Bionic porous random packing and preparation and application thereof

Abstract

The invention discloses random packing of a bionic porous structure based on a triple-period minimal surface (TPMS) and a 3D printing preparation and application method of the random packing, and belongs to the technical field of packing. According to the method, a TPMS curved surface structure serves as a filler main body part and is combined with an annular shell with a flange. The polypropylene bionic porous random packing is prepared through the 3D printing technology, the nozzle temperature is 220 DEG C, the bottom plate temperature is 90 DEG C, the printing layer height is 0.2 mm, and the printing speed is 50 mm / s. According to the bionic porous random packing, the specific surface area of the packing can be effectively increased, the structural strength of the packing is improved, and the mass transfer effect of the packing is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fillers, in particular to a bionic porous random filler and a preparation and application method thereof. Background Art

[0002] Packing is widely used in chemical production and separation processes, mainly used to increase the gas-liquid contact area of ​​the gas-liquid fluid phase to improve the mass transfer efficiency. Packing can be divided into two categories according to the stacking method: random packing and structured packing. Compared with structured packing, random packing has the characteristics of easy installation and easy processing. The performance of random packing is closely related to its structure. Designing a new random packing structure with large specific surface area and low pressure drop is of great significance to improving the mass transfer performance of the packing tower. Traditional plastic packing is generally obtained by injection molding, and it is difficult to obtain a complex random packing structure. 3D printing technology (also known as additive manufacturing) can prepare more complex structures than traditional equal material manufacturing or subtractive manufacturing technology.

[0003] Triply Peoridic Minimal Surfaces are pore structures that change periodically in three-dimensional space, and the average curvature at any point on the surface is zero. Compared with traditional structures, they have the characteristics of large specific surface area, high specific strength, axisymmetric stiffness, and high connectivity. TPMS can accurately control the pore structure through implicit equations, and the implicit equation expression is:

[0004]

[0005] Among them A k is the amplitude factor; λ k is the period wavelength; r is the independent variable; P k is the phase offset. A series of common TPMS surfaces can be defined by implicit equations, such as Gyroid, Lidinoid, IWP, Diamond, Neovius, Primitive, etc. The following are their implicit equations.

[0006] Summary of the invention

[0007] The purpose of the present invention is to provide a novel bionic porous random packing design and preparation method, so as to increase the specific surface area of ​​the packing and improve the mass transfer efficiency of the packing.

[0008] To achieve the above objectives, the present invention proposes a novel TPMS bionic porous random packing, which has the advantages of large specific surface area, high porosity, good connectivity, etc.

[0009] Furthermore, the TPMS surface type is selected as Gyroid as the main internal structure of the filler.

[0010] Furthermore, the ratio of the diameter to the height of the annular shell is 2:1, which can shorten the gas path and reduce the gas flow resistance.

[0011] Furthermore, the outwardly expanded flange structure at the top of the packing structure shell can increase the specific surface area and optimize the fluid distribution.

[0012] Furthermore, windows are opened on the ring wall of the packing shell to increase the porosity of the packing and reduce the flow resistance of the fluid.

[0013] Furthermore, 3D printing technology was used to prepare a new type of TPMS bionic porous random packing.

[0014] After adopting the above structure, the present invention has the following advantages: the existence of the TPMS curved surface structure increases the specific surface area of ​​the random packing, provides a large contact area for the two phases of the fluid, is beneficial to increase the liquid holding capacity on the packing surface, and further improves the mass transfer efficiency; the average curvature of each point of the TPMS structure is zero, and it has a highly connected pore structure with a large porosity, which can reduce the mass transfer resistance; the TPMS minimum surface structure has the characteristics of low relative density and high specific strength, so that the prepared packing has greater rigidity and is not easy to deform or break. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A front view of an embodiment of a bionic porous random packing of the present invention

[0016] Figure 2 A top view of an embodiment of a bionic porous random packing of the present invention

[0017] Figure 3 The left side view of an embodiment of a bionic porous random packing of the present invention

[0018] Figure 4 A physical picture of an embodiment of a bionic porous random packing of the present invention

[0019] Figure 5 A comparison of the specific surface areas of a bionic porous random packing embodiment of the present invention and a common step ring

[0020] Figure 6 The CO of a bionic porous random packing embodiment of the present invention and a conventional step ring 2 Absorption efficiency comparison chart DETAILED DESCRIPTION

[0021] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0022] The TPMS surface generation software Flatt-Pack was used to generate the TPMS porous structure body with the TPMS surface type of Gyroid and export it in STL file format.

[0023] The three-dimensional drawing software 3ds Max 2022 is used to draw the filler shell. The shell structure is specifically a circular shell with the middle 1 / 3 of the ring hollowed out. The ratio of the filler diameter to the height is 2:1, and there is a trumpet-shaped flanging structure at 1 / 3 of the top height.

[0024] The STL file of the TPMS main structure was imported into the 3D drawing software 3ds Max 2022, and Boolean operations were performed on the highly consistent circular ring-shaped shell and the TPMS main structure to obtain a bionic porous structure random packing with an internal main body of the TPMS porous structure and an external circular ring shell with a flange. The packing diameter is 20 mm and the height is 10 mm.

[0025] See attached figure, Figure 1 , Figure 2 , Figure 3 They are respectively the front view, top view and side view of a bionic porous random packing according to an example of the present invention.

[0026] FDM 3D printing technology was used to prepare bionic porous random packing. Polypropylene was used as the raw material and TPMS bionic structure porous random packing was prepared by 3D printer. The 3D printing nozzle temperature was 220℃, the base plate temperature was 90℃, the printing layer height was 0.2mm, and the printing speed was 50mm / s.

[0027] Figure 4 This is a real picture of the TPMS porous random packing made of polypropylene according to an embodiment of the present invention.

[0028] The surface area and volume of TPMS porous random packing were measured using the 3D software 3ds Max 2022, and the specific surface area data of the packing was calculated and compared with the step rings of the same size and the same shell. Figure 5 shown.

[0029] The mass transfer performance of the TPMS porous random packing and the step ring packing made of polypropylene in the embodiment of the present invention was compared. The specific experimental conditions were that the TPMS packing and the step ring were filled into the carbon dioxide packing absorption tower, the packing layer height was 37 mm, and the rest of the packing tower was filled with metal wire mesh corrugated 250Y packing with a total height of 92.8 mm. A 30% mass fraction MEA solution was used as the absorbent to absorb CO 2 CO concentration of 14% 2 CO in the air mixture 2, the inlet air and liquid temperature is 40 degrees Celsius, the liquid flow rate is 15L / h, and the mixed gas flow rate is 6.3m 3 / h. TPMS porous random packing and step ring packing CO 2 Absorption efficiency comparison Figure 6 shown.

[0030] The present invention has developed a bionic porous random packing that applies the TPMS curved surface to the packing structure and uses 3D printing technology to prepare it. Compared with the step ring, the specific surface area of ​​the bionic porous random packing is increased by 22.60%. Under the same absorption experimental operating conditions, the mass transfer efficiency is significantly improved compared with the step ring, about 13.40%.

[0031] The above disclosure is only a specific embodiment of the present invention. Those skilled in the art may make various modifications and alterations based on this embodiment without departing from the spirit and scope of the present invention. However, the examples of the present invention are not limited thereto. Any changes that can be made by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A bionic porous random packing based on TPMS curved surface and its preparation and application, characterized in that: The steps include: (1) Select a TPMS surface type in the Flatt-Pack software, generate a TPMS bionic porous structure with a certain porosity, and create and export an STL file; (2) Importing the STL file described in step (1) into 3ds Max2022 software, combining it with the shell through Boolean operation, obtaining a complete TPMS bionic porous filler model, and exporting it as an STL model; (3) Using polypropylene as the raw material, TPMS bionic porous random packing was prepared by 3D printer printing. The printing parameters were as follows: nozzle temperature was 220°C, base plate temperature was 90°C, printing layer height was 0.2 mm, and printing speed was 50 mm / s.

2. A method for preparing a bionic porous random packing based on a TPMS curved surface according to claim 1, characterized in that: The TPMS structure is a curved surface structure such as Gyroid, Lidinoid, IWP, Diamond, Primitive, and Neovius.

3. A method for preparing a bionic porous random packing based on a TPMS curved surface according to claim 1, characterized in that: The filler is prepared by 3D printing technology, including fused deposition technology, stereolithography technology, laser sintering technology and other 3D printing technologies.

4. A method for preparing a bionic porous random packing based on a TPMS curved surface according to claim 1, characterized in that: The filler materials are polymers, metals and ceramics.

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