CN114558614B - La modified Cu-Ce/TNU-9 denitration catalyst and preparation method thereof - Google Patents

La modified Cu-Ce/TNU-9 denitration catalyst and preparation method thereof Download PDF

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CN114558614B
CN114558614B CN202210164429.9A CN202210164429A CN114558614B CN 114558614 B CN114558614 B CN 114558614B CN 202210164429 A CN202210164429 A CN 202210164429A CN 114558614 B CN114558614 B CN 114558614B
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tnu
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李智芳
杨长龙
崔金星
杨健
马媛媛
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Qiqihar University
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Abstract

The invention relates to the technical field of environmental catalysis and atmospheric pollution control, and provides a La modified Cu-Ce/TNU-9 denitration catalyst and a preparation method thereof. The La modified Cu-Ce/TNU-9 denitration catalyst is prepared by adopting an ion exchange method, and the catalytic activity of the catalyst is improved and the denitration temperature window is widened by controlling the introduction sequence and the roasting sequence of Cu, Ce and La; in addition, the invention adopts H/TNU-9 as the carrier of the catalyst, adopts La, Cu and Ce as the active components, and ensures that the obtained denitration catalyst has excellent denitration efficiency and H resistance in a wider temperature window by matching the specific active components with the carrier 2 O and SO 2 And (4) performance.

Description

La modified Cu-Ce/TNU-9 denitration catalyst and preparation method thereof
Technical Field
The invention relates to the technical field of environmental catalysis and atmospheric pollution control, in particular to a La modified Cu-Ce/TNU-9 denitration catalyst and a preparation method thereof.
Background
Nitrogen Oxides (NO) emitted from coal-fired power plants, plant boilers, and the like x ＝NO+NO 2 ) Is considered to be one of the main atmospheric pollutants, and causes acid rain, ozone, PM2.5, dust haze, and the like. NO is accelerated with the development of industry x The need to improve air quality is also growing, and therefore, there is a need to control nox emissions.
By NH 3 Selective catalytic reduction (NH) as a reducing agent 3 -SCR) technology is one of the most commonly used denitration methods. Conventional NH 3 The SCR technology adopts a V-based catalyst for catalysis, and the V-based catalyst has higher NO at 300-400 DEG C x But the conversion rate is not ideal in low-temperature denitration performance, so that the method is only suitable for thermal power plants. When in useIn the past, the flue gas temperature of part of coal-fired units in China is usually lower than 300 ℃, and V-based catalysts are not suitable for coal-fired units producing low-temperature flue gas. In addition, V-based catalysts are toxic and are toxic in H 2 O and SO 2 Are easily inactivated in the presence. Therefore, the denitration temperature window of the catalyst is widened, and the excellent H resistance is developed 2 O and SO 2 V-free denitration catalyst of (1) for NH 3 Development and application of SCR technology is of great importance.
Disclosure of Invention
In view of the above, the invention provides a La modified Cu-Ce/TNU-9 denitration catalyst and a preparation method thereof. The La modified Cu-Ce/TNU-9 denitration catalyst provided by the invention has excellent denitration efficiency in a wider temperature window, and N 2 High selectivity, H resistance 2 O and SO 2 The performance is good.
In order to achieve the above object, the present invention provides the following technical solutions:
a preparation method of a La modified Cu-Ce/TNU-9 denitration catalyst comprises the following steps:
mixing H/TNU-9 and a copper salt aqueous solution for copper ion exchange, and performing first roasting on an exchange product to obtain a Cu/TNU-9 catalyst;
mixing the Cu/TNU-9 catalyst and a cerium salt aqueous solution for cerium ion exchange to obtain cerium ion loaded Cu/TNU-9;
and mixing the cerium ion-loaded Cu/TNU-9 with a lanthanum salt aqueous solution to perform lanthanum ion exchange, and performing second roasting on an exchange product to obtain the La modified Cu-Ce/TNU-9 denitration catalyst.
Preferably, the copper salt is one or more of copper nitrate, copper chloride and copper acetate; the cerium salt is cerium nitrate.
Preferably, the temperature of the copper ion exchange is 70-90 ℃, the frequency of the copper ion exchange is 3 times, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, wherein the time of each exchange is 16-32 h; in the single copper ion exchange, the weight of the used copper salt is 1-3% of the weight of H/TNU-9;
the temperature of the cerium ion exchange is 70-90 ℃, the frequency of the cerium ion exchange is 3 times, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, wherein the time of each exchange is 16-32 h; in the single cerium ion exchange, the weight of the cerium salt used is 2-4% of the weight of the Cu/TNU-9 catalyst.
Preferably, the temperature of the first roasting is 450-550 ℃, and the time is 3-5 hours.
Preferably, the temperature of the lanthanum ion exchange is room temperature; the frequency of lanthanum ion exchange is 1, the time of lanthanum ion exchange is 16-32 h, and the liquid-solid ratio is 25-100 mL: 1 g; the weight of the lanthanum salt in the lanthanum salt aqueous solution is 0.3-5% of the weight of the Cu/TNU-9 loaded with the cerium ions.
Preferably, the temperature of the second roasting is 450-550 ℃, and the time is 3-5 h.
Preferably, the preparation method of the H/TNU-9 comprises the following steps: and mixing the Na/TNU-9 with an ammonium nitrate aqueous solution for ammonium ion exchange, and carrying out third roasting on an exchange product to obtain H/TNU-9.
Preferably, the temperature of the ammonium ion exchange is 85-95 ℃; the number of times of ammonium ion exchange is 2, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, and the time of each exchange is 3-6 h.
The invention also provides the La modified Cu-Ce/TNU-9 denitration catalyst prepared by the preparation method in the scheme, which comprises a carrier and an active component, wherein the carrier is H/TNU-9, and the active component comprises La, Cu and Ce.
The invention provides a preparation method of a La modified Cu-Ce/TNU-9 denitration catalyst, which comprises the following steps: mixing H/TNU-9 and a copper salt aqueous solution for copper ion exchange, and performing first roasting on an exchange product to obtain a Cu/TNU-9 catalyst; mixing the Cu/TNU-9 catalyst and a cerium salt aqueous solution for cerium ion exchange to obtain cerium ion loaded Cu/TNU-9; and mixing the cerium ion-loaded Cu/TNU-9 with a lanthanum salt aqueous solution to perform lanthanum ion exchange, and performing second roasting on an exchange product to obtain the La modified Cu-Ce/TNU-9 denitration catalyst. The method adopts an ion exchange method to prepare the La modified Cu-Ce/TNU-9 denitration catalyst, wherein Cu is introduced through copper ion exchange, and Ce and La are sequentially introduced after first roastingThe introduction sequence of Cu, Ce and La can make the distribution of the active components in the carrier more uniform; according to the invention, Ce and La are introduced after the first roasting, so that the loss of the Cu component can be avoided, and the property of the catalyst is ensured. The invention can improve the catalytic activity and N of the catalyst by controlling the introduction sequence and the roasting sequence of Cu, Ce and La 2 Selectivity, widens the denitration temperature window and ensures excellent SO resistance 2 In addition, TNU-9 adopted by the invention is high-silicon zeolite, and the hydrophobicity is strong, so that the obtained catalyst also has excellent H resistance 2 And (4) O performance.
The invention also provides the La modified Cu-Ce/TNU-9 denitration catalyst prepared by the preparation method, which comprises a carrier and an active component, wherein the carrier is H/TNU-9, and the active component comprises La, Cu and Ce. The denitration catalyst carrier provided by the invention is H/TNU-9, the H/TNU-9 molecular sieve has a three-dimensional ten-ring cross structure, a larger cage is also contained in a pore channel, and the denitration catalyst carrier has excellent hydrophobicity and hydrothermal stability. In addition, the active components of the denitration catalyst provided by the invention comprise La, Cu and Ce, and when denitration is carried out, La promotes redox circulation in the catalyst:
Figure BDA0003515786060000031
promotes the transfer of electrons and thus the oxidation of NO to NO 2 Promoting the occurrence of fast SCR. Meanwhile, the introduction of La can enable more isolated copper ions to exist, can also improve the acidity and the oxidation-reduction property of the surface of the catalyst, and is favorable for generating oxygen vacancies, thereby improving the denitration activity of the catalyst. The invention adopts specific active components and carriers to be matched for use, so that the obtained denitration catalyst has excellent denitration efficiency in a wider temperature window, and N is 2 High selectivity, H resistance 2 O and SO 2 The performance is good.
Drawings
FIG. 1 is an XRD pattern of Na/TNU-9(a), H/TNU-9(b), Cu/TNU-9(c), Ce-Cu/TNU-9(d) and La-Ce-Cu/TNU-9 (e);
FIG. 2 is an SEM image of H/TNU-9(a), Cu/TNU-9(b), Ce-Cu/TNU-9(c), La-Ce-Cu/TNU-9) (d);
FIG. 3 is a SEM-Mapping chart of Cu/TNU-9(a), Ce-Cu/TNU-9(b) and La-Ce-Cu/TNU-9 (c);
FIG. 4 is an XPS plot of Cu/TNU-9(a), Ce-Cu/TNU-9(b) and La-Ce-Cu/TNU-9 (c);
FIG. 5 is a Ce-3d plot of Ce-Cu/TNU-9(a), La-Ce-Cu/TNU-9 (b);
FIG. 6 is a diagram of O1s for Cu/TNU-9(a), Ce-Cu/TNU-9(b), and La-Ce-Cu/TNU-9 (c);
FIG. 7 is a La-3d diagram of La-Ce-Cu/TNU-9;
FIG. 8 shows NH of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 3 -a TPD map;
FIG. 9 shows H for Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 2 -a TPR map;
FIG. 10 shows NH of Cu/TNU-9, Ce-Cu/TNU-9, La-Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9-I 3 -SCR activity test results;
FIG. 11 shows N for Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 2 A selective test result;
FIG. 12 shows the H resistance of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 at 250 ℃ 2 O and SO 2 Performance test results;
FIG. 13 shows the H resistance of La-Ce-Cu/TNU-9 at 350 deg.C 2 O and SO 2 And (5) performance test results.
Detailed Description
The invention provides a preparation method of a La modified Cu-Ce/TNU-9 denitration catalyst, which comprises the following steps:
mixing H/TNU-9 and a copper salt aqueous solution for copper ion exchange, and performing first roasting on an exchange product to obtain a Cu/TNU-9 catalyst;
mixing the Cu/TNU-9 catalyst and a cerium salt aqueous solution to perform cerium ion exchange, and loading the cerium ion Cu/TNU-9;
and mixing the cerium ion-loaded Cu/TNU-9 with a lanthanum salt aqueous solution to perform lanthanum ion exchange, and performing second roasting on an exchange product to obtain the La modified Cu-Ce/TNU-9 denitration catalyst.
The invention mixes H/TNU-9 and copper salt water solution to exchange copper ion, to obtain the exchange product. In the invention, the preparation method of the H/TNU-9 is preferably as follows: and mixing Na/TNU-9 and an ammonium nitrate aqueous solution for ammonium ion exchange, and carrying out third roasting on an exchange product to obtain H/TNU-9. In the invention, the temperature of the ammonium ion exchange is preferably 85-95 ℃, and more preferably 90 ℃; the number of times of ammonium ion exchange is preferably 2, and the liquid-solid ratio of each exchange is preferably 50-150 mL: 1g, more preferably 100 mL: 1g, the time of each exchange is preferably 3-6 h, and more preferably 5 h; the concentration of the ammonium nitrate aqueous solution is preferably 0.4-0.6 mmol/L, and more preferably 0.5 mmol/L. In a particular embodiment of the invention, said ammonium ion exchange is particularly preferably: mixing Na/TNU-9 and an ammonium nitrate aqueous solution, stirring for 3-6 hours at 85-95 ℃, filtering, washing with distilled water and drying after stirring, mixing the dried product and the ammonium nitrate aqueous solution, stirring for 3-6 hours at 85-95 ℃, filtering, washing with distilled water and drying again, and thus completing ammonium ion exchange twice. In the invention, the temperature of the third roasting is preferably 450-550 ℃, more preferably 500 ℃, and the time of the third roasting is preferably 3-5 h, more preferably 4 h; the third calcination is preferably carried out under air conditions. The source of the Na/TNU-9 is not particularly required in the present invention, and commercially available products well known to those skilled in the art can be used. According to the invention, partial sodium ions in Na/TNU-9 are exchanged into ammonium ions through ammonium ion exchange, and H/TNU-9 is obtained through third roasting.
After H/TNU-9 is obtained, H/TNU-9 and a copper salt aqueous solution are mixed for copper ion exchange; the copper salt is preferably one or more of copper nitrate, copper chloride and copper acetate, and the copper nitrate is Cu (NO) 3 ) 2 ·3H 2 O。
In the invention, the temperature of the copper ion exchange is preferably 70-90 ℃, more preferably 80 ℃, the frequency of the copper ion exchange is preferably 3 times, and the liquid-solid ratio of each exchange is preferably 50-150 mL: 1g, more preferably 100 mL: 1g, the time of each exchange is preferably 16-32 h, and more preferably 24 h; in the single copper ion exchange, the weight of the copper salt is preferably 1-3%, more preferably 1.5-2.5%, and even more preferably 2% of the weight of H/TNU-9. After each ion exchange, the product obtained by the exchange is preferably washed and dried in sequence, and then subjected to the next ion exchange. According to the invention, the residual sodium ions in H/TNU-9 are exchanged into copper ions through copper ion exchange, and the amount of the copper ions entering the molecular sieve carrier is controlled by controlling the frequency of copper ion exchange, so that the catalyst is ensured to have the best denitration performance.
After the last copper ion exchange is finished, the obtained exchange product is sequentially washed and dried, and then is subjected to first roasting to obtain the Cu/TNU-9 catalyst. In the invention, the first roasting temperature is preferably 450-550 ℃, more preferably 500 ℃, and the first roasting time is preferably 3-5 h, more preferably 4 h; the first calcination is preferably carried out under air conditions. According to the invention, copper is firmly and uniformly loaded on the molecular sieve through the first roasting, so that the loss of copper ions during subsequent cerium ion exchange and lanthanum ion exchange is prevented.
After the Cu/TNU-9 catalyst is obtained, the Cu/TNU-9 catalyst and a cerium salt aqueous solution are mixed for cerium ion exchange, and the Cu/TNU-9 loaded with cerium ions is obtained. In the present invention, the cerium salt is preferably cerium nitrate, specifically Ce (NO) 3 ) 2 ·6H 2 O; the number of times of cerium ion exchange is preferably 3, and the liquid-solid ratio of each exchange is preferably 50-150 mL: 1g, more preferably 100 mL: 1g, the time of each exchange is preferably 16-32 h, and more preferably 24 h; in the single cerium ion exchange, the weight of the cerium salt used is preferably 2 to 4%, more preferably 2.5 to 3.5%, and still more preferably 3% of the weight of the Cu/TNU-9 catalyst. After each ion exchange, the product obtained by the exchange is preferably washed and dried in sequence, and then the next ion exchange is carried out. The invention exchanges partial sodium ions left in H/TNU-9 into cerium ions through cerium ion exchange, and controls by controlling the times of cerium ion exchangeThe amount of metal ions entering the molecular sieve carrier ensures that the catalyst has the best denitration performance.
After the cerium ion-loaded Cu/TNU-9 is obtained, the method mixes the cerium ion-loaded Cu/TNU-9 with a lanthanum salt aqueous solution for lanthanum ion exchange, and carries out second roasting on the obtained exchange product to obtain the La modified Cu-Ce/TNU-9 denitration catalyst. In the present invention, the temperature of the lanthanum ion exchange is preferably room temperature; the frequency of lanthanum ion exchange is preferably 1, the time of lanthanum ion exchange is preferably 16-32 h, more preferably 24h, and the liquid-solid ratio is preferably 25-100 mL: 1g, more preferably 50 mL: 1 g; the lanthanum salt is preferably lanthanum nitrate, in particular La (NO) 3 ·6H 2 O; the weight of the lanthanum salt in the lanthanum salt aqueous solution is preferably 0.5-3%, more preferably 1-2.5%, and even more preferably 2% of the weight of the cerium ion-loaded Cu/TNU-9. The method comprises the steps of exchanging residual sodium ions in the H/TNU-9 molecular sieve for lanthanum ions through lanthanum ion exchange; after the lanthanum ion exchange is completed, the obtained product is preferably washed and dried in sequence, and then subjected to the second calcination.
In the invention, the second roasting temperature is preferably 450-550 ℃, more preferably 500 ℃, and the second roasting time is preferably 3-5 h, more preferably 4 h; the second calcination is preferably carried out under air conditions. According to the invention, through the second roasting, the La, Ce and the molecular sieve are combined more firmly and distributed more uniformly.
The invention also provides the La modified Cu-Ce/TNU-9 denitration catalyst prepared by the preparation method in the scheme, which comprises a carrier and an active component, wherein the carrier is H/TNU-9, and the active component comprises La, Cu and Ce.
In the invention, the La modified Cu-Ce/TNU-9 denitration catalyst has excellent NH in a temperature window of 200-450 DEG C 3 SCR activity and N 2 Selectivity and excellent H resistance 2 O and SO 2 And (4) sex.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Example 1
(1) Mixing 1g of Na/TNU-9 molecular sieve and 100mL of 0.5mmol/L ammonium nitrate aqueous solution, stirring for 5H at 90 ℃, then sequentially filtering, washing with distilled water and drying, performing ammonium ion exchange on the dried product again (namely performing ammonium ion exchange twice in total), sequentially filtering, washing with distilled water and drying after the exchange is finished, and roasting the obtained product for 4H at 500 ℃ in the air to obtain the H/TNU-9 molecular sieve.
(2) A molecular sieve of 1g H/TNU-9 was added to a solution containing 0.02g Cu (NO) 3 ) 2 ·3H 2 And (2) uniformly mixing the O in 100mL of aqueous solution, stirring for 24h at 80 ℃, then sequentially filtering, washing and drying, repeating copper ion exchange for 2 times on the dried product (namely, carrying out three times of copper ion exchange), and roasting the obtained exchange product for 4h at 500 ℃ to obtain the Cu/TNU-9.
(3) 1g of Cu/TNU-9 was added to a solution containing 0.03g of Ce (NO) 3 ) 2 ·6H 2 And (2) uniformly mixing the components in 100mL of O aqueous solution, stirring for 24h at 80 ℃, then sequentially filtering, washing and drying, repeating cerium ion exchange for 2 times (namely, carrying out three times of cerium ion exchange), washing and drying the obtained product after the third time of cerium ion exchange, and thus obtaining the cerium ion-loaded Cu/TNU-9.
(4) 1g of cerium ion-loaded Cu/TNU-9 was added to a solution containing 0.02g of La (NO) 3 ) 3 ·6H 2 Stirring the mixture for 24 hours at room temperature in 50mL of O aqueous solution, then sequentially filtering, washing and drying, and roasting the dried product for 4 hours at 500 ℃ to obtain the La modified Cu-Ce/TNU-9 denitration catalyst which is marked as La-Ce-Cu/TNU-9.
Comparative example 1
The Cu/TNU-9 obtained in step (2) of example 1 was used as comparative example 1.
Comparative example 2
Otherwise, in the same manner as in steps (1) to (3) of example 1, only in step (3), cerium ion-supported Cu/TNU-9 obtained after drying was calcined at 500 ℃ for 4 hours to obtain a denitration catalyst, designated as Ce-Cu/TNU-9.
Comparative example 3
(1) 1g H/TNU-9 molecular sieve (H/TNU-9 molecular sieve was prepared by the same method as in example 1) was added to a solution containing 0.02g of Cu (NO) 3 ) 2 ·3H 2 Mixing O in 100mL of water solution, stirring for 24h at 80 ℃, washing, drying, repeating copper ion exchange for 2 times (namely carrying out copper ion exchange for three times), washing and drying after the third exchange is finished, and not roasting.
(2) 1g of the sample obtained in step (2) was added to a solution containing 0.03g of Ce (NO) 3 ) 3 ·6H 2 O and 0.02g La (NO) 3 ) 3 ·6H 2 Stirring the mixture in 50mL of O aqueous solution at room temperature for 24h, washing, drying, repeating cerium-lanthanum ion exchange for 2 times (namely carrying out three times of cerium-lanthanum ion exchange), wherein the conditions of each time of ion exchange are the same as those of the first time, washing and drying the obtained product after the third time of ion exchange, and roasting at 500 ℃ for 4h to obtain the denitration catalyst, wherein the obtained catalyst is marked as La-Ce-Cu/TNU-9-I.
And (3) performance testing:
1. characterization of
(1) XRD test
XRD tests were carried out on Na/TNU-9, H/TNU-9 obtained in step (1) of example 1, Cu/TNU-9 prepared in comparative example 1, Ce-Cu/TNU-9 prepared in comparative example 2, and La-Ce-Cu/TNU-9 prepared in example 1, and the results are shown in FIG. 1, wherein (a) is Na/TNU-9, (b) is H/TNU-9, (c) is Cu/TNU-9, (d) is Ce-Cu/TNU-9, and (e) is La-Ce-Cu/TNU-9. As can be seen from FIG. 1, the La-Ce-Cu/TNU-9 prepared by the invention contains La, Ce and Cu elements.
(2) SEM test
Scanning electron microscope tests were carried out on H/TNU-9 obtained in step (1) of example 1, Cu/TNU-9 prepared in comparative example 1, Ce-Cu/TNU-9 prepared in comparative example 2 and La-Ce-Cu/TNU-9 prepared in example 1, and the results are shown in FIG. 2, in which (a) is H/TNU-9, (b) is Cu/TNU-9, (c) is Ce-Cu/TNU-9 and (d) is La-Ce-Cu/TNU-9. As can be seen from FIG. 2, the morphology of the TNU-9 carrier after loading did not change significantly.
FIG. 3 is SEM-Mapping graphs of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9, wherein (a) is Cu/TNU-9, (b) is Ce-Cu/TNU-9, and (c) is La-Ce-Cu/TNU-9. As can be seen from FIG. 3, the La-Ce-Cu/TNU-9 prepared by the invention contains Cu, Ce and La elements, and the elements are uniformly distributed (the Si and Al elements come from H/TNU-9 molecular sieves).
(3) XPS test
FIG. 4 is an XPS plot of Cu/TNU-9, Ce-Cu/TNU-9, and La-Ce-Cu/TNU-9, wherein (a) is Cu/TNU-9, (b) is Ce-Cu/TNU-9, and (c) is La-Ce-Cu/TNU-9;
FIG. 5 is a Ce-3d plot of Ce-Cu/TNU-9, La-Ce-Cu/TNU-9, wherein (a) is Ce-Cu/TNU-9 and (b) is La-Ce-Cu/TNU-9;
FIG. 6 is a diagram of O1s for Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9, wherein (a) is Cu/TNU-9, (b) is Ce-Cu/TNU-9, and (c) is La-Ce-Cu/TNU-9;
FIG. 7 shows La-3d of La-Ce-Cu/TNU-9.
The relative contents of the elements in the catalyst were calculated from the peak areas in the XPS spectra, and the results are shown in table 1.
TABLE 1 relative content of the respective elements in the catalyst
Figure BDA0003515786060000091
As can be seen from the data in FIGS. 4 to 7 and Table 1, Cu is present in the La-Ce-Cu/TNU-9 catalyst prepared according to the present invention 2+ 、Cu + 、Ce 3+ 、Ce 4+ 、O α (adsorbing oxygen) and O β (lattice oxygen), and Ce 3+ Is higher than the other two catalysts. Redox cycle
Figure BDA0003515786060000093
Electron transfer is promoted to further promote the conversion of nitric oxide to nitrogen dioxide, resulting in the occurrence of a rapid SCR reaction. Further, Ce 3+ More oxygen vacancies can be generated, and the reaction activity is improved. O is α Is favorable for oxidizing NO into NO 2 Thereby improving low temperature activity by rapid SCR.
(4)NH 3 TPD and H 2 -TPR test
FIG. 8 shows NH of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 3 -a TPD map;
FIG. 9 shows H for Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 2 -a TPR map;
the ammonia and hydrogen consumption for Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 are shown in Table 2:
TABLE 2 NH of the respective catalysts 3 And H 2 Consumption of
Figure BDA0003515786060000092
Figure BDA0003515786060000101
As can be seen from the data in FIGS. 8 to 9 and Table 2, the introduction of La improves the acidity and the oxidation-reduction property of the catalyst surface.
(5) Test for catalytic Performance
The catalytic performance test is carried out on Cu/TNU-9, Ce-Cu/TNU-9, La-Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9-I, the dosage of the catalyst is 0.3g, and the Nitrogen Oxide (NO) is x ) Flow rate of gas 100mL/min, Nitrogen Oxide (NO) x ) The composition of the gas is: 500ppmNH 3 ，500ppmNO，5％O 2 ，N 2 Is the balance gas. Filling the catalyst in a fixed bed reactor, introducing mixed gas into the fixed bed reactor, and testing NO at the gas outlet x Content, calculation of NO x Conversion of (2) and N 2 The selectivity is measured at 150 deg.C, 200 deg.C, 250 deg.C, 300 deg.C, 350 deg.C, 400 deg.C, and 450 deg.C, respectively.
The results are shown in FIGS. 10 to 11, in which FIG. 10 shows NH of Cu/TNU-9, Ce-Cu/TNU-9, La-Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9-I 3 SCR Activity test results, FIG. 11 is the N of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 2 And (5) selecting a test result. According to the figure10 and 11 show that the La-Ce-Cu/TNU-9 denitration catalyst prepared by the invention has excellent NH within a temperature window of 200-450 DEG C 3 SCR activity, in particular NO at 200 to 400 ℃ x The conversion rate of the catalyst can almost reach 100%, and the N content of the La-Ce-Cu/TNU-9 denitration catalyst is 200-450 DEG C 2 The selectivity can reach 100 percent; however, the catalytic effects of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9-I at low temperature are poor, and the La-Ce-Cu/TNU-9-I and the method only have difference in the ion introduction sequence and the roasting sequence, which shows that the Cu, Ce and La ions are introduced according to the method of the invention and are roasted according to the sequence of the invention, so that the catalytic activity of the catalyst can be improved, and the denitration temperature window of the catalyst is widened.
(7) anti-H 2 O and SO 2 Performance test
anti-H of Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 2 O and SO 2 The performance test shows that the dosage of the catalyst is 0.3g and the Nitrogen Oxide (NO) x ) Flow rate of gas 100mL/min, Nitrogen Oxide (NO) x ) The composition of the gas is: 500ppmNH 3 ，500ppmNO，100ppmSO 2 ，5％O 2 ，10％H 2 O，N 2 Is the balance gas. Filling the catalyst in a fixed bed reactor, introducing mixed gas into the fixed bed reactor, and testing NO at the gas outlet x Content, calculation of NO x Conversion of (2) and N 2 The selectivity and the test temperature are respectively 250 ℃.
The test temperature is increased to 350 ℃, other conditions are consistent, and La-Ce-Cu/TNU-9 is tested for resisting H 2 O and SO 2 Performance, furthermore, in this test, the starting gas was H-free 2 O and SO 2 NO of x Mixture (composition and NO used in the catalytic Performance test) x The mixed gas is consistent), when the catalytic reaction is carried out for 2 hours, the reaction gas is replaced by H 2 O and SO 2 NO of x The mixed gas is catalyzed to react for 10H, and the reaction gas is replaced by the gas without H 2 O and SO 2 NO of x And (4) mixing the gases.
The obtained results are shown in FIGS. 12-13, in which FIG. 12 is Cu/TNU-9, Ce-Cu/TNU-9 and La-Ce-Cu/TNU-9 are H-resistant at 250 deg.C 2 O and SO 2 The results of the performance test are shown in FIG. 13, which is the H resistance of La-Ce-Cu/TNU-9 at 350 deg.C 2 O and SO 2 And (5) performance test results. As can be seen from FIG. 12, La-Ce-Cu/TNU-9 has excellent H resistance at 250 deg.C 2 O and SO 2 Performance in H 2 O and SO 2 In the presence of a high content of NO x Conversion rate; furthermore, it can be seen from FIG. 13 that the catalyst was replaced with H-containing catalyst at 250 ℃ in the case of La-Ce-Cu/TNU-9 2 O and SO 2 NO of x After mixing with gas, NO x The conversion of (A) is slightly reduced, but can be maintained at about 90% until H is removed 2 O and SO 2 NO of x After mixing with gas, NO x The conversion rate is increased to about 100 percent again, which shows that the La-Ce-Cu/TNU-9 denitration catalyst prepared by the invention has excellent H resistance 2 O and SO 2 And (4) performance.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.

Claims (9)

1. A preparation method of a La modified Cu-Ce/TNU-9 denitration catalyst is characterized by comprising the following steps:
mixing H/TNU-9 and a copper salt aqueous solution for copper ion exchange, and performing first roasting on an exchange product to obtain a Cu/TNU-9 catalyst;
mixing the Cu/TNU-9 catalyst and a cerium salt aqueous solution for cerium ion exchange to obtain cerium ion loaded Cu/TNU-9;
and mixing the cerium ion-loaded Cu/TNU-9 with a lanthanum salt aqueous solution to perform lanthanum ion exchange, and performing second roasting on an exchange product to obtain the La modified Cu-Ce/TNU-9 denitration catalyst.
2. The preparation method according to claim 1, wherein the copper salt is one or more of copper nitrate, copper chloride and copper acetate; the cerium salt is cerium nitrate.
3. The preparation method according to claim 2, wherein the temperature of the copper ion exchange is 70-90 ℃, the frequency of the copper ion exchange is 3 times, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, wherein the time of each exchange is 16-32 h; in the single copper ion exchange, the weight of the copper salt is 1-3% of the weight of H/TNU-9;
the temperature of the cerium ion exchange is 70-90 ℃, the frequency of the cerium ion exchange is 3 times, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, wherein the time of each exchange is 16-32 h; in the single cerium ion exchange, the weight of the cerium salt used is 2-4% of the weight of the Cu/TNU-9 catalyst.
4. The preparation method according to claim 1, wherein the temperature of the first roasting is 450-550 ℃ and the time is 3-5 h.
5. The method of claim 1, wherein the temperature of the lanthanum ion exchange is room temperature; the lanthanum ion exchange frequency is 1, the lanthanum ion exchange time is 16-32 h, and the liquid-solid ratio is 25-100 mL: 1g of a compound; the weight of the lanthanum salt in the lanthanum salt aqueous solution is 0.3-5% of the weight of the Cu/TNU-9 loaded with the cerium ions.
6. The preparation method according to claim 1, wherein the temperature of the second roasting is 450 to 550 ℃ and the time is 3 to 5 hours.
7. The process according to claim 1 or 3, wherein the H/TNU-9 is prepared by: and mixing Na/TNU-9 and an ammonium nitrate aqueous solution for ammonium ion exchange, and carrying out third roasting on an exchange product to obtain H/TNU-9.
8. The method according to claim 7, wherein the temperature of the ammonium ion exchange is 85 to 95 ℃; the number of times of ammonium ion exchange is 2, and the liquid-solid ratio of each exchange is 50-150 mL: 1g, and the time of each exchange is 3-6 h.
9. The La modified Cu-Ce/TNU-9 denitration catalyst prepared by the preparation method of any one of claims 1-8 comprises a carrier and an active component, wherein the carrier is H/TNU-9, and the active component comprises La, Cu and Ce.
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