Water-resistant channel door gating composite material and preparation method and application thereof

Abstract

The present application relates to gas purification and carbon dioxide resource utilization technology field, disclose a kind of water-resistant pore door control composite material and its preparation method and application.The composite material includes pore door control desulfurization component and hydrophobic polymer component;Pore door control desulfurization component includes gamma-FeOOH reaction trapping phase and high-silicon MFI type molecular sieve door control layer located on its outside, and hydrophobic polymer component is one or more of polydivinylbenzene polymer powder, polydivinylbenzene polymer particle, high polymer hydrophobic treatment layer located on the outer surface of pore door control desulfurization component.The present application makes H2S first through molecular sieve channel or orifice and then contact gamma-FeOOH by door control layer, reduce the direct interference of CO2, water vapor and non-target impurities;And hydrophobic polymer component can form local hydrophobic microenvironment, reduce water molecules into molecular sieve channel and gamma-FeOOH adsorption site, so as to protect the H2S adsorption site of gamma-FeOOH.The material is suitable for deep removal of CO2 rich atmosphere.

Description

Technical Field

[0001] This invention relates to the fields of gas purification and carbon dioxide resource utilization, and in particular to a water-resistant pore-gated composite material for deep removal of trace amounts of hydrogen sulfide and carbonyl sulfur from feedstock gas for carbon dioxide hydrogenation to olefins, its preparation method, and its application. Background Technology

[0002] Carbon dioxide hydrogenation to olefins converts CO2 and hydrogen into low-carbon olefins such as ethylene, propylene, and butene, representing an important direction for CO2 resource utilization and green chemical engineering. This process typically employs metal oxides, molecular sieves, or metal oxide-molecular sieve composite catalysts as the catalytic system. The catalysts require high purity feed gas, particularly sensitive to sulfur-containing impurities such as hydrogen sulfide and carbonyl sulfide. Even ppm-level sulfur-containing impurities can interact with metal sites, oxygen vacancies, acidic sites, or molecular sieve channels, leading to decreased catalyst activity, altered selectivity, or shortened catalyst lifetime.

[0003] In actual processes, carbon dioxide feed gas may originate from capture, purification, conversion, decarbonization, or recycle processes, often containing high concentrations of CO2 and small amounts of H2, CO, CH4, C2 hydrocarbons, C3 hydrocarbons, methanol, H2S, and COS. For example, the CO2 content in the carbon dioxide product gas can exceed 90 vol%, H2S can be at levels ranging from several ppm to tens of ppm, and COS may be at levels ranging from sub-ppm to several ppm. If the hydrogen mainly originates from water electrolysis, the hydrogen may still carry trace amounts of water vapor after condensation and drying. This water vapor, upon entering the desulfurization bed, easily competes with H2S for adsorption, reducing the capture efficiency of the desulfurization material for trace amounts of H2S.

[0004] γ-FeOOH exhibits reactive trapping ability for H2S and can be used as a low-temperature desulfurization adsorbent. For example, patent CN107572593A discloses a method for preparing γ-FeOOH, and the desulfurizing agent prepared from γ-FeOOH is used for H2S removal with good sulfur capacity. However, in feed gas containing high concentrations of CO2 and trace amounts of water vapor, the open surface of γ-FeOOH is easily contacted by CO2, water molecules, and other impurities, leading to the occupation of H2S adsorption sites or shielding of reaction sites. Simply physically mixing γ-FeOOH with high-silica molecular sieves can reduce the influence of CO2 or water molecules to some extent, but a large proportion of the γ-FeOOH surface is still directly exposed to the complex gas flow, making it difficult to fully utilize the pore sieving and microenvironment regulation functions of the molecular sieves.

[0005] High-silica MFI molecular sieves possess a regular 10-membered ring microporous structure and a relatively hydrophobic framework environment. If considered simply as a low CO2 affinity material combined with γ-FeOOH, its technical performance is easily predictable using existing technologies. To improve the material's selectivity and anti-interference capabilities, it is necessary to further transform the open reaction surface of γ-FeOOH into an inner reaction surface accessible through the molecular sieve channels, allowing H2S to pass through the molecular sieve channels or pores before contacting γ-FeOOH. Consequently, the hydrogen sulfide adsorption sites of γ-FeOOH can be protected by the molecular sieve gating layer, preventing larger impurities and components prone to surface covering from directly contacting the γ-FeOOH reaction trapping phase. Furthermore, water molecules are small; if water vapor is present, water molecules can enter the molecular sieve channels or form competitive adsorption on the γ-FeOOH surface, reducing H2S capture efficiency. Therefore, a high-silica MFI gating layer alone is insufficient to handle CO2 feed gas containing water. It is necessary to further construct a hydrophobic microenvironment near the pore-gated desulfurization components to prevent water molecules from entering the molecular sieve channels and γ-FeOOH reaction sites, while maintaining the mass transfer channels of H2S, thereby improving the deep desulfurization performance in water-containing CO2-enriched atmospheres. Summary of the Invention

[0006] This invention addresses the problem that existing γ-FeOOH desulfurization technologies for carbon dioxide hydrogenation to olefins feedstock gas are susceptible to CO2 or water molecule interference, resulting in poor desulfurization performance. It provides a water-resistant pore-gated composite material, its preparation method, and its application. This material achieves selective desulfurization and purification of carbon dioxide hydrogenation to olefins feedstock gas, recycle gas, or protective gas containing high CO2, water, and trace amounts of H2S and COS through the synergistic effect of pore-gated desulfurization components comprising a γ-FeOOH reactive trapping phase and a high-silica MFI molecular sieve gating layer, as well as hydrophobic polymer components.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A water-resistant pore-gated composite material includes a pore-gated desulfurization component and a hydrophobic polymer component; the pore-gated desulfurization component includes a γ-FeOOH reactive trapping phase and a high-silica MFI molecular sieve gated layer located outside the γ-FeOOH reactive trapping phase; the hydrophobic polymer component is one or more of polyvinylbenzene polymer powder, polyvinylbenzene polymer particles, and a polymer hydrophobic treatment layer located on the outer surface of the pore-gated desulfurization component.

[0008] The main reason for setting a high-silica MFI molecular sieve gated layer on the outside of the γ-FeOOH reactive trapping phase in this invention is to protect the H2S adsorption sites of γ-FeOOH. Specifically, after the high-silica MFI molecular sieve gated layer is placed outside the γ-FeOOH reactive trapping phase, γ-FeOOH is no longer directly exposed to the CO2-enriched atmosphere as a large open surface, but exists as a reactive trapping phase behind the molecular sieve channels or inside the pores. The main reason is that the high-silica MFI molecular sieve gated layer has a 10-membered ring microporous structure, which allows H2S to reach the γ-FeOOH reactive trapping phase while restricting non-target molecules with kinetic sizes larger than H2S from entering the region where the γ-FeOOH reactive trapping phase is located. Therefore, H2S first passes through the channels or pores of the high-silica MFI molecular sieve and then reacts with and traps γ-FeOOH. This structure can reduce the direct coverage of the γ-FeOOH surface by CO2, water vapor, and larger non-target components, thereby improving the effective utilization rate of ppm-level H2S.

[0009] Meanwhile, the addition of hydrophobic polymer components can further protect the H2S adsorption sites of γ-FeOOH, reducing the entry of water molecules into the molecular sieve channels. The hydrogen used in the hydrogenation of carbon dioxide to olefins can mainly be derived from water electrolysis, and trace amounts of water vapor may be present in the actual gas flow. After water molecules enter the molecular sieve channels, they compete with H2S for diffusion and adsorption, and can occupy active sites on the γ-FeOOH surface. This invention, by blending with polyvinylbenzene (PDVB) polymer powder or particles, and / or by applying a polymeric hydrophobic treatment to the outer surface of the pore-gated desulfurization component, creates a localized hydrophobic microenvironment in the material, making it difficult for water molecules to enter the molecular sieve channels or occupy the H2S adsorption sites of γ-FeOOH. Specifically, when the hydrophobic polymer component is a hydrophobic treatment layer located on the outer surface of the pore-gated desulfurization component, it will not completely block the pores of the high-silicon MFI type molecular sieve gate layer, allowing H2S to pass through the high-silicon MFI type molecular sieve channels or pores and then react with and be captured by γ-FeOOH.

[0010] Therefore, the synergistic effect of the two aspects significantly improves the deep desulfurization effect of water-resistant pore-gated composite materials on feed gas, circulating gas or protective gas for carbon dioxide hydrogenation to olefins with high CO2 and water content.

[0011] Preferably, the pore-gated desulfurization component is a core-shell structured particle, wherein the γ-FeOOH reaction trapping phase is the core and the high-silica MFI molecular sieve gate layer is the outer shell; the γ-FeOOH reaction trapping phase is γ-FeOOHH loaded on the high-silica MFI molecular sieve.

[0012] Preferably, the high-silica MFI molecular sieve gate layer is a Silicalite-1 molecular sieve layer or an MFI molecular sieve layer with a Si / Al molar ratio of not less than 100.

[0013] Preferably, the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles are one or more of nonporous polyvinylbenzene, microporous polyvinylbenzene, mesoporous polyvinylbenzene, and nanoporous polyvinylbenzene; the polymer hydrophobic treatment layer includes one or more of the following: polyvinylbenzene layer, in-situ polymerized divinylbenzene layer, polystyrene layer, polytetrafluoroethylene layer, polyolefin layer, fluoropolymer layer, and hydrophobic organosilicon polymer layer.

[0014] The present invention also provides a method for preparing the above-mentioned water-resistant channel-gated composite material, comprising the following steps: S1. Preparation of the γ-FeOOH reaction trapping phase; S2. A high-silica MFI molecular sieve gated layer is formed on the outside of the γ-FeOOH reaction trapping phase to obtain a pore-gated desulfurization component; S3. Physically blend the pore-gated desulfurization component with polyvinylbenzene polymer powder or polyvinylbenzene polymer particles, and / or perform hydrophobic treatment on the outer surface of the pore-gated desulfurization component to form a polymer hydrophobic treatment layer, thereby obtaining a water-resistant pore-gated composite material.

[0015] Compared to packing hydrophobic components independently in a bed far from the desulfurization components, close-range physical blending allows water molecules to migrate more quickly from around the pore-gated desulfurization components, thereby reducing the probability of water molecules remaining at the molecular sieve pores and the γ-FeOOH surface. The polymer hydrophobic treatment layer can be a discontinuous layer, an island-like distribution layer, a dotted attachment layer, a thin film layer, or a porous coating layer. This treatment layer does not completely block the pores of the MFI-type molecular sieve, allowing H2S to still pass through the hydrophobic treatment layer and the molecular sieve-gated layer to reach the γ-FeOOH reaction trapping phase.

[0016] Preferably, in step S1, the γ-FeOOH reaction trapping phase is obtained by iron salt hydrolysis, precipitation oxidation, hydrothermal conversion or air oxidation; the iron salt is selected from one or more of ferric nitrate, ferric chloride, ferric sulfate, ferric acetate and ferric oxalate.

[0017] Preferably, in step S2, the high-silicon MFI molecular sieve gated layer is formed by seed-assisted growth, in-situ crystallization, secondary growth, molecular sieve nanocrystal assembly, molecular sieve sol deposition, or a combination thereof.

[0018] Preferably, in step S3, the mass ratio of the pore-gated desulfurization component to polyvinylbenzene polymer particles or polyvinylbenzene polymer powder is 1:0.01~20; and the thickness of the polymer hydrophobic treatment layer is 1~500 nm.

[0019] Preferably, in step S3, the hydrophobic treatment is performed by: contacting the pore-gated desulfurization component with a treatment liquid containing divinylbenzene, an initiator, and a solvent for in-situ polymerization to obtain a pore-gated desulfurization component with a hydrophobic surface; or, contacting the pore-gated desulfurization component with a polyvinylbenzene dispersion, a polystyrene dispersion, a polytetrafluoroethylene dispersion, a polyolefin dispersion, a fluoropolymer dispersion, or a hydrophobic organosilicon polymer dispersion, followed by impregnation, stirring, spraying, filtration, drying, or curing to obtain a pore-gated desulfurization component with a hydrophobic surface.

[0020] Preferably, the pore-gated desulfurization component is a composite particle of γ-FeOOH reaction trapping phase confined in the pores or intercrystalline micropores of a high-silica MFI molecular sieve; the γ-FeOOH reaction trapping phase is γ-FeOOH.

[0021] For water-resistant pore-gated composite materials containing confined pore-gated desulfurization components, the present invention also provides a corresponding preparation method, including the following steps: N1. Preparation of high-silica MFI molecular sieves; N2. High-silicon MFI molecular sieve is impregnated with iron salt, and then treated with ammonia vapor to hydrolyze and deposit iron species near the pore openings and intercrystalline micropores of the high-silicon MFI molecular sieve. After aging, a pore-gated desulfurization component with a high-silicon MFI molecular sieve gated layer on the outside of the γ-FeOOH reaction trapping phase is obtained. N3. Physically blend the pore-gated desulfurization component with polyvinylbenzene polymer powder or polyvinylbenzene polymer particles, and / or perform hydrophobic treatment on the outer surface of the pore-gated desulfurization component to form a polymer hydrophobic treatment layer, thereby obtaining a water-resistant pore-gated composite material.

[0022] Finally, the present invention also provides the application of the aforementioned water-resistant pore-gated composite material in the selective removal of H2S and / or COS in a CO2-enriched atmosphere. Preferably, the CO2-enriched atmosphere is a feed gas, recycle gas, or protective gas for carbon dioxide hydrogenation to olefins containing CO2, H2, H2S, COS, water vapor, and low-carbon hydrocarbons. Alternatively, the water-resistant pore-gated composite material can be used to protect the catalyst during the carbon dioxide hydrogenation to olefins process. Preferably, the carbon dioxide hydrogenation to olefins catalyst includes metal oxides, molecular sieves, metal oxide-molecular sieve composite catalysts, or combinations thereof.

[0023] Therefore, the present invention has the following beneficial effects: (1) The pore-gated desulfurization component of the present invention is not a simple mixture of high-silicon MFI molecular sieve and γ-FeOOH, but a high-silicon MFI molecular sieve gated layer is formed on the outside of the γ-FeOOH reaction trapping phase through core-shell, coating or confinement structures, so that the open reaction surface of γ-FeOOH is transformed into the inner reaction surface that can be reached by the molecular sieve pores. Therefore, H2S needs to pass through the micropores or pores of the MFI molecular sieve before reaching the γ-FeOOH reaction trapping phase, thus protecting the H2S adsorption sites of γ-FeOOH structurally. (2) The high-silica MFI molecular sieve gate layer design can reduce the direct interference of high concentration CO2 and large-sized non-target components on the γ-FeOOH surface, so that the H2S reaction trapping occurs more concentratedly on the protected γ-FeOOH sites; (3) The pore-gated desulfurization component is blended with the hydrophobic polymer component PDVB polymer particles or powder, or the surface of the pore-gated desulfurization component is treated with polymer hydrophobic treatment, which can build a hydrophobic microenvironment around the pore-gated desulfurization component, reduce the entry of water molecules into the molecular sieve pores and γ-FeOOH sites, thus adapting to the scenario of carbon dioxide hydrogenation to olefins where hydrogen is mainly produced by electrolysis of water. (4) This invention addresses the practical problem of high CO2, trace H2S, trace COS and trace water vapor coexisting in the feed gas of carbon dioxide hydrogenation to olefins. It can deeply remove ppm-level sulfur impurities at room temperature or low temperature to protect the subsequent carbon dioxide hydrogenation to olefins catalyst. Attached Figure Description

[0024] Figure 1 The results are from stability tests on catalysts for the hydrogenation of carbon dioxide to olefins after desulfurization. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0026] General Implementation Examples In a first aspect, a water-resistant pore-gated composite material includes a pore-gated desulfurization component and a hydrophobic polymer component; the pore-gated desulfurization component includes a γ-FeOOH reaction trapping phase and a high-silica MFI molecular sieve gated layer located outside the γ-FeOOH reaction trapping phase; the hydrophobic polymer component is one or more of polyvinylbenzene polymer powder, polyvinylbenzene polymer particles, and a polymer hydrophobic treatment layer located on the outer surface of the pore-gated desulfurization component.

[0027] In some specific embodiments, the pore-gated desulfurization component is a core-shell structured particle, wherein the γ-FeOOH reactive trapping phase is the core and the high-silica MFI molecular sieve gate layer is the outer shell, and the γ-FeOOH reactive trapping phase is γ-FeOOH loaded on the high-silica MFI molecular sieve; or, the γ-FeOOH reactive trapping phase is a composite particle confined in the pores or intercrystalline micropores of the high-silica MFI molecular sieve, wherein the γ-FeOOH reactive trapping phase is γ-FeOOH.

[0028] In some specific embodiments, the direct exposure ratio of the γ-FeOOH reaction trapping phase on the outer surface of the pore-gated desulfurization component is less than 30%; in some more preferred embodiments, it is less than 20%; and in the best embodiment, it is less than 10%.

[0029] In some specific embodiments, the high-silica MFI molecular sieve gate layer is a Silicalite-1 molecular sieve layer or an MFI molecular sieve layer with a Si / Al molar ratio of not less than 100; in some more preferred embodiments, the high-silica MFI molecular sieve gate layer is an MFI molecular sieve layer with a Si / Al molar ratio of not less than 300; in the best embodiment, the high-silica MFI molecular sieve gate layer is an all-silica MFI molecular sieve layer.

[0030] In some specific embodiments, the thickness of the high-silica MFI molecular sieve gate layer is 5~1000 nm; in some more preferred embodiments, the thickness is 10~500 nm; and in the best embodiment, the thickness is 20~200 nm.

[0031] In some specific embodiments, the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles are one or more of nonporous polyvinylbenzene, microporous polyvinylbenzene, mesoporous polyvinylbenzene, and nanoporous polyvinylbenzene; the polymer hydrophobic treatment layer includes one or more of the following: polyvinylbenzene layer, in-situ polymerized divinylbenzene layer, polystyrene layer, polytetrafluoroethylene layer, polyolefin layer, fluoropolymer layer, and hydrophobic organosilicon polymer layer.

[0032] In some specific embodiments, the particle size of polydivinylbenzene polymer powder or polydivinylbenzene polymer particles is 10 nm to 2 mm; in some more preferred embodiments, the particle size is 100 nm to 500 μm; and in the best embodiment, the particle size is 1 to 200 μm.

[0033] In some specific embodiments, the water contact angle of the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles is not less than 100°; in some more preferred embodiments, the water contact angle is not less than 120°; and in the best embodiment, the water contact angle is not less than 140°.

[0034] In some specific embodiments, the polymer hydrophobic treatment layer is a discontinuous layer, an island-shaped distribution layer, a dotted adhesion layer, a thin film layer, or a porous coating layer.

[0035] In some specific embodiments, the thickness of the polymer hydrophobic treatment layer is 1~500 nm; in some preferred embodiments, the thickness is 2~100 nm; and in the most preferred embodiment, the thickness is 5~50 nm.

[0036] Secondly, the preparation method of the above-mentioned water-resistant channel-gated composite material.

[0037] For the case where the pore-gated desulfurization component is a core-shell structured particle consisting of a γ-FeOOH reaction trapping phase and a high-silica MFI molecular sieve, the corresponding preparation method includes the following steps: S1. Preparation of the γ-FeOOH reaction trapping phase; S2. A high-silica MFI molecular sieve gated layer is formed on the outside of the γ-FeOOH reaction trapping phase to obtain a pore-gated desulfurization component; S3. Physically blend the pore-gated desulfurization component with polyvinylbenzene polymer powder or polyvinylbenzene polymer particles, and / or perform hydrophobic treatment on the outer surface of the pore-gated desulfurization component to form a polymer hydrophobic treatment layer, thereby obtaining a water-resistant pore-gated composite material.

[0038] In some specific embodiments, in step S1, the γ-FeOOH reaction trapping phase is obtained by iron salt hydrolysis, precipitation oxidation, hydrothermal conversion or air oxidation; wherein the iron salt is selected from one or more of ferric nitrate, ferric chloride, ferric sulfate, ferric acetate and ferric oxalate.

[0039] In some specific embodiments, in step S2, the high-silicon MFI type molecular sieve gated layer is formed by seed-assisted growth, in-situ crystallization, secondary growth, molecular sieve nanocrystal assembly, molecular sieve sol deposition, or a combination thereof.

[0040] In some specific embodiments, in step S3, the mass ratio of the pore-gated desulfurization component to polyvinylbenzene polymer particles or polyvinylbenzene polymer powder is 1:0.01~20; in some more preferred embodiments, the mass ratio is 1:0.1~2; in the best embodiment, the mass ratio is 1:0.05~0.2.

[0041] In some specific embodiments, in step S3, the physical blending method includes one or more of the following: powder blending, ball milling blending, grinding blending, granulation blending, extrusion molding blending, and spray granulation blending.

[0042] In some specific embodiments, in step S3, the hydrophobic treatment involves: contacting the pore-gated desulfurization component with a treatment liquid containing divinylbenzene, an initiator, and a solvent for in-situ polymerization to obtain a surface-hydrophobic pore-gated desulfurization component; or, contacting the pore-gated desulfurization component with a polyvinylbenzene dispersion, polystyrene dispersion, polytetrafluoroethylene dispersion, polyolefin dispersion, fluoropolymer dispersion, or hydrophobic organosilicon polymer dispersion, followed by impregnation, stirring, spraying, filtration, drying, or curing to obtain a surface-hydrophobic pore-gated desulfurization component. In some preferred embodiments, the in-situ polymerization is carried out at 60–150°C.

[0043] In some specific embodiments, in step S3, the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles are obtained by thermal polymerization of divinylbenzene in the presence of an initiator; the initiator is selected from one or more of azobisisobutyronitrile, benzoyl peroxide, and persulfate. In some preferred embodiments, the preparation process of the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles includes: mixing divinylbenzene with an initiator, heat-treating at 60~150℃ for 2~48 h, washing and drying to obtain the corresponding particles or powder. In some preferred embodiments, in step S3, the polyvinylbenzene polymer powder or polyvinylbenzene polymer particles are nanoporous polyvinylbenzene, and its preparation process includes: dissolving or dispersing divinylbenzene and an initiator in a porogenic solvent, performing thermal polymerization, washing and drying to obtain nanoporous polyvinylbenzene; the porogenic solvent is selected from one or more of dimethylformamide, ethyl acetate, toluene, n-hexane, and ethanol.

[0044] For composite particles in which the pore-gated desulfurization component is a γ-FeOOH reaction trapping phase confined within the pores or intercrystalline micropores of a high-silica MFI molecular sieve, the corresponding preparation method includes the following steps: N1. Preparation of high-silica MFI molecular sieves; N2. High-silicon MFI molecular sieve is impregnated with iron salt, and then treated with ammonia vapor to hydrolyze and deposit iron species near the pore openings and intercrystalline micropores of the high-silicon MFI molecular sieve. After aging, a pore-gated desulfurization component with a high-silicon MFI molecular sieve gated layer on the outside of the γ-FeOOH reaction trapping phase is obtained. N3. Physically blend the pore-gated desulfurization component with polyvinylbenzene polymer powder or polyvinylbenzene polymer particles, and / or perform hydrophobic treatment on the outer surface of the pore-gated desulfurization component to form a polymer hydrophobic treatment layer, thereby obtaining a water-resistant pore-gated composite material.

[0045] In some specific implementations, step N3 refers to step S3 as described above, and will not be repeated here.

[0046] Thirdly, the aforementioned water-resistant pore-gated composite materials are used for the selective removal of H2S and / or COS in CO2-enriched atmospheres; or for protecting catalysts during the hydrogenation of carbon dioxide to olefins.

[0047] In some specific embodiments, the CO2 enrichment atmosphere is one of the following: CO2 hydrogenation to olefins feedstock gas, CO2 hydrogenation to olefins recycle gas, CO2 hydrogenation to olefins protective gas, syngas purification gas, natural gas decarbonization tail gas, biogas purification gas, or CO2-rich gas after flue gas capture. In some more preferred embodiments, the CO2 enrichment atmosphere is a CO2 hydrogenation to olefins feedstock gas, recycle gas, or protective gas containing CO2, H2, H2S, COS, water vapor, and low-carbon hydrocarbons. More specifically, the CO2 volume fraction in the CO2 hydrogenation to olefins feedstock gas is 10-99.9%, the H2 volume fraction is 0.01-10%, the H2S volume fraction is 0.01-100 ppm, the COS volume fraction is 0.01-20 ppm, and the water vapor volume fraction is 0.001-5%.

[0048] In some specific embodiments, the H2 in the feed gas for carbon dioxide hydrogenation to olefins originates from one or more of the following: hydrogen production by water electrolysis, industrial by-product hydrogen, hydrogen production by natural gas reforming, and hydrogen production by methanol cracking; in some more preferred embodiments, the H2 originates from hydrogen production by water electrolysis.

[0049] In some specific implementations, the desulfurization temperature for removing H2S and / or COS is 0~120℃, the reaction pressure is 0.01~5.0 MPa, and the gas hourly space velocity is 500~100000 mL·g -1 ·h -1 In some preferred embodiments, the desulfurization temperature is 10~60℃.

[0050] In some specific embodiments, in a room temperature atmosphere containing 5-10 ppm H2S, 50-98 vol% CO2, and water vapor, the water-resistant pore-gated composite material can control the outlet H2S concentration to below 0.1 ppm; in a room temperature atmosphere containing 10 ppm H2S, 60 vol% CO2, and water vapor, the H2S breakthrough time of the water-resistant pore-gated composite material is increased by at least 20%, and even at least 50%, compared to the composite material without the introduction of hydrophobic polymer components; in a room temperature atmosphere containing 10 ppm H2S, 60 vol% CO2, and water vapor, the dynamic sulfur capacity of the water-resistant pore-gated composite material is increased by at least 30%, and even at least 60%, compared to the physical mixture of γ-FeOOH and high-silica MFI molecular sieves.

[0051] In some specific embodiments, the catalyst for the hydrogenation of carbon dioxide to olefins includes metal oxides, molecular sieves, metal oxide-molecular sieve composite catalysts, or combinations thereof.

[0052] The present invention will be described in more detail below through embodiments, comparative examples, and test examples. The following embodiments are only used to illustrate the technical solutions of the present invention and should not be considered as limiting the scope of the present invention.

[0053] The following examples focus on the structural form of the pore-gated desulfurization components, the Si / Al ratio of the high-silica MFI molecular sieve gate layer, the introduction method of the hydrophobic polymer components, and their mass ratio. Unless otherwise specified, deionized water was used, the drying temperature was 80 °C, and the drying time was 12 h. All composite materials were sieved to obtain 40-60 mesh particles before testing. To avoid phase inversion of γ-FeOOH under high-temperature and strong alkaline conditions, the examples involving the construction of the S-1 shell adopted a low-temperature assembly method of pre-formulated template-free Silicalite-1 (S-1) nanocrystals and low-temperature fixation with tetraethyl orthosilicate (TEOS), without calcination above 300 °C.

[0054] Example 1

[0055] The preparation steps of the γ-FeOOH / S-1 desulfurization component are as follows: (1) Take 5.00 g of S-1 molecular sieve nanorods and add them to 100 mL of ethanol / water mixture. The volume ratio of ethanol to water is 1:1. Disperse the mixture by ultrasonication for 30 min. After centrifugation to collect the solid, redisperse it into 250 mL of deionized water. (2) Add 5.20 g of FeSO4·7H2O to the above dispersion and 10.0 mL of 0.10 mol / L EDTA aqueous solution; under strong stirring, add 1.0 mol / L dilute ammonia dropwise to adjust the pH of the system to 8.0, and then oxidize in air for 1 h; then adjust the pH to 8.0 again with 1.0 mol / L dilute ammonia and continue aging for 2 h; (3) After the reaction is completed, filter and wash with water until sulfate and EDTA are basically removed from the filtrate. Then dry at 85°C for 18 hours to obtain γ-FeOOH / S-1 desulfurization component (denoted as γ-FeOOH / S-1), which is the γ-FeOOH reaction trapping phase.

[0056] Based on the FeSO4·7H2O feed amount, the theoretical yield of γ-FeOOH is 1.67 g, and the theoretical mass fraction of γ-FeOOH in the obtained material is 25 wt%. In this material, γ-FeOOH is mainly deposited and loaded on the outer surface of S-1 molecular sieve.

[0057] Example 2

[0058] The preparation steps of the γ-FeOOH / S-1@S-1 core-shell structured channel-gated desulfurization component are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1 desulfurization component prepared in Example 1, disperse it in 150 mL of ethanol / water mixture, with the volume ratio of ethanol to water being 1:1, adjust the pH of the system to 6.8, sonicate for 10 min and then stir for 30 min. (2) Take 0.50 g of S-1 nanocrystals that have been calcined and detemplated, disperse them in 50 mL of ethanol / water mixture with a volume ratio of ethanol to water of 1:1, and sonicate for 20 min; add the S-1 nanocrystal dispersion to the γ-FeOOH / S-1 dispersion and stir at 25 °C for 3 h to allow the S-1 nanocrystals to adsorb and assemble on the outer surface of γ-FeOOH / S-1. (3) After filtering the obtained solid, it was redispersed in a mixture of 80 mL ethanol and 20 mL water, 0.40 g of TEOS was added, and ammonia was added dropwise to adjust the pH to 8.5. After stirring at room temperature for 4 h, it was aged at 70 °C for 8 h. After filtration, washing with ethanol, washing with water and drying, the core-shell structure pore-gated desulfurization component γ-FeOOH / S-1@S-1 (denoted as γ-FeOOH / S-1@S-1) was obtained.

[0059] The material has a structure of S-1 core / γ-FeOOH continuous intermediate layer / S-1 outer shell layer, wherein the S-1 outer shell layer is an all-silica MFI type molecular sieve layer.

[0060] Example 3

[0061] The preparation steps of the γ-FeOOH / S-1@high-silicon MFI core-shell structure pore-gated desulfurization component with Si / Al=300 are as follows: (1) Disperse the γ-FeOOH / S-1 desulfurization component prepared in Example 1 according to the method of Example 2; (2) Adsorb 0.50 g of S-1 nanocrystals according to the method in Example 2; (3) The obtained solid was then dispersed in a mixture of 80 mL ethanol and 20 mL water, and 0.40 g TEOS and 0.0024 g NaAlO2 were added. The pH was adjusted to 8.5 with ammonia. After stirring at room temperature for 4 h, the mixture was aged at 70 °C for 8 h. The mixture was then filtered, washed and dried to obtain a γ-FeOOH / S-1@MFI core-shell structure pore-gated desulfurization component with a Si / Al molar ratio of 300 (denoted as γ-FeOOH / S-1@MFI300).

[0062] The material has a structure of S-1 core / γ-FeOOH continuous intermediate layer / high silicon MFI outer shell layer with Si / Al=300.

[0063] Example 4

[0064] The preparation steps of γ-FeOOH / S-1@high-silicon MFI core-shell structured pore-gated desulfurization components with Si / Al=100 are as follows: (1) Disperse the γ-FeOOH / S-1 desulfurization component prepared in Example 1 according to the method of Example 2; (2) Adsorb 0.50 g of S-1 nanocrystals according to the method in Example 2; (3) The obtained solid was then dispersed in a mixture of 80 mL ethanol and 20 mL water, and 0.40 g TEOS and 0.0072 g NaAlO2 were added. The pH was adjusted to 8.5 with ammonia. After stirring at room temperature for 4 h, the mixture was aged at 70 °C for 8 h. The mixture was then filtered, washed and dried to obtain a γ-FeOOH / S-1@MFI core-shell structure pore-gated desulfurization component with a Si / Al molar ratio of 100 (denoted as γ-FeOOH / S-1@MFI100).

[0065] The structure of this material is an S-1 core / γ-FeOOH continuous intermediate layer / Si / Al=100 high silicon MFI outer shell layer.

[0066] Examples 3 and 4 illustrate that even after introducing a very small amount of aluminum into the all-silicon S-1 outer shell layer, the pore structure of the high-silicon MFI gated layer can still be maintained, but its hydrophobicity and low CO2 affinity characteristics may be weaker than those of Example 2.

[0067] Example 5

[0068] The preparation steps of the composite desulfurization component confined in S-1 pores or intercrystalline micropores are as follows: (1) Take 5.00 g of S-1 molecular sieve nanorods and dry them under vacuum at 120℃ for 6 h; (2) Dissolve 1.20 g of Fe(NO3)3·9H2O in 15.0 mL of deionized water to obtain iron salt impregnation solution; add the iron salt impregnation solution into S-1 molecular sieve in an equal volume impregnation manner, let stand for 2 h and then dry at 60℃ for 6 h; (3) Place the dried sample in a sealed container, with 10 mL of 1.0 mol / L ammonia water at the bottom of the container. The sample should not come into direct contact with the ammonia water. Treat the sample with ammonia vapor at 60°C for 6 h to allow iron species to hydrolyze and deposit near the S-1 pore opening and intercrystalline micropores. Then age the sample in air at 80°C for 12 h to obtain a composite desulfurization component (denoted as γ-FeOOH-S-1) confined in the S-1 pore opening or intercrystalline micropores.

[0069] Example 6

[0070] The preparation steps of non-porous PDVB polymer powder are as follows: (1) Take 10.0 g of divinylbenzene, add 0.50 g of azobisisobutyronitrile, stir at 25℃ for 1 h to fully dissolve the initiator and obtain a mixture; (2) Transfer the mixture to a polytetrafluoroethylene-lined reactor and thermally polymerize it at 100°C for 24 h; (3) The obtained solid was washed three times with methanol and twice with ethanol, and then dried at 100°C for 12 h to obtain non-porous PDVB polymer powder; the obtained PDVB powder was ground and then sieved to obtain 40-60 mesh particles.

[0071] The PDVB powder does not act as a trapping phase for H2S reaction. Its function is to create a local hydrophobic microenvironment around the pore-gated desulfurization components, promoting water molecule desorption and reducing the entry of water molecules into the molecular sieve channels.

[0072] Example 7

[0073] The preparation steps of the γ-FeOOH / S-1@S-1 / PDVB physically blended water-resistant pore-gated composite material are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@S-1 core-shell structure pore-gated desulfurization component prepared in Example 2 and mix it with 0.50 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.10. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH / S-1@S-1 particles; then press, crush and sieve 40 to 60 mesh particles to obtain γ-FeOOH / S-1@S-1 / PDVB physical blend water-resistant pore-gated composite material (denoted as γ-FeOOH / S-1@S-1 / PDVB0.5).

[0074] Example 8

[0075] The preparation steps of the γ-FeO-S-1 / PDVB physically blended water-resistant, pore-gated composite material are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@S-1 core-shell structure pore-gated desulfurization component prepared in Example 2 and mix it with 0.25 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.05. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH / S-1@S-1 particles; then press, crush and sieve 40 to 60 mesh particles to obtain γ-FeOOH / S-1@S-1 / PDVB physical blend water-resistant pore-gated composite material (denoted as γ-FeOOH / S-1@S-1 / PDVB0.25).

[0076] Example 9

[0077] The preparation steps of the γ-FeOOH / S-1@S-1 / PDVB physically blended water-resistant pore-gated composite material are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@S-1 core-shell structure pore-gated desulfurization component prepared in Example 2 and mix it with 1.00 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.20. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH / S-1@S-1 particles; then press, crush and sieve 40 to 60 mesh particles to obtain γ-FeOOH / S-1@S-1 / PDVB physical blend water-resistant pore-gated composite material (denoted as γ-FeOOH / S-1@S-1 / PDVB1.0).

[0078] Examples 7-9 were used to investigate the effect of the content of blended PDVB powder on the composite material's resistance to CO2 / water interference.

[0079] Example 10

[0080] The preparation steps of the γ-FeOOH / S-1@high-silicon MFI / PDVB physically blended water-resistant pore-gated composite material with Si / Al=300 are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@high silicon MFI core-shell structure pore-gated desulfurization component prepared in Example 3 and mix it with 0.50 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.10. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH / S-1@high silicon MFI particles; then press, crush and sieve 40 to 60 mesh particles to obtain a γ-FeOOH / S-1@high silicon MFI / PDVB physical blend water-resistant pore-gated composite material with Si / Al=300 (denoted as γ-FeOOH / S-1@MFI300 / PDVB).

[0081] Example 11

[0082] The preparation steps of the γ-FeOOH / S-1@high-silicon MFI / PDVB physically blended water-resistant pore-gated composite material with Si / Al=100 are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@high silicon MFI core-shell structure pore-gated desulfurization component prepared in Example 4 and mix it with 0.50 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.10. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH / S-1@S-1 particles; then press, crush and sieve 40 to 60 mesh particles to obtain a γ-FeOOH / S-1@high silicon MFI / PDVB physical blend water-resistant pore-gated composite material with Si / Al=100 (denoted as γ-FeOOH / S-1@MFI100 / PDVB).

[0083] Examples 7 and 10-11 were used to investigate the effect of the Si / Al ratio on the hydrophobicity and resistance to CO2 / water interference of the gated layer.

[0084] Example 12

[0085] The preparation steps of the γ-FeOOH / S-1@S-1@PDVB surface hydrophobic treatment type water-resistant pore-gated composite material are as follows: (1) Take 5.00 g of the γ-FeOOH / S-1@S-1 core-shell structure pore-gated desulfurization component prepared in Example 2 and disperse it in 80 mL of n-hexane; (2) Take 0.15 g of divinylbenzene and 0.006 g of azobisisobutyronitrile, dissolve them in 10 mL of n-hexane, and then add the solution dropwise to the γ-FeOOH / S-1@S-1 dispersion; stir at 25 °C for 2 h under nitrogen protection, then raise the temperature to 75 °C and keep it for 8 h to allow divinylbenzene to undergo low-load in-situ polymerization on the outer surface of γ-FeOOH / S-1@S-1; (3) After the reaction is complete, filter the mixture, wash it twice with hexane and twice with ethanol, and dry it at 80℃ for 12 h to obtain the γ-FeOOH / S-1@S-1@PDVB surface hydrophobic treatment type water-resistant pore gated composite material (denoted as γ-FeOOH / S-1@S-1@PDVB).

[0086] In this embodiment, the amount of divinylbenzene fed is 3.0 wt% of the mass of the pore-gated desulfurization component, and the formed PDVB hydrophobic treatment layer is a discontinuous or dotted adhesion layer that does not completely block the pores of the S-1 outer shell layer.

[0087] Example 13

[0088] The preparation steps of the γ-FeOOH-S-1 / PDVB physically blended water-resistant pore-gated composite material are as follows: (1) Take 5.00 g of the γ-FeOOH-S-1 pore-gated desulfurization component prepared in Example 5 and mix it with 1.00 g of the non-porous PDVB polymer powder prepared in Example 6. The mass ratio of the pore-gated desulfurization component to PDVB is 1:0.20. (2) Grind the above solid in an agate mortar for 15 min to bring the PDVB powder into close contact with the γ-FeOOH-S-1 particles; then press, crush and sieve 40 to 60 mesh particles to obtain γ-FeOOH-S-1 / PDVB physical blend water-resistant pore-gated composite material (denoted as γ-FeOOH-S-1 / PDVB1.0).

[0089] Comparative Example 1 The preparation method of γ-FeOOH is as follows: Weigh 5.20 g of FeSO4·7H2O and add 10.0 mL of 0.10 mol / L EDTA aqueous solution; under strong stirring, add 1.0 mol / L dilute ammonia water dropwise to adjust the pH of the system to 8.0, and then oxidize in air atmosphere for 1 h; then adjust the pH to 8.0 again with 1.0 mol / L dilute ammonia water, and continue aging for 2 h to obtain γ-FeOOH powder.

[0090] Comparative Example 2 Take 0.25 g of γ-FeOOH powder prepared in Comparative Example 1 and 0.75 g of S-1 molecular sieve nanorods, grind them in an agate mortar for 15 min to obtain a physical mixture of γ-FeOOH and S-1 (denoted as γ-FeOOH+S-1).

[0091] To investigate the role of water-resistant channel-gated composite materials in deep desulfurization and protecting the catalyst for carbon dioxide hydrogenation to olefins, the following application examples were set up.

[0092] Application Example 1 Water-resistant, gated composite materials were used for the selective removal of H2S and / or COS in CO2-enriched atmospheres. Depth desulfurization measurements were performed under the following different CO2-enriched atmospheres: Test 1 (Effect of pore-gated desulfurization components and hydrophobic polymer components on desulfurization efficiency): The gas tested was the feedstock gas for carbon dioxide hydrogenation to olefins. The hydrogen in the carbon dioxide feedstock gas comes from water electrolysis. After condensation and drying, the gas still contains trace amounts of water vapor and 1000 ppm of H2O. The typical composition of the carbon dioxide product gas is shown in Table 1. This gas is characterized by high CO2, low H2, trace amounts of H2S, trace amounts of COS, and contains methanol and low-carbon hydrocarbon impurities, representing the complex atmosphere that needs to be treated in the deep purification of feedstock gas for carbon dioxide hydrogenation to olefins.

[0093] Table 1. Typical carbon dioxide product gas composition

[0094] This application example will determine the desulfurization effect of γ-FeOOH (Comparative Example 1), γ-FeOOH+S-1 (Comparative Example 2), γ-FeOOH / S-1@S-1 (Example 2), γ-FeOOH / S-1@S-1 / PDVB0.5 (Example 7), γ-FeOOH / S-1@S-1@PDVB (Example 12), and γ-FeOOH-S-1 / PDVB1.0 (Example 13). After sieving 40-60 mesh particles, 0.70 g of each was weighed and packed into a 6 mm inner diameter stainless steel fixed-bed desulfurization tube. Both ends of the bed were fixed with quartz wool. The desulfurization bed was placed before the carbon dioxide hydrogenation to olefins reactor. The desulfurization bed operating temperature was 25℃, the pressure was 0.10 MPa, and the total gas flow rate was 50 mL / min. The outlet H2S concentration was monitored online, and the breakthrough time was recorded when the outlet H2S reached 0.1 ppm. The breakthrough time in Table 2 represents the test results.

[0095] Table 2. Evaluation results of desulfurization of different materials in feedstock gas for carbon dioxide hydrogenation to olefins.

[0096] As shown in Table 2, when γ-FeOOH is used alone, its adsorption sites are directly exposed and easily affected by CO2 and water vapor. When γ-FeOOH is physically mixed with S-1, although the influence of CO2 or water can be partially reduced, the molecular sieve still cannot fully protect the surface of γ-FeOOH. Ultimately, the breakthrough time of both is only 1 h, and the dynamic sulfur capacity is only 0.056 mg S·g. -1 In contrast, the γ-FeOOH / S-1@S-1 composite material, with its core-shell structure and gated desulfurization components, allows the H2S adsorption sites of γ-FeOOH to be located behind the high-silica MFI molecular sieve gate layer, protecting the γ-FeOOH sites, limiting direct contact, extending the breakthrough time to 20 h, and correspondingly increasing the dynamic sulfur capacity to 1.124 mg S·g. -1Based on the γ-FeOOH / S-1@S-1 channel-gated desulfurization component, further introduction of hydrophobic polymer components (PDVB blend or surface hydrophobic treatment) creates a locally hydrophobic microenvironment. Water molecules are less likely to enter the molecular sieve channels, further reducing the occupancy of active sites. This extends the breakthrough time to 316 h and 487 h, respectively, and increases the dynamic sulfur capacity to 17.761 mg S·g. -1 and 27.372 mg S·g -1 Furthermore, the blending of the pore-gated desulfurization component γ-FeOOH-S-1 with a confined structure and the hydrophobic polymer PDVB also resulted in a longer breakthrough time of 138 h compared to γ-FeOOH / S-1@S-1 containing only the desulfurization component, with a corresponding increase in dynamic sulfur capacity to 7.728 mg S·g. -1 .

[0097] Test 2 (Effect of the mass ratio of hydrophobic polymer components on desulfurization efficiency): The test gas composition was 10 ppm H2S, 60 vol% CO2, 1000 ppm H2O, with N2 as the equilibrium gas. The total flow rate was 50 mL / min, the temperature was 25 °C, and the pressure was 0.10 MPa. 0.70 g each of the water-resistant, pore-gated composite materials γ-FeOOH / S-1@S-1 / PVDB0.5, γ-FeOOH / S-1@S-1 / PVDB0.25, and γ-FeOOH / S-1@S-1 / PVDB1.0 prepared in Examples 7-9 were used for fixed-bed testing. This was used to determine the effect of the mass ratio of hydrophobic polymer components on the H2S penetration behavior in a water-containing CO2 atmosphere.

[0098] The breakthrough times of the γ-FeOOH / S-1@S-1 / PVDB0.25, γ-FeOOH / S-1@S-1 / PVDB0.5, and γ-FeOOH / S-1@S-1 / PVDB1.0 samples were determined to be 285 h, 313 h, and 265 h, respectively, with a dynamic sulfur capacity of 15.96 mg S·g. -1 17.528 mg S·g -1 and 14.84 mg S·g -1 .

[0099] It is evident that as the mass ratio of γ-FeOOH / S-1@S-1 to PDVB polymer powder in the composite material increases from 1:0.05 to 1:0.10, the breakthrough time and dynamic sulfur capacity are significantly improved. This is because an appropriate amount of hydrophobic component forms a more effective hydrophobic microenvironment around the γ-FeOOH / S-1@S-1 particles, reducing the competition of water vapor for the molecular sieve channels and γ-FeOOH adsorption sites, thereby prolonging the effective collection time of H2S. However, when the ratio is further increased to 1:0.20, excessive PDVB powder may agglomerate and partially block the molecular sieve pores or cover the surface of the desulfurization components, increasing the mass transfer resistance of H2S to the γ-FeOOH reaction trapping phase. At the same time, it may weaken the sieve gating effect, resulting in a decrease in breakthrough time and sulfur capacity, indicating that there is an optimal range of hydrophobic polymer addition.

[0100] Test 3 (The effect of the Si / Al ratio of the high-silicon MFI molecular sieve gate layer on desulfurization efficiency): The test gas composition consisted of the gas listed in Table 1 containing 1000 ppm H2O, with N2 as the equilibrium gas. The total flow rate was 50 mL / min, the temperature was 25℃, and the pressure was 0.10 MPa. 0.70 g each of the pore-gated composite materials γ-FeOOH / S-1@S-1 / PDVB0.5, γ-FeOOH / S-1@MFI300 / PDVB, and γ-FeOOH / S-1@MFI100 / PDVB from Examples 7, 10, and 11 were packed into fixed-bed quartz tubes. The high-silica MFI molecular sieve gating layers corresponding to the three groups of samples were all-silica S-1, high-silica MFI with Si / Al=300, and high-silica MFI with Si / Al=100, respectively. This test was used to determine the effect of the Si / Al ratio of the high-silica MFI molecular sieve gating layer on the interference of CO2 and water vapor.

[0101] The breakthrough times of the channel-gated composite materials γ-FeOOH / S-1@S-1 / PDVB0.5, γ-FeOOH / S-1@MFI300 / PDVB, and γ-FeOOH / S-1@MFI100 / PDVB were measured to be 487 h, 325 h, and 289 h, respectively, with a dynamic sulfur capacity of 27.272 mg S·g. -1 18.200 mg S·g -1 and 16.184 mg S·g -1 .

[0102] It is evident that as the Si / Al ratio in the gated layer decreases (i.e., the aluminum content increases), the molecular sieve framework introduces more aluminum atoms, accompanied by balancing cations, significantly enhancing its hydrophilicity. In a test atmosphere containing 1000 ppm water, the MFI channels with higher aluminum content exhibit stronger adsorption affinity for water molecules. Water molecules not only occupy the pore space and form diffusion barriers, hindering the effective mass transfer of H2S to the γ-FeOOH reaction trapping phase, but also compete with H2S for active adsorption sites on the γ-FeOOH surface, leading to a decrease in trapping efficiency. In contrast, the all-silicon S-1 framework contains almost no aluminum and possesses intrinsic hydrophobic properties, exhibiting extremely low affinity for water vapor. This minimizes the competitive adsorption and occupation of water molecules within the pores, ensuring that H2S preferentially passes through the gated layer to reach the internal reaction sites. Therefore, as the Si / Al ratio increases from 100 to 300 and eventually to all-silicon, water interference is gradually weakened, the breakthrough time increases from 289 h to 325 h and 487 h, and the dynamic sulfur capacity increases from 16.184 mg S·g. -1 Increased to 18.200 mg S·g -1 and 27.272 mg S·g -1 This fully demonstrates that the all-silicon S-1 gated layer can most effectively meet the dual requirements of "hydrophobicity and water resistance" and "H2S mass transfer" in a water-containing CO2 atmosphere, and is the optimal structure in this invention.

[0103] Test 4 (The effect of simple reaction trapping on desulfurization efficiency): 0.70 g of the γ-FeOOH / S-1 desulfurization component prepared in Example 1 was sieved to obtain particles of 40 to 60 mesh and packed into a fixed-bed quartz tube with an inner diameter of 6 mm. The first group of test gases consisted of 10 ppm H2S and Ar as the balance gas; the second group of test gases consisted of 10 ppm H2S, 60 vol% CO2, and N2 as the balance gas. The total flow rate for both groups of tests was 50 mL / min, the temperature was 25°C, and the pressure was 0.10 MPa.

[0104] The breakthrough time of this sample in the first group was determined to be 367 h, and the dynamic sulfur capacity was 20.552 mg S·g. -1 In the second group, the breakthrough time was 1 h and the dynamic sulfur capacity was 0.056 mg S·g. -1The main reason is that no competitive adsorption occurs in an Ar atmosphere, and H2S can be completely captured by γ-FeOOH sites, resulting in a breakthrough time of up to 367 h. However, in a CO2 atmosphere, although CO2 has no permanent dipole moment, it has a quadrupole moment and its concentration is much higher than that of H2S. This can lead to weak competition for hydroxyl groups on the surface of γ-FeOOH or sites near the pore entrance, thus potentially resulting in a small amount of initial H2S breakthrough, ultimately leading to a breakthrough time of only 1 h. In the γ-FeOOH / S-1 desulfurization component prepared in Example 1, γ-FeOOH is mainly loaded on the outer surface of the S-1 molecular sieve. According to the test results, γ-FeOOH cannot completely desulfurize under this structure, meaning that the simple γ-FeOOH reaction trapping phase is affected by CO2 and cannot exert a good deep desulfurization effect.

[0105] Combined with the measurement results in Table 2 above, it can be seen that the present invention designs core-shell structured pore-gated desulfurization components based on the γ-FeOOH / S-1 desulfurization component, such as γ-FeOOH / S-1@S-1, γ-FeOOH / S-1@MFI300 and γ-FeOOH / S-1@MFI100 (Examples 2~4); or designs confined structured pore-gated desulfurization components, such as γ-FeOOH-S-1 (Example 5), all of which have better desulfurization effects than γ-FeOOH or a physical mixture of γ-FeOOH and S-1.

[0106] Application Example 2 Water-resistant pore-gated composite materials are used for catalyst protection in the carbon dioxide hydrogenation to olefins process. The effect of packing the water-resistant pore-gated composite material into a pre-desulfurization bed on the subsequent carbon dioxide hydrogenation to olefins catalyst was determined.

[0107] Two 2.00 g portions of the core-shell structured pore-gated desulfurization component γ-FeOOH / S-1@S-1 and the water-resistant pore-gated composite material γ-FeOOH / S-1@S-1@PVDB prepared in Examples 2 and 12 were respectively packed into a pre-desulfurization bed. One 1.00 g portion of a carbon dioxide hydrogenation to olefins catalyst (prepared according to Example 1 of patent CN118976513B) was connected in series at the rear end. The gas composition entering the pre-desulfurization bed was as shown in Table 1, the total flow rate was 50 mL / min, the desulfurization bed temperature was 25℃, and the pressure was 0.10 MPa. After treatment in the pre-desulfurization bed, the outlet H2S was controlled below 0.1 ppm before entering the carbon dioxide hydrogenation to olefins catalyst bed. The CO2 conversion rate test results for carbon dioxide hydrogenation to olefins are shown in […]. Figure 1 .

[0108] Measurements showed that after treatment with the water-resistant pore-gated composite material γ-FeOOH / S-1@S-1@PVDB pre-desulfurization bed, the CO2 conversion rate of the carbon dioxide hydrogenation to olefins catalyst remained stable for 80 h without any decrease; however, when treated with the pore-gated desulfurization component γ-FeOOH / S-1@S-1, the CO2 conversion rate of the catalyst began to decrease significantly after 60 h. This indicates that the pore-gated desulfurization component and the hydrophobic polymer component of the water-resistant pore-gated composite material have a dual function, exerting a good deep adsorption desulfurization effect and maintaining the H2S concentration below 0.1 ppm for a long time. This protects the catalyst for carbon dioxide hydrogenation to olefins and can be used to reduce the risk of interface poisoning of metal oxides, molecular sieves and metal oxide-molecular sieve composites by H2S and COS. In contrast, γ-FeOOH / S-1@S-1, which only contains the desulfurization component, initially exerts a good desulfurization effect. However, as time goes on, due to the lack of hydrophobic polymer components, the active sites are gradually occupied by water molecules, the desulfurization effect gradually decreases, and eventually the catalyst interface is poisoned and fails.

Claims

1. A water-resistant, channel-gated composite material, characterized in that, The system comprises a pore-gated desulfurization component and a hydrophobic polymer component. The pore-gated desulfurization component includes a γ-FeOOH reaction trapping phase and a high-silica MFI molecular sieve gated layer located outside the γ-FeOOH reaction trapping phase. The hydrophobic polymer component is one or more of the following: polyvinylbenzene polymer powder physically blended with the pore-gated desulfurization component, polyvinylbenzene polymer particles physically blended with the pore-gated desulfurization component, and a polymer hydrophobic treatment layer located on the outer surface of the pore-gated desulfurization component. The high-silica MFI molecular sieve gated layer is a Silicalite-1 molecular sieve layer or an MFI molecular sieve layer with a Si / Al molar ratio of not less than 100. The mass ratio of the pore-gated desulfurization component to the polyvinylbenzene polymer particles or polyvinylbenzene polymer powder is 1:0.05~0.

2.

2. The water-resistant channel-gated composite material according to claim 1, characterized in that, The pore-gated desulfurization component is a core-shell structured particle, wherein the γ-FeOOH reaction trapping phase is the core and the high-silica MFI molecular sieve gate layer is the outer shell; the γ-FeOOH reaction trapping phase is γ-FeOOH supported on the high-silica MFI molecular sieve.

3. The water-resistant channel-gated composite material according to claim 1, characterized in that, The polyvinylbenzene polymer powder or polyvinylbenzene polymer particles are one or more of nonporous polyvinylbenzene, microporous polyvinylbenzene, and mesoporous polyvinylbenzene; the polymer hydrophobic treatment layer includes one or more of the following: polyvinylbenzene layer, in-situ polymerized divinylbenzene layer, polystyrene layer, polytetrafluoroethylene layer, polyolefin layer, fluoropolymer layer, and hydrophobic organosilicon polymer layer.

4. A method for preparing a water-resistant, channel-gated composite material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Preparation of the γ-FeOOH reaction trapping phase; S2. A high-silica MFI molecular sieve gated layer is formed on the outside of the γ-FeOOH reaction trapping phase to obtain a pore-gated desulfurization component; S3. Physically blend the pore-gated desulfurization component with polyvinylbenzene polymer powder or polyvinylbenzene polymer particles, and / or perform hydrophobic treatment on the outer surface of the pore-gated desulfurization component to form a polymer hydrophobic treatment layer, thereby obtaining a water-resistant pore-gated composite material.

5. The preparation method according to claim 4, characterized in that, In step S1, the γ-FeOOH reaction trapping phase is obtained by iron salt hydrolysis, precipitation oxidation, hydrothermal conversion or air oxidation; the iron salt is selected from one or more of ferric nitrate, ferric chloride, ferric sulfate, ferric acetate and ferric oxalate.

6. The preparation method according to claim 4, characterized in that, In step S2, the high-silicon MFI molecular sieve gated layer is formed by seed-assisted growth, in-situ crystallization, secondary growth, molecular sieve nanocrystal assembly, molecular sieve sol deposition, or a combination thereof.

7. The preparation method according to claim 4, characterized in that, In step S3, the polymer hydrophobic treatment layer is a discontinuous layer, an island-shaped distribution layer, a dotted adhesion layer, a thin film layer, or a porous coating layer, with a thickness of 5~50 nm.

8. The preparation method according to claim 4 or 7, characterized in that, In step S3, the hydrophobic treatment is as follows: the pore-gated desulfurization component is contacted with a treatment liquid containing divinylbenzene, an initiator, and a solvent for in-situ polymerization to obtain a pore-gated desulfurization component with a hydrophobic surface; or, the pore-gated desulfurization component is contacted with a polyvinylbenzene dispersion, a polystyrene dispersion, a polytetrafluoroethylene dispersion, a polyolefin dispersion, a fluoropolymer dispersion, or a hydrophobic organosilicon polymer dispersion, and then subjected to impregnation, stirring, spraying, filtration, drying, or curing treatment to obtain a pore-gated desulfurization component with a hydrophobic surface.

9. An application of a water-resistant channel-gated composite material according to any one of claims 1 to 3, characterized in that it is used for Selective removal of H2S and / or COS in a CO2-enriched atmosphere; or for catalyst protection in the process of carbon dioxide hydrogenation to olefins.

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