Flexible floating roof assembly and carbon dioxide isolation device for a desalination tank

Abstract

The present application relates to the technical field of high polymer material and the technical field of interface chemistry, and in particular to a flexible floating roof assembly for a desalination water tank and a carbon dioxide isolation device. The flexible floating roof assembly comprises: an annular elastomer and a low-density polyolefin sheet nested in the annular elastomer; wherein the low-density polyolefin sheet comprises: a low-density polyolefin base material and hydrophilic side groups and oleophilic side groups grafted on the surface of the low-density polyolefin base material; and the surface of the low-density polyolefin sheet has a plurality of special-shaped structures, the average size of the special-shaped structures is not less than 100 microns, and the height is not greater than 20 microns; the surface grafting rate of the hydrophilic side groups is 10-50%, and the surface grafting rate of the oleophilic side groups is 10-50%. The ability of the flexible floating roof assembly to block carbon dioxide for a desalination water tank is greater than 95%, and the conductivity of the desalination water is less than 0.2 us / cm.

Description

Technical Field

[0001] This invention relates to the fields of polymer materials technology and interface chemistry technology, specifically to a flexible floating roof assembly and a carbon dioxide isolation device for demineralized water tanks. Background Technology

[0002] Demineralized water tanks are essential equipment in the boiler feedwater systems of thermal power plants. With the increasing installed capacity of power plants, the requirements for water quality are also becoming more stringent. Because most existing demineralized water tanks in power plants lack effective sealing, the demineralized water is easily contaminated by carbon dioxide, oxygen, and dust in the air during storage, affecting the water quality and leading to scaling and corrosion throughout the system. Therefore, power plants need to install floating roofs on existing demineralized water tanks to ensure water quality. However, the existing demineralized water tank walls are often connected by overlapping and staggered welding of steel plates, creating a stepped effect where the tank's inner diameter gradually decreases from bottom to top. This means that if the installed flexible floating roof has the same cross-sectional area as the lower part of the tank, it may jam and roll over at high water levels, potentially even causing tipping. Conversely, if the area of ​​the installed floating roof is equal to the cross-sectional area of ​​the upper part of the tank, it cannot form an effective seal, failing to achieve the desired effect. CN216710315U discloses a combined flexible floating roof for demineralized water tanks in thermal power generating units. The flexible floating roof includes a central flexible floating roof inside the tank, with a certain gap between the edge of the flexible floating roof and the inner wall of the demineralized water tank filled with flexible floating balls. However, the floating balls cannot completely block carbon dioxide, and when the demineralized water level in the tank is low, there is a risk that the floating balls will be pumped away, affecting the operation of the device. To overcome the shortcomings of the existing technology, it is necessary to continue developing new materials for flexible floating roofs of demineralized water tanks that can suppress carbon dioxide. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of poor carbon dioxide blocking effect, poor durability, and high cost of existing demineralized water tank floating roof materials. This invention provides a flexible floating roof assembly and a carbon dioxide isolation device for demineralized water tanks. The flexible floating roof assembly can isolate water and oil and can block carbon dioxide.

[0004] To achieve the above objectives, a first aspect of the present invention provides a flexible floating roof assembly for a demineralized water tank, the flexible floating roof assembly comprising: an annular elastomer and a low-density polyolefin sheet nested within the annular elastomer;

[0005] The low-density polyolefin sheet comprises: a low-density polyolefin substrate and hydrophilic and oleophilic side groups grafted onto the surface of the low-density polyolefin substrate; and the surface of the low-density polyolefin sheet has multiple irregular structures, the average size of the irregular structures being not less than 100 μm and the height not greater than 20 μm; the surface grafting rate of the hydrophilic side groups is 10-50%, and the surface grafting rate of the oleophilic side groups is 10-50%.

[0006] A second aspect of the present invention provides a carbon dioxide isolation device, wherein the flexible floating roof assembly described in the present invention is disposed inside the device.

[0007] Since CO2 can penetrate into small pores larger than 0.01 μm, existing technologies cannot effectively block carbon dioxide from surfaces with micro- and nano-capillary structures.

[0008] The flexible floating roof assembly described in this invention has the following advantages through the above technical solution:

[0009] (1) The flexible floating roof assembly of the present invention is assembled from low-density polyolefin sheets containing hydrophilic and oleophilic surfaces. Under the premise of ensuring that the mechanical properties of the material surface are not affected, the hydrophilic and oleophilic groups grafted on the surface of the low-density polyolefin substrate and the roughness of the irregular structure effectively improve the hydrophilicity and oleophilicity of the hydrophilic surface and stabilize the performance. This effectively improves the material's efficiency in reducing water and oil evaporation and stabilizes the performance. The irregular structure is the outer surface of closed pores, and the closed pore structure of the outer surface can completely block carbon dioxide.

[0010] (2) In the flexible floating roof assembly provided by the present invention, the low-density polyolefin sheet can be completely wetted by water and oil. Therefore, the surface of the sheet is completely attached to the demineralized water surface and there is no vapor pressure. In this way, the sheet can significantly inhibit the permeation of carbon dioxide. Under special working conditions (such as sudden pressure changes in the brine tank and large swing amplitude of the floating roof material), the floating roof can still isolate water, oil and carbon dioxide from contact, so that the demineralized water can maintain a stable conductivity. The flexible floating roof assembly has a carbon dioxide blocking capacity of more than 95% for the demineralized water tank and a conductivity of less than 0.2 μs / cm for the demineralized water.

[0011] (3) The flexible floating roof component provided by the present invention has a simple structure, is easy to install, and does not require frequent replacement of parts. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a flexible floating roof component structure made using a circular demineralized water tank as a template, provided by the present invention.

[0013] Figure 2 This is a SEM image of the surface of the low-density polyolefin sheet prepared in Example 1.

[0014] Explanation of reference numerals in the attached figures

[0015] 1—Low-density polyolefin sheet; 2—Supporting skeleton; 3—Annular elastomer; 4—Demineralized water tank body. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] In this invention, irregular structure refers to the part of the polyolefin surface that protrudes (exceeds the surface of the polyolefin).

[0018] In this invention, the average size of the irregular structure refers to the distance between two points in the ring-shaped irregular structure where the distance is at its maximum. The testing method includes: taking a surface image of the polyolefin material using a scanning electron microscope and measuring the size using the microscope's scale; (e.g.) Figure 2 As shown, the length of the line segment represents the size of the annular irregular structure, and the average size of the irregular structure refers to the average size of all annular irregular structures within the same SEM image.

[0019] A more preferred testing method is to calculate the average size of the irregular structure from multiple SEM images, and then take the average value as the average size of the irregular structure. For example, 2-10 SEM images, or 5 SEM images.

[0020] The first aspect of the present invention provides a flexible floating roof assembly for a demineralized water tank, the flexible floating roof assembly comprising: an annular elastomer and a low-density polyolefin sheet nested within the annular elastomer;

[0021] The low-density polyolefin sheet comprises: a low-density polyolefin substrate and hydrophilic and oleophilic side groups grafted onto the surface of the low-density polyolefin substrate; and the surface of the low-density polyolefin sheet has multiple irregular structures, the average size of the irregular structures being not less than 100 μm and the height not greater than 20 μm; the surface grafting rate of the hydrophilic side groups is 10-50%, and the surface grafting rate of the oleophilic side groups is 10-50%.

[0022] According to a preferred embodiment of the present invention, the average size of the irregular structure is no greater than 5 mm.

[0023] According to a preferred embodiment of the present invention, the height of the irregular structure is not less than 0.5 μm.

[0024] According to a preferred embodiment of the present invention, the water contact angle of the surface of the low-density polyolefin sheet is <30°, preferably 0-20°, and more preferably 0°.

[0025] According to a preferred embodiment of the present invention, the white oil contact angle on the surface of the low-density polyolefin sheet is <30°, preferably 0-20°, and more preferably 0°.

[0026] According to a preferred embodiment of the present invention, the surface of the low-density polyolefin sheet contains 5-120 irregular structures / cm 2 .

[0027] According to a preferred embodiment of the present invention, the low-density polyolefin sheet is non-porous.

[0028] According to a preferred embodiment of the present invention, the surface grafting rate of the hydrophilic side group is 20-50%.

[0029] According to a preferred embodiment of the present invention, the surface grafting rate of the oleophilic side group is 20-50%.

[0030] According to a preferred embodiment of the present invention, the density of the low-density polyolefin substrate is less than 0.2 g / cm³. 3 Preferably, the density is not greater than 0.1 g / cm³. 3 .

[0031] According to a preferred embodiment of the present invention, the low-density polyolefin sheet has a flexural strength of 0.01-0.5 MPa, preferably 0.01-0.15 MPa.

[0032] According to a preferred embodiment of the present invention, a connector is further provided between the annular elastomer and the low-density polyolefin sheet for connecting the annular elastomer and the low-density polyolefin sheet.

[0033] According to a preferred embodiment of the present invention, the annular elastomer material is selected from at least one of styrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and rubber, preferably selected from polyurethane-based thermoplastic elastomers and / or polyolefin-based thermoplastic elastomers.

[0034] In this invention, there are no special requirements for the connector, as long as the annular elastomer is in close contact with the low-density polyolefin sheet, such as an "I" shaped groove or cable tie.

[0035] In this invention, there are no special requirements for the material of the connector, as long as the annular elastomer and the low-density polyolefin sheet are in close contact. According to a preferred embodiment of the present invention, the material of the connector is a metal, an inorganic non-metal, or an organic polymer.

[0036] In this invention, there are no special requirements for the shape of the flexible floating roof assembly. The shape of the flexible floating roof assembly can be reasonably designed according to the shape of the demineralized water tank, and the shape of the annular elastomer can be reasonably set.

[0037] According to a preferred embodiment of the present invention, the flexible floating roof assembly is provided with a pressure relief hole. When an abnormal situation occurs, the pressure relief hole opens, and the flexible floating roof assembly can normally adhere to the demineralized water surface.

[0038] In this invention, the size of the low-density polyolefin sheet can be selected according to the size of the flexible floating roof assembly, or several low-density polyolefin sheets can be connected by connectors according to actual needs.

[0039] like Figure 1 As shown, the present invention provides a schematic diagram of a flexible floating roof assembly structure made using a circular demineralized water tank as a template. The flexible floating roof assembly includes an annular elastomer 3 disposed within the circular demineralized water tank body 4, a support frame 2 nested on the inner surface of the annular elastomer 3, and a low-density polyolefin sheet 1. The low-density polyolefin sheet 1 is disposed on the support frame 2; and there are no pores between the annular elastomer 3 and the low-density polyolefin sheet 1.

[0040] The support frame 2 serves as both a connector, fixing several low-density polyolefin sheets together and fixing the annular elastomer 3 to the low-density polyolefin sheet 1, and a structural support, providing strength for the flexible floating roof assembly.

[0041] In this invention, there are no particular limitations on the material of the supporting frame; lightweight and high-strength materials can meet the requirements of this invention, such as aluminum, aluminum alloys, and organic polymer materials.

[0042] According to a preferred embodiment of the present invention, the low-density polyolefin substrate is selected from thermoplastic polyolefins; thermoplastic polyolefins have the advantage of being easy to foam and mold, and thus able to prepare even lower-density polyolefin substrates.

[0043] According to a preferred embodiment of the present invention, the low-density polyolefin substrate comprises polypropylene, preferably, based on the total mass of the low-density polyolefin substrate, the content of polypropylene is not less than 50 wt%, more preferably not less than 80 wt%.

[0044] According to a preferred embodiment of the present invention, the low-density polyolefin substrate has a weight-average molecular weight of 10. 4 -106 g / mol.

[0045] According to a preferred embodiment of the present invention, the polypropylene is selected from at least one of homopolymer polypropylene, random copolymer polypropylene, and impact copolymer polypropylene.

[0046] According to a preferred embodiment of the present invention, the low-density polyolefin substrate further comprises polyethylene and / or a polyolefin elastomer.

[0047] According to a preferred embodiment of the present invention, based on the total mass of the low-density polyolefin substrate, the polypropylene content is 50-100 wt%; the polyethylene content is 0-50 wt%; and the polyolefin elastomer content is 0-50 wt%. Polypropylene contributes to the stability of the rigidity of the low-density polyolefin material, while the addition of polyethylene and polyolefin elastomer contributes to the improvement of the toughness of the low-density polyolefin material and the uniformity of the foam structure dimensions.

[0048] In this invention, the low-density polyolefin substrate can be at least one of polyolefin sheets, plates, and profiles.

[0049] According to a preferred embodiment of the present invention, the monomer of the hydrophilic side group is at least one selected from the following: an organic acid containing a carbon-carbon double bond, a derivative of an organic acid containing a carbon-carbon double bond, an organic acid salt containing a carbon-carbon double bond, and a vinyl-containing silane. The organic acid salt containing a carbon-carbon double bond is a product of acidification of an organic acid containing a carbon-carbon double bond and / or a product of saltification of an organic acid derivative containing a carbon-carbon double bond.

[0050] According to a preferred embodiment of the present invention, the organic acid derivative includes at least one of an anhydride of an organic acid and an ester containing an organic acid.

[0051] In this invention, the organic acid includes, but is not limited to, at least one of carboxylic acids, sulfonic acids, sulfinic acids, and thiocarboxylic acids.

[0052] According to a preferred embodiment of the present invention, the vinyl-containing silane is one or more compounds represented by formula (A):

[0053] CH2=CH2(CH2) n SiX3 type (A)

[0054] Where n is an integer from 0 to 3, and X is at least one of halogen, methoxy, ethoxy, and acetoxy.

[0055] According to a preferred embodiment of the present invention, the vinyl-containing silane is selected from at least one of vinyltrimethoxysilane and vinyltriethoxysilane.

[0056] According to a preferred embodiment of the present invention, the monomer of the hydrophilic side group is at least one selected from maleic anhydride, maleic anhydride derivatives, methacrylic acid, methacrylic acid derivatives (e.g., glycidyl methacrylate), vinyl acetate, alkenyl sulfonic acid and its derivatives (e.g., 2-acrylamido-2-methylpropanesulfonic acid, propene sulfonic acid, vinylbenzene sulfonic acid, vinyl sulfonic acid, etc.), p-styreneformic acid, p-styreneacetic acid, itaconic acid, oleic acid, arachidonic acid, and their salt-forming forms.

[0057] According to a preferred embodiment of the present invention, the monomer of the hydrophilic side group is at least one of maleic anhydride, maleic anhydride derivative, methacrylic acid, glycidyl methacrylate, and / or their salt-forming forms.

[0058] According to a preferred embodiment of the present invention, the monomer of the hydrophilic side group is maleic anhydride and / or maleic anhydride salt form.

[0059] In this invention, there is no particular limitation on the lipophilic side group. Conventional lipophilic side groups in the art can achieve the purpose of this invention. According to a preferred embodiment of this invention, the lipophilic side group is a vinyl silicone oil side group and / or a styrene side group.

[0060] According to a preferred embodiment of the present invention, the monomer of the oleophilic side group is a terminal vinyl silicone oil and / or a high vinyl silicone oil.

[0061] According to a preferred embodiment of the present invention, the monomer of the oleophilic side group is at least one of vinyl silicone oil, methyl vinyl silicone oil, vinyl hydrogen-containing silicone oil, and divinyl silicone oil.

[0062] All features of the aforementioned low-density polyolefin sheet of the present invention can achieve the purpose of the present invention. Preferably, the second aspect of the present invention provides a method for preparing the low-density polyolefin sheet of the present invention, the method comprising:

[0063] Monomers including hydrophilic side groups and lipophilic side groups are coated on the surface of a low-density polyolefin substrate and subjected to microwave irradiation at least once under pressure; the surface of the low-density polyolefin substrate has multiple irregular structures, the average size of the irregular structures is not less than 100 μm and the height is not greater than 20 μm.

[0064] Using the preparation method described in this invention, hydrophilic side-chain monomers and oleophilic side-chain monomers are grafted onto the surface of a low-density polyolefin substrate under pressure and microwave environment to form an irregular structure; the hydrophilicity and oleophilicity of the low-density polyolefin sheet surface are achieved by the hydrophilic and oleophilic groups grafted onto the surface of the low-density polyolefin substrate and the roughness of the irregular structure.

[0065] Using the preparation method of the present invention, the size and height of the irregular structure with an average size of not less than 100 μm on the surface of the low-density polyolefin substrate remain basically unchanged after grafting hydrophilic side groups and oleophilic side groups.

[0066] In this invention, there is no particular limitation on the coating method of coating monomers including hydrophilic side groups and oleophilic side groups onto the surface of low-density polyolefin substrates. Conventional coating methods in the art can be used in this invention. According to a preferred embodiment of the invention, the hydrophilic and oleophilic monomers are heated to above their melting points and mechanically sprayed onto the surface of the low-density polyolefin substrate.

[0067] According to a preferred embodiment of the present invention, hydrophilic and lipophilic side groups are grafted onto the surface of a low-density polyolefin substrate under pressure and microwave irradiation without the addition of a grafting initiator. After grafting hydrophilic and lipophilic side groups onto the surface of the low-density polyolefin substrate, the molecular weight of the low-density polyolefin substrate does not decrease, there are no residual monomers or initiator residues, and it is colorless and odorless; the hydrophilicity and lipophilicity of the surface of the low-density polyolefin substrate are significantly improved and remain stable for a long time.

[0068] In this invention, the grafting initiator refers to substances commonly used in the art to initiate polymerization reactions (including grafting reactions) of monomers, such as free radical initiators, including peroxide initiators, azo initiators, and redox initiators. Peroxide initiators can be further divided into organic peroxide initiators (e.g., dicumyl peroxide) and inorganic peroxide initiators. Specifically, it refers to various initiators used for grafting functional monomers onto polyolefins, such as dicumyl peroxide. In existing grafting methods, in order for the polyolefin to graft with the monomer, the initiator dehydrogenates the tertiary carbon of the polyolefin. However, the initiator not only dehydrogenates but also causes a large number of β-chain scission reactions in the polyolefin, meaning the reaction is too violent and uncontrollable, thus affecting the mechanical properties of the grafted polyolefin. The preparation method of this invention can graft organic acids, organic acid derivatives, vinyl silanes, vinyl silicone oils, styrene, and other side groups onto the surface of polyolefins without adding a grafting initiator. The low-density polyolefin sheet obtained by the preparation method described in this invention has no initiator residues on its surface, ensuring that the mechanical properties of the low-density polyolefin substrate surface are not affected.

[0069] In this invention, the coating amount of the hydrophilic side-group monomer on the surface of the low-density polyolefin substrate can be selected within a wide range. According to a preferred embodiment of the invention, the coating amount of the hydrophilic side-group monomer on the surface of the low-density polyolefin substrate is 0.05-10 g / cm³. 2 Preferably 0.1-5 g / cm³ 2 .

[0070] In this invention, the coating amount of the lipophilic side-group monomer on the surface of the low-density polyolefin substrate can be selected within a wide range. According to a preferred embodiment of the invention, the coating amount of the lipophilic side-group monomer on the surface of the low-density polyolefin substrate is 0.1-20 g / cm³. 2 Preferably greater than 0.1-10 g / cm³ 2 .

[0071] According to a preferred embodiment of the present invention, the pressure is greater than 0.1 MPa and less than 10 MPa, preferably 0.5-2 MPa.

[0072] In this invention, the range of microwave irradiation conditions is relatively wide. According to a preferred embodiment of this invention, the microwave irradiation conditions include: irradiation power of 1500W-100kW; irradiation time of 0.1s-100min, preferably 0.1s-7min.

[0073] In this invention, there is no particular limitation on the number of microwave irradiations. Repeated microwave irradiation can allow the foamed polyolefin sheet to repeatedly undergo the process of grafting monomer vaporization and grafting, which is beneficial to the uniformity of excess grafting monomers and the improvement of grafting rate. Preferably, the number of microwave irradiations is 1-5 times.

[0074] In this invention, the microwave irradiation can be carried out in various microwave reactors that are already available in the prior art.

[0075] According to a preferred embodiment of the present invention, the microwave irradiation is carried out in an inert gas atmosphere. Preferably, the inert gas is selected from one or more of nitrogen, helium and argon, and more preferably nitrogen.

[0076] According to a preferred embodiment of the present invention, the low-density polyolefin substrate is a foamed polyolefin sheet.

[0077] In this invention, the low-density polyolefin substrate can be polyolefin sheets obtained by existing technologies such as chemical foaming and physical foaming.

[0078] According to a preferred embodiment of the present invention, the foamed polyolefin sheet has no through holes.

[0079] According to a preferred embodiment of the present invention, the flexural strength of the foamed polyolefin sheet is 0.01-0.5 MPa, more preferably 0.01-0.15 MPa.

[0080] According to a preferred embodiment of the present invention, when the monomer of the hydrophilic side group is at least one of an organic acid, an anhydride of an organic acid, and an ester containing an organic acid, the product after microwave irradiation is subjected to a salting reaction with an alkali, and the product of the salting reaction is washed and dried.

[0081] According to a preferred embodiment of the present invention, the amount of alkali used is 0.05-20 g alkali / cm³. 2 Low-density polyolefin substrate, preferably 0.1-10 g alkali / cm³ 2 Low-density polyolefin substrate.

[0082] According to a preferred embodiment of the present invention, the alkali is dissolved in a first solvent, and the mass ratio of alkali to the first solvent is 0.1-100:100; more preferably 0.5-50:100; and even more preferably 1-30:100.

[0083] In this invention, there is no particular limitation on the type of alkali, as long as it can salt any one of the organic acid side groups, its anhydride side groups, or its ester side groups grafted on the surface of the low-density polyolefin substrate. Preferably, the alkali is selected from metal hydroxides and / or ammonia, and more preferably from metal hydroxides.

[0084] According to a preferred embodiment of the present invention, the metal hydroxide is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, lithium hydroxide, strontium hydroxide, calcium hydroxide, iron hydroxide, ferrous hydroxide, zinc hydroxide, magnesium hydroxide, cobalt hydroxide, gold hydroxide, aluminum hydroxide, copper hydroxide, beryllium hydroxide, and rare earth hydroxides, preferably one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, lithium hydroxide, strontium hydroxide, and calcium hydroxide.

[0085] In this invention, there is no particular limitation on the first solvent, as long as it can dissolve the alkali. According to a preferred embodiment of the present invention, the first solvent is selected from at least one of water and organic solvents; preferably selected from at least one of alcohol, ketone, ester and water, more preferably selected from alcohol and / or water.

[0086] According to a preferred embodiment of the present invention, the preparation method further includes: washing and drying the product obtained by microwave irradiation with a second solvent to remove unreacted monomers; preferably, further drying is performed after washing.

[0087] In this invention, the product irradiated by microwave is cleaned with a second solvent. There are no particular limitations on the cleaning method; any method sufficient to remove residual monomers can be used, and conventional cleaning methods can be employed. For example, immediately after microwave treatment, the product is immersed in a second solvent with a volume exceeding the surface of the low-density polyolefin substrate for a certain period (e.g., 5-15 minutes) at high temperature. Then, excess water is removed using a filter. Repeating this immersion and filtration process multiple times (e.g., 2-6 times) yields a clean, super-wetted surface.

[0088] In this invention, the product of the salting reaction (i.e. the product after the grafting reaction product reacts with the alkali) is preferably cleaned with a solvent to remove the alkali that has not reacted with the surface of the grafted low-density polyolefin substrate, and preferably further dried after cleaning.

[0089] In this invention, the product of the salting reaction is cleaned using a third solvent. The cleaning method is not particularly limited; any method sufficient to remove residual alkali can be used, and conventional cleaning methods can be employed. For example, immediately after the salting reaction, the surface of the grafted low-density polyolefin substrate can be immersed in a third solvent with a volume exceeding that of the substrate for a certain period (e.g., 5-15 minutes), followed by filtration to remove excess water. Repeating this immersion and filtration process multiple times (e.g., 2-6 times) yields a cleaned hydrophilic polyolefin surface.

[0090] In this invention, there are no particular limitations on the second solvent and the third solvent, as long as they can dissolve the residual monomers or remove the residual alkali on the surface of the low-density polyolefin substrate. According to a preferred embodiment of the present invention, the second solvent and the third solvent are each independently selected from at least one of water and organic solvents; preferably selected from at least one of alcohol, ketone, ester and water, more preferably selected from alcohol and / or water.

[0091] In this invention, the drying process can employ various conventional drying methods available in the prior art, including but not limited to methods such as forced-air drying and room-temperature drying. The preferred drying temperature is one that does not cause the polyolefin to melt, for example, not exceeding 160°C.

[0092] A second aspect of the present invention provides a carbon dioxide isolation device, wherein the device is internally equipped with the flexible floating roof assembly described in the present invention. The carbon dioxide isolation device equipped with the flexible floating roof assembly described in the present invention has a carbon dioxide blocking capacity of greater than 95% in a demineralized water tank, and a conductivity of less than 0.2 μS / cm for the demineralized water.

[0093] The present invention will be described in detail below through embodiments.

[0094] In the following embodiments, the water contact angle parameter was measured using an EASY DROP contact angle tester from KRUSS GmbH, Germany. The measurement range was 1-180°, the resolution was ±0.1°, and the dynamic contact angle measurement mode was used. Each time, a fixed volume of 2μL of deionized water droplet or white oil droplet was dropped onto the polyolefin surface, and the calculated initial contact angle was taken as the contact angle measurement value of the polyolefin surface. Six parallel measurements were performed, and the average value was calculated.

[0095] In the following embodiments, the surface grafting rate parameter was measured by using the energy dispersive spectroscopy (EDS) accessory of a Hitachi S4800 scanning electron microscope to measure the content of the main elements of the grafted components on the hydrophilic and oleophilic surfaces, and the grafting rate was calculated by using the molecular formula of the grafted material to determine the content of hydrophilic and oleophilic side groups.

[0096] In the following embodiments, the carbon dioxide concentration in the demineralized water tank is measured in the following manner: A ThermoFsiher 410iQ carbon dioxide analyzer is used to detect the CO2 concentration inside and outside the floating roof. The gas concentration inside the floating roof is measured by a pipe with an opening at the edge of the floating roof (the pipe opening is equipped with a switch). The pipe is opened and samples are taken for testing.

[0097] The conductivity test results were displayed by an online conductivity meter connected to the demineralized water tank in the central control room.

[0098] The bending strength parameters were measured using the three-point bending test method for polypropylene (GB / T 9341-2008).

[0099] In the following embodiments, the foamed polypropylene sheet-1 is obtained by supercritical carbon dioxide foaming of injection-molded polypropylene sheet-1; the water contact angle is 125° and the density is 0.1 g / cm³. 3 The surface irregular shape has an average size of 110μm, a height of 0.5-12μm, no through holes, and a bending strength of 0.14MPa.

[0100] Foamed polypropylene sheet-2 is produced by supercritical carbon dioxide foaming of injection-molded polypropylene sheet-2 (a blend of 60 wt% random copolymer polypropylene E02ES and 40 wt% homopolymer polypropylene T30S, purchased from Zhejiang Jiaxing Xinhengtai New Material Co., Ltd.), with a water contact angle of 112° and a density of 0.08 g / cm³. 3 The surface irregular shape has an average size of 140μm, a height of 0.5-15μm, no through holes, and a bending strength of 0.10MPa.

[0101] Foamed polypropylene sheet-3 is produced by supercritical carbon dioxide foaming of injection-molded polypropylene sheet-3 (random copolymer polypropylene E02ES, purchased from Ningbo Zhiwei New Material Technology Co., Ltd.). It has a water contact angle of 118° and a density of 0.03 g / cm³. 3 The surface irregular shape has an average size of 100μm, a height of 0.5-10μm without through holes, and a bending strength of 0.08MPa.

[0102] The average size of irregular shapes in foamed polypropylene sheets refers to the average size of 5 images taken from the sheet surface using SEM, the longest irregular shape selected using Nano Measure software, and the average size of the 5 images.

[0103] Injection-molded polypropylene sheet-1 (a blend of 68wt% random copolymer polypropylene E02ES and 32wt% POE, purchased from Jiangsu Suzhou Shensai New Material Co., Ltd.), with a smooth and flat surface, no irregular structure, and a flexural strength of 7.5MPa.

[0104] Injection-molded polypropylene sheet-2 (a blend of 60wt% random copolymer polypropylene E02ES and 40wt% homopolymer polypropylene T30S), purchased from Zhejiang Jiaxing Xinhengtai New Material Co., Ltd., with a smooth and flat surface, no irregular structure, and a flexural strength of 9.5MPa.

[0105] Injection-molded polypropylene sheet-3 (random copolymer polypropylene E02ES), purchased from Ningbo Zhiwei New Material Technology Co., Ltd., with a smooth and flat surface, no irregular structure, and a flexural strength of 7.0 MPa.

[0106] Maleic anhydride (Xilong Scientific Co., Ltd.), acrylic acid (Sinopharm Chemical Reagent Co., Ltd.), methacrylic acid (Sinopharm Chemical Reagent Co., Ltd.), 2-acrylamide-2-methylpropanesulfonic acid (Sinopharm Chemical Reagent Co., Ltd.), sodium hydroxide (Xilong Scientific Co., Ltd.), potassium hydroxide (Xilong Scientific Co., Ltd.), calcium hydroxide (Xilong Scientific Co., Ltd.), acetone (Xilong Scientific Co., Ltd.), vinyltrimethoxysilane (Tokyo Chemical Industry Co., Ltd.), vinyl silicone oil (Shandong Dayi Chemical Co., Ltd.), vinyl hydrogen silicone oil (Tokyo Chemical Industry Co., Ltd.), divinyl silicone oil (Shandong Dayi Chemical Co., Ltd.); other raw materials are from commercial sources.

[0107] Example 1

[0108] (1) According to maleic anhydride (heated to 80℃) 5g / cm 2 Vinyl silicone oil 10g / cm 2 Spraying is performed on the surface of foamed polypropylene sheet-1 to obtain pretreated foamed polypropylene sheet-1; 50 parts by weight of sodium hydroxide are dissolved in 100 parts by weight of water-alcohol (water-alcohol mass ratio 70:30).

[0109] (2) The pretreated foamed polypropylene sheet-1 was placed in a microwave reactor and microwave irradiated for 2 seconds at a pressure of 2 MPa and an irradiation power of 50 kW. The microwave irradiation was repeated 5 times with an interval of 1 min each time. Then, the microwave-irradiated product was subjected to a salting reaction in the sodium hydroxide aqueous alcohol solution prepared in step (1), while removing the vinyl silicone oil and sodium maleate that did not participate in the grafting reaction. The product was then washed with deionized water and finally dried in an 80°C blast furnace to obtain low-density polypropylene material S1. The test results of water contact angle, hydrophilic side group surface grafting rate, oil contact angle, oleophilic side group surface grafting rate, flexural strength, and surface irregular structure size are shown in Tables 1 and 2.

[0110] (3) Assemble multiple low-density polypropylene sheets S1 with a polyurethane elastomer-based isolation sheet and frame to obtain a flexible floating roof component Q1.

[0111] The carbon dioxide concentration and water conductivity of the flexible floating roof component Q1, both inside and outside, are listed in Table 3.

[0112] Example 2

[0113] (1) According to acrylic acid 0.1g / cm 2 Vinyl hydrosilicone oil 0.2g / cm 2 Spraying is performed on the surface of foamed polypropylene sheet-2 to obtain pretreated foamed polypropylene sheet-2; 30 parts by weight of sodium hydroxide are dissolved in 100 parts by weight of water-alcohol (water-alcohol mass ratio 80:20).

[0114] (2) The pretreated foamed polypropylene sheet-2 was placed in a microwave reactor and microwave irradiated for 30s at a pressure of 1.5MPa and an irradiation power of 80kW; this was repeated 5 times with a 5min interval between each cycle; then the microwave-irradiated product was subjected to a salting reaction in the sodium hydroxide aqueous alcohol solution prepared in step (1), while removing the vinyl silicone oil and sodium acrylate that did not participate in the grafting reaction. The product was then washed with deionized water, and finally dried in a forced-air dryer at 80℃ to obtain low-density polypropylene sheet S2.

[0115] The test results for water contact angle, hydrophilic side grafting rate, oil contact angle, oleophilic side grafting rate, bending strength, and surface irregular structure size are shown in Tables 1 and 2.

[0116] (3) Assemble multiple low-density polypropylene sheets S2 with a polyurethane elastomer-based isolation sheet and frame to obtain a flexible floating roof component Q2.

[0117] The carbon dioxide concentration and water conductivity of the flexible floating roof component Q2, both inside and outside, are listed in Table 3.

[0118] Example 3

[0119] (1) According to methacrylic acid 4g / cm 2 Divinyl silicone oil and 8g / cm 2 The surface of the foamed polypropylene sheet-3 is sprayed to obtain the pretreated foamed polypropylene sheet-3; 20 parts by weight of potassium hydroxide are dissolved in 100 parts by weight of water-alcohol (water-alcohol mass ratio 60:40).

[0120] (2) The pretreated foamed polypropylene sheet-3 was placed in a microwave reactor and microwave irradiated for 10s at a pressure of 0.5MPa and an irradiation power of 20kW; this was repeated 3 times with a 5min interval between each cycle; then the microwave-irradiated product was subjected to a salting reaction in the sodium hydroxide aqueous alcohol solution prepared in step (1), while removing the divinyl silicone oil and sodium acrylate that did not participate in the grafting reaction. The product was then washed with deionized water, and finally dried in an 80℃ forced-air drying oven to obtain low-density polypropylene sheet S3.

[0121] The test results for water contact angle, hydrophilic side grafting rate, oil contact angle, oleophilic side grafting rate, bending strength, and surface irregular structure size are shown in Tables 1 and 2.

[0122] (3) Assemble multiple low-density polypropylene sheets S3 with a polyurethane elastomer-based isolation sheet and frame to obtain a flexible floating roof component Q3.

[0123] The carbon dioxide concentration and water conductivity of the flexible floating roof component Q3, both inside and outside, are listed in Table 3.

[0124] Example 4

[0125] The method of Example 1 was followed, except that in step (2), microwave irradiation was performed for 2 seconds at a pressure of 8 MPa and an irradiation power of 50 kW; microwave irradiation was repeated 5 times with an interval of 1 minute between each irradiation; the other conditions were the same as in Example 1. Low-density polypropylene material S4 was obtained.

[0126] The test results for water contact angle, hydrophilic side grafting rate, oil contact angle, oleophilic side grafting rate, bending strength, and surface irregular structure size are shown in Tables 1 and 2.

[0127] (3) Assemble multiple low-density polypropylene sheets S4 with a polyurethane elastomer-based isolation sheet and frame to obtain a flexible floating roof component Q4.

[0128] The carbon dioxide concentration and water conductivity of the flexible floating roof component Q4, both inside and outside, are listed in Table 3.

[0129] Example 5

[0130] The method is the same as in Example 1, except that in step (1), the amount of maleic anhydride coating on the surface of the foamed polypropylene sheet-1 is 8 g / cm³. 2 The vinyl silicone oil coating amount is 15 g / cm². 2 The remaining conditions are the same as in Example 1. Low-density polypropylene material S5 is obtained.

[0131] The test results for water contact angle, hydrophilic side grafting rate, oil contact angle, oleophilic side grafting rate, bending strength, and surface irregular structure size are shown in Tables 1 and 2.

[0132] (3) Assemble multiple low-density polypropylene sheets S5 with a polyurethane elastomer-based isolation sheet and frame to obtain a flexible floating roof component Q5.

[0133] The carbon dioxide concentration and water conductivity of the flexible floating roof component Q5, both inside and outside, are listed in Table 3.

[0134] Comparative Example 1

[0135] Following the method of Example 1, except that injection-molded polypropylene sheet-1 was used, while the other conditions remained the same, sheet D1 was obtained.

[0136] Multiple sheets D1 are assembled with a polyurethane elastomer-based insulating sheet and frame to obtain a flexible floating roof component DQ1.

[0137] The carbon dioxide concentration and water conductivity of the flexible floating roof component DQ1, both inside and outside, are listed in Table 3.

[0138] Comparative Example 2

[0139] Following the method of Example 2, except that injection-molded polypropylene sheet-2 was used, while the other conditions remained the same, sheet D2 was obtained.

[0140] Multiple sheets D2 are assembled with a polyurethane elastomer-based insulating sheet and frame to obtain the flexible floating roof component DQ2.

[0141] The carbon dioxide concentration and water conductivity of the flexible floating roof DQ2, both inside and outside, are listed in Table 3.

[0142] Comparative Example 3

[0143] Following the method of Example 3, except that injection-molded polypropylene sheet-3 was used, while the other conditions remained the same, sheet D3 was obtained.

[0144] Multiple sheets of D3 are assembled with a polyurethane elastomer-based insulating sheet and frame to obtain the flexible floating roof component DQ3.

[0145] The carbon dioxide concentration and water conductivity of the flexible floating roof component DQ3, both inside and outside, are listed in Table 3.

[0146] Comparative Example 4

[0147] The method of Example 1 differs in that, in step (2), no pressure is applied during the microwave irradiation process, specifically:

[0148] The pretreated foamed polypropylene sheet-1 was placed in a microwave reactor and irradiated for 2 seconds at an irradiation power of 50 kW under normal pressure; the microwave irradiation was repeated 5 times, with an interval of 1 minute between each irradiation; the remaining conditions were the same as in Example 1. Sheet D4 was obtained.

[0149] Multiple sheets of D4 are assembled with a polyurethane elastomer-based insulating sheet and frame to obtain the flexible floating roof component DQ4.

[0150] The carbon dioxide concentration and water conductivity of the flexible floating roof component DQ4, both inside and outside, are listed in Table 3.

[0151] Comparative Example 5

[0152] The demineralized water tank is not equipped with a floating roof. Its surface carbon dioxide concentration and water conductivity are listed in Table 3.

[0153] Table 1

[0154]

[0155] Table 2

[0156]

[0157] Table 3

[0158]

[0159] As can be seen from the results in Tables 1 and 2, compared with injection-molded polyolefins with smooth surfaces, the present invention significantly improves the hydrophilic and oleophilic properties of foamed polyolefin surfaces without affecting mechanical properties, and even reaches the level of superhydrophilic and superoleophilic properties.

[0160] As can be seen from Table 3, the low-density polyolefin sheet provided by the present invention can significantly block carbon dioxide and reduce the conductivity of demineralized water.

[0161] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A device for isolating carbon dioxide, characterized by The device is internally provided with a flexible floating roof assembly, which comprises: an annular elastomer and a low-density polyolefin sheet nested in the annular elastomer; wherein the low-density polyolefin sheet includes a low-density polyolefin base material and hydrophilic side groups and oleophilic side groups grafted to the surface of the low-density polyolefin base material; and the surface of the low-density polyolefin sheet has a plurality of irregular structures with an average size of not less than 100 μm and not more than 5 mm, a height of not more than 20 μm and not less than 0.5 μm; the sheet surface contains 5 to 120 irregular structures per cm 2 ; the surface grafting rate of the hydrophilic side groups is 10 to 50%, and the surface grafting rate of the oleophilic side groups is 10 to 50%.

2. The device according to claim 1, wherein, the water contact angle of the surface of the sheet is < 30°; and / or, the white oil contact angle of the surface of the sheet is < 30°; and / or, the sheet is free of through holes.

3. The device according to claim 2, wherein, the water contact angle of the surface of the sheet is 0-20°; and / or, the white oil contact angle of the surface of the sheet is 0-20°.

4. The device according to claim 3, wherein, the water contact angle of the surface of the sheet is 0°; and / or, the white oil contact angle of the surface of the sheet is 0°.

5. The device according to claim 1, wherein, the surface grafting rate of the hydrophilic side group is 20-50%; and / or, the surface grafting rate of the lipophilic side group is 20-50%.

6. The apparatus of claim 1, wherein, The low density polyolefin substrate has a density of less than 0.2 g / cm 3 ; and / or, the low-density polyolefin substrate is selected from thermoplastic polyolefins; and / or, the low-density polyolefin substrate comprises polypropylene; and / or the low density polyolefin substrate has a weight average molecular weight of 10 4 -10 6 g / mol.

7. The apparatus of claim 6, wherein, The low density polyolefin substrate has a density of not more than 0.1 g / cm 3 ; and / or, the low-density polyolefin substrate comprises polypropylene, and the content of the polypropylene is not less than 50 wt% based on the total mass of the low-density polyolefin substrate.

8. The apparatus of claim 6, wherein, the polypropylene is selected from at least one of homopolymer polypropylene, random copolymer polypropylene and impact copolymer polypropylene; and / or, the low-density polyolefin substrate further comprises polyethylene and / or polyolefin elastomer.

9. The device according to claim 1, wherein, the hydrophilic side group is a monomer side group containing at least one heteroatom of oxygen, sulfur, nitrogen, silicon and halogen and containing a carbon-carbon double bond; and / or, the monomer of the hydrophilic side group is at least one of an organic acid containing a carbon-carbon double bond, a derivative of an organic acid containing a carbon-carbon double bond, a salt of an organic acid containing a carbon-carbon double bond and a vinyl-containing silane; wherein the salt of the organic acid containing a carbon-carbon double bond is a product after salification of the organic acid containing a carbon-carbon double bond and / or a product after salification of the derivative of the organic acid containing a carbon-carbon double bond; and / or, the organic acid derivative includes at least one of anhydride of the organic acid and ester containing the organic acid; and / or, the vinyl-containing silane is one or more of the compounds represented by formula (A): CH2=CH2(CH2) n SiX3formula (A) wherein n is an integer of 0-3, and X is at least one of halogen, methoxy, ethoxy, acetoxy; and / or, the lipophilic side group is a vinyl-containing silicone oil side group and / or a styrene-containing side group; and / or, the monomer of the lipophilic side group is a terminal vinyl silicone oil and / or a high-vinyl silicone oil.

10. The device according to claim 9, wherein, the monomer of the lipophilic side group is at least one of a vinyl silicone oil, a methyl vinyl silicone oil, a vinyl-containing hydrogen silicone oil and a divinyl silicone oil.

11. The device according to claim 1, wherein, the monomer of the hydrophilic side group is at least one of maleic anhydride, a maleic anhydride derivative, methacrylic acid and its derivatives, vinyl acetate, an alkenyl sulfonic acid and its derivatives, p-styrene carboxylic acid, p-styrene acetic acid, itaconic acid, oleic acid and arachidonic acid, and / or their salt forms.

12. The apparatus according to claim 11, wherein the monomer of the hydrophilic side group is at least one of maleic anhydride, maleic anhydride derivatives, methacrylic acid, and methacrylic acid derivatives, and / or their salt forms.

13. The apparatus according to claim 12, wherein the monomer of the hydrophilic side group is maleic anhydride and / or maleic anhydride salt forms.

14. The apparatus of claim 1, wherein, the low-density polyolefin sheet has a bending strength of 0.01-0.5 MPa.

15. The apparatus of claim 14, wherein, the low-density polyolefin sheet has a bending strength of 0.01-0.15 MPa.

16. The apparatus according to claim 1, wherein a connecting member for connecting the annular elastic body and the low-density polyolefin sheet is further provided between the annular elastic body and the low-density polyolefin sheet.

17. The apparatus according to claim 16, wherein the annular elastic body material is selected from at least one of styrene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, and rubbers.

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