A wire mesh demister for a POE flash tank

Abstract

The application discloses a wire mesh demister for a POE flash tank and relates to the technical field of POE production. The wire mesh demister for the POE flash tank comprises a wire mesh, the surface of the wire mesh is provided with a composite coating, and the composite coating is formed by sintering composite nanoparticles on the surface of the wire mesh; the composite nanoparticles comprise transition metal phosphide and silicon carbide, and the mass ratio of the transition metal phosphide to the silicon carbide is (20-40):1. The application can effectively capture POE glue liquid and achieve the best effect of gas-liquid separation.

Description

Technical Field

[0001] This invention relates to the technical field of POE production, and more particularly to a wire mesh demister for POE flash tanks. Background Technology

[0002] The POE flash evaporator is a core piece of equipment in POE production. This process allows the polymer solution concentration to reach over 95 wt%, so removing solvents and volatiles is crucial, significantly impacting subsequent processes and cost reduction. Current processes typically install a standard wire mesh demister at the top gas phase outlet of the POE flash evaporator. This demister is made of non-metallic (such as PTFE) filaments (0.1-0.28 mm in diameter) woven into a multi-layered corrugated mesh to increase the specific surface area and contact probability. Through the synergistic action of multiple physical mechanisms, it separates the POE resin mist entrained in the gas.

[0003] The main substances at the top gas phase outlet of the POE flash evaporator include ethylene, hexane, and trace amounts of POE adhesive. However, due to their high viscosity and high surface tension (e.g., latex surface tension ranges from 20-40 mN / m), POE adhesive droplets are difficult to settle in the gas phase. Furthermore, the high viscosity, low volatility, and tendency to form stable foams characteristic of POE adhesive droplets make them difficult to effectively capture with conventional demisters. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wire mesh demister for POE flash tanks, which can effectively capture POE liquid and achieve the best gas-liquid separation effect.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a wire mesh demister for a POE flash tank, the wire mesh demister comprising a wire mesh, the surface of which is provided with a composite coating, the composite coating being formed by sintering composite nanoparticles on the surface of the wire mesh; The composite nanoparticles comprise transition metal phosphides and silicon carbide, wherein the mass ratio of the transition metal phosphides to silicon carbide is (20-40):1.

[0006] Preferably, the mass ratio of the transition metal phosphide to silicon carbide is (25-30):1, for example, it can be 25:1, 26:1, 27:1, 28:1, 29:1, 30:1 or any two of these values.

[0007] Preferably, the average particle size of the silicon carbide is 10-50 μm, for example, it can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or any two of these values.

[0008] Preferably, the specific surface area of ​​the silicon carbide is 1000-1200 m². 2 / g, for example, could be 1000m 2 / g, 1050m 2 / g、1100m 2 / g、1150m 2 / g、1200m 2 / g or a range consisting of any two of its values.

[0009] This invention improves the adsorption of POE adhesive by controlling the particle size and specific surface area of ​​silicon carbide, thereby enabling better separation of POE adhesive from gas.

[0010] Preferably, the transition metal phosphide includes at least one of FeCoNiP, CoNiP3, and CoNi3P.

[0011] Preferably, the thickness of the composite coating is 50-100 nm, for example, it can be a range of 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm or any two of these values.

[0012] Preferably, the average particle size of the composite nanoparticles is 30-50 nm, for example, it can be a range of 30 nm, 35 nm, 40 nm, 45 nm, 50 nm or any two of these values.

[0013] Preferably, the specific surface area of ​​the composite nanoparticles is 1000-1500 m². 2 / g, for example, could be 1000m 2 / g、1100m 2 / g、1200m 2 / g、1300m 2 / g, 1400m 2 / g, 1500m 2 / g or a range consisting of any two of its values.

[0014] Preferably, the porosity of the composite nanoparticles is 50-60%, for example, it can be a range of 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, or any two of these values.

[0015] Preferably, the mesh count of the wire mesh is 15-25.

[0016] If the mesh count of the wire mesh is too large (the aperture is too small), it can easily cause clogging. If the mesh count is too small (the aperture is too large), it can easily cause adhesive droplets to be entrained and enter downstream equipment, leading to equipment failure. Therefore, this invention improves the efficiency of gas-liquid separation by controlling the mesh count of the wire mesh.

[0017] Preferably, the method for preparing the composite coating includes the following steps: sintering composite nanoparticles onto the surface of a wire mesh in a microwave electromagnetic field to obtain the composite coating.

[0018] Preferably, the sintering temperature is 200-220℃ and the sintering time is 10-20 min.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The POE flash tank wire mesh demister of the present invention has a composite coating composed of transition metal phosphide and silicon carbide on its surface. When ethylene, hexane and trace amounts of POE adhesive rise to the wire mesh demister, the trace amounts of POE adhesive diffuse to the composite coating on the wire mesh surface through Brownian motion, are adsorbed and aggregated to quickly form large droplets. When the gravity of the droplets exceeds the resultant force of the gas rise force and the liquid surface tension, they fall from the wire mesh hinge point, thereby achieving the separation of POE adhesive from ethylene and hexane gases. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the POE flash tank described in this invention.

[0021] Figure 2 This is a top view of the wire mesh demister described in this invention.

[0022] Among them, 1 is the support block; 2 is the fastener; 3 is the wire mesh; and 4 is the flash tank. Detailed Implementation

[0023] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the scope of protection and implementation of the present invention are not limited thereto.

[0024] Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0025] Example 1 This embodiment discloses a wire mesh demister for a POE flash tank, the wire mesh demister comprising a wire mesh 3, such as... Figure 2 As shown, the center of the wire mesh 3 is slightly raised, and the wire mesh 3 is parabolic in shape, radiating regularly from the center line. This design can effectively capture the POE adhesive in the top gas phase; the distance between the highest point of the protrusion and the bottom of the wire mesh 3 is 50 mm. The mesh count of the wire mesh is 20 mesh.

[0026] The surface of the wire mesh 3 is provided with a composite coating, which is formed by sintering composite nanoparticles on the surface of the wire mesh in a microwave electromagnetic field at a temperature of 220°C for 20 minutes. The thickness of the composite coating is 80 nm.

[0027] The composite nanoparticles comprise FeCoNiP and silicon carbide, with a mass ratio of FeCoNiP to silicon carbide of 30:1. The average particle size of the composite nanoparticles is 40 nm, and the specific surface area is 1000 m². 2 / g, with a porosity of 55%.

[0028] The silicon carbide has an average particle size of 30 μm and a specific surface area of ​​1200 m². 2 / g.

[0029] This embodiment also discloses a POE flash evaporator, such as Figure 1 As shown, the device includes a flash tank 4 and a wire mesh demister. Two symmetrically arranged support blocks 1 are fixed to the inner wall of the flash tank 4. The wire mesh demister also includes fasteners 2 for fixing the wire mesh. The fasteners 2 include bolts, which are installed on the support blocks 1. The wire mesh 3 is fixed to the top of the flash tank 4 by the bolts.

[0030] When ethylene, hexane, and trace amounts of POE adhesive rise to the wire mesh demister, the trace amounts of POE adhesive diffuse to the composite coating on the wire mesh surface through Brownian motion, where they are adsorbed and aggregate to quickly form large droplets. When the weight of the droplets exceeds the combined force of the gas uplift force and the liquid surface tension, they fall from the wire mesh hinge point, thus achieving the separation of POE adhesive from ethylene and hexane gases.

[0031] Example 2 A wire mesh demister for a POE flash tank, differing from Example 1 in that the mass ratio of FeCoNiP to silicon carbide is 20:1.

[0032] Example 3 A wire mesh demister for a POE flash tank, differing from Example 1 in that the mass ratio of FeCoNiP to silicon carbide is 40:1.

[0033] Example 4 A wire mesh demister for a POE flash tank, differing from Example 1 in that the thickness of the composite coating is 50 nm.

[0034] Example 5 A wire mesh demister for a POE flash tank, differing from Example 1 in that the thickness of the composite coating is 100 nm.

[0035] Example 6 A wire mesh demister for a POE flash tank, differing from Embodiment 1 in that the wire mesh has a mesh count of 15.

[0036] Example 7 A wire mesh demister for a POE flash tank, differing from Embodiment 1 in that the wire mesh has a mesh count of 25.

[0037] Comparative Example 1 A wire mesh demister for a POE flash tank, differing from Example 1 in that the composite nanoparticles consist only of FeCoNiP.

[0038] Comparative Example 2 A wire mesh demister for a POE flash tank, differing from Example 1 in that the composite nanoparticles consist only of silicon carbide.

[0039] Comparative Example 3 A wire mesh demister for a POE flash tank, differing from Example 1 in that the mass ratio of FeCoNiP to silicon carbide is 10:1.

[0040] Comparative Example 4 A wire mesh demister for a POE flash tank, differing from Example 1 in that the mass ratio of FeCoNiP to silicon carbide is 50:1.

[0041] Comparative Example 5 A wire mesh demister for a POE flash tank, differing from Example 1 in that it uses an equal mass of activated carbon instead of silicon carbide.

[0042] Comparative Example 6 A wire mesh demister for a POE flash tank, differing from Example 1 in that an equal mass of phosphorus-rich phosphide CoNiP3 is used instead of FeCoNiP.

[0043] The residual adsorbed weight of the POE adhesive solution by the wire mesh demisters in the above embodiments and comparative examples was measured respectively (because most of the adhesive solution rapidly aggregates into large droplets after adsorption and returns to the liquid phase in the flash tank under gravity). The measurement method was gravimetric method (high-precision detection). The principle is to directly measure the mass change of the POE adhesive solution sample during the wire mesh adsorption process in different embodiments and comparative examples using a high-precision balance (accuracy 0.1 mg). The steps are as follows: 1. A flash tank with continuously stable operating reaction conditions at equilibrium was used as the system evaluation carrier.

[0044] 2. The sampling time is one hour.

[0045] 3. Ensure that the ambient temperature and humidity are consistent at each sampling point.

[0046] 4. Before each experiment, the screens of the examples and comparative examples were physicochemically cleaned, weighed using a microbalance sample pan, and the initial data were recorded to ensure data consistency.

[0047] 5. When the sampling time arrives, remove the wire mesh and promptly record the weight.

[0048] The test results are shown in Table 1.

[0049] Table 1 Comparing Comparative Examples 1-2 and 5-6 with Example 1, it can be seen that no silicon carbide was added in Comparative Example 1, no transition metal phosphides were added in Comparative Example 2, and the adsorption weight of POE adhesive in Comparative Examples 1-2 was lower than that in Example 1. In Comparative Example 5, an equal mass of activated carbon was used to replace silicon carbide, and in Comparative Example 6, other types of phosphides were used to replace transition metal phosphides. The adsorption weight of POE adhesive in Comparative Examples 5-6 was lower than that in Example 1. This indicates that only by using a combination of transition metal phosphides and silicon carbide can the composite nanoparticles of the present invention enhance the ability of the composite coating to capture POE adhesive, thereby improving the separation effect of POE adhesive from gas.

[0050] Comparing Comparative Examples 3-4 with Example 1, it can be seen that if the mass ratio of transition metal phosphide to silicon carbide is too small or too large, it will have a certain impact on the adsorption weight of POE adhesive. This indicates that by controlling the mass ratio of transition metal phosphide to silicon carbide within the range defined by the present invention, it is beneficial to improve the ability of the composite coating to capture POE adhesive, thereby achieving the best gas-liquid separation effect.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A wire mesh demister for a POE flash tank, characterized in that, The wire mesh demister includes a wire mesh, the surface of which is provided with a composite coating, the composite coating being formed by sintering composite nanoparticles on the surface of the wire mesh. The composite nanoparticles comprise transition metal phosphides and silicon carbide, wherein the mass ratio of the transition metal phosphides to silicon carbide is (20-40):

1.

2. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The mass ratio of the transition metal phosphide to silicon carbide is (25-30):

1.

3. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The silicon carbide has an average particle size of 10-50 μm and a specific surface area of ​​1000-1200 m². 2 / g.

4. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The transition metal phosphide includes at least one of FeCoNiP, CoNiP3, and CoNi3P.

5. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The thickness of the composite coating is 50-100 nm.

6. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The composite nanoparticles have an average particle size of 30-50 nm and a specific surface area of ​​1000-1500 m². 2 / g.

7. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The porosity of the composite nanoparticles is 50-60%.

8. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The mesh count of the wire mesh is 15-25.

9. The wire mesh demister for a POE flash tank as described in claim 1, characterized in that, The method for preparing the composite coating includes the following steps: sintering composite nanoparticles onto the surface of a wire mesh in a microwave electromagnetic field to obtain the composite coating.

10. The wire mesh demister for a POE flash tank as described in claim 9, characterized in that, The sintering temperature is 200-220℃, and the sintering time is 10-20 min.

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