Metal salt catalysts for desulfurization and denitrification, their preparation methods and applications

Abstract

This application relates to the field of chemical production and discloses a metal salt catalyst for desulfurization and denitrification, its preparation method, and its application. The catalyst comprises an active metal component of 30%-35%, a support of 60%-65%, and an additive of 5%-10%. The active metal component is specifically ferrous sulfate. The activity of the ferrous salt at medium and low temperatures, combined with the adjustment of the catalyst surface acidity by alkali metal sodium and rare earth element cerium, broadens the active temperature range. The support is specifically alumina. The additives consist of 3%-6% alkali metal sodium and 2%-4% rare earth element cerium by mass. Simultaneously, alkali metal sodium and rare earth element cerium can reduce impurity adsorption and enhance resistance to poisoning. This invention, through the rational selection of the active metal component, support, and additives, broadens the active temperature range of the catalyst, enabling it to adapt to flue gas temperature changes under different operating conditions, thus providing a wider range of applications for desulfurization and denitrification in industrial production.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, specifically to metal salt catalysts for desulfurization and denitrification, their preparation methods, and applications. Background Technology

[0002] With the continuous expansion of industrial production, especially the rapid development of chemical, steel, and power industries, the massive consumption of energy has led to serious air pollution problems. Among these, the emission of sulfur oxides and nitrogen oxides has become one of the main causes of air pollution, posing a significant threat to human health and the ecological environment. To address this challenge and achieve sustainable development, efficient desulfurization and denitrification technologies have become an urgent need in industrial production.

[0003] Currently widely used desulfurization and denitrification technologies have many shortcomings. On the one hand, many traditional catalysts have narrow active temperature ranges, making them unable to adapt to flue gas temperature variations under different operating conditions. For example, some catalysts are only effective at high temperatures, while their activity decreases significantly at medium and low temperatures. On the other hand, they lack resistance to poisoning; impurities in the flue gas, such as dust and heavy metals, can easily poison the catalysts, reducing their catalytic performance. Furthermore, existing catalysts suffer from poor stability; active components are prone to loss or sintering, and the thermal stability and mechanical strength of the support are insufficient for long-term use. In addition, they exhibit low selectivity for specific pollutants, failing to efficiently remove key pollutants from complex flue gases. Moreover, some existing catalysts are costly, limiting their large-scale application.

[0004] Given the various limitations of existing technologies, developing efficient and low-cost metal salt catalysts for desulfurization and denitrification has become an urgent priority. By rationally selecting active metal components, supports, and additives, and optimizing preparation methods, the active temperature range of the catalyst can be broadened, its resistance to poisoning can be enhanced, its stability and selectivity for specific pollutants can be improved, while simultaneously reducing costs. This not only helps meet increasingly stringent environmental standards but also provides a new solution for the sustainable development of industrial production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides metal salt catalysts for desulfurization and denitrification, their preparation methods, and applications. This solves the problems of existing desulfurization and denitrification technologies, such as narrow activity temperature range, insufficient resistance to poisoning, poor stability, and low selectivity for specific pollutants, which fail to meet the needs of industrial production.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a metal salt catalyst for desulfurization and denitrification, comprising an active metal component of 30%-35%, a support of 60%-65%, and an additive of 5%-10%.

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

[0008] Preferably, the carrier is aluminum oxide.

[0009] Preferably, the additives are composed of 3-6% sodium alkali metal and 2%-4% cerium rare earth element by mass.

[0010] A method for preparing metal salt catalysts for desulfurization and denitrification includes the following steps:

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

[0012] S2. Impregnation Method: The active metal salt is dissolved in a suitable solvent, including deionized water and ethanol, to form an impregnation solution. The pretreated support is then immersed in the impregnation solution, allowing the active metal salt to adsorb onto the support surface. Stirring and ultrasonication can be used to accelerate the impregnation process and improve the impregnation effect. The impregnation time is 5-10 hours. The impregnated support is then removed and dried at a specific temperature to remove the solvent. The drying temperature is typically between 80℃ and 150℃. The dried catalyst is then calcined at a specific temperature to convert the active metal salt into an active catalyst. The calcination temperature depends on the properties of the active metal salt and the performance requirements of the catalyst, generally between 300℃ and 800℃. The calcination time is typically 5-10 hours.

[0013] S3. Post-treatment: The calcined catalyst is ground to meet certain particle size requirements. Then, it is sieved to remove excessively large or small particles to ensure the uniformity of catalyst particle size. The catalyst is then activated by introducing a reducing gas at a temperature of 200℃ to 500℃ to reduce the active metal ions on the catalyst surface to their active state.

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

[0015] Preferably, the pretreatment of the active metal salt in step S1 specifically involves grinding the metal salt to meet the particle size requirements, thereby increasing the reactivity and uniformity.

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

[0017] Preferably, the pretreatment of the additive in step S1 specifically involves grinding or dissolving the additive so that it can be uniformly dispersed in the catalyst system.

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

[0019] The application of metal salt catalysts for desulfurization and denitrification is in industrial production, especially in environmental protection and energy sectors.

[0020] This invention provides a metal salt catalyst for desulfurization and denitrification, its preparation method, and its application. It has the following beneficial effects:

[0021] 1. By rationally selecting active metal components, carriers and additives, this invention broadens the active temperature range of the catalyst, enabling it to adapt to flue gas temperature changes under different operating conditions, and providing a wider range of application scenarios for desulfurization and denitrification in industrial production.

[0022] 2. This invention utilizes alkali metals and rare earth elements in the additives to reduce impurity adsorption and form stable compounds with impurities, significantly enhancing the catalyst's resistance to poisoning. At the same time, it can maintain stable performance under the influence of complex impurities in actual industrial flue gas, reducing maintenance costs and replacement frequency, and improving the efficiency and sustainability of industrial production.

[0023] 3. By selecting a support with high thermal stability and mechanical strength, and combining pretreatment and posttreatment steps in the preparation process, this invention greatly improves the stability of the catalyst. This not only ensures the stability of the catalyst's performance during long-term use, but also extends its service life, providing a reliable guarantee for the stable operation of industrial production.

[0024] 4. The different active metal components and carrier combinations of the present invention endow the catalyst with higher selectivity for specific pollutants. In complex flue gas environments, it can more effectively remove key pollutants, improve the overall desulfurization and denitrification effect, and meet increasingly stringent environmental protection requirements. Attached Figure Description

[0025] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1:

[0028] Please see the appendix Figure 1The present invention provides a metal salt catalyst for desulfurization and denitrification, comprising an active metal component of 30%, a support of 65%, and an additive of 5%, wherein the active metal component is specifically ferrous sulfate; the support is specifically alumina; and the additive is specifically composed of 3% sodium alkali metal and 2% cerium rare earth element by mass.

[0029] A method for preparing metal salt catalysts for desulfurization and denitrification includes the following steps:

[0030] S1. Raw material preparation: Prepare active metal salts, carriers, and additives;

[0031] Metal salts are ground to meet particle size requirements in order to increase reactivity and uniformity.

[0032] Simultaneously, the carrier is pretreated to remove impurities and increase its specific surface area and porosity. Specific pretreatment methods include cleaning, drying, and calcination.

[0033] The additives are then ground or dissolved to ensure uniform dispersion within the catalyst system.

[0034] S2. Impregnation Method: The active metal salt is dissolved in a suitable solvent, including deionized water and ethanol, to form an impregnation solution. The pretreated support is then immersed in the impregnation solution, allowing the active metal salt to adsorb onto the support surface. Stirring and ultrasonication can be used to accelerate the impregnation process and improve the impregnation effect. The impregnation time is 5-10 hours. The impregnated support is then removed and dried at a specific temperature to remove the solvent. The drying temperature is typically between 80℃ and 150℃. The dried catalyst is then calcined at a specific temperature to convert the active metal salt into an active catalyst. The calcination temperature depends on the properties of the active metal salt and the performance requirements of the catalyst, generally between 300℃ and 800℃. The calcination time is typically 5-10 hours.

[0035] S3. Post-treatment: The calcined catalyst is ground to meet certain particle size requirements. Then, it is sieved to remove excessively large or small particles to ensure the uniformity of catalyst particle size. The catalyst is then activated by introducing a reducing gas, including hydrogen and carbon monoxide, at a temperature of 200°C to 500°C to reduce the active metal ions on the catalyst surface to an active state.

[0036] S4. Packaging and Storage: Use tanks or sealed bags to properly package the activated desulfurization and denitrification metal salt catalysts to ensure that the performance of the catalysts is not affected during storage and transportation.

[0037] The application of metal salt catalysts for desulfurization and denitrification is in industrial production, especially in environmental protection and energy sectors.

[0038] Beneficial effects of Example 1: This catalyst, through the activity of iron salts at medium and low temperatures, combined with the adjustment of catalyst surface acidity by alkali metal sodium and rare earth element cerium, broadens the active temperature range. Simultaneously, alkali metal sodium and rare earth element cerium can reduce impurity adsorption and enhance resistance to poisoning. The high thermal stability and mechanical strength of the alumina support further improve the catalyst's stability. This composition of desulfurization and denitrification metal salt catalysts has greater advantages in the medium and low temperature range and is relatively cheaper.

[0039] Example 2: A metal salt catalyst for desulfurization and denitrification, comprising 40% active metal component, 50% support, and 5% additives. The active metal component is specifically a 1:1 mixture of copper salt (copper sulfate) and manganese salt (manganese sulfate). The support is specifically titanium dioxide, and the additives are specifically composed of 3% alkaline earth metal magnesium and 2% rare earth element lanthanum by mass.

[0040] Example 2: Beneficial Effects: The combined use of copper and manganese salts with a titanium dioxide support allows the catalyst to maintain 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 resistance to poisoning. The excellent thermal and chemical stability of the titanium dioxide support ensures the stability of the catalyst. This composition of desulfurization and denitrification metal salt catalysts exhibits excellent performance over a wide temperature range and may have stronger adaptability to complex flue gas conditions.

[0041] Example 3: A metal salt catalyst for desulfurization and denitrification, comprising 25% active metal component, 70% support, and 5% additives, wherein the active metal component is specifically cobalt salt (cobalt chloride); the support is specifically a molecular sieve; and the additives are specifically composed of 3% potassium alkali metal and 2% yttrium rare earth element by mass.

[0042] Example 3: Beneficial Effects: Cobalt chloride, as the active metal component, exhibits excellent catalytic activity within a specific temperature range. Combined with a molecular sieve support with a regular pore structure, it improves the selectivity of the catalyst for desulfurization and denitrification reactions. Alkali metal potassium can adjust the acidity of the catalyst surface and enhance the adsorption of pollutants, while the rare earth element yttrium improves the catalyst's redox performance and thermal stability. The molecular sieve support has a large specific surface area and good adsorption performance, stably supporting the active components, preventing their aggregation and loss, and extending the catalyst's lifespan. The desulfurization and denitrification metal salt catalyst with this composition shows higher selectivity for specific pollutants and exhibits stable performance within the temperature range of 200℃ to 400℃, making it particularly suitable for applications requiring high selectivity.

[0043] Example 4: A metal salt catalyst for desulfurization and denitrification, comprising an active metal component of 35%, a support of 60%, and an additive of 5%, wherein the active metal component is specifically a nickel salt (nickel nitrate); the support is specifically activated carbon; and the additive is specifically composed of 3% alkaline earth metal calcium and 2% rare earth element europium by mass.

[0044] Example 4: Beneficial Effects: Nickel nitrate, as the active metal component, exhibits good catalytic activity at medium and high temperatures. Combined with the rich porous structure of the activated carbon support, it improves the contact efficiency with flue gas, achieving efficient desulfurization and denitrification. Alkaline earth metal calcium and rare earth element europium reduce the impact of impurities on the catalyst, lowering the risk of poisoning. The high adsorption capacity of the activated carbon support not only adsorbs pollutants but also synergistically enhances catalytic performance with the active components, and possesses thermal stability, preventing the loss and sintering of active components. This composition of desulfurization and denitrification metal salt catalyst shows significant advantages in the medium and high temperature range, exhibits good resistance to impurities in complex flue gas, and is suitable for treating complex flue gas at medium and high temperatures.

[0045] Comparative experiment:

[0046] I. Experimental Objective

[0047] The performance of desulfurization and denitrification metal salt catalysts of different embodiments was compared under different conditions, including desulfurization efficiency, denitrification efficiency, activity temperature range, and resistance to poisoning.

[0048] II. Experimental Materials and Equipment

[0049] Experimental materials:

[0050] Metal salt catalysts of Examples 1 to 4.

[0051] The simulated flue gas contains a certain concentration of sulfur dioxide (SO2) and nitrogen oxides (NOx). x Pollutants such as )

[0052] Other chemical reagents, such as standard solutions used for analysis.

[0053] Experimental equipment:

[0054] Fixed-bed reactor.

[0055] Flue gas analyzer is used to measure SO2 and NO in flue gas. x The concentration of pollutants such as...

[0056] The heating device can control the reaction temperature.

[0057] A flow meter is used to control the flow rate of flue gas.

[0058] An electronic balance is used to weigh catalysts.

[0059] III. Experimental Procedure

[0060] Catalyst preparation and pretreatment

[0061] Metal salt catalysts were prepared according to the formulations of Examples 1 to 4, and then ground to a certain particle size.

[0062] The prepared catalyst is pretreated at a certain temperature, such as by drying or calcining, to remove moisture and impurities and activate the catalyst.

[0063] Experimental setup

[0064] Connect the fixed-bed reactor to the heating device, flue gas analyzer, flow meter, and other equipment.

[0065] A certain amount of catalyst is loaded into the reactor to ensure that the catalyst is evenly distributed.

[0066] Simulated flue gas configuration

[0067] According to the experimental requirements, preparations were made containing different concentrations of SO2 and NO. x Simulated flue gas.

[0068] A flow meter is used to control the flow rate of the simulated flue gas, allowing it to pass through the reactor at a certain velocity.

[0069] Experimental parameter settings

[0070] Different reaction temperatures can be set, covering the activity temperature range of each embodiment. 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.

[0071] Adjust the concentration of pollutants in the simulated flue gas to simulate flue gas with different levels of pollution.

[0072] Control the flue gas flow rate to keep it within a reasonable range.

[0073] Experimental process

[0074] Turn on the heating device to raise the reactor temperature to the set temperature.

[0075] Simulated flue gas is introduced, and the reaction begins.

[0076] At certain time intervals, SO2 and NO in the flue gas at the reactor outlet are measured using a flue gas analyzer. x The concentration.

[0077] Record data such as temperature, flue gas flow rate, and pollutant concentration at different time points.

[0078] Anti-poisoning experiment

[0079] A certain amount of impurities, such as dust and heavy metals, are added to simulated flue gas to simulate the complex components in actual flue gas.

[0080] Repeat the above experimental procedure, observe the performance changes of the catalyst, and evaluate its resistance to poisoning.

[0081] Experiment End and Data Processing

[0082] Turn off the heating device and flue gas supply, and stop the experiment.

[0083] The experimental data were organized and analyzed, and the performance indicators such as desulfurization efficiency and denitrification efficiency of the catalysts in different embodiments under different conditions were calculated.

[0084] The differences between the catalysts of the various embodiments in terms of active temperature range, resistance to poisoning, etc., are compared.

[0085] IV. Experimental Data

[0086] The following are examples of experimental data. Actual data may vary depending on experimental conditions and catalyst performance.

[0087] Example 1: In the medium and low temperature range (e.g., 150℃-300℃), 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%.

[0088] Example 2: Over a wide temperature range (e.g., 200℃-450℃), the desulfurization efficiency fluctuates between 85% and 95%, and the denitrification efficiency is between 75% and 85%. After the addition of impurities, the desulfurization efficiency decreases by 3%, and the denitrification efficiency decreases by 6%.

[0089] Example 3: In the temperature range of 200℃-400℃, 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%.

[0090] Example 4: In the medium-high temperature range (e.g., 300℃-500℃), the desulfurization efficiency increased from 85% to 95%, and the denitrification efficiency increased from 75% to 85%; after adding impurities, the desulfurization efficiency decreased by 2%, and the denitrification efficiency decreased by 5%.

[0091] Experimental conclusion:

[0092] I. Active Temperature Range

[0093] Example 1: This catalyst exhibits good activity in the medium-low temperature range (150℃-300℃). The ferrous sulfate in the catalyst functions effectively at these temperatures, and the combination of alkali metal sodium and rare earth element cerium modulates the acidity of the catalyst surface, resulting in high desulfurization and denitrification efficiency within this temperature range.

[0094] Example 2: High catalytic activity was observed over a wide temperature range (200℃-450℃). The combined use of copper and manganese salts, along with the excellent thermal stability of the titanium dioxide support, enabled it to maintain good performance over a relatively wide temperature range.

[0095] Example 3: Stable performance within the temperature range of 200℃-400℃. The combination of cobalt chloride as the active metal component and the molecular sieve support exhibits good catalytic activity and selectivity within this specific temperature range.

[0096] Example 4: Significant advantages in the medium-high temperature range (300℃-500℃). The activity of nickel nitrate at medium-high temperatures, combined with the high adsorption performance and thermal stability of the activated carbon carrier, makes it suitable for flue gas treatment at medium-high temperatures.

[0097] Example Active temperature range Example 1 150℃-300℃ Example 2 200℃-450℃ Example 3 200℃-400℃ Example 4 300℃-500℃

[0098] II. Desulfurization and denitrification efficiency

[0099] Example 1: The desulfurization efficiency gradually increased from 80% to 90% in the medium and low temperature range, and the denitrification efficiency increased from 70% to 80%. Under medium and low temperature conditions, it has a certain effect on the removal of sulfur dioxide and nitrogen oxides, but the efficiency improvement is relatively limited compared to other examples.

[0100] Example 2: The desulfurization efficiency fluctuates between 85% and 95%, and the denitrification efficiency is between 75% and 85%. It maintains high desulfurization and denitrification efficiency over a wide temperature range, demonstrating relatively stable performance.

[0101] Example 3: The desulfurization efficiency remained stable at around 90%, and the denitrification efficiency at around 80%. Within its specific temperature range, the removal effect on sulfur dioxide was relatively stable, and the denitrification efficiency was also at a high level.

[0102] Example 4: Desulfurization efficiency increased from 85% to 95%, and denitrification efficiency increased from 75% to 85%.

[0103] In the medium- and high-temperature range, the desulfurization and denitrification efficiency increases significantly with the increase of temperature.

[0104] Example Desulfurization efficiency Denitrification efficiency Example 1 80％-90％ 70％-80％ Example 2 85％-95％ 75％-85％ Example 3 Around 90% Around 80% Example 4 85％-95％ 75％-85％

[0105] 3. Anti-poisoning ability

[0106] Example 1: After adding impurities, the desulfurization efficiency decreased by 5% and the denitrification efficiency decreased by 8%. The relatively weak resistance to poisoning may be due to the limited resistance of alkali metal sodium and rare earth element cerium to certain impurities.

[0107] Example 2: After adding impurities, the desulfurization efficiency decreased by 3% and the denitrification efficiency decreased by 6%. It exhibits strong resistance to poisoning; the alkaline earth metal magnesium and the rare earth element lanthanum form stable compounds with the impurities, effectively reducing the impact of the impurities on the catalyst performance.

[0108] Example 3: After adding impurities, the desulfurization efficiency decreased by 4% and the denitrification efficiency decreased by 7%. The resistance to poisoning was at a moderate level. Alkali metal potassium and rare earth element yttrium can reduce the adsorption of impurities to some extent, but the effect is not as good as in Example 2.

[0109] Example 4: After adding impurities, the desulfurization efficiency decreased by 2% and the denitrification efficiency decreased by 5%. It exhibits strong resistance to poisoning; the high adsorption capacity of the activated carbon carrier can adsorb some impurities, and the alkaline earth metal calcium and rare earth element europium also enhance the resistance to poisoning.

[0110] Example Decrease in desulfurization efficiency The decrease in denitrification efficiency Example 1 5％ 8％ Example 2 3％ 6％ Example 3 4％ 7％ Example 4 2％ 5％

[0111] IV. Comprehensive Evaluation

[0112] Example 1: Relatively low cost, with certain advantages in the medium and low temperature range, but limited improvement in resistance to poisoning and efficiency. Suitable for medium and low temperature operating conditions, where cost requirements are high and flue gas impurities are relatively few.

[0113] Example 2: Performs excellently over a wide temperature range, exhibits strong adaptability to complex flue gases, and demonstrates good resistance to poisoning. However, the cost may be relatively high. Suitable for applications with significant temperature variations and complex flue gas composition.

[0114] Example 3: It exhibits higher selectivity for specific pollutants and stable performance within a specific temperature range. However, there is still room for improvement in terms of resistance to poisoning and efficiency. It is suitable for operating conditions requiring high selectivity and relatively stable temperatures.

[0115] Example 4: It exhibits significant advantages in the medium-to-high temperature range, strong resistance to poisoning, and good resistance to impurities in complex flue gas. However, its performance may be relatively weaker at low temperatures. It is suitable for complex environments with medium-to-high temperatures and a high concentration of impurities in the flue gas.

[0116]

[0117]

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

Claims

1. The application of metal salt catalysts for desulfurization and denitrification, characterized in that, It is used in the desulfurization and denitrification of flue gas in industrial production. The desulfurization and denitrification metal salt catalyst comprises an active metal component of 30%–35%, a support of 60%–65%, and an additive of 5%–10%. Specifically, the active metal component is ferrous sulfate, the support is alumina, and the additive is composed of 3%–6% sodium alkali metal and 2%–4% cerium rare earth element by mass.

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