CN113996309A

CN113996309A - Preparation method of high-strength SCR catalyst for CO collaborative removal

Info

Publication number: CN113996309A
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: 2022-02-01
Anticipated expiration: 2041-11-23
Also published as: CN113996309B

Abstract

The invention discloses a preparation method of a high-strength SCR (selective catalytic reduction) catalyst with CO synergistic removal, belonging to the field of SCR denitration catalysts. The denitration catalyst capable of synergistically removing CO is obtained by soaking the catalyst in a soaking solution containing one or more of copper nitrate, cobalt acetate, ammonium niobium oxalate and aluminum sulfate and 0-20% of soluble salt of one or more 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 an exothermic reaction, so that the CO can be removed, the flue gas temperature can be increased, and the activity of the rear-end SCR catalyst is improved. The end part of the catalyst is dipped to ensure the denitration efficiency of the catalyst, and the problem of high production cost of the catalyst which is totally dipped and integrally prepared can be avoided.

Description

Preparation method of high-strength SCR catalyst for CO collaborative 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 synergistic removal.

Background

The SCR denitration catalyst is mainly applied to flue gas denitration of boilers which mainly use thermal power and relate to coal burning and gas burning in various industries at present. In this regard, there is inevitably insufficient combustion in all fossil fuel combustion processes, thereby generating a large amount of CO gas. In order to avoid the waste of the partial energy, larger coal-fired and gas-fired boilers such as thermal power plants and steel plants adopt partial flue gas circulation, secondary combustion and other process flows and devices, but the low content of CO in the discharged flue gas cannot be ensured, especially the load of the boiler is reduced during the peak shaving operation of the thermal power plants, the furnace temperature is lower, and the full combustion is more difficult to ensure; for smaller boilers, which often do not have the above-described process and apparatus, the flue gas has a higher CO content.

CO has strong toxicity, can harm human internal organs and brain tissues at higher concentration, can form explosive mixture when being mixed with air at certain concentration, and can be finally converted into CO through the reaction with hydroxyl compounds in the atmosphere₂。

The related research shows that the CO content in the flue gas of the thermal power plant including the supercritical opposed firing boiler and the biomass solid firing boiler is 500-2500 mg/m³. At the same time with the continuous tightening of the national policy for environmental protection, andthe national strict control on the carbon emission is that the removal of CO in the flue gas is absolutely the same as the removal of NO.

Chinese patent CN 112316943A discloses a method for preparing a coconut shell activated carbon₂Low-temperature CO-SCR denitration Cu with O as active component₂The O/AC catalyst, however, the catalyst prepared by the activated carbon in the patent has weak selectivity and poor stability, and is not convenient for long-term industrial application. The Chinese patent CN 111229212A takes manganese as an active component, and adds copper, iron, cerium, cobalt or nickel to the manganese active component to improve the poisoning effect of water vapor on a catalyst and improve the competition of oxygen and nitrogen oxides on carbon monoxide, so that the carbon monoxide and the nitrogen oxides preferentially generate catalytic reduction reaction. However, the catalyst prepared by the patent is completely an active component oxide, has no catalyst carrier, and has high cost, relatively small reaction contact area and certain difficulty in industrial application. Chinese patent CN 113441131A adopts a modified V-Mo-Ti system catalyst as a carrier, and is added with a plurality of catalytic factors. However, this patent describes a co-denitration catalyst of the monolithic extrusion 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 is characterized in that titanium tungsten powder is used as a carrier, one or more of vanadium, cobalt, cerium and lanthanum are used as main active components, one or more of copper, tungsten, molybdenum and niobium are used as auxiliary active components, and 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 CO synergistic removal high-strength SCR catalyst, which comprises the following steps:

s1, raw material pretreatment: carrying out alkalization treatment on titanium tungsten powder serving as a carrier component of the SCR denitration catalyst, stirring and mixing uniformly, drying, grinding, crushing, 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/insoluble materials including a pore-forming agent, a structural assistant, an adhesive and a lubricant in a crushed, dispersed and agglomeration-free state, uniformly mixing all the materials, and finishing mixing;

s3, extruding the catalyst: 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 design size, and cutting into strip-shaped catalysts with uniform size;

s6, end dipping: dipping one end of the cut catalyst in a dipping solution, wherein the dipping solution contains 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 soluble salt of one or more active components M, and M is cerium, nickel or lanthanum;

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

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

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

Partial impregnation is adopted, elements such as nickel, cobalt, lanthanum, niobium and the like are loaded on the surface of the end of the catalyst, and the elements can play a synergistic effect with elements such as cerium, molybdenum and vanadium in the catalyst, so that 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 impregnation time of the catalyst in S6 is 20-30 minutes, the temperature of the impregnation liquid is 45-55 ℃, the catalyst is taken out after the impregnation is finished and vertically placed on a drain net for airing, and the catalyst is taken out after 20-40 minutes and then is subjected to secondary drying and calcination.

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

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

Preferably, the pore-forming agent is one or more of paper pulp, carbon powder, polyester fiber or nylon chopped fiber; one or more of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder as the structural auxiliary agent; 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 the S2 is 32-35%. The high water content is mainly used for improving the porosity of the catalyst and slowing down the dehydration and drying process of the catalyst.

Preferably, the extrusion pressure in S3 is 1.5MPa-1.8MPa, and the extrusion temperature is 30-35 ℃. The extrusion pressure is low, mainly aiming at reducing the pug temperature and temperature difference, reducing the expansion rate after extrusion, reducing the damage rate of the microstructure and improving the porosity of the catalyst. The extrusion temperature is low, mainly in order to reduce the temperature difference between the extruded catalyst and the environment, avoid strong water loss and reduce the temperature difference caused by uneven heat transfer in the drying process, and the corresponding water loss difference, and avoid collapse damage and macrocracks of the micro-pore structure 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, and the overall calcination time is also shorter, so that the condition of excessive calcination in the secondary calcination is mainly avoided, and meanwhile, the primary calcination time is properly reduced and the calcination temperature is properly reduced 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 titanium-tungsten powder subjected to alkalization treatment as a carrier and one or more of vanadium oxide, cerium oxide, molybdenum oxide and niobium oxide as active components, mixes pug, then performs extrusion molding and primary drying and calcination to obtain a primary blank, and then performs cutting, impregnation hardening load treatment and secondary drying and calcination to obtain the titanium-tungsten composite material. The denitration catalyst capable of synergistically removing CO is obtained by soaking the catalyst in a soaking solution containing one or more of copper nitrate, cobalt acetate, ammonium niobium oxalate and aluminum sulfate and 0-20% of soluble salt of one or more 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 and selectively catalyzes and removes CO to generate an exothermic reaction, so that the CO can be removed, the flue gas temperature can be increased, and the activity of a rear-end SCR catalyst is further improved. The catalyst is impregnated on the surface of the catalyst to load the components with the synergistic catalytic effect, so that the catalytic removal performance of the catalyst on CO and NOx is further improved. The end part of the catalyst is dipped to ensure the denitration efficiency of the catalyst, and the problem of high production cost of the catalyst which is totally dipped and integrally prepared can be avoided.

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

(3) According to the catalyst prepared by the method, the CO component with lower concentration in the flue gas can be removed at the front end of the SCR catalyst, a new device does not need to be added, and the denitration efficiency of the SCR catalyst is not reduced.

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

Detailed Description

In order to make the technical means, innovative features, objectives and functions realized by the present invention easy to understand, the present invention is further described below.

The examples described herein are specific embodiments of the present invention, are intended to be illustrative and exemplary in nature, and are not to be construed as limiting the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification of the present application, and these technical solutions include technical solutions which make any obvious replacement or modification for the embodiments described herein.

When the SCR denitration catalyst is prepared, 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 removing the high-strength SCR catalyst by CO in a synergic manner, which comprises the following steps:

1. s1, raw material pretreatment: carrying out alkalization treatment on titanium tungsten powder serving as a carrier component 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 alkalization agent is one or more of ammonia water, monoethanolamine, triethanolamine and pyridine, and is added in a spray form. Preferably, ammonia water is used for alkalization treatment, the concentration of the ammonia water is 30%, the adding proportion of the ammonia water is 1L/100kg, the ammonia water is added in a spraying mode, 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, passes through a 8000-mesh screen and is screened and sieved with 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/indissolvable materials including a pore-forming agent, a structural assistant, an adhesive and a lubricant are added in a state of crushing, dispersing and no agglomeration, all the materials are uniformly mixed, and mixing is completed. And finishing mixing when the water content of the mixed materials is 32-35%. The pore-forming agent is one or more of paper pulp, carbon powder, polyester fiber or nylon chopped fiber; one or more of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder as the structural auxiliary agent; 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, extruding the catalyst: 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 ℃ for 10 hours, calcining at 180-250 ℃ for 6 hours, and calcining at 300-400 ℃ for 4 hours.

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

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

S7, secondary drying and calcining: and drying and calcining the impregnated catalyst for the second time after drying. 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 present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.

Example 1

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

Adding 5.31kg of sieved titanium tungsten powder into a mixing roll, then adding 0.24kg of ammonium metavanadate, 0.41kg of ammonium heptamolybdate and 0.36kg of cerium nitrate into the mixing roll in a solution state, preliminarily mixing uniformly, then sequentially adding 125g of crushed paper pulp, 3.12kg of silicon-aluminum ionic binder, 250g of carboxymethyl hydroxyethyl cellulose and 312g of poly-p-hydroxybenzoate into the mixing roll, uniformly mixing, and finishing mixing when the water content of the mixed materials is 32-35%.

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 in the gradual temperature rise drying at the temperature of 30-80 ℃, and then calcining for 6 hours at the temperature of 180-250 ℃, wherein the calcining time is 4 hours at the maximum temperature of 400 ℃.

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

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 boxing and packaging.

Example 2

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

10kg of sieved titanium-tungsten powder is taken and added into a mixing roll, then 0.46kg of ammonium metavanadate, 0.78kg of ammonium heptamolybdate and 0.68kg of cerium nitrate are added into the mixing roll in a solution state and are primarily mixed uniformly, 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 roll and are uniformly mixed, and when the water content of the materials is 32-35% after mixing, the mixing is finished.

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

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

And removing the damaged and cracked part according to the designed size, and cutting into strip-shaped catalysts 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, 20% aluminum sulfate. The depth of impregnation was 15% of the length of the whole catalyst. The dipping time is 30min, the temperature of the dipping liquid is 50 ℃, the catalyst is taken out after the dipping is finished and is vertically erected on a drain net for airing, and the catalyst is taken down after 30min for secondary drying and calcining. When the impregnation of a batch of catalyst is finished, uniformly stirring the impregnation liquid by manual stirring or continuously stirring the impregnation liquid by using a circulating pump; and (3) supplementing and compensating the concentration of the impregnating solution or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump every time 5-10 batches of catalysts are impregnated.

Drying at 80 deg.C for 4 hr, calcining at 120-300 deg.C for 6 hr, and calcining at 500 deg.C for 6 hr. And screening the catalyst subjected to secondary calcination, removing the damaged catalyst, and boxing and packaging.

Example 3

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

Adding 8.6kg of the sieved titanium-tungsten powder carrier into a mixing roll, then adding 0.39kg of ammonium metavanadate and 0.68kg of ammonium heptamolybdate into the mixing roll in a solution state, preliminarily mixing uniformly, and 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 roll, fully mixing uniformly, and finishing mixing when the water content of the materials is 32-35% after mixing.

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. Gradually heating and drying for 10 hours at the temperature of 30-80 ℃, then heating and calcining for 6 hours at the temperature of 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 strip-shaped catalysts with uniform size. One end of the cut catalyst was immersed in an immersion liquid containing 5% of copper nitrate, 5% of nickel nitrate, 2% of lanthanum nitrate, 3% of ammonium niobium oxalate, and 25% of aluminum sulfate. The depth of impregnation was 20% of the length of the whole catalyst. The dipping time is 30min, the temperature of the dipping liquid is 50 ℃, the catalyst is taken out after the dipping is finished and is vertically erected on a drain net for airing, and the catalyst is taken down after 30min for secondary drying and calcining. When the impregnation of a batch of catalyst is finished, uniformly stirring the impregnation liquid by manual stirring or continuously stirring the impregnation liquid by using a circulating pump; and (3) supplementing and compensating the concentration of the impregnating solution or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump every time 5-10 batches of catalysts are impregnated.

Drying at 80 deg.C for 4 hr, calcining 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 boxing and packaging.

Comparative example 1

The comparative example, which is different from example 1 in that the cut catalyst is directly calcined twice without impregnation, is identical to example 1 except that the sample of preparation example 1 is used as a control group and the experimental group is set.

Test examples

The finished catalysts prepared in the above examples and comparative examples were subjected to detection evaluation. Catalyst attrition samples were prepared and subjected to attrition performance evaluation in accordance with 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 activity test samples having the same size of about 3X 3cm end face and 30cm length, and the activity test samples were placed in a reactor. 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^-1The content of mixed gas is as follows: NOx 180ppm, CO 100ppm, O₂ 5％，H₂O10% and nitrogen as carrier gas. Mixing the gases through a mass flow meter, then feeding the mixed gases into a reactor, wherein the reactor is a quartz tube with the inner diameter of 6cm, and placing the reactor in a three-section heating vertical tube furnace for heating; and collecting the exhaust gas by a portable smoke analyzer of Deutsche TD-350 at a sampling port for analysis. The evaluation conditions of the samples for CO and NOx performance are shown in Table 1, and the test results are shown in Table 3.

Catalyst pair NO_xConversion ratio of (2):

conversion of catalyst to CO:

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

Item	Applications 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 O₂Content/%	5	5	5
Space velocity/h^-1	4000	4000	4000
				Molar ratio of ammonia to nitrogen	1:1	1:1	1:1
Temperature/. degree.C	200	240	280
				Reaction time/h	2	2	2

TABLE 2 evaluation of the abrasion Performance of each catalyst product of examples

TABLE 3 abrasion Performance test of catalyst products of preparation examples

Tables 2 and 3 show that the catalyst prepared by the method of the invention has the removal efficiency of CO and NOx of more than 60% and 80% respectively under various application conditions, and the removal effect is stable, wherein the sample prepared in example 1 has the best performance. Compared with a comparative sample, the wear resistance and the catalytic removal performance of CO and NOx of the catalyst sample prepared in the embodiment are obviously improved; compared with the comparative sample, the abrasion performance of the sample in the example 1 is improved by about 40%, and the catalytic performance to CO and NOx is improved by 43.4% and 9.5%, because after the impregnation is carried out by adopting the M solution, aluminum sulfate and niobium oxalate in the impregnation solution form a wear-resistant gel layer on the surface of the catalyst, and a wear-resistant layer is formed after the drying and the calcination, so that the wear-resistant performance of the catalyst is improved. The surface of the catalyst is impregnated and loaded with elements such as cobalt, nickel, lanthanum, niobium and the like, and the elements and the original elements such as cerium, vanadium and molybdenum of the catalyst form a synergistic removal effect, so that the removal efficiency of the catalyst on CO and NOx is greatly improved.

The above embodiments are merely illustrative, and not restrictive, of the scope of the claims, and other alternatives that may occur to those skilled in the art from consideration of the specification should be construed as being within the scope of the claims.

Claims

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

s2, pug mixing: adding one or more soluble materials of ammonium metavanadate, ammonium heptamolybdate and cerium nitrate in a solution state during mixing, adding all insoluble/indissolvable materials including a pore-forming agent, a structural assistant, an adhesive and a lubricant in a state of crushing, dispersing and no agglomeration, uniformly mixing all the materials, and finishing mixing;

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

s6, end dipping: dipping one end of the cut catalyst in a dipping solution, wherein the dipping solution contains one or more of 10-20% of copper nitrate, 5-10% of cobalt acetate, 1-10% of ammonium niobium oxalate, 20-25% of aluminum sulfate and 0-20% of soluble salt of one or more active components M, and M is cerium, nickel or lanthanum;

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

3. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: and the impregnation time of the catalyst in the S6 is 20-30 minutes, the temperature of the impregnation liquid is 45-55 ℃, the catalyst is taken out after the impregnation is finished and vertically erected on a drain net for air drying, and the catalyst is taken out after 20-40 minutes for secondary drying and calcining.

4. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: in S6, when the impregnation of a batch of catalyst is finished, uniformly stirring the impregnation liquid by manual stirring or continuously stirring the impregnation liquid by a circulating pump; and (3) supplementing and compensating the concentration of the impregnating solution or continuously supplementing the impregnating solution and adjusting the concentration by using a circulating pump every time 5-10 batches of catalysts are impregnated.

5. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: the alkalifying agent in S1 is one or more of ammonia water, monoethanolamine, triethanolamine and pyridine, and is added in spray form.

6. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: the pore-forming agent is one or more of paper pulp, carbon powder, terylene, chinlon or polypropylene chopped fiber; one or more of silicon-aluminum ion binder, glass fiber or aluminum silicate fiber powder as the structural auxiliary agent; 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.

7. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: and (3) when the water content of the mixed materials in the S2 is 32-35%, finishing mixing.

8. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: the extrusion pressure in S3 is 1.5Mpa-1.8Mpa, and the extrusion temperature is 30 ℃ to 35 ℃.

9. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: drying at 30-80 ℃ for 10 hours in S4, calcining at 180-250 ℃ for 6 hours, and calcining at 300-400 ℃ for 4 hours.

10. The preparation method of the CO-synergetic removal high-strength SCR catalyst according to claim 1, wherein: s7 is dried at 80 ℃ for 4 hours, calcined at 120-300 ℃ for 6 hours, and calcined at 400-650 ℃ for 6 hours.