A composite sieve plate extraction column and its application in an extraction system with low interfacial tension

Abstract

The present invention discloses a composite sieve plate extraction column and its application in an extraction system with low interfacial tension. It is composed of alternating stirring sections and clarification sections. A composite sieve plate A is provided at the upper end of the stirring section, and a composite sieve plate B is provided at the lower end. The two sides of the composite sieve plates A and B are made of two materials with different hydrophilic and hydrophobic properties, one side being a hydrophilic material and the other side being a hydrophobic material. When the oil phase in the extraction column is the dispersed phase, the hydrophilic material side faces the clarification section, and the hydrophobic material side faces the stirring section. When the water phase in the extraction column is the dispersed phase, the hydrophilic material side faces the stirring section, and the hydrophobic material side faces the clarification section. When treating an extraction system with low interfacial tension, this composite sieve plate extraction column can achieve the cycle of "dispersion - coalescence - re - dispersion" of the dispersed - phase droplets, is not easily emulsified, has a wide operating range, a large equipment throughput, and a significantly improved extraction efficiency, solving the problems of easy emulsification, difficult coalescence, small throughput, and low efficiency in the extraction system with low interfacial tension.

Description

Technical Field

[0001] The present invention belongs to the field of extraction and separation, and relates to a compound sieve plate extraction column and its application in an extraction system with low interfacial tension. Background Art

[0002] In the process of chemical production, many extraction processes involve systems with low interfacial tension, such as the extraction and separation of higher alcohol-hydrocarbon mixtures, the extraction system for lubricating oil refining, the extraction of aromatic hydrocarbons with sulfolane, the extraction of erythromycin with n-butyl acetate, and the solvent extraction of copper ore. Systems with low interfacial tension are prone to emulsification during the extraction process, resulting in low flux and poor extraction efficiency, which also has a greater impact on product quality and yield. There is an urgent need for new extraction equipment to solve the problems of easy emulsification and low flux, so as to improve extraction efficiency and product quality.

[0003] Zhu Shenlin et al. (Petroleum Refining, 1993, 24(4): 8-13) studied the mass transfer characteristics of a low interfacial tension system in a sieve plate extraction column. Using a n-butanol-succinic acid-water system with low interfacial tension, the average droplet diameter and plate efficiency were studied in a large sieve hole plate extraction column, providing a reference basis for the optimization of the sieve plate column in the extraction and separation process of aromatic hydrocarbons with sulfolane. At the same time, application examples of large sieve hole sieve plate columns in industry were given, increasing the daily processing capacity of the original industrial extraction column for extracting heavy aromatic hydrocarbons from diesel with dimethyl sulfoxide as the solvent by 15%, improving economic benefits. However, the large sieve hole sieve plate extraction column has serious axial backmixing, especially for systems with small density differences, which is not conducive to the improvement of extraction efficiency.

[0004] Cui Jianhua et al. (CN205699575U) disclosed a new type of composite extraction sieve plate. The sieve plate body has two opposite surfaces, which are respectively coated with a hydrophilic material layer and a hydrophobic material layer. The placement direction of the sieve plate surface material is determined by the characteristics of the dispersed phase, so that the dispersed phase can contact the compatible surface for the first time, thereby promoting coalescence and improving extraction efficiency. This composite sieve plate has a certain effect on reducing the emulsification phenomenon in the extraction system with low interfacial tension. However, due to the coalescence of the dispersed phase on the compatible surface, the mass transfer specific surface area decreases, and at the same time, the problem of low equipment flux cannot be solved. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a compound sieve plate extraction column and a method for its application in an extraction system with low interfacial tension.

[0006] The present invention provides a composite sieve plate extraction column, which is alternately composed of a stirring section and a clarification section along the height direction of the column. A composite sieve plate A is provided at the upper end of the stirring section, and a composite sieve plate B is provided at the lower end. The two sides of the composite sieve plate A and the composite sieve plate B are made of two different hydrophilic and hydrophobic materials, one side is a hydrophilic material and the other side is a hydrophobic material. When the oil phase in the extraction column is the dispersed phase, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the clarification section, and the hydrophobic material surfaces face the stirring section. When the water phase in the extraction column is the dispersed phase, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the stirring section, and the hydrophobic material surfaces face the clarification section.

[0007] According to a preferred embodiment of the present invention, the hydrophilic material is a metal material such as stainless steel, aluminum or titanium, and its thickness is 0.5 - 10 mm.

[0008] According to a preferred embodiment of the present invention, the hydrophobic material is polytetrafluoroethylene, polyethylene or polypropylene, and its thickness is 0.5 - 10 mm.

[0009] According to a preferred embodiment of the present invention, the side of the composite sieve plate A and the composite sieve plate B facing the stirring section is provided with openings, and the opening method is uniform opening, the hole diameter is 1.0 - 4.0 mm, and the opening ratio is 5 - 30%.

[0010] According to a preferred embodiment of the present invention, the side of the composite sieve plate A and the composite sieve plate B facing the clarification section is provided with openings or slots at the positions corresponding to the openings on the side facing the stirring section, the hole diameter is 4.0 - 10.0 mm, and the width of the slot is not less than the hole diameter of the opening on the side facing the stirring section and not more than 10.0 mm.

[0011] According to a preferred embodiment of the present invention, the side of the composite sieve plate A and the composite sieve plate B facing the clarification section adopts a combination of slotting and opening at the positions corresponding to the openings on the side facing the stirring section, the hole diameter is 4.0 - 10.0 mm, and the width of the slot is not less than the hole diameter of the opening on the side facing the stirring section and not more than 10.0 mm.

[0012] According to an alternative embodiment of the present invention, the side of the composite sieve plate A facing the clarification section adopts the method of external slotting and internal opening, and the side of the composite sieve plate B facing the clarification section adopts the method of internal slotting and external opening.

[0013] According to an alternative embodiment of the present invention, the side of the composite sieve plate A facing the clarification section adopts the method of internal slotting and external opening, and the side of the composite sieve plate B facing the clarification section adopts the method of external slotting and internal opening.

[0014] The present invention also provides an application of the above-mentioned composite sieve plate extraction column in the extraction of a low interfacial tension extraction system. The low interfacial tension extraction system refers to a system with an interfacial tension less than 3 mN / m. Typically but not limited to, such as a lubricating oil refining extraction system, a sulfolane aromatic hydrocarbon extraction system, a n-butanol - succinic acid - water system, a cyclohexane - isopropanol - water system, and systems such as heptanol - undecane - ethanol - water, octanol - dodecane - ethanol - water, nonanol - tridecane - ethanol - water, decanol - tetradecane - ethanol - water, etc. in the extraction and separation of high-carbon alcohol hydrocarbon mixtures.

[0015] The advantages of the present invention are as follows: The sieve plate material surface with good wettability to the dispersed phase faces the stirring section, which is beneficial for the adsorption and coalescence of the dispersed phase droplets on the sieve plate surface in the stirring section. At the same time, when the droplets after adsorption and coalescence leave the sieve plate and enter the clarification section, they are affected by the sieve plate material with poor wettability facing the clarification section and its larger openings or wider slots, and can not only leave smoothly, but also be redispersed into small droplets again. Therefore, when the composite sieve plate extraction column treats a low interfacial tension extraction system, it can realize the cycle of "dispersion - coalescence - redispersion" of the dispersed phase droplets, is not easily emulsified, has a wide operation range, a large equipment throughput, and a significantly improved extraction efficiency, solving the problems of easy emulsification, difficult coalescence, small throughput, and low efficiency in the low interfacial tension extraction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a composite sieve plate extraction column.

[0017] Figure 2 is a schematic diagram of a composite sieve plate material.

[0018] Figure 3 and Figure 4 is a schematic diagram of the grooving method.

[0019] Figure 5 is a schematic diagram of external grooving and internal perforation.

[0020] Figure 6 is a schematic diagram of internal grooving and external perforation. DETAILED DESCRIPTION OF THE INVENTION

[0021] Such as Figure 1 and Figure 2As shown in the figure, the present invention provides a composite sieve plate extraction column, which is composed of alternating stirring sections and clarification sections along the tower height direction. A composite sieve plate A is provided at the upper end of the stirring section, and a composite sieve plate B is provided at the lower end. The two sides of the composite sieve plate A and the composite sieve plate B are made of two different hydrophilic and hydrophobic materials, one side is a hydrophilic material and the other side is a hydrophobic material. When the oil phase is the dispersed phase in the extraction column, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the clarification section, and the hydrophobic material surfaces face the stirring section. When the water phase is the dispersed phase in the extraction column, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the stirring section, and the hydrophobic material surfaces face the clarification section.

[0022] The stirring section in the composite sieve plate extraction column is the section where a stirring device (such as a stirring paddle) is set, and the clarification section is the section where no stirring paddle is set. In the present invention, the stirring section and the clarification section are divided by a composite sieve plate. An opening, slotted or slotted hole composite structure for connecting the upper and lower sections is set on the composite sieve plate to allow the liquid to flow through. The stirring paddles in each stirring section can be driven by a stirring shaft driven by the same belt to rotate synchronously, or other stirring driving methods can also be adopted. The heights of the stirring section and the clarification section can be selected according to the characteristics of the system, generally not exceeding the diameter of the extraction column. The number of sections of the stirring section and the clarification section is selected according to the characteristics of the system and the extraction effect to be achieved.

[0023] Among them, the hydrophilic material can be selected as metal materials such as stainless steel, aluminum or titanium, and its thickness is 0.5-10 mm. The hydrophobic material can be polytetrafluoroethylene, polyethylene or polypropylene, and its thickness is 0.5-10 mm. An opening is set on the side of the composite sieve plate A and the composite sieve plate B facing the stirring section in the present invention. The opening method is uniform opening, the hole diameter is 1.0-4.0 mm, and the opening ratio is 5-30%.

[0024] When the water phase is the dispersed phase in the extraction column, in the embodiment of the present invention, the side of the composite sieve plate A and the composite sieve plate B facing the stirring section is the hydrophilic material surface, and this surface is uniformly opened according to the aforementioned opening requirements. The hydrophobic material surface is opened or slotted at the corresponding opening positions of the hydrophilic material surface. The hole diameter is 4.0-10.0 mm, the groove width is not less than the hole diameter of the opening on the hydrophilic material surface and not more than 10.0 mm. The slotted method is as Figure 3 or Figure 4 shown. Among them Figure 3 is an arc-shaped groove, Figure 4 is a linear groove.

[0025] Furthermore, when the hydrophilic material surface is uniformly opened, the hydrophobic material surface adopts a combination of slotted and opening methods at the corresponding opening positions of the hydrophilic material surface. The hole diameter is 4.0-10.0 mm, the groove width is not less than the hole diameter of the opening on the hydrophilic material surface and not more than 10.0 mm. The slotted and opening methods are as Figure 5 or Figure 6 shown.

[0026] Further, when the hydrophobic material surface adopts a combination of grooving and perforating, an optional implementation manner is as follows: the hydrophobic material surface of the composite sieve plate A adopts the manner of grooving on the outside and perforating on the inside, as Figure 5 shown, and the hydrophobic material surface of the composite sieve plate B adopts the manner of grooving on the inside and perforating on the outside, as Figure 6 shown.

[0027] When the hydrophobic material surface adopts a combination of grooving and perforating, another optional implementation manner is as follows: the hydrophobic material surface of the composite sieve plate A adopts the manner of grooving on the inside and perforating on the outside, as Figure 6 shown, and the hydrophobic material surface of the composite sieve plate B adopts the manner of grooving on the outside and perforating on the inside, as Figure 5 shown.

[0028] When the oil phase in the extraction column is the dispersed phase, in the implementation manner of the present invention, the surfaces of the composite sieve plates A and B facing the stirring section are hydrophobic material surfaces, and this surface is uniformly perforated according to the aforementioned perforating requirements. When uniformly perforating, the hydrophilic material surface is perforated or grooved at the positions corresponding to the perforations on the hydrophobic material surface. The hole diameter is 4.0 - 10.0 mm, and the groove width is not less than the hole diameter of the perforations on the hydrophobic material surface and not greater than 10.0 mm. The grooving manner is as Figure 3 or Figure 4 shown.

[0029] Further, when the hydrophobic material surface is uniformly perforated, the hydrophilic material surface adopts a combination of grooving and perforating at the positions corresponding to the perforations on the hydrophobic material surface. The hole diameter is 4.0 - 10.0 mm, and the groove width is not less than the hole diameter of the perforations on the hydrophobic material surface and not greater than 10.0 mm. The grooving and perforating manners are as Figure 5 or Figure 6 shown.

[0030] Further, when the hydrophilic material surface adopts a combination of grooving and perforating, an optional implementation manner is as follows: the hydrophilic material surface of the composite sieve plate A adopts the manner of grooving on the outside and perforating on the inside, as Figure 5 shown, and the hydrophilic material surface of the composite sieve plate B adopts the manner of grooving on the inside and perforating on the outside, as Figure 6 shown.

[0031] When the hydrophilic material surface adopts a combination of grooving and perforating, another optional implementation manner is as follows: the hydrophilic material surface of the composite sieve plate A adopts the manner of grooving on the inside and perforating on the outside, as Figure 6 shown, and the hydrophilic material surface of the composite sieve plate B adopts the manner of grooving on the outside and perforating on the inside, as Figure 5 shown.

[0032] Example 1

[0033] AsFigure 1 The composite sieve plate extraction tower shown has a diameter of 50 mm, with a total of 3 stirring sections and 4 clarification sections. The stirring section height is 35 mm, and the clarification section height is 50 mm. The hydrophilic material of the composite sieve plate A and the composite sieve plate B is stainless steel with a thickness of 1.0 mm. The hydrophobic material of the composite sieve plate A and the composite sieve plate B is polytetrafluoroethylene with a thickness of 1.0 mm. During installation, the hydrophobic material surface of the composite sieve plate A and the composite sieve plate B is facing the stirring section. Small holes with a diameter of 3.0 mm are evenly opened on the hydrophobic material surface, and the porosity is 10%. The hydrophilic material surface of the composite sieve plate A is grooved on the outside with a groove width of 3.0 mm, and holes are opened on the inside with a hole diameter of 4.0 mm. The hydrophilic material surface of the composite sieve plate B is grooved on the inside with a groove width of 3.0 mm, and holes are opened on the outside with a hole diameter of 4.0 mm. The low interfacial tension n-butanol-succinic acid-water system (interfacial tension of 0.753 mN / m) was used as the research object. A 5% n-butanol solution of succinic acid was pumped into the light phase inlet as the dispersed phase, and pure water was pumped into the heavy phase inlet as the continuous phase. The solvent ratio was 1. When the rotation speed was 130 rpm and the total flow rate of the two phases was 60 mL / min, the theoretical number of extraction stages was 1.21, and the maximum flux of the extraction tower was 7.2 m 3 / (m 2 ·hr).

[0034] Example 2

[0035] like Figure 1 The composite sieve plate extraction tower shown has a diameter of 50 mm, with a total of 3 stirring sections and 4 clarification sections. The stirring section height is 35 mm, and the clarification section height is 50 mm. The hydrophilic material of the composite sieve plate A and the composite sieve plate B is stainless steel with a thickness of 1.0 mm. The hydrophobic material of the composite sieve plate A and the composite sieve plate B is polytetrafluoroethylene with a thickness of 1.0 mm. Both the composite sieve plate A and the composite sieve plate B have the hydrophobic material surface facing the stirring section, and small holes with a diameter of 3.0 mm are uniformly opened on the hydrophobic material surface, with an opening rate of 10%. The hydrophilic material surface of the composite sieve plate A is grooved internally with a groove width of 3.0 mm, and is holed externally with a hole diameter of 4.0 mm. The hydrophilic material surface of the composite sieve plate B is grooved externally with a groove width of 3.0 mm, and is holed internally with a hole diameter of 4.0 mm. The low interfacial tension n-butanol-succinic acid-water system (interfacial tension of 0.753 mN / m) was used as the research object. A 5% n-butanol solution of succinic acid was pumped into the light phase inlet as the dispersed phase, and pure water was pumped into the heavy phase inlet as the continuous phase. The solvent ratio was 1. When the rotation speed was 130 rpm and the total flow rate of the two phases was 60 mL / min, the theoretical extraction stage was 1.13, and the maximum flux of the extraction tower was 7.2 m 3 / (m 2 ·hr).

[0036] Example 3

[0037] likeFigure 1 The shown compound sieve plate extraction column has a diameter of 50 mm, with a total of 3 stirring sections and 4 clarification sections. The height of the stirring section is 35 mm, and the height of the clarification section is 50 mm. The hydrophilic materials of compound sieve plate A and compound sieve plate B are stainless steel with a thickness of 0.5 mm, and the hydrophobic materials are polytetrafluoroethylene with a thickness of 1.0 mm. Both compound sieve plate A and compound sieve plate B face the hydrophilic material surface towards the stirring section, and small holes with a diameter of 3.0 mm are evenly opened on the hydrophilic material surface, with an opening rate of 10%. The hydrophobic material surface of compound sieve plate A has internal grooves with a width of 3.0 mm and external holes with a diameter of 4.0 mm. The hydrophobic material surface of compound sieve plate B has external grooves with a width of 3.0 mm and internal holes with a diameter of 4.0 mm. Taking the n-butanol - succinic acid - water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object, a n-butanol solution with a mass fraction of 5% of succinic acid is pumped into from the light phase inlet as the continuous phase, and pure water is pumped into from the heavy phase inlet as the dispersed phase, with a solvent ratio of 1. When the rotational speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 1.17 stages, and the maximum flux of the extraction column is 10.8 m 3 / (m 2 ·hr).

[0038] Example 4

[0039] As Figure 1 shown, the compound sieve plate extraction column has a diameter of 100 mm, with a total of 6 stirring sections and 7 clarification sections. The height of the stirring section is 70 mm, and the height of the clarification section is 80 mm. The hydrophilic materials of compound sieve plate A and compound sieve plate B are titanium materials with a thickness of 1.0 mm, and the hydrophobic materials are polypropylene with a thickness of 0.5 mm. Both compound sieve plate A and compound sieve plate B face the hydrophobic material surface towards the stirring section, and small holes with a diameter of 1.0 mm are evenly opened on the hydrophobic material surface, with an opening rate of 30%. The hydrophilic material surface has grooves at the positions corresponding to the openings of the hydrophobic material surface, as Figure 3 shown, with a groove width of 1.5 mm. Taking the decanol - tetradecane - ethanol - water system with low interfacial tension (interfacial tension is 0.490 mN / m) as the research object, a tetradecane solution with a mass fraction of 50% of decanol is pumped into from the light phase inlet as the dispersed phase, and a 65% ethanol aqueous solution is pumped into from the heavy phase inlet as the continuous phase, with a solvent ratio of 3. When the rotational speed is 40 rpm and the total flow rate of the two phases is 200 mL / min, the extraction theoretical stage number is 2.13 stages, and the maximum flux of the extraction column is 7.9 m 3 / (m 2 ·hr).

[0040] Example 5

[0041] As Figure 1The shown compound sieve plate extraction column has a diameter of 100 mm, with a total of 6 stirring sections and 7 clarification sections. The height of the stirring section is 70 mm, and the height of the clarification section is 80 mm. The hydrophilic materials of compound sieve plate A and compound sieve plate B are titanium materials with a thickness of 1.0 mm. The hydrophobic materials of compound sieve plate A and compound sieve plate B are polypropylene with a thickness of 1.0 mm. Both compound sieve plate A and compound sieve plate B face the hydrophobic material surface towards the stirring section. The hydrophobic material surface is evenly opened with small holes having a diameter of 4.0 mm, and the hole opening rate is 5%. The hydrophilic material surface is grooved at the positions corresponding to the holes on the hydrophobic material surface, as Figure 4 shown, and the groove width is 10.0 mm. Taking the decanol - tetradecane - ethanol - water system with low interfacial tension (interfacial tension is 0.490 mN / m) as the research object, a tetradecane solution with a decanol mass fraction of 50% is pumped into the light phase inlet as the dispersed phase, and a 65% ethanol aqueous solution is pumped into the heavy phase inlet as the continuous phase. The solvent ratio is 3. When the rotation speed is 40 rpm and the total flow rate of the two phases is 200 mL / min, the extraction theoretical stage number is 2.21 stages, and the maximum flux of the extraction column is 8.2 m 3 / (m 2 ·hr).

[0042] Example 6

[0043] As Figure 1 shown, the compound sieve plate extraction column has a diameter of 100 mm, with a total of 6 stirring sections and 7 clarification sections. The height of the stirring section is 70 mm, and the height of the clarification section is 80 mm. The hydrophilic materials of compound sieve plate A and compound sieve plate B are aluminum sheets with a thickness of 1.0 mm. The hydrophobic materials of compound sieve plate A and compound sieve plate B are polyethylene with a thickness of 1.0 mm. Both compound sieve plate A and compound sieve plate B face the hydrophobic material surface towards the stirring section. The hydrophobic material surface is evenly opened with small holes having a diameter of 3.0 mm, and the hole opening rate is 10%. The hydrophilic material surface is opened with holes at the positions corresponding to the holes on the hydrophobic material surface, and the hole diameter is 6.0 mm. Taking the decanol - tetradecane - ethanol - water system with low interfacial tension (interfacial tension is 0.490 mN / m) as the research object, a tetradecane solution with a decanol mass fraction of 50% is pumped into the light phase inlet as the dispersed phase, and a 65% ethanol aqueous solution is pumped into the heavy phase inlet as the continuous phase. The solvent ratio is 3. When the rotation speed is 40 rpm and the total flow rate of the two phases is 200 mL / min, the extraction theoretical stage number is 2.35 stages, and the maximum flux of the extraction column is 7.6 m 3 / (m 2 ·hr).

[0044] Example 7

[0045] As Figure 1The shown compound sieve-plate extraction column has a diameter of 300 mm, with a total of 3 stirring sections and 4 clarification sections. The height of the stirring section is 120 mm, and the height of the clarification section is 180 mm. The hydrophilic materials of compound sieve-plate A and compound sieve-plate B are stainless steel with a thickness of 10.0 mm. The hydrophobic materials of compound sieve-plate A and compound sieve-plate B are polytetrafluoroethylene with a thickness of 10.0 mm. Both compound sieve-plate A and compound sieve-plate B face the hydrophobic material surface towards the stirring section. The hydrophobic material surface is evenly drilled with small holes having a diameter of 4.0 mm, and the hole opening rate is 10%. The hydrophilic material surface is drilled at the corresponding hole-opening positions of the hydrophobic material surface, and the hole diameter is 10.0 mm. Taking the cyclohexane-isopropanol-water system with low interfacial tension (interfacial tension is 1.396 mN / m) as the research object, a cyclohexane solution with an isopropanol mass fraction of 30% is pumped into the light-phase inlet as the dispersed phase, and pure water is pumped into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 24 rpm and the total flow rate of the two phases is 1500 mL / min, the extraction theoretical stage number is 1.32 stages, and the maximum flux of the extraction column is 12.9 m 3 / (m 2 ·hr).

[0046] Example 8

[0047] As Figure 1 The shown compound sieve-plate extraction column has a diameter of 300 mm, with a total of 3 stirring sections and 4 clarification sections. The height of the stirring section is 120 mm, and the height of the clarification section is 180 mm. The hydrophilic materials of compound sieve-plate A and compound sieve-plate B are stainless steel with a thickness of 4.0 mm. The hydrophobic materials of compound sieve-plate A and compound sieve-plate B are polytetrafluoroethylene with a thickness of 2.0 mm. Both compound sieve-plate A and compound sieve-plate B face the hydrophobic material surface towards the stirring section. The hydrophobic material surface is evenly drilled with small holes having a diameter of 2.0 mm, and the hole opening rate is 15%. The hydrophilic material surface is drilled at the corresponding hole-opening positions of the hydrophobic material surface, and the hole diameter is 4.0 mm. Taking the cyclohexane-isopropanol-water system with low interfacial tension (interfacial tension is 1.396 mN / m) as the research object, a cyclohexane solution with an isopropanol mass fraction of 30% is pumped into the light-phase inlet as the dispersed phase, and pure water is pumped into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 24 rpm and the total flow rate of the two phases is 1500 mL / min, the extraction theoretical stage number is 1.47 stages, and the maximum flux of the extraction column is 13.6 m 3 / (m 2 ·hr).

[0048] Comparative Example 1

[0049] Keep other parameters the same as in Example 1, and only select stainless steel for the two-sided materials of composite sieve plate A and composite sieve plate B. Using the n-butanol - succinic acid - water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object, pump a n-butanol solution with a mass fraction of 5% of succinic acid into the light-phase inlet as the dispersed phase, and pump pure water into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 0.88 stage, and the maximum throughput of the extraction column is 3.5 m 3 / (m 2 ·hr).

[0050] Comparative Example 2

[0051] Keep other parameters the same as in Example 1, and only select polytetrafluoroethylene for the two-sided materials of composite sieve plate A and composite sieve plate B. Using the n-butanol - succinic acid - water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object, pump a n-butanol solution with a mass fraction of 5% of succinic acid into the light-phase inlet as the dispersed phase, and pump pure water into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 0.92 stage, and the maximum throughput of the extraction column is 3.9 m 3 / (m 2 ·hr).

[0052] Comparative Example 3

[0053] Keep other parameters the same as in Example 1, and only change the material orientation so that the hydrophilic material surface faces the stirring section. Using the n-butanol - succinic acid - water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object, pump a n-butanol solution with a mass fraction of 5% of succinic acid into the light-phase inlet as the dispersed phase, and pump pure water into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 0.81 stage, and the maximum throughput of the extraction column is 3.0 m 3 / (m 2 ·hr).

[0054] Comparative Example 4

[0055] Keep other parameters the same as in Example 1, and only change the material orientation so that all the hydrophobic material surfaces face downwards. Using the n-butanol - succinic acid - water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object, pump a n-butanol solution with a mass fraction of 5% of succinic acid into the light-phase inlet as the dispersed phase, and pump pure water into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotational speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 0.89 stage, and the maximum throughput of the extraction column is 3.8 m3 / (m 2 ·hr).

[0056] Comparative Example 5

[0057] Keep other parameters the same as in Example 1, only change the pore-opening mode of the hydrophilic material to make the pore-opening modes of the hydrophilic material surface and the hydrophobic material surface exactly the same. Use the n-butanol-succinic acid-water system with low interfacial tension (interfacial tension is 0.753 mN / m) as the research object. Pump a n-butanol solution with a mass fraction of 5% of succinic acid into the light-phase inlet as the dispersed phase, and pump pure water into the heavy-phase inlet as the continuous phase. The solvent ratio is 1. When the rotation speed is 130 rpm and the total flow rate of the two phases is 60 mL / min, the extraction theoretical stage number is 1.07 stages, and the maximum throughput of the extraction column is 3.3 m 3 / (m 2 ·hr).

[0058] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A compound sieve plate extraction column, characterized in that It is alternately composed of a stirring section and a clarification section along the tower height direction. A composite sieve plate A is provided at the upper end of the stirring section, and a composite sieve plate B is provided at the lower end. Both sides of the composite sieve plate A and the composite sieve plate B are made of two materials with different hydrophilic and hydrophobic properties, one side is a hydrophilic material and the other side is a hydrophobic material. When the oil phase in the extraction tower is the dispersed phase, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the clarification section, and the hydrophobic material surfaces face the stirring section. When the water phase in the extraction tower is the dispersed phase, the hydrophilic material surfaces of the composite sieve plate A and the composite sieve plate B face the stirring section, and the hydrophobic material surfaces face the clarification section; Openings are provided on the side of the composite sieve plate A and the composite sieve plate B facing the stirring section. The opening method is uniform opening, the hole diameter is 1.0 - 4.0 mm, and the opening ratio is 5 - 30%; Openings or slots are provided on the side of the composite sieve plate A and the composite sieve plate B facing the clarification section at the positions corresponding to the openings on the side facing the stirring section. The hole diameter is 4.0 - 10.0 mm, and the slot width is not less than the hole diameter of the openings on the side facing the stirring section and not more than 10.0 mm.

2. The compound sieve plate extraction column according to claim 1, characterized in that The hydrophilic material is stainless steel, aluminum or titanium material, and its thickness is 0.5 - 10 mm.

3. The compound sieve plate extraction column according to claim 1, characterized in that The hydrophobic material is polytetrafluoroethylene, polyethylene or polypropylene, and its thickness is 0.5 - 10 mm.

4. The compound sieve plate extraction column according to claim 1, characterized in that, The side of the composite sieve plate A and the composite sieve plate B facing the clarification section adopts a combination of slotting and opening at the positions corresponding to the openings on the side facing the stirring section. The hole diameter is 4.0 - 10.0 mm, and the slot width is not less than the hole diameter of the openings on the side facing the stirring section and not more than 10.0 mm.

5. The compound sieve plate extraction column according to claim 4, characterized in that, The side of the composite sieve plate A facing the clarification section adopts the method of external slotting and internal opening, and the side of the composite sieve plate B facing the clarification section adopts the method of internal slotting and external opening.

6. The compound sieve plate extraction column according to claim 4, characterized in that, The side of the composite sieve plate A facing the clarification section adopts the method of internal slotting and external opening, and the side of the composite sieve plate B facing the clarification section adopts the method of external slotting and internal opening.

7. Application of the composite sieve plate extraction tower according to any one of claims 1 - 6 in the extraction of a low interfacial tension extraction system, where the low interfacial tension extraction system refers to a system with an interfacial tension less than 3 mN / m.

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