Low-temperature SCR denitration catalyst with SiC as carrier and preparation method and application thereof
阅读说明：本技术 以SiC为载体的低温SCR脱硝催化剂及其制备方法和应用 (Low-temperature SCR denitration catalyst with SiC as carrier and preparation method and application thereof ) 是由 袁群富 辛志玲 叶凡平 彭静娜 王利克 于 2021-09-29 设计创作，主要内容包括：本发明涉及一种以SiC为载体的低温SCR脱硝催化剂及其制备方法和应用,包括以下步骤：步骤一,取SiC,加入去离子水,超声溶解,使其充分散；步骤二,将称好的锰盐溶解于去离子水中,将其逐滴加入到超声溶解的SiC溶液中,得到混合前驱体溶液；步骤三,将混合前驱体溶液暴露在空气中搅干,在烘箱中干燥,得到干燥后的前驱体；步骤四,将干燥后的前驱体进行煅烧,得到成品催化剂。与现有技术相比,本发明通过在SiC上负载金属锰扩大了催化剂的温度窗口,增大了比表面积和孔径,提高了催化剂的低温活性和催化性能,探究出了最佳负载量,最大限度地优化催化剂。(The invention relates to a low-temperature SCR denitration catalyst with SiC as a carrier, a preparation method and application thereof, and the low-temperature SCR denitration catalyst comprises the following steps: taking SiC, adding deionized water, and dissolving by ultrasonic waves to fully disperse the SiC; dissolving the weighed manganese salt in deionized water, and dropwise adding the manganese salt into the SiC solution dissolved by ultrasonic waves to obtain a mixed precursor solution; exposing the mixed precursor solution in air, stirring, and drying in an oven to obtain a dried precursor; and step four, calcining the dried precursor to obtain the finished catalyst. Compared with the prior art, the method has the advantages that the temperature window of the catalyst is enlarged by loading the metal manganese on the SiC, the specific surface area and the pore diameter are increased, the low-temperature activity and the catalytic performance of the catalyst are improved, the optimal loading capacity is explored, and the catalyst is optimized to the maximum extent.)
1. A preparation method of a low-temperature SCR denitration catalyst taking SiC as a carrier is characterized by comprising the following steps:
taking SiC, adding deionized water, and dissolving by ultrasonic waves to fully disperse the SiC;
dissolving the weighed manganese salt in deionized water, and dropwise adding the manganese salt into the SiC solution dissolved by ultrasonic waves to obtain a mixed precursor solution;
exposing the mixed precursor solution in air, stirring, and drying in an oven to obtain a dried precursor;
and step four, calcining the dried precursor to obtain the finished catalyst.
2. The preparation method of the low-temperature SCR denitration catalyst with SiC as the carrier according to claim 1, wherein in the step one, deionized water is added by using SiC powder.
3. The method for preparing the low-temperature SCR denitration catalyst with SiC as the carrier according to claim 1, wherein in the second step, the manganese salt is manganese acetate.
4. The preparation method of the low-temperature SCR denitration catalyst with SiC as the carrier according to the claim 1, wherein in the third step, the drying temperature in the oven is 120 ℃, and the drying time is 12 h.
5. The method for preparing the low-temperature SCR denitration catalyst with SiC as the carrier according to claim 1, wherein in the fourth step, the calcination temperature is 500 ℃ and the calcination time is 6 h.
6. The preparation method of the low-temperature SCR denitration catalyst with SiC as the carrier according to claim 1, wherein the loading amount of Mn is 5-15 wt%.
7. The method for preparing the low-temperature SCR denitration catalyst with SiC as the carrier according to claim 6, wherein the loading amount of Mn is 10 wt%.
8. A low-temperature SCR denitration catalyst using SiC as a carrier, which is obtained by the preparation method according to any one of claims 1 to 7.
9. Use of a catalyst as claimed in claim 8 in low temperature SCR denitration.
10. The application of the catalyst in low-temperature SCR denitration according to claim 9, wherein the Mn/SiC catalyst with the loading of 10 wt% is used at the space velocity of 40000h-1NO concentration 500mg/m3At a temperature of 225 ℃ the maximum catalytic activity of 98% is obtained, T80Temperature ofThe window is 160-320 ℃.
Technical Field
The invention relates to the field of low-temperature SCR denitration, in particular to a low-temperature SCR denitration catalyst taking SiC as a carrier and a preparation method and application thereof.
Background
The energy structure of China is mainly coal, so most domestic power stations mainly burn fossil fuel to generate thermal power, but nitrogen oxides generated by burning the fossil fuel are discharged to the atmosphere and are increased year by year, and the problems of photochemical smog, acid rain and the like are caused. The selective catalytic reduction method is the most efficient and widely applied treatment method at present. The selective oxidation-reduction reaction is abbreviated as SCR reaction, namely, NH is used under the action of a catalyst3Selectively using the reducing agent to remove NO in the pollutant gasxReduction to non-toxic N2。
At NH3In an SCR denitration system, the research and development of a denitration catalyst are key cores. The performance of the catalyst determines the efficiency of denitration reaction, and the current commercial catalyst is mainly a vanadium-based catalyst, but has a series of disadvantages of overhigh reaction temperature, poor poison resistance, high price, toxicity and the like, so that the development of the catalyst with low reaction temperature window, good poison resistance and low price is very important.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides a low-temperature SCR denitration catalyst using SiC as a carrier, and a preparation method and application thereof, and provides a denitration catalyst using SiC as a carrier, which has the advantages of large reaction temperature window, high low-temperature catalytic activity, strong water resistance and stability, no toxicity and no pollution.
The purpose of the invention can be realized by the following technical scheme:
the invention aims to protect a preparation method of a low-temperature SCR denitration catalyst taking SiC as a carrier, which comprises the following steps:
taking SiC, adding deionized water, and dissolving by ultrasonic waves to fully disperse the SiC;
dissolving the weighed manganese salt in deionized water, and dropwise adding the manganese salt into the SiC solution dissolved by ultrasonic waves to obtain a mixed precursor solution;
exposing the mixed precursor solution in air, stirring, and drying in an oven to obtain a dried precursor;
and step four, calcining the dried precursor to obtain the finished catalyst.
Further, in the first step, SiC powder is added into deionized water.
Further, in the second step, the manganese salt is manganese acetate.
Further, in the third step, the drying temperature in the oven is 120 ℃, and the drying time is 12 hours.
Furthermore, in the fourth step, the calcining temperature is 500 ℃ and the calcining time is 6 hours.
Further, the loading amount of Mn is 5 wt% to 15 wt%.
Further preferably, the loading of Mn is 10 wt%.
The second purpose of the invention is to protect the low-temperature SCR denitration catalyst which takes SiC as a carrier and is obtained by the preparation method.
The third purpose of the invention is to protect the application of the catalyst in low-temperature SCR denitration.
Further preferably, the Mn/SiC catalyst with the loading of 10 wt% is used at the space velocity of 40000h-1NO concentration 500mg/m3At a temperature of 225 ℃ the maximum catalytic activity of 98% is obtained, T80The temperature window is 160-320 ℃.
The loading amount in the technical scheme is the mass percentage of Mn element loaded on SiC.
Compared with the prior art, the invention has the following technical advantages:
(1) according to the method, the temperature window of the catalyst is enlarged by loading the metal manganese on the SiC, the specific surface area and the pore diameter are increased, the low-temperature activity and the catalytic performance of the catalyst are improved, the optimal loading capacity is explored, and the catalyst is optimized to the maximum extent.
(2) The catalyst is more stable in the reaction, and the service life of the catalyst is prolonged; and reactants in a gas phase system can be better adsorbed on the active sites on the surface of the catalyst, so that the catalytic activity is improved.
Drawings
FIG. 1: denitration performance of the SiC-supported manganese SCR catalyst in the examples.
FIG. 2: the water resistance performance of the SiC supported manganese SCR catalyst in the examples.
FIG. 3: stability performance profile of SiC supported manganese SCR catalyst in examples.
Detailed Description
The present invention will be described in detail with reference to examples. Before proceeding with the description, it is necessary to demonstrate that the following examples are only intended to illustrate the invention further and are not to be construed as limiting the scope of the invention. Accordingly, other equivalents and modifications may be made thereto by those skilled in the art without departing from the spirit and scope of the invention.
Studies have shown that, in addition to vanadium-based catalysts, other transition metals (Fe, Co, Ni, etc.) are present in NH3The SCR catalyst also has certain catalytic activity in SCR reaction, but the excellent SCR catalytic activity cannot be obtained by simply synthesizing single-component, bi-component or multi-component catalyst, and the catalyst performance can be greatly improved by reasonably and effectively designing the catalyst structure.
After long-term trials, the SiC is used as a catalyst carrier to load metal to participate in the processes of adsorption, activation, reaction, desorption and the like of the gas of the denitration reaction, and the ideal effects are found. The silicon carbide has stable chemical performance, high heat conductivity coefficient, small thermal expansion coefficient and good wear resistance. The long-time research shows that the catalyst has wide prospect when being used as a carrier for a denitration catalyst.
Based on the above, the invention aims to provide the denitration catalyst which takes SiC as a carrier and has the advantages of large reaction temperature window, high low-temperature catalytic activity, water resistance, strong stability, no toxicity and no pollution.
The specific experimental part is as follows:
example 1:
(1) taking SiC out of a beaker, adding a proper amount of deionized water, ultrasonically dissolving, and fully dissolving.
(2) The weighed amount of manganese acetate was dissolved in deionized water and added dropwise to the ultrasonically dissolved SiC solution.
(3) Exposing the mixed solution in the air, stirring to dry, and drying in an oven at 120 ℃ for 12 h.
(4) And putting the dried sample into a muffle furnace, and calcining for 6h at 500 ℃ to obtain the catalyst.
Evaluation results of the activity of the catalyst:
when the idle speed is 40000h, the catalyst is loaded with 5 percent of Mn-1NO concentration 500mg/m3The highest catalytic activity of 82% is obtained at a temperature of 250 ℃, T80The temperature window of (1) is 225-275 ℃, and the temperature window range is narrower.
Example 2:
(1) taking SiC out of a beaker, adding a proper amount of deionized water, ultrasonically dissolving, and fully dissolving.
(2) The weighed amount of manganese acetate was dissolved in deionized water and added dropwise to the ultrasonically dissolved SiC solution.
(3) Exposing the mixed solution in the air, stirring to dry, and drying in an oven at 120 ℃ for 12 h.
(4) And putting the dried sample into a muffle furnace, and calcining for 6h at 500 ℃ to obtain the catalyst.
Evaluation results of the activity of the catalyst:
the catalyst with 10 percent of Mn is loaded at the idle speed of 40000h-1NO concentration 500mg/m3The highest catalytic activity is 98% at 225 ℃, T80The temperature window is 160-320 ℃, and the temperature window range is wider.
Referring to fig. 2 and 3, the second catalyst loaded with 10% of Mn is at the idle speed of 40000h-1NO concentration 500mg/m3At a temperature of 225 ℃, 5 vol% H is introduced2O is kept stable at the denitration rate of 98% for 2.25h and can still return to the denitration rate of 98% after water supply is stopped. In addition, the conversion rate of the catalyst in the embodiment is more stable within 150 h.
Example 3:
(1) taking SiC out of a beaker, adding a proper amount of deionized water, ultrasonically dissolving, and fully dissolving.
(2) The weighed amount of manganese acetate was dissolved in deionized water and added dropwise to the ultrasonically dissolved SiC solution.
(3) Exposing the mixed solution in the air, stirring to dry, and drying in an oven at 120 ℃ for 12 h.
(4) And putting the dried sample into a muffle furnace, and calcining for 6h at 500 ℃ to obtain the catalyst.
Evaluation results of the activity of the catalyst:
the catalyst with 15 percent of Mn is loaded at the idle speed of 40000h-1NO concentration 500mg/m3The highest catalytic activity was 97% at a temperature of 200 ℃ and T80The temperature window is 160-320 ℃, and the temperature window range is wider.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.