body. A light phase outlet and a heavy phase inlet are provided on the side wall of the tower top, and a light phase inlet and a heavy phase outlet are provided on the side wall of the tower base.

[0038] The packing components inside the tower include a linear distributor, a perforated distributor, and linear packing; such as Figure 3 The line distributor shown is located at the junction of the tower bottom and the tower body. The line distributor includes a horizontal disc and line connecting posts. The outer edge of the horizontal disc connects to the inner edge of the tower bottom. Twenty line connecting posts are vertically arranged on the top of the horizontal disc. Gaps are provided on the horizontal disc to allow material to flow vertically. Figure 2 The hole distributor shown includes a supporting horizontal plate and a through-hole section. The outer edge of the supporting horizontal plate is connected to the inner edge of the upper part of the tower body. The through-hole section is located in the inner circle of the supporting horizontal plate and has multiple through holes. A gap is provided between the supporting horizontal plate and the through-hole section. The through holes allow the linear packing material to pass through, and the gap in the hole distributor allows the material to flow vertically. There are 20 linear packing materials, and the top of all the linear packing materials is connected to the top of the tower. The bottom of each linear packing material is connected to the 20 linear connecting posts of the linear distributor. The linear packing material passes through the through holes in the hole distributor. The linear packing material is vertically arranged in a straight line within the tower body.

[0039] This embodiment is based on laboratory measurements. The extraction tower in this embodiment has an inner diameter of 3 cm, and the packing material is a single composite wire. The stainless steel wire in this embodiment has a diameter of 0.58 mm, the organic coating thickness of the polytetrafluoroethylene is 0.21 mm, the diameter of each composite wire is 1 mm, and 20 composite wires are used. The cross-sectional area of ​​the tower's inner diameter is 15 × 15π mm. 2 The cross-sectional area of ​​the 20 wires is 5π mm. 2The linear density is 2.2%.

[0040] The organic phase loaded with phenol was back-extracted using the liquid film extraction tower of the above embodiment. The flow rate of the organic phase in the tower was 25 mL / min, which was less than the set flow rate threshold, and the back-extraction rate was measured to be 80%.

[0041] Example 2

[0042] like Figures 1-4 As shown, the high-efficiency liquid film extraction tower of this embodiment includes a tower body, a tower bottom, a tower top, and a packing component inside the tower.

[0043] like Figure 1 The tower bottom is located below the tower body, and the tower top is located above the tower body. The tower bottom, tower body, and tower top are interconnected, and the diameters of the tower bottom and tower top are larger than the diameter of the tower body. A light phase outlet and a heavy phase inlet are provided on the side wall of the tower top, and a light phase inlet and a heavy phase outlet are provided on the side wall of the tower bottom. The packing components inside the tower include a linear distributor, a perforated distributor, and linear packing. The linear distributor is located at the junction of the tower bottom and the tower body. The linear distributor includes a transverse disc and linear connecting columns. The outer edge of the transverse disc connects to the inner edge of the bottom of the tower body. Fifteen linear connecting columns are vertically arranged on the top of the transverse disc. Gaps are provided on the transverse disc for material to flow vertically. The perforated distributor includes a supporting transverse disc and a through-hole. The outer edge of the supporting transverse disc connects to the inner edge of the upper part of the tower body. The through-hole is located on the inner circle of the supporting transverse disc. The tower has multiple through holes (more than 15 through holes can be provided, with the remaining holes left empty). There is a gap between the support plate and the through hole section. The through holes allow the linear packing material to pass through, and the gaps on the orifice distributor allow the material to flow up and down. There are 15 linear packing materials, and the top of all the linear packing materials is connected to the top of the tower. The bottom of each linear packing material is connected to the 15 linear connecting posts of the linear distributor. The linear packing material passes through the orifice distributor through the through holes. The linear packing material is vertically arranged in a straight line within the tower body.

[0044] This embodiment is based on laboratory measurements. The extraction tower in this embodiment has an inner diameter of 3 cm, the packing material is twisted-pair composite wire, the stainless steel wire diameter is 0.33 mm, the organic coating thickness of the polytetrafluoroethylene is 0.175 mm, the diameter of a single twisted-pair composite wire is 1.36 mm, and 15 wires are used. The cross-sectional area of ​​the tower's inner diameter is 15 × 15π mm. 2 The cross-sectional area of ​​the 15 wires is approximately 6.936π mm. 2 The linear density is 3.1%.

[0045] The organic phase loaded with phenol was back-extracted using the liquid film extraction tower of the above embodiment. The liquid flow rate in the tower was 100 mL / min, which was greater than the set flow rate threshold, and the back-extraction rate was measured to be 90%.

[0046] Example 3

[0047] This embodiment is a setup for industrial testing, such as... Figures 1-4 As shown, the other settings in this embodiment are the same as in Embodiment 2, except that the dimensions of the extraction tower are normal industrial operating dimensions. In this embodiment, the inner diameter of the extraction tower is 20cm, the height is 15m, the wire packing is twisted composite wire, the diameter of the stainless steel wire in this embodiment is 0.5mm, the thickness of the organic coating of polytetrafluoroethylene is 0.175mm, the diameter of a single twisted composite wire is 1.7mm, and 430 wires are provided. The cross-sectional area of ​​the inner diameter of the tower is 100×100πmm². 2 The cross-sectional area of ​​430 wires is approximately 310π mm. 2 The linear density is approximately 3.1%.

[0048] The organic phase loaded with phenol was back-extracted using a liquid film extraction tower in this embodiment. The liquid flow rate in the tower was 100 mL / min, which was greater than the set flow rate threshold, and the back-extraction rate was measured to be 92%.

[0049] Comparative Example 1

[0050] In this comparative example, an existing spray tower was used to back-extract the same phenol-loaded organic phase as in Example 1. Under the same conditions as in Example 1, the back-extraction rate was measured to be 47%.

[0051] Comparative Example 2

[0052] In this comparative example, an existing Pall ring packed tower was used to back-extract the same organic phase loaded with phenol as in Example 2. Under the same conditions as in Example 2, the back-extraction rate was measured to be 69%.

[0053] Comparative Example 3

[0054] The other settings of this comparative example are the same as those of Example 2, except that the number of twisted-pair composite wires is set to 20, and the linear density is 4.1% (not within the linear density range defined by this invention). The organic phase loaded with phenol is back-extracted using the liquid film extraction tower of this comparative example, and the back-extraction rate is measured to be 72%. Except for the linear density, everything else in this comparative example is the same as in Example 2, but the measured back-extraction rate is significantly lower than that of Example 2. This is because with too much wire packing, when the liquid film moves on the wire, the droplets of adjacent wires collide and coalesce into larger droplets, thereby reducing the mass transfer efficiency and thus affecting the back-extraction rate.

[0055] Comparative Example 4

[0056] The other settings of this comparative example are the same as those of Example 2, except that the number of twisted-pair composite wires is set to 1, and the linear density is 0.2% (not within the linear density range defined by this invention). The organic phase loaded with phenol is back-extracted using the liquid film extraction tower of this comparative example, and the back-extraction rate is measured to be 24%. Except for the linear density, this comparative example is the same as Example 2, but the measured extraction and back-extraction rates are significantly lower than those of Example 2. This is because with too few wire fillers, when the liquid film moves along the line, the droplets from a single twisted pair form large droplets due to excessive flow, thus reducing mass transfer efficiency. Comparative Examples 3 and 4 illustrate that the various settings of this invention are closely coordinated, and the linear density range and the setting of the straight line are coordinated.

[0057] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A high-efficiency liquid film extraction tower, characterized in that, This includes the tower body, tower bottom, tower top, and internal packing components; The tower base is located below the tower body, and the tower top is located above the tower body. The tower base, tower body, and tower top are interconnected, and the diameters of the tower base and tower top are larger than the diameter of the tower body. A light phase outlet and a heavy phase inlet are provided on the side wall at the top of the tower, and a light phase inlet and a heavy phase outlet are provided on the side wall at the bottom of the tower. The tower packing components include a linear distributor, a perforated distributor, and linear packing. The linear distributor is located at or above the junction of the tower bottom and the tower body. The linear distributor includes a horizontal disc and linear connecting columns. The outer edge of the horizontal disc connects to the inner edge of the bottom of the tower body. Multiple linear connecting columns are vertically positioned on top of the horizontal disc. Gaps are provided on the horizontal disc to allow material to flow vertically. The perforated distributor includes a supporting horizontal disc and a through-hole. The outer edge of the supporting horizontal disc connects to the inner edge of the upper part of the tower body. The through-hole is located on the supporting horizontal disc... The inner circumference of the support plate has multiple through holes in the through-hole section, and a gap is provided between the support plate and the through-hole section. The through holes allow the linear packing material to pass through, and the gap on the orifice distributor allows the material to flow up and down. There are multiple linear packing materials, and the top of all the linear packing materials is connected to the top of the tower. The bottom of each linear packing material is connected to multiple linear connecting posts of the linear distributor. The linear packing material passes through the orifice distributor through the through holes. The linear packing material is vertically arranged in a straight line within the tower body. The linear packing has a linear density of 1.5% to 3.5% within the tower. Each piece of the linear packing is a single composite wire or a twisted composite wire made of two composite wires wound together. When the liquid flow rate in the tower is less than the flow rate threshold, the linear packing is set to the single composite wire; when the liquid flow rate in the tower is greater than the flow rate threshold, the linear packing is set to the twisted composite wire. The flow rate threshold is 86 to 93 mL / min. The composite wire in a single composite wire or a twisted-pair composite wire is a composite wire made of stainless steel wire coated with an organic coating.

2. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The ratio of the number of linear packing elements to the inner diameter of the tower body is 18-22 elements: 26-35 mm.

3. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The diameter of the line filler is 0.5 to 2 mm.

4. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The organic coating on the outside of the stainless steel wire in the composite line is a polytetrafluoroethylene layer.

5. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The stainless steel wire has a diameter of 0.2 to 0.6 mm, and the organic coating has a thickness of 0.15 to 0.8 mm.

6. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The top of all the linear packing material is connected to the top of the tower, and the top of the tower applies tension to the linear packing material to keep it in a straight and taut state at all times.

7. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The distance between each filler bar and its adjacent filler bar is equal or substantially equal.

8. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The diameter of the single composite wire is 0.5 to 1.6 mm, and the diameter of the twisted pair composite wire is 0.8 to 2.1 mm.

9. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The light phase outlet is located above the heavy phase inlet, and the orifice distributor is located below the heavy phase inlet; the heavy phase outlet is located below the light phase inlet, and the line distributor is connected to the light phase inlet, so that the light phase discharged through the light phase inlet flows upward through the line distributor.

10. The high-efficiency liquid film extraction tower according to claim 1, characterized in that, The vertical distance between the line distributor and the orifice distributor is L, and the inner diameter of the tower body is D, where L and D satisfy L / D = 20 to 95.

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