A method for preparing a denitration catalyst using stepped fibers and the denitration catalyst

Abstract

The present invention relates to the field of denitration technology, and discloses a method for preparing a denitration catalyst using stepped fibers and a denitration catalyst. The method includes: mixing titanium dioxide, pretreated glass fiber A and organic solvent C to obtain modified titanium dioxide; mixing a tungsten source, the modified titanium dioxide, a vanadium source, an alcohol compound of C1-C10 and an ammonia aqueous solution to obtain a titanium-tungsten-vanadium mixture; kneading pretreated glass fiber B, the titanium-tungsten-vanadium mixture, a lubricant, pretreated glass fiber C, pretreated glass fiber D, a binder, a plasticizer and pretreated glass fiber E, and then aging, extrusion molding and sintering. The method of the present invention can achieve the gradient utilization of glass fibers, and apply glass fibers of different lengths to the preparation of the denitration catalyst at the same time, which can lay a foundation for the subsequent recovery of glass fibers of different lengths.

Description

Technical Field

[0001] The present invention relates to the technical field of denitration, and particularly relates to a method for preparing a denitration catalyst by using stepped fibers and a denitration catalyst. Background Art

[0002] Coal is the main energy source in China. Nitrogen oxides in coal-fired flue gas are pollutants that need to be key controlled, and among them, NH3-SCR is the most popular flue gas denitration method at present.

[0003] The denitration catalyst is the key in the SCR reaction. The commonly used denitration catalyst in industry is a honeycomb vanadium-titanium-based denitration catalyst, which has high efficiency. The main components in the catalyst are metal oxides, and there are also a small amount of glass fibers. In the traditional preparation method of the denitration catalyst, short-cut fibers of a specific length are usually used, and the length is relatively uniform. At the same time, the prior art lacks exploration on the influence of the glass fiber length on the strength and other aspects of the denitration catalyst.

[0004] At present, the glass fibers obtained from the recycling of a large number of waste materials show the phenomenon of irregular lengths and cannot reach a uniform length. The prior art can only utilize fibers of a specific length, and the utilization of recycled fibers is insufficient. Therefore, how to apply glass fibers of different lengths to the field of denitration catalysts is the focus of current research. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art that the glass fibers in the denitration catalyst need to have a single length, the utilization of fibers of different lengths is relatively narrow, and the glass fibers obtained from the recycling of existing waste materials are irregular in length and difficult to realize resource utilization. The present invention provides a method for preparing a denitration catalyst by using stepped fibers and a denitration catalyst. By exploring the gradation of glass fibers of different lengths, the present invention can realize the utilization of glass fibers of various sizes, thereby effectively expanding the application range of glass fibers and improving the overall performance of the product.

[0006] To achieve the above purpose, on the one hand, the present invention provides a method for preparing a denitration catalyst by using stepped fibers, and the method includes the following steps:

[0007] (1) Mix glass fiber A, organic solvent A, water and polymer A to obtain pretreated glass fiber A; mix glass fiber B, organic solvent B, water and polymer B to obtain pretreated glass fiber B; react glass fiber C with an aqueous organic acid solution to obtain pretreated glass fiber C; soak glass fiber D in a first polyacrylamide aqueous solution to obtain pretreated glass fiber D; soak glass fiber E in a second polyacrylamide aqueous solution to obtain pretreated glass fiber E;

[0008] (2) Mix titanium dioxide, pretreated glass fiber A, and organic solvent C to obtain modified titanium dioxide; mix tungsten source, modified titanium dioxide, vanadium source, C1-C10 alcohol compounds, and aqueous ammonia solution to obtain a titanium-tungsten-vanadium mixture;

[0009] (3) Knead pretreated glass fiber B, titanium-tungsten-vanadium mixture, lubricant, pretreated glass fiber C, pretreated glass fiber D, binder, plasticizer, and pretreated glass fiber E, and then carry out aging, extrusion molding, and sintering;

[0010] Among them, polymer A and polymer B are each independently selected from polyethylene oxide and / or polyacrylamide;

[0011] The length La of glass fiber A ranges from 0.5 mm ≤ La < 1 mm, the length Lb of glass fiber B ranges from 1 mm ≤ Lb < 3 mm, the length Lc of glass fiber C ranges from 3 mm ≤ Lc < 5 mm, the length Ld of glass fiber D ranges from 5 mm ≤ Ld < 7 mm, and the length Le of glass fiber E ranges from 7 mm ≤ Le ≤ 9 mm;

[0012] Based on the total weight of the glass fiber, the content of glass fiber C is 45-70 wt%.

[0013] Preferably, based on the total weight of the glass fiber, the content of glass fiber A is 5-15 wt%, the content of glass fiber B is 10-25 wt%, the content of glass fiber C is 45-70 wt%, the content of glass fiber D is 10-25 wt%, and the content of glass fiber E is 5-15 wt%.

[0014] Preferably, the ratio of the total weight of the glass fiber to the weight of titanium dioxide is 5-15:100, where the glass fiber is calculated as SiO2.

[0015] Preferably, in step (1), organic solvent A and organic solvent B are each independently selected from one or more of C1-C5 alcohol compounds, acetone, and dimethyl ether.

[0016] Preferably, in step (1), the organic acid is selected from one or more of citric acid, tartaric acid, oxalic acid, acetic acid, ethylenediaminetetraacetic acid, hydroxyethylethylenediphosphonic acid, aminotrimethylphosphinic acid, and ethylenediaminetetramethylphosphinic acid; and / or

[0017] The concentration of the aqueous organic acid solution ≤ 0.1 mol / L.

[0018] Preferably, the specific process of step (2) includes:

[0019] (2.1) Mix titanium dioxide, pretreated glass fiber A, and organic solvent C to obtain modified titanium dioxide;

[0020] (2.2) Mix the tungsten source, modified titanium dioxide, and the first aqueous ammonia solution, and then perform ball milling to obtain a titanium-tungsten mixture.

[0021] (2.3) Mix the titanium-tungsten mixture, vanadium source, C1-C10 alcohol compound, and the second aqueous ammonia solution to obtain a titanium-tungsten-vanadium mixture.

[0022] Preferably, in step (2.2), the weight ratio of the amount of the tungsten source to the titanium dioxide is 2.5-5 wt:100, where the tungsten source is calculated as WO3; and / or

[0023] In step (2.3), the weight ratio of the amount of the vanadium source to the titanium dioxide is 0.8-1.5 wt:100, where the vanadium source is calculated as V2O5; and / or

[0024] In step (2.3), the C1-C10 alcohol compound is selected from one or more of monoethanolamine, diethanolamine, triethanolamine, diethylene glycol, glycerol, diglycerol, triglycerol, and triisopropanolamine.

[0025] Preferably, the specific process of step (3) includes:

[0026] (3.1) Knead the pretreated glass fiber B, the titanium-tungsten-vanadium mixture, and part of the lubricant.

[0027] (3.2) Knead the material obtained in step (3.1), the pretreated glass fiber C, the pretreated glass fiber D, the binder, and the plasticizer.

[0028] (3.3) Knead the material obtained in step (3.2), the pretreated glass fiber E, and the remaining lubricant, and then perform aging, extrusion molding, and sintering.

[0029] Preferably, the lubricant is selected from one or more of glycerol, triethanolamine, and stearic acid; and / or

[0030] The plasticizer is selected from phthalic acid and / or dioctyl phthalate; and / or

[0031] The binder is selected from one or more of polyvinyl alcohol, methyl cellulose, hydroxymethyl cellulose, polyacrylamide, and polyethylene glycol.

[0032] The second aspect of the present invention provides a denitration catalyst prepared by the method described above.

[0033] The method described in the present invention can achieve the gradient utilization of glass fibers. Different lengths of glass fibers can be simultaneously applied to the preparation of denitration catalysts, which can lay a foundation for the subsequent recovery of glass fibers with different lengths. At the same time, the denitration catalyst prepared by the method described in the present invention has a certain improvement in mechanical strength on the basis of excellent denitration performance. Detailed Description of the Invention

[0034] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0036] On the one hand, the present invention provides a method for preparing a denitration catalyst using stepped fibers, and the method includes the following steps:

[0037] (1) Mix glass fiber A, organic solvent A, water, and polymer A to obtain pretreated glass fiber A; mix glass fiber B, organic solvent B, water, and polymer B to obtain pretreated glass fiber B; react glass fiber C with an aqueous organic acid solution to obtain pretreated glass fiber C; soak glass fiber D in a first polyacrylamide aqueous solution to obtain pretreated glass fiber D; soak glass fiber E in a second polyacrylamide aqueous solution to obtain pretreated glass fiber E;

[0038] (2) Mix titanium dioxide, pretreated glass fiber A, and organic solvent C to obtain modified titanium dioxide; mix a tungsten source, modified titanium dioxide, a vanadium source, C1-C10 alcohol compounds, and an ammonia aqueous solution to obtain a titanium-tungsten-vanadium mixture;

[0039] (3) Knead pretreated glass fiber B, the titanium-tungsten-vanadium mixture, a lubricant, pretreated glass fiber C, pretreated glass fiber D, a binder, a plasticizer, and pretreated glass fiber E, and then carry out aging, extrusion molding, and sintering;

[0040] Wherein, polymer A and polymer B are each independently selected from polyethylene oxide and / or polyacrylamide;

[0041] The length La of glass fiber A ranges from 0.5 mm ≤ La < 1 mm, the length Lb of glass fiber B ranges from 1 mm ≤ Lb < 3 mm, the length Lc of glass fiber C ranges from 3 mm ≤ Lc < 5 mm, the length Ld of glass fiber D ranges from 5 mm ≤ Ld < 7 mm, and the length Le of glass fiber E ranges from 7 mm ≤ Le ≤ 9 mm;

[0042] Based on the total weight of the glass fibers, the content of glass fiber C is 45 - 70 wt%.

[0043] In a preferred embodiment, based on the total weight of the glass fibers, the content of glass fiber A is 5 - 15 wt%, the content of glass fiber B is 10 - 25 wt%, the content of glass fiber C is 45 - 70 wt%, the content of glass fiber D is 10 - 25 wt%, and the content of glass fiber E is 5 - 15 wt%. In the present invention, the total weight of the glass fibers refers to the total weight of glass fiber A, glass fiber B, glass fiber C, glass fiber D, and glass fiber E.

[0044] The method described in the present invention realizes the simultaneous utilization of glass fibers of different lengths in the preparation process of the denitration catalyst. It can not only promote the resource utilization of recycled glass fibers, but also further improve the mechanical properties of the prepared denitration catalyst by optimizing the ratio of glass fibers of different lengths.

[0045] Further preferably, based on the total weight of the glass fibers, the content of glass fiber A ≤ the content of glass fiber D.

[0046] Further preferably, based on the total weight of the glass fibers, the content of glass fiber E ≤ the content of glass fiber B.

[0047] In order to further improve the mechanical strength and denitration performance of the denitration catalyst, in a preferred embodiment, the ratio of the total weight of the glass fibers to the weight of titanium dioxide is 5 - 15:100, where the glass fibers are calculated as SiO2; specifically, it can be 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, or 15:100.

[0048] In the present invention, in step (1), adding a non-acidic water-soluble organic substance and a small amount of polymer to glass fiber A and glass fiber B respectively for treatment can improve the overall dispersion degree of the fibers. Preferably, the weight-average molecular weight of polyethylene oxide is 1000-20000; the weight-average molecular weight of polyacrylamide is 500-20000. In a preferred case, organic solvent A and organic solvent B are each independently selected from one or more of C1-C5 alcohol compounds, acetone, and dimethyl ether; specifically, the C1-C5 alcohol compounds can be methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, or glycerol.

[0049] In a preferred embodiment, in step (1), the process of obtaining pretreated glass fiber A includes: mixing glass fiber A, organic solvent A, water, and polymer A, and then performing solid-liquid separation, washing, and drying. Further preferably, the liquid-solid ratio of organic solvent A to glass fiber A is 10-20 mL:1 g, the liquid-solid ratio of water to glass fiber A is 5-20 mL:1 g; the weight ratio of polymer A to glass fiber A is 0.5-2:10; the mixing conditions include: the temperature is 30-60 °C, and the time is 30-120 min.

[0050] In a preferred embodiment, in step (1), the process of obtaining pretreated glass fiber B includes: mixing glass fiber B, water, organic solvent B, and polymer B, and then performing solid-liquid separation, washing, and drying. Further preferably, the liquid-solid ratio of organic solvent B to glass fiber B is 10-20 mL:1 g, the liquid-solid ratio of water to glass fiber B is 5-20 mL:1 g; the weight ratio of polymer B to glass fiber B is 0.5-2:10, and the mixing conditions include: the temperature is 60-90 °C, and the time is 30-120 min.

[0051] In a preferred embodiment, in step (1), the organic acid is selected from one or more of citric acid, tartaric acid, oxalic acid, acetic acid, ethylenediaminetetraacetic acid, hydroxyethylethylenediphosphonic acid, aminotrimethylphosphonic acid, and ethylenediaminetetramethylphosphonic acid, more preferably citric acid, tartaric acid, or oxalic acid. The concentration of the aqueous organic acid solution ≤ 0.1 mol / L, further preferably 0.03-0.08 mol / L.

[0052] In a preferred embodiment, when glass fiber C is mixed with the aqueous organic acid solution for reaction in step (1), the reaction temperature ≤ 40 °C, more preferably 20-30 °C; the reaction time is 10-90 min; the liquid-solid ratio of the aqueous organic acid solution to glass fiber C is 5-20 mL:1 g.

[0053] In a preferred embodiment, in step (1), the soaking time of glass fiber D in the first polyacrylamide aqueous solution is 30 - 120 min, the concentration of the first polyacrylamide aqueous solution is 2 - 8 wt%, and the liquid-solid ratio of the first polyacrylamide aqueous solution to glass fiber D is 5 - 20 mL:1 g.

[0054] In a preferred embodiment, in step (1), the soaking time of glass fiber E in the second polyacrylamide aqueous solution is 30 - 120 min, the concentration of the second polyacrylamide aqueous solution is 2 - 8 wt%, and the liquid-solid ratio of the second polyacrylamide aqueous solution to glass fiber D is 5 - 20 mL:1 g.

[0055] In a preferred embodiment, the specific process of step (2) includes:

[0056] (2.1) Mix titanium dioxide, pretreated glass fiber A and organic solvent C to obtain modified titanium dioxide;

[0057] (2.2) Mix tungsten source, modified titanium dioxide and the first ammonia aqueous solution and then carry out ball milling to obtain a titanium-tungsten mixture;

[0058] (2.3) Mix the titanium-tungsten mixture, vanadium source, C1 - C10 alcohol compounds and the second ammonia aqueous solution to obtain a titanium-tungsten-vanadium mixture.

[0059] In a preferred case, in step (2), the weight ratio of the tungsten source to the titanium dioxide is 2.5 - 5:100, where the tungsten source is calculated as WO3; specifically, it can be 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100 or 5:100. In the present invention, the tungsten source can be ammonium metatungstate or ammonium paratungstate.

[0060] In a preferred case, in step (2.1), organic solvent C can be C1 - C5 alcohol compounds, such as ethylene glycol; the mixing temperature is 40 - 90 °C, the mixing time is 30 - 60 min, and centrifugal separation is carried out after mixing.

[0061] In a preferred case, in step (2.2), the ball milling conditions include: the rate is 500 - 1000 r / min, the time is 20 - 40 min; the concentration of the first ammonia aqueous solution is 3 - 7 wt%. There is no special requirement for the amount of the first ammonia aqueous solution, and it can be put into use according to the conventional amount in the art. Preferably, the liquid-solid ratio of the first ammonia aqueous solution to the solid materials (tungsten source and modified titanium dioxide) is 5 - 10 mL:1 g.

[0062] In a preferred case, in step (2), the weight ratio of the amount of vanadium source to that of titanium dioxide is 0.8 - 1.5:100, where the vanadium source is calculated as V2O5; specifically, it can be 0.8:100, 0.9:100, 1:100, 1.1:100, 1.2:100, 1.3:100, 1.4:100 or 1.5:100.

[0063] In a preferred case, in step (2.3), the concentration of the second ammonia aqueous solution is 3 - 7 wt%. Further preferably, the concentration and volume of the second ammonia aqueous solution are the same as those of the first ammonia aqueous solution.

[0064] In the present invention, the C1 - C10 alcohol compound refers to a compound having 1 - 10 carbon atoms and a hydroxyl group. In a preferred case, in step (2.3), the C1 - C10 alcohol compound is selected from one or more of monoethanolamine, diethanolamine, triethanolamine, diethylene glycol, glycerol, diglycerol, triglycerol and triisopropanolamine. In a preferred case, the volume ratio of the C1 - C10 alcohol compound to the volume of the first ammonia aqueous solution is 1:10 - 20.

[0065] In a preferred embodiment, the specific process of step (3) includes:

[0066] (3.1) Kneading the pretreated glass fiber B, the titanium - tungsten - vanadium mixture and part of the lubricant;

[0067] (3.2) Kneading the material obtained in step (3.1), the pretreated glass fiber C, the pretreated glass fiber D, the binder and the plasticizer;

[0068] (3.3) Kneading the material obtained in step (3.2), the pretreated glass fiber E and the remaining lubricant, then aging, extrusion molding and sintering.

[0069] In a preferred case, in step (3.1), the amount of the lubricant used is 5 - 10 wt% of the total amount of the lubricant.

[0070] In a preferred case, in step (3.1), the kneading temperature is 150 - 200 °C and the kneading time is 0.5 - 3 h.

[0071] In a preferred case, in step (3.2), the kneading temperature is 150 - 200 °C and the kneading time is 0.5 - 3 h.

[0072] In a preferred case, in step (3.3), the kneading temperature is 180 - 220 °C and the kneading time is 0.5 - 3 h.

[0073] Preferably, the lubricant is selected from one or more of glycerol, triethanolamine, and stearic acid; the plasticizer is selected from phthalic acid and / or dioctyl phthalate; the binder is selected from one or more of polyvinyl alcohol, methyl cellulose, hydroxymethyl cellulose, polyacrylamide, and polyethylene glycol.

[0074] In a preferred embodiment, the aging time is 20 - 30 h.

[0075] In the present invention, in step (3.3), the extrusion molding and sintering can be carried out according to the conventional conditions in the art. For example, the sintering temperature can be 400 - 600 °C, and the sintering time is 2 - 5 h.

[0076] In the present invention, there are no special requirements for the dosages of the lubricant, binder, and plasticizer, and they can be used according to the conventional addition amounts in the art. Specifically, the weight ratio of titanium dioxide, lubricant, binder, and plasticizer is 1:0.05:0.1:0.06 - 0.1:0.07 - 0.1.

[0077] The second aspect of the present invention provides a denitration catalyst prepared by the method described above.

[0078] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0079] Example 1

[0080] (1) Glass fiber A, organic solvent A (glycerol), water, and polymer A (polyethylene oxide, weight average molecular weight 1500 - 2000) are mixed, and then centrifuged, washed, and dried to obtain pretreated glass fiber A; wherein, the liquid - solid ratio of organic solvent A to glass fiber A is 10 mL:1 g, the liquid - solid ratio of water to glass fiber A is 10 mL:1 g, the weight ratio of polymer A to glass fiber A is 1:10, the mixing temperature is 50 °C, and the mixing time is 60 min.

[0081] Glass fiber B, water, organic solvent B (glycerol), and polymer B (polyethylene oxide, weight average molecular weight 1500 - 2000) are mixed, and then solid - liquid separated, washed, and dried to obtain pretreated glass fiber B; wherein, the liquid - solid ratio of organic solvent B to glass fiber B is 10 mL:1 g, the liquid - solid ratio of water to glass fiber B is 10 mL:1 g, the weight ratio of polymer B to glass fiber B is 1:10, the mixing temperature is 70 °C, and the mixing time is 60 min.

[0082] Mix glass fiber C with an aqueous solution of organic acid (0.06 mol / L citric acid aqueous solution) for reaction, then perform solid-liquid separation, washing, and drying to obtain pretreated glass fiber C; wherein, the mixing temperature is 25 °C, the time is 30 min, and the liquid-solid ratio of the aqueous solution of organic acid to glass fiber C is 15 mL:1 g;

[0083] Soak glass fiber D in the first polyacrylamide aqueous solution (concentration 5 wt%) for 60 min, then perform solid-liquid separation, washing, and drying to obtain pretreated glass fiber D; wherein, the liquid-solid ratio of the first polyacrylamide aqueous solution to glass fiber D is 10 mL:1 g;

[0084] Soak glass fiber E in the first polyacrylamide aqueous solution (concentration 5 wt%) for 60 min, then perform solid-liquid separation, washing, and drying to obtain pretreated glass fiber E; wherein, the liquid-solid ratio of the second polyacrylamide aqueous solution to glass fiber D is 10 mL:1 g;

[0085] (2) Mix titanium dioxide, pretreated glass fiber A, and an excessive amount of organic solvent C (ethylene glycol), then perform solid-liquid separation, washing, and drying to obtain modified titanium dioxide; wherein, the mixing temperature is 60 °C and the time is 30 min;

[0086] Mix a tungsten source (ammonium metatungstate) and a first aqueous ammonia solution (concentration 5 wt%), then add the modified titanium dioxide, and then perform ball milling to obtain a titanium-tungsten mixture; wherein, the ball milling rate is 800 r / min and the ball milling time is 30 min; the weight ratio of the tungsten source to the amount of titanium dioxide used is 3:100, with the tungsten source calculated as WO3; the volume ratio of the first aqueous ammonia solution to the sum of the weights of the tungsten source and the modified titanium dioxide is 10 mL:1 g;

[0087] Mix the titanium-tungsten mixture, a vanadium source (ammonium metavanadate), an alcohol compound (monoethanolamine), and a second aqueous ammonia solution (concentration 5 wt%), then perform solid-liquid separation, washing, and drying to obtain a titanium-tungsten-vanadium mixture; wherein, the weight ratio of the vanadium source to the amount of titanium dioxide used is 1.05:100, with the vanadium source calculated as V2O5; the volume of the second aqueous ammonia solution is the same as that of the first aqueous ammonia solution; the volume ratio of the alcohol compound to the first aqueous ammonia solution is 1:15;

[0088] (3.1) Knead pretreated glass fiber B, the titanium-tungsten-vanadium mixture, and a lubricant (triethanolamine) accounting for 5 wt% of the total amount; wherein, the kneading temperature is 180 °C and the kneading time is 1 h;

[0089] (3.2) Knead the material obtained in step (3.1), pretreated glass fiber C, pretreated glass fiber D, binder (polyvinyl alcohol), and plasticizer (phthalic acid); among them, the kneading temperature is 180 °C and the kneading time is 1 h;

[0090] (3.3) Knead the material obtained in step (3.2), pretreated glass fiber E and the remaining lubricant, then carry out aging, extrusion molding and sintering; among them, the kneading temperature is 200 °C, the kneading time is 1 h, the aging time is 24 h, the sintering temperature is 500 °C, and the sintering time is 4 h;

[0091] The range of the length La of glass fiber A is 0.5 mm ≤ La < 1 mm, the range of the length Lb of glass fiber B is 1 mm ≤ Lb < 3 mm, the range of the length Lc of glass fiber C is 3 mm ≤ Lc < 5 mm, the range of the length Ld of glass fiber D is 5 mm ≤ Ld < 7 mm, and the range of the length Le of glass fiber E is 7 mm ≤ Le ≤ 9 mm;

[0092] Based on the total weight of the glass fiber, the content of glass fiber A is 6 wt%, the content of glass fiber B is 14 wt%, the content of glass fiber C is 57 wt%, the content of glass fiber D is 15 wt%, and the content of glass fiber E is 8 wt%;

[0093] The ratio of the total weight of the glass fiber to the weight of titanium dioxide is 11:100, where the glass fiber is calculated as SiO2;

[0094] The weight ratio of the amounts of titanium dioxide, lubricant, binder and plasticizer is 1:0.08:0.08:0.09.

[0095] Example 2

[0096] Implement according to the method described in Example 1, the difference is that, based on the total weight of the glass fiber, the content of glass fiber A is 10 wt%, the content of glass fiber B is 15 wt%, the content of glass fiber C is 55 wt%, the content of glass fiber D is 14 wt%, and the content of glass fiber E is 6 wt%.

[0097] Example 3

[0098] Implement according to the method described in Example 1, the differences are: one is to adjust the pretreatment process of glass fiber A, glass fiber B and glass fiber C in step (1); the other is to adjust the content of each component in the glass fiber.

[0099] Specifically:

[0100] Mix glass fiber A, organic solvent A (ethylene glycol), water, and polymer A (polyacrylamide with a weight-average molecular weight of 1500 - 2000), then perform centrifugal separation, washing, and drying to obtain pretreated glass fiber A; among them, the liquid-solid ratio of organic solvent A to glass fiber A is 10 mL:1 g, the liquid-solid ratio of water to glass fiber A is 10 mL:1 g, the weight ratio of polymer A to glass fiber A is 1:10, the mixing temperature is 50 °C, and the mixing time is 60 min;

[0101] Mix glass fiber B, water, organic solvent B (ethylene glycol), and polymer B (polyacrylamide with a weight-average molecular weight of 1500 - 2000), then perform solid-liquid separation, washing, and drying to obtain pretreated glass fiber B; among them, the liquid-solid ratio of organic solvent B to glass fiber B is 10 mL:1 g, the liquid-solid ratio of water to glass fiber B is 10 mL:1 g, the weight ratio of polymer B to glass fiber B is 1:10, the mixing temperature is 60 °C, and the mixing time is 60 min;

[0102] Based on the total weight of the glass fibers, the content of glass fiber A is 10 wt%, the content of glass fiber B is 15 wt%, the content of glass fiber C is 55 wt%, the content of glass fiber D is 14 wt%, and the content of glass fiber E is 6 wt%.

[0103] Comparative Example 1

[0104] Carry out the implementation according to the method described in Example 1, the difference is that the lengths of glass fibers A - E are all 3 - 5 mm.

[0105] Comparative Example 2

[0106] Carry out the implementation according to the method described in Example 1, the difference is that all glass fibers are directly put into use without pretreatment.

[0107] Specifically, the preparation process of the catalyst is as follows:

[0108] (1) Mix titanium dioxide, glass fiber A, and an excessive amount of organic solvent C (ethylene glycol), then perform solid-liquid separation, washing, and drying to obtain modified titanium dioxide; among them, the mixing temperature is 60 °C and the time is 30 min;

[0109] Mix the tungsten source (ammonium metatungstate) and the first ammonia water solution (concentration of 5 wt%), then add the modified titanium dioxide, and then carry out ball milling to obtain a titanium-tungsten mixture; among them, the ball milling rate is 800 r / min and the ball milling time is 30 min; the weight ratio of the tungsten source to the amount of titanium dioxide used is 3:100, and the tungsten source is calculated as WO3; the volume ratio of the first ammonia water solution to the sum of the weights of the tungsten source and the modified titanium dioxide is 10 mL:1 g;

[0110] Mix the titanium-tungsten mixture, vanadium source (ammonium metavanadate), alcohol compound (monoethanolamine), and second aqueous ammonia solution (concentration 5 wt%) and then perform solid-liquid separation, washing, and drying to obtain a titanium-tungsten-vanadium mixture; wherein, the weight ratio of the vanadium source to the titanium dioxide is 1.05:100, with the vanadium source calculated as V2O5; the volume of the second aqueous ammonia solution is the same as the volume of the first aqueous ammonia solution; the volume ratio of the alcohol compound to the first aqueous ammonia solution is 1:15;

[0111] (2.1) Knead glass fiber B, the titanium-tungsten-vanadium mixture, and a total of 5 wt% lubricant (triethanolamine); wherein, the kneading temperature is 180 °C and the kneading time is 1 h;

[0112] (2.2) Knead the material obtained in step (2.1), glass fiber C, glass fiber D, binder (polyvinyl alcohol), and plasticizer (phthalic acid); wherein, the kneading temperature is 180 °C and the kneading time is 1 h;

[0113] (2.3) Knead the material obtained in step (2.2), glass fiber E, and the remaining lubricant, then carry out aging, extrusion molding, and sintering; wherein, the kneading temperature is 200 °C, the kneading time is 1 h, the aging time is 24 h, the sintering temperature is 500 °C, and the sintering time is 4 h;

[0114] The range of the length La of glass fiber A is 0.5 mm ≤ La < 1 mm, the range of the length Lb of glass fiber B is 1 mm ≤ Lb < 3 mm, the range of the length Lc of glass fiber C is 3 mm ≤ Lc < 5 mm, the range of the length Ld of glass fiber D is 5 mm ≤ Ld < 7 mm, and the range of the length Le of glass fiber E is 7 mm ≤ Le ≤ 9 mm;

[0115] Based on the total weight of the glass fibers, the content of glass fiber A is 6 wt%, the content of glass fiber B is 14 wt%, the content of glass fiber C is 57 wt%, the content of glass fiber D is 15 wt%, and the content of glass fiber E is 8 wt%;

[0116] The ratio of the total weight of the glass fibers to the weight of the titanium dioxide is 11:100, wherein the glass fibers are calculated as SiO2;

[0117] The weight ratio of the titanium dioxide, lubricant, binder, and plasticizer is 1:0.08:0.08:0.09.

[0118] Comparative Example 3

[0119] The method described in Example 1 was implemented, except that, based on the total weight of the glass fibers, the content of glass fiber A was 55 wt%, the content of glass fiber B was 15 wt%, the content of glass fiber C was 10 wt%, the content of glass fiber D was 14 wt%, and the content of glass fiber E was 6 wt%.

[0120] Comparative Example 4

[0121] The method described in Example 1 was implemented, except that, based on the total weight of the glass fibers, the content of glass fiber A was 10 wt%, the content of glass fiber B was 15 wt%, the content of glass fiber C was 6 wt%, the content of glass fiber D was 14 wt%, and the content of glass fiber E was 55 wt%.

[0122] Test Example

[0123] 1. A TYE-300 type pressure testing machine was used to test the axial compressive strength and longitudinal compressive strength of the denitration catalysts obtained in Examples 1 - 3 and the products obtained in Comparative Examples 1 - 7. The range of the pressure testing machine was 300 KN, and the pressurization rate was 250 N / s. The test results are shown in Table 1.

[0124] 2. The abrasion resistance of the denitration catalysts obtained in Examples 1 - 3 and the products obtained in Comparative Examples 1 - 4 was tested; the results are shown in the table.

[0125] Test method: The sample to be tested was divided into two parts, which were used as the test sample and the reference sample respectively. The test sample and the reference sample were dried in an oven at 105°C for 2 h, and after natural cooling, the weights of the test sample and the reference sample were weighed; then the test sample and the reference sample were placed in the test chamber and the reference chamber of the abrasion test device respectively. The test sample and the reference sample were completely sealed with ceramic fiber paper between them and the chamber walls. Then, air containing an abrasive was passed through the test sample at a certain flow rate, and air was passed through the reference sample at the same flow rate. After 2 hours of abrasion, the weights of the abraded test sample, the reference sample, and the abrasive were weighed to calculate the abrasion strength.

[0126] The specific calculation method is as follows:

[0127]

[0128] Among them, ξ h represents the abrasion strength, % / kg;

[0129] W1 represents the weight of the test sample before the test, kg;

[0130] W2 represents the weight of the test sample after the test, kg;

[0131] W3 represents the weight of the reference sample before the test, kg;

[0132] W4 represents the weight after the reference sample test, kg;

[0133] W represents the recorded weight of the abrasives, kg.

[0134] 3. The denitrification rates of the denitrification catalysts obtained from Test Examples 1-3 and the products obtained from Comparative Examples 1-4 for nitrogen oxides;

[0135] Test method: Test the denitrification rate of nitrogen oxides of the denitrification catalyst at different temperatures: The test method is to take small samples of the denitrification catalyst and the product and place them into the catalyst performance evaluation reaction device, and introduce a simulated gas for activity evaluation. The composition of the simulated gas is similar to that of the industrial boiler tail gas, and its composition is as follows: 500 ppm of NO, 400 ppm of NH3, 10.00% of O2, 12% of water, and the rest is nitrogen. Introduce the simulated gas into the denitrification reactor for reaction. The reaction temperature is 210 °C. The concentrations of nitrogen oxides in the flue gas before and after the reaction are analyzed using a 42i-HL flue gas analyzer, and then the denitrification rate of the denitrification catalyst at a reaction temperature of 210 °C is calculated. The test results are shown in Table 2;

[0136] Adjust the reaction temperature in the denitrification reactor to 270 °C to obtain the denitrification rate of the denitrification catalyst at a reaction temperature of 270 °C. The test results are shown in Table 2;

[0137] The calculation method of the denitrification rate of the denitrification catalyst is: η = (a - b) / a × 100%, where the concentration of nitrogen oxides in the flue gas before the reaction is a, the concentration of nitrogen oxides in the flue gas after the reaction is b, and the denitrification rate of the denitrification catalyst is η.

[0138] Table 1

[0139]

[0140] Table 2

[0141]

[0142]

[0143] Combining the data in Table 1 and Table 2, it can be seen that the denitrification catalyst with high compressive strength, good wear resistance and high denitrification efficiency can be prepared by using the method of the present invention.

[0144] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing a denitration catalyst using stepped fibers, characterized in that, The method includes the following steps: (1) Mix glass fiber A, organic solvent A, water, and polymer A to obtain pretreated glass fiber A; mix glass fiber B, organic solvent B, water, and polymer B to obtain pretreated glass fiber B; react glass fiber C with an aqueous organic acid solution to obtain pretreated glass fiber C; soak glass fiber D in a first polyacrylamide aqueous solution to obtain pretreated glass fiber D; soak glass fiber E in a second polyacrylamide aqueous solution to obtain pretreated glass fiber E; (2) Mix titanium dioxide, pretreated glass fiber A, and organic solvent C to obtain modified titanium dioxide; mix a tungsten source, the modified titanium dioxide, a vanadium source, C1-C10 alcohol compounds, and an aqueous ammonia solution to obtain a titanium-tungsten-vanadium mixture; (3) Knead pretreated glass fiber B, the titanium-tungsten-vanadium mixture, a lubricant, pretreated glass fiber C, pretreated glass fiber D, a binder, a plasticizer, and pretreated glass fiber E, and then carry out aging, extrusion molding, and sintering; wherein, polymer A and polymer B are each independently selected from polyethylene oxide and / or polyacrylamide; The length La of glass fiber A ranges from 0.5 mm ≤ La < 1 mm, the length Lb of glass fiber B ranges from 1 mm ≤ Lb < 3 mm, the length Lc of glass fiber C ranges from 3 mm ≤ Lc < 5 mm, the length Ld of glass fiber D ranges from 5 mm ≤ Ld < 7 mm, and the length Le of glass fiber E ranges from 7 mm ≤ Le ≤ 9 mm; Based on the total weight of the glass fibers, the content of glass fiber A is 5-15 wt%, the content of glass fiber B is 10-25 wt%, the content of glass fiber C is 45-70 wt%, the content of glass fiber D is 10-25 wt%, and the content of glass fiber E is 5-15 wt%.

2. The method according to claim 1, wherein The ratio of the total weight of the glass fibers to the weight of titanium dioxide is 5-15:100, wherein the glass fibers are calculated as SiO2.

3. The method according to claim 1, characterized in that, In step (1), organic solvent A and organic solvent B are each independently selected from one or more of C1-C5 alcohol compounds, acetone, and dimethyl ether.

4. The method according to claim 1 or 3, characterized in that, In step (1), the organic acid is selected from one or more of citric acid, tartaric acid, oxalic acid, acetic acid, ethylenediaminetetraacetic acid, hydroxyethylidene diphosphonic acid, aminotrimethyl phosphonic acid, and ethylenediaminetetramethyl phosphonic acid; and / or The concentration of the aqueous organic acid solution ≤ 0.1 mol / L.

5. The method according to claim 1 or 2, characterized in that, The specific process of step (2) includes: (2.1) Mix titanium dioxide, pretreated glass fiber A, and organic solvent C to obtain modified titanium dioxide; (2.2) Mix the tungsten source, the modified titanium dioxide, and a first aqueous ammonia solution and then carry out ball milling to obtain a titanium-tungsten mixture; (2.3) Mix the titanium-tungsten mixture, the vanadium source, C1-C10 alcohol compounds, and a second aqueous ammonia solution to obtain a titanium-tungsten-vanadium mixture.

6. The method according to claim 1, wherein In step (2), the weight ratio of the tungsten source to the amount of titanium dioxide used is 2.5-5:100, wherein the tungsten source is calculated as WO3; and / or In step (2), the weight ratio of the dosage of the vanadium source to that of the titanium dioxide is 0.8-1.5:100, where the vanadium source is calculated as V2O5; and / or In step (2), the C1-C10 alcohol compound is selected from one or more of monoethanolamine, diethanolamine, triethanolamine, diethylene glycol, glycerol, diglycerol, triglycerol, and triisopropanolamine.

7. The method according to claim 1, wherein The specific process of step (3) includes: (3.1) Kneading the pretreated glass fiber B, the titanium-tungsten-vanadium mixture, and part of the lubricant; (3.2) Kneading the material obtained in step (3.1), the pretreated glass fiber C, the pretreated glass fiber D, the binder, and the plasticizer; (3.3) Kneading the material obtained in step (3.2), the pretreated glass fiber E, and the remaining lubricant, followed by aging, extrusion molding, and sintering.

8. The method according to claim 1 or 7, characterized in that The lubricant is selected from one or more of glycerol, triethanolamine, and stearic acid; and / or The plasticizer is selected from phthalic acid and / or dioctyl phthalate; and / or The binder is selected from one or more of polyvinyl alcohol, methyl cellulose, hydroxymethyl cellulose, polyacrylamide, and polyethylene glycol.

9. A denitrification catalyst prepared by the method according to any one of claims 1-8.

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