CN112156748A - High-strength ceramic silk screen corrugated structured packing and preparation method and application thereof - Google Patents
High-strength ceramic silk screen corrugated structured packing and preparation method and application thereof Download PDFInfo
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Abstract
The invention mainly relates to the field of structured packing, in particular to a corrugated structured packing based on a high-strength ceramic silk screen material, a preparation method and application thereof, and aims to solve the problems that the conventional ceramic silk screen corrugated structured packing is low in overall mechanical strength and cannot realize productization and industrial application. The high-strength ceramic silk screen corrugated structured packing is obtained by systematic solutions of the design of the silk screen structure, the design of the mesh configuration of the silk screen, the design of the corrugated shape, the optimization of the material, the optimization of the preparation process and the like of the ceramic silk screen corrugated structured packing. The ceramic silk screen corrugated structured packing has the characteristics of high strength, large surface area, high efficiency, low pressure drop, chemical corrosion resistance and the like, and solves the problem of low mechanical strength of the whole low-resistance falling rectification packing with high efficiency, high flux and low resistance in a corrosive environment.
Description
The technical field is as follows:
the invention mainly relates to the field of structured packing, in particular to corrugated structured packing based on a high-strength ceramic wire mesh material, a preparation method and application thereof, which are used for various chemical operation processes such as extraction, fractionation, rectification, mixing and the like, can be widely applied to the industrial fields such as oil refining, petrochemical industry, light chemical industry, air separation, trichlorosilane purification, coal chemical industry, food, pharmacy, metallurgy and the like, are particularly suitable for the separation process of systems which are difficult to separate, meet the requirements of high efficiency and low energy consumption, and are particularly suitable for the separation process of various strong corrosive systems.
Background art:
the structured packing represented by the wire mesh has the characteristics of low pressure drop and high mass transfer efficiency, provides high-efficiency and high-flux tower equipment for gas-liquid and liquid-liquid mass transfer processes, and greatly promotes the improvement of the rectification technology. The materials used for the wire mesh structured packing mainly relate to two main types, namely: common alloys represented by stainless steel and special alloys represented by titanium alloy, zirconium alloy, monel, hastelloy. The former has low price and large application amount, but has poor corrosion resistance and is difficult to be used for separating corrosive materials; the latter has obviously better temperature resistance and corrosion resistance than the former, but has high price, and the corrosion resistance to certain high-temperature and high-concentration media needs to be improved. Under the background, the development of efficient, high-flux and low-pressure-drop structured packing suitable for being used in a corrosive environment becomes an important work in the field of chemical materials.
In view of the excellent corrosion resistance of inorganic non-metallic materials such as ceramics, glass and the like, the regular packing of inorganic non-metallic materials such as ceramics, glass and the like is generally regarded by people, and the plate corrugated type inorganic non-metallic regular packing is successfully developed and has good corrosion resistance in application. But compared with the metal wire mesh regular packing, the problems of low separation efficiency, large pressure drop, small operation elasticity and the like are very prominent. Meanwhile, the existing ceramic silk screen has low strength and poor performance, so that the requirement of mechanical strength required by the regular packing of the ceramic silk screen in the rectifying tower cannot be met. The reason is that, besides the brittle fracture of the ceramic itself, the unreasonable selection of the mesh structure design, the material and the preparation method (especially the sintering method) of the ceramic screen is the main reason for the problem. Wherein, the mesh structure of the ceramic silk screen is unreasonable in design, so that the mesh nodes can easily become stress concentration points of external mechanical load and thermal stress generated in the preparation process; the unreasonable selection of the ceramic silk screen material directly causes the low mechanical property of the ceramic silk screen; the common sintering method is accompanied by larger or even larger shrinkage rate, and the characteristic and the thermal stress caused by the superposition of the thermal conductivity coefficient of the silk screen which is lower than that of homogeneous compact materials can amplify the problems caused by the two factors.
The invention content is as follows:
the invention aims to solve the problem of low overall mechanical strength of the conventional ceramic wire mesh corrugated structured packing in the production and practical processes, and provides a corrugated structured packing based on a high-strength ceramic wire mesh material and a preparation method and application thereof.
The technical scheme of the invention is as follows:
a high-strength ceramic silk screen corrugated structured packing basically comprises a corrugated ceramic silk screen material, wherein the silk screen material contains a ceramic material and adjustable-structure silk screen meshes, and the silk screen meshes form adjustable-hole-type-structure silk screen holes; one or more layers of corrugated ceramic wire mesh materials are stacked to form ceramic wire mesh corrugated plates, the stacked ceramic wire mesh corrugated plates are vertically arranged, and planes where wave crests or wave troughs of the corrugated plates are located are parallel to each other; the direction of the wave crest line or the wave trough line of the corrugation has an inclination angle between 15 degrees and 85 degrees with the vertical direction, the inclination angles of the adjacent corrugated plates are the same, and the directions are opposite; the ceramic material, the silk screen mesh structure and the silk screen hole type structure are the same or different.
The regular packing of high strength pottery silk screen ripple, the silk screen that pottery silk screen buckled plate contained is solid or hollow structure by itself, the silk screen pore type structure that pottery silk screen buckled plate contained is one or more than two in circular, oval, conventional polygon, variant polygon, hierarchical polygon, chirality or the anti-hand structure, the ripple shape of pottery buckled plate is one or more than two in following shape: triangular, vertex-smooth triangular, square wave, vertex-smooth square wave, trapezoidal wave, vertex-smooth trapezoidal wave, sinusoidal wave.
The high-strength ceramic silk screen corrugated structured packing has the advantages that the aperture of the silk screen holes of the ceramic silk screen corrugated plates is 2-60 meshes, and the area ratio of the silk screen holes is 50% -95%.
The high-strength ceramic wire mesh corrugated structured packing is characterized in that the ceramic material comprises silicon carbide, silicon nitride, silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxide, yttrium oxide and mullite 3Al2O3·2SiO2SiAlON (SiAlON), AlN, BN, B4One or more than two of C.
The high-strength ceramic silk screen corrugated structured packing has the advantages that the corrugated shape of the ceramic silk screen corrugated plate is one or more than two of a triangle, a smooth triangle at the vertex, a sine wave waveform and a smooth wave, the size and the structure of the corrugation are adjustable, the peak height H is 2-50 mm, and the corrugation angle alpha is 30-150 degrees; if the corrugation is sine wave or smooth wave, the corrugation angle alpha is calculated by the connecting line included angle of the top points of adjacent wave peaks.
The preparation method of the high-strength ceramic silk screen corrugated structured packing comprises the following steps:
preparing a wire mesh corrugated plate:
(1) selecting a single layer or more than two layers of organic silk screens as template materials;
(2) uniformly coating ceramic slurry on an organic material wire mesh by adopting a gas spraying, airless spraying or slurry dipping process, then placing the organic material wire mesh on one surface of a heated split forming die, closing the die, heating, curing and forming to obtain the organic material corrugated plate coated with the ceramic slurry; or adopting a heated corrugated pair roller to extrude, solidify and mold the organic material silk screen coated with the ceramic slurry between the pair roller to obtain the organic material corrugated plate coated with the ceramic slurry, wherein the shape of the corrugation is controlled by the shape of the mold according to the actual condition;
(3) and (3) coating again: continuously and repeatedly coating the organic corrugated plate coated with the ceramic slurry obtained in the step (2) by adopting a gas spraying, airless spraying or slurry dipping process, drying by hot air between two adjacent spraying or dipping processes, and designing and adjusting the circulating coating times of the slurry according to different pore diameters and strength requirements to obtain a precursor of the ceramic silk screen corrugated plate;
(II) stacking and combining more than two ceramic wire mesh corrugated plates to prepare a filler disc unit module:
(1) coating partial or all corrugation peak lines of a ceramic wire mesh corrugated plate precursor with ceramic slurry by using the same ceramic slurry as the ceramic slurry in the step (I) as an adhesive, superposing and combining the ceramic slurry in parallel, and bonding the ceramic slurry of the same kind into a green body of the filler disc unit module;
(2) preprocessing a green body of the packing pan unit module to obtain a sintering precursor of the packing pan unit module;
(3) and processing and molding the sintering precursor of the packing pan unit module into the shape and the size of the required packing pan module, and sintering to obtain the ceramic silk screen corrugated structured packing product.
In the step (1), the organic material silk screen used as the template material is one or more than two of polyethylene, polystyrene, polyurethane, nylon polypropylene, polyvinyl chloride, polyvinyl alcohol and polyether; the mesh hole pattern of the organic material silk screen is one or more than two of a circle, an ellipse, a regular polygon, a variant polygon, a graded polygon, a chiral or anti-chiral structure, and preferably one or more than two of a circle, a triangle, a quadrangle and a hexagon.
In the step (3), different sintering methods are adopted in the sintering process according to different ceramic types, and the silicon carbide material is sintered in an oxide combination mode or a siliconizing reaction sintering process; for oxide-based ceramics: silicon nitride, aluminum oxide, zirconium oxide, magnesium oxide or glass, and sintering by adding sintering aid.
The high-strength ceramic wire mesh corrugated structured packing is applied to the extraction, fractionation, rectification or mixed chemical operation process, and is suitable for petrochemical industry, fine chemical industry, air separation, trichlorosilane purification, coal chemical industry, food, pharmacy or metallurgical industry.
The high-strength ceramic wire mesh corrugated structured packing is applied to the separation process of various strong corrosive systems, and is used for separating and purifying corrosive systems containing sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid or cyclopentanoic acid according to different materials.
The design idea of the invention is as follows:
the existing ceramic silk screen has low strength and poor performance, so that the requirement of mechanical strength required by the regular packing of the ceramic silk screen in a rectifying tower cannot be met. The mesh nodes can easily become stress concentration points when a mechanical load is applied, and the optimized design of the mesh structure of the ceramic mesh screen is beneficial to reducing the stress concentration points; the ceramic wire mesh material and the sintering method thereof are optimized, the sintering shrinkage and the thermal stress generated in the sintering process are regulated and controlled, and the residual stress and microcracks in the sintered product are reduced. Therefore, the invention obtains the high-strength ceramic silk screen corrugated structured packing with direct productization and commercialization values through the systematic solution.
Aiming at the bottleneck problem of low overall mechanical strength of the ceramic wire mesh corrugated structured packing in the production and practical processes, the invention innovatively provides a systematic solution from various aspects such as the wire mesh structure, the wire mesh configuration, the corrugated shape, the material optimization, the preparation process optimization and the like of the ceramic wire mesh corrugated structured packing to obtain the high-strength ceramic wire mesh corrugated structured packing. The ceramic silk screen corrugated structured packing is formed by combining one or more layers of ceramic silk screen corrugated sheets macroscopically, the silk screen is of a solid or hollow structure, the aperture of meshes surrounded by the silk screen is 2-60 meshes (preferably 10-30 meshes), and the area of the meshes accounts for 50% -95%. The novel structured packing can keep the excellent corrosion resistance of inorganic nonmetallic materials, has the separation efficiency and the process operation performance which are not lower than those of the metal wire mesh structured packing, and effectively enlarges the application range of the rectification technology.
The traditional ceramic structured packing is basically solid plate corrugation, a high-strength and high-surface-area wire mesh structure cannot be prepared, and the preparation process has poor controllability, high cost and low efficiency, and the invention develops the high-strength, high-specific-surface, controllable structure, high efficiency and corrosion-resistant ceramic wire mesh corrugation structured packing, which has the following advantages and beneficial effects:
1. the structured packing prepared by the high-strength ceramic silk screen corrugated plate has a large specific surface area which is 5-10 times of the corrugation of a solid plate, so that the structured packing has a high vapor-liquid contact area and high mass transfer efficiency; due to the existence of the wire mesh pore passage, the pressure drop is reduced, and the pressure drop and the separation efficiency are not lower than those of the conventional wire mesh structured packing.
2. The filler is made of a ceramic material, the high chemical stability of strong acid and strong alkali corrosion resistance ensures the long service life of the filler, the maintenance period of equipment can be greatly prolonged, the maintenance cost is saved, the operation is facilitated, and meanwhile, on the premise of meeting the requirement of the same rectification efficiency, the use amount of the existing ceramic solid plate corrugated filler can be greatly reduced, the tower height is reduced, and the equipment investment cost is reduced.
3. The novel high-strength ceramic silk screen corrugated structured packing is prepared by taking an organic high-molecular silk screen as a template, impregnating slurry to obtain a corrugated plate shape suitable for the structural requirement of the packing, assembling the corrugated plate shape into a packing tray, and performing pyrolysis sintering.
Description of the drawings:
fig. 1(a) -1 (b) are schematic views illustrating the assembly of the corrugated board of the present invention. Wherein fig. 1(a) is a vertical schematic view of a single sheet of wire mesh corrugated board; FIG. 1(b) is a schematic diagram showing the vertical arrangement and superposition of a plurality of corrugated plates of a silk screen.
Fig. 2(a) -2 (b) show the hole pattern structure of the high-strength two-dimensional ceramic screen material of the present invention. Wherein, fig. 2(a) is a circle; fig. 2(b) is an oval shape.
Fig. 3(a) -3 (c) are screen hole pattern structures of the high strength two-dimensional ceramic screen material of the present invention-conventional polygonal structures: FIG. 3(a) is a trilateral; FIG. 3(b) is a quadrilateral; FIG. 3(c) is a regular hexagon; wherein a and b represent the respective feature sizes, and α represents the angle between the feature sizes.
Fig. 4(a) -fig. 4(f) are screen hole type structures of the high strength two-dimensional ceramic screen material of the present invention-special (variant) polygonal structures: FIG. 4(a) is a four-bladed polygon; FIG. 4(b) is a hexagon; FIG. 4(c) is a double reentrant hexagonal shape; FIG. 4(d) is a regular hexagon + double reentrant corner hexagon; FIG. 4(e) is a single reentrant hexagonal shape; FIG. 4(f) is a regular triangle + regular hexagon; wherein a, b, c represent the respective feature sizes, and α represents the included angle between the feature sizes.
Fig. 5(a) -5 (c) are screen hole type structures-hierarchical polygonal structures of the high strength two-dimensional ceramic screen material of the present invention: FIG. 5(a) is a graded hexagon; FIG. 5(b) is a hierarchical quadrilateral; FIG. 5(c) is a hierarchical trilateral; wherein a, b, c represent the respective characteristic dimensions.
Fig. 6(a) -6 (e) are screen hole type structures-special (variant) polygonal structures of the high strength two-dimensional ceramic screen material of the present invention: FIG. 6(a) is a third-order chiral structure; FIG. 6(b) is a fourth-order chiral structure; FIG. 6(c) is a sixth-order chiral structure; FIG. 6(d) is a third order anti-chiral structure; FIG. 6(e) is a fourth order anti-chiral structure; wherein a and r represent the respective characteristic dimensions.
Fig. 7(a) -7 (g) show the kind of the corrugated shape S of the corrugated sheet in the high-strength two-dimensional ceramic mesh material according to the present invention. Wherein, fig. 7(a) is a triangular corrugation, H represents a peak height, α represents a corrugation angle, and l represents a wave distance; FIG. 7(b) is a triangle with rounded vertices, H represents the peak height, α represents the corrugation angle, and l represents the wave distance; FIG. 7(c) is a square waveform; FIG. 7(d) is a top rounded square waveform; FIG. 7(e) is a trapezoidal waveform; FIG. 7(f) is a top rounded trapezoidal waveform; fig. 7(g) shows a sine wave waveform.
FIGS. 8(a) -8 (b) show the corrugated structured packing of ceramic mesh (mesh diameter of 30 mesh, made of siliconized silicon carbide) according to the present invention. Wherein, fig. 8(a) is a real object diagram of a 30-mesh wire mesh corrugated plate; FIG. 8(b) is a block diagram of a 30 mesh wire mesh corrugated packing.
FIGS. 9(a) to 9(b) show the corrugated structured packing of ceramic mesh according to the present invention (mesh diameter is 10 mesh, and the material is alumina). Wherein, fig. 9(a) is a 10-mesh silk screen corrugated plate object diagram; FIG. 9(b) is a block diagram of a 10 mesh wire mesh corrugated packing.
Figure 10 is a photograph of a Φ 3000mm packing cup.
The specific implementation mode is as follows:
in the specific implementation process, the ceramic wire mesh corrugated plates with the corrugated geometric shapes are superposed and combined to form a filler disc structure; the corrugated plates in the packing disc are vertically arranged, the plates are mutually parallel and overlapped, the parallel direction of the corrugations and the vertical direction of the packing disc have an inclination angle of 15-85 degrees (preferably 40-70 degrees), and the inclination angles of the adjacent corrugated plates are the same and opposite in direction. The organic silk screen is coated with ceramic slurry and then is subjected to compression molding or double-roller extrusion molding to obtain a silk screen corrugated plate precursor, and then the silk screen corrugated plate precursor is coated to the required surface density and assembled into a filler disc (block), and then the filler disc (block) is pyrolyzed and sintered to obtain the ceramic silk screen corrugated structured filler.
As shown in fig. 7(a) -7 (b), the corrugated plate of the novel corrosion-resistant high-strength ceramic wire mesh corrugated structured packing provided by the invention is triangular or smooth-vertex triangular, and has the functions of increasing resistance to mechanical load and reducing stress concentration at the vertex of the triangular corrugation; the ripple size structure is adjustable, the wave peak height (H) can be between 2-50 mm (preferably 3-15 mm), the ripple angle alpha can be between 30-150 degrees (preferably 60-90 degrees), if the ripple shape is smooth wave, the ripple angle alpha is calculated by the connecting line included angle of the top points of adjacent wave peaks.
As shown in fig. 7(c) -7 (g), the kind of the corrugated shape S of the corrugated sheet in the high-strength two-dimensional ceramic mesh material of the present invention. Wherein, fig. 7(c) is a square wave waveform, which functions to realize a square wave type corrugated plate; FIG. 7(d) is a top-rounded square waveform for reducing stress concentration at the top of the square-wave corrugated board; fig. 7(e) is a trapezoidal wave shape, which functions to realize a trapezoidal wave type corrugated plate; FIG. 7(f) is a top-rounded trapezoidal waveform for reducing the stress concentration at the top of the corrugated board; fig. 7(g) is a sine wave waveform, and functions to realize a sine wave type corrugated plate.
As shown in fig. 2 to 6, the mesh shape of the wire mesh corrugated plate is as follows:
as shown in fig. 2(a) -2 (b), the screen hole type structure of the high strength two-dimensional ceramic screen material of the present invention. Wherein, FIG. 2(a) is a circle, which has the function of realizing the close packing of circular meshes; FIG. 2(b) is an oval shape, which functions to achieve close packing or oriented packing of oval shaped meshes.
As shown in fig. 3(a) -3 (c), the screen hole type structure of the high-strength two-dimensional ceramic screen material of the present invention, the conventional polygonal structure: FIG. 3(a) is a trilateral shape, which functions to achieve triangular mesh and its close packing; FIG. 3(b) is a quadrilateral shape, the purpose of which is to achieve rectangular meshes and their close packing; fig. 3(c) is a regular hexagon, which functions to achieve a regular hexagonal mesh and its close packing.
As shown in fig. 4(a) -4 (f), the screen hole type structure of the high-strength two-dimensional ceramic screen material of the present invention, a special (variant) polygonal structure: FIG. 4(a) is a four-bladed polygon, whose function is to achieve anisotropic mesh and close packing; FIG. 4(b) is a hexagon, which functions to realize a regular hexagonal mesh; FIG. 4(c) is a double reentrant hexagonal pattern which functions to achieve a double reentrant hexagonal mesh; FIG. 4(d) is a regular hexagon + double reentrant hexagon, which functions to realize the combination of regular hexagonal meshes and double reentrant hexagonal meshes; FIG. 4(e) is a single reentrant hexagonal pattern which functions to achieve a single reentrant hexagonal mesh; fig. 4(f) is a regular triangle + a regular hexagon, and the function of the mesh is to realize the combination of the regular triangle mesh and the regular hexagon mesh.
As shown in fig. 5(a) -5 (c), the screen hole type structure of the high-strength two-dimensional ceramic screen material of the present invention, a hierarchical polygonal structure: FIG. 5(a) is a stepped hexagon, which functions to achieve two-level hexagonal meshes and reduce node stress; FIG. 5(b) is a hierarchical quadrilateral whose role is to realize two-level quadrilateral meshes and reduce node stress; fig. 5(c) is a stepped trilateral mesh which functions to achieve a two-level trilateral mesh and reduce nodal stress.
As shown in fig. 6(a) -6 (e), the screen hole type structure of the high-strength two-dimensional ceramic screen material of the present invention, a special (variant) polygonal structure: FIG. 6(a) is a third-order chiral structure, which functions to achieve a third-order chiral mesh and reduce nodal stress; FIG. 6(b) is a fourth-order chiral structure, which is used to realize a fourth-order chiral mesh and reduce node stress; FIG. 6(c) is a sixth-order chiral structure, which functions to achieve a sixth-order chiral mesh and reduce nodal stress; FIG. 6(d) is a third-order anti-chiral structure, which functions to achieve a third-order anti-chiral mesh and reduce nodal stress; FIG. 6(e) is a fourth-order anti-chiral structure, which functions to achieve a fourth-order anti-chiral mesh and reduce nodal stress.
The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Example 1
In this embodiment, the preparation method of the high-strength siliconized silicon carbide wire mesh corrugated structured packing is as follows:
firstly, the slurry is coated on the organic nylon wire mesh in an airless spraying manner, and then the precursor of the corrugated plate of the ceramic wire mesh is prepared according to the corresponding geometric characteristics (see table 1). Then, the same slurry is used as an adhesive, the screen corrugated plate precursors are parallelly overlapped and combined to form a filler disc structure, and the ceramic screen corrugated regular filler is obtained by means of thermal decomposition, combination, addition molding and sintering after bonding according to the requirements of the regular filler structure. In the preparation process of the regular packing of pottery silk screen ripple, once only connect into the packing pan with pottery silk screen buckled plate precursor, the packing pan diameter is 100mm, and the dish height is 100mm, and the buckled plate combines firmly, and the installation is easy, stable in structure. The apparent compressive strength (force that can be withstood per unit macroscopic area) of the packing cup is 30 MPa.
In this embodiment, the preparation process of the high-strength silicon carbide wire mesh corrugated board precursor is as follows:
the mass ratio is 60%: 35%: 5% of silicon carbide powder with the average particle size of 5 mu m, phenolic resin and p-toluenesulfonic acid are dissolved in absolute ethyl alcohol together, and the mixture is mechanically stirred, ball-milled and filtered to obtain slurry, wherein the solid content of the slurry solution is 80% of the total mass. The raw material is uniformly sprayed on three pore size polyurethane silk screens (10 meshes, 30 meshes and 60 meshes respectively) in a corrugated shape, and the surface density (the mass of a silk screen corrugated plate precursor in unit macroscopic area) is controlled to be 0.03g/cm2Then spreading the coated silk screen on one surface of a split mold which is heated to 120 ℃ and provided with triangular grooves, closing the mold and pressurizing to a limit position, limiting the position between the molds to ensure that the gap is 0.5mm, preserving heat for 20 seconds and then curing, or extruding and curing the coated silk screen between double rollers to form the coated silk screen into the same corrugated shape with the double-roller mold, spraying the coated silk screen to a certain surface density after opening the mold,the surface density is controlled to be 0.1g/cm2But ensuring that the pore of the silk screen is opened, drying and curing at 150 ℃ to obtain the silicon carbide silk screen corrugated board precursor.
As shown in fig. 1(a) to 1(b), the packing cup is prepared as follows: a plurality of corrugated plate precursors are stacked and bonded to form a plate block, corrugated plates in the plate block are vertically arranged, the plates are stacked in parallel, an inclination angle theta is formed between the parallel direction of the corrugations and the vertical direction, the inclination angle theta is between 15 degrees and 85 degrees (60 degrees or 45 degrees in the embodiment), the inclination angles of adjacent corrugated plates are the same, the directions are opposite, and contact points between two adjacent corrugated plates are bonding points.
In this example, the pyrolysis process is as follows:
and heating the combined and bonded packing disc to 800 ℃ under the protective atmosphere of argon, preserving the heat for 1 hour at the heating rate of 5 ℃ per minute, and generating the carbon silk screen corrugated structured packing disc.
In this embodiment, the sintering process includes:
and (3) carrying out reactive infiltration sintering on the carbon silk screen corrugated regular packing disc obtained by pyrolysis, wherein silicon is used as a raw material in the infiltration reactive sintering, the sintering is carried out under the vacuum condition, the heating rate is 15 ℃ per minute, the melt temperature is 1600 ℃, and the heat preservation is carried out for 1 hour to obtain the silicon carbide silk screen corrugated regular packing. Silicon is selected as a raw material in the reactive sintering infiltration, and the silicon carbide silk screen corrugated structured packing is obtained after the Si infiltration. As shown in fig. 8(a) -8 (b), the macro-morphology and structure of the high-strength siliconized silicon carbide wire mesh corrugated plate and the corresponding high-strength siliconized silicon carbide wire mesh corrugated packing block are regular as shown in fig. 8, and the high-strength siliconized silicon carbide wire mesh corrugated packing block is formed by mutually overlapping a plurality of vertex smooth triangular corrugated plates, contains a large number of quadrilateral meshes on the corrugated plates, and has a large geometric surface area.
In this embodiment, the obtained silicon carbide wire mesh corrugated structured packing is formed by superposing and combining silicon carbide wire mesh corrugated plates with corrugated geometric shapes, each corrugated plate is a silicon carbide wire mesh with a three-dimensional connected network structure, and the corrugated shape of each corrugated plate is a triangle. The specific parameters are shown in Table 1.
TABLE 1 data of the geometric structural characteristics of the high-strength silicon carbide screen corrugated structured packing and wire mesh (BX500) of the present invention
The filler is subjected to cold film and hot film experiments on a small rectification experimental device, the hydrodynamic property and the mass transfer property of the filler are researched, and the method specifically comprises the following operations:
the silicon carbide wire mesh corrugated structured packing is stacked in a rectification experimental tower in a vertical crossing mode by the upper and lower layer unit plates, experimental research is carried out by utilizing an alcohol-water binary system, the experimental process is total reflux operation, and comparison is carried out with the BX structured packing (BX type wire mesh corrugated packing, the material is 316L) which is most applied and has the highest efficiency in the existing industry.
The experimental result shows that the theoretical plate number of the silicon carbide screen corrugated regular I-type filler under different spray densities is higher than that of the BX filler; experimental tests show that the pressure drop of the silicon carbide screen corrugated structured packing is obviously smaller than that of BX packing, and the amplitude reduction reaches more than 25%. The specific parameters are shown in Table 2.
TABLE 2 comparison of theoretical plate number of structured packing with high-strength silicon carbide screen and BX wire mesh packing
In the present embodiment, only the high strength silicon carbide mesh corrugated structured packing is listed, and the mesh aperture, the organic mesh material, the ceramic material, etc. are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Example 2
The present embodiment is a preparation and application of a corrugated structured packing based on a high-strength alumina ceramic mesh material, and is different from embodiment 1 in that:
the preparation process of the corrugated silk screen structured packing made of the alumina material comprises the following steps: the mass ratio is respectively 80%: 15%: 5% of alumina powder with the average particle size of 5 mu m, 2 mu m of silica powder and polyvinyl alcohol (PVA) are blended in distilled water, and are mechanically stirred, ball-milled and filtered to obtain slurry, wherein the solid content of the slurry solution is 85% of the total mass. The raw material is uniformly sprayed on a corrugated nylon wire mesh with three apertures (10 meshes, 30 meshes and 60 meshes respectively), and the areal density is controlled to be 0.03g/cm2Spreading the coated wire mesh on one surface of a split mold heated to 160 ℃ and provided with triangular grooves, closing the mold and pressurizing to a limiting position, limiting the position between the molds to ensure that the gap is 0.5mm, keeping the temperature for 20 seconds, shaping and curing, or extruding and curing the coated wire mesh between double rollers to form the wire mesh with the same corrugated shape as the double-roller mold, spraying the obtained wire mesh corrugated plate to a certain surface density again after opening the mold, wherein the surface density is controlled to be 0.1g/cm2But the opening of the pore canal of the wire mesh is ensured, and the drying is carried out at 160 ℃ to obtain the precursor of the corrugated plate of the alumina wire mesh.
As shown in fig. 1(a) -1 (b), the packing cup is prepared as follows: the same slurry of multi-sheet corrugated plate precursor is overlapped and bonded into a plate block, the corrugated plates in the plate block are vertically arranged, the plates are mutually overlapped in parallel, an inclination angle theta is formed between the parallel direction of the corrugated plates and the vertical direction, the inclination angles of the adjacent corrugated plates are the same between 15 degrees and 85 degrees (60 degrees or 45 degrees in the embodiment), the directions are opposite, and contact points between the two adjacent corrugated plates are bonding points.
In this embodiment, the sintering process includes:
and heating the combined and bonded packing disc to 1500 ℃ in an air atmosphere, preserving the heat for 1.5 hours at a heating rate of 5 ℃ per minute, and thus obtaining the alumina wire mesh corrugated structured packing disc. The apparent compressive strength (force per unit macroscopic area) of the packing cup was 40 MPa. As shown in fig. 9(a) -9 (b), the macro-morphology and the structure of the high-strength alumina wire mesh corrugated plate and the corresponding high-strength alumina wire mesh corrugated filler block are respectively shown in fig. 9, and it can be seen from fig. 9 that the high-strength alumina wire mesh corrugated filler block has a regular structure and is formed by mutually overlapping a plurality of smooth triangular corrugated plates with smooth vertexes, and the corrugated plates contain a large number of elliptical meshes and have a large geometric surface area.
In this embodiment, the obtained alumina wire mesh corrugated structured packing is formed by stacking and combining alumina wire mesh corrugated plates with corrugated geometric shapes, each corrugated plate is an alumina wire mesh with a three-dimensional connected network structure, and the corrugated shape of each corrugated plate is a triangle. The specific parameters are shown in Table 3.
TABLE 3 data of the geometric structural characteristics of the high-strength alumina wire mesh corrugated structured packing of the present invention and wire mesh (BX500)
The filler is subjected to cold film and hot film experiments on a small rectification experimental device, the hydrodynamic property and the mass transfer property of the filler are researched, and the method specifically comprises the following operations:
the high-strength alumina wire mesh corrugated structured packing obtained in the embodiment is stacked in a rectification experimental tower in a manner that the upper and lower layer unit plates are vertically crossed, experimental research is carried out by using an alcohol-water binary system, the experimental process is total reflux operation, and comparison is carried out with the BX structured packing (BX type wire mesh corrugated packing, material is 316L) which is most applied and has the highest efficiency in the existing industry.
The experimental result shows that the alumina II type filler is 20-50% higher than the BX filler; experiment tests show that the pressure drop of the high-strength alumina wire mesh corrugated regular packing is obviously smaller than that of BX packing, and the pressure drop reduction amplitude reaches 15%. The specific parameters are shown in Table 4.
TABLE 4 comparison of theoretical plate number of corrugated structured packing of high-strength alumina wire mesh of the present invention with BX wire mesh packing
In the present embodiment, only the high strength silicon carbide mesh corrugated structured packing is listed, and the mesh aperture, the organic mesh material, the ceramic material, etc. are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Example 3
The present embodiment is a preparation and application of a corrugated structured packing based on a high-strength alumina ceramic mesh material, and is different from embodiment 2 in that:
the alumina wire mesh corrugated II type structured packing with the diameter of 315 multiplied by 200mm is prepared, a pilot scale experiment is carried out on a pilot scale rectifying tower, and compared with the metal wire mesh BX structured packing (the material is 316L), the adopted experimental material is 10 wt% of alcohol water solution, the heights of the two types of packing are both 2 meters, and the total reflux operation shows that the theoretical plate number of the BX structured packing is 2.9 blocks/m, and the alumina wire mesh corrugated II type structured packing can reach 4.0 blocks/m and is improved by more than 37%. The apparent compressive strength (force that can be withstood per unit macroscopic area) of the packing cup was 45 MPa.
Example 4
This example is an evaluation of the performance of the corrugated structured packing based on high strength ceramic mesh material of the present invention. In particular to the corrosion resistance research of the high-strength ceramic silk screen corrugated structured packing, the result is as follows:
(1) the corrosion resistance of the material is researched and compared by adopting HCl as a medium, three hydrochloric acids with different concentrations (5 wt%, 10 wt% and 20 wt% respectively) are prepared, and after silicon carbide, aluminum oxide, silicon oxide screen mesh corrugated regular packing and BX packing (316L) are soaked in three solutions with different concentrations for three weeks, the mass change rates before and after measurement show that the ceramic screen mesh corrugated regular packing is not corroded, the BX packing (316L) has obvious weight loss, and local areas are corroded and even have holes.
(2) By means of H2SO4The corrosion resistance of the material is researched and compared as a medium, three sulfuric acids with different concentrations (5 wt%, 20 wt% and 35 wt% respectively) are prepared, silicon carbide, aluminum oxide and silicon oxide are taken, the silk screen corrugated regular packing and the BX packing (316L) are soaked in three solutions with different concentrations for three weeks, and the mass change rate before and after measurement shows that the three silk screen corrugated regular packing do not generate corrosion resistanceThe corrosion was generated, and the BX filler (316L) lost significant weight, and voids appeared.
(3) By HNO3The corrosion resistance of the material is researched and compared as a medium, three kinds of nitric acid with different concentrations (5 wt%, 10 wt% and 20 wt% respectively) are prepared, silicon carbide, aluminum oxide and silicon oxide are taken, and after the wire mesh corrugated structured packing and the BX packing (316L) are soaked in three kinds of solutions with different concentrations for three weeks, the mass change rates before and after the measurement show that the three kinds of ceramic wire mesh corrugated structured packing are not corroded, the weight loss of the BX packing (316L) is obvious, and a local area disappears.
(4) The corrosion resistance of the material is researched and compared by adopting HF as a medium, hydrofluoric acid with the concentration of 10 wt% is prepared, and after the silicon carbide wire mesh corrugated regular packing and 904L, titanium alloy (TC4) and Hastelloy material packing are soaked in the solution for three weeks, the mass change rate before and after measurement shows that the silicon carbide wire mesh corrugated regular packing is not corroded, and the other three kinds of packing are completely dissolved.
As shown in fig. 7, in the corrugated plates of the ceramic wire mesh corrugated structured packing (wire mesh aperture 30 and 10 meshes), the corrugated shape and structure are abundant; as shown in fig. 2 to 6, the mesh holes are through, and the mesh holes are rich in meshes. The filler prepared by the invention has larger specific surface, liquid phase is easy to coat and form a film on the surface of the wire mesh rib, gas phase can pass through the wire mesh hole, and the gas-liquid exchange is sufficient, so the invention has low pressure drop and high separation efficiency.
As shown in FIG. 10, a photograph of a filler disc with a diameter of 3000mm shows that the filler prepared by the method can be changed into a large filler disc in an assembly mode, so that the installation requirement of a large-size tower is met.
The embodiment shows that the high-strength ceramic silk screen corrugated plates with the corrugated geometric shapes are superposed and combined, the high-strength ceramic silk screen regular corrugated plates well keep the network characteristics of the organic silk screen, and have the characteristics of large specific surface area, thin wall, high strength, controllable structure and high chemical stability.
Claims (10)
1. A high-strength ceramic silk screen corrugated structured packing is characterized in that the ceramic silk screen corrugated structured packing basically comprises a corrugated ceramic silk screen material, the silk screen material contains a ceramic material and adjustable-structure silk screen meshes, and the silk screen meshes form adjustable-hole-structure silk screen holes; one or more layers of corrugated ceramic wire mesh materials are stacked to form ceramic wire mesh corrugated plates, the stacked ceramic wire mesh corrugated plates are vertically arranged, and planes where wave crests or wave troughs of the corrugated plates are located are parallel to each other; the direction of the wave crest line or the wave trough line of the corrugation has an inclination angle between 15 degrees and 85 degrees with the vertical direction, the inclination angles of the adjacent corrugated plates are the same, and the directions are opposite; the ceramic material, the silk screen mesh structure and the silk screen hole type structure are the same or different.
2. The high-strength ceramic wire mesh corrugated structured packing as claimed in claim 1, wherein the wire mesh of the ceramic wire mesh corrugated plate is of a solid or hollow structure, the wire mesh pattern of the ceramic wire mesh corrugated plate is of one or more than two of a circular, oval, regular polygon, modified polygon, graded polygon, chiral or anti-chiral structure, and the corrugation shape of the ceramic wire mesh corrugated plate is of one or more than two of the following shapes: triangular, vertex-smooth triangular, square wave, vertex-smooth square wave, trapezoidal wave, vertex-smooth trapezoidal wave, sinusoidal wave.
3. The high-strength ceramic wire mesh corrugated structured packing as claimed in claim 1, wherein the wire mesh aperture diameter of the ceramic wire mesh corrugated plate is 2-60 mesh, and the wire mesh aperture area ratio is 50-95%.
4. The high strength ceramic wire mesh corrugated structured packing of claim 1,the ceramic material comprises silicon carbide, silicon nitride, silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxide, yttrium oxide, and mullite 3Al2O3·2SiO2SiAlON (SiAlON), AlN, BN, B4One or more than two of C.
5. The high-strength ceramic wire mesh corrugated structured packing as claimed in claim 1, wherein the corrugated shape of the ceramic wire mesh corrugated plate is one or more of a triangle, a vertex smooth triangle, a sine wave waveform and a smooth wave, the corrugation size and structure are adjustable, the peak height H is between 2 mm and 50mm, and the corrugation angle α is between 30 ° and 150 °; if the corrugation is sine wave or smooth wave, the corrugation angle alpha is calculated by the connecting line included angle of the top points of adjacent wave peaks.
6. The method for preparing the high-strength ceramic wire mesh corrugated structured packing as claimed in any one of claims 1 to 5, comprising the steps of:
preparing a wire mesh corrugated plate:
(1) selecting a single layer or more than two layers of organic silk screens as template materials;
(2) uniformly coating ceramic slurry on an organic material wire mesh by adopting a gas spraying, airless spraying or slurry dipping process, then placing the organic material wire mesh on one surface of a heated split forming die, closing the die, heating, curing and forming to obtain the organic material corrugated plate coated with the ceramic slurry; or adopting a heated corrugated pair roller to extrude, solidify and mold the organic material silk screen coated with the ceramic slurry between the pair roller to obtain the organic material corrugated plate coated with the ceramic slurry, wherein the shape of the corrugation is controlled by the shape of the mold according to the actual condition;
(3) and (3) coating again: continuously and repeatedly coating the organic corrugated plate coated with the ceramic slurry obtained in the step (2) by adopting a gas spraying, airless spraying or slurry dipping process, drying by hot air between two adjacent spraying or dipping processes, and designing and adjusting the circulating coating times of the slurry according to different pore diameters and strength requirements to obtain a precursor of the ceramic silk screen corrugated plate;
(II) stacking and combining more than two ceramic wire mesh corrugated plates to prepare a filler disc unit module:
(1) coating partial or all corrugation peak lines of a ceramic wire mesh corrugated plate precursor with ceramic slurry by using the same ceramic slurry as the ceramic slurry in the step (I) as an adhesive, superposing and combining the ceramic slurry in parallel, and bonding the ceramic slurry of the same kind into a green body of the filler disc unit module;
(2) preprocessing a green body of the packing pan unit module to obtain a sintering precursor of the packing pan unit module;
(3) and processing and molding the sintering precursor of the packing pan unit module into the shape and the size of the required packing pan module, and sintering to obtain the ceramic silk screen corrugated structured packing product.
7. The method for preparing the high-strength ceramic wire mesh corrugated structured packing as claimed in claim 6, wherein in the step (1), the organic wire mesh used as the template material is made of one or more of polyethylene, polystyrene, polyurethane, nylon-polypropylene, polyvinyl chloride, polyvinyl alcohol and polyether; the mesh hole pattern of the organic material silk screen is one or more than two of a circle, an ellipse, a regular polygon, a variant polygon, a graded polygon, a chiral or anti-chiral structure, and preferably one or more than two of a circle, a triangle, a quadrangle and a hexagon.
8. The method for preparing the high-strength ceramic wire mesh corrugated structured packing as claimed in claim 6, wherein in the step (3) of the second step, different sintering methods are adopted in the sintering process according to different ceramic types, and the silicon carbide material is sintered by an oxide bonding method or a siliconizing reaction sintering process; for oxide-based ceramics: silicon nitride, aluminum oxide, zirconium oxide, magnesium oxide or glass, and sintering by adding sintering aid.
9. The application of the high-strength ceramic wire mesh corrugated structured packing according to any one of claims 1 to 5, wherein the ceramic wire mesh corrugated structured packing is applied to extraction, fractionation, rectification or mixed chemical operation processes, and is suitable for petrochemical, fine chemical, air separation, trichlorosilane purification, coal chemical, food, pharmaceutical or metallurgical industries.
10. The use of the high-strength ceramic wire mesh corrugated structured packing as claimed in claim 9, wherein the ceramic wire mesh corrugated structured packing is used in the separation process of various strong corrosion systems, and is used for separation and purification of corrosion systems containing sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid or cyclopentanoic acid according to different materials.
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