Metal salt catalyst for desulfurization and denitrification as well as preparation method and application of metal salt catalyst

Abstract

The invention relates to the field of chemical industry production, and discloses a metal salt catalyst for desulfurization and denitrification and a preparation method and application thereof.The metal salt catalyst comprises 30%-35% of an active metal component, 60%-65% of a carrier and 5%-10% of an auxiliary, the active metal component is specifically ferrous sulfate, and through the activity of ferric salt at medium and low temperatures, the metal salt can be used as a catalyst for desulfurization and denitrification. The surface acidity of the catalyst is adjusted by the alkali metal sodium and the rare earth element cerium, the active temperature range is widened, the carrier is aluminum oxide specifically, the auxiliary agent is composed of the alkali metal sodium accounting for 3-6% of the total mass and the rare earth element cerium accounting for 2-4% of the total mass, and meanwhile the alkali metal sodium and the rare earth element cerium can reduce impurity adsorption and improve the catalytic activity of the catalyst. The anti-poisoning capability is enhanced. The active temperature range of the catalyst is widened by reasonably selecting the active metal components, the carrier and the auxiliaries, so that the catalyst can adapt to flue gas temperature changes under different working conditions, and a wider application scene is provided for desulfurization and denitrification in industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, in particular to a metal salt catalyst for desulfurization and denitration and a preparation method and application thereof. Background Art

[0002] With the continuous expansion of industrial production, especially the rapid development of chemical, steel, electricity and other fields, the massive consumption of energy has brought about serious air pollution problems. Among them, the emission of sulfur oxides and nitrogen oxides has become one of the main causes of air pollution, causing great harm to human health and the ecological environment. In order to meet this challenge and achieve sustainable development, efficient desulfurization and denitrification technology has become an urgent need in industrial production.

[0003] The currently widely used desulfurization and denitrification technologies have many shortcomings. On the one hand, many traditional catalysts have a narrow active temperature range and cannot adapt to changes in flue gas temperature under different operating conditions. For example, some catalysts are only effective at high temperatures, and their activity is greatly reduced at medium and low temperatures. On the other hand, the anti-poisoning ability is insufficient, and impurities in the flue gas, such as dust and heavy metals, can easily poison the catalyst and reduce its catalytic performance. At the same time, the stability of existing catalysts is poor, the active components are easily lost or sintered, and the thermal stability and mechanical strength of the carrier are difficult to meet the requirements of long-term use. In addition, the selectivity for specific pollutants is low, and key pollutants in complex flue gases cannot be efficiently removed. Moreover, some existing catalysts are relatively expensive, which limits their large-scale application.

[0004] In view of the various problems of existing technologies, it is imperative to develop efficient and low-cost metal salt catalysts for desulfurization and denitrification. By rationally selecting active metal components, carriers and additives, and optimizing the preparation method, the active temperature range of the catalyst can be broadened, the anti-poisoning ability can be enhanced, the stability and selectivity for specific pollutants can be improved, and the cost can be reduced. This not only helps to meet increasingly stringent environmental standards, but also provides a new solution for the sustainable development of industrial production. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a metal salt catalyst for desulfurization and denitrification and a preparation method and application thereof, which solves the problems in the existing desulfurization and denitrification technologies that the catalysts have a narrow active temperature range, insufficient anti-poisoning ability, poor stability, low selectivity for specific pollutants, and cannot meet the requirements of industrial production.

[0006] To achieve the above objectives, the present invention is implemented through the following technical scheme: the metal salt catalyst for desulfurization and denitrification includes active metal components: 30%-35%, carrier: 60%-65%, and auxiliary agent: 5%-10%.

[0007] Preferably, the active metal component is ferrous sulfate.

[0008] Preferably, the carrier is alumina.

[0009] Preferably, the auxiliary agent is specifically composed of 3-6% of alkali metal sodium and 2%-4% of rare earth element cerium in terms of the total mass.

[0010] The preparation method of the metal salt catalyst for desulfurization and denitrification comprises the following steps:

[0011] S1. Raw material preparation: preparing active metal salts, carriers and additives, and pretreating the active metal salts, carriers and additives;

[0012] S2. Preparation by impregnation method: dissolve the active metal salt in an appropriate solvent, wherein the appropriate solvent includes deionized water and ethanol, to form an impregnation solution; and immerse the pretreated carrier in the impregnation solution to adsorb the active metal salt on the surface of the carrier. Stirring, ultrasound and other methods can be used to promote the impregnation process and improve the impregnation effect. The impregnation time is 5 hours to 10 hours; take out the impregnated carrier, dry it at a certain temperature to remove the solvent. The drying temperature is usually between 80°C and 150°C; the dried catalyst is calcined at a certain temperature to convert the active metal salt into an active catalyst. The calcination temperature is determined according to the properties of the active metal salt and the performance requirements of the catalyst, and is generally between 300°C and 800°C. The calcination time is generally 5 hours to 10 hours;

[0013] S3. Post-treatment: Grind the calcined catalyst to meet certain particle size requirements. Then remove oversized or undersized particles through screening to ensure the uniformity of the catalyst particle size; activate the catalyst by introducing reducing gas at a temperature of 200°C to 500°C to reduce the active metal ions on the catalyst surface to an active state;

[0014] S4. Packaging and storage: Use cans or sealed bags to properly package the activated metal salt catalysts for desulfurization and denitrification to ensure that the performance of the catalyst is not affected during storage and transportation.

[0015] Preferably, the pretreatment of the active metal salt in step S1 specifically comprises: grinding the metal salt to meet the particle size requirement to increase the reaction activity and uniformity.

[0016] Preferably, the pretreatment of the carrier in step S1 specifically includes: pretreatment of the carrier to remove impurities and increase the specific surface area and porosity of the carrier, wherein the specific pretreatment methods include washing, drying and calcining.

[0017] Preferably, the pretreatment of the auxiliary agent in step S1 specifically comprises: grinding or dissolving the auxiliary agent so that it can be evenly dispersed in the catalyst system.

[0018] Preferably, the reducing gas in step S3 is specifically: the reducing gas includes hydrogen and carbon monoxide.

[0019] The application of the metal salt catalyst for desulfurization and denitrification, as described in any one of claims 1-2, is applied in the field of industrial production, especially in the field of environmental protection and the field of energy.

[0020] The present invention provides a metal salt catalyst for desulfurization and denitration and a preparation method and application thereof.

[0021] Beneficial effects:

[0022] 1. The present invention broadens the active temperature range of the catalyst by rationally selecting active metal components, carriers and additives, so that it can adapt to the changes in flue gas temperature under different working conditions, and provides a wider range of application scenarios for desulfurization and denitrification in industrial production.

[0023] 2. The present invention utilizes alkali metals and rare earth elements in the additives to reduce impurity adsorption and form stable compounds with impurities, which significantly enhances the anti-poisoning ability of the catalyst. At the same time, under the influence of complex impurities in actual industrial flue gas, it can still maintain stable performance, reduce maintenance costs and replacement frequency, and improve the efficiency and sustainability of industrial production.

[0024] 3. The present invention greatly improves the stability of the catalyst by selecting a carrier with high thermal stability and mechanical strength, and combining the pretreatment and post-treatment steps in the preparation process. This not only ensures the stable performance of the catalyst during long-term use, but also extends its service life, providing reliable guarantee for the stable operation of industrial production.

[0025] 4. The combination of different active metal components and carriers of the present invention endows the catalyst with higher selectivity for specific pollutants. In a complex flue gas environment, it can more effectively remove key pollutants, improve the overall desulfurization and denitrification effects, and meet increasingly stringent environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1:

[0029] Please see attached Figure 1 The embodiment of the present invention provides a metal salt catalyst for desulfurization and denitrification, including an active metal component: 30%, a carrier: 65%, and an auxiliary agent: 5%, wherein the active metal component is specifically ferrous sulfate; the carrier is specifically alumina, and the auxiliary agent is specifically composed of 3% alkali metal sodium and 2% rare earth element cerium of the total mass.

[0030] The preparation method of the metal salt catalyst for desulfurization and denitrification comprises the following steps:

[0031] S1. Raw material preparation: prepare active metal salts, carriers and additives;

[0032] Grinding the metal salt to meet the particle size requirements to increase reactivity and uniformity;

[0033] At the same time, the carrier is pretreated to remove impurities and increase the specific surface area and porosity of the carrier, wherein the specific pretreatment methods include washing, drying and calcining;

[0034] and grinding or dissolving the additive so that it can be evenly dispersed in the catalyst system;

[0035] S2. Preparation by impregnation method: dissolve the active metal salt in an appropriate solvent, wherein the appropriate solvent includes deionized water and ethanol, to form an impregnation solution; and immerse the pretreated carrier in the impregnation solution to adsorb the active metal salt on the surface of the carrier. Stirring, ultrasound and other methods can be used to promote the impregnation process and improve the impregnation effect. The impregnation time is 5 hours to 10 hours; take out the impregnated carrier, dry it at a certain temperature to remove the solvent. The drying temperature is usually between 80°C and 150°C; the dried catalyst is calcined at a certain temperature to convert the active metal salt into an active catalyst. The calcination temperature is determined according to the properties of the active metal salt and the performance requirements of the catalyst, and is generally between 300°C and 800°C. The calcination time is generally 5 hours to 10 hours;

[0036] S3. Post-treatment: Grind the calcined catalyst to meet certain particle size requirements. Then remove oversized or undersized particles through screening to ensure the uniformity of the catalyst particle size; activate the catalyst by introducing a reducing gas at a temperature of 200°C to 500°C, wherein the reducing gas includes hydrogen and carbon monoxide, to reduce the active metal ions on the catalyst surface to an active state;

[0037] S4. Packaging and storage: Use cans or sealed bags to properly package the activated metal salt catalysts for desulfurization and denitrification to ensure that the performance of the catalyst is not affected during storage and transportation.

[0038] The application of the metal salt catalyst for desulfurization and denitrification, as described in any one of claims 1-2, is applied in the field of industrial production, especially in the field of environmental protection and the field of energy.

[0039] Embodiment 1 Beneficial effects: This catalyst broadens the active temperature range by combining the activity of iron salt at medium and low temperatures with the regulation of the surface acidity of the catalyst by alkali metal sodium and rare earth element cerium. At the same time, alkali metal sodium and rare earth element cerium can reduce the adsorption of impurities and enhance the anti-poisoning ability. The high thermal stability and mechanical strength of the alumina carrier improve the stability of the catalyst. The metal salt catalyst for desulfurization and denitrification of this component has greater advantages in the medium and low temperature range and is relatively cheaper.

[0040] Embodiment 2: A metal salt catalyst for desulfurization and denitrification comprises an active metal component: 40%, a carrier: 50%, and an auxiliary agent: 5%, wherein the active metal component is specifically a copper salt (copper sulfate) and a manganese salt (manganese sulfate) mixed in a ratio of 1:1; the carrier is specifically titanium dioxide, and the auxiliary agent is specifically composed of alkaline earth metal magnesium accounting for 3% of the total mass and rare earth element lanthanum accounting for 2% of the total mass.

[0041] Example 2 Beneficial Effects: The combined use of copper salt and manganese salt with titanium dioxide carrier enables the catalyst to exert high catalytic activity at different temperatures, further broadening the active temperature range. Alkaline earth metal magnesium and rare earth element lanthanum form stable compounds with impurities, enhancing the anti-poisoning ability. The good thermal stability and chemical stability of the titanium dioxide carrier ensure the stability of the catalyst. The metal salt catalyst for desulfurization and denitrification of this component performs well in a wide temperature range and may be more adaptable to complex flue gas.

[0042] Example 3: A metal salt catalyst for desulfurization and denitrification, comprising an active metal component: 25%, a carrier: 70%, and an auxiliary agent: 5%, wherein the active metal component is specifically a cobalt salt (cobalt chloride); the carrier is specifically a molecular sieve, and the auxiliary agent is specifically composed of 3% alkali metal potassium and 2% rare earth element yttrium of the total mass.

[0043] Example 3 Beneficial effects: Cobalt chloride as an active metal component exhibits good catalytic activity in a specific temperature range. When combined with a molecular sieve carrier with a regular pore structure, the selectivity of the catalyst for desulfurization and denitrification reactions is improved. Alkali metal potassium can adjust the surface acidity of the catalyst and enhance the adsorption of pollutants. The rare earth element yttrium improves the redox performance and thermal stability of the catalyst. The molecular sieve carrier has a large specific surface area and good adsorption properties. It can stably carry active components, prevent their agglomeration and loss, and extend the service life of the catalyst. The metal salt catalyst for desulfurization and denitrification of this component has higher selectivity for specific pollutants, and its performance is stable in the temperature range of 200°C to 400°C. It is especially suitable for working conditions with high selectivity requirements.

[0044] Embodiment 4: The metal salt catalyst for desulfurization and denitrification comprises an active metal component: 35%, a carrier: 60%, and an auxiliary agent: 5%, wherein the active metal component is specifically nickel salt (nickel nitrate); the carrier is specifically activated carbon, and the auxiliary agent is specifically composed of 3% of alkaline earth metal calcium and 2% of rare earth element europium of the total mass.

[0045] Example 4 Beneficial effects: Nickel nitrate as an active metal component exhibits good catalytic activity at medium and high temperatures. It cooperates with the rich pore structure of the activated carbon carrier to improve the contact efficiency with the flue gas and achieve efficient desulfurization and denitrification. Alkaline earth metal calcium and rare earth element europium reduce the impact of impurities on the catalyst and reduce the risk of poisoning. The high adsorption performance of the activated carbon carrier can not only adsorb pollutants, but also synergize with the active components to improve the catalytic performance, and has thermal stability to prevent the loss and sintering of active components. The metal salt catalyst for desulfurization and denitrification of this component has obvious advantages in the medium and high temperature range, has good resistance to impurities in complex flue gases, and is suitable for medium and high temperature complex flue gas treatment scenarios.

[0046] Comparative experiment:

[0047] 1. Purpose of the experiment

[0048] The performance of the metal salt catalysts for desulfurization and denitrification of different embodiments under different conditions is compared, including desulfurization efficiency, denitrification efficiency, active temperature range, anti-poisoning ability, etc.

[0049] 2. Experimental Materials and Equipment

[0050] Experimental Materials:

[0051] The metal salt catalysts of Examples 1 to 4.

[0052] Simulated flue gas contains a certain concentration of sulfur dioxide (SO 2 ), nitrogen oxides (NO x ) and other pollutants.

[0053] Other chemical reagents, such as standard solutions used for analysis, etc.

[0054] Experimental equipment:

[0055] Fixed bed reactor.

[0056] Flue gas analyzer, used to measure SO in flue gas 2 、NO x The concentration of pollutants.

[0057] A heating device is provided to control the reaction temperature.

[0058] Flow meter, used to control flue gas flow.

[0059] Electronic balance for weighing catalysts.

[0060] 3. Experimental steps

[0061] Catalyst preparation and pretreatment

[0062] Metal salt catalysts were prepared according to the formulations of Examples 1 to 4, and ground to a certain particle size.

[0063] The prepared catalyst is pretreated at a certain temperature, such as drying, calcining, etc., to remove moisture and impurities and activate the catalyst.

[0064] Experimental device construction

[0065] Connect the fixed bed reactor to the heating device, flue gas analyzer, flow meter and other equipment.

[0066] A certain amount of catalyst is loaded into the reactor to ensure that the catalyst is evenly distributed.

[0067] Simulated smoke configuration

[0068] According to the experimental requirements, different concentrations of SO 2 、NO x of simulated smoke.

[0069] A flow meter was used to control the flow of the simulated flue gas so that it passed through the reactor at a certain flow rate.

[0070] Experimental parameter settings

[0071] Different reaction temperatures are set to cover the active temperature ranges of various embodiments. For example, for embodiment 1, a temperature point in the medium-low temperature range can be set; for embodiment 4, a temperature point in the medium-high temperature range can be set.

[0072] The concentration of pollutants in the simulated flue gas is adjusted to simulate flue gas with different pollution levels.

[0073] Control the flue gas flow rate so that it varies within a reasonable range.

[0074] Experimental Procedure

[0075] Turn on the heating device to raise the temperature of the reactor to the set temperature.

[0076] Simulated flue gas was introduced to start the reaction.

[0077] At certain time intervals, the SO in the flue gas at the reactor outlet was measured using a flue gas analyzer. 2 、NO x concentration.

[0078] Record data such as temperature, flue gas flow, pollutant concentration, etc. at different time points.

[0079] Anti-poisoning experiment

[0080] A certain amount of impurities, such as dust, heavy metals, etc., are added to the simulated flue gas to simulate the complex components in the actual flue gas.

[0081] Repeat the above experimental process, observe the performance changes of the catalyst, and evaluate its anti-poisoning ability.

[0082] End of experiment and data processing

[0083] Turn off the heating device and flue gas supply and stop the experiment.

[0084] The experimental data were collated and analyzed, and performance indicators such as desulfurization efficiency and denitrification efficiency of catalysts of different embodiments under different conditions were calculated.

[0085] The catalysts of various embodiments are compared in terms of active temperature range, anti-poisoning ability, etc.

[0086] 4. Experimental Data

[0087] The following are examples of experimental data, and actual data may vary depending on experimental conditions and catalyst properties.

[0088] Embodiment 1: In the medium and low temperature range (e.g. 150°C-300°C), as the temperature increases, the desulfurization efficiency gradually increases from 80% to 90%, and the denitrification efficiency increases from 70% to 80%; after adding impurities, the desulfurization efficiency decreases by 5%, and the denitrification efficiency decreases by 8%.

[0089] Example 2: In a wide temperature range (eg, 200°C-450°C), the desulfurization efficiency fluctuates between 85%-95%, and the denitrification efficiency is between 75%-85%. After adding impurities, the desulfurization efficiency decreases by 3%, and the denitrification efficiency decreases by 6%.

[0090] Example 3: In the temperature range of 200°C-400°C, the desulfurization efficiency is stable at about 90%, and the denitrification efficiency is about 80%; after adding impurities, the desulfurization efficiency decreases by 4%, and the denitrification efficiency decreases by 7%.

[0091] Example 4: In the medium and high temperature range (e.g. 300°C-500°C), the desulfurization efficiency is increased from 85% to 95%, and the denitrification efficiency is increased from 75% to 85%; after adding impurities, the desulfurization efficiency decreases by 2%, and the denitrification efficiency decreases by 5%

[0092] Experimental conclusion:

[0093] 1. Active temperature range

[0094] Example 1: Good activity is shown in the medium and low temperature range (150°C-300°C). The ferrous sulfate in the catalyst works at medium and low temperatures, and combined with the adjustment of the acidity of the catalyst surface by alkali metal sodium and rare earth element cerium, it has a high desulfurization and denitrification efficiency in this temperature range.

[0095] Example 2: High catalytic activity in a wide temperature range (200°C-450°C) The combined use of copper salt and manganese salt and the good thermal stability of the titanium dioxide carrier enable it to maintain good performance in a relatively wide temperature range.

[0096] Example 3: Stable performance in the temperature range of 200° C.-400° C. Cobalt chloride as an active metal component combined with a molecular sieve carrier exhibits good catalytic activity and selectivity in this specific temperature range.

[0097] Example 4: Obvious advantages in the medium and high temperature range (300°C-500°C). The activity of nickel nitrate at medium and high temperatures, coupled with the high adsorption performance and thermal stability of the activated carbon carrier, makes it suitable for medium and high temperature flue gas treatment.

[0098] Example Active temperature range Embodiment 1 150℃-300℃ Embodiment 2 200℃-450℃ Embodiment 3 200℃-400℃ Embodiment 4 300℃-500℃

[0099] 2. Desulfurization and Denitrification Efficiency

[0100] Example 1: The desulfurization efficiency is gradually increased from 80% to 90% in the medium and low temperature range, and the denitrification efficiency is increased from 70% to 80%. Under medium and low temperature conditions, there is a certain effect on the removal of sulfur dioxide and nitrogen oxides, but compared with other examples, the efficiency improvement is relatively limited.

[0101] Example 2: The desulfurization efficiency fluctuates between 85% and 95%, and the denitration efficiency is between 75% and 85%. A high desulfurization and denitration efficiency can be maintained within a wide temperature range, and the performance is relatively stable.

[0102] Example 3: Desulfurization efficiency is stable at about 90%, and denitrification efficiency is about 80%. Within its specific temperature range, the removal effect of sulfur dioxide is relatively stable, and the denitrification efficiency is also at a high level.

[0103] Embodiment 4: The desulfurization efficiency is increased from 85% to 95%, and the denitrification efficiency is increased from 75% to 85%.

[0104] In the medium and high temperature range, as the temperature increases, the desulfurization and denitrification efficiencies are significantly improved.

[0105] Example Desulfurization efficiency Denitrification efficiency Embodiment 1 80％-90％ 70％-80％ Embodiment 2 85％-95％ 75％-85％ Embodiment 3 About 90% About 80% Embodiment 4 85％-95％ 75％-85％

[0106] 3. Anti-poisoning ability

[0107] Example 1: After adding impurities, the desulfurization efficiency decreased by 5%, and the denitrification efficiency decreased by 8%. The anti-poisoning ability is relatively weak, which may be due to the limited resistance of alkali metal sodium and rare earth element cerium to certain impurities.

[0108] Example 2: After adding impurities, the desulfurization efficiency decreased by 3%, and the denitrification efficiency decreased by 6%. The anti-poisoning ability is strong, and the alkaline earth metal magnesium and the rare earth element lanthanum form stable compounds with the impurities, which effectively reduces the impact of impurities on the catalyst performance.

[0109] Example 3: After adding impurities, the desulfurization efficiency decreased by 4%, and the denitrification efficiency decreased by 7%. The anti-poisoning ability is at a medium level. Alkali metal potassium and rare earth element yttrium can reduce the adsorption of impurities to a certain extent, but the effect is not as good as that of Example 2.

[0110] Example 4: After adding impurities, the desulfurization efficiency decreased by 2% and the denitrification efficiency decreased by 5%. The anti-poisoning ability is strong, the high adsorption performance of the activated carbon carrier can adsorb some impurities, and the alkaline earth metal calcium and rare earth element europium also play a role in enhancing the anti-poisoning ability.

[0111] Example Desulfurization efficiency decrease Denitrification efficiency decrease Embodiment 1 5％ 8％ Embodiment 2 3％ 6％ Embodiment 3 4％ 7％ Embodiment 4 2％ 5％

[0112] IV. Comprehensive Evaluation

[0113] Embodiment 1: The cost is relatively low, and it has certain advantages in the medium and low temperature range, but the anti-poisoning ability and efficiency improvement are limited. It is suitable for medium and low temperature working conditions with high cost requirements and relatively few flue gas impurities.

[0114] Example 2: Excellent performance in a wide temperature range, strong adaptability to complex flue gas, and good anti-poisoning ability. But the cost may be relatively high. Suitable for occasions with large temperature changes and complex flue gas components.

[0115] Example 3: Higher selectivity for specific pollutants, stable performance within a specific temperature range. However, there is still room for improvement in anti-poisoning ability and efficiency. Suitable for working conditions with high selectivity requirements and relatively stable temperature.

[0116] Example 4: It has obvious advantages in the medium and high temperature range, strong anti-poisoning ability, and good resistance to impurities in complex flue gas. However, its performance may be relatively weak at low temperatures. It is suitable for complex environments with medium and high temperatures and more flue gas impurities.

[0117]

[0118] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal salt catalyst for desulfurization and denitrification, characterized in that: It includes active metal components: 30% - 35%, carrier: 60% - 65%, and auxiliary agent: 5% - 10%.

2. The metal salt catalyst for desulfurization and denitrification according to claim 1, characterized in that: The active metal component is specifically ferrous sulfate.

3. The metal salt catalyst for desulfurization and denitrification according to claim 1, characterized in that: The carrier is specifically alumina.

4. The metal salt catalyst for desulfurization and denitrification according to claim 1, characterized in that: The auxiliary agent specifically consists of 3%-6% of alkali metal sodium and 2%-4% of rare earth element cerium.

5. A method for preparing a metal salt catalyst for desulfurization and denitrification according to any one of claims 1 to 4, comprising the following steps: S1. Raw material preparation: preparing active metal salts, carriers and additives, and pretreating the active metal salts, carriers and additives; S2. Preparation by impregnation method: dissolve the active metal salt in a suitable solvent, wherein the suitable solvent includes deionized water and ethanol, to form an impregnation solution; and immerse the pretreated carrier in the impregnation solution to adsorb the active metal salt on the surface of the carrier. Stirring, ultrasound and other methods can be used to promote the impregnation process and improve the impregnation effect. The impregnation time is 5 hours to 10 hours; take out the impregnated carrier, dry it at a certain temperature, and remove the solvent. The drying temperature is usually between 80℃ and 150℃; the dried catalyst is calcined at a certain temperature to convert the active metal salt into an active catalyst. The calcination temperature is determined according to the properties of the active metal salt and the performance requirements of the catalyst, generally between 300°C and 800°C. The calcination time is generally 5 to 10 hours; S3. Post-treatment: Grind the calcined catalyst to meet certain particle size requirements. Then remove oversized or undersized particles through screening to ensure the uniformity of the catalyst particle size; activate the catalyst by introducing reducing gas at a temperature of 200°C to 500°C to reduce the active metal ions on the catalyst surface to an active state; S4. Packaging and storage: Use cans or sealed bags to properly package the activated metal salt catalysts for desulfurization and denitrification to ensure that the performance of the catalyst is not affected during storage and transportation.

6. The method for preparing a metal salt catalyst for desulfurization and denitrification according to claim 5, characterized in that: The pretreatment of the active metal salt in step S1 specifically includes grinding the metal salt to meet the particle size requirements to increase the reaction activity and uniformity.

7. The method for preparing a metal salt catalyst for desulfurization and denitrification according to claim 5, characterized in that: The pretreatment of the carrier in step S1 specifically includes: pretreatment of the carrier to remove impurities and increase the specific surface area and porosity of the carrier, wherein the specific pretreatment methods include washing, drying and calcining.

8. The method for preparing a metal salt catalyst for desulfurization and denitrification according to claim 5, characterized in that: The pretreatment of the auxiliary agent in step S1 specifically includes grinding or dissolving the auxiliary agent so that it can be evenly dispersed in the catalyst system.

9. The method for preparing a metal salt catalyst for desulfurization and denitrification according to claim 5, characterized in that: The reducing gas in step S3 is specifically: the reducing gas includes hydrogen and carbon monoxide.

10. Application of a metal salt catalyst for desulfurization and denitrification, wherein the metal salt catalyst for desulfurization and denitrification as claimed in any one of claims 1 to 2 is applied in the field of industrial production, especially in the fields of environmental protection and energy.

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