CN-117085636-B - Packing for liquid-liquid extraction tower and preparation method thereof

Abstract

The invention relates to a structured packing for a liquid-liquid extraction tower and a preparation method thereof, which realize high mass transfer specific surface area and high mass transfer efficiency when extracting the liquid-liquid extraction tower by arranging A-type packing and B-type packing and specifically setting the specific matching mode of the packing.

Inventors

• WANG YONG
• CHANG CHAO
• XU DONGBING
• TAN BOREN
• QI TAO

Assignees

• 中国科学院过程工程研究所

Dates

Publication Date

20260505

Application Date

20230714

Claims (10)

1. 1. The packing for the liquid-liquid extraction tower is characterized by being formed by pressing and arraying A-type packing and B-type packing, wherein the A-type packing is stainless steel wires with the diameter of 0.8-1.2 mm, the B-type packing is composite filaments formed by coating polytetrafluoroethylene outside the stainless steel wires with the diameter of 0.3-0.6 mm, the diameter of the composite filaments of the B-type packing is 0.85-1.25 mm, each A-type packing is bent into a zigzag shape, the angle of a bending angle is 15-60 degrees, the length of each bent section is 5-10 mm, each B-type packing is bent into a zigzag shape, the angle of the bending angle is 15-60 degrees, and the length of each bent section is 5-10 mm; the vertex of each zigzag angle of each A-type filler or B-type filler is connected with the vertex of each zigzag angle of the adjacent A-type filler or B-type filler to form a surface, the surface formed by the connected A-type filler or B-type filler is a pressed wavy curved surface, and the diameter of the wavy curved surface is 1-6 cm; The wave curved surface formed by the interconnection of the A-type packing is an A-type wave curved surface, the wave curved surface formed by the interconnection of the B-type packing is a B-type wave curved surface, a multi-layer overlapping layer of A-A-A is formed by overlapping and assembling a plurality of layers of A-type wave curved surfaces and a plurality of layers of B-type wave curved surfaces, a circulating multi-layer overlapping layer of a-B-B is formed by overlapping and assembling a plurality of layers of B-type wave curved surfaces, and the multi-layer overlapping layer of A-A-A, the circulating multi-layer overlapping layer of a-B-B and the multi-layer overlapping layer of B-B-B are overlapped and listed to form the packing for the liquid-liquid extraction tower.
2. 2. The packing for a liquid-liquid extraction column according to claim 1, wherein when the interfacial tension γ of the treated material is equal to or greater than an interfacial tension threshold, the angle of refraction of the type a packing is 45 to 60 °, the angle of refraction of the type B packing is 45 to 60 °, and when the interfacial tension γ of the treated material is less than an interfacial tension threshold, the angle of refraction of the type a packing is 15 to 45 °, the angle of refraction of the type B packing is 15 to 45 °, and the interfacial tension threshold is 18 to 26mn/m.
3. 3. The packing for a liquid-liquid extraction column according to claim 1, wherein the packing for a liquid-liquid extraction column is composed of a plurality of superimposed layers of B-B, a plurality of circulating multilayer superimposed layers of a-B and a plurality of multilayer superimposed layers of A-A in this order from top to bottom, and the ratio of the thicknesses of the respective layers is (0.8 to 1.1): (1.8 to 2.5): (7.5 to 8.5) of the multilayer superimposed layers of A-A-B of B-B.
4. 4. The packing for a liquid-liquid extraction column according to claim 1, wherein the packing for a liquid-liquid extraction column is composed of a plurality of superimposed layers of B-B, a plurality of circulating multilayer superimposed layers of a-B and a plurality of multilayer superimposed layers of A-A in this order from top to bottom, and the ratio of the thicknesses of the respective layers is (7.3 to 8.3): 1.6 to 2.3): 1.
5. 5. The packing for a liquid-liquid extraction column according to claim 1, wherein the diameter of the wavy curved surface is 2 to 5cm.
6. 6. The packing for a liquid-liquid extraction column according to claim 1, wherein the diameter of the wavy surface is 3 to 5cm when the interfacial tension γ of the treated material is equal to or greater than an interfacial tension threshold value, and the diameter of the wavy surface is 2 to 3cm when the interfacial tension γ of the treated material is less than an interfacial tension threshold value, and the interfacial tension threshold value is 18 to 26mn/m.
7. 7. A method for preparing a packing for a liquid-liquid extraction column, characterized in that the packing for a liquid-liquid extraction column is the packing for a liquid-liquid extraction column according to any one of claims 1 to 6, comprising the steps of: (1) Taking a stainless steel wire with the diameter of 0.3-0.6 mm, coating a polytetrafluoroethylene layer with the thickness of 0.2-0.3 mm outside the stainless steel wire to form a B-type filler of the composite filament, and then bending the formed B-type filler in a zigzag manner; (2) The method comprises the steps of (1) connecting the vertexes of each zigzag folded A-shaped filler obtained in the step with the vertexes of each zigzag folded corner of the adjacent A-shaped filler to form a surface, and (2) connecting the vertexes of each zigzag folded B-shaped filler obtained in the step with the vertexes of each zigzag folded corner of the adjacent B-shaped filler to form a surface; (3) The surface formed by the A-type filler obtained in the step (2) is subjected to surface pressing in a bidirectional manner on the upper surface and the lower surface by adopting a solid metal rod with the diameter of 1-6 cm to form a single-layer A-type wavy curved surface; (4) Performing multilayer superposition on the single-layer A-type wavy curved surface and the single-layer B-type wavy curved surface obtained in the step (3), and performing multilayer A-type wavy curved surface superposition assembly to form a multilayer superposition layer of A-A-A, multilayer A-type wavy curved surface superposition assembly and multilayer B-type wavy curved surface superposition assembly to form a circulating multilayer superposition layer of A-B-B, and multilayer B-B-type wavy curved surface superposition assembly to form a multilayer superposition layer of B-B; (5) And (3) respectively stacking the multi-layer overlapping layers of the A-A-A, the circulating multi-layer overlapping layers of the A-B-B and the multi-layer overlapping layers of the B-B obtained in the step (4) to obtain the packing product for the liquid-liquid extraction tower.
8. 8. The method according to claim 7, wherein in the step (5), a cyclic multilayer stack of a-B having a thickness of 3.2 to 3.8 is stacked over a multilayer stack of A-A having a thickness of 1.6 to 1.9, and then a multilayer stack of B-B having a thickness of 12 to 16 is stacked over the cyclic multilayer stack of a-B to form the packing for a liquid-liquid extraction column.
9. 9. The method according to claim 7, wherein in the step (5), a cyclic multilayer laminate of a-B having a thickness of 3.2 to 3.8 is stacked over a multilayer laminate of A-A having a thickness of 12 to 16, and then a multilayer laminate of B-B having a thickness of 1.6 to 1.9 is stacked over a cyclic multilayer laminate of a-B to form a packing for a liquid-liquid extraction column.
10. 10. The preparation method according to claim 7, wherein the diameter of the solid metal rod is 3-5 cm when the interfacial tension gamma of the processed material is equal to or greater than an interfacial tension threshold value, and the diameter of the solid metal rod is 2-3 cm when the interfacial tension gamma of the processed material is less than the interfacial tension threshold value, and the interfacial tension threshold value is 18-26 mn/m.

Description

Packing for liquid-liquid extraction tower and preparation method thereof Technical Field The invention belongs to the field of extraction, and particularly relates to a filler for a liquid-liquid extraction tower and a preparation method thereof. Background Liquid-liquid extraction is widely applied to the petroleum and chemical industries, and the filler is a core element of a filler extraction tower and can be divided into random packing and structured packing according to the form of the filler. The existing fillers are all gas-liquid rectification fillers, but liquid-liquid extraction is different from a gas-liquid rectification system, firstly, the requirements of extraction and rectification on the fillers are partially consistent, the fillers are required to have higher mass transfer efficiency, the filler layer needs to have larger porosity to avoid bias flow, channeling and the like, the liquid phase flows along the surface of the fillers in rectification, the fillers play a role of providing mass transfer area, the mass transfer in extraction occurs between a liquid drop group and a continuous phase, the role of the fillers is to control back mixing and realize the cycle process of breaking-coalescence-re-breaking of liquid drops, and the retention time of a disperse phase is influenced, so the filler with burrs in rectification is beneficial to mass transfer, but the filler is unfavorable in extraction. Disclosure of Invention Aiming at the technical problems, the invention aims to provide a filler for a liquid-liquid extraction tower and a preparation method thereof, so as to realize the crushing and aggregation processes of liquid drops, and meanwhile, the dispersed phase liquid drops are effectively aggregated based on the selection of filler materials, so that the aggregation mass transfer efficiency is improved. The method is realized by the following technical means: The packing for the liquid-liquid extraction tower is formed by pressing and arraying A-shaped packing and B-shaped packing, the A-shaped packing is a stainless steel wire with the diameter of 0.8-1.2 mm, the B-shaped packing is a composite filament formed by polytetrafluoroethylene coated outside the stainless steel wire with the diameter of 0.3-0.6 mm, the diameter of the composite filament of the B-shaped packing is 0.85-1.25 mm through a polytetrafluoroethylene coating layer, each A-shaped packing is bent into a zigzag shape, the angle of a bending angle is 15-60 degrees, the length of each bending section is 5-10 mm, each B-shaped packing is bent into a zigzag shape, the angle of the bending angle is 15-60 degrees, and the length of each bending section is 5-10 mm. The vertex of each zigzag angle of each A-type filler or B-type filler is connected with the vertex of each zigzag angle of the adjacent A-type filler or B-type filler to form a surface, the surface formed by the connected A-type filler or B-type filler is a pressed wavy curved surface, and the diameter of the wavy curved surface is 1-6 cm. The wave curved surface formed by the interconnection of the A-type packing is an A-type wave curved surface, the wave curved surface formed by the interconnection of the B-type packing is a B-type wave curved surface, a multi-layer overlapping layer of A-A-A is formed by overlapping and assembling a plurality of layers of A-type wave curved surfaces and a plurality of layers of B-type wave curved surfaces, a circulating multi-layer overlapping layer of a-B-B is formed by overlapping and assembling a plurality of layers of B-type wave curved surfaces, and the multi-layer overlapping layer of A-A-A, the circulating multi-layer overlapping layer of a-B-B and the multi-layer overlapping layer of B-B-B are overlapped and listed to form the packing for the liquid-liquid extraction tower. Preferably, when the interfacial tension gamma of the processed material is greater than or equal to an interfacial tension threshold, the angle of refraction of the A-type filler is 45-60 degrees, the angle of refraction of the B-type filler is 45-60 degrees, and when the interfacial tension gamma of the processed material is smaller than the interfacial tension threshold, the angle of refraction of the A-type filler is 15-45 degrees, the angle of refraction of the B-type filler is 15-45 degrees, and the interfacial tension threshold is 18-26 mN/m. Preferably, the packing for the liquid-liquid extraction tower is sequentially arranged into a multi-layer superposition layer of B-B-B, a multi-layer circulation multi-layer superposition layer of A-B-B and a multi-layer superposition layer of A-A-A from top to bottom, wherein the thickness ratio of each layer is the multi-layer superposition layer of B-B-B, namely the circulation multi-layer superposition layer of the multi-layer A-B, namely the multi-layer superposition layer of the multi-layer A-A-A is (0.8-1.1): (1.8-2.5): (7.5-8.5). Preferably, the packing for the liquid-liquid extraction tower