Graded-pore foamed ceramic filler, separation tower and preparation method of graded-pore foamed ceramic filler

Abstract

The invention relates to the technical field of chemical separation equipment, in particular to a graded pore foamed ceramic filler, a separation tower and a preparation method. The invention provides a separation tower, grade hole foam filler is used, the filler is prepared through a 3D printing process, the separation tower comprises a filler body, and the filler body is provided with fine holes and coarse holes; the aperture ratio of the thick holes to the thin holes is 2-5, and the volume ratio of the thin holes to the thick holes is 0.3-0.6. The invention aims to solve the technical problem that the flux and the mass transfer area cannot be balanced by a single aperture in the prior art.

Description

Technical Field

[0001] This invention relates to the technical field of chemical separation equipment, and in particular to a graded porous foam ceramic packing, a separation tower, and a preparation method thereof. Background Technology

[0002] Existing packing materials have limitations in chemical separation processes. For example, random packing materials suffer from severe channeling, while structured packing materials have excessively high pressure drops (ΔP > 8 kPa / m). In packing material design, throughput, mass transfer performance, and pressure drop are the three main considerations.

[0003] Chinese Utility Model Patent No. CN202410677U disclosed a foam ceramic structured corrugated packing on December 9, 2012. It consists of corrugated plates (2) stacked and interleaved to form a packing body (1). The corrugated plates (2) are made of foam ceramic material. The corrugated plates have a network of honeycomb holes (3) inside. The corrugated plates are provided with flow holes (4). Chinese Utility Model Patent No. CN211706792U disclosed a streamlined perforated plate corrugated packing on February 12, 2020. It includes a packing body, which includes ceramic corrugated plates (1). The ceramic corrugated plates are bonded and stacked to form a whole. There are cavities between the ceramic corrugated plates. The surfaces (6) of the ceramic corrugated plates are provided with parallel or interleaved flow holes (4). The total area of ​​the flow holes on each plate is 40-50% of the plate surface area. The axis of the flow holes is perpendicular to the surface of the corrugated plate. The flow holes are round holes. The aforementioned patent improves separation efficiency through honeycomb pores, but a single pore size cannot balance flux and mass transfer area.

[0004] Therefore, it is necessary to propose a graded pore foam ceramic packing, a separation tower, and a preparation method. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a graded pore foam ceramic packing, a separation tower and a preparation method, which aims to solve the technical problem that a single pore size cannot balance flux and mass transfer area in the prior art.

[0006] To achieve the above objectives, the present invention proposes a graded pore foam ceramic filler, comprising a filler body having fine pores and coarse pores; the pore diameter ratio of the coarse pores to the fine pores is 2-5, and the volume ratio of the fine pores to the coarse pores is 0.3-0.6.

[0007] Preferably, the filler body includes at least Al2O. 3、 SiO2 and MgO, wherein the coarse pores also include a hydrophobic agent.

[0008] Preferably, the Al2O3 is γ-Al2O3; the hydrophobic agent includes polydimethylsiloxane, carbon black, graphene, or phenolic resin; the weight parts of each component are: 85-90 parts of γ-Al2O3, 5-10 parts of SiO2, 2-5 parts of MgO, and 2-9 parts of hydrophobic agent.

[0009] Preferably, the diameter of the coarse pore is 1.5-3.0 mm; and the diameter of the fine pore is 0.3-0.8 mm.

[0010] Preferably, when the viscosity is 50-500 cP, the pore size ratio of the coarse pores to the fine pores is 2, and the volume ratio of the fine pores to the coarse pores is 0.5.

[0011] Preferably, the packing body is formed by connecting skeletons with triangular cross-sections, wherein the acute angle of the triangle is less than or equal to 60°; and the skeleton is formed by connecting tapered skeletons.

[0012] Preferably, the surface of the coarse pores is hydrophobically treated, with a contact angle greater than or equal to 110°; the surface of the fine pores is coated with a hydrophilic coating, with a contact angle less than or equal to 20°.

[0013] Preferably, the coarse pores include PTFE nanoparticles; the surface of the fine pores is provided with a hydrophilic coating with a contact angle of less than or equal to 20°, and the hydrophilic coating is a nitric acid coating.

[0014] Preferably, when the viscosity is 500-1500 cP, the pore size ratio of the coarse pores to the fine pores is 3.5, and the volume ratio of the fine pores to the coarse pores is 0.35.

[0015] To achieve the above objectives, the present invention proposes a separation tower that uses the aforementioned graded pore foam ceramic packing.

[0016] To achieve the above objectives, this invention proposes a method for preparing hierarchical porous foam ceramic packing, comprising the following steps: S1. Weigh the following proportions of γ-Al2O3: 85-90 parts, SiO2: 5-10 parts, MgO: 2-5 parts, and hydrophobic agent: 2-9 parts. 3、 Weigh out two portions of SiO2 and MgO, and prepare a solution using the hydrophobic agent; S2, grinding, removing one portion of γ-Al2O from S1 3、 SiO2 and MgO particles were added to the hydrophobic agent solution and ball-milled to mix the components evenly into a hydrophobic material; another portion of γ-Al2O2 was separately added. 3、 SiO2 and MgO particles are ball-milled and mixed to obtain a common material; S3, 3D printing, uses extruders to press ordinary materials and hydrophobic materials separately before they are fed into the 3D printing unit for printing. During the printing process, hydrophobic materials are used to print large holes, while ordinary materials are used to print other parts. S4, pyrolysis: Under an inert atmosphere, slowly heat to 500-600°C at a rate of less than 3°C / min and hold for 1-2 hours; then switch to an air atmosphere and heat to 1000-1500°C at a rate of 9-14°C / min and hold for 0.5-1 hour. S5, hydrophobic treatment, involves immersing the material obtained in S4 in a fluid containing PTFE nanoparticles. S6, hydrophilic treatment, involves immersing the material obtained in S5 in a nitric acid solution to finally obtain the desired filler.

[0017] Compared with the prior art, the beneficial effects of the graded pore foam ceramic packing and separation tower provided by the present invention are as follows: By synergistically enhancing the flow and absorption processes through altering the pore size ratio and pore volume of fine and coarse pores, the theoretical plate number can be maximized. The flux and mass transfer area are balanced through the pore size ratio, the theoretical plate number is maximized through the fine pore volume fraction, and the boundary layer is disrupted through the skeleton interface shape to reduce pressure drop.

[0018] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the packing material according to an embodiment of the present invention.

[0020] Figure 2 This is a model diagram of the packing material according to an embodiment of the present invention.

[0021] In the diagram: 1. Coarse pore; 2. Fine pore. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0023] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0024] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] A ceramic foam filler containing at least Al2O 3、 SiO2 and MgO, with hydrophobic and hydrophilic agents added. A separation tower suitable for efficient separation in chemical processes such as fluoride ion removal from flue gas, ethanol dehydration, and crude oil fractionation; it can be a distillation tower, absorption tower, etc. (See also...) Figure 1 and Figure 2 This invention provides a separation tower in which PTFE-based hierarchical porous foam ceramic packing is installed. The multi-level pore structure synergistically enhances gas-liquid mass transfer and throughput, making it suitable for efficient separation processes such as fluoride ion removal, ethanol dehydration, and crude oil fractionation. Ideally, packing should possess high throughput, low pressure drop, high mass transfer efficiency, and high absorption performance; however, only one optimal state can be achieved in reality. The packing of this invention features a hierarchical pore structure. The fine pores (2) have a large specific surface area, improving absorption efficiency, while the large pore size (1) ensures high mass transfer performance and high throughput.

[0027] The foam filler comprises: the filler body includes at least Al2O3. 3、The mixture comprises SiO2 and MgO, wherein the coarse pores 1 further include a hydrophobic agent, and the Al2O3 is γ-Al2O3; the hydrophobic agent includes polydimethylsiloxane, carbon black, graphene, or phenolic resin; the weight parts of each component are: γ-Al2O3 85-90 parts, SiO2 5-10 parts, MgO 2-5 parts, and hydrophobic agent 2-9 parts. After mixing the above components together, the desired foam filler is 3D printed. γ-Al2O3 (activated alumina) has a high specific surface area and abundant pore structure, providing excellent adsorption performance and catalytic active sites, which can increase the specific surface area of ​​the filler and enhance mass transfer efficiency. SiO2 (silicon dioxide) has stable chemical properties, good acid resistance, and a low coefficient of thermal expansion, which can improve the overall strength and thermal stability of the material, and as a structural framework, improve the mechanical strength and durability of the filler. MgO (magnesium oxide) can adjust the coefficient of thermal expansion of materials, improve their stability in alkaline environments, and form composite ceramic phases with Al2O3 and SiO2, thereby improving overall performance.

[0028] The coarse pores 1 have a diameter of 1.5-3.0 mm (d=1.5-3.0 mm), creating a high-speed gas-phase channel and increasing the flooding gas velocity to 4.2 m / s. A hydrophobic surface treatment (contact angle greater than or equal to 110°) reduces liquid film coverage. Furthermore, a PTFE nanoparticle coating can be applied to the coarse pores 1 to enhance hydrophobicity.

[0029] The pore diameter of the fine pore 2 is 0.3-0.8 mm (d=0.3-0.8 mm). The surface of the fine pore 2 can be modified with nitric acid to promote hydrophilicity (contact angle ≤20°) to promote liquid film spreading.

[0030] The pressure drop model of the packing body is as follows: μ: fluid viscosity, unit: cP; The separation efficiency of the packing body is .

[0031] Furthermore, the pore size ratio of the coarse pore 1 to the fine pore 2 is selected to be 2-5, and the volume ratio of the fine pore 2 to the coarse pore 1 is 0.3-0.6. By balancing the mass transfer and absorption processes through the pore size ratio (dcoarse / dfine) and the fine pore volume fraction (Vfine / Vtotal), the maximum theoretical plate number is obtained.

[0032] In an optional embodiment, when the viscosity is 50-500 cP, in the case of viscous systems such as fluoride ion removal and ethanol dehydration, the pore size ratio of coarse pores 1 to fine pores 2 is 2, and the volume ratio of fine pores 2 to coarse pores 1 [fine pore volume fraction (Vfine / Vtotal)] is 0.5. Specifically, in the ethanol-water system (reflux ratio 3:1): height of equal plate (HETP): 0.12 m (a 52% reduction compared to the traditional packing of 0.25 m); pressure drop: 4.3 kPa / m (a 51% reduction compared to the structured packing of 8.7 kPa / m).

[0033] In an optional embodiment, when the viscosity is 500-1500 cP, during crude oil fractionation, the parameters are adjusted so that the pore size ratio of coarse pores 1 to fine pores 2 is 3.5, and the volume ratio of fine pores 2 to coarse pores 1 [pore volume fraction (Vfine / Vtotal)] is 0.35. The pore size ratio increases relative to lower viscosity, expanding the flow channels. The pore volume fraction (Vfine / Vtotal) decreases relative to lower viscosity, reducing resistance.

[0034] High separation performance is achieved by using the packing material of this invention. The integrally packed packing is fixed inside the tower and is mainly used in absorption separation towers to separate two different media using an absorbent. The packing enhances the absorption effect, such as using water to absorb fluoride from flue gas. The packing material exhibits low pressure drop and excellent mass transfer performance. It achieves increased throughput: the flooding gas velocity reaches 4.2 m / s, increasing the throughput by 68%. It features an anti-clogging design: the flow velocity in the coarse-pore zone is >0.5 m / s, preventing particle deposition. Furthermore, its viscosity compatibility range is 50-1500 cP, broadening its applicability.

[0035] Example 1: This invention also provides a method for preparing graded porous foam ceramic filler, used to prepare the above-mentioned graded porous foam ceramic filler, S1, weighing, according to the proportions of 85 parts γ-Al2O3, 5 parts SiO2, 2 parts MgO, and 2 parts hydrophobic agent, weighing the corresponding particles, wherein γ-Al2O3... 3、 Two portions of SiO2 and MgO were weighed out (i.e., 85 parts of γ-Al2O3, 5 parts of SiO2, and 2 parts of MgO, with two portions of each), and a hydrophobic agent was prepared into a solution; the hydrophobic agent chosen was polydimethylsiloxane, a component that does not easily lose its hydrophobic properties during subsequent nitric acid soaking. Because γ-Al2O3... 3、 The organism composed of SiO2 and MgO has a certain ability to adsorb nitric acid, so there is no need to mix hydrophilic materials into the organism; S2, grinding, removing one portion of γ-Al2O from S1 3、 SiO2 and MgO particles (85 parts γ-Al2O3, 5 parts SiO2, and 2 parts MgO) were added to the hydrophobic agent solution and ball-milled to mix the components evenly into a hydrophobic material; another part of γ-Al2O3 was separately added to the solution.3、 SiO2 and MgO particles (85 parts γ-Al2O3, 5 parts SiO2, and 2 parts MgO) were ball-milled to obtain a common material; S3, 3D printing: Ordinary material and hydrophobic material are extruded separately through an extruder and then fed into a 3D printing unit for printing (dispersants, thickeners, etc. are required during the extrusion process, and these can be materials from the prior art, which do not have a substantial impact on the solution of this invention). During the printing process, hydrophobic material is used to print the coarse holes 1, and ordinary material is used to print the other parts; preferably, the program is set to set grooves on the coarse holes during 3D printing, thereby increasing the adsorption performance (the same solution is used in Examples 2 and 3). S4, Pyrolysis: Under an inert atmosphere (nitrogen or argon, etc.), slowly raise the temperature to 500-600°C at a rate of less than 3°C / min (preferably 2°C / min) and hold for 1-2 hours. This process allows the polydimethylsiloxane to fully crosslink and transform into amorphous carbon, preventing oxidation. The temperature should not rise too quickly to avoid affecting the hydrophobic properties of the polydimethylsiloxane. Then switch to an air atmosphere and raise the temperature to 1000-1500°C at a rate of 9-14°C / min, holding for 0.5-1 hour. The holding time should not be too long to avoid affecting the hydrophobic properties. S5, hydrophobic treatment: The material obtained in S4 is immersed in a fluid containing PTFE nanoparticles. Grooves are coarsely designed to facilitate adsorption in the grooves through the fluid. The addition of grooves also improves the adsorption effect (the same solution is used in Examples 2 and 3). S6, hydrophilic treatment, the material obtained in S5 is soaked in nitric acid solution to finally obtain the desired filler. The selected nitric acid solution is dilute nitric acid, which is less likely to affect the hydrophobic properties of the hydrophobic agent (the same scheme is used in Examples 2 and 3).

[0036] Example 2: For the preparation of the above-mentioned graded porous foam ceramic filler, S1, weighing, according to the proportions of 90 parts γ-Al2O3, 10 parts SiO2, 5 parts MgO, and 9 parts hydrophobic agent, weigh the corresponding particles, wherein γ-Al2O3... 3、 Weigh out two portions of SiO2 and MgO, and prepare a solution using the hydrophobic agent; S2, grinding, removing one portion of γ-Al2O from S1 3、 SiO2 and MgO particles were added to the hydrophobic agent solution and ball-milled to mix the components evenly into a hydrophobic material; another portion of γ-Al2O2 was separately added. 3、 SiO2 and MgO particles are ball-milled and mixed to obtain a common material; S3, 3D printing: Ordinary material and hydrophobic material are extruded separately through an extruder and then fed into a 3D printing unit for printing (dispersants, thickeners, etc. are required during the extrusion process, and these can be selected from existing materials, which do not have a substantial impact on the solution of this invention). During the printing process, hydrophobic material is used to print the coarse holes 1, while ordinary material is used to print other parts; preferably, the program is set to set grooves on the coarse holes during 3D printing to increase the adsorption performance; S4, pyrolysis: Under an inert atmosphere, slowly raise the temperature to 500-600°C at a rate of less than 3°C / min (preferably 2 minutes) and hold for 1-2 hours; then switch to an air atmosphere and raise the temperature to 1000-1500°C at a rate of 9-14°C / min and hold for 0.5-1 hour. S5, hydrophobic treatment, involves immersing the material obtained in S4 in a fluid containing PTFE nanoparticles. S6, hydrophilic treatment, involves immersing the material obtained in S5 in a nitric acid solution to finally obtain the desired filler.

[0037] Example 3: For the preparation of the above-mentioned graded porous foam ceramic filler, S1, weighing, according to the proportions of γ-Al2O3 87 parts, SiO2 8 parts, MgO 4 parts, and hydrophobic agent 5 parts, weigh the corresponding particles, wherein γ-Al2O3 3、 Weigh out two portions of SiO2 and MgO, and prepare a solution using the hydrophobic agent; S2, grinding, removing one portion of γ-Al2O from S1 3、 SiO2 and MgO particles were added to the hydrophobic agent solution and ball-milled to mix the components evenly into a hydrophobic material; another portion of γ-Al2O2 was separately added. 3、 SiO2 and MgO particles are ball-milled and mixed to obtain a common material; S3, 3D printing: Ordinary material and hydrophobic material are extruded separately through an extruder and then fed into a 3D printing unit for printing (dispersants, thickeners, etc. are required during the extrusion process, and these can be selected from existing materials, which do not have a substantial impact on the solution of this invention). During the printing process, hydrophobic material is used to print the coarse holes 1, while ordinary material is used to print other parts; preferably, the program is set to set grooves on the coarse holes during 3D printing to increase the adsorption performance; S4, pyrolysis: Under an inert atmosphere, slowly raise the temperature to 500-600°C at a rate of less than 3°C / min (preferably 2 minutes) and hold for 1-2 hours; then switch to an air atmosphere and raise the temperature to 1000-1500°C at a rate of 9-14°C / min and hold for 0.5-1 hour. S5, hydrophobic treatment, involves immersing the material obtained in S4 in a fluid containing PTFE nanoparticles. S6, hydrophilic treatment, involves immersing the material obtained in S5 in a nitric acid solution to finally obtain the desired filler.

[0038] After measuring the theoretical plate number, pressure drop, separation efficiency, and other data of the packing in Test Examples 1-3, and comparing them with ceramic Raschig ring random packing, it was found that the theoretical plate number, pressure drop, and separation efficiency were all better.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A graded porous foam ceramic packing, comprising a packing body, characterized in that: The packing body is provided with fine pores (2) and coarse pores (1); the pore diameter ratio of the coarse pores (1) to the fine pores (2) is 2-5, and the volume ratio of the fine pores (2) to the coarse pores (1) is 0.3-0.

6.

2. The graded porous foam ceramic packing as described in claim 1, characterized in that: The filler body includes at least Al2O 3、 SiO2 and MgO, wherein the coarse pores (1) also include a hydrophobic agent.

3. The graded porous foam ceramic packing as described in claim 2, characterized in that: The Al2O3 is γ-Al2O3; the hydrophobic agent includes polydimethylsiloxane, carbon black, graphene, or phenolic resin; the weight parts of each component are: γ-Al2O3 85-90 parts, SiO2 5-10 parts, MgO 2-5 parts, and hydrophobic agent 2-9 parts.

4. The graded porous foam ceramic packing as described in claim 1, characterized in that: The diameter of the coarse hole (1) is 1.5-3.0 mm; the diameter of the fine hole (2) is 0.3-0.8 mm.

5. The graded porous foam ceramic packing as described in claim 1, characterized in that: When the viscosity is 50-500 cP, the pore size ratio of the coarse pore (1) to the fine pore (2) is 2, and the volume ratio of the fine pore (2) to the coarse pore (1) is 0.

5.

6. The graded porous foam ceramic packing as described in claim 1, characterized in that: The packing body is formed by connecting a skeleton with a triangular cross-section, wherein the acute angle of the triangle is less than or equal to 60°; the skeleton is formed by connecting conical skeletons.

7. The graded porous foam ceramic packing as described in claim 4, characterized in that: The surface of the coarse pores (1) is hydrophobically treated, with a contact angle greater than or equal to 110°, and the hydrophobic material is PTFE nanoparticles; The surface of the fine pore (2) is provided with a hydrophilic coating with a contact angle of less than or equal to 20°, and the hydrophilic coating is a nitric acid coating.

8. The graded porous foam ceramic packing as described in claim 1, characterized in that: When the viscosity is 500-1500 cP, the pore size ratio of the coarse pore (1) to the fine pore (2) is 3.5, and the volume ratio of the fine pore (2) to the coarse pore (1) is 0.

35.

9. A separation tower, characterized in that: The graded pore foam ceramic packing as described in any one of claims 1-8 was used.

10. A method for preparing graded porous foam ceramic filler, characterized in that: The method for preparing graded porous foam ceramic packings according to any one of 1-8 comprises the following steps: S1. Weigh the corresponding particles according to the following proportions: 85-90 parts γ-Al2O3, 5-10 parts SiO2, 2-5 parts MgO, and 2-9 parts hydrophobic agent. 3、 Weigh out two portions of SiO2 and MgO, and prepare a solution using the hydrophobic agent; S2, grinding, removing one portion of γ-Al2O from S1 3、 SiO2 and MgO particles were added to the hydrophobic agent solution and ball-milled to mix the components evenly into a hydrophobic material; another portion of γ-Al2O2 was separately added. 3、 SiO2 and MgO particles are ball-milled and mixed to obtain a common material; S3, 3D printing, ordinary material and hydrophobic material are extruded by an extruder and then fed into the 3D printing assembly for printing. During the printing process, hydrophobic material is used to print the coarse holes (1), and ordinary material is used to print the other parts. S4, pyrolysis: Under an inert atmosphere, slowly heat to 500-600°C at a rate of less than 3°C / min and hold for 1-2 hours; then switch to an air atmosphere and heat to 1000-1500°C at a rate of 9-14°C / min and hold for 0.5-1 hour. S5, hydrophobic treatment, involves immersing the material obtained in S4 in a fluid containing PTFE nanoparticles. S6, hydrophilic treatment, involves immersing the material obtained in S5 in a nitric acid solution to finally obtain the desired filler.

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