CN111097498A

CN111097498A - CH4-SCR denitration catalyst, preparation method thereof and exhaust gas denitration method

Info

Publication number: CN111097498A
Application number: CN201911400365.2A
Authority: CN
Inventors: 朱荣淑; 丁然; 朱满玉
Original assignee: Shenzhen Graduate School Harbin Institute of Technology
Current assignee: Shenzhen Graduate School Harbin Institute of Technology
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-05-05
Anticipated expiration: 2039-12-30
Also published as: CN111097498B

Abstract

The invention discloses a CH₄-SCR denitration catalyst, method for preparing same, and exhaust gas denitration method, CH₄-the component of the SCR denitration catalyst comprises an H-Beta molecular sieve carrier, indium and a metal oxide, wherein the indium is loaded on the H-Beta molecular sieve carrier, and the metal oxide is selected from Ga₂O₃、Fe₂O₃、NiO、CeO₂With Co₃O₄Combinations of (a) and (b). From above by Ga₂O₃、Fe₂O₃、NiO、CeO₂ToOne kind of C and Co₃O₄The addition of the metal oxide can obviously improve the sulfur resistance and water resistance of the catalyst and improve the denitration rate of the catalyst.

Description

CH4-SCR denitration catalyst, preparation method thereof and exhaust gas denitration method

Technical Field

The invention relates to the technical field of catalysts, in particular to a CH₄An SCR denitration catalyst, a preparation method thereof and an exhaust gas denitration method.

Background

The nitrogen oxide is one of main pollutants in the atmosphere, and the nitrogen oxide can not only cause damage to the respiratory organs of human bodies, but also cause the environmental problems of serious harm such as optical smoke, acid rain, ozone cavities and the like. The method mainly comes from the combustion of fossil fuels, and the manufacturing industry, the power production and the transportation are main nitrogen oxide emission sources, and in order to achieve the expected nitrogen oxide emission reduction target and optimize the atmospheric quality, besides strictly controlling the emission, the method is very important to develop a practical and efficient denitrification technology.

By NH₃The Selective Catalytic Reduction (SCR) method which is a reducing agent is a mature technology with wide application and higher removal efficiency at present. But NH₃The paint is toxic and corrosive, and has the problems of leakage, secondary pollution and the like in the transportation and use processes; conventional NH₃Vanadium oxide contained in the SCR denitration catalyst V-W/Ti catalyst has high toxicity and has great harm to human body and environmental health; and the ammonium salt generated in the denitration reaction process can block the pipeline, even can cause explosion, and has potential safety hazard. Therefore, new reducing agents are always sought to replace NH₃And an environment-friendly catalyst is developed.

CH₄Has the advantages of abundant resources, wide sources, low price, convenient transportation and storage, and the like, has very excellent economic value in Selective Catalytic Reduction (SCR), and is CH₄To replace NH₃The method brings possibility as a reducing agent of a Selective Catalytic Reduction (SCR) method. At present, CH₄The SCR technology has become a research hotspot for scholars at home and abroad. Among them, H-Beta molecular sieve supported indium catalysts (i.e., In/H-Beta catalysts) are attracting much attention due to their high denitration efficiency, but In/H-Beta catalysts have poor sulfur and water resistance and are severely deactivated under the condition of containing sulfur and water; in practical application, the flue gas often contains water and sulfur dioxide with certain concentration, so that the key for applying the catalyst to the practical application is to improve the sulfur resistance and water resistance of the In/H-Beta catalyst.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a CH₄-SCR denitration catalyst and preparation method and application thereofThe waste gas denitration method can improve the sulfur-resistant and water-resistant performance and the denitration rate of the In/H-Beta catalyst, and has high denitration efficiency.

The technical scheme adopted by the invention is as follows:

in a first aspect of the present invention, a CH is provided₄-SCR denitration catalyst, said CH₄-the components of the SCR denitration catalyst comprise an H-Beta molecular sieve support, indium and a metal oxide, the indium being supported on the H-Beta molecular sieve support;

the metal oxide is selected from Ga₂O₃、Fe₂O₃、NiO、CeO₂With Co₃O₄Combinations of (a) and (b).

According to some embodiments of the invention, the metal oxide is selected from Ga₂O₃、Fe₂O₃With Co₃O₄Combinations of (a) and (b).

According to some embodiments of the invention, the metal oxide is selected from Ga₂O₃And Co₃O₄Combinations of (a) and (b).

According to some embodiments of the invention, the metal oxide is selected from the group consisting of (1-4) by mass: 1 Co₃O₄And Ga₂O₃. Preferably, the metal oxide is selected from the group consisting of metal oxides having a mass ratio of 4: 1 Co₃O₄And Ga₂O₃。

According to some embodiments of the invention, the mass ratio of the metal oxide to the H-Beta molecular sieve support is 1: (2-8). Preferably, the mass ratio of the metal oxide to the H-Beta molecular sieve carrier is 1: 4. according to some embodiments of the invention, the indium is loaded on the H-Beta molecular sieve support by an ion exchange process.

In a second aspect of the invention, there is provided any one of the CHs provided in the first aspect of the invention₄-a method for preparing an SCR denitration catalyst, comprising the steps of:

s1, uniformly mixing the H-Beta molecular sieve carrier, the metal oxide and the indium-containing ion exchange solution, stirring for reaction at 75-95 ℃, and then carrying out solid-liquid separation;

and S2, washing, drying and grinding the solid obtained by solid-liquid separation in the step S1, and then calcining at 400-550 ℃.

According to some embodiments of the invention, in step S1, the concentration of indium ions in the indium-containing ion-exchange solution is (0.025-0.07) mol/L. Preferably, the concentration of indium ions in the indium-containing ion exchange solution is 0.033 mol/L. In step S1, the stirring reaction time is generally 2 to 10 hours.

According to some embodiments of the invention, the calcination temperature in step S2 is 500 ℃. In step S2, the supernatant is generally washed with water until the supernatant is neutral; after calcination is completed, the mixture is generally tabletted, ground and sieved.

In a third aspect of the present invention, a method for denitration of exhaust gas is provided, wherein selective catalytic reduction is used for treating exhaust gas, and CH is used₄The catalyst is any CH provided by the first aspect of the invention as a reducing agent₄-an SCR denitration catalyst.

The embodiment of the invention has the beneficial effects that:

the embodiment of the invention provides a CH₄-SCR denitration catalyst consisting of Ga₂O₃、Fe₂O₃、NiO、CeO₂With Co₃O₄The metal oxide is mixed with an indium-loaded H-Beta molecular sieve carrier to form the metal oxide; by Ga In comparison to H-Beta molecular sieve supported indium catalysts (i.e., In/H-Beta catalysts)₂O₃、Fe₂O₃、NiO、CeO₂With Co₃O₄The addition of the metal oxide can obviously improve the sulfur resistance and water resistance of the catalyst and improve the denitration rate of the catalyst.

Drawings

FIG. 1 is a schematic view of an evaluation apparatus used in an activity evaluation experiment of a catalyst;

FIG. 2a, FIG. 2b and FIG. 2c show the In/H-Beta catalyst without modification treatment and the In/H-Beta catalyst modified by single metal oxide under the condition of sulfur and water containing_xRemovingRate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 3a, FIG. 3b and FIG. 3c are In-Co₃O₄catalyst/H-Beta and metal oxide modified In-Co₃O₄Catalyst of H-Beta for NO under the condition of containing sulfur and water_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 4a, FIG. 4b and FIG. 4c are In-Fe, respectively₂O₃catalyst/H-Beta and metal oxide modified In-Fe₂O₃Catalyst of H-Beta for NO under the condition of containing sulfur and water_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 5a, FIG. 5b and FIG. 5c are the In-NiO/H-Beta catalyst and the metal oxide modified In-NiO/H-Beta catalyst, respectively, for NO under sulfur-containing aqueous conditions_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 6a, FIG. 6b and FIG. 6c are In-Co₃O₄-Fe₂O₃catalyst/H-Beta and modified In-Co₃O₄-Fe₂O₃Catalyst of H-Beta for NO under the condition of containing sulfur and water_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 7a, FIG. 7b and FIG. 7c are In-Co₃O₄-Ga₂O₃catalyst/H-Beta and modified In-Co₃O₄-Ga₂O₃Catalyst of H-Beta for NO under the condition of containing sulfur and water_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIGS. 8a, 8b and 8c are graphs showing the influence of In ion concentration on NO In the presence of sulfur-containing water In each of the catalysts_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 9a, FIG. 9b and FIG. 9c are graphs showing the effect of mass ratio of metal oxide to molecular sieve on NO in sulfur-containing and water-containing conditions for each of the catalysts_xThe removal rate,CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 10a, FIG. 10b and FIG. 10c are Co₃O₄And Ga₂O₃Influence of mass ratio on NO in the presence of sulfur and water_xRemoval rate, CH₄Conversion and CH₄A graph of selectivity test results;

FIG. 11a, FIG. 11b and FIG. 11c are graphs showing the influence of calcination temperature on NO in the presence of sulfur and water_xRemoval rate, CH₄Conversion and CH₄And (4) a selective test result chart.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.

(one) CH₄Preparation of SCR denitration catalyst

100mL of indium-containing ion exchange solution (indium nitrate) with indium ion concentration of 0.033mol/L is prepared, and then 4g of H-Beta molecular sieve carrier (SiO) is added into the indium-containing ion exchange solution₂/Al₂O₃25) and 1g of metal oxide, uniformly mixing, then placing on a magnetic stirrer, and magnetically stirring for 8 hours in a constant-temperature water bath at the temperature of 85 ℃; then putting the stirred solution on a Buchner funnel, performing suction filtration by using a vacuum pump, and washing with water until the pH value of the lower clear liquid is 7; pouring out the filtrate, taking out the filter cake on the filter paper, putting the filter cake into a drying oven, and drying for 12 hours at the temperature of 80 ℃; and then taking out the dried catalyst, grinding, calcining in a tubular furnace at 500 ℃ for 3h in an air atmosphere, tabletting and grinding the calcined catalyst, and screening by using a 40-60-mesh screen.

By the method, indium ions in indium nitrate in indium ion exchange solution are separatedThe carrier is loaded on the H-Beta molecular sieve by a sub-exchange method and is mixed with metal oxide to form CH₄-SCR denitration catalyst, which can be considered as metal oxide modified In/H-Beta catalyst. Specifically, the single metal oxide modified In/H-Beta catalyst, the double metal oxide modified In/H-Beta catalyst and the triple metal oxide modified In/H-Beta catalyst were prepared according to the above methods, respectively. The metal oxides selected are mainly concentrated in transition metal oxides and group IIIA metal oxides, including Sb₂O₅、La₂O₃、CdO、BiO₂、MoO₃、WO₃、Zr₂O₅、In₂O₃、SnO₂、Ga₂O₃、Ta₂O₅、Co₃O₄、Fe₂O₃、NiO、MnO₂、CeO₂. In addition, CH prepared by the preparation method is not added with metal oxide₄SCR denitration catalyst (In/H-Beta catalyst) as control.

Evaluation of Activity of catalyst

The catalyst activity was evaluated by Temperature Programmed Surface Reaction (TPSR) technique. The evaluation system mainly comprises a gas circuit control system, a catalytic reaction device system and an online analysis and test system, and the schematic diagram of the evaluation device is shown in figure 1.

The experimental process adopts simulated sulfur-containing and water-containing flue gas, the gas is provided by gas steel cylinders, and the gas in each steel cylinder is NO and CH respectively₄、O₂、SO₂And Ar as an equilibrium gas. The water vapor was added by argon bubbling. The gas in the steel cylinder enters the gas circuit control system through a gas pressure reducing valve, and the gas pressure is regulated through a pressure stabilizing valve after the gas is controlled to be switched on and off through a switch valve, so that the gas pressure is 0.1 MPa; and then the flow of each gas path is adjusted through a flow stabilizing valve and a mass flow meter, and different gases enter a gas mixing tube to be uniformly mixed and then enter a reaction tube to react. The inner diameter of the used reaction tube is 6mm, the outer diameter is 10mm, the material is quartz glass tube, quartz cotton is placed in the middle position of the reaction tube to support the catalyst and make the catalyst evenly distributed, the reaction tube is placed in an electric tube resistance furnace,the temperature controller controls the heating rate of the resistance furnace, and the temperature of the catalytic reaction is adjusted by controlling the heating of the resistance furnace by the temperature controller. The on-line analysis test system comprises a nitrogen oxide analyzer (42i) and a gas chromatograph (GC-2014C), and the gas passes through a drying device to remove water in the gas before entering a detection instrument.

The concentrations of the reaction gases of the components in the experiment are as follows: NO 400ppm, CH₄Is 400ppm, O₂At 10 vol%, SO₂100ppm, 5 vol% of water vapor and Ar as an equilibrium gas. The total flow of the gas is 100mL/min, the dosage of the catalyst is 100mg, and the space velocity is 23600h^-1. And introducing the mixed gas into a quartz reaction tube at normal temperature until the catalyst adsorbs and saturates the nitrogen oxide to reach adsorption balance (the number of a nitrogen oxide analyzer is not changed basically). The temperature controller is adjusted to keep the temperature programming rate at 4 ℃/min and the temperature is increased from 100 ℃ to 600 ℃.

Three indexes, namely nitrogen oxide removal rate, methane conversion rate and methane selectivity, are adopted to evaluate the denitration activity of the catalyst. Removal rate of nitrogen oxide with NO_x(de) as shown in formula (1), the higher the removal rate of nitrogen oxide, the higher the NO_xThe higher the (de) value, the higher the denitration activity of the catalyst under the sulfur-containing water condition. In the selective catalytic reduction reaction process, methane is used as the reducing gas of the reaction, the conversion rate of the methane can also directly reflect the activity of the catalyst in the reaction with the methane, so that the activity of the nitrogen oxide catalyst in the reaction with the methane can be indirectly explained, the removal condition of nitrogen oxides, CH, can be indirectly explained₄Conversion of from CH₄(c) Expressed as shown in equation (2). CH (CH)₄The selectivity of (A) can directly reflect the utilization of CH by the catalyst₄Reduction of NO_xAbility of CH₄For NO_xIs selected from CH₄(s) as shown in equation (3).

In the formula, c (NO)_x-in) -Prior to reaction NO_xInitial concentration (ppm);

c(NO_x-out) After reaction NO_xConcentration (ppm);

c(CH_4-in) -Prior to reaction CH₄Initial concentration (ppm);

c(CH_4-out) After reaction CH₄Concentration (ppm).

Sulfur-resistant and water-resistant performance of (III) single metal oxide modified In/H-Beta catalyst

The above single metal oxide (Sb) was subjected to the above activity evaluation method₂O₅、La₂O₃、CdO、BiO₂、MoO₃、WO₃、Zr₂O₅、In₂O₃、SnO₂、Ga₂O₃、Ta₂O₅、Co₃O₄、Fe₂O₃、NiO、MnO₂、CeO₂) The modified In/H-Beta catalyst and the unmodified In/H-Beta catalyst are subjected to activity evaluation to obtain the SO-containing state of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The results of the selectivity test are shown in fig. 2a, fig. 2b and fig. 2c, respectively. Due to the addition of Sb₂O₅、La₂O₃、CdO、BiO₂、MoO₃、WO₃The In/H-Beta catalysts subjected to modification are completely deactivated under sulfur-containing aqueous conditions, and therefore their NO is not shown In FIGS. 2a, 2b and 2c_xRemoval rate, CH₄Conversion and CH₄And (5) selecting a test result.

As can be seen from FIG. 2a, Zr was added₂O₅、In₂O₃、SnO₂The In/H-Beta catalyst to be modified can maintain a certain desorption under the condition of containing sulfur and waterNitro-active, but modified catalyst for NO_xThe removal rate of (b) is reduced to a certain extent compared with that of the In/H-Beta catalyst, therefore, Zr is added₂O₅、In₂O₃、SnO₂The sulfur resistance and water resistance of the In/H-Beta catalyst can not be improved. Adding Ga₂O₃、Ta₂O₅、Co₃O₄、Fe₂O₃、NiO、MnO₂、CeO₂Compared with an In/H-Beta catalyst, the denitration rate of the modified catalyst under the condition of sulfur and water is improved to a certain extent. In-CeO₂The denitration rate of the/H-Beta catalyst is not obviously improved at 600 ℃, but the active temperature window is widened, and when the temperature is higher than 600 ℃, CeO₂The addition of (b) can maintain the denitration rate of the catalyst at its optimum denitration rate. Adding Ta₂O₅The sulfur-resistant and water-resistant performance of the modified In/H-Beta catalyst is improved, and NO is treated at 625 DEG C_xThe removal rate of (3) was 37.2%. In/H-Beta addition of Ga₂O₃、NiO、MnO₂The denitration activity In the whole reaction temperature range under the condition of containing sulfur and water is similar, and the In-Ga is at 625 DEG C₂O₃/H-Beta、In-NiO/H-Beta、In-MnO₂H-Beta vs. NO_xThe removal rates of (a) were 40.7%, 43.1% and 41.9%, respectively; adding Co₃O₄And Fe₂O₃The sulfur-resistant and water-resistant performance of the modified In/H-Beta catalyst is improved most obviously, and the In-Co catalyst is In-Co at 625 DEG C₃O₄/H-Beta、In-Fe₂O₃H-Beta vs. NO_xThe removal rates of (a) and (b) were 65.1% and 55.3%, respectively.

As can be seen from FIG. 2b, the addition of each of the above metal oxides increases the CH content of the catalyst to some extent in both the high-temperature stage and the low-temperature stage₄The conversion rate shows that the addition of the metal oxide can improve the catalyst and CH₄Activity of the reaction. In the low temperature region, In-Ga₂O₃/H-Beta、In-In₂O₃CH of/H-Beta₄The conversion rate is obviously better than that of other catalysts, so that Ga is known to be in a low-temperature region₂O₃And In₂O₃Has a better and CH₄Activity of reactionAnd (4) sex. In the high temperature section, In-Ga₂O₃/H-Beta、In-Ta₂O₅/H-Beta、In-Co₃O₄CH of/H-Beta₄The conversion rate can reach about 90 percent. Bound to NO_xRemoval efficiency to speculate Ta₂O₅Promote CH at high temperature₄The non-selective reaction proceeds, but the denitration reaction is not facilitated.

FIG. 2c shows that In/H-Beta is poor In denitration activity under the condition of containing sulfur and water, and is specific to CH₄Also the conversion of (A) was low, but the In/H-Beta catalyst CH at 550 ℃ and 600 ℃ was low₄The selectivity is much higher than for the modified catalyst. At 550 ℃, In-NiO/H-Beta, In-Fe₂O₃H-Beta and In-Co₃O₄CH of/H-Beta₄Catalyst modified with selectivity superior to other monometal oxide, CH thereof₄The selectivities were 76.2%, 60.9% and 60.2%, respectively. When the temperature rises to 600 ℃, In-NiO/H-Beta, In-Fe₂O₃H-Beta and In-Co₃O₄CH of/H-Beta₄The selectivity is still better than other modified catalysts, In-Fe₂O₃H-Beta and In-Co₃O₄CH of/H-Beta₄The selectivity is closer (54.1 percent and 53.9 percent respectively) and is better than that of the CH of In-NiO/H-Beta₄Selectivity (48.9%). CH of In/H-Beta catalyst at 650 deg.C₄The selectivity is sharply reduced from 77.8% at 600 ℃ to 10.0%. The modified catalyst has better CH at 650 DEG C₄Selectivity of In-Ta₂O₅The temperature at which the/H-Beta has the highest CH₄The selectivity was 58.9%. In-Ga₂O₃/H-Beta、In-In₂O₃CH of/H-Beta₄The selectivities are relatively similar, 56.6% and 56.1%, respectively. And CH at 550 ℃ and 600 ℃₄In-Fe with high selectivity₂O₃/H-Beta、In-Co₃O₄The CH of the/H-Beta and In-NiO/H-Beta increases when the temperature rises to 650 DEG C₄The selectivity dropped to 52.5%, 53.1% and 42.7%, respectively. The rest catalyst also keeps better CH under high temperature condition₄SelectingThe sex can reach more than 40%.

As can be seen from the above, Zr was added₂O₅、In₂O₃、SnO₂The In/H-Beta catalyst is modified to deteriorate the sulfur resistance and water resistance of the In/H-Beta. Addition of metal oxide Ga₂O₃、Ta₂O₅、Co₃O₄、Fe₂O₃、NiO、MnO₂、CeO₂The In/H-Beta catalyst has improved sulfur water resistance, wherein the In-NiO/H-Beta and the In-Fe₂O₃H-Beta and In-Co₃O₄the/H-Beta is either for NO under the condition of containing sulfur and water_xRemoval rate of (2), CH₄Conversion and CH₄The selectivity is obviously better than that of other single metal oxide modified catalysts.

Sulfur-resistant and water-resistant performance of (IV) bimetallic oxide modified In/H-Beta catalyst

Based on the research results of the sulfur resistance and water resistance of the single metal oxide modified In/H-Beta catalyst, three single metal modified In/H-Beta catalyst systems (In-Co) with excellent sulfur resistance and water resistance are further investigated₃O₄/H-Beta、In-Fe₂O₃the/H-Beta and the In-NiO/H-Beta) are respectively oxidized by NiO and Co₃O₄、Fe₂O₃、Ga₂O₃、MnO₂、CeO₂The sulfur-resistant and water-resistant performance of the formed bimetallic oxide modified In/H-Beta catalyst is further modified to carry out research experiments. That is, Co is specifically used₃O₄、Fe₂O₃One of NiO, NiO and Co₃O₄、Fe₂O₃、Ga₂O₃、MnO₂、CeO₂The In/H-Beta catalyst is modified to form the bimetallic oxide modified In/H-Beta catalyst; and then according to the above catalyst activity evaluation method, carrying out research experiment on the sulfur-resistant and water-resistant performances of each bimetallic oxide modified In/H-Beta catalyst, wherein the obtained results comprise:

1. metal oxide modified In-Co₃O₄H-Beta catalystSulfur and water resistance of chemical agent

NiO and Fe were treated by the above method₂O₃、Ga₂O₃、MnO₂、CeO₂Are respectively reacted with Co₃O₄Bimetallic oxide modified In/H-Beta catalyst prepared by combined modification of In/H-Beta and In-Co₃O₄The research experiment of the sulfur-resistant and water-resistant performance of the/H-Beta catalyst is carried out to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The results of the selectivity test are shown in fig. 3a, fig. 3b and fig. 3c, respectively.

As can be seen from FIG. 3a, the metal oxides NiO and Fe₂O₃、Ga₂O₃、MnO₂、CeO₂Can improve In-Co₃O₄Sulfur-and water-resistance of/H-Beta, In which₃O₄-Fe₂O₃/H-Beta、In-Co₃O₄-Ga₂O₃The denitration activity of the/H-Beta is highest under the condition of containing sulfur and water, and the denitration activity is to NO at 625 DEG C_xThe removal rates were 71.5% and 74.6%, respectively. Adding NiO and CeO₂Compared with Co-doped catalyst, the sulfur-resistant and water-resistant performance of the catalyst modified by doping is improved₃O₄、Ga₂O₃Weaker, NO at 625 ℃_xThe removal rates of (a) and (b) were 68.9% and 69.7%, respectively. And In-Co₃O₄-MnO₂The denitration activity of the/H-Beta is basically not obviously changed from the activity before the modification in the whole temperature range, which shows that MnO is not obviously changed₂Addition of (2) does not improve In-Co₃O₄The sulfur resistance and water resistance of the/H-Beta catalyst.

As can be seen from FIG. 3b, CH₄Trend of conversion with NO_xThe trend of the removal rate was almost the same. The addition of the above metal oxide can further improve the catalyst and CH₄The reactivity of (A) is CH of the modified catalyst in both the low temperature stage and the high temperature stage₄The conversion rate is improved.

From FIG. 3c, the CH of the catalyst₄Selectivity with increasing temperatureDecrease of In-Co over a temperature range of 550 ℃ to 600 DEG C₃O₄-NiO/H-Beta、In-Co₃O₄-Fe₂O₃/H-Beta、In-Co₃O₄-Ga₂O₃CH of/H-Beta₄The selectivity is relatively close and is obviously superior to CH of other catalysts at the same temperature₄And (4) selectivity. In-Co at 650 deg.C₃O₄-Fe₂O₃CH of/H-Beta₄The selectivity was the highest, 40.3%.

2. Metal oxide modified In-Fe₂O₃Sulfur-resistant and water-resistant performance of/H-Beta catalyst

NiO and Co are treated by the above method₃O₄、Ga₂O₃、MnO₂、CeO₂Are each independently of Fe₂O₃Bimetallic oxide modified In/H-Beta catalyst prepared by combined modification of In/H-Beta and In-Fe₂O₃The research experiment of the sulfur-resistant and water-resistant performance of the/H-Beta catalyst is carried out to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 4a, 4b and 4c, respectively.

As can be seen from FIGS. 4a to 4c, Co is added₃O₄In-Fe of₂O₃The sulfur resistance and water resistance of the/H-Beta are improved, and the resistance to NO is improved at 625 DEG C_xThe removal rate of (a) was 61.8%; while the addition of other metal oxides reduces In-Fe₂O₃The sulfur-resistant and water-resistant performance of the/H-Beta is especially doped with NiO and Ga₂O₃Catalyst NO of_xThe removal rate of the CeO-doped CeO-alloy is reduced to 45.1 percent and 45.8 percent from 55.3 percent₂、MnO₂The sulfur resistance and water resistance of the modified catalyst are similar, and the modified catalyst is used for NO at 625 DEG C_xThe removal rates of (a) and (b) were 48.8% and 49.6%, respectively. For CH₄Conversion rate except for In-Fe₂O₃-CeO₂The H-Beta is for CH over the entire temperature range₄In addition to not increasing the conversion, the addition of the remaining metal oxide increases the CH₄And (4) conversion rate.For CH₄Selectivity, Co₃O₄The addition of (A) improves the selectivity of the catalyst in the whole active temperature range, and CeO₂The addition of (2) increases the CH of the catalyst at 550 ℃₄Selectivity, the selectivity at this point was 65.1%. The addition of other metal oxides does not improve In-Fe₂O₃CH of/H-Beta₄And (4) selectivity.

3. Sulfur-resistant and water-resistant performance of metal oxide modified In-NiO/H-Beta catalyst

For Fe by the above method₂O₃、Co₃O₄、Ga₂O₃、MnO₂、CeO₂The bimetallic oxide modified In/H-Beta catalyst prepared by modifying In/H-Beta respectively by combining with NiO and the In-NiO/H-Beta catalyst are subjected to sulfur-resistant and water-resistant performance research experiments to obtain the catalyst containing SO₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 5a, fig. 5b and fig. 5c, respectively.

As can be seen from FIGS. 5a to 5c, Co is selected₃O₄、Ga₂O₃The sulfur-resistant and water-resistant performance of the catalyst subjected to doping modification is improved, wherein Co is added₃O₄The sulfur resistance and water resistance of the modified catalyst are improved most, and NO is treated at 625 DEG C_xThe removal rate of (b) was 65.3%, In-NiO-Ga₂O₃H-Beta vs. NO_xThe removal rate of (3) was 49.6%. To be doped with CeO₂、Fe₂O₃And MnO₂The sulfur-resistant and water-resistant properties of the catalyst may be decreased, wherein the modified catalyst having the worst sulfur-resistant and water-resistant properties is In-NiO-Fe₂O₃The NOx removal rate at 625 ℃ was 38.2%. The CH can be improved by adding metal oxide to modify an In-NiO/H-Beta system₄Conversion, modified catalyst CH₄Trend of conversion with NO_xThe change trend of the removal rate is basically consistent.

To sum up, In-Co₃O₄/H-Beta、In-Fe₂O₃Based on the/H-Beta and In-NiO/H-Beta systemsThe one-step modification is found In-Co₃O₄The modification effect is obviously better than that of other two systems on the basis of the/H-Beta system, wherein In-Co₃O₄-Fe₂O₃/H-Beta、In-Co₃O₄-Ga₂O₃The sulfur resistance and water resistance of the/H-Beta are obviously better than those of other catalysts. At 625 deg.C, for NO_xThe removal rates of (a) and (b) were 71.5% and 74.6%, respectively, In-Co₃O₄H-Beta vs NO_xThe removal rate is obviously improved; to CH₄The conversion of (A) was 73.2% and 75.8%, respectively, for CH₄The selectivity of the catalyst is respectively 50.2 percent and 48.8 percent, and is obviously improved compared with a single metal oxide modified system.

Sulfur-resistant and water-resistant performance of (V) trimetal oxide modified In/H-Beta catalyst

Based on the research results of the sulfur resistance and water resistance of the bimetallic oxide modified In/H-Beta catalyst, two bimetallic modified In/H-Beta catalyst systems (In-Co) with better sulfur resistance and water resistance are further investigated₃O₄-Fe₂O₃H-Beta and In-Co₃O₄-Ga₂O₃/H-Beta) is respectively processed by NiO and Fe₂O₃、Ga₂O₃、MnO₂、CeO₂The sulfur-resistant and water-resistant performance of the formed bimetallic oxide modified In/H-Beta catalyst is further modified to carry out research experiments. That is, NiO and Fe are used specifically₂O₃、Ga₂O₃、MnO₂、CeO₂And (Co)₃O₄+Fe₂O₃) Or (Co)₃O₄+Ga₂O₃) Combining to form metal oxide, and modifying the In/H-Beta catalyst to form a tri-metal oxide modified In/H-Beta catalyst; and then according to the above catalyst activity evaluation method, carrying out research experiment on the sulfur-resistant and water-resistant performances of each trimetal oxide modified In/H-Beta catalyst, wherein the obtained results comprise:

1. modified In-Co₃O₄-Fe₂O₃Sulfur-resistant and water-resistant performance of/H-Beta catalyst

NiO is treated by the method,Ga₂O₃、MnO₂、CeO₂Are respectively reacted with (Co)₃O₄+Fe₂O₃) Tri-metal oxide modified In/H-Beta catalyst prepared by combined modification of In/H-Beta and In-Co₃O₄-Fe₂O₃The research experiment of the sulfur-resistant and water-resistant performance of the/H-Beta catalyst is carried out to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 6a, fig. 6b and fig. 6c, respectively.

As is clear from FIGS. 6a and 6b, Ga is added₂O₃In-Co of₃O₄-Fe₂O₃The sulfur resistance and water resistance of the/H-Beta are improved to a certain extent, and the performance on NO is improved at 625 DEG C_xThe removal rate of the catalyst can reach 76.9 percent compared with In-Co₃O₄-Fe₂O₃The improvement of the/H-Beta is 3.5 percent. In-Co₃O₄-Fe₂O₃-Ga₂O₃the/H-Beta is to CH in both the low temperature section and the high temperature section₄The conversion rate is improved, and CH is obtained when the temperature reaches 650 DEG C₄The highest conversion rate can reach 91.6 percent. Adding CeO₂In-Co of₃O₄-Fe₂O₃The sulfur resistance and water resistance of the/H-Beta are compared with those of In-Co In a low temperature region₃O₄-Fe₂O₃the/H-Beta is greatly improved, but In a high-temperature region, the denitration activity of the catalyst is combined with that of In-Co₃O₄-Fe₂O₃The denitration activity of the/H-Beta is basically the same. And for CH₄In terms of conversion, In-Co is present In both the low temperature stage and the high temperature stage₃O₄-Fe₂O₃-CeO₂CH of/H-Beta₄Trend of conversion and In-Co₃O₄-Fe₂O₃the/H-Beta is almost the same. In-Co₃O₄-Fe₂O₃-MnO₂the/H-Beta catalyst is used for NO in a low-temperature region_xThe removal rate of the catalyst is better than that of other catalysts, the high activity of other catalysts can not be achieved in a high-temperature section, and NO is not removed at 625 DEG C_xThe removal rate was 66.8%.In-Co over the whole temperature range₃O₄-Fe₂O₃-MnO₂CH of/H-Beta₄The conversion rate is higher than that of In-Co₃O₄-Fe₂O₃/H-Beta。

As can be seen from FIG. 6c, CeO was added at 550 deg.C₂NiO and MnO₂Catalyst modified relative to unmodified pre-CH₄The selectivity is improved, wherein In-Co₃O₄-Fe₂O₃CH of-NiO/H-Beta₄The selectivity was the highest, 92.9%. CH of each catalyst at a temperature of 600 deg.C₄The selectivities are very close. When the temperature reaches 650 ℃, In-Co₃O₄-Fe₂O₃-Ga₂O₃CH of/H-Beta₄The selectivity was highest at 41.4%. It can be seen that In-Co is present throughout the active temperature range₃O₄-Fe₂O₃-Ga₂O₃the/H-Beta can always keep higher CH₄And (4) selectivity.

2. Modified In-Co₃O₄-Ga₂O₃Sulfur-resistant and water-resistant performance of/H-Beta catalyst

NiO and Fe were treated by the above method₂O₃、MnO₂、CeO₂Are respectively reacted with (Co)₃O₄+Ga₂O₃) Tri-metal oxide modified In/H-Beta catalyst prepared by combined modification of In/H-Beta and In-Co₃O₄-Ga₂O₃The research experiment of the sulfur-resistant and water-resistant performance of the/H-Beta catalyst is carried out to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 7a, fig. 7b and fig. 7c, respectively.

As can be seen from FIGS. 7a to 7c, In-Co₃O₄-Ga₂O₃After other metal oxides are added into the/H-Beta system for modification, the sulfur resistance and the water resistance are not improved, but are reduced. CH of all catalysts modified with trimetallic oxide₄The conversion rate of (A) is in both the high temperature range and the low temperature rangeAnd (5) reducing. CH for catalyst₄Optionally, adding Fe₂O₃NiO and CeO₂The catalyst to be modified has CH at 550 ℃₄The selectivity was improved, but as the temperature continued to rise, the modified catalyst was compared to the CH before modification₄The selectivity is reduced.

To sum up, In-Co₃O₄-Fe₂O₃H-Beta and In-Co₃O₄-Ga₂O₃Further metal oxide modification is carried out on the basis of the catalytic system of the/H-Beta. The experimental result shows that the sulfur-resistant and water-resistant performance of the catalyst is not improved along with the increase of the types of metal oxides, most of the further modified catalysts have slightly reduced sulfur-resistant and water-resistant performance compared with the original catalytic system, and only In-Co₃O₄-Fe₂O₃The sulfur resistance and water resistance of the catalyst/H-Beta are slightly improved, and NO is generated at 625 DEG C_xThe removal rate is improved from the original 74.6 percent to 76.9 percent.

(VI) Experimental study on influence of preparation conditions on sulfur resistance and water resistance of catalyst

Although the sulfur resistance and water resistance of the catalyst modified by adding the three metal oxides are superior to those of the catalyst modified by the double metal oxides, the sulfur resistance and water resistance are not obviously improved, and the catalyst system is more complicated by adding the three metal oxides, so that the In-Co is selected₃O₄-Ga₂O₃The H-Beta is further subjected to an experiment on the influence of the preparation conditions on the sulfur-resistant and water-resistant performances of the catalyst.

In CH₄In SCR, the preparation conditions directly influence the denitration activity of the catalyst, and the conditions that can be controlled and influence the activity of the catalyst in the ion exchange process include: ion exchange solution concentration, ion exchange time, ion exchange temperature and calcination temperature. The preparation conditions studied in the present invention include: in ion exchange solution, mass ratio of metal oxide to molecular sieve, and Co₃O₄And Ga₂O₃Mass ratio and calcination temperature. The specific methods and results are as follows:

1. experimental study on influence of In ion concentration

CH was prepared according to the preparation method of the first paragraph using ion-exchange solutions containing no In ion and having In ion concentrations of 0.01M (i.e., 0.01mol/L), 0.02M, 0.033M, 0.05M and 0.066M, respectively₄-an SCR denitration catalyst. Other preparation conditions were as follows: the mass ratio of the metal oxide to the carrier is 1: 4, Co₃O₄And Ga₂O₃The mass ratio of (A) to (B) is 4: 1, the calcination temperature is 500 ℃. Then, the denitration activity evaluation is carried out on each catalyst according to the activity evaluation method of the catalyst described in the second part to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄Results of the selectivity test are shown in fig. 8a, 8b and 8 c.

As can be seen from FIG. 8a, if In is not added during the preparation of the catalyst, the catalyst will not have denitration activity under the sulfur-containing aqueous condition, demonstrating that In is present throughout CH₄-important denitration active components in SCR reactions. As the In ion concentration increases, the optimum denitration activity of the catalyst tends to increase and then decrease. Catalyst vs NO at 625 ℃ when In ion concentration is 0.01M_xThe removal rate of (2) was only 29.8%. When the In ion concentration was increased to 0.02M, the low temperature activity of the catalyst also showed a tendency to increase for NO_xThe removal rate of the catalyst can reach 41.1 percent at most, when the concentration of In ions is 0.033M, the denitration activity of the prepared catalyst is highest, and when the temperature is 625 ℃, NO is generated_xThe removal rate of (2) was 74.6%. As the In ion concentration continues to increase, In-Co₃O₄-Ga₂O₃H-Beta vs. NO_xThe maximum removal rate of (2) is also decreased, and NO is observed at In concentrations of 0.05M and 0.066M_xThe maximum removal rates were 65.7% and 64.5%, respectively. It is noted that when the In ion concentration is 0.05M, the low-temperature denitration activity of the catalyst under the sulfur-containing and water-containing condition is obviously improved, the optimal activity temperature is 600 ℃, and the denitration activity of the catalyst prepared under the temperature of 550 ℃ is optimal compared with that of the catalyst prepared under other conditions.

FIG. 8b shows that the catalyst produced at different In ion concentrations is paired with CH₄All increases with increasing temperature and the CH between different catalysts₄Law of change of conversion and its response to NO_xThe conversion of (A) is substantially in accordance with the law that the catalyst is on NO_xThe higher the removal rate of (A), its CH₄The higher the conversion.

As can be seen from FIG. 8c, the catalyst without In had no denitration activity and thus it was able to react with CH₄The selectivity of (a) is also almost zero. The remaining catalyst pairs CH₄The change law of the selectivity is increased and then reduced along with the temperature rise. In the high-temperature stage, CH of catalyst₄The selectivity shows a decreasing trend with increasing temperature. In ion concentrations of 0.05M and 0.066M at 550 ℃ for the CH of the catalyst prepared₄The selectivity is obviously higher than that of other catalysts, and the selectivity is 98.4 percent and 97.3 percent respectively. CH of the catalyst at an In ion concentration of 0.05M when the temperature was raised to 600 deg.C₄The highest selectivity, about 72.5%, In ion concentrations of 0.033M and 0.066M gave a catalyst with CH₄Selectivity was comparable, 57.2% and 56.2%, respectively, with an In ion concentration of 0.01M CH₄The selectivity was the worst, only 35.4%. At a temperature of 650 ℃ CH₄In-Co with high selectivity of 0.033M, 0.066M, 0.05M, 0.02M and 0.01M, and In ion concentration of 0.033M₃O₄-Ga₂O₃the/H-Beta shows good CH under high temperature condition₄And (4) selectivity. According to the experimental result, the catalysts prepared by high In ion concentration all have higher CH₄Alternatively, an increase In the In ion concentration may limit CH₄Carrying out non-selective oxidation reaction.

2. Experimental study on influence of mass ratio of metal oxide to molecular sieve

Respectively adopting the mass ratio of metal oxide to molecular sieve as 2: 40. 5: 40. 10: 40. 20: 40 and 40: 40 according to the preparation process described in the first paragraph. Other preparation conditions were as follows: in ion concentration 0.033M, Co₃O₄And Ga₂O₃4: 1, the calcining temperature is 500 ℃. The activity of the catalyst was then assessed according to the second sectionCarrying out denitration activity evaluation on each catalyst by a valence method to obtain SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 9a, 9b and 9 c.

As can be seen from FIG. 9a, as the mass ratio of metal oxide to molecular sieve increases, In-Co₃O₄-Ga₂O₃H-Beta on NO under Sulfur-containing aqueous conditions_xThe maximum removal rate of (a) is increased and then decreased, wherein the optimal mass ratio is 10: 40 at 625 ℃ to NO_xThe removal rate of the catalyst can reach 74.6 percent; for NO_xThe lowest removal rate equivalent mass ratio is 40: 40, only 29.6% at 625 ℃.

From FIG. 9b, the CH of the catalyst₄Change in conversion with NO_xThe change in conversion rate coincides with CH over the entire temperature range₄The conversion increases and then decreases with increasing mass ratio.

From FIG. 9c, it can be seen that CH of each catalyst₄The selectivity decreases with increasing temperature, and the mass ratio of 2: 40 exhibited good CH at 550 deg.C₄The selectivity, in this case 94.5%. CH at 600 ℃ and 650 ℃₄The mass ratio of the highest selectivity is 10: 40, CH₄The selectivity was 57.2% and 37.3%, respectively.

In summary, when the mass ratio of the metal oxide to the molecular sieve is 10: at 40 f, the catalyst has the best denitration activity under the sulfur-containing and water-containing conditions, and the catalyst prepared at the mass ratio has CH₄The conversion rate is higher than that of other catalysts, and the mass ratio of proper metal oxide to molecular sieve can properly improve CH₄Selectivity, the mass ratio at the optimum activation temperature is 10: CH of catalyst at 40-₄The selectivity is the highest.

3、Co₃O₄And Ga₂O₃Experimental study on the influence of mass ratio

Respectively using Co₃O₄And Ga₂O₃The mass ratio is 1: 1. 2: 1. 3: 1. 4: 1 and 5: 1 according to the first partPreparation method for preparing In-Co₃O₄-Ga₂O₃a/H-Beta catalyst. Other preparation conditions were as follows: the In ion concentration is 0.033M, and the mass ratio of the metal oxide to the molecular sieve is 4: 1, the calcination temperature is 500 ℃. Then, the denitration activity evaluation is carried out on each catalyst according to the activity evaluation method of the catalyst described in the second part to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The results of the selectivity tests are shown in fig. 10a, 10b and 10 c.

As can be seen from FIG. 10a, with Co₃O₄And Ga₂O₃Is prepared from 1: 1 liter to 4: 1, In-Co₃O₄-Ga₂O₃H-Beta vs. NO_xThe maximum removal rate of (2) is increased, and at 625 deg.C, for NO_xThe removal rate of (a) increased from 63.4% to 74.6%, but as the mass ratio continued to increase to 5: 1, In-Co₃O₄-Ga₂O₃H-Beta vs. NO_xThe removal rate of (2) is greatly reduced, and NO is removed at 625 DEG C_xThe removal rate of (A) was only 39.1%.

As can be seen from FIGS. 10b and 10c, the results of the experiments show that different Co conversions can be obtained for CH4₃O₄And Ga₂O₃CH of catalyst prepared at mass ratio₄Trend of conversion and for NO_xThe removal rate variation trend of (A) is basically consistent, and CH is distributed in the whole temperature range₄Highest conversion and NO_xThe mass ratio of the highest removal rate is 4: 1, and CH₄Lowest conversion and NO_xThe mass ratio of the lowest removal rate is 5: 1. for CH₄Selectivity, CH of each catalyst₄The selectivity decreases with increasing temperature. Although Co is present₃O₄And Ga₂O₃The mass ratio is 4: 1 hour to NO_xHas a high removal rate, but is directed to CH over the entire temperature range₄Has a very low selectivity, and it has been found that the catalyst prepared at this mass ratio promotes CH₄Non-selective oxidation reaction of (2). At 550 ℃, Co₃O₄And Ga₂O₃The mass ratio is 1: catalyst prepared at 1 has maximum CH₄Selectivity of 91.8%, Co at 600 deg.C₃O₄And Ga₂O₃The mass ratio is 3: 1 catalyst has the highest CH₄The selectivity was 65.7%. When the temperature continued to rise to 650 ℃, except for a mass ratio of 5: 1 catalyst, CH of catalyst prepared at each mass ratio₄The selectivity is comparable. 4. Experimental study on influence of calcination temperature

Preparing In-Co according to the preparation method In the first part at the calcining temperature of 400 ℃, 450 ℃, 500 ℃, 550 ℃ and 600 ℃ respectively₃O₄-Ga₂O₃a/H-Beta catalyst. Other preparation conditions were as follows: the In ion concentration is 0.033M, and the mass ratio of the metal oxide to the molecular sieve is 4: 1, Co₃O₄And Ga₂O₃The mass ratio of (A) to (B) is 4: 1. then, the denitration activity evaluation is carried out on each catalyst according to the activity evaluation method of the catalyst described in the second part to obtain the SO content of each catalyst₂And H₂Nitrogen Oxide (NO) in O gas atmosphere_x) Removal rate, CH₄Conversion and CH₄The selectivity test results are shown in fig. 11a, 11b and 11 c.

As can be seen from FIG. 11a, the catalyst is used for NO under the condition of sulfur and water_xThe removal rate of (a) is increased and then decreased with the increase of the calcination temperature, wherein the calcination temperature is 500 ℃ to prepare In-Co₃O₄-Ga₂O₃The best denitration activity of/H-Beta is NO at 625 DEG C_xThe removal rate is the highest and can reach 74.6 percent. And the catalyst prepared by selecting the calcination temperature of 600 ℃ has NO reaction in the whole temperature range_xThe removal of (a) is inactive, presumably because the metal oxide is sintered on the surface of the molecular sieve due to the too high firing temperature, and active sites on the surface of the catalyst are damaged; on the other hand, too high a temperature may cause collapse of the framework of the molecular sieve, which in turn may lead to deactivation of the catalyst.

As can be seen from FIGS. 11b and 11c, catalyst CH₄The conversion rate varies over the temperature rangePotential and NO_xThe change trend of the removal rate is basically consistent, namely the catalyst is used for NO_xThe higher the removal rate of (A), its CH₄The higher the conversion. For CH₄Selectivity, CH of catalyst₄The selectivity decreases with increasing temperature and the calcination temperature of the catalyst is relative to CH₄The selectivity impact is small. Since the catalyst prepared at 600 ℃ is almost inactive under sulfur-containing aqueous conditions, its CH₄Selectivity is not of practical reference value. The catalyst prepared at a calcination temperature of 400 ℃ at 550 ℃ exhibited the highest CH₄The selectivity, in this case, was 70.1%. Catalyst prepared under various conditions at 600 ℃ for CH₄The selectivities were almost identical, and when the temperature rose to 650 ℃, the CH of the catalyst₄The selectivity is greatly reduced, and the catalyst prepared at the calcining temperature of 500 ℃ shows high CH compared with other catalysts₄Selectivity, in this case CH₄The selectivity was 37.3%.

In conclusion, the catalyst prepared at the calcination temperature of 500 ℃ has higher NO under the condition of sulfur and water_xRemoval rate and CH₄Conversion while on CH in the high temperature range₄The selectivity is also superior.

Claims

1. CH (physical channel)₄-SCR denitration catalyst, characterized in that the CH₄-the components of the SCR denitration catalyst comprise an H-Beta molecular sieve support, indium and a metal oxide, the indium being supported on the H-Beta molecular sieve support;

2. The CH of claim 1₄-SCR denitration catalyst, characterized in that said metal oxide is selected from Ga₂O₃、Fe₂O₃With Co₃O₄Combinations of (a) and (b).

3. The CH of claim 2₄-SCR denitration catalyst, characterized in that said metal oxide is selected from Ga₂O₃And Co₃O₄Combinations of (a) and (b).

4. The CH of claim 2₄-an SCR denitration catalyst, characterized in that the metal oxide is selected from the group consisting of (1-4) by mass: 1 Co₃O₄And Ga₂O₃。

5. The CH of any one of claims 1-4₄-an SCR denitration catalyst, characterized in that the mass ratio of said metal oxide to said H-Beta molecular sieve support is 1: (2-8).

6. The CH of any one of claims 1-4₄-SCR denitration catalyst, characterized in that said indium accounts for said CH₄The mass percentage of the-SCR denitration catalyst is 2-7 wt%.

7. The CH of any one of claims 1-4₄-an SCR denitration catalyst, characterized in that said indium is supported on said H-Beta molecular sieve support by an ion exchange process.

8. CH according to any one of claims 1 to 7₄-a method for preparing an SCR denitration catalyst, characterized by comprising the steps of:

9. The CH of claim 8₄A method for producing an SCR denitration catalyst, characterized in that in step S1, indium ions are separated from the indium-containing ion exchange liquidThe concentration of the seed is (0.025-0.07) mol/L.

10. The method for denitration of waste gas is characterized in that the waste gas is treated by a selective catalytic reduction method, and CH is used₄The catalyst is the CH as defined in any one of claims 1 to 7 as a reducing agent₄-an SCR denitration catalyst.