阅读说明：本技术 一种拓宽scr催化剂反应温度窗口的催化剂及改性方法 (Catalyst for widening reaction temperature window of SCR (Selective catalytic reduction) catalyst and modification method ) 是由 徐晓涛 潘栋 刘国友 高太振 王长海 朱磊 唱文学 王芳 于 2021-10-27 设计创作，主要内容包括：本发明提供一种拓宽SCR催化剂反应温度窗口的催化剂及改性方法,所述方法包括以下步骤,步骤a,将SCR催化剂单体放在体积浓度1-2mol/L的NH-(4)VO-(3)溶液中进行浸渍；步骤b,将浸渍后的SCR催化剂单体在室温下自然风干；步骤c,将风干后的SCR催化剂单体进行煅烧,制得改性催化剂。本发明通过将SCR催化剂单体采用在NH-(4)VO-(3)溶液中进行浸渍、在室温下自然风干、在一定条件下进行煅烧的方式制备得到改性催化剂,有效提高了SCR催化剂单体在低温区域脱硝的活性和效率,并且在高温区域不失活,具有超宽温窗,对温度的适应性更好；同时本发明方法简单,容易操作,环保经济,具有较高的工业化应用水平。(The invention provides a catalyst for widening the reaction temperature window of an SCR (selective catalytic reduction) catalyst and a modification method thereof, wherein the method comprises the following step of (a) putting an SCR catalyst monomer in NH with the volume concentration of 1-2mol/L 4 VO 3 Dipping in the solution; step b, naturally drying the impregnated SCR catalyst monomer at room temperature; and c, calcining the air-dried SCR catalyst monomer to prepare the modified catalyst. The invention adopts SCR catalyst monomerAt NH 4 VO 3 The modified catalyst is prepared by soaking in the solution, naturally drying at room temperature and calcining under certain conditions, so that the activity and efficiency of the SCR catalyst monomer in denitration in a low-temperature area are effectively improved, the SCR catalyst monomer is not inactivated in a high-temperature area, and the SCR catalyst has an ultra-wide temperature window and is better in temperature adaptability; meanwhile, the method is simple, easy to operate, environment-friendly and economical, and has a high industrial application level.)

1. A catalyst modification method for widening the reaction temperature window of an SCR catalyst is characterized by comprising the following steps,

step a, putting an SCR catalyst monomer in NH with the volume concentration of 1-2mol/L₄VO₃Dipping in the solution;

step b, naturally drying the impregnated SCR catalyst monomer at room temperature;

and c, calcining the air-dried SCR catalyst monomer to prepare the modified catalyst.

2. The method for modifying a catalyst to widen the reaction temperature window of SCR catalyst as claimed in claim 1, wherein in step c, the calcination process is,

i), heating from room temperature to 110-130 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 110-130 ℃ for at least 24 h;

II), heating from 110-130 ℃ to 550-600 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for at least 96h at 550-600 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

3. The method for modifying a catalyst to widen the reaction temperature window of SCR catalyst as claimed in claim 1, wherein in step c, the calcination process is,

i), heating from room temperature to 110 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 110 ℃ for 24 h;

II), heating from 110 ℃ to 550 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for 96h at 550 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

4. The method for modifying a catalyst to widen the reaction temperature window of an SCR catalyst as claimed in claim 1, wherein in step a, the NH is 1-2mol/L₄VO₃The preparation steps of the solution are as follows,

reacting NH₄VO₃Adding the mixture into desalted water, fully stirring, and then adding the ethanolamine solution into the desalted water under the constant temperature and stirring until the volume concentration reaches 1-2 mol/L.

5. The method for modifying the catalyst for widening the reaction temperature window of the SCR catalyst according to claim 4, wherein the constant temperature is 70-90 ℃.

6. The method for modifying the catalyst for widening the reaction temperature window of the SCR catalyst as recited in claim 4, wherein the ethanolamine solution is added in a total amount of 200 to 300ml, and 30 to 50ml of the ethanolamine solution is added to a beaker each time until NH is formed₄VO₃After complete dissolution, the volume concentration reaches 1-2 mol/L.

7. The method as claimed in claim 1, wherein in step a, the SCR catalyst monomer is at 1-2mol/L NH₄VO₃The immersion time in the solution was 3 h.

8. A catalyst for broadening the reaction temperature window of an SCR catalyst, obtainable by a process according to any one of claims 1 to 7.

Technical Field

The invention relates to the technical field of modification of SCR denitration catalysts in the thermal power industry, in particular to a catalyst for widening a reaction temperature window of an SCR catalyst and a modification method.

Background

Selective Catalytic Reduction (SCR) is the mainstream technology in the denitration process of the coal-fired power plant in China, a catalyst is the core component of an SCR denitration system, the performance of the catalyst has direct influence on the denitration effect, and the flue gas temperature has a decisive role in the reaction speed, the reaction activity and the service life of the catalyst and is one of important factors influencing the SCR denitration efficiency. The reaction temperature of the denitration catalyst of the SCR catalyst commonly used in domestic coal-fired power plants is generally 300-420 ℃, the designed reaction temperature of the catalyst is different according to different projects, the denitration catalyst operates at the designed temperature, the activity of the catalyst is optimal, and the denitration efficiency is optimal. The SCR reaction efficiency is improved along with the rise of the temperature, the corresponding ammonia escape rate is gradually reduced, when the temperature of the flue gas is lower than the lower limit of the applicable temperature range of the catalyst, side reaction can occur on the catalyst, the denitration efficiency is reduced, side reaction products are attached to the surface of the catalyst, and micropores of a catalyst channel are blocked to enter one partAbrasion of the catalyst is caused; when the temperature of the flue gas is higher than the adaptive temperature of the catalyst, the micropores of the catalyst channel are deformed, so that the activity of the catalyst is reduced, and the service life of the catalyst is shortened. The most widely used commercial SCR catalyst is currently a metal oxide catalyst, the major component of which is V₂O₅-WO₃/TiO₂The existing method for widening the reaction temperature window is generally to change the active components of the catalyst, and usually to add a metal oxide with better activity at low temperature, and the manufacturing process of the catalyst under the modification method is greatly changed, is more complex and has low efficiency.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a catalyst for widening the reaction temperature window of an SCR catalyst and a modification method thereof, which have the advantages of reasonable design and simple operation and can effectively widen the reaction temperature window of the SCR catalyst.

The invention is realized by the following technical scheme:

a catalyst modification method for widening the reaction temperature window of an SCR catalyst comprises the following steps,

step a, putting an SCR catalyst monomer in NH with the volume concentration of 1-2mol/L₄VO₃Dipping in the solution;

step b, naturally drying the impregnated SCR catalyst monomer at room temperature;

and c, calcining the air-dried SCR catalyst monomer to prepare the modified catalyst.

Optionally, in step c, the calcination process is,

i), heating from room temperature to 110-130 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 110-130 ℃ for at least 24 h;

II), heating from 110-130 ℃ to 550-600 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for at least 96h at 550-600 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

Optionally, in step c, the calcination process is,

i), heating from room temperature to 110 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 110 ℃ for 24 h;

II), heating from 110 ℃ to 550 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for 96h at 550 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

Optionally, in step a, 1-2mol/L of NH₄VO₃The preparation steps of the solution are as follows,

reacting NH₄VO₃Adding the mixture into desalted water, fully stirring, and then adding the ethanolamine solution into the desalted water under the constant temperature and stirring until the volume concentration reaches 1-2 mol/L.

Optionally, the constant temperature is 70-90 ℃.

Optionally, the total amount of the ethanolamine solution is 200-300 ml, and 30-50 ml of ethanolamine solution is added into the beaker every time until NH is formed₄VO₃After complete dissolution, the volume concentration reaches 1-2 mol/L.

Optionally, in step a, the SCR catalyst monomer is at 1-2mol/L of NH₄VO₃The immersion time in the solution was 3 h.

A catalyst for widening the reaction temperature window of an SCR catalyst is prepared by any one of the methods.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention adopts the SCR catalyst monomer in NH₄VO₃The modified catalyst is prepared by soaking in the solution, naturally drying at room temperature and calcining under certain conditions, so that the activity and efficiency of the SCR catalyst monomer in denitration in a low-temperature area are effectively improved, the SCR catalyst monomer is not inactivated in a high-temperature area, and the SCR catalyst has an ultra-wide temperature window and is better in temperature adaptability; meanwhile, the method is simple, easy to operate, environment-friendly and economical, and has a high industrial application level.

Furthermore, the impregnated and air-dried SCR catalyst monomer is subjected to a long-time calcination process, and the temperature during calcination is slightly higher than that of the conventional method, so that the loaded matter on the surface of the impregnated SCR catalyst monomer can be fully decomposed into effective active ingredients, and the activity and efficiency of denitration in a low-temperature area are ensured.

Further, the invention adds NH under the constant temperature heating state₄VO₃Adding ethanolamine solution into the solution to obtain a soaking solution capable of dissolving NH₄VO₃Fully dissolved and prevented from NH₄VO₃And low-temperature precipitation is carried out, so that the concentration of the impregnation liquid is accurate and controllable.

Furthermore, the invention adopts a constant temperature environment of 70-90 ℃ when preparing the steeping liquor, can effectively ensure the dissolving effect and avoid NH generated by over-low temperature₄VO₃The low-temperature precipitation phenomenon occurs.

Furthermore, the invention can effectively ensure NH by adding the ethanolamine solution for several times₄VO₃The dissolution proceeds sufficiently, thereby improving the impregnation effect.

Drawings

Fig. 1 is a schematic structural diagram of the experimental apparatus for simulated denitration in embodiment 1 of the present invention.

In the figure: 1. the system comprises an oxygen supply pipeline, a sulfur dioxide supply pipeline, a nitric oxide supply pipeline, a nitrogen supply pipeline, a ammonia supply pipeline, a mixing tank, a first-stage preheater, a second-stage preheater, a reactor, an inlet sampling pipeline, an outlet sampling pipeline, an emptying pipeline, a ball valve, a rotor flow meter, a mass flow meter and a mass flow meter, wherein the oxygen supply pipeline is 2, the sulfur dioxide supply pipeline is 3, the nitric oxide supply pipeline is 3, the nitrogen supply pipeline is 4, the ammonia supply pipeline is 5, the mixing tank is 6, the first-stage preheater is 7, the second-stage preheater is 8, the reactor is 9, the inlet sampling pipeline is 10, the outlet sampling pipeline is 11, the emptying pipeline is 12, the ball valve is 13, the rotor flow meter is 14, and the mass flow meter is 15.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

Example 1

The invention relates to a catalyst modification method for widening a reaction temperature window of an SCR (selective catalytic reduction) catalyst, which is described in the embodiment by taking a honeycomb SCR catalyst monomer which runs for 24000h as a material, wherein the intercept of the catalyst monomer is 6.88mm, and the pore diameter is 6.22 mm;

firstly, intercepting two small-sized catalytic samples A and B with 6 multiplied by 6 holes from the catalyst monomer to be used as an experimental SCR catalyst monomer; at the same time, 351g (3mol) of NH were weighed out₄VO₃Adding appropriate amount of demineralized water into a beaker, fully stirring, placing the beaker in a constant-temperature water bath, adding ethanolamine solution into the beaker while stirring when the water temperature is raised to 80 ℃, and adding 50ml to NH each time₄VO₃Completely dissolving (adding 250ml of ethanolamine), and finally fixing the volume of the solution to 3L to obtain NH with the volume concentration of 1-2mol/L₄VO₃The solution is used as a steeping fluid;

secondly, putting the sample B into the solution, soaking for about 3 hours, taking out, naturally drying at room temperature, and then putting into a resistance furnace for calcination, wherein the calcination process is as follows:

slowly heating from room temperature to 110 ℃, wherein the heating rate is less than 3 ℃/min;

II, preserving the heat for 24 hours at 110 ℃;

III, heating from 110 ℃ to 550 ℃, wherein the heating rate is less than 3 ℃/min;

IV, calcining for 96 hours at 550 ℃;

and V, naturally cooling to room temperature.

Finally, a modified catalyst sample B was prepared after calcination was complete.

In this embodiment, a simulated denitration experiment is performed on the sample a and the modified catalyst sample B by using a simulated denitration experiment device, and the experimental flue gas is composed of N₂、O₂、NO、SO₂And NH₃Mixing to obtain the final product, wherein O in the simulated flue gas is₂Concentration 3.6%, NO concentration 360ppm, SO₂Concentration of 360-390 ppm, NH₃The mol ratio of NO to the total molecular weight is 1, and the reaction temperature is 300-400 ℃;

as shown in FIG. 1, each gas in the simulated denitration experimental device is a standard steel cylinder gas, O₂Through oxygen supply line 1, SO₂Through a sulfur dioxide supply pipeline 2, NO through a nitric oxide supply pipeline 3, N₂Through nitrogen gas supply line 4, NH₃Fed into the apparatus through an ammonia gas supply line 5, each provided with a ball valve 13, N₂、O₂Is controlled by a rotameter 14, NO, SO₂And NH₃Is controlled by a mass flow meter 15; the primary preheater 7 and the secondary preheater 8 are both electrically heated and are provided with temperature controllers; inverse directionThe reactor 9 is a stainless steel cylindrical structure, the diameter is 60mm, and the length is 500 mm; the reactor 9 is in an electric heating mode, the temperature is controlled by a temperature control meter, an inlet sampling pipeline 10 is arranged at the inlet of the reactor, and an outlet sampling pipeline 11 and an emptying pipeline 12 are arranged at the outlet of the reactor; ball valves 13 are arranged on the inlet sampling pipeline 10 and the outlet sampling pipeline 11.

At the beginning of the simulation experiment, the sample A and the modified catalyst sample B are respectively put into the reactor 9 for simulation experiment, NH₃And N₂Mixed to form NH₃/N₂Directly into reactor 9, NO and N₂First mixed to form NO/N₂Then with O₂And SO₂After being mixed, the mixture is preheated to a certain temperature by a first-stage preheater 7 and a second-stage preheater 8 and then enters a reactor 9; flue gas analyzer using testo350XL for on-line measurement of NO and O in flue gas at inlet sampling pipeline 10 and outlet sampling pipeline 11 respectively₂Concentration;

according to the measurement result of the simulation experiment, the denitration efficiency of the sample A is 46.7 percent and the denitration efficiency of the modified catalyst sample B is 68.5 percent below 300 ℃, and the denitration efficiency of the sample A is obviously lower than that of the modified catalyst sample B; and along with the rise of the temperature, the denitration efficiency of the two samples is gradually increased, the denitration efficiency of the sample A reaches 72.5% of the maximum value at 380 ℃, and the denitration efficiency of the modified catalyst sample B reaches 74.2% of the maximum value at 360 ℃. The test result shows that the denitration performance of the modified catalyst sample B in the low-temperature section is stronger than that of the sample A, the denitration efficiency change range of the modified catalyst sample B in the whole test temperature range is small, the minimum denitration efficiency is 68.5%, the maximum denitration efficiency is 74.2%, and the adaptability of the modified catalyst sample B to the temperature is better, which indicates that the catalyst modification method provided by the invention is beneficial to widening the denitration activity temperature interval of the catalyst.

The invention also provides a catalyst for widening the reaction temperature window of the SCR catalyst, which is prepared by adopting any one of the methods.

Example 2

In this example, NH concentration of 1 to 2mol/L₄VO₃The preparation of the solution is carried out in a constant temperature environment of 70 ℃, and the total adding amount of the ethanolamine solution300 ml; the temperature in the calcining process is 130 ℃ and 600 ℃ respectively;

the specific procedure is as follows,

first, NH is added₄VO₃Adding into desalted water, stirring thoroughly, adding 30ml ethanolamine solution at constant temperature of 70 deg.C until NH₄VO₃After the solution is completely dissolved, the volume concentration reaches 1-2mol/L and then the solution is used as an impregnation solution for standby; putting an SCR catalyst monomer into the impregnation liquid for impregnation;

secondly, naturally drying the impregnated SCR catalyst monomer at room temperature;

finally, calcining the air-dried SCR catalyst monomer, wherein the calcining process comprises the following steps,

i), heating from room temperature to 130 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 130 ℃ for at least 24 h;

II), heating from 130 ℃ to 600 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for at least 96h at 600 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

And obtaining the modified SCR catalyst after calcination.

Example 3

In this example, NH concentration of 1 to 2mol/L₄VO₃The preparation of the solution is carried out in a constant temperature environment of 90 ℃, and the total adding amount of the ethanolamine solution is 200 ml; the temperature in the calcining process is respectively 120 ℃ and 570 ℃;

the specific procedure is as follows,

first, NH is added₄VO₃Adding into desalted water, stirring, adding 40ml ethanolamine solution at 90 deg.C under stirring to obtain NH₄VO₃After the solution is completely dissolved, the volume concentration reaches 1-2mol/L and then the solution is used as an impregnation solution for standby; putting an SCR catalyst monomer into the impregnation liquid for impregnation;

secondly, naturally drying the impregnated SCR catalyst monomer at room temperature;

finally, calcining the air-dried SCR catalyst monomer, wherein the calcining process comprises the following steps,

i), heating from room temperature to 120 ℃, wherein the heating rate is less than 3 ℃/min, and keeping the temperature at 120 ℃ for at least 24 h;

II), heating from 120 ℃ to 570 ℃, wherein the heating rate is less than 3 ℃/min, and calcining for at least 96h at 570 ℃;

III), naturally cooling the calcined SCR catalyst monomer to room temperature.

And obtaining the modified SCR catalyst after calcination.