Anti-heavy metal poisoning denitration catalyst and preparation method thereof

Abstract

The invention relates to the technical field of selective catalytic reduction catalysts, in particular to an anti-heavy metal poisoning denitration catalyst and a preparation method thereof.The preparation method comprises the steps that a natural mineral material is soaked in an aqueous solution of magnesium salt or zinc salt, drying and calcining are conducted in sequence, and the natural mineral material loaded with magnesium or zinc is obtained; adding an inorganic binder and an organic binder into the aqueous solution of the natural mineral material loaded with magnesium or zinc, and carrying out ball milling to obtain slurry; and soaking the formed denitration catalyst in the slurry, and sequentially purging, drying and calcining to obtain the denitration catalyst capable of resisting heavy metal poisoning. The Mg / Zn modified natural mineral material is adopted as a heavy metal removal material, on one hand, the characteristics of porosity, large specific surface area and the like of the natural mineral material are utilized to adsorb heavy metal ions in flue gas, and on the other hand, MgO or ZnO is loaded on the surface of the natural mineral material to increase ion exchange sites of the material surface to the heavy metal ions, so that the heavy metal removal effect is improved. The capturing capability of the material on heavy metal ions is further enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of selective catalytic reduction catalysts, and in particular to a heavy metal poisoning resistant denitration catalyst and a preparation method thereof. Background Art

[0002] Nitrogen oxides (NO x ), as an important type of air pollutant, its direct emission poses a serious threat to the environment and human health. Specifically, the emission of nitrogen oxides not only causes photochemical smog and ozone layer destruction, but is also one of the key factors in the formation of acid rain, and has a profound impact on the human respiratory system, cardiovascular system, etc. Therefore, effectively controlling the emission of nitrogen oxides has become an important issue in global environmental protection.

[0003] To meet this challenge, Selective Catalytic Reduction (SCR) technology came into being and gradually became the mainstream technology for removing nitrogen oxides. The core of this technology is to use efficient denitration catalysts to convert nitrogen oxides into harmless nitrogen and water under mild conditions, thereby achieving effective purification of pollutants. However, in practical applications, the activity of denitration catalysts is often affected by a variety of factors and gradually decreases, among which heavy metal poisoning is a problem worthy of attention.

[0004] There is a complex interaction between heavy metal pollutants and denitrification catalysts. These heavy metal elements will deposit on the catalyst surface, not only occupying the active sites originally used for catalytic reactions, but also destroying the acid sites and redox properties of the catalyst, which in turn leads to a significant reduction in catalyst activity and shortened service life. Therefore, how to effectively prevent heavy metal poisoning and improve the stability and durability of denitrification catalysts has become a key technical problem that needs to be solved in this field.

[0005] Although some studies have attempted to improve the ability of catalysts to resist heavy metal poisoning by improving their preparation methods, such as the heavy metal poisoning-resistant SCR denitration catalyst disclosed in invention patent CN202111115449.9, which effectively avoids the deposition of heavy metals on the active components and improves the denitration performance by introducing nano manganese dioxide into the vanadium-titanium denitration catalyst. However, in practical applications, this technology still faces limitations such as poor resistance to sulfur water and weak resistance to poisoning of some heavy metal elements, making it difficult to meet increasingly stringent environmental protection requirements and complex industrial application environments.

[0006] In view of this, the development of a new denitration catalyst with excellent resistance to heavy metal poisoning, high stability and durability is not only of great significance for promoting the further development of SCR technology, but also an urgent need to achieve efficient reduction of nitrogen oxides, protect the ecological environment and human health. Therefore, the present invention aims to provide an innovative denitration catalyst and a preparation method thereof to overcome the shortcomings of the prior art and meet the urgent needs in practical applications. Summary of the invention

[0007] The purpose of the present invention is to provide a heavy metal poisoning resistant denitration catalyst and a preparation method thereof. The heavy metal poisoning resistant denitration catalyst prepared by the present invention not only has excellent heavy metal poisoning resistance, but also has the advantages of strong wear resistance and high denitration efficiency.

[0008] In a first aspect, the present invention provides a method for preparing a heavy metal poisoning resistant denitration catalyst, comprising the following steps:

[0009] S1, immersing the natural mineral material in an aqueous solution of a magnesium salt or a zinc salt, and sequentially drying and calcining to obtain a natural mineral material loaded with magnesium or zinc;

[0010] S2, adding an inorganic binder and an organic binder to an aqueous solution of a natural mineral material loaded with magnesium or zinc, and ball milling to obtain a slurry;

[0011] S3. Immerse the formed denitration catalyst in the slurry, and sequentially purge, dry and calcine the slurry to obtain a denitration catalyst resistant to heavy metal poisoning.

[0012] As a preferred embodiment of the present technical solution, in step S1, the natural mineral material includes any one or more of attapulgite, sepiolite, kaolin, diatomaceous earth, hydroxyapatite and wollastonite;

[0013] The magnesium salt or zinc salt includes any one or more of chloride, nitrate and sulfate.

[0014] The present invention uses magnesium salt or zinc salt to modify natural mineral materials. On the one hand, the characteristics of the porous surface and large specific surface area of ​​attapulgite, sepiolite, kaolin, diatomaceous earth, hydroxyapatite and wollastonite natural mineral materials are utilized, and the characteristic that MgO or ZnO is loaded on the surface of the natural mineral materials to increase the ion exchange sites of the material surface for heavy metal ions; on the other hand, the present invention uses magnesium salt or zinc salt to modify the attapulgite, sepiolite, kaolin, diatomaceous earth, hydroxyapatite and wollastonite natural mineral materials. Since magnesium ions or zinc ions can enter the interlayer or lattice of the mineral to form structural reconstruction during the modification process, and can also form a coating layer through electrostatic adsorption or chemical bonds, the surface properties and mechanical properties of the mineral material can be improved and the adsorption performance can be enhanced.

[0015] As a preferred embodiment of the present technical solution, in step S1, during the impregnation, the solid-liquid ratio is controlled to be 1:(4-10), the temperature of the solution is 80-90°C, and the impregnation time is 2-4h;

[0016] During the impregnation process, magnesium or zinc ions will combine with the active sites on the surface of natural mineral materials to form one or more loading layers. This loading layer can not only increase the specific surface area of ​​the catalyst, but also provide more active sites, which is beneficial to the subsequent catalytic reaction. In addition to surface loading, some magnesium or zinc ions can also penetrate into the interior through the pore structure of natural mineral materials to form a more uniform loading distribution. This internal penetration helps to enhance the overall stability and durability of the catalyst. Finally, in some cases, sodium, potassium, and calcium ions in natural mineral materials may exchange with magnesium or zinc ions, thereby further changing their surface chemical properties and catalytic performance.

[0017] Preferably, during the impregnation, the solid-liquid ratio is controlled to be 1:(4-10), after stirring at room temperature for 1-4 hours, the pH value of the solution is adjusted to 10-12, and stirring is continued at 80-90°C for 2-4 hours.

[0018] During the impregnation process, the solution is adjusted to a pH value of 10-12, which is conducive to the adsorption and penetration of magnesium or zinc ions on the surface of the natural mineral material. Within this pH range, magnesium or zinc ions are more likely to react with active sites on the surface of the natural mineral material to form a more stable load layer.

[0019] As a preferred embodiment of the present technical solution, in step S1, in the natural mineral material loaded with magnesium or zinc, MgO or ZnO accounts for 0.5%-5% of the mass of the natural mineral material.

[0020] As a preferred embodiment of the present technical solution, in step S1, after the impregnation is completed, it is first allowed to stand for aging for 6-12 hours, then filtered, washed and dried in sequence, and finally calcined at 400-600°C for 3-6 hours.

[0021] The present invention introduces a static aging process after impregnation, which not only helps the further diffusion and uniform distribution of magnesium or zinc ions in the natural mineral material, but also the aging process can trigger some slow chemical reactions, such as the formation of chemical bonds and the rearrangement of the structure, which are all conducive to improving the stability and catalytic performance of the catalyst.

[0022] As a preferred embodiment of the present technical solution, in step S2, the inorganic binder includes any one or both of aluminum sol and silica sol;

[0023] Among them, the main component of aluminum sol is aluminum oxide (Al2O3), which is a component present in many natural mineral materials. Therefore, it has good compatibility with natural mineral materials loaded with magnesium or zinc; in addition, aluminum sol is not easy to decompose at high temperatures and can provide stable high-temperature mechanical strength for the catalyst; finally, aluminum oxide itself has a certain catalytic activity, which helps to improve the overall performance of the catalyst.

[0024] Silica sol can significantly improve the mechanical strength of the catalyst, especially at high temperatures. The addition of silica sol can prevent the catalyst from being damaged or peeled off during use. In addition, silica sol has excellent dispersibility and can be evenly distributed in the catalyst to ensure close bonding between the components. Finally, silica sol has good corrosion resistance and helps to increase the service life of the catalyst in harsh environments.

[0025] The organic binder includes any one or more of methyl cellulose, hydroxypropyl cellulose and hydroxymethylpropyl cellulose.

[0026] Among them, methyl cellulose can well bind the various components in the catalyst together to form a whole, thereby improving the stability and mechanical strength of the catalyst; in addition, methyl cellulose is easily soluble in water, which makes it easy to mix evenly with inorganic binders and natural mineral materials loaded with magnesium or zinc during the preparation process.

[0027] Hydroxypropyl cellulose can maintain moisture in the slurry and prevent the water from evaporating too quickly during the preparation process, which may lead to a decrease in catalyst performance. In addition, hydroxypropyl cellulose can improve the dispersibility of the components in the catalyst and ensure that the components are evenly distributed.

[0028] Hydroxymethylpropyl cellulose combines the advantages of methyl cellulose and hydroxypropyl cellulose, and has excellent adhesion, dispersibility and water retention. It can adjust the viscosity of the slurry as needed, which is convenient for subsequent molding and processing.

[0029] As a preferred embodiment of the present technical solution, in step S2, the mass ratio of the natural mineral material loaded with magnesium or zinc, the inorganic binder and the organic binder is (5-10): (0.1-1): (2-10), wherein the mass of the inorganic binder is calculated by converting it into the mass of Al2O3 or SiO2.

[0030] As a preferred embodiment of the present technical solution, in step S3, the shaped denitration catalyst includes any one of a flat plate type, a honeycomb type, and a corrugated plate type. The form of the shaped denitration catalyst is not strictly limited in the present invention.

[0031] As a preferred embodiment of the present technical solution, in step S3, the soaking time is controlled to be 0.5-5min;

[0032] During the purging, compressed air is used to purge and remove excess slurry on the catalyst surface and in the pores;

[0033] During the calcination, the temperature is controlled at 400-600° C. and the time is 2-4 hours.

[0034] The present invention can repeat the steps of soaking, purging and drying for multiple times according to the loading amount of the natural mineral material until the target loading amount of the natural mineral material is reached.

[0035] In the second aspect, the present invention also discloses a heavy metal poisoning resistant denitration catalyst prepared by the above preparation method. Specifically, natural mineral materials account for 1%-5% of the mass of the heavy metal poisoning resistant denitration catalyst; MgO or ZnO accounts for 0.5%-5% of the mass of the natural mineral materials.

[0036] The preparation method of the heavy metal poisoning resistant denitration catalyst of the present invention has at least the following beneficial effects:

[0037] 1. In the preparation method of the heavy metal poisoning resistant denitrification catalyst of the present invention, Mg / Zn modified natural mineral materials are used as heavy metal removal materials. On the one hand, the porous and large specific surface area characteristics of natural mineral materials are utilized to adsorb heavy metal ions in flue gas. On the other hand, MgO or ZnO is loaded on the surface of the natural mineral materials to increase the ion exchange sites on the surface of the material for heavy metal ions, thereby further enhancing the material's ability to capture heavy metal ions.

[0038] 2. The preparation method of the heavy metal poisoning resistant denitration catalyst of the present invention is to improve the shaped denitration catalyst. It only needs to load the Mg / Zn modified natural mineral material on the surface of the shaped denitration catalyst in the form of a coating, which can not only significantly enhance the heavy metal poisoning resistance of the catalyst, but also effectively improve the mechanical strength of the catalyst and increase the wear resistance of the catalyst.

[0039] 3. The preparation process of the present invention is simple and is applicable to various types of industrial denitrification catalysts. The raw materials used in the preparation of the material are cheap and easily available, and have high industrial applicability. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] S1. Prepare magnesium chloride solution, immerse attapulgite in magnesium chloride aqueous solution according to the solid-liquid ratio of 1:4, stir at room temperature for 4 hours, slowly add NaOH solution until the solution pH value is 10-12, continue to stir in a water bath at 80°C for 4 hours, let stand for 12 hours, then filter, wash, dry, and calcine at 400°C for 6 hours to obtain magnesium-loaded attapulgite;

[0045] S2. Weigh magnesium-loaded attapulgite and add it to deionized water, wherein the mass fraction of magnesium-loaded attapulgite is 5wt%, further add aluminum sol and methyl cellulose, and ball mill for 6h to obtain a slurry, wherein the aluminum sol accounts for 2% of the natural mineral material in terms of Al2O3, and the amount of methyl cellulose added is 3% of the mass of deionized water;

[0046] S3. Soak the flat-plate denitration catalyst in the slurry for 2 minutes, take it out, blow off the excess slurry on the catalyst surface and in the pores with compressed air, dry the catalyst, and calcine it at 400° C. for 4 hours to obtain a denitration catalyst resistant to heavy metal poisoning.

[0047] In the heavy metal poisoning resistant denitration catalyst obtained in this embodiment, MgO accounts for 0.5% of the mass of attapulgite, and attapulgite accounts for 1% of the weight of the denitration catalyst.

[0048] The flat plate denitration catalyst used has a V2O5 content of 1.5wt% and a MoO3 content of 3wt%.

[0049] Example 2

[0050] S1. Prepare zinc nitrate solution, immerse sepiolite in the zinc nitrate aqueous solution at a solid-liquid ratio of 1:10, stir at room temperature for 4 hours, slowly add NaOH solution until the solution pH value is 10-12, continue to stir in a 90°C water bath for 2 hours, let stand for 12 hours, then filter, wash, dry, and calcine at 600°C for 3 hours to obtain zinc-loaded sepiolite;

[0051] S2, weighing zinc-loaded sepiolite, adding it to deionized water, the mass fraction of zinc-loaded sepiolite is 10wt%, further adding silica sol and hydroxypropyl cellulose, and ball milling for 24h to prepare a slurry, wherein the silica sol accounts for 10% of the mass of the sepiolite in terms of SiO2, and the amount of hydroxypropyl cellulose added is 8% of the mass of deionized water;

[0052] S3. Soak the flat-plate denitration catalyst in the slurry for 0.5 min, take it out, blow it with compressed air to remove excess slurry on the catalyst surface and in the pores, dry the catalyst, and calcine it at 600° C. for 2 h to obtain a denitration catalyst resistant to heavy metal poisoning.

[0053] In the heavy metal poisoning resistant denitration catalyst obtained in this embodiment, ZnO accounts for 5% of the mass of sepiolite, and sepiolite accounts for 5% of the mass of the denitration catalyst.

[0054] The flat plate denitration catalyst used has a V2O5 content of 1.2wt% and a MoO3 content of 3wt%.

[0055] Example 3

[0056] S1. Prepare magnesium sulfate solution, soak kaolin in magnesium sulfate aqueous solution according to the solid-liquid ratio of 1:6, stir at room temperature for 4 hours, slowly add NaOH solution until the solution pH value is 10-12, continue to stir in 85°C water bath for 3 hours, let stand for 12 hours, then filter, wash, dry, and calcine at 500°C for 5 hours to obtain magnesium-loaded kaolin;

[0057] S2, weighing magnesium-loaded kaolin, adding it to deionized water, wherein the mass fraction of magnesium-loaded kaolin is 8wt%, further adding aluminum sol and hydroxymethyl propyl cellulose, and ball milling for 12h to prepare a slurry, wherein the aluminum sol accounts for 5% of the kaolin in terms of Al2O3, and the amount of hydroxymethyl propyl cellulose added is 4% of the mass of deionized water;

[0058] S3. Soak the honeycomb denitration catalyst in the slurry for 5 minutes, take it out, and use compressed air to blow away the excess slurry on the catalyst surface and in the pores. Dry the catalyst and calcine it at 500° C. for 3 hours to obtain a denitration catalyst resistant to heavy metal poisoning.

[0059] In the heavy metal poisoning resistant denitration catalyst obtained in this example, MgO accounts for 2% of the mass of kaolin, and kaolin accounts for 2% of the weight of the denitration catalyst.

[0060] The honeycomb denitration catalyst used has a V2O5 content of 1wt% and a WO3 content of 2.8wt%.

[0061] Example 4

[0062] S1. Prepare magnesium chloride aqueous solution, add diatomaceous earth at a solid-liquid ratio of 1:4, stir at room temperature for 4 hours, slowly add NaOH solution until the pH value of the solution reaches 10-12, continue stirring in a water bath at 85°C for 4 hours, let stand for aging for 12 hours, then filter, wash, dry, and calcine at 400°C for 6 hours to obtain magnesium-loaded diatomaceous earth;

[0063] S2, weigh magnesium-loaded diatomaceous earth, add it to deionized water, the mass fraction of magnesium-loaded diatomaceous earth is 5wt%, add silica sol and methyl cellulose, and ball mill for 6h to prepare a slurry, wherein the silica sol accounts for 8% of the mass of the diatomaceous earth in terms of SiO2, and the amount of methyl cellulose added is 6% of the mass of deionized water;

[0064] S3. Soak the corrugated plate denitration catalyst in the slurry for 1 minute, take it out, and use compressed air to blow away excess slurry on the catalyst surface and in the pores. Dry the catalyst and calcine it at 450° C. for 4 hours to obtain a denitration catalyst resistant to heavy metal poisoning.

[0065] In the heavy metal poisoning resistant denitration catalyst obtained in this embodiment, MgO accounts for 1% of the mass of diatomaceous earth, and magnesium chloride accounts for 3% of the weight of the denitration catalyst.

[0066] The corrugated plate denitration catalyst used has a V2O5 content of 0.8wt% and a WO3 content of 2.5wt%.

[0067] Example 5

[0068] S1. Prepare a zinc nitrate aqueous solution, add hydroxyapatite at a solid-liquid ratio of 1:10, stir at room temperature for 2 hours, slowly add a NaOH solution until the pH value of the solution reaches 10-12, continue stirring in a water bath at 85°C for 4 hours, let stand for aging for 12 hours, then filter, wash, dry, and calcine at 600°C for 3 hours to obtain zinc-loaded hydroxyapatite;

[0069] S2. Weigh zinc-loaded hydroxyapatite, add it to deionized water, the mass fraction of the material is 5-10wt%, add aluminum sol and hydroxypropyl cellulose, and ball mill for 6h to prepare a slurry, wherein the aluminum sol accounts for 5% of the mass of hydroxyapatite in terms of Al2O3, and the amount of hydroxypropyl cellulose added is 6% of the mass of deionized water;

[0070] S3. Soak the honeycomb denitration catalyst in the slurry for 2 minutes, take it out, and use compressed air to blow away the excess slurry on the catalyst surface and in the pores. Dry the catalyst and calcine it at 600° C. for 3 hours to obtain a denitration catalyst resistant to heavy metal poisoning.

[0071] In the heavy metal poisoning resistant denitration catalyst obtained in this embodiment, ZnO accounts for 3% of the mass of hydroxyapatite, and hydroxyapatite accounts for 4% of the weight of the denitration catalyst.

[0072] The honeycomb denitration catalyst used has a V2O5 content of 1.6wt% and a WO3 content of 2.5wt%.

[0073] Comparative Example 1

[0074] This comparative example uses a molded denitrification catalyst as a control.

[0075] In the flat plate denitration catalyst of this comparative example, the V2O5 content is 1.5wt% and the MoO3 content is 3wt%.

[0076] Comparative Example 2

[0077] This control example is basically the same as Example 1, except that magnesium chloride is not used to modify the attapulgite.

[0078] The specific steps are as follows:

[0079] S1. Weigh attapulgite, add it to deionized water, the mass fraction of attapulgite is 5wt%, add aluminum sol and methyl cellulose, and ball mill for 6h to prepare a slurry, wherein the aluminum sol accounts for 2% of the natural mineral material in terms of Al2O3, and the amount of methyl cellulose added is 3% of the mass of deionized water;

[0080] S2. Soak the flat-plate denitration catalyst in the slurry for 2 minutes, take it out, and use compressed air to blow away excess slurry on the catalyst surface and in the pores. Dry the catalyst and calcine it at 400°C for 4 hours to obtain a denitration catalyst resistant to heavy metal poisoning.

[0081] In the heavy metal poisoning resistant denitration catalyst obtained in this comparative example, MgO accounts for 0.5% of the mass of attapulgite, and attapulgite accounts for 1% of the weight of the denitration catalyst.

[0082] The flat plate denitration catalyst used has a V2O5 content of 1.5wt% and a MoO3 content of 3wt%.

[0083] Comparative Example 3

[0084] This control example is basically the same as Example 1, except that attapulgite is modified using ferric chloride solution.

[0085] In the heavy metal poisoning resistant denitration catalyst obtained in this comparative example, Fe3O4 accounts for 0.5% of the mass of attapulgite, and attapulgite accounts for 1% of the weight of the denitration catalyst.

[0086] The flat plate denitration catalyst used has a V2O5 content of 1.5wt% and a MoO3 content of 3wt%.

[0087] Comparative Example 4

[0088] This comparative example is substantially the same as Example 1, except that the vermiculite is modified using a magnesium chloride solution.

[0089] In the heavy metal poisoning resistant denitration catalyst obtained in this comparative example, MgO accounts for 0.5% of the mass of vermiculite, and vermiculite accounts for 1% of the weight of the denitration catalyst.

[0090] The flat plate denitration catalyst used has a V2O5 content of 1.5wt% and a MoO3 content of 3wt%.

[0091] Comparative Example 5

[0092] This comparative example is basically the same as Example 2, except that the sepiolite is modified using an aluminum sulfate solution.

[0093] In the heavy metal poisoning resistant denitration catalyst obtained in this comparative example, Al2O3 accounts for 5% of the mass of sepiolite, and sepiolite accounts for 5% of the weight of the denitration catalyst.

[0094] The flat plate denitration catalyst used has a V2O5 content of 1.2wt% and a MoO3 content of 3wt%.

[0095] Comparative Example 6

[0096] This comparative example is basically the same as Example 2, except that the montmorillonite is modified using zinc nitrate solution.

[0097] In the heavy metal poisoning resistant denitration catalyst obtained in this comparative example, ZnO accounts for 5% of the mass of montmorillonite, and montmorillonite accounts for 5% of the weight of the denitration catalyst.

[0098] The flat plate denitration catalyst used has a V2O5 content of 1.2wt% and a MoO3 content of 3wt%.

[0099] Test Example 1

[0100] The present invention conducts abrasion resistance tests on the denitration catalysts in the above embodiments and control examples, and the data are shown in Table 1.

[0101] Table 1 Wear resistance of different denitrification catalysts

[0102]

[0103]

[0104] As can be seen from Table 1, the present invention loads the Mg / Zn-modified natural mineral material on the surface of the molded denitration catalyst in the form of a coating, and improves the molded denitration catalyst, which can effectively improve the mechanical strength of the catalyst and enhance the wear resistance of the catalyst.

[0105] Test Example 2

[0106] The present invention tests the denitration performance of the denitration catalysts prepared in the above examples and control examples.

[0107] The test conditions are as follows: test temperature is 350℃, NH3 concentration is 500ppm, NH3 / NO=1, SO2 concentration is 500ppm, H2O concentration is 8%, GHSV=120000h -1 .

[0108] The denitrification efficiencies of different denitrification catalysts are shown in Table 2.

[0109] Table 2 Denitrification efficiency of different denitrification catalysts

[0110]

[0111]

[0112] As can be seen from Table 2, the present invention loads the Mg / Zn modified natural mineral material on the surface of the formed denitration catalyst in the form of a coating, and improves the formed denitration catalyst, which not only does not affect the denitration efficiency of the denitration catalyst, but will improve the denitration efficiency of the denitration catalyst to a certain extent. This may be because the Mg / Zn modified natural mineral material as a partial carrier can optimize the pore structure to a certain extent, and has a dispersing effect on the distribution of active species and additives.

[0113] Test Example 3

[0114] In order to further verify the anti-heavy metal poisoning characteristics of the denitration catalysts prepared in the above embodiments and control examples, the present invention subjected the denitration catalysts in the above embodiments and control examples to simulate lead poisoning.

[0115] Specifically, a certain amount of sieved catalyst powder was weighed and placed in a precursor solution prepared by lead acetate, and the mixture was stirred continuously in a water bath at 80°C to make it uniformly mixed, and after being impregnated until dry, it was placed in a forced air drying oven at 110°C for 12 hours, and then calcined at 550°C for 2 hours to obtain a denitration catalyst simulating lead poisoning. The lead loading content on the simulated poisoned catalyst was controlled to be 1wt%.

[0116] Furthermore, the denitration performance of the catalyst after simulated lead poisoning was tested under the same conditions as in Test Example 2. The test results are shown in Table 3.

[0117] Table 3 Denitrification efficiency of different denitrification catalysts

[0118]

[0119] As can be seen from Table 3, loading the Mg / Zn-modified natural mineral material on the surface of the molded denitration catalyst in the form of a coating and improving the molded denitration catalyst can significantly enhance the denitration catalyst's ability to capture heavy metal ions and improve the denitration catalyst's resistance to heavy metals.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a heavy metal poisoning resistant denitration catalyst, characterized in that: The following steps are involved: S1, immersing the natural mineral material in an aqueous solution of a magnesium salt or a zinc salt, and drying and calcining the natural mineral material in sequence to obtain a magnesium or zinc loaded natural mineral material; S2, adding an inorganic binder and an organic binder to an aqueous solution of a natural mineral material loaded with magnesium or zinc, and ball milling to obtain a slurry; S3. Immerse the formed denitration catalyst in the slurry, and sequentially purge, dry and calcine the slurry to obtain a denitration catalyst resistant to heavy metal poisoning.

2. The preparation method according to claim 1, characterized in that: In step S1, the natural mineral material includes any one or more of attapulgite, sepiolite, kaolin, diatomaceous earth, hydroxyapatite and wollastonite; The magnesium salt or zinc salt includes any one or more of chloride, nitrate and sulfate.

3. The preparation method according to claim 1, characterized in that: In step S1, during the immersion, the solid-liquid ratio is controlled to be 1:(4-10), the solution temperature is 80-90° C., and the immersion time is 2-4 hours; Preferably, during the impregnation, the solid-liquid ratio is controlled to be 1:(4-10), after stirring at room temperature for 1-4 hours, the pH value of the solution is adjusted to 10-12, and after continuing to stir at 80-90°C for 2-4 hours, it is allowed to stand for aging for 6-12 hours.

4. The preparation method according to claim 1, characterized in that: In step S1, in the natural mineral material loaded with magnesium or zinc, MgO or ZnO accounts for 0.5%-5% of the mass of the natural mineral material.

5. The preparation method according to claim 1, characterized in that: In step S1, after the impregnation is completed, the mixture is first aged for 6-12 hours, then filtered, washed and dried in sequence, and finally calcined at 400-600°C for 3-6 hours.

6. The preparation method according to claim 1, characterized in that: In step S2, the inorganic binder includes any one or both of aluminum sol and silica sol; The organic binder includes any one or more of methyl cellulose, hydroxypropyl cellulose and hydroxymethylpropyl cellulose.

7. The preparation method according to claim 1, characterized in that: In step S2, the mass ratio of the natural mineral material loaded with magnesium or zinc, the inorganic binder and the organic binder is (5-10): (0.1-1): (2-10), wherein the mass of the inorganic binder is calculated in terms of the mass converted into Al2O3 or SiO2.

8. The preparation method according to claim 1, characterized in that: In step S3, the shaped denitration catalyst includes any one of a flat plate type, a honeycomb type, and a corrugated plate type.

9. The preparation method according to claim 1, characterized in that: In step S3, the soaking time is controlled to be 0.5-5min; During the purging, compressed air is used to purge and remove excess slurry on the catalyst surface and in the pores; During the calcination, the temperature is controlled at 400-600° C. and the time is 2-4 hours.

10. A heavy metal poisoning resistant denitrification catalyst, characterized in that: The catalyst is prepared according to the preparation method according to any one of claims 1 to 9, wherein the natural mineral material accounts for 1% to 5% of the mass of the heavy metal poisoning resistant denitration catalyst; and MgO or ZnO accounts for 0.5% to 5% of the mass of the natural mineral material.

Images