CN113996309B

CN113996309B - Preparation method of high-strength SCR catalyst for CO-removal

Info

Publication number: CN113996309B
Application number: CN202111402208.2A
Authority: CN
Inventors: 徐光辉; 贾曼; 陆金丰; 白伟; 杨建辉; 张胜浩; 李京徽; 张磊
Original assignee: Guoneng Longyuan Catalyst Jiangsu Co ltd; Guoneng Longyuan Environmental Protection Co Ltd
Current assignee: Guoneng Longyuan Catalyst Jiangsu Co ltd; Guoneng Longyuan Environmental Protection Co Ltd
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2023-12-26
Anticipated expiration: 2041-11-23
Also published as: CN113996309A

Abstract

The invention discloses a preparation method of a high-strength SCR catalyst for CO synergistic removal, which belongs to the field of SCR denitration catalysts, and comprises the steps of mixing an alkalization titanium tungsten powder serving as a carrier, extruding and molding a pug, performing primary drying and calcination to obtain a primary blank, cutting, dipping and hardening, carrying out load treatment, and performing secondary drying and calcination. The denitration catalyst capable of cooperatively removing CO is obtained by impregnating the end of the catalyst in impregnating solution containing one or more of copper nitrate, cobalt acetate, ammonium niobium oxalate and aluminum sulfate and 0-20% of one or more soluble salts of active components M (M is cerium, nickel or lanthanum), drying and calcining. When the low-temperature flue gas is treated, the end dipping part preferentially and selectively catalyzes and removes CO to generate exothermic reaction, so that on one hand, CO removal can be realized, and on the other hand, the flue gas temperature can be improved, and further, the activity of the rear-end SCR catalyst is improved. The catalyst end part is immersed to ensure the denitration efficiency of the catalyst, and meanwhile, the problem of high production cost of the catalyst which is completely immersed and integrally prepared can be avoided.

Description

Preparation method of high-strength SCR catalyst for CO-removal

Technical Field

The invention belongs to the field of SCR denitration catalysts, and particularly relates to a preparation method of a high-strength SCR catalyst for CO-removal.

Background

The SCR denitration catalyst is mainly applied to flue gas denitration of boilers mainly used for thermal power and related to coal and gas in various industries at present. In this regard, the combustion process of all fossil fuels inevitably involves insufficient combustion, thereby producing a large amount of CO gas. In order to avoid the waste of partial energy sources, large coal-fired and gas-fired boilers such as thermal power plants and steel plants can adopt partial flue gas circulation, secondary combustion and other technological processes and device equipment, but the low content of CO in the discharged flue gas cannot be ensured, and particularly, the load of the boiler is reduced in the peak regulation operation period of the thermal power plant, the furnace temperature is lower, and the sufficient combustion is more difficult to ensure; for smaller boilers, the process and the device are not needed, and the CO content in the flue gas is higher.

CO has strong toxicity, the higher concentration can harm the viscera and brain tissues of human body, the CO in the atmosphere can be finally converted into CO through the reaction with hydroxyl compounds when being mixed with air to form an explosive mixture ₂ 。

At present, the related researches show that the CO content in the flue gas of the thermal power plant including the supercritical opposite-flow combustion boiler and the biomass solid combustion boiler is 500-2500 mg/m ³ . Simultaneously, along with the continuous tightening of the national environmental protection policyThe national strict control of carbon emission is necessary to remove CO in the flue gas as well as NO.

Chinese patent CN 112316943A discloses a method of using coconut shell activated carbon as carrier and Cu ₂ Low-temperature CO-SCR denitration Cu with O as active component ₂ The O/AC catalyst, however, the catalyst prepared by the activated carbon in the patent has weak selectivity and poor stability, and is inconvenient for long-term industrial application. Chinese patent CN 111229212A uses manganese as an active ingredient, and copper, iron, cerium, cobalt or nickel is added to the manganese active ingredient to improve the poisoning effect of water vapor on the catalyst, and improve the competition of oxygen and nitrogen oxides on carbon monoxide, so that the carbon monoxide preferentially undergoes catalytic reduction reaction with the nitrogen oxides. However, the catalyst prepared by the patent is all active component oxide, no catalyst carrier exists, the cost is high, the reaction contact area is relatively small, and certain difficulty exists in industrial application. Chinese patent CN 113441131A adopts a modified V-Mo-Ti system catalyst as a carrier, and adds various catalytic factors. However, this patent describes a co-denitration catalyst of the integrally extruded type, which is relatively costly.

Disclosure of Invention

The invention aims to provide a preparation method of a high-strength SCR catalyst for CO synergistic removal, which takes titanium tungsten powder as a carrier, one or more of vanadium, cobalt, cerium and lanthanum as main active components, and one or more of copper, tungsten, molybdenum and niobium as auxiliary active components, so that the SCR catalyst with good denitration and CO removal performances and high mechanical strength is prepared.

Therefore, the invention provides a preparation method of a high-strength SCR catalyst for CO-removal, which comprises the following steps:

s1, pretreatment of raw materials: alkalizing the carrier component titanium tungsten powder of the SCR denitration catalyst, stirring and mixing uniformly, drying, grinding and crushing, and sieving and separating to obtain pretreated titanium tungsten powder serving as a carrier;

s2, pug mixing: during mixing, adding all soluble materials including ammonium metavanadate, ammonium heptamolybdate and cerium nitrate in a solution state, adding all insoluble/indissoluble materials including pore-forming agents, structure auxiliary agents, adhesives and lubricants in a state of crushing, dispersing and no agglomeration, uniformly mixing all materials, and finishing mixing;

s3, catalyst extrusion: extruding the pug after mixing in an extruder;

s4, primary drying and calcining: drying and calcining the extruded pug to obtain a calcined solid;

s5, cutting: removing the damaged and cracked part according to the designed size, and cutting into a strip-shaped catalyst with uniform size;

s6, end dipping: immersing one end of the cut catalyst in an immersion liquid, wherein the immersion liquid comprises 10% -20% of copper nitrate, 5% -10% of cobalt acetate, 1% -10% of ammonium niobium oxalate, one or more of 20% -25% of aluminum sulfate and 0% -10% of one or more soluble salts of an active component M, and M is cerium, nickel or lanthanum;

s7, secondary drying and calcining: drying the impregnated catalyst in the air, and then performing secondary drying and calcination;

s8, packaging: and screening the catalyst subjected to secondary calcination, removing the damaged catalyst, and packaging.

Preferably, the depth of impregnation of the catalyst in S6 is 10% to 25% of the length of the whole catalyst.

The catalyst is partially impregnated, and nickel, cobalt, lanthanum, niobium and other elements are loaded on the surface of the end of the catalyst, so that the catalyst can play a synergistic effect with cerium, molybdenum and vanadium elements in the catalyst, the removal efficiency of the catalyst on CO and NOx is improved, and meanwhile, the high cost caused by complete impregnation and integral extrusion preparation can be avoided.

Preferably, the dipping time of the catalyst in the step S6 is 20-30 minutes, the temperature of the dipping liquid is 45-55 ℃, the catalyst is taken out to stand on a grid for airing after the dipping is finished, and the catalyst is taken out for secondary drying and calcination after 20-40 minutes.

Preferably, each time the impregnation of a batch of catalyst is completed in S6, the impregnation liquid is stirred uniformly by hand or continuously by using a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

Preferably, the alkalizing agent in S1 is one or more of ammonia water, monoethanolamine, triethanolamine and pyridine, and the alkalizing agent is added in a spray form to ensure uniform alkalizing treatment of the carrier.

Preferably, the pore-forming agent is one or more of pulp, carbon powder, polyester or chinlon chopped fibers; one or more of the structure auxiliary agents of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder; the adhesive is one or more of hydroxypropyl methyl cellulose ether, carboxymethyl hydroxyethyl cellulose or phenyl cellulose; the lubricant is one or more of graphite, stearic acid, polyimide or poly-p-hydroxybenzoate.

Preferably, the mixing is completed when the moisture content of the mixed materials in S2 is 32% -35%. The water content is higher, mainly for improving the porosity of the catalyst and slowing down the dehydration drying process of the catalyst.

Preferably, the extrusion pressure in S3 is 1.5Mpa-1.8Mpa and the extrusion temperature is 30 ℃ to 35 ℃. The extrusion pressure is lower, and is mainly used for reducing the temperature and the temperature difference of pug, reducing the expansion rate after extrusion, reducing the damage rate of microstructure and improving the porosity of the catalyst. The extrusion temperature is lower, and is mainly used for reducing the temperature difference between an extruded catalyst and the environment, avoiding strong water loss, reducing the temperature difference caused by uneven heat transfer in the drying process, and avoiding collapse damage of a micro-pore structure and occurrence of macro-cracks of the catalyst.

Preferably, S4 is dried at 30-80℃for 10 hours, then calcined at 180-250℃for 6 hours and then calcined at 300-400℃for 4 hours. The calcination temperature is lower, the high-temperature calcination time is shorter, the overall calcination time is shorter, and the method mainly aims to avoid the situation of excessive calcination in secondary calcination, and simultaneously reduces the first calcination time properly and reduces the calcination temperature properly in order to reduce the energy consumption in the production process.

Preferably, S7 is dried at 80℃for 4 hours, calcined at 120-300℃for 6 hours and calcined at 400-650℃for 6 hours.

Compared with the prior art, the invention has the characteristics and beneficial effects that:

(1) The invention takes alkalization-treated titanium tungsten powder as a carrier, takes one or more of vanadium oxide, cerium oxide, molybdenum oxide and niobium oxide as active components, mixes pugs, and obtains a primary blank body through extrusion molding, primary drying and calcination, and then cuts, impregnates and hardens load treatment and secondary drying and calcination. The denitration catalyst capable of cooperatively removing CO is obtained by impregnating the end of the catalyst in impregnating solution containing one or more of copper nitrate, cobalt acetate, ammonium niobium oxalate and aluminum sulfate and 0-20% of one or more soluble salts of active components M (M is cerium, nickel or lanthanum), drying and calcining. When the product is used for low-temperature flue gas treatment, the end dipping part preferentially catalyzes and removes CO to generate exothermic reaction, so that on one hand, CO removal can be realized, and on the other hand, the flue gas temperature can be improved, and further, the activity of the rear-end SCR catalyst is improved. The catalytic removal performance of the catalyst on CO and NOx is further improved by impregnating the catalyst surface to load the components with synergistic catalytic effect. The catalyst end part is immersed to ensure the denitration efficiency of the catalyst, and meanwhile, the problem of high production cost of the catalyst which is completely immersed and integrally prepared can be avoided.

(2) The catalyst prepared by the method has flexible components, can realize the addition of metal oxide with higher content, and avoids the problems of difficult molding and low efficiency when the catalyst with high content of metal oxide is integrally prepared. Other functions such as mercury removal, arsenic removal, thallium removal and other toxic substances can be achieved by changing the composition of the added substance M.

(3) The catalyst prepared by the method can realize the removal of CO components with lower concentration in the flue gas at the front end of the SCR catalyst without adding a new device and reducing the denitration efficiency of the SCR catalyst.

(4) The catalyst provided by the invention has good denitration and CO removal performances and high mechanical strength, and can be applied to a flue gas denitration system of low-concentration CO in various industries such as power generation, chemical industry, glass, ships, steel and the like.

Detailed Description

The present invention will be further described below in order to make the technical means, innovative features, achieved objects and effects achieved by the present invention easy to understand.

The examples described herein are specific embodiments of the present invention, which are intended to illustrate the inventive concept, are intended to be illustrative and exemplary, and should not be construed as limiting the invention to the embodiments and scope of the invention. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims and specification of the present application, including those adopting any obvious substitutions and modifications to the embodiments described herein.

In order to remove CO with lower concentration in flue gas and improve the activity of the SCR catalyst, the invention designs a preparation method for the CO synergistic removal high-strength SCR catalyst, which comprises the following steps:

1. s1, pretreatment of raw materials: and (3) carrying out alkalization treatment on the carrier component titanium tungsten powder of the SCR denitration catalyst, stirring and mixing uniformly, drying, grinding and crushing, and then sieving and separating to obtain pretreated titanium tungsten powder serving as a carrier. The alkalizing agent is one or more of ammonia water, monoethanolamine, triethanolamine and pyridine, and is added in spray form. Preferably, the alkalization treatment is carried out by using ammonia water, the concentration of the ammonia water is 30 percent, the adding proportion of the ammonia water is 1L/100kg, the ammonia water is added in a spray form, and the stirring time is not less than 2 hours. The drying temperature of the titanium tungsten powder is 60-100 ℃ and the drying time is 24 hours. The dried titanium dioxide is simply crushed, screened by a 8000-mesh screen and sieved by titanium tungsten powder.

S2, pug mixing: during mixing, one or more soluble materials of ammonium metavanadate, ammonium heptamolybdate and cerium nitrate are added in a solution state, all insoluble/indissoluble materials including pore formers, structure aids, adhesives and lubricants are added in a state of being crushed, dispersed and free of agglomeration, and all materials are uniformly mixed to finish mixing. And when the water content of the mixed materials is 32-35%, the mixing is completed. The pore-forming agent is one or more of pulp, carbon powder, polyester or chinlon chopped fibers; one or more of the structure auxiliary agents of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder; the adhesive is one or more of hydroxypropyl methyl cellulose ether, carboxymethyl hydroxyethyl cellulose or phenyl cellulose; the lubricant is one or more of graphite, stearic acid, polyimide or poly-p-hydroxybenzoate.

S3, catalyst extrusion: extruding the pug after mixing in an extruder. The extrusion pressure is 1.5Mpa-1.8Mpa, and the extrusion temperature is 30 ℃ to 35 ℃.

S4, primary drying and calcining: and drying and calcining the extruded pug to obtain a calcined solid. Drying at 30-80 deg.c for 10 hr, calcining at 180-250 deg.c for 6 hr and calcining at 300-400 deg.c for 4 hr.

S5, cutting: and removing the damaged and cracked part according to the designed size, and cutting into the strip-shaped catalyst with uniform size.

S6, end dipping: one end of the cut catalyst is immersed in an immersion liquid, wherein the immersion liquid comprises 10% -20% of copper nitrate, 5% -10% of cobalt acetate, 1% -10% of ammonium niobium oxalate, one or more of 20% -25% of aluminum sulfate and 0% -20% of one or more soluble salts of active components M, and M is cerium, nickel or lanthanum. The impregnation depth is 10% -25% of the length of the whole catalyst. The soaking time is 20-30 minutes, the temperature of the soaking solution is 45-55 ℃, the catalyst is taken out after the soaking is completed and is vertically arranged on a drain net for airing, and the catalyst is taken down for secondary drying and calcining after 20-40 minutes. After the impregnation of a batch of catalyst is finished, the impregnation liquid is stirred uniformly by manpower or continuously by a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

S7, secondary drying and calcining: and drying the impregnated catalyst in the air, and then performing secondary drying and calcination. Drying at 80 deg.c for 4 hr, calcining at 120-300 deg.c for 6 hr and calcining at 400-650 deg.c for 6 hr.

The invention will be described in further detail with reference to specific embodiments, but the scope of the invention is not limited to the description.

Example 1

Spraying ammonia water and monoethanolamine onto the surface of titanium-tungsten powder in a spray mode, stirring and mixing uniformly, drying at 80 ℃, grinding and crushing, sieving with a 8000-mesh sieve, and sieving the titanium-tungsten powder.

5.31kg of screened titanium tungsten powder is added into a mixing mill, then 0.24kg of ammonium metavanadate, 0.41kg of ammonium heptamolybdate and 0.36kg of cerium nitrate are added into the mixing mill in a solution state and are preliminarily and uniformly mixed, then 125g of paper pulp, 3.12kg of silicon-aluminum ion binder, 250g of carboxymethyl hydroxyethyl cellulose and 312g of poly-p-hydroxybenzoate are sequentially added into the mixing mill and are uniformly mixed, and when the water content of the materials is 32% -35% after the materials are mixed, the mixing is completed.

Extruding the pug after mixing in an extruder. The extrusion pressure is 1.65MPa, and the extrusion temperature is between 30 ℃ and 35 ℃.

And drying and calcining the extruded pug to obtain a calcined solid. Calcining for 10 hours at 30-80 ℃ gradually heating up and drying, then calcining for 6 hours at 180-250 ℃ gradually heating up, wherein calcining for 4 hours at the maximum of 400 ℃.

And removing the damaged and cracked part according to the designed size, and cutting into the strip-shaped catalyst with uniform size. One end of the cut catalyst was immersed in an immersion liquid containing 10% copper nitrate, 8% cobalt acetate, 3% ammonium niobium oxalate, 5% lanthanum nitrate, 20% aluminum sulfate. The impregnation depth was 25% of the length of the whole catalyst. The soaking time is 5 minutes, the temperature of the soaking solution is 50 ℃, the catalyst is taken out and vertically stands on the grid for airing after the soaking is finished, and the catalyst is taken down for secondary drying and calcination after 30 minutes. After the impregnation of a batch of catalyst is finished, the impregnation liquid is stirred uniformly by manpower or continuously by a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

Drying at 80 deg.c for 4 hr, drying at 120-300 deg.c for 6 hr and calcining at 630 deg.c for 6 hr. And screening the catalyst subjected to secondary calcination, removing the damaged catalyst, and packaging.

Example 2

Spraying aqueous solution of ammonia water and triethanolamine on the surface of titanium tungsten powder in a spray mode, stirring and mixing uniformly, drying at 80 ℃, grinding and crushing, sieving with a 8000-mesh sieve, and sieving the titanium tungsten powder.

10kg of screened titanium tungsten powder is added into a mixing mill, then 0.46kg of ammonium metavanadate, 0.78kg of ammonium heptamolybdate and 0.68kg of cerium nitrate are added into the mixing mill in a solution state and are preliminarily and uniformly mixed, then 140g of nylon fiber, 100g of carbon powder, 5.88kg of glass fiber, 470g of hydroxypropyl methyl cellulose ether, 588g of stearic acid and polyimide are sequentially added into the mixing mill and are uniformly mixed, and when the water content of the materials after mixing is 32% -35%, the mixing is completed.

Extruding the pug after mixing in an extruder. The extrusion pressure is 1.80MPa, and the extrusion temperature is between 32 and 35 ℃.

And drying and calcining the extruded pug to obtain a calcined solid. Drying for 10 hours at 30-80 ℃, then drying and calcining for 6 hours at 160-250 ℃ and finally calcining for 4 hours at 400 ℃.

And removing the damaged and cracked part according to the designed size, and cutting into the strip-shaped catalyst with uniform size. One end of the cut catalyst was immersed in an immersion liquid containing 10% copper nitrate, 2% lanthanum nitrate, 5% nickel nitrate, and 20% aluminum sulfate. The impregnation depth was 15% of the length of the whole catalyst. The soaking time is 30min, the temperature of the soaking solution is 50 ℃, the catalyst is taken out and vertically stands on the grid for airing after the soaking is finished, and the catalyst is taken down for secondary drying and calcination after 30 min. After the impregnation of a batch of catalyst is finished, the impregnation liquid is stirred uniformly by manpower or continuously by a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

Drying at 80℃for 4 hours, calcining at 120℃to 300℃for 6 hours, and calcining at 500℃for 6 hours. And screening the catalyst subjected to secondary calcination, removing the damaged catalyst, and packaging.

Example 3

Spraying aqueous solution of ammonia water, dimethylamine and triethanolamine on the surface of titanium tungsten powder in a spray mode, stirring and mixing uniformly, drying at 80 ℃, grinding and crushing, sieving with a 8000-mesh sieve, and sieving the titanium tungsten powder.

Adding 8.6kg of the sieved titanium tungsten powder carrier into a mixing mill, adding 0.39kg of ammonium metavanadate and 0.68kg of ammonium heptamolybdate into the mixing mill in a solution state, primarily mixing uniformly, then sequentially adding 80g of paper pulp, 108g of polypropylene fiber, 5.06kg of glass fiber, 314g of hydroxypropyl methyl cellulose ether, 90g of phenyl cellulose, 306g of polyimide and 150g of graphite powder into the mixing mill, fully mixing uniformly, and finishing mixing when the water content of the materials is 32-35%.

Extruding the pug after mixing in an extruder. The extrusion pressure is 1.55MPa, and the extrusion temperature is 31-34 ℃.

And drying and calcining the extruded pug to obtain a calcined solid. Drying for 10 hours at 30-80 ℃, then calcining for 6 hours at 180-250 ℃ and finally calcining for 4 hours in 400.

And removing the damaged and cracked part according to the designed size, and cutting into the strip-shaped catalyst with uniform size. One end of the cut catalyst was immersed in an immersion liquid containing 5% copper nitrate, 5% nickel nitrate, 2% lanthanum nitrate, 3% ammonium niobium oxalate, 25% aluminum sulfate. The impregnation depth was 20% of the length of the whole catalyst. The soaking time is 30min, the temperature of the soaking solution is 50 ℃, the catalyst is taken out and vertically stands on the grid for airing after the soaking is finished, and the catalyst is taken down for secondary drying and calcination after 30 min. After the impregnation of a batch of catalyst is finished, the impregnation liquid is stirred uniformly by manpower or continuously by a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

Drying at 80 ℃ for 4 hours, calcining at 120-300 ℃ for 6 hours, and calcining at 630 for 6 hours. And screening the catalyst subjected to secondary calcination, removing the damaged catalyst, and packaging.

Comparative example 1

The sample of preparation example 1 was used as a control group while an experimental group was set, except that the catalyst cut in this comparative example was directly twice calcined without impregnation, and the rest was the same as in example 1.

Test examples

The finished catalysts prepared in the above examples and comparative examples were subjected to detection and evaluation. Catalyst attrition samples were prepared and attrition performance was evaluated with reference to national standard GB/T31587-2015, and the test results are shown in table 2.

The catalysts prepared in the above examples and comparative examples were cut into rectangular parallelepiped activity test samples having end faces of about 3X 3cm and a length of 30cm, and the samples were placed in a reactor for activity test. The activity test conditions were as follows: the temperature of the reaction system is 200-300 ℃, and the airspeed of the mixed gas is 4000h ^-1 Mixed gas content: NOx 180ppm,CO 100ppm,O ₂ 5％，H ₂ O10%, nitrogen as carrier gas. Each path of gas is mixed by a mass flowmeter and then enters a reactor, the reactor is a quartz tube with the inner diameter of 6cm, and the quartz tube is placed in a three-section heating vertical tube furnace for heating; and collecting and analyzing the exhaust gas at a sampling port by using a De-Chart TD-350 portable smoke analyzer. The evaluation conditions of the performance of each sample on CO and NOx are shown in Table 1, and the test results are shown in Table 3.

Catalyst pair NO _x Is a conversion rate of (2):

conversion of CO by catalyst:

TABLE 1 evaluation conditions for catalytic Performance of catalyst finished products prepared in examples

Project	Application 1	Application 2	Application 3
				Inlet flue gas NO concentration/ppm	180	180	180
Inlet flue gas CO concentration/ppm	100	100	100
				Inlet flue gas O ₂ Content/%	5	5	5
Airspeed/h ^-1	4000	4000	4000
				Molar ratio of ammonia nitrogen	1:1	1:1	1:1
Temperature/. Degree.C	200	240	280
				Reaction time/h	2	2	2

Table 2, evaluation of abrasion Properties of catalyst finished products of examples

TABLE 3 abrasion Performance detection of finished catalyst for each preparation example

Tables 2 and 3 show that the catalyst prepared by the method has the removal efficiency of over 60 percent and over 80 percent on CO and NOx under each application condition, and the removal effect is stable, wherein the sample prepared in the embodiment 1 has the optimal performance. Compared with the comparative sample, the catalyst sample prepared in the example has obviously improved wear resistance and catalytic removal performance for CO and NOx; compared with the comparative example sample, the abrasion performance of the sample in the example 1 is improved by about 40%, the catalytic performance of CO and NOx is improved by 43.4% and 9.5%, and the abrasion performance of the catalyst is improved by forming an abrasion-resistant gel layer on the surface of the catalyst by aluminum sulfate and niobium oxalate in the impregnating solution after the catalyst is impregnated by adopting M solution and forming an abrasion-resistant layer after drying and calcining. The cobalt, nickel, lanthanum, niobium and other elements are impregnated and loaded on the surface of the catalyst, so that a synergistic removal effect is formed with the original cerium, vanadium and molybdenum elements of the catalyst, and the CO and NOx removal efficiency of the catalyst is greatly improved.

The above examples are intended to illustrate the invention only and are not intended to limit the scope of the claims, but other alternatives which can be envisaged by a person skilled in the art from the teachings of the present invention shall fall within the scope of the claims.

Claims

1. The preparation method of the high-strength SCR catalyst for CO-removal is characterized by comprising the following steps of:

s1, pretreatment of raw materials: alkalizing the carrier component titanium tungsten powder of the SCR denitration catalyst, stirring and mixing uniformly, drying, grinding and crushing, and sieving and separating to obtain pretreated titanium tungsten powder serving as a carrier; the alkalizing agent is one or more of ammonia water, monoethanolamine, triethanolamine and pyridine, and is added in a spray form;

s2, pug mixing: during mixing, adding one or more soluble materials including ammonium metavanadate, ammonium heptamolybdate and cerium nitrate in a solution state, adding all insoluble/indissoluble materials including pore-forming agents, structure auxiliary agents, adhesives and lubricants in a state of crushing, dispersing and no agglomeration, and uniformly mixing all materials to finish mixing;

s3, catalyst extrusion: extruding the pug after mixing in an extruder;

s6, end dipping: immersing one end of the cut catalyst in an immersion liquid, wherein the immersion liquid comprises 10% -20% of copper nitrate, 5% -10% of cobalt acetate, 1% -10% of ammonium niobium oxalate and 0% -20% of one or more soluble salts of one or more active components M, and M is cerium, nickel or lanthanum;

2. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: the impregnation depth of the catalyst in S6 is 10% -25% of the length of the whole catalyst.

3. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: and S6, soaking the catalyst for 20-30 minutes, wherein the temperature of a soaking solution is 45-55 ℃, taking out the catalyst after soaking, standing on a drain net vertically for airing, taking out the catalyst after 20-40 minutes, and performing secondary drying and calcination.

4. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: s6, after the impregnation of one batch of catalyst is finished, manually stirring the impregnating solution uniformly or continuously stirring the impregnating solution by using a circulating pump; and (3) after 5-10 batches of catalysts are impregnated, supplementing the impregnating solution and compensating the concentration, or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump.

5. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: the pore-forming agent is one or more of pulp, carbon powder, terylene, chinlon or polypropylene chopped fibers; the structure auxiliary agent is one or more of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder; the adhesive is one or more of hydroxypropyl methyl cellulose ether, carboxymethyl hydroxyethyl cellulose or phenyl cellulose; the lubricant is one or more of graphite powder, stearic acid, polyimide or poly-p-hydroxybenzoate.

6. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: and S2, when the water content of the mixed materials is 32-35%, mixing is completed.

7. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: the extrusion pressure in the S3 is 1.5Mpa-1.8Mpa, and the extrusion temperature is 30 ℃ to 35 ℃.

8. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: and S4, drying at 30-80 ℃ for 10 hours, calcining at 180-250 ℃ for 6 hours, and calcining at 300-400 ℃ for 4 hours.

9. The method for preparing the CO-removal high-strength SCR catalyst according to claim 1, wherein the method comprises the following steps: s7 is dried at 80 ℃ for 4 hours, calcined at 120-300 ℃ for 6 hours and calcined at 400-650 ℃ for 6 hours.