A configuration of a dish-shaped ceramic membrane and its preparation method.

Abstract

This invention discloses a configuration of a disc-shaped ceramic membrane and a method for preparing the ceramic membrane. The support body is formed by joining two structurally identical support body units with their inner surfaces joined together. On the inner surface of the support body unit, there is an outer circular convex ring at the outer edge and an inner circular hole with a concentric circular structure in the center. Spokes are evenly distributed and spaced between the outer circular convex ring and the inner circular hole. Connectors and slots are evenly distributed on the outer circular convex ring. The connectors are protrusions and grooves, which are corresponding and adapted in shape and are arranged alternately in position. The slots are located in the middle between adjacent connectors. The two support body units are joined together with their inner surfaces to form the support body. The protrusion of one unit is fitted into the groove of the other unit, and the slots are joined together. After the slots are joined, ceramic wedges are provided inside as connections. The present invention uses connectors and slots on the outer convex ring, combined with ceramic wedges, to strengthen the connection between the two support units. The resulting support is firmly connected, and the spokes support the disc ceramic membrane in a mirror cross pattern. This significantly improves the mechanical strength and product qualification rate of the product, while also effectively increasing the effective filtration area and permeation flux of the disc ceramic membrane.

Description

Technical Field

[0001] This invention relates to the field of ceramic membrane separation technology, and in particular to a configuration of a disc-type ceramic membrane and a method for preparing the ceramic membrane. Background Technology

[0002] Disc-type ceramic membranes are ceramic membranes shaped like flying saucers, with the separation layer on the outer surface and the permeation channels inside the cavity. Unlike flat-sheet and tubular ceramic membranes, the separation process of disc-type ceramic membranes is mainly achieved through membrane rotation, rather than feed flow or disturbance. During membrane rotation, a shear force is generated at the interface between the membrane and the feed. This shear force can effectively remove the fouling layer on the outer surface of the membrane, mitigate membrane surface fouling, increase membrane operating time, extend membrane life, and reduce membrane operating costs. It is particularly suitable for feed systems with high concentration / high viscosity separation requirements, such as those used in bio-fermentation, craft beer brewing, powder preparation, and landfill leachate treatment.

[0003] There are various methods for preparing disc-shaped ceramic membranes, including dry pressing, plastic molding, slip casting, and 3D printing. Their internal cavity structures are mainly hollow or distributed water collection channels. However, hollow-cavity disc-shaped ceramic membranes suffer from low strength and easy deformation. To address this, existing technologies use radially symmetrical external support spokes arranged on the outer surface of the disc. However, these spokes affect the disturbance of the feed liquid during membrane rotation, thus affecting the shear force and fouling of the membrane surface, reducing the separation efficiency of the disc-shaped ceramic membrane. Distributed water collection channels are generally hollow structures or parabolic, linear, zigzag, speckled, or honeycomb structures. Existing technologies employ the following preparation process: first, the ceramic membrane support material is laid on a mold to form the first support layer; then, a loose, combustible material such as carbon powder or starch is laid on the surface of the first support layer; finally, the ceramic membrane support material is laid on the first support layer and the loose material surface and dry-pressed into a single unit. During calcination, the porous material is fully carbonized and forms a water-collecting channel structure within the cavity. By sacrificing the porous layer during combustion to create these channels, an integrated molding technology for dish-shaped ceramic membranes is achieved, thereby improving production efficiency. However, the fluidity and uniformity of the porous layer during the pressing process directly affect the deformation and cracking of the surface and interior of the dish-shaped ceramic membrane, leading to a decrease in the yield. Furthermore, existing technologies also include slip casting and dry pressing to prepare dish-shaped ceramic membranes with parabolic water-collecting channels within the cavity.

[0004] Among existing disc-type ceramic membrane manufacturing processes, the dry pressing method boasts a high yield and production efficiency. Within the internal cavity structure of existing disc-type ceramic membranes, hollow cavities offer high permeation flux but have a low yield. Structures with distributed water collection channels have a higher yield; however, the symmetrically distributed, parabolic or linear water collection channels occupy the effective feed permeation area, reducing membrane permeation efficiency. Furthermore, the bonding operation between the upper and lower water collection channels of the disc-type ceramic membrane is complex and prone to defects that reduce strength. Therefore, improving the structural shortcomings of existing disc-type ceramic membranes is crucial for enhancing their permeation efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a disc-shaped ceramic membrane configuration. This configuration consists of two identical support units joined together on their inner surfaces to form the support body. Connectors and slots on the outer convex ring, combined with ceramic wedges, strengthen the connection between the two support units. Spokes provide mirror-image cross-support for the disc-shaped ceramic membrane, thereby improving the stability of the support body connection, significantly increasing the product's mechanical strength and yield, and effectively enhancing the effective filtration area and permeate flux of the disc-shaped ceramic membrane. Another objective of this invention is to provide a method for preparing the aforementioned disc-shaped ceramic membrane.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides a configuration for a disc-shaped ceramic membrane. The support body of the disc-shaped ceramic membrane is composed of two structurally identical support units joined together at their inner surfaces. On the inner surface of each support unit, there is an outer circular convex ring at the outer edge and an inner circular hole with a concentric circular structure in the center. Spokes are evenly distributed and spaced between the outer circular convex ring and the inner circular hole, arranged radially, and the height of the spokes and the outer circular convex ring are the same. Connectors and slots are evenly distributed on the outer circular convex ring. The connectors are protrusions and grooves, which are corresponding and adapted in shape and alternately spaced in position. The slots are located in the middle between adjacent connectors.

[0008] The two support units are joined together on their inner surfaces to form a support. The protrusion of one unit is fitted into the groove of the other unit, and the slots are connected to each other. After the slots are connected, ceramic wedges are provided inside as a connection.

[0009] Furthermore, the protrusion of the present invention is trapezoidal, and the groove is an inverted trapezoidal. The spokes are parabolic, with long and short strips alternating at intervals, and their outer ends are all connected to the outer convex ring. The inner ends of the long strips are located at the edge of the inner hole, and the interval between the inner ends of adjacent long strips forms a disc-shaped ceramic membrane permeate outlet.

[0010] In the above scheme, the outer diameter of the support body unit of the present invention is 20-40cm, the diameter of the inner circular hole is 5-10cm, and there are 4-12 spokes; the height of the outer circular convex ring and the spokes is 0.2-0.4cm, and their widths are the same and are 0.4-0.8cm; the diameter of the slot is 0.2-0.4cm, and the depth is 0.2-0.4cm; the width of the protrusion / groove is the same as the width of the outer circular convex ring, the height / depth is less than or equal to the height of the outer circular convex ring, and the length of the longest side is 0.4-0.8cm.

[0011] Another objective of this invention is achieved through the following technical solution:

[0012] The method for preparing the above-mentioned dish-type ceramic membrane provided by the present invention includes the following steps:

[0013] (1) Preparation of support monomer

[0014] Ceramic powder raw materials, binder and water are ball-milled and mixed, and then spray-granulated to obtain near-spherical particle agglomerates A with a particle size of 0.2 to 0.5 mm; then, after being pressed into shape by molding, the support monomer is obtained by drying and calcination (1);

[0015] (2) Preparation of cylindrical ceramic wedges

[0016] Ceramic powder raw materials, binder, and water are ball-milled and mixed, and then spray-granulated to obtain near-spherical particle agglomerates B with a particle size of 0.2-0.5 mm; then, they are pressed into shape by molding, and after demolding, cylindrical ceramic wedges are obtained.

[0017] (3) Preparation of dish-type ceramic membrane components

[0018] A separation membrane layer was prepared on the outer surface of the support monomer by dip coating. After drying at a temperature of 80-110°C, a dish-shaped ceramic membrane component with a green layer of separation membrane layer was obtained.

[0019] (4) Preparation of dish ceramic membrane

[0020] Take one disc-shaped ceramic membrane component, place one end of the ceramic wedge into the slot, and apply adhesive slurry to the surface of the outer convex ring and spokes; take another disc-shaped ceramic membrane component, and align the inner surfaces of the two disc-shaped ceramic membrane components together, with the protrusion of one component corresponding to the groove of the other component, and the gap between the inner ends of the long spokes forming the permeate outlet of the disc-shaped ceramic membrane; align the slot of the other disc-shaped ceramic membrane component with the other end of the ceramic wedge to achieve bonding and fixation between the two disc-shaped ceramic membrane components, and obtain a disc-shaped ceramic membrane with a separation membrane layer after drying and calcination.

[0021] Further, in step (1) of the preparation method of the present invention, the ceramic powder raw material is one or a combination of alumina, zirconium oxide, titanium oxide, and silicon carbide; the binder is one or a combination of CMC, HPMC, and lignin, with a mass ratio of ceramic powder raw material: binder: water = 100:0.2-1:50-70; the molding pressure of the compression molding method is 30-50 MPa, and the holding time is 30-60 s; the calcination temperature is 1380-1680℃, and the holding time is 1-3 h. The average pore size of the support is 0.5-5 μm, the porosity is >35%, and the flexural strength is >80 MPa.

[0022] Furthermore, in step (2) of the preparation method of the present invention, the ceramic powder raw material is one or a combination of kaolin, magnesium oxide, quartz, cordierite, mullite, spodumene, and titanium dioxide, and the binder is one or a combination of CMC, HPMC, and lignin, with a mass ratio of ceramic powder raw material: binder: water = 100:0.1~0.5:50~70; the molding pressure of the compression molding method is 10~20MPa, and the holding time is 30~60s.

[0023] In the above scheme, the calcination temperature in step (4) of the preparation method of the present invention is 1150~1350℃, the holding time is 1~3h, the thickness of the separation membrane is 10~50μm, and the average pore size is 0.05~0.2μm.

[0024] The present invention has the following beneficial effects:

[0025] (1) The connector on the outer convex ring of this invention strengthens the connection between the two support units, which is beneficial to improving the bonding stability of the support. At the same time, a slot is provided on the outer convex ring, and the two units of the support are connected by ceramic wedges. At the calcination temperature, the ceramic wedges shrink, melt and fill the slot, which improves the working efficiency and product qualification rate of bonding between the dish support units, and also greatly improves the bonding strength of the dish ceramic film.

[0026] (2) The present invention adopts an in-cavity cross spoke support disc ceramic membrane, which significantly improves the mechanical strength and the product qualification rate compared with the cavity disc ceramic membrane. Compared with the symmetrical bonding disc ceramic membrane, the clamp-shaped support spokes of the present invention only form a permeation blind spot at the intersection, while the liquid can still be permeated and separated at the other spokes, which improves the effective filtration area and permeation flux of the disc ceramic membrane.

[0027] (3) In this invention, when the coefficient of thermal expansion of the ceramic wedge is lower than that of the dish-type ceramic membrane monomer, the volume shrinkage at the calcination temperature is 5-30%, and the difference between the coefficient of thermal expansion of the ceramic wedge and that of the dish-type ceramic membrane monomer is >3.0*10. -6 / ℃. During the cooling process, because the thermal expansion coefficient of the disc ceramic membrane monomer is greater than that of the ceramic wedge, compressive stress is applied to the ceramic wedge in all directions, which further enhances the bonding tightness between the disc ceramic membrane monomers and the overall strength. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings:

[0029] Figure 1 This is one of the structural schematic diagrams of the support unit in the embodiments of the present invention;

[0030] Figure 2 This is a second structural schematic diagram of the support unit in an embodiment of the present invention (a: front view; b: rear view);

[0031] Figure 3 This is a schematic diagram of the structure of the disc-type ceramic membrane according to an embodiment of the present invention.

[0032] In the diagram: Support unit 1, outer convex ring 2, protrusion 2a, groove 2b, slot 2c, inner hole 3, spoke 4, outer end of spoke 4a, inner end of spoke 4b Detailed Implementation

[0033] Figures 1-3 The illustration shows an embodiment of the configuration of a dish-shaped ceramic membrane and its preparation method according to the present invention. In this embodiment, the configuration of the dish-shaped ceramic membrane is such that its support is formed by joining the inner surfaces of two structurally identical support monomers 1.

[0034] like Figure 1 and Figure 2 As shown, on the inner surface of the support unit 1 (outer diameter 35cm) (the thickness between the bottom of the inner surface and the outer surface is 0.3cm), there is an outer circular protrusion 2 at the outer edge, and an inner circular hole 3 with a diameter of 8cm in a concentric circular structure in the center. Connectors and slots 2c are evenly distributed on the outer circular protrusion 2. The connectors are trapezoidal protrusions 2a and inverted trapezoidal grooves 2b. The two are corresponding and adapted in shape and are arranged alternately in position. The slots 2c are located in the middle between adjacent connectors.

[0035] Twelve parabolic spokes 4 are evenly distributed between the outer convex ring 2 and the inner circular hole 3, arranged radially with alternating long and short spokes. The outer ends 4a of the spokes 4 are connected to the outer convex ring 2, and the inner ends 4b of the long spokes 4 are located at the edge of the inner circular hole 3. The intervals between the inner ends 4b of adjacent long spokes 4 form the permeate outlet of the disc-shaped ceramic membrane.

[0036] The outer convex ring 2 and the spokes 4 are both 0.3cm high and 0.6cm wide. The groove 4c has a diameter of 0.3cm and a depth of 0.3cm. The width of the protrusion 2a / groove 2b is the same as the width of the outer convex ring 2, and the height / depth is 0.2cm, with the longest side being 0.4cm long.

[0037] The support body is formed by the inner surfaces of two support body units 1 joined together. The protrusion 2a of one unit corresponds to the groove 2b of the other unit, and the slots 2c are connected to each other. After the slots 2c are connected, a ceramic wedge is provided inside for connection. The spokes 4 are mirror-reversed and crossed (see...). Figure 3 ).

[0038] The preparation method of the above-mentioned dish-type ceramic membrane comprises the following steps:

[0039] (1) Preparation of support monomer 1

[0040] 90 parts by weight of alumina powder, 10 parts by weight of titanium dioxide powder, 2 parts by weight of HPMC and 100 parts by weight of water were ball-milled and mixed to obtain near-spherical particle agglomerates A with a particle size of 0.35 mm by spray granulation. Then, the agglomerates were formed by compression molding at a pressure of 35 MPa for 40 s. After demolding, they were calcined at 1620 °C for 2 h to obtain support monomer 1.

[0041] (2) Preparation of cylindrical ceramic wedges

[0042] 95 parts by weight of cordierite, 5 parts by weight of quartz, 4 parts by weight of CMC and 80 parts by weight of ball milling are mixed and spray granulation is performed to obtain near-spherical particle agglomerates B with a particle size of 0.25 mm. Then, the mixture is molded under a pressure of 10 MPa for 30 s and demolded to obtain cylindrical ceramic wedges with a diameter of 0.3 cm and a height of 0.55 cm.

[0043] (3) Preparation of dish-type ceramic membrane components

[0044] A separation membrane layer was prepared on the outer surface of the above-mentioned support monomer 1 by dip coating. After drying at 100°C, a dish-shaped ceramic membrane component with a separation membrane green layer was obtained.

[0045] (4) Preparation of dish ceramic membrane

[0046] Take a disc-shaped ceramic membrane component, place one end of the ceramic wedge into the slot 2c, and apply adhesive slurry to the surface of the outer convex ring 2 and the spokes 4; take another disc-shaped ceramic membrane component, and align the inner surfaces of the two disc-shaped ceramic membrane components together, with the protrusion 2a of one component correspondingly fitting into the groove 2b of the other component, and the spokes 4 crossing in a mirror-like flipped manner, with the interval between the inner ends 4b of two adjacent long strip spokes 4 forming the permeate outlet of the disc-shaped ceramic membrane; align the slot 2c of the other disc-shaped ceramic membrane component with the other end of the ceramic wedge to achieve the bonding and fixation between the two disc-shaped ceramic membrane components, and obtain a disc-shaped ceramic membrane support green body, which is dried, calcined at 1300℃, and held for 2 hours to obtain a disc-shaped ceramic membrane with a separation membrane layer (separation membrane layer thickness of 28μm and average pore size of 0.1μm).

[0047] The disc-shaped ceramic membrane support of this invention has an average pore size of 3.8 μm, a porosity of 36.5%, a flexural strength of 96 MPa, and a coefficient of thermal expansion of 7.45 × 10⁻⁶ at 25–1000 °C. -6 / ℃; the volume shrinkage of the cylindrical ceramic wedge after calcination is 8.6%, and the coefficient of thermal expansion between 25 and 1000℃ is 4.12*10. -6 / ℃.

Claims

1. A configuration of a disc-shaped ceramic membrane, characterized in that: The support body of the disc-shaped ceramic membrane is composed of two identical support body units (1) joined together on their inner surfaces. On the inner surface of the support body unit (1), there is an outer circular convex ring (2) at the outer edge and an inner circular hole (3) with a concentric circular structure in the center. Spokes (4) are evenly distributed and spaced between the outer circular convex ring (2) and the inner circular hole (3). The spokes (4) are arranged in a radial pattern and the height of the spokes (4) and the outer circular convex ring (2) is the same. Connectors and slots (2c) are evenly distributed on the outer circular convex ring (2). The connectors are protrusions (2a) and grooves (2b), which are corresponding and adapted in shape and are arranged alternately in position. The slots (2c) are located in the middle between adjacent connectors. The two identical support units (1) are joined together on their inner surfaces to form a support. The protrusion (2a) of one unit is fitted into the groove (2b) of the other unit, and the slots (2c) are joined together. After the slots (2c) are joined, ceramic wedges are provided inside as a connection.

2. The configuration of the disc-shaped ceramic membrane according to claim 1, characterized in that: The protrusion (2a) is trapezoidal, and the groove (2b) is an inverted trapezoidal.

3. The configuration of the disc-shaped ceramic membrane according to claim 1 or 2, characterized in that: The spokes (4) are parabolic in shape and are arranged in alternating long and short strips. Their outer ends (4a) are all connected to the outer convex ring (2). The inner ends (4b) of the long spokes (4) are located at the edge of the inner hole (3). The interval between the inner ends (4b) of adjacent long spokes (4) forms the permeate outlet of the disc ceramic membrane.

4. The method for preparing the dish-shaped ceramic membrane according to any one of claims 1-3, characterized in that... Includes the following steps: (1) Preparation of support monomer (1) Ceramic powder raw materials, binder and water are ball-milled and mixed, and then spray-granulated to obtain near-spherical particle agglomerates A with a particle size of 0.2 to 0.5 mm; then, after being pressed into shape by molding, the support monomer is obtained by drying and calcination (1); (2) Preparation of cylindrical ceramic wedges Ceramic powder raw materials, binder, and water are ball-milled and mixed, and then spray-granulated to obtain near-spherical particle agglomerates B with a particle size of 0.2-0.5 mm; then, they are pressed into shape by molding, and after demolding, cylindrical ceramic wedges are obtained. (3) Preparation of dish-type ceramic membrane components A separation membrane layer was prepared on the outer surface of the support monomer (1) by dip coating. After drying at a temperature of 80-110°C, a dish-shaped ceramic membrane component with a separation membrane green layer was obtained. (4) Preparation of dish-type ceramic membranes Take a disc-shaped ceramic membrane component, place one end of the ceramic wedge into the slot (2c), and apply adhesive slurry to the surface of the outer convex ring (2) and spokes (4); take another disc-shaped ceramic membrane component, and align the inner surfaces of the two disc-shaped ceramic membrane components together, with the protrusion (2a) of one component correspondingly fitting into the groove (2b) of the other component, and the interval between the inner ends (4b) of the long spokes (4) forming the permeate outlet of the disc-shaped ceramic membrane; align the slot (2c) of the other disc-shaped ceramic membrane component with the other end of the ceramic wedge to achieve the bonding and fixing between the two disc-shaped ceramic membrane components, and obtain a disc-shaped ceramic membrane with a separation membrane layer after drying and calcination.

5. The method for preparing the dish-type ceramic membrane according to claim 4, characterized in that: In step (1), the ceramic powder raw material is one or a combination of alumina, zirconium oxide, titanium oxide, and silicon carbide, and the binder is one or a combination of CMC, HPMC, and lignin, with a mass ratio of ceramic powder raw material: binder: water = 100:0.2-1:50-70; the molding pressure of the compression molding method is 30-50 MPa and the holding time is 30-60 s; the calcination temperature is 1380-1680℃ and the holding time is 1-3 h.

6. The method for preparing the dish-type ceramic membrane according to claim 4, characterized in that: In step (2), the ceramic powder raw material is one or a combination of kaolin, magnesium oxide, quartz, cordierite, mullite, spodumene, and titanium dioxide, and the binder is one or a combination of CMC, HPMC, and lignin, with a mass ratio of ceramic powder raw material: binder: water = 100:0.1~0.5:50~70; the molding pressure of the compression molding method is 10~20MPa, and the holding time is 30~60s.

7. The method for preparing the dish-type ceramic membrane according to claim 4, characterized in that: In step (4), the calcination temperature is 1150-1350℃ and the holding time is 1-3h.

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