阅读说明：本技术 一种新型高效脱硝催化剂及其制备方法和应用 (Novel efficient denitration catalyst and preparation method and application thereof ) 是由 肖永厚 邱爽 吴浩然 付佳辉 于 2020-12-10 设计创作，主要内容包括：本发明公开一种新型高效脱硝催化剂及其制备方法和应用。本发明所述的新型高效脱硝催化剂,包括以下重量百分比的组分：二氧化硅3wt％-40wt％；氧化铝25wt％-33wt％；五氧化二磷32wt％-55wt％；铜氨络合物5wt％-10wt％；氟化铵0.01wt％-0.1wt％；本发明通过引入氟离子对一步法合成的Cu-SAPO-34分子筛催化剂进行改性,该方法能够促进分子筛的成核及晶化,并同时具有高结晶度,均匀的颗粒分布,大的比表面积和孔体积,及适宜的酸性。整个制备过程安全、环境友好且节约能耗。本发明的分子筛催化剂在高空速下仍能保持良好的低温活性以及较宽的活性温度窗口,适用于机动车后处理系统催化器中NOx净化过程。(The invention discloses a novel efficient denitration catalyst, and a preparation method and application thereof. The novel efficient denitration catalyst comprises the following components in percentage by weight: 3-40 wt% of silicon dioxide; 25 wt% -33 wt% of alumina; 32-55 wt% of phosphorus pentoxide; 5-10 wt% of copper ammonia complex; 0.01-0.1 wt% of ammonium fluoride; the invention modifies the Cu-SAPO-34 molecular sieve catalyst synthesized by one-step method by introducing fluorinion, and the method can promote the nucleation and crystallization of the molecular sieve, and simultaneously has high crystallinity, uniform particle distribution, large specific surface area and pore volume and proper acidity. The whole preparation process is safe, environment-friendly and energy-saving. The molecular sieve catalyst of the invention can still keep good low-temperature activity and a wider active temperature window under high airspeed, and is suitable for the NOx purification process in a catalyst of an automobile aftertreatment system.)

1. A novel high-efficiency denitration catalyst is characterized by comprising the following components in percentage by weight:

3-40 wt% of silicon dioxide;

25 wt% -33 wt% of alumina;

32-55 wt% of phosphorus pentoxide;

5-10 wt% of copper ammonia complex;

0.01 wt% -0.1 wt% of ammonium fluoride.

2. The preparation method of the novel high-efficiency denitration catalyst of claim 1, characterized by comprising the following steps:

firstly, mixing 20 wt% of copper sulfate solution with tetraethylenepentamine to form a copper ammonia complex, mixing 32 wt% -55 wt% of orthophosphoric acid with 10 wt% -200 wt% of deionized water, adding 5 wt% -10 wt% of the copper ammonia complex, and stirring; then adding 25 to 33 weight percent of pseudo-boehmite and/or aluminum isopropoxide, 3 to 40 weight percent of silica sol and/or ethyl orthosilicate, 25 to 40 weight percent of template agent and 0.01 to 0.1 weight percent of ammonium fluoride in sequence, and continuously stirring for 2 to 10 hours at room temperature;

step two, putting the mixed solution prepared in the step one into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging, transferring into a drying oven, heating to 150-280 ℃, crystallizing for 24-84 h, and cooling to room temperature; filtering and washing for many times until the catalyst is neutral, drying, calcining at high temperature, tabletting, forming and grinding to obtain the novel efficient denitration catalyst.

3. The preparation method of the novel efficient denitration catalyst according to claim 2, wherein the copper ammonia complex comprises tetraethylenepentamine, copper sulfate pentahydrate/anhydrous copper sulfate and deionized water, and the molar ratio of the tetraethylenepentamine to the copper sulfate is 0.5-1.5: 0.1-2.

4. The preparation method of the novel high-efficiency denitration catalyst according to claim 2, wherein the template agent is one or more of morpholine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.

5. The preparation method of the novel efficient denitration catalyst according to claim 2, wherein in the second step, the aging temperature is 25-90 ℃ and the aging time is 6-24 h.

6. The preparation method of the novel high-efficiency denitration catalyst according to claim 2, wherein in the second step, the filtration mode comprises suction filtration, centrifugation or standing filtration; the drying temperature is 80-150 ℃, and the drying time is 10-24 h.

7. The preparation method of the novel high-efficiency denitration catalyst according to claim 2, characterized in that in the second step, the high-temperature calcination is carried out in a tube furnace air atmosphere, the temperature is firstly raised to 300-400 ℃, the water in the catalyst is removed within 2-5 h, the temperature raising rate is 2-8 ℃/min, the temperature is continuously raised to 500-700 ℃, the template agent is removed, the temperature raising rate is kept unchanged from 2 ℃/min to 8 ℃/min, the temperature is finally reduced to the room temperature at the rate of 0.5-5 ℃/min, and the pressure of the tabletting molding in the second step is 5-30 MPa; the grinding mesh number is 40-100 meshes.

8. A novel high-efficiency denitration catalyst is characterized in that before use, the novel high-efficiency denitration catalyst is dried in a vacuum oven at 100-200 ℃ for 10-20 h.

9. Use of a novel high efficiency denitration catalyst according to any one of claims 1 to 8 for selective catalytic reduction removal of NOx in an automotive aftertreatment system, characterized in that it simulates an automobileThe contents of the components of the tail gas are as follows, NH₃: 200-1500ppmv, NO: 200 plus 1500ppmv, 1 to 15 volume percent of O₂And N₂Balancing gas; the activity test experimental conditions of the novel denitration catalyst are as follows: the temperature range is 150-^-1Under the conditions of (1) NH₃-application in the field of SCR NOx removal.

Technical Field

The invention relates to a preparation technology of a molecular sieve catalyst and a technology for removing NOx from tail gas of a motor vehicle, in particular to a preparation method of a novel efficient denitration catalyst and application of the novel efficient denitration catalyst in removing NOx from the tail gas by utilizing ammonia selective catalytic reduction reaction in a motor vehicle aftertreatment system.

Background

With the rapid development of science and technology and economy, the quality of life of people is greatly improved, and the quantity of motor vehicles is rapidly increased. The number of automobiles in nearly 50 cities in China is over million, and under the background, air pollution and haze are aggravated in some cities in China. The analysis of the environmental protection department on PM 2.5 sources of 9 cities such as Beijing shows that the exhaust emission of motor vehicles is a main pollution source of urban atmosphere, which causes serious haze problems in the cities. The generated tail gas not only causes serious ecological environment pollution, but also seriously threatens the health of human beings. Particularly in northern cities, once heating is started in winter, the phenomenon of cross contamination of soot and vehicle exhaust gas is easy to occur, and even more complicated environmental problems are caused, so that the control of the emission of NOx in the exhaust gas of vehicles, particularly diesel vehicles, is not slow at present.

The current technologies for removing NOx can be mainly classified into NOx storage reduction technology (NSR), HC-selective catalytic reduction technology (HC-SCR), and ammonia-selective catalytic reduction technology (NH)₃-SCR) three key technologies. Under oxygen-rich conditions, the major pollutant in motor vehicle exhaust is NOx. The NH3-SCR technology refers to the reduction of NOx under oxygen-rich conditions using ammonia as a reductant. With NH₃Continuous research and optimization of SCR technology catalysts, NH₃SCR technology has high NOx removal efficiency and high N efficiency₂Selectivity and better economy. Therefore, the technology has become the most promising technology for removing NOx from mobile sources such as an automobile exhaust system and the like at present.

NH₃SCR technology has been widely used in industry because of its high NOx removal efficiency, high N2 selectivity and good economy. However for NH₃SCR technology, the selection of the catalyst is the core of the whole denitration technology,good catalyst determines NH₃Denitration efficiency in SCR reactions. Of the numerous catalysts used in the NOx removal technology, noble metal catalysts were first developed for use with NH₃-in SCR technology. But due to the noble metal to NH₃Has certain oxidizing power, so that NO and N are easily oxidized and generated at high temperature₂Secondary contaminants such as O, which results in a narrow temperature window for catalyst activity, N₂The selectivity is poor, and meanwhile, the noble metal is expensive and cannot meet the requirement of NH₃Large-scale application of SCR technology. Noble metal catalysts have now been gradually replaced by metal oxidation catalysts and molecular sieve catalysts. Most of the commercially used metal oxide catalysts are vanadium tungsten titanium system catalysts, but the activity temperature window is narrow, the low-temperature catalytic activity is poor, and vanadium has biotoxicity. Therefore, the development of the catalyst which is environment-friendly and has good low-temperature activity is of great significance.

The molecular sieve catalyst is a catalyst which takes a molecular sieve as a carrier and then loads a corresponding active component. Compared with metal oxidation type catalysts, the molecular sieve catalyst has good stability, large specific surface area and excellent N₂Selectivity and more excellent SCR reaction activity, and thus have received much attention. In the field of denitration, the types of commonly used zeolite molecular sieves mainly include a small-pore CHA type molecular sieve, a mesoporous ZSM-5 molecular sieve and a large-pore Beta molecular sieve. Small pore CHA molecular sieve catalysts have received much attention because of their good activity, hydrothermal stability, and large specific surface area. The Cu-SAPO-34 and Cu-SSZ-13 molecular sieves have the advantages of small pore size, moderate acidity, good hydrothermal stability and the like, and are a very promising catalyst for controlling the emission of the post-treatment of the motor vehicle exhaust. The Cu-SAPO-34 has better catalytic activity and hydrothermal stability than Cu-SSZ-13, and the Cu-SAPO-34 molecular sieve catalyst is lower in preparation cost, so that the Cu-SAPO-34 catalyst is expected to become an optimal candidate material for removing NOx by NH 3-SCR.

Chinese patent CN106914273A discloses a preparation method and application of a one-step in-situ synthesis Cu-SAPO-18 molecular sieve catalyst, which improves the activity of the catalyst by regulating and controlling the content of copper as an active component of the molecular sieve and controlling the factors such as the surface acid concentration and the acid strength of a silicon atom in a molecular sieve structure in a coordination environment, and overcomes the defects of high cost, low raw material utilization rate and the like of the traditional one-step synthesis method. Chinese patent CN107744830A discloses a method for preparing a Cu-based molecular sieve SCR catalyst by a one-step method, which can uniformly disperse Cu2+ on an SAPO-34 molecular sieve by an ion exchange method, thereby obtaining a catalyst with high activity and conversion rate, and meeting the requirements of practical application. Chinese patent CN108525701A discloses a copper-cerium based molecular sieve catalyst for removing NOx of a motor vehicle by low-temperature ammonia-selective catalytic reduction, which is a low-temperature molecular sieve catalyst suitable for a motor vehicle NH3-SCR system, which is researched and designed according to the principle of complementary advantages aiming at different temperature characteristics of activity and selectivity of the catalyst after copper and cerium are loaded, but the copper and cerium loading proportion is difficult to accurately control in the preparation process of the catalyst.

In summary, although some preparation methods of catalysts for removing NOx from motor vehicle exhaust gas are reported in the previous patents, the existing prepared catalysts all have the following problems: a. the raw materials required for preparation are expensive, the preparation conditions are harsh, and large-scale industrial production is not facilitated; b. the catalyst has the advantages of narrow active temperature window, low-temperature activity, easy activation and insufficient denitration efficiency.

Disclosure of Invention

The invention aims to provide a preparation method of a novel efficient denitration catalyst aiming at the problems of insufficient low-temperature activity, narrow active temperature window, high preparation cost and the like of the existing denitration catalyst of a motor vehicle aftertreatment system and aiming at improving the defects of the prior art, and the novel efficient denitration catalyst prepared by the method has the advantages of low cost, simple process, excellent hydrothermal stability and capability of keeping excellent NH in a wider temperature window₃-SCR catalytic activity. In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a novel efficient denitration catalyst, which comprises the following components in percentage by weight:

3-40 wt% of silicon dioxide;

25 wt% -33 wt% of alumina;

32-55 wt% of phosphorus pentoxide;

5-10 wt% of copper ammonia complex;

0.01 wt% -0.1 wt% of ammonium fluoride.

In a second aspect, the invention provides a preparation method of a novel efficient denitration catalyst, which comprises the following steps:

firstly, mixing 20 wt% of copper sulfate solution with tetraethylenepentamine to form a copper ammonia complex, mixing 32 wt% -55 wt% of orthophosphoric acid with 10 wt% -200 wt% of deionized water, adding 5 wt% -10 wt% of the copper ammonia complex, and stirring; then adding 25 wt% -33 wt% of pseudo-boehmite and/or aluminum isopropoxide, 3 wt% -40 wt% of silica sol and/or ethyl orthosilicate, 25 wt% -40 wt% of template agent and 0.01 wt% -0.1 wt% of ammonium fluoride in sequence, and continuously stirring for 2h-10h at room temperature.

Step two, putting the mixed solution prepared in the step one into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging, transferring into a drying oven, heating to 150-280 ℃, crystallizing for 24-84 h, and cooling to room temperature; filtering and washing for many times until the catalyst is neutral, drying, calcining at high temperature, tabletting, forming and grinding to obtain the novel efficient denitration catalyst.

Further, the copper ammonia complex comprises tetraethylenepentamine, copper sulfate pentahydrate/anhydrous copper sulfate and deionized water, wherein the molar ratio of the tetraethylenepentamine to the copper sulfate is 0.5-1.5: 0.1-2.

Further, the template agent adopts one or more of morpholine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.

Further, in the second step, the aging temperature is 25-90 ℃, and the aging time is 6-24 h.

Further, in the second step, the filtration mode comprises suction filtration, centrifugation or standing filtration; the drying temperature is 80-150 ℃, and the drying time is 10-24 h.

Further, in the second step, the high-temperature calcination is carried out in the air atmosphere of a tube furnace, firstly, the temperature is raised to 300-400 ℃, the water in the catalyst is removed for 2-5 h, the temperature raising rate is 2-8 ℃/min, the temperature is continuously raised to 500-700 ℃, the temperature is maintained for 3-7 h, the template agent is removed, the temperature raising rate is unchanged, finally, the temperature is lowered to the room temperature at the rate of 0.5-5 ℃/min, and the pressure for tabletting and forming in the second step is 5-30 MPa; the grinding mesh number is 40-100 meshes.

In a third aspect, the invention also provides a novel efficient denitration catalyst, which is prepared by adopting the preparation method of any one of the novel efficient denitration catalysts in the second aspect.

In a fourth aspect, the invention also provides an application of the novel high-efficiency denitration catalyst in the third aspect in selective catalytic reduction removal of NOx in an automotive aftertreatment system.

Firstly, before the novel high-efficiency denitration catalyst is used, the novel high-efficiency denitration catalyst is dried in a vacuum oven at the temperature of between 100 and 200 ℃ for 10 to 20 hours, and the novel high-efficiency denitration catalyst is dried at the temperature of between 150 and 450 ℃, at the standard atmospheric pressure of 1 and at the gas volume space velocity of 5000-^-1Under the conditions of (1), a mixed gas containing 400-1000ppmv NOx was passed through a fixed bed activity evaluation apparatus packed with the novel denitration catalyst, and the concentration of NOx at the outlet of the fixed bed was detected on line using a flue gas analyzer.

The contents of the components simulating the tail gas of the motor vehicle are as follows, NH₃: 200-1500ppmv, NO: 200 plus 1500ppmv, 1 to 15 volume percent of O₂And N₂Balancing qi. The activity test experimental conditions of the novel denitration catalyst are as follows: the temperature range is 150-^-1Under the conditions of (1) NH₃-application in the field of SCR NOx removal.

The invention provides a novel efficient denitration catalyst, a preparation method and application thereof, and compared with the prior art, the novel efficient denitration catalyst has the following advantages:

1) commercial NH currently used most widely₃The SCR catalyst systems are all vanadium-tungsten-titanium composite materials V₂O₅-WO₃/TiO₂On the basis, the optimal temperature window of the catalyst is extremely narrow, and the active component is extremely volatile at an overhigh temperature, so that the catalyst has potential harm to human health and the surrounding environment. In order to solve the above-mentioned problems,the invention discloses a novel efficient denitration catalyst, which has the advantages of large surface area and pore volume, wide active temperature window, low cost, simple process, environmental friendliness and the like, and can be used for removing NOx for evaluation.

2) The existing Cu-SAPO-34 molecular sieve catalyst has a longer preparation period, and the time cost is invisibly increased. In the invention, ammonium fluoride is added in the process of synthesizing initial gel, and the influence of F anions on the physical properties of the catalyst is examined: crystallinity, specific surface area and pore volume, particle size distribution, zeolite acidity, and the like. The F ions can be used as a template to exist in a zeolite cage, and besides the mineralization effect, the catalyst can also shorten the periodic table of the catalyst in the lake specular region, catalyze Si-O-T (T ═ Si, Al) bond fracture, enhance the acidity of the catalyst, further reduce the preparation period of the catalyst and have more excellent catalytic activity.

3) The Cu-SAPO-34 molecular sieve modified and prepared by the method forms SiF in a weakly acidic medium by adding F ions₆ ^2-The catalyst promotes more monosilicon atoms to be introduced into a molecular sieve frame to form more acid sites, enhances the low-temperature activity of the catalyst, enables the catalyst to still maintain higher NOx conversion rate in a wider temperature window (150 ℃ -400 ℃) and at lower temperature, and simultaneously can still maintain excellent catalytic activity at higher space velocity.

In conclusion, the F-Cu-SAPO-34 molecular sieve catalyst is obtained by adopting one-step hydrothermal synthesis, and F with different concentrations is added into the initial gel of the catalyst, so that the catalyst with better crystal form and larger surface area and pore volume is synthesized, and is environment-friendly, and has high activity, long service life and high stability. The novel denitration catalyst is convenient to operate in a motor vehicle tail gas treatment device, and has certain toxicity resistance and higher NOx conversion rate.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is an XRD pattern of the novel high efficiency denitration catalyst of example 1 and unmodified Cu-SAPO-34.

Fig. 2 is a graph showing the SCR activity of the novel high-efficiency denitration catalysts of examples 1 to 4 after calcination.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

The embodiment of the invention provides a novel efficient denitration catalyst which comprises the following components in percentage by weight: 3-40 wt% of silicon dioxide; 25 wt% -33 wt% of alumina; 32-55 wt% of phosphorus pentoxide; 5-10 wt% of copper ammonia complex; 0.01 wt% -0.1 wt% of ammonium fluoride.

The embodiment of the invention also provides a preparation method of the novel efficient denitration catalyst, which comprises the following steps:

firstly, mixing 20 wt% of copper sulfate solution with tetraethylenepentamine to form a copper ammonia complex, mixing 32 wt% -55 wt% of orthophosphoric acid with 10 wt% -200 wt% of deionized water, adding 5 wt% -10 wt% of the copper ammonia complex, and stirring; then adding 25 wt% -33 wt% of pseudo-boehmite and/or aluminum isopropoxide, 3 wt% -40 wt% of silica sol and/or ethyl orthosilicate, 25 wt% -40 wt% of template agent and 0.01 wt% -0.1 wt% of ammonium fluoride in sequence, and continuously stirring for 2h-10h at room temperature.

Step two, putting the mixed solution prepared in the step one into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging, transferring into a drying oven, heating to 150-280 ℃, crystallizing for 24-84 h, and cooling to room temperature; filtering and washing for many times until the catalyst is neutral, drying, calcining at high temperature, tabletting, forming and grinding to obtain the novel efficient denitration catalyst.

Specifically, the copper ammonia complex comprises tetraethylenepentamine, copper sulfate pentahydrate/anhydrous copper sulfate and deionized water, wherein the molar ratio of the tetraethylenepentamine to the copper sulfate is 0.5-1.5: 0.1-2. The template agent is one or more of morpholine, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.

Specifically, in the second step, the aging temperature is 25-90 ℃, and the aging time is 6-24 h. In the second step, the filtration mode comprises suction filtration, centrifugation or standing filtration; the drying temperature is 80-150 ℃, and the drying time is 10-24 h. In the second step, the high-temperature calcination is carried out in the air atmosphere of a tubular furnace, the temperature is firstly raised to 300-400 ℃, the water in the catalyst is removed for 2-5 h, the heating rate is 2-8 ℃/min, the temperature is continuously raised to 500-700 ℃, the temperature is kept for 3-7 h, the template agent is removed, the heating rate is unchanged, the temperature is finally lowered to the room temperature at the rate of 0.5-5 ℃/min, and the pressure for tabletting and forming in the second step is 5-30 MPa; the grinding mesh number is 40-100 meshes.

The embodiment of the invention also provides a novel efficient denitration catalyst, which is prepared by adopting the preparation method of the novel efficient denitration catalyst. The embodiment of the invention also provides application of the novel efficient denitration catalyst in selective catalytic reduction removal of NOx in an automobile aftertreatment system. Firstly, the novel high-efficiency denitration catalyst is dried in a vacuum oven at the temperature of 100-200 ℃ for 10-20 h before use. The invention is further illustrated below with reference to several specific examples:

example 1

The embodiment discloses a novel high-efficiency denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: first, a 20 wt% copper sulfate solution was prepared, and copper sulfate and tetraethylenepentamine were mixed in a molar ratio of 1: 1, uniformly mixing, and stirring for 2 hours to form a copper ammonia complex for later use; uniformly mixing 12.3g of orthophosphoric acid and 60g of deionized water, adding the copper ammonia complex into the mixture, uniformly mixing, and sequentially adding 14.7g of pseudo-boehmite and 2g of silica sol, 17.4g of morpholine, 0.01% by weight of NH₄And F, stirring for 3-6 hours at room temperature, filling the mixed solution into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging for 12 hours at room temperature, transferring into an oven, heating to 180 ℃, crystallizing for 36 hours, cooling to room temperature, washing, and calcining at high temperature to obtain the novel efficient motor vehicle denitration catalyst.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the embodiment is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 5 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the conditions of (1), the NOx concentration at the outlet of the fixed bed was detected using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency automotive denitration catalyst are given in fig. 1.

Example 2

The embodiment discloses a novel high-efficiency denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: first, a 20 wt% copper sulfate solution was prepared, and copper sulfate and tetraethylenepentamine were mixed in a molar ratio of 1: 1, uniformly mixing, and stirring for 2 hours to form a copper ammonia complex for later use; uniformly mixing 12.3g of orthophosphoric acid and 60g of deionized water, adding a copper ammonia complex into the mixture, uniformly mixing, and sequentially adding 14.7g of pseudo-boehmite, 2g of silica sol, 17.4g of morpholine and 0.05 wt% of NH₄And F, stirring for 3-6 hours at room temperature, filling the mixed solution into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging for 12 hours at room temperature, transferring into an oven, heating to 180 ℃, crystallizing for 36 hours, cooling to room temperature, washing, and calcining at high temperature to obtain the novel efficient motor vehicle denitration catalyst.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the embodiment is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 5 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the conditions of (1), the NOx concentration at the outlet of the fixed bed was detected using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency automotive denitration catalyst are given in fig. 1.

Example 3

The embodiment discloses a novel high-efficiency denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: first, a 20 wt% copper sulfate solution was prepared, and copper sulfate and tetraethylenepentamine were mixed in a molar ratio of 1: 1, uniformly mixing, and stirring for 2 hours to form a copper ammonia complex for later use; uniformly mixing 12.3g of orthophosphoric acid and 60g of deionized water, adding a copper ammonia complex into the mixture, uniformly mixing, and sequentially adding 14.7g of pseudo-boehmite, 2g of silica sol, 17.4g of morpholine and 0.1 wt% of NH₄And F, stirring for 3-6 hours at room temperature, filling the mixed solution into a stainless steel reaction kettle with a polytetrafluoroethylene lining, aging for 12 hours at room temperature, transferring into an oven, heating to 180 ℃, crystallizing for 36 hours, cooling to room temperature, washing, and calcining at high temperature to obtain the novel efficient motor vehicle denitration catalyst.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the embodiment is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 5 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the conditions of (1), the NOx concentration at the outlet of the fixed bed was detected using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency automotive denitration catalyst are given in fig. 1.

Examples 4 to 18

A novel denitration catalyst was prepared and activity-tested according to the respective procedures and conditions of example 1. Only by changing NH₄The amounts of F added, the types of silicon source and template, and the conditions varied are shown in Table 1. The contents of each component in the simulated tail gas are as follows, 5NH of 00ppmv₃500ppmv NO, 1 to 10 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-^-1Under the conditions of (1), the NOx concentration at the outlet of the fixed bed was detected using a flue gas analyzer. Examples 4-18 the results of NOx conversion tests for the preparation of the novel high efficiency denitration catalyst are given in table 2. Fig. 2 is a graph showing the SCR activity of the novel high-efficiency denitration catalysts of examples 1 to 4 after calcination.

Comparative example 1

A novel high-efficiency denitration catalyst is prepared according to the steps and conditions of example 1, and the catalyst is ground and screened into particles with 40-60 meshes. Degassing at 100 deg.C under vacuum for 12 hr.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the comparative example is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 5 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-^-1Under the condition (2), simulating the motor vehicle exhaust to be adsorbed and purified by a fixed bed filled with a novel denitration catalyst, and detecting the concentration of NOx at the outlet of the fixed bed by using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency denitration catalyst are given in table 1.

Comparative example 2

A novel denitration catalyst was prepared according to the steps and conditions of example 2, and the catalyst was ground to screen particles of 40-60 mesh. Degassing at 100 deg.C under vacuum for 12 hr.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the comparative example is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 1 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-^-1Under the condition of (1), the simulatorThe tail gas of the motor car is adsorbed and purified by a fixed bed filled with a novel denitration catalyst, and the concentration of NOx at the outlet of the fixed bed is detected by a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency denitration catalyst are given in table 2.

Comparative example 3

This comparative example 3 discloses a novel high-efficiency denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: mixing 15.5g of orthophosphoric acid and 60g of deionized water, slowly adding 9.2g of pseudoboehmite under stirring, adding 11.5g of morpholine, and stirring at room temperature for 6 hours to form a mixture 1; 6.3g of tetraethoxysilane and 0.05 wt% of NH₄F, mixing, and stirring for 6 hours at room temperature to form a mixture 2; the mixture 2 is added into the mixture 1, then 7.8g of Cu-TEPA is added, ammonia is added dropwise to adjust the pH environment, and the mixture is stirred for 12 hours at room temperature. And (3) putting the mixture into a reaction kettle, crystallizing at 180 ℃ for 48 hours, and calcining at high temperature to obtain the novel denitration catalyst. Grinding and screening the particles with 40-60 meshes. Degassing at 100 deg.C under vacuum for 12 hr.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the comparative example is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 1 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the condition (2), simulating the motor vehicle exhaust to be adsorbed and purified by a fixed bed filled with a novel denitration catalyst, and detecting the concentration of NOx at the outlet of the fixed bed by using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency denitration catalyst are given in table 2.

Comparative example 4

This comparative example 4 discloses a novel high-efficiency denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: mixing 15.5g of orthophosphoric acid and 60g of deionized water, slowly adding 9.2g of pseudo-boehmite under stirring, adding 19.4g of tetraethylammonium hydroxide, and stirring at room temperature for 6 hours to form a mixture 1; 6.3g of ethyl orthosilicateEster and 0.05 wt% NH₄F, mixing, and stirring for 6 hours at room temperature to form a mixture 2; the mixture 2 is added into the mixture 1, then 7.8g of Cu-TEPA is added, ammonia is added dropwise to adjust the pH environment, and the mixture is stirred for 12 hours at room temperature. And (3) putting the mixture into a reaction kettle, crystallizing at 180 ℃ for 48 hours, and calcining at high temperature to obtain the novel denitration catalyst. Grinding and screening the particles with 40-60 meshes. Degassing at 100 deg.C under vacuum for 12 hr.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the comparative example is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. The simulated tail gas had the following contents of each component, 500ppmv NH₃500ppmv NO, 1 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the condition (2), simulating the motor vehicle exhaust to be adsorbed and purified by a fixed bed filled with a novel denitration catalyst, and detecting the concentration of NOx at the outlet of the fixed bed by using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency denitration catalyst are given in table 2.

Comparative example 5

This comparative example 5 discloses a novel high-efficient denitration catalyst, and a preparation method of the novel denitration catalyst comprises the following steps: mixing 15.5g of orthophosphoric acid and 60g of deionized water, slowly adding 9.2g of pseudo-boehmite under stirring, adding 26.8g of tetrapropylammonium hydroxide, and stirring for 6 hours at room temperature to form a mixture 1; 6.3g of tetraethoxysilane and 0.05 wt% of NH₄F, mixing, and stirring for 6 hours at room temperature to form a mixture 2; the mixture 2 is added into the mixture 1, then 7.8g of Cu-TEPA is added, ammonia is added dropwise to adjust the pH environment, and the mixture is stirred for 12 hours at room temperature. And (3) putting the mixture into a reaction kettle, crystallizing at 180 ℃ for 48 hours, and calcining at high temperature to obtain the novel denitration catalyst. Grinding and screening the particles with 40-60 meshes. Degassing at 100 deg.C under vacuum for 12 hr.

On a fixed bed activity evaluation device, the novel high-efficiency denitration catalyst of the comparative example is used for carrying out a simulation test of removing NOx from the tail gas of a motor vehicle, namely a catalyst activity test. Simulating the composition of the exhaustNH at a content of 500ppmv₃500ppmv NO, 1 vol% O₂And N₂Balancing qi. The activity test temperature range of the catalyst is 150-450 ℃, the standard atmospheric pressure is 1, and the gas volume space velocity is 100000h^-1Under the condition (2), simulating the motor vehicle exhaust to be adsorbed and purified by a fixed bed filled with a novel denitration catalyst, and detecting the concentration of NOx at the outlet of the fixed bed by using a flue gas analyzer. The results of the NOx conversion test for the novel high efficiency denitration catalyst are given in table 2.

TABLE 1 raw material composition of each example and comparative example

TABLE 2 evaluation conditions and results of activity in examples and comparative examples

As can be seen from the comparison results of the embodiment and the comparative example, the technical scheme provided by the invention well solves the problems of narrow active temperature window, poor low-temperature activity, low NOx conversion rate and the like of the catalyst, and obtains better technical effect.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.