Desulfurizing agent, preparation method therefor and use thereof in flue gas desulfurization

Abstract

Provided in the present invention are a desulfurizing agent, a preparation method therefor and the use thereof in flue gas desulfurization. The preparation method comprises: mixing a mixed solution A containing a magnesium salt, an aluminum salt and a precipitant and a mixed solution B containing a Gemini anionic surfactant, carrying out a hydrothermal reaction, and sequentially performing washing, drying, grinding, primary roasting, forming and secondary roasting on a precipitate obtained from the hydrothermal reaction, so as to obtain the desulfurizing agent having relatively high desulfurization activity.

Description

Desulfurizer, preparation method thereof and application in flue gas desulfurization

[0001] Cross-reference information

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on December 28, 2023, with application number 202311838306.X and invention name “Desulfurizer, preparation method thereof and application in flue gas desulfurization”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The invention belongs to the technical field of chemical environmental protection, and relates to a desulfurizing agent, a preparation method thereof, and application in flue gas desulfurization. Background Art

[0004] SO2 is a colorless, acidic gas with a strong, pungent odor. Its large-scale emission poses serious risks to humans and the ecological environment. SO2, a common atmospheric pollutant, primarily originates from flue gas produced by the combustion of fossil fuels. To reduce SO2 emissions, various flue gas treatment technologies have been proposed, categorized by their process characteristics into wet, dry, and semi-dry flue gas desulfurization. Wet flue gas desulfurization is mature and widely used, but its system complexity, bulky equipment, high investment and operating costs, and the risk of secondary pollution. Compared to wet flue gas desulfurization, dry flue gas desulfurization offers advantages such as a smaller footprint, simpler equipment operation, and lower costs. Since its introduction, it has garnered widespread attention. Dry flue gas desulfurization involves the catalytic conversion of SO2 in flue gas into metal sulfates or sulfites using a desulfurizer, which then fixes the metals and effectively reduces the concentration of sulfur oxides in the exhaust gas. Desulfurizers are generally classified as renewable or non-renewable. Among them, the regenerable desulfurizer refers to a desulfurizer that catalyzes the conversion of sulfur in metal sulfates or sulfites into SO2, H2S or S elemental substances under the action of reducing gas, thereby restoring the initial reaction activity of the desulfurizer.

[0005] Available renewable desulfurizers primarily include metal oxides, spinels, and composite metal oxides derived from hydrotalcite compounds. Metal-based catalysts, including transition metals, noble metals, and non-noble metals, exhibit excellent structural tunability, abundant Lewis acid active sites, and high activity stability, resulting in excellent catalytic reduction activity. However, these adsorbents are difficult to reduce and have low sulfur capacity. Spinel-based desulfurizers are currently the primary type of commercial desulfurization adsorbent due to their simple preparation process, good desulfurization effectiveness, and mature technology. However, these desulfurizers contain low Mg content, making bulk sulfate difficult to regenerate and reduce, resulting in unstable activity. Summary of the Invention

[0006] In order to improve the above problems, according to one aspect of the present invention, a desulfurizer is provided. The desulfurizer is a composite metal oxide. The metal elements in the composite metal oxide include magnesium and aluminum. The specific surface area of ​​the desulfurizer is ≥180m 2 / g. The desulfurizer has a large specific surface area, which improves the dispersion of active metals in the desulfurizer, fully exerts the synergistic catalytic effect between the metals, increases the sulfur capacity and reduction reaction activity of the adsorbent, and achieves the beneficial effect of significantly improving the desulfurization catalytic activity.

[0007] Furthermore, the specific surface area of ​​the desulfurizer is 184 to 219 m 2 / g, pore size is 16~21nm.

[0008] Furthermore, the metal elements in the composite metal oxide also include cerium.

[0009] Furthermore, the desulfurizer has the structural formula A a B b C c O x , where A is Mg, B is Al, C is Ce, a:b:c is 2:1.7~7.29:0.1~0.5, and the value of x makes the desulfurizer satisfy the positive and negative valence balance.

[0010] Furthermore, the desulfurizer has a 3D spherical morphology (formed by the aggregation of hexagonal nanosheets) with a specification of The crushing strength is ≥169N / cm, and the sulfur capacity can reach 0.24gSO2 / gcat.

[0011] According to another aspect of the present invention, a method for preparing a desulfurizer is provided, comprising: mixing a mixed solution A comprising a magnesium salt, an aluminum salt, and a precipitant with a mixed solution B comprising a gemini anionic surfactant having a molar concentration of 0.1 to 0.5 mol / L, followed by a hydrothermal reaction; and sequentially washing, drying, grinding, primary calcination, molding, and secondary calcination of a precipitate obtained by the hydrothermal reaction to obtain a desulfurizer; the gemini anionic surfactant having a structure shown in Formula I:

[0012] In formula I, 10≤n≤16, 2≤m≤6, and n and m are both integers.

[0013] Hydrotalcite compounds (LDHs) belong to the hexagonal crystal system, with two-dimensional layers arranged in three dimensions. The desulfurization performance of composite metal oxide desulfurizers is closely related to the structure and morphology of the uncalcined hydrotalcite compound (LDH) crystals. The present invention utilizes the gemini anionic surfactant shown in the above structure to effectively control the growth of hydrotalcite compound crystals during crystallization. Ultimately, after calcination, composite metal oxide crystals with a 3D spherical morphology (formed by aggregation of hexagonal nanosheets), high crystallinity, and a large specific surface area are obtained. This improves the dispersion of the active metals in the desulfurizer, fully utilizes the synergistic catalytic effect between the metals, increases the sulfur capacity and reduction reaction activity of the adsorbent, and achieves the beneficial effect of significantly improving the desulfurization catalytic activity.

[0014] Among them, in the initial reaction system of hydrotalcite compounds, when the concentration of the gemini anionic surfactant is greater than the critical micelle concentration, the surfactant in the solution aggregates to form spherical micelles, in which the hydrophobic tail groups are inward and the hydrophilic head groups are outward. Due to the strong electrostatic attraction between the anionic surfactant and the hydrotalcite lamellae, it can be embedded between the hydrotalcite lamellae through anion exchange, thereby significantly increasing the interlayer distance. At the same time, the present invention also effectively regulates the increase in interlayer distance by controlling the number of carbon atoms in the hydrophobic end alkyl chain. The negatively charged anions at the head generate a strong attraction with the metal cations in the solution, causing crystals to grow along the interface of the spherical micelles and aggregate to form a 3D spherical morphology.

[0015] Furthermore, the present invention utilizes a Gemini anionic surfactant modified with a hydrotalcite-like compound as shown in the above structure to produce hydrotalcite-like compound crystals in a one-step process without the addition of organic solvents. This method is simple to operate and environmentally friendly, with promising prospects for industrial application. Furthermore, the resulting desulfurizer can be subsequently regenerated through simple treatment, improving its usability.

[0016] It is further supplemented that the above-mentioned Gemini anionic surfactants of the present application can be directly purchased commercially, or can be prepared by referring to existing literature. The synthesis route is as follows:

[0017] In an optional embodiment, the specific synthesis steps are as follows: take H2NC m H 2mNH₂ is dissolved in ethanol, then vigorously stirred and the corresponding alkane-substituted n-alkanes are added dropwise. The reaction is continued at 70–90°C for 45–50 h. After completion of the reaction, the solvent is removed by vacuum rotary evaporation to yield a pale yellow powdery solid. The solid is then washed with ether until white and recrystallized two to three times from a 2:1 (volume ratio) methanol-chloroform mixture to yield a white needle-like solid. The white needle-like solid, 1,3-propane sultone, and sodium hydroxide are dissolved in methanol and refluxed at 60–65°C under a nitrogen atmosphere for 20–30 h. The mixture is then evaporated to dryness on a vacuum rotary evaporator to yield a white solid. Column chromatography is performed using a mixture of chloroform and petroleum ether as the eluent. The desired fraction is collected and evaporated to dryness on a vacuum rotary evaporator to yield a white solid powder. This is then recrystallized two to three times from methanol-chloroform to yield a white powdery product, the corresponding gemini anionic surfactant.

[0018] In some optional embodiments, the solvents of the mixed solution A and the mixed solution B can each independently be water. Gemini anionic surfactants include but are not limited to one or more selected from the following compounds:

[0019] Furthermore, the precipitant is selected from one or more of urea, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. In the mixed solution A, the molar concentration of the precipitant is 8 to 12 mol / L.

[0020] Furthermore, the raw materials forming mixed solution A also include cerium salts; the total molar concentration of magnesium, aluminum, and cerium in mixed solution A is 0.8 to 1.2 mol / L; and the molar ratio of magnesium, aluminum, and cerium in mixed solution A is 2:0.5 to 1:0.1 to 0.5. In some optional embodiments, the magnesium salt, aluminum salt, and cerium salt include, but are not limited to, one or more of sulfates, chlorides, nitrates, and acetates of the corresponding metal elements.

[0021] In a preferred embodiment, after the primary calcination and before molding, the preparation method further comprises the step of mixing the primary calcined product with a binder and a pore-enlarging agent to form a mixed system C. The binder is selected from one or more of alumina sol, high-temperature cement, and pseudo-boehmite. In mixed system C, the pore-enlarging agent comprises 1 to 5 wt % of the pore-enlarging agent. The pore-enlarging agent is selected from one or more of sesbania powder, carboxymethyl cellulose, starch, and hexadecyltrimethylammonium bromide. The weight ratio of the binder to the primary calcined product is 1:1 to 3. In some optional embodiments, molding includes, but is not limited to, extrusion molding.

[0022] Preferably, the hydrothermal reaction temperature is 140-180°C and the time is 8-16 hours. Preferably, the primary and secondary calcinations are each independently calcined at a temperature of 450-600°C and each independently calcined for a time of 5-12 hours. Preferably, the drying temperature is 60-90°C. Preferably, the particle size of the ground material is 300-500 mesh.

[0023] According to another aspect of the present invention, a desulfurizing agent is provided, which is prepared by the above-mentioned method for preparing a desulfurizing agent. Based on the above reasons, the desulfurizing agent of the present invention has excellent desulfurization catalytic activity.

[0024] According to another aspect of the present invention, a use of the aforementioned desulfurizer in flue gas desulfurization is provided. Based on the above reasons, the desulfurizer of the present invention exhibits excellent catalytic reduction reaction activity when used in flue gas desulfurization, has high sulfur capacity, and is easy to reduce and regenerate.

[0025] In an optional embodiment, the volume concentration of SO2 in the flue gas to be treated is 0.1-2%, and the temperature during flue gas treatment is 400-600°C. After flue gas desulfurization, the desulfurizer can be reduced and regenerated using H2 / N2 at a temperature of 400-600°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is an XRD spectrum of the hydrotalcite compound powder in Example 3;

[0027] FIG2 is an XRD spectrum of the composite metal oxide desulfurizer in Example 3;

[0028] FIG3 is a SEM image of the hydrotalcite compound powder in Example 3;

[0029] FIG4 is a SEM image of the hydrotalcite compound powder in Example 3;

[0030] FIG5 is a SEM spectrum of the composite metal oxide desulfurizer in Example 3;

[0031] FIG6 is a diagram showing the N2 physical adsorption-desorption isotherm and pore size distribution of the composite metal oxide desulfurizer in Example 3. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0033] Source of raw materials:

[0034] A series of gemini anionic surfactants were synthesized with reference to existing literature:

[0035] Cn H 2n+1 NC2H4NC n H 2n+1 Synthesis and purification of (n is an integer, 10 ≤ n ≤ 16): Dissolve 0.1 mol of ethylenediamine in 200 mL of ethanol. Then, vigorously stir and dropwise add 0.25 mol of the corresponding alkane-substituted n-alkane. The mixture is allowed to react at 80°C for 48 hours. After completion, the solvent is removed by rotary evaporation under vacuum to yield a pale yellow powdery solid. The product is then washed with ether until white and recrystallized two to three times from a 2:1 (volume ratio) methanol-chloroform mixture to yield a white, needle-like solid.

[0036] Accordingly, ethylenediamine is replaced by propylenediamine and hexamethylenediamine in equal molar amounts, and the other steps above remain unchanged to synthesize C n H 2n+1 NC3H6NC n H 2n+1 , C n H 2n+1 NC6H 12 NC n H 2n+1 , 10≤n≤16, and n is an integer.

[0037] Synthesis and purification of Gemini anionic surfactant: 0.02 mol of the above-mentioned intermediate product C n H 2n+1 NC2H4NC n H 2n+1 (n is an integer, and 10≤n≤16) and 0.11 mol of 1,3-propane sultone and 0.11 mol of sodium hydroxide are dissolved in 250 mL of methanol, and refluxed at 333 K in a nitrogen atmosphere for 24 hours. Then, the mixture is evaporated to dryness in a vacuum rotary evaporator to obtain a white solid. Column chromatography is performed using chloroform-petroleum ether as an eluent, and the solution of the desired component is collected and evaporated to dryness in a vacuum rotary evaporator to obtain a white solid powder. The product is recrystallized 2 to 3 times with methanol and chloroform to obtain a white powdery product.

[0038] C n H 2n+1 NC3H6NC n H 2n+1 , C n H 2n+1 NC6H 12 NC n H 2n+1 The intermediates are operated accordingly, and the following compounds are synthesized in sequence according to the different intermediate products:

[0039] The solvent of the mixed solution A and the mixed solution B is deionized water.

[0040] Example 1

[0041] This embodiment provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0042] (1) Preparation of hydrotalcite compounds

[0043] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0044] 250 mL of an aqueous solution of a gemini anionic surfactant M was prepared and recorded as mixed solution B. The concentration of the gemini anionic surfactant M was 0.2 mol / L.

[0045] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0046] (2) Preparation of composite metal oxide desulfurizer

[0047] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0048] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S1Mg2Al 1.90 Ce 0.12 O 5.03 .

[0049] Example 2

[0050] This embodiment provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0051] (1) Preparation of hydrotalcite compounds

[0052] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate and urea, recorded as mixed solution A, wherein the concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0053] 250 mL of an aqueous solution of a gemini anionic surfactant K was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant K was 0.2 mol / L.

[0054] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0055] (2) Preparation of composite metal oxide desulfurizer

[0056] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0057] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S2Mg2Al 1.90 Ce 0.12 O 5.03 .

[0058] Example 3

[0059] This embodiment provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0060] (1) Preparation of hydrotalcite compounds

[0061] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0062] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.2 mol / L.

[0063] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0064] (2) Preparation of composite metal oxide desulfurizer

[0065] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0066] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S3Mg2Al 1.90 Ce 0.12 O 5.03 .

[0067] Figure 1 is the XRD spectrum of the hydrotalcite compound powder in Example 3; Figure 2 is the XRD spectrum of the composite metal oxide desulfurizer in Example 3; Figure 3 is the SEM image of the hydrotalcite compound powder in Example 3; Figure 4 is the SEM image of the hydrotalcite compound powder in Example 3; Figure 5 is the SEM image of the composite metal oxide desulfurizer in Example 3; Figure 6 is the N2 physical adsorption-desorption isotherm and pore size distribution diagram of the composite metal oxide desulfurizer in Example 3.

[0068] Example 4

[0069] (1) Preparation of hydrotalcite compounds

[0070] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0071] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.1 mol / L.

[0072] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0073] (2) Preparation of composite metal oxide desulfurizer

[0074] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0075] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S4Mg2Al 1.90 Ce 0.12 O 5.03 .

[0076] Example 5

[0077] (1) Preparation of hydrotalcite compounds

[0078] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0079] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.5 mol / L.

[0080] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0081] (2) Preparation of composite metal oxide desulfurizer

[0082] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0083] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S5Mg2Al 1.90 Ce 0.12 O 5.03 .

[0084] Example 6

[0085] (1) Preparation of hydrotalcite compounds

[0086] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0087] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.2 mol / L.

[0088] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0089] (2) Preparation of composite metal oxide desulfurizer

[0090] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 450° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0091] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S6Mg2Al 1.90 Ce 0.12 O 5.03 .

[0092] Example 7

[0093] (1) Preparation of hydrotalcite compounds

[0094] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0095] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.2 mol / L.

[0096] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0097] (2) Preparation of composite metal oxide desulfurizer

[0098] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 600° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0099] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S7Mg2Al 1.90 Ce 0.12 O 5.03 .

[0100] Example 8

[0101] (1) Preparation of hydrotalcite compounds

[0102] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0103] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.2 mol / L.

[0104] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 140°C for 12 h under a nitrogen atmosphere. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0105] (2) Preparation of composite metal oxide desulfurizer

[0106] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0107] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S8Mg2Al 1.90 Ce 0.12 O 5.03 .

[0108] Example 9

[0109] (1) Preparation of hydrotalcite compounds

[0110] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0111] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.2 mol / L.

[0112] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 180°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0113] (2) Preparation of composite metal oxide desulfurizer

[0114] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0115] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S9Mg2Al 1.90 Ce 0.12 O 5.03 .

[0116] Example 10

[0117] (1) Preparation of hydrotalcite compounds

[0118] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 8 mol / L.

[0119] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.1 mol / L.

[0120] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0121] (2) Preparation of composite metal oxide desulfurizer

[0122] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0123] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S10Mg2Al1.90 Ce 0.12 O 5.03 .

[0124] Example 11

[0125] (1) Preparation of hydrotalcite compounds

[0126] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 12 mol / L.

[0127] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.5 mol / L.

[0128] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0129] (2) Preparation of composite metal oxide desulfurizer

[0130] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0131] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S11Mg2Al 1.90 Ce 0.12 O 5.03 .

[0132] Example 12

[0133] (1) Preparation of hydrotalcite compounds

[0134] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0135] 250 mL of an aqueous solution of a gemini anionic surfactant Q was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant Q was 0.2 mol / L.

[0136] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0137] (2) Preparation of composite metal oxide desulfurizer

[0138] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0139] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into a mold, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S12Mg2Al 1.90 Ce 0.12 O 5.03 .

[0140] Comparative Example 1

[0141] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0142] (1) Preparation of hydrotalcite compounds

[0143] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0144] Mixed solution A and 250 mL of deionized water were transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C for 12 hours. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0145] (2) Preparation of composite metal oxide desulfurizer

[0146] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0147] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer D1.

[0148] Comparative Example 2

[0149] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0150] (1) Preparation of hydrotalcite compounds

[0151] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0152] 250 mL of a mixed solution of dodecyl sulfonate anionic surfactant was prepared, which was recorded as mixed solution B, wherein the concentration of the anionic surfactant was 0.2 mol / L.

[0153] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0154] (2) Preparation of composite metal oxide desulfurizer

[0155] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0156] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer D2.

[0157] Comparative Example 3

[0158] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0159] (1) Preparation of hydrotalcite compounds

[0160] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0161] Prepare 250 mL of an aqueous solution of a geminisulfonate anionic surfactant, referred to as mixed solution B, wherein the structural formula of the geminisulfonate anionic surfactant is The concentration is 0.2mol / L.

[0162] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (greater than 300 mesh), i.e., a hydrotalcite-like compound powder.

[0163] (2) Preparation of composite metal oxide desulfurizer

[0164] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0165] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer D3.

[0166] Comparative Example 4

[0167] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0168] (1) Preparation of hydrotalcite compounds

[0169] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0170] Prepare 250 mL of an aqueous solution of a geminisulfonate anionic surfactant, referred to as mixed solution B, wherein the structural formula of the geminisulfonate anionic surfactant is The concentration is 0.2mol / L.

[0171] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (greater than 300 mesh), i.e., a hydrotalcite-like compound powder.

[0172] (2) Preparation of composite metal oxide desulfurizer

[0173] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0174] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer D4.

[0175] Comparative Example 5

[0176] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0177] (1) Preparation of hydrotalcite compounds

[0178] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0179] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.05 mol / L.

[0180] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0181] (2) Preparation of composite metal oxide desulfurizer

[0182] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0183] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S13.

[0184] Comparative Example 6

[0185] This comparative example provides a method for preparing a composite metal oxide desulfurizer, the specific steps of which include:

[0186] (1) Preparation of hydrotalcite compounds

[0187] Prepare 500 mL of a mixed solution of magnesium nitrate, aluminum nitrate, cerium nitrate, and urea, recorded as mixed solution A. The concentration of magnesium nitrate is 0.65 mol / L, the concentration of aluminum nitrate is 0.31 mol / L, the concentration of cerium nitrate is 0.04 mol / L, and the concentration of urea is 10 mol / L.

[0188] 250 mL of an aqueous solution of a gemini anionic surfactant J was prepared and recorded as mixed solution B, wherein the concentration of the gemini anionic surfactant J was 0.8 mol / L.

[0189] After stirring the mixture A and B at room temperature for 0.5 h, the mixture was transferred to a 1000 mL polytetrafluoroethylene autoclave and reacted at 160°C under a nitrogen atmosphere for 12 h. The mixture was then centrifuged and washed with deionized water until neutral, followed by a final wash with ethanol. The resulting solid was dried in a 90°C oven overnight and then ground into a powder (300-500 mesh), i.e., a hydrotalcite-like compound powder.

[0190] (2) Preparation of composite metal oxide desulfurizer

[0191] The hydrotalcite compound powder obtained in step (1) was transferred to a muffle furnace and calcined at 500° C. for 6 h in an air atmosphere to obtain the corresponding composite metal oxide powder, wherein the heating rate was 2° C. / min.

[0192] Weigh 50g of composite metal oxide powder, add 40g of aluminum sol, 2.7g of sesbania powder and 50g of deionized water, mix thoroughly and extrude into shape, then place at room temperature for 48h, dry at 100℃ for 12h, and calcine at 500℃ for 4h to obtain the corresponding desulfurizer S14.

[0193] (I) Activity evaluation: The composition of the inlet raw gas of this test is shown in Table 1. The desulfurization reaction space velocity is 500h -1 The desulfurization activity was evaluated at a reaction temperature of 500°C.

[0194] Table 1

[0195] The evaluation test began by weighing 3g of the preformed desulfurizer (used in the Examples and Comparative Examples) and loading it into a fixed-bed microreactor. The upper and lower layers were secured with quartz wool. During the reaction, when the SO2 content in the outlet gas exceeded 140ppm, the reaction was switched to a reducing gas flow. After regeneration, the next desulfurization reaction cycle was entered. The sulfur capacity of the desulfurizer at this point was calculated, and the results are shown in Table 2.

[0196] Table 2 Note: cat. is a desulfurizing agent.

[0197] (2) Specific surface area and pore size test: A fully automatic specific surface area and porosity analyzer was used to conduct N2 adsorption and desorption tests to measure the specific surface areas and pore sizes of the desulfurizers of Examples 1 to 12 and Comparative Examples 1 to 6. The results are shown in Table 3.

[0198] Table 3

[0199] The sulfur capacity of the above-mentioned desulfurizers of the present invention (such as Examples 1-12) can reach 0.20gSO2 / gcat. or above, while the sulfur capacity of the desulfurizers in Comparative Examples 1-6 is less than 0.20gSO2 / gcat. Further:

[0200] When the hydrophobic chains are the same but the linkers are different, the hydrophobicity of the active agent does not increase with the increase of the carbon number of the linker, but the hydrophilicity of the linker and the hydrophilicity of the hydrophilic group are balanced. The addition of only one carbon atom to the molecular linker significantly increases the hydrophobicity, resulting in an overall increase in the hydrophilicity of the molecule. This slightly reduces the stability of the emulsion formed during the hydrothermal reaction, thus slightly outperforming Example 2. As the linker length increases further, the hydrophobicity of the linker becomes stronger than the hydrophilicity of the hydrophilic group, resulting in increased hydrophobicity and decreased solubility in water. Therefore, Example 3 is slightly superior to Example 12.

[0201] When the linking groups are the same and the hydrophobic chain lengths are different, as the carbon chain length increases, the hydrophilicity of the active agent decreases, the lipophilicity increases, and the interfacial tension gradually decreases, thereby resulting in a more stable emulsion formed during the hydrothermal reaction, a more uniform morphology of the hydrotalcite crystals, and a higher reactivity of the desulfurizer. Therefore, Example 3 is slightly better than Example 1.

[0202] Too low a surfactant dosage will make it difficult to disperse and form droplets, and the emulsion will be unstable; while too high a dosage may lead to over-emulsification, the droplets become too small, and the stability of the emulsion is affected. Therefore, Example 3 is slightly better than Examples 4 and 5.

[0203] The concentration of the precipitant will affect the crystallinity of the hydrotalcite compound. If the amount of the precipitant is too high or too low, it will affect the OH - concentration, and then the hydrothermal reaction generates other impurities, which affects the dispersion of the active metals. Therefore, Example 3 is slightly better than Examples 10 and 11.

[0204] The hydrothermal reaction temperature affects the crystallinity of the crystal. As the temperature increases, the crystallinity gradually increases and then gradually remains unchanged. Therefore, Examples 3 and 9 are slightly better than Example 8.

[0205] The calcination temperature will affect the structure of the final crystal, and thus affect the activity of the desulfurizer. Among them, hydrotalcite compounds decompose when heated to a certain temperature. The thermal decomposition process includes steps such as dehydration of interlayer water, decarbonation of carbonate ions, and dehydration of hydroxyl groups in the layer. When it is lower than 200℃, only interlayer water is lost, which has no effect on its structure. When heated to 250-450℃, more water is lost and CO2 is generated. When heated to 450-500℃, CO3 2- The LDHs disappear and are completely converted into CO2, forming a bimetallic composite oxide. During the heating process, the ordered layered structure of the LDHs is destroyed, the surface area increases, and the pore volume increases. When the heating temperature exceeds 600°C, the metal oxides formed after decomposition begin to sinter, resulting in a decrease in surface area and pore volume, forming a spinel phase. Therefore, Example 3 is slightly superior to Examples 6 and 7.

Claims

1. A desulfurizer, wherein, The desulfurizer is a composite metal oxide, and the metal elements in the composite metal oxide include magnesium and aluminum; the specific surface area of the desulfurizer is ≥ 180 m 2 / g.

2. The desulfurizer according to claim 1, wherein The specific surface area of the desulfurizer is 184 to 219 m 2 / g, and the pore diameter is 16 to 21 nm.

3. The desulfurizer according to claim 1 or 2, wherein The metal element in the composite metal oxide further includes cerium.

4. The desulfurizer according to claim 3, wherein, The structural formula of the desulfurizer is A a B b C c O x , where A is magnesium, B is aluminum, C is cerium, a:b:c is 2:1.7 - 7.29:0.1 - 0.5, and the value of x satisfies the positive and negative valence balance of the desulfurizer.

5. A preparation method of a desulfurizer, wherein, Including: Mixing the mixed solution A containing magnesium salt, aluminum salt, and precipitant with the mixed solution B with a molar concentration of 0.1 - 0.5 mol / L of gemini anionic surfactant, followed by hydrothermal reaction, and successively washing, drying, grinding, first calcining, shaping, and second calcining the precipitate obtained from the hydrothermal reaction to obtain the desulfurizer; The gemini anionic surfactant has the structure shown in Formula I: In the formula I, 10 ≤ n ≤ 16, 2 ≤ m ≤ 6, and both n and m are integers.

6. The preparation method of the desulfurizer according to claim 5, wherein, The raw materials for forming the mixed solution A further include cerium salt.

7. The preparation method of the desulfurizer according to claim 5 or 6, wherein, The precipitant is selected from one or more of urea, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

8. The preparation method of the desulfurizer according to claim 5 or 6, wherein, In the mixed solution A, the molar concentration of the precipitant is 8 - 12 mol / L.

9. The preparation method of the desulfurizer according to claim 5, wherein, In the mixed solution A, the total molar concentration of magnesium element, aluminum element, and cerium element is 0.8 - 1.2 mol / L.

10. The preparation method of the desulfurizer according to claim 5, wherein, In the mixed solution A, the molar ratio of magnesium element, aluminum element, and cerium element is 2:0.5 - 1:0.1 - 0.

5.

11. The preparation method of the desulfurizer according to claim 5, wherein, After the first calcining and before the shaping, the preparation method further includes the step of mixing the first calcined product with a binder and a pore-forming agent to form a mixed system C.

12. The preparation method of the desulfurizer according to claim 11, wherein, The binder is selected from one or more of aluminum sol, high-temperature resistant cement, or pseudo-boehmite.

13. The preparation method of the desulfurizer according to claim 11, wherein, The pore-forming agent is selected from one or more of sesbania powder, carboxymethyl cellulose, starch, and cetyltrimethylammonium bromide.

14. The preparation method of the desulfurizer according to claim 11, wherein, In the mixed system C, the weight content of the pore-forming agent is 1 - 5 wt%.

15. The preparation method of the desulfurizer according to claim 11, wherein, The weight ratio of the binder to the first calcined product is 1:1 - 3.

16. The preparation method of the desulfurizer according to claim 5, wherein, The temperature of the hydrothermal reaction is 140 - 180 °C and the time is 8 - 16 h.

17. The preparation method of the desulfurizer according to claim 5, wherein, The temperature of the first calcining and the second calcining are each independently 450 - 600 °C, and the time is each independently 5 - 12 h.

18. Application of the desulfurizer according to any one of claims 1 to 4 in flue gas desulfurization.

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