CN112973616A

CN112973616A - High-strength polytetrafluoroethylene silk screen corrugated structured packing and preparation method and application thereof

Info

Publication number: CN112973616A
Application number: CN202110351557.XA
Authority: CN
Inventors: 陈肯; 陈凌云; 陈骑冲
Original assignee: Biaotao Technology Shanghai Co ltd
Current assignee: Biaotao Technology Shanghai Co ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-06-18

Abstract

The invention mainly relates to the field of structured packing, in particular to a corrugated structured packing of a high-strength polytetrafluoroethylene silk screen material based on a metal inner core, a preparation method and application thereof, and aims to solve the problems that the conventional polytetrafluoroethylene corrugated structured packing is low in overall exchange efficiency and mechanical strength, cannot form a silk screen structure, and can realize productization and industrial application. The high-strength polytetrafluoroethylene silk screen corrugated structured packing is obtained by systematic solutions of metal silk screen structure design, mesh configuration design, corrugated shape design, metal core material optimization, preparation process optimization and the like of the polytetrafluoroethylene silk screen corrugated structured packing. The polytetrafluoroethylene silk screen corrugated structured packing has the characteristics of high strength, large surface area, high efficiency, low pressure drop, chemical corrosion resistance, high temperature 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 strong corrosion environment.

Description

High-strength polytetrafluoroethylene silk screen corrugated structured packing and preparation method and application thereof

Technical Field

The invention mainly relates to the field of structured packing, in particular to corrugated structured packing based on a high-strength polytetrafluoroethylene silk screen 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

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.

Polytetrafluoroethylene (F4, PTFE) is commonly called "the king of plastics", and has a series of excellent use properties: the high temperature resistance, the long-term use temperature of 200-260 ℃, the low temperature resistance, and the softness at-100 ℃; corrosion resistance-resistance to strong acid and strong base and all organic solvents; weather resistance — optimum aging life in plastics; high lubrication-with the lowest coefficient of friction in plastics (0.04); non-stick-having minimal surface tension in solid materials without sticking any substances; no toxicity, physiological inertia; in view of the excellent corrosion resistance of polytetrafluoroethylene, polytetrafluoroethylene has been generally regarded as a regular packing and has achieved a good corrosion resistance effect in application. Compared with the metal wire mesh structured packing, the polytetrafluoroethylene structured packing has the advantages of low separation efficiency, large pressure drop, small operation elasticity, no high temperature resistance, easy deformation and the like, the existing polytetrafluoroethylene structured packing has low strength, low exchange efficiency, poor thermal deformation and high temperature performance, and cannot manufacture the wire mesh structured packing, so that the conventional polytetrafluoroethylene structured packing cannot meet the mechanical strength requirement, the exchange efficiency, the high temperature performance and the stability of the structured packing required by the filling of the structured packing in a rectifying tower, and the low strength of the polytetrafluoroethylene is a main reason for causing the problem and directly causes the low mechanical performance of the polytetrafluoroethylene structured packing; the common processing method is to simply bundle or thread the perforated polytetrafluoroethylene corrugated plates together by using a screw, which further amplifies the problems caused by the two factors, particularly the corrugated plates expand and become straight after high temperature, and even the gas-liquid exchange function is lost.

Disclosure of Invention

In order to solve the problems of low overall mechanical strength, low exchange efficiency, high-temperature deformation failure and the like of the conventional polytetrafluoroethylene corrugated structured packing in the production and practical processes, the invention aims to provide a corrugated structured packing based on a high-strength polytetrafluoroethylene wire mesh material and a preparation method and application thereof. Through the structural design of the mesh, the mesh configuration design of the mesh, the design of the corrugated shape, the optimization of the material and the optimization of the preparation process, the solid corrugated mesh structured packing for the packed tower is further assembled to adapt to the high-efficiency and high-flux rectification separation of corrosive materials under the low resistance reduction.

The technical scheme of the invention is as follows:

a high-strength polytetrafluoroethylene silk screen corrugated structured packing is basically composed of a corrugated polytetrafluoroethylene silk screen material, wherein the silk screen material is provided with a metal core material, the core material is composed of single-stranded metal wires or multi-stranded metal wires, the core material is coated with the polytetrafluoroethylene material, and the silk screen meshes form mesh holes with adjustable hole pattern structures; one or more layers of corrugated polytetrafluoroethylene wire mesh materials with metal core materials are superposed to form polytetrafluoroethylene wire mesh corrugated plates, the superposed polytetrafluoroethylene wire mesh corrugated plates are vertically arranged, and planes of wave crests or wave troughs of the corrugated plates 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 material of the metal core material of the mesh, the mesh structure of the mesh and the hole-hole structure of the mesh are the same or different.

The regular packing of high strength polytetrafluoroethylene silk screen ripple, the solid construction of the silk screen of self for having the outer parcel polytetrafluoroethylene of metal core that polytetrafluoroethylene silk screen buckled plate contained, the silk screen hole pass structure that polytetrafluoroethylene 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 polytetrafluoroethylene 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 polytetrafluoroethylene silk screen corrugated structured packing is characterized in that the aperture of a silk screen hole of a polytetrafluoroethylene silk screen corrugated plate is 2-60 meshes, and the area ratio of the silk screen hole is 50% -95%.

The high-strength polytetrafluoroethylene silk screen corrugated structured packing is characterized in that the polytetrafluoroethylene silk screen inner core material contains one or more than two of aluminum-based alloy, stainless steel, iron-based, nickel-based and copper-based metals.

The high-strength polytetrafluoroethylene silk screen corrugated structured packing is characterized in that the polytetrafluoroethylene silk screen corrugated plate has one or more than two of triangular shape, smooth triangular shape at the vertex, sine wave shape and smooth wave shape, the corrugated size and structure are adjustable, the wave 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 polytetrafluoroethylene wire mesh corrugated structured packing comprises the following steps:

step one, preparing a wire mesh corrugated plate:

step 101, selecting a single-layer or multi-layer welded metal wire mesh as a template material;

step 102, uniformly coating polytetrafluoroethylene slurry on a metal wire mesh by adopting a gas spraying, airless spraying or slurry dipping process, and then putting the metal wire mesh into a heating furnace for heating, curing and forming to obtain a metal corrugated plate coated with the polytetrafluoroethylene slurry; the shape of the corrugations is determined by the shape of the wire mesh according to the actual situation;

step 103, recoating: step 102, the metal corrugated plate coated with the polytetrafluoroethylene slurry is continuously coated with the slurry repeatedly by adopting a gas spraying, airless spraying or slurry dipping process, the slurry is dried by hot air between two adjacent spraying or dipping processes, and the circulating coating times of the slurry are designed and adjusted according to different pore diameters and strength requirements, so that a precursor of the polytetrafluoroethylene silk screen corrugated plate is obtained;

step two, laminating and combining polytetrafluoroethylene wire mesh corrugated plates above sheets to prepare a filler disc unit module:

step 201, using polytetrafluoroethylene slurry as the adhesive in the first step, coating polytetrafluoroethylene slurry on part or all of the corrugation crest lines of the precursor of the polytetrafluoroethylene wire mesh corrugated plate, superposing and combining the polytetrafluoroethylene slurry in parallel, and bonding the polytetrafluoroethylene slurry of the same kind into a green body of the filler tray unit module;

step 202, preprocessing a green body of the packing pan unit module to obtain a heating precursor of the packing pan unit module;

and 203, processing and molding the heating precursor of the packing pan unit module into the shape and the size of the required packing pan module, and heating at high temperature to obtain the polytetrafluoroethylene silk screen corrugated structured packing product.

In the step 101, the metal machine material silk screen used as the template material is one or more than two of stainless steel, aluminum alloy, titanium alloy, Monel and Hastelloy; the mesh hole pattern of the metal wire mesh 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 preparation method of the high-strength polytetrafluoroethylene wire mesh corrugated structured packing, in step 203, different heating methods are adopted in the heating process according to different polytetrafluoroethylene thicknesses.

The high-strength polytetrafluoroethylene silk screen 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 polytetrafluoroethylene 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 polytetrafluoroethylene silk screen has low strength and poor performance, so that the polytetrafluoroethylene silk screen regular packing cannot be manufactured, and the requirement on mechanical strength required by the packing in the rectifying tower is met. Therefore, the invention obtains the high-strength polytetrafluoroethylene wire mesh 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 polytetrafluoroethylene 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 polytetrafluoroethylene wire mesh corrugated structured packing, and obtains the high-strength polytetrafluoroethylene wire mesh corrugated structured packing. The polytetrafluoroethylene silk screen corrugated structured packing is formed by combining one or more layers of polytetrafluoroethylene silk screen corrugated sheets macroscopically, the silk screen is of a metal solid structure, the aperture of a mesh surrounded by the silk screen is 2-60 meshes (preferably 10-30 meshes), and the area percentage of the mesh is 50% -95%. The novel structured packing can keep the excellent corrosion resistance of the polytetrafluoroethylene material, 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 polytetrafluoroethylene structured packing is basically solid plate corrugation, a high-strength and high-surface-area wire mesh structure cannot be prepared, the preparation process has poor controllability, high cost and low efficiency, and the invention develops the polytetrafluoroethylene wire mesh corrugated structured packing with high strength, high specific surface, controllable structure, high efficiency and corrosion resistance, and the advantages and the beneficial effects of the invention are as follows:

1. the structured packing prepared by the high-strength polytetrafluoroethylene 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 packing material is a polytetrafluoroethylene material, the high chemical stability of strong acid and strong alkali corrosion resistance ensures the long service life of the packing, the maintenance period of the 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 consumption of the existing polytetrafluoroethylene solid plate corrugated packing can be greatly reduced, the tower height is reduced, and the equipment investment cost is reduced.

3. The novel high-strength polytetrafluoroethylene silk screen corrugated structured packing is characterized in that a metal silk screen is used as a template, a corrugated plate shape suitable for the packing structure requirement is obtained through slurry impregnation, and then a packing disc is assembled; or the wire mesh is directly welded and processed into the finished wire mesh packing tray, and the corrugated plate shape suitable for the packing structure requirement is obtained through slurry impregnation and is prepared by high-temperature heating.

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 (c) are the screen hole type structure-conventional polygon structure of the high-strength two-dimensional polytetrafluoroethylene screen material of the invention: FIG. 2(a) is a trilateral; FIG. 2(b) is a quadrangle; FIG. 2(c) is a regular hexagon; wherein a and b represent the respective feature sizes, and α represents the angle between the feature sizes.

Fig. 3(a) -fig. 3(b) are the screen hole type structure-special (variant) polygon structure of the high-strength two-dimensional polytetrafluoroethylene screen material of the invention: FIG. 3(a) is a hexagon; FIG. 3(b) 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.

FIGS. 4(a) to 4(b) show the types of the corrugated shapes S of the corrugated sheets in the high-strength two-dimensional polytetrafluoroethylene screen material according to the invention. Wherein, fig. 4(a) is a triangular corrugation, H represents a peak height, α represents a corrugation angle, and l represents a wave distance; fig. 4(b) is a triangle with rounded vertices, H represents the peak height, α represents the corrugation angle, and l represents the wave distance.

FIGS. 5(a) -5 (b) show the polytetrafluoroethylene wire mesh corrugated structured packing (wire mesh with 30 mesh diameter, made of polytetrafluoroethylene with metal core material) of the present invention. Wherein, fig. 5(a) is a real object diagram of a 30-mesh wire mesh corrugated plate; FIG. 5(b) is a block diagram of a 30 mesh wire mesh corrugated packing.

FIGS. 6(a) -6 (b) are the polytetrafluoroethylene wire mesh corrugated structured packing (the wire mesh has a 10-mesh aperture and is made of polytetrafluoroethylene with a metal core material). Wherein, fig. 6(a) is a 10-mesh silk screen corrugated plate object diagram; FIG. 6(b) is a block diagram of a 10 mesh wire mesh corrugated packing.

Fig. 7 is a schematic illustration of a phi 3000mm packing cup.

Detailed Description

The present invention will be described in further detail with reference to specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the specific implementation process, polytetrafluoroethylene wire mesh corrugated plates with 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. After the polytetrafluoroethylene slurry is coated on the metal wire mesh, a wire mesh corrugated plate precursor is obtained, then the precursor is coated to the required surface density, and then the precursor is assembled into a packing disc (block), and finally the packing disc (block) is heated at high temperature to form the polytetrafluoroethylene wire mesh corrugated regular packing.

As shown in fig. 4(a) -4 (b), the corrugated plate of the novel corrosion-resistant high-strength polytetrafluoroethylene wire mesh corrugated structured packing provided by the invention is triangular or smooth-topped triangular, and has the functions of increasing resistance to mechanical load and reducing stress concentration at the tops of triangular corrugations; 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 adjacent wave peak top points.

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 (c), the screen hole type structure of the high-strength two-dimensional polytetrafluoroethylene screen material of the invention, i.e. the conventional polygonal structure: FIG. 2(a) is a trilateral shape, which functions to achieve triangular mesh and its close packing; FIG. 2(b) is a quadrilateral shape, the purpose of which is to achieve rectangular meshes and their close packing; fig. 2(c) is a regular hexagon, which has the effect of achieving a regular hexagonal mesh and its close packing.

As shown in fig. 3(a) -3 (b), the screen hole type structure of the high-strength two-dimensional polytetrafluoroethylene screen material of the invention, a special (variant) polygonal structure: FIG. 3(a) is a hexagon, which functions to realize a regular hexagonal mesh; the multi-blade propeller is polygonal, and has the function of realizing mesh with different shapes and close packing; fig. 3(b) is a regular triangle + a regular hexagon, and the function of the mesh is to realize the combination of regular triangle meshes and regular hexagon meshes.

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 polytetrafluoroethylene wire mesh corrugated structured packing is as follows:

firstly, coating slurry on a metal wire mesh in an airless spraying or dip-coating mode, and then preparing a polytetrafluoroethylene wire mesh corrugated plate precursor according to corresponding geometrical characteristics. Then, the same slurry is used as an adhesive, the screen corrugated plate precursors are stacked in parallel to form a filler disc structure, and the filler disc structure is bonded according to the requirements of the regular filler structure and then heated at high temperature for forming, so that the high-strength polytetrafluoroethylene screen corrugated regular filler is obtained. In the preparation process of the polytetrafluoroethylene silk screen corrugated structured packing, the precursor of the polytetrafluoroethylene silk screen corrugated plate is connected into a packing tray at one time, the diameter of the packing tray is 100mm, the tray height is 100mm, the corrugated plate is firmly combined, the installation is easy, and the structure is stable. The apparent compressive strength (force that can be withstood per unit macroscopic area) of the packing cup is 150 MPa.

In this embodiment, the preparation process of the high-strength polytetrafluoroethylene wire mesh corrugated plate precursor is as follows:

and (3) drying and curing the slurry coated on one or more layers of the wire mesh filler in an airless spraying or dip-coating mode at 150 ℃ to obtain the precursor of the polytetrafluoroethylene wire mesh corrugated plate.

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 embodiment, the heating process includes:

and heating the combined and bonded packing disc in a heating furnace to 380 ℃, and then preserving the heat for 20 minutes at a heating rate of 5 ℃ per minute to generate the polytetrafluoroethylene silk screen corrugated structured packing disc.

In this embodiment, the obtained polytetrafluoroethylene wire mesh corrugated structured packing is formed by superposing and combining polytetrafluoroethylene wire mesh corrugated plates with corrugated geometric shapes, each corrugated plate is a polytetrafluoroethylene wire mesh with a three-dimensional communication network structure, and the corrugated shape of each corrugated plate is a triangle.

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 polytetrafluoroethylene wire mesh corrugated structured packing is stacked in a rectification experimental tower in a vertical crossing mode of 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 polytetrafluoroethylene silk screen corrugated regular I-type packing under different spray densities is higher than that of BX packing; experiment tests show that the pressure drop of the polytetrafluoroethylene wire mesh corrugated regular packing is obviously smaller than that of BX packing, and the reduction amplitude reaches more than 25%.

The theoretical plate number of the high-strength polytetrafluoroethylene wire mesh corrugated structured packing of the present invention is compared with that of BX wire mesh packing, and only the high-strength polytetrafluoroethylene wire mesh corrugated structured packing is listed in this embodiment, and the wire mesh aperture, the wire mesh core material, and the like are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modification, equivalent replacement, improvement, and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Example 2

The embodiment is a preparation and application of a corrugated structured packing based on a high-strength polytetrafluoroethylene mesh material, and is different from embodiment 1 in that:

preparing a final required filler disc size by using a plurality of layers of wire mesh fillers, and coating polytetrafluoroethylene slurry by adopting a dip-coating mode to prepare a polytetrafluoroethylene wire mesh corrugated plate precursor. And then heating and shaping at high temperature to obtain the high-strength polytetrafluoroethylene silk screen corrugated structured packing. In the preparation process of the polytetrafluoroethylene wire mesh corrugated structured packing, the packing disc is formed by one-step molding, the diameter of the packing disc is 100mm, the disc height is 100mm, the installation is easy, and the structure is stable. The apparent compressive strength (force that can be withstood per unit macroscopic area) of the packing cup is 150 MPa.

In this embodiment, the sintering process includes:

heating the polytetrafluoroethylene packing disc in a heating furnace to 380 ℃, then preserving the heat for 20 minutes at the heating rate of 5 ℃ per minute, and preparing the polytetrafluoroethylene wire mesh corrugated structured packing disc.

In this embodiment, the obtained polytetrafluoroethylene silk screen corrugated structured packing is tetrafluoroethylene silk screen corrugated plate structured packing with a corrugated geometric shape, the corrugated plate is a tetrafluoroethylene silk screen with a three-dimensional connected network structure, and the corrugated shape of the corrugated plate is a triangle.

the high-strength tetrafluoroethylene silk screen corrugated structured packing obtained in the embodiment is vertically crossed with the upper and lower layer unit plates

The method is stacked and loaded in a rectification experimental tower, an alcohol-water binary system is utilized for experimental research, the experimental process is total reflux operation, and comparison is carried out with the BX regular 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 polytetrafluoroethylene 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%.

In this embodiment, only the high strength silicon carbide mesh corrugated structured packing is listed, and the mesh aperture, the organic mesh material, the teflon 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 embodiment is a preparation and application of a corrugated structured packing based on a high-strength alumina polytetrafluoroethylene mesh material, and is different from embodiment 2 in that:

the polytetrafluoroethylene wire mesh corrugated 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 polytetrafluoroethylene 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 is 150 MPa.

Example 4

This example is an evaluation of the application properties of corrugated structured packing based on high strength polytetrafluoroethylene mesh material. In particular to the corrosion resistance research of the high-strength polytetrafluoroethylene wire mesh 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, and three kinds of materials with different concentrations are prepared

After the polytetrafluoroethylene screen corrugated regular packing and the BX packing (316L) are soaked in three solutions with different concentrations for three weeks, the mass change rates before and after the hydrochloric acid (respectively 5 wt%, 10 wt% and 20 wt%) are measured, which shows that the polytetrafluoroethylene screen corrugated regular packing is not corroded, the BX packing (316L) has obvious weight loss, and partial areas are corroded and even holes appear.

(2) The corrosion resistance of the material is researched and compared by adopting H2 SO 4 as a medium, three sulfuric acids (5 wt%, 20 wt% and 35 wt% respectively) with different concentrations are prepared, and after the polytetrafluoroethylene wire mesh corrugated regular packing and the BX packing (316L) are soaked in three solutions with different concentrations for three weeks, the mass change rate before and after measurement shows that the three wire mesh corrugated regular packings are not corroded, and the BX packing (316L) has obvious weight loss and holes.

(3) The HNO 3 is adopted as a medium to research and compare the corrosion resistance of the material, three kinds of nitric acid with different concentrations (5 wt%, 10 wt% and 20 wt% respectively) are prepared, and after the polytetrafluoroethylene 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 rate before and after measurement shows that the three kinds of polytetrafluoroethylene wire mesh corrugated structured packing are not corroded, the BX packing (316L) has obvious weight loss, 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 polytetrafluoroethylene 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 polytetrafluoroethylene 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 polytetrafluoroethylene wire mesh corrugated structured packing (wire mesh aperture of 30 mesh and 10 mesh), the corrugated shape and structure are rich; 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. 7, 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 corrugated plate is formed by combining high-strength polytetrafluoroethylene wire mesh corrugated plates with metal inner cores and corrugated geometric shapes, the high-strength polytetrafluoroethylene wire mesh regular corrugated plates well keep the network characteristics of a metal wire mesh, and have the characteristics of large specific surface area, thin wall, high strength, controllable structure and high chemical stability.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The present invention has been described in detail with reference to the examples, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims

1. A high-strength polytetrafluoroethylene silk screen corrugated structured packing is characterized in that the high-strength polytetrafluoroethylene silk screen corrugated structured packing is basically composed of a corrugated polytetrafluoroethylene silk screen material, the polytetrafluoroethylene silk screen material contains a metal core material composed of single-stranded metal wires or multi-stranded metal wires, and the metal core material is coated with a polytetrafluoroethylene material; one or more layers of corrugated polytetrafluoroethylene wire mesh materials are superposed to form polytetrafluoroethylene wire mesh corrugated plates, the superposed polytetrafluoroethylene wire mesh corrugated plates are vertically arranged, and planes where wave crests or wave troughs of the polytetrafluoroethylene wire mesh corrugated plates are located are parallel to each other; the direction of a wave crest line or a wave trough line of the corrugation has an inclination angle of between 15 and 85 degrees with the vertical direction, the inclination angles of adjacent polytetrafluoroethylene silk screen corrugated plates are the same, and the directions are opposite; the metal core material, the mesh structure and the mesh hole type structure are the same or different.

2. The high-strength polytetrafluoroethylene wire mesh corrugated structured packing as recited in claim 1, wherein the wire mesh of the polytetrafluoroethylene wire mesh corrugated plate has an inner core made of metal, the outer layer of the inner core is coated with the high-strength polytetrafluoroethylene, the wire mesh pattern of the polytetrafluoroethylene wire mesh corrugated plate is one or more of a circular, elliptical, regular polygon, modified polygon, graded polygon, chiral or anti-chiral structure, and the corrugation of the polytetrafluoroethylene wire mesh corrugated plate is one or more 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 polytetrafluoroethylene wire mesh corrugated structured packing as claimed in claim 2, wherein the wire mesh aperture of the polytetrafluoroethylene wire mesh corrugated plate is 2-60 mesh, and the wire mesh aperture area ratio is 50-95%.

4. The high-strength polytetrafluoroethylene wire mesh corrugated structured packing as recited in claim 2, wherein the wire mesh of the polytetrafluoroethylene wire mesh corrugated plate contains a metal core material of one or more of aluminum-based alloy, stainless steel, iron-based, nickel-based, and copper-based metals.

5. The high strength polytetrafluoroethylene wire mesh corrugated structured packing of claim 2, wherein the wire mesh of the polytetrafluoroethylene wire mesh corrugated sheet contains a metal core of single or multiple wires.

6. The high-strength polytetrafluoroethylene wire mesh corrugated structured packing as claimed in claim 1, wherein the polytetrafluoroethylene wire mesh corrugated plate has one or more of a triangular shape, a vertex smooth triangular shape, a sine wave shape and a smooth wave shape, the corrugation size and structure are adjustable, the peak height H is 2-50 mm, and the corrugation angle α is 30-150 °; 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.

7. A method for preparing the high-strength polytetrafluoroethylene wire mesh corrugated structured packing according to any one of claims 1 to 6, wherein the method comprises the following steps:

step one, preparing a wire mesh corrugated plate:

step 101, a single-layer metal wire mesh corrugated plate or a plurality of layers of metal wire mesh corrugated plates are selected and welded to form a finished product of metal wire mesh regular packing as a framework core material;

step 102, uniformly coating polytetrafluoroethylene slurry on a metal wire mesh by adopting a gas spraying, airless spraying or slurry dipping process, and then putting the metal wire mesh in a heater at 130-180 ℃ for heating and curing molding to obtain the wire mesh corrugated structured packing of the metal inner core coated with the polytetrafluoroethylene slurry;

step 103, recoating: continuously and repeatedly coating the polytetrafluoroethylene slurry-coated metal inner core wire mesh corrugated structured packing obtained in the step 1.2 with slurry 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 polytetrafluoroethylene wire mesh corrugated precursor;

step 2, superposing and combining more than two polytetrafluoroethylene wire mesh corrugated plates to prepare a filler disc unit module:

step 201, using polytetrafluoroethylene slurry same as that in the step one as an adhesive, coating polytetrafluoroethylene slurry on part or all of corrugation crest lines of a precursor of a polytetrafluoroethylene wire mesh corrugated plate, superposing and combining the polytetrafluoroethylene slurry in parallel, and bonding the polytetrafluoroethylene slurry of the same kind to form a blank of a filler disc unit module;

step 202, preprocessing a blank of the packing pan unit module to obtain a heating precursor of the packing pan unit module;

and 203, processing and molding the heating precursor of the packing pan unit module into the shape and the size of the required packing pan module, and heating to 350-400 ℃ to obtain the polytetrafluoroethylene silk screen corrugated structured packing product.

And step three, preparing a filler disc unit module precursor by polytetrafluoroethylene wire mesh corrugations formed by taking the multilayer metal wire mesh structured filler as a framework core material, and heating the precursor to 350-400 ℃ to obtain a polytetrafluoroethylene wire mesh corrugated structured filler product.

And step four, processing and molding the polytetrafluoroethylene wire mesh corrugated precursor obtained in the step one into a required filler disc module shape and size, heating to 350-400 ℃ to form polytetrafluoroethylene wire mesh corrugated plates, superposing and combining two layers of wire mesh corrugated plates in parallel, enabling the directions of adjacent corrugated plates to be opposite, welding two layers of wave peak contact points together by using polytetrafluoroethylene rods at high temperature, integrating the two layers of wire mesh corrugated plates by welding, and then welding one layer after another to reach the required number of layers to prepare the filler disc unit module.

8. The method according to claim 7, wherein in step 101, the metal screen used as the template material is one or more of aluminum-based alloy, stainless steel, iron-based, nickel-based, and copper-based metal; the meshes of the metal wire mesh consist of single-strand or multi-strand metal wires, and the meshes of the metal wire mesh are in one or more than two of circular, oval, conventional polygon, variant polygon, graded polygon, chiral or anti-chiral structures, preferably one or more than two of circular, triangular, quadrilateral and hexagonal structures.

9. The method for preparing the high-strength polytetrafluoroethylene wire mesh corrugated structured packing according to claim 7, wherein in the step 203, the steps three and four, different heating methods and processes are adopted in the heating process according to different polytetrafluoroethylene slurry types; including heating temperature, heating time, temperature rise and temperature drop curves, etc.

10. Use of a high strength polytetrafluoroethylene wire mesh corrugated structured packing according to any one of claims 1 to 6,

the polytetrafluoroethylene silk screen 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.

11. The use of the high strength polytetrafluoroethylene wire mesh corrugated structured packing as recited in claim 10, wherein the polytetrafluoroethylene wire mesh corrugated structured packing is used in the separation of various strong corrosion systems, and is used for the separation and purification of corrosion systems containing sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid or cyclopentanoic acid, depending on the material and thickness of the slurry.