Low-temperature sulfur-resistant SCR (Selective Catalytic Reduction) denitration catalyst of active coke carrier and preparation method thereof
By loading manganese oxide and iron oxide onto an activated coke support, the problems of low catalytic activity and poor sulfur resistance of SCR denitrification catalysts under low temperature conditions were solved, achieving efficient low-temperature denitrification and sulfur resistance performance, and reducing production costs.
Patent Information
- Application Number
- CN202511499280.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2026-01-02
AI Technical Summary
Existing SCR denitrification catalysts have low catalytic activity and poor sulfur resistance at low temperatures, making them susceptible to corrosion by fly ash, heavy metals and SO2, and causing deactivation due to sulfate formation.
Using activated coke as a carrier, manganese oxide and iron oxide are prepared by grinding activated coke particles and impregnating them with manganese and iron salt solutions, and then loading them into the pores of activated coke. The multiple chemical valence states of manganese oxide and the defect sites of iron oxide are used to enhance the low-temperature denitrification activity and sulfur resistance of the catalyst.
This improved the denitrification efficiency and sulfur resistance of the catalyst under low-temperature conditions, reduced the combination of SO2 with active materials, enhanced the catalyst's sulfur resistance, and reduced the catalyst's production cost.
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Figure CN121244232A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of flue gas denitration treatment technology, in particular to a low-temperature sulfur-resistant SCR denitration catalyst with activated coke carrier and a preparation method thereof. BACKGROUND
[0002] NO x As a key pollutant of power emission, it is an important factor leading to acid rain, photochemical smog, PM2.5 and greenhouse effect. The SCR technology is to generate harmless N2 and water by using ammonia (NH3) as a reducing agent to react with NO on the surface of the catalyst. The NH3-SCR denitration technology generally uses V2O5-WO3(MoO3) / TiO2 catalyst, and the best activity window of which is as high as 350-400℃. Therefore, the catalyst can only be arranged upstream of dust and desulfurization, which leads to continuous erosion of the catalyst by fly ash, heavy metals, SO2 and moisture. If the catalyst is arranged in the low-temperature section (150-250℃) of the flue gas duct, the catalytic activity is easily reduced, and a small amount of SO2 still exists in the flue gas in the low-temperature section of the flue gas duct, which is easy to generate sulfates with the catalyst, causing sulfur poisoning of the catalyst and reducing the catalytic activity of the catalyst.
[0003] Therefore, in the related art, the catalyst has problems of low catalytic activity under low-temperature conditions and poor sulfur resistance. SUMMARY
[0004] The present application aims to solve at least one of the problems in the prior art. To this end, one object of the present application is to provide a preparation method of a low-temperature sulfur-resistant SCR denitration catalyst with activated coke carrier, which has high catalytic activity under low-temperature conditions and good sulfur resistance.
[0005] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst with activated coke carrier according to the first aspect of the present application comprises the following steps: Step (1), activated coke pretreatment: grinding columnar activated coke particles to obtain activated coke particles of 40-60 mesh, soaking in 20% HNO3 solution for 12h, then washing with deionized water until the pH value is 7, and drying to obtain the activated coke carrier; Step (2), preparation of the catalyst: preparing a mixed solution by adding water to manganese salt and iron salt, adding the activated coke carrier obtained in step (1) into the mixed solution, and then performing ultrasonic treatment, impregnation, drying and calcination to obtain the low-temperature sulfur-resistant SCR denitration catalyst with activated coke as the carrier after cooling.
[0006] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the embodiment of the present application, by grinding the columnar active coke particles, the active coke particles with a particle size of 40-60 meshes can enhance the etching effect of the nitric acid solution on the inner pores of the active coke particles in the pretreatment process, which is conducive to the loading of the active substances and the enhancement of the physical adsorption effect of the active coke on SO2, so that SO2 is fixed in the pores of the active coke, the combination of SO2 and the active substances is reduced, and the sulfur resistance of the catalyst is enhanced; and by immersing the active coke in a mixed solution of manganese salt and iron salt, the manganese salt and the iron salt are fully immersed in the pores of the active coke, after drying and calcining, the manganese oxide and the iron oxide can be loaded in the pores in the active coke, the multiple chemical valence states of the manganese oxide can enhance the low-temperature denitration activity of the catalyst, the cation defect sites, anion defect sites and interstitial defect sites in the iron oxide are conducive to the generation of oxygen vacancies and activated oxygen molecules, so as to enhance the low-temperature catalytic activity of the catalyst, the iron sulfate is generated by the reaction of the iron oxide and SO2 in the flue gas, and the addition of NH3 in the SCR reaction can promote the decomposition of the iron sulfate to release the active sites of iron, so as to enhance the sulfur resistance of the catalyst.
[0007] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (1), the grinding time of the columnar active coke particles is 20-30 min.
[0008] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the manganese salt is manganese nitrate or manganese sulfate.
[0009] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the iron salt is ferric nitrate or ferric sulfate.
[0010] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the drying temperature is 100-110℃, and the drying time is 10-15h.
[0011] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the ultrasonic temperature is 20-30℃, and the ultrasonic time is 30-60 min.
[0012] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the heating rate of the calcination is 5-10℃ / min.
[0013] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the step (2), the calcination temperature is 300-500 DEG C, and the calcination time is 3-5 h.
[0014] The low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the second aspect of the embodiments of the present application comprises the active coke carrier and the manganese oxide and the iron oxide supported on the active coke carrier, and is prepared by the preparation method according to the first aspect of the embodiments of the present application.
[0015] The low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the embodiments of the present application is prepared by the preparation method of the first aspect of the embodiments of the present application, the columnar active coke particles are ground to obtain the active coke particles with a particle size of 40-60 meshes, the active coke particles with the suitable particle size can enhance the etching effect of the nitric acid solution on the inner pores of the active coke particles in the pretreatment process, are conducive to the loading of the active substances, and are also conducive to enhancing the physical adsorption effect of the active coke on SO2, so that SO2 is fixed in the pores of the active coke, the combination of SO2 and the active substances is reduced, and the sulfur resistance of the catalyst is enhanced; and by immersing the active coke in the mixed solution of the manganese salt and the iron salt, the manganese salt and the iron salt are fully immersed in the pores of the active coke, after drying and calcination, the manganese oxide and the iron oxide can be loaded in the pores of the active coke, the low-temperature denitration activity of the catalyst can be enhanced by using the multiple chemical valence states of the manganese oxide, the low-temperature catalytic activity of the catalyst can be enhanced by using the cation defect sites, the anion defect sites and the interstitial defect sites in the iron oxide, so as to generate oxygen vacancies and activated oxygen molecules, the sulfur resistance of the catalyst is enhanced by the reaction of the iron oxide and SO2 in the flue gas to generate metal sulfates, the addition of NH3 in the SCR reaction promotes the decomposition of the metal sulfates to release the active sites of iron, and the sulfur resistance of the catalyst is enhanced.
[0016] The low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in the catalyst, the content of the active coke is 90-98 wt%, the content of the manganese salt is 1-5 wt%, and the content of the iron salt is 1-5 wt%. Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS
[0017] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings, in which: Figure 1 is a flowchart of the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application; Figure 2is an activity test graph of a catalyst sample prepared according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to Embodiment 1 of the present application; Figure 3 is an activity test graph of a catalyst sample prepared according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to Embodiment 2 of the present application; Figure 4 is an activity test graph of a catalyst sample prepared according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to Embodiment 3 of the present application; Figure 5 is an activity test graph of a catalyst sample prepared according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to Embodiment 4 of the present application; Figure 6 is an activity test graph of a catalyst sample prepared according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to Embodiment 5 of the present application; Figure 7 is an activity test graph of a catalyst sample of Comparative Example 1; Figure 8 is an activity test graph of a catalyst sample of Comparative Example 2; Figure 9 is an activity test graph of a catalyst sample of Comparative Example 3; Figure 10 is an activity test graph of a catalyst sample of Comparative Example 4. DETAILED DESCRIPTION
[0018] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.
[0019] Reference is made below to Figure 1 A preparation method of a low-temperature sulfur-resistant SCR denitration catalyst of an active coke carrier according to an embodiment of the present application is described below.
[0020] Reference is made to Figure 1 The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the first aspect embodiment of the present application comprises the following steps: Step (1), active coke pretreatment: grinding columnar active coke particles to obtain 40-60 mesh active coke particles, soaking in 20% HNO3 solution for 12 h, washing with deionized water until the pH value is 7, and drying to obtain an active coke carrier; for example, the mesh number of the active coke particles can be 40 mesh, 45 mesh, 50 mesh, 55 mesh, 60 mesh, etc.; if the mesh number of the active coke particles is too small, the particle size is too large, and the etching of the pores of the active coke particles in the HNO3 solution treatment is not obvious; if the mesh number of the active coke particles is too large, the particle size is too small, and the pores of the active coke particles are prone to collapse during subsequent calcination; grinding the active coke particles to an appropriate mesh number can enhance the etching effect of the nitric acid solution on the pores of the active coke particles during the pretreatment process, which is beneficial to the loading of active substances and also beneficial to enhancing the physical adsorption effect of the active coke on SO2, so that SO2 macromolecules are fixed in the pores of the active coke, reducing the combination of SO2 and active substances, and enhancing the sulfur resistance of the catalyst. Step (2), preparation of the catalyst: adding manganese salt and iron salt to water to prepare a mixed solution, adding the active coke carrier obtained in step (1) to the mixed solution, and after ultrasonic treatment, immersion, drying and calcination, the low-temperature sulfur-resistant SCR denitration catalyst with active coke as the carrier is obtained after cooling; immersing the active coke in the mixed solution of manganese salt and iron salt, so that the manganese salt and iron salt are fully immersed in the pores of the active coke, and after drying and calcination, manganese oxide and iron oxide can be loaded in the pores of the active coke; the multiple chemical valence states of manganese oxide can enhance the low-temperature denitration activity of the catalyst, and the existence of cation defect sites, anion defect sites and interstitial defect sites in iron oxide is beneficial to the generation of oxygen vacancies and activated oxygen molecules, thereby enhancing the low-temperature catalytic activity of the catalyst; iron oxide reacts with SO2 in the flue gas to generate metal sulfate, and the addition of NH3 in the SCR reaction can promote the decomposition of metal sulfate and release the active sites of iron, thereby enhancing the sulfur resistance of the catalyst.
[0021] The preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the embodiment of the present application is characterized in that: the columnar active coke particles are ground to obtain active coke particles with a particle size of 40-60 meshes; the active coke particles with a suitable particle size can enhance the etching effect of the nitric acid solution on the pores of the active coke particles in the pretreatment process, which is conducive to the loading of active substances and also conducive to enhancing the physical adsorption effect of the active coke on SO2, so that SO2 is fixed in the pores of the active coke, the combination of SO2 and active substances is reduced, and the sulfur resistance of the catalyst is enhanced; and the active coke is immersed in a mixed solution of manganese salt and iron salt, so that the manganese salt and the iron salt are fully immersed in the pores of the active coke; after drying and calcination, manganese oxide and iron oxide can be loaded in the pores of the active coke; the multiple chemical valence states of manganese oxide can enhance the low-temperature denitration activity of the catalyst; the cation defect sites, anion defect sites and interstitial defect sites in the iron oxide are conducive to generating oxygen vacancies and activated oxygen molecules, thereby enhancing the low-temperature catalytic activity of the catalyst; the iron sulfate generated by the reaction of the iron oxide and SO2 in the flue gas promotes the decomposition of the metal sulfate and releases the active sites of iron, thereby enhancing the sulfur resistance of the catalyst.
[0022] In step (1), the grinding time of the columnar active coke particles is 20-30 min according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application.
[0023] For example, in step (1), the grinding time of the columnar active coke particles can be 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, etc.; if the grinding time is too short, the particle size of the active coke particles is too large, and the etching of the pores of the active coke particles by the HNO3 solution is not obvious; if the grinding time is too long, the particle size of the active coke particles is too small, and the pores of the active coke particles are prone to collapse during calcination.
[0024] In step (1), the grinding time of the columnar active coke particles is 20-30 min according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application.
[0025] In step (2), the manganese salt is manganese nitrate or manganese sulfate according to the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application. The manganese nitrate and the manganese sulfate are inexpensive and easy to obtain and dissolve in water; by using manganese nitrate or manganese sulfate, it is convenient to configure them into a solution and load them into the pore structure of the active coke, and then oxidize the manganese salt to manganese oxide under high-temperature conditions, which can also reduce the production cost of the catalyst.
[0026] In the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in step (2), the iron salt is ferric nitrate or ferric sulfate. Among them, ferric nitrate and ferric sulfate are low in price and easy to obtain and dissolve in water. By using ferric nitrate or ferric sulfate, it is convenient to configure them into a solution and load them into the pore structure of the active coke, and then oxidize the iron salt into iron oxide under high temperature conditions, which can also reduce the production cost of the catalyst.
[0027] In the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in step (2), the drying temperature is 100-110℃, and the drying time is 10-15h.
[0028] For example, in step (2), the drying temperature can be 100℃, 102℃, 104℃, 106℃, 108℃, 110℃, etc.; the drying time can be 10h, 11h, 12h, 13h, 14h, 15h, etc.; if the drying temperature is too high or the drying time is too long, the pore structure of the active coke will be easily damaged, and if the calcination time is too short or the temperature is too low, the water will not be fully evaporated.
[0029] By setting the drying temperature to 100-110℃ and the drying time to 10-15h in step (2), the water in the active coke can be fully evaporated, and the pore collapse of the active coke caused by too long drying time can be avoided, so that the structural strength of the obtained active coke is higher.
[0030] In the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in step (2), the ultrasonic temperature is 20-30℃, and the ultrasonic time is 30-60min.
[0031] For example, in step (2), the ultrasonic temperature can be 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, etc.; the ultrasonic time can be 30min, 40min, 50min, 60min, etc.; if the ultrasonic temperature is too low or the ultrasonic time is too short, the active coke and the manganese salt and the iron salt cannot be fully mixed, and if the ultrasonic temperature is too high or the ultrasonic time is too long, the pore structure of the active coke will be damaged.
[0032] By setting the ultrasonic temperature to 20-30℃ and the ultrasonic time to 30-60min in step (2), the active coke and the salt and the iron salt can be fully mixed, and the pore structure of the active coke can be prevented from being damaged, so that the active coke has good structural strength.
[0033] In the preparation method of the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in step (2), the heating rate of calcination is 5-10℃ / min.
[0034] For example, in step (2), the heating rate of calcination can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, etc.
[0035] By gradually increasing the temperature during step (2), the water in the active coke can be slowly evaporated, avoiding the collapse of the pores in the active coke due to the rapid evaporation of water molecules, so that the structural strength of the obtained active coke is higher.
[0036] According to the method for preparing the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to some embodiments of the present application, in step (2), the calcination temperature is 300-500℃, and the calcination time is 3-5h.
[0037] For example, in step (2), the calcination temperature can be 300℃, 350℃, 400℃, 450℃, 500℃, etc.; the calcination time can be 3h, 3.5h, 4h, 4.5h, 5h, etc.; if the calcination time is too long or the temperature is too high, the pore structure of the active coke will be damaged, and if the calcination time is too short or the temperature is too low, the manganese salt and the iron salt cannot be fully oxidized.
[0038] By setting the calcination temperature to 300-500℃ and the calcination time to 3-5h in step (2), the manganese salt and the iron salt can be fully oxidized to manganese oxide and iron oxide while avoiding the damage to the pore structure of the active coke.
[0039] The low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the second aspect of the embodiments of the present application comprises an active coke carrier and manganese oxide and iron oxide supported on the active coke carrier, and is prepared by the method according to the first aspect of the embodiments of the present application.
[0040] The manganese-based catalyst has high low-temperature activity, and the manganese oxide has multiple chemical valence states, which is conducive to accelerating the removal efficiency of nitrogen oxides through redox reactions, thereby enhancing the low-temperature denitration activity of the catalyst; the iron oxide has cation defect sites, anion defect sites and interstitial defect sites, which is conducive to generating oxygen vacancies and activated oxygen molecules, thereby enhancing the low-temperature catalytic activity of the catalyst; the iron oxide reacts with SO2 in the flue gas to generate metal sulfates, and the addition of NH3 in the SCR reaction can promote the decomposition of the metal sulfates to regenerate the iron oxide and release the active sites of iron, thereby enhancing the sulfur resistance of the catalyst.
[0041] The low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier according to the embodiment of the present application is prepared by the method according to the first aspect of the present application, and the columnar active coke particles are ground to obtain active coke particles with a particle size of 40-60 mesh. The active coke particles with a suitable particle size can enhance the etching effect of the nitric acid solution on the inner pores of the active coke particles in the pretreatment process, which is conducive to the loading of the active substances and the enhancement of the physical adsorption effect of the active coke on SO2, so that SO2 is fixed in the pores of the active coke, the combination of SO2 and the active substances is reduced, and the sulfur resistance of the catalyst is enhanced. Furthermore, the active coke is immersed in a mixed solution of manganese salt and iron salt, so that the manganese salt and the iron salt are fully impregnated in the pores of the active coke. After drying and calcination, manganese oxide and iron oxide can be loaded in the pores of the active coke. The multiple chemical valence states of manganese oxide can enhance the low-temperature denitration activity of the catalyst. The cation defect sites, anion defect sites and interstitial defect sites in the iron oxide are conducive to the generation of oxygen vacancies and activated oxygen molecules, thereby enhancing the low-temperature catalytic activity of the catalyst. The iron oxide reacts with SO2 in the flue gas to generate metal sulfate, and the addition of NH3 in the SCR reaction can promote the decomposition of the metal sulfate and release the active sites of iron, thereby enhancing the sulfur resistance of the catalyst.
[0042] According to some embodiments of the present application, the content of the active coke in the low-temperature sulfur-resistant SCR denitration catalyst of the active coke carrier is 90-98wt%, the content of the manganese salt is 1-5wt%, and the content of the iron salt is 1-5wt%. For example, the content of the active coke in the catalyst can be 90wt%, 92wt%, 94wt%, 96wt%, 98wt%, etc.; the content of the manganese oxide can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc.; and the content of the iron oxide can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc. If the content of the manganese oxide is too low or the content of the iron oxide is too low, the content of the active substances is too low, and the catalytic performance is low. If the content of the manganese oxide is too high or the content of the iron oxide is too high, the manganese oxide and the iron oxide loaded in the active coke are more likely to aggregate to form large particles, which reduces the dispersion degree of the manganese oxide and the iron oxide, and is not conducive to the contact between the flue gas and the active substances.
[0043] By making the content of active coke 90-98wt%, the content of manganese salt 1-5wt%, and the content of iron salt 1-5wt%, the dispersion of manganese oxide and iron oxide is improved, the manganese oxide and iron oxide as active substances can be more uniformly loaded on the active coke, thereby further improving the catalytic activity of the catalyst under low temperature conditions, and by making the content of active coke larger, the proportion of the pore structure of the active coke can be increased, more SO2 molecules can be accommodated and fixed, thereby reducing the contact between the active substance and SO2, enhancing the sulfur poisoning resistance of the catalyst, and the price of active coke is lower than that of metal salt, which is also beneficial to reducing the preparation cost of the catalyst.
[0044] The low-temperature sulfur-resistant SCR denitration catalyst with the active coke carrier and the preparation method thereof will be further described below in combination with examples.
[0045] Example 1, The low-temperature sulfur-resistant SCR denitration catalyst of the present application has an active coke carrier content of 90wt%, a manganese salt content of 5wt%, and an iron salt content of 5wt%, and the preparation method thereof comprises the following steps: (1) Active coke pretreatment: the columnar active coke particles are crushed and sieved to obtain active coke particles with a size of 40-60 mesh, then soaked in a 20% HNO3 solution for 12 h, washed with deionized water until the pH value is 7, and dried to obtain the required active coke carrier; (2) Catalyst preparation by ultrasonic impregnation method: 9.0g of the active coke carrier obtained in step (1), 0.5g of Mn(NO3)2 (AR, from Sinopharm), and 0.5g of Fe(NO3)3·9H2O (AR, from Sinopharm) are dissolved in 100mL of deionized water, ultrasonically treated for 40min, then left to stand for 4h, dried at 105℃ for 24h, heated to 400℃ at a rate of 10℃ / min under a nitrogen atmosphere, and calcined for 4h, and then naturally cooled to obtain the catalyst sample.
[0046] Example 2, The low-temperature sulfur-resistant SCR denitration catalyst of the present application has an active coke carrier content of 92wt%, a manganese salt content of 4wt%, and an iron salt content of 4wt%, and the preparation method thereof comprises the following steps: (1) Active coke pretreatment: the columnar active coke particles are crushed and sieved to obtain active coke particles with a size of 40-60 mesh, then soaked in a 20% HNO3 solution for 12 h, washed with deionized water until the pH value is 7, and dried to obtain the required active coke carrier; (2) Catalyst preparation by ultrasonic immersion method: 9.2 g of the active coke carrier obtained in step (1), 0.4 g of Mn(NO3)2 (National Pharmaceutical, AR), and 0.4 g of Fe(NO3)3·9H2O (National Pharmaceutical, AR) were dissolved in 100 mL of deionized water, and ultrasonic treatment was performed for 40 min. After standing for 4 h, drying was performed at 105°C for 24 h. The temperature was increased to 400°C at a rate of 10°C / min under a nitrogen atmosphere, and calcination was performed for 4 h. After natural cooling, a catalyst sample was obtained.
[0047] Example 3, The low-temperature sulfur-resistant SCR denitration catalyst of the present application has an active coke carrier content of 94 wt%, a manganese salt content of 3 wt%, and an iron salt content of 3 wt%. The preparation method comprises the following steps: (1) Active coke pretreatment: The columnar active coke particles were crushed and sieved to obtain active coke particles with a size of 40-60 mesh. After being soaked in a 20% HNO3 solution for 12 h, the particles were washed with deionized water until the pH value was 7. After drying, the desired active coke carrier was obtained. (2) Catalyst preparation by ultrasonic immersion method: 9.4 g of the active coke carrier obtained in step (1), 0.3 g of Mn(NO3)2 (National Pharmaceutical, AR), and 0.3 g of Fe(NO3)3·9H2O (National Pharmaceutical, AR) were dissolved in 100 mL of deionized water, and ultrasonic treatment was performed for 40 min. After standing for 4 h, drying was performed at 105°C for 24 h. The temperature was increased to 400°C at a rate of 10°C / min under a nitrogen atmosphere, and calcination was performed for 4 h. After natural cooling, a catalyst sample was obtained.
[0048] Example 4, The low-temperature sulfur-resistant SCR denitration catalyst of the present application has an active coke carrier content of 96 wt%, a manganese salt content of 2 wt%, and an iron salt content of 2 wt%. The preparation method comprises the following steps: (1) Active coke pretreatment: The columnar active coke particles were crushed and sieved to obtain active coke particles with a size of 40-60 mesh. After being soaked in a 20% HNO3 solution for 12 h, the particles were washed with deionized water until the pH value was 7. After drying, the desired active coke carrier was obtained. (2) Catalyst preparation by ultrasonic immersion method: 9.6 g of the active coke carrier obtained in step (1), 0.2 g of Mn(NO3)2 (National Pharmaceutical, AR), and 0.2 g of Fe(NO3)3·9H2O (National Pharmaceutical, AR) were dissolved in 100 mL of deionized water, and ultrasonic treatment was performed for 40 min. After standing for 4 h, drying was performed at 105°C for 24 h. The temperature was increased to 400°C at a rate of 10°C / min under a nitrogen atmosphere, and calcination was performed for 4 h. After natural cooling, a catalyst sample was obtained.
[0049] Example 5, The low-temperature sulfur-resistant SCR denitration catalyst of the application has an active coke carrier content of 98 wt%, a manganese salt content of 1 wt%, and an iron salt content of 1 wt%, and the preparation method comprises the following steps: (1) Active coke pretreatment: columnar active coke particles are crushed and sieved to obtain active coke particles with a size of 40-60 mesh, soaked in a 20% HNO3 solution for 12 h, washed with deionized water until the pH value is 7, and dried to obtain the required active coke carrier; (2) Catalyst preparation by ultrasonic impregnation: 9.8 g of the active coke carrier obtained in step (1), 0.1 g of Mn(NO3)2 (AR, from Sinopharm), and 0.1 g of Fe(NO3)3·9H2O (AR, from Sinopharm) are dissolved in 100 mL of deionized water, ultrasonically treated for 40 min, and then left to stand for 4 h, dried at 105°C for 24 h, heated to 400°C at a rate of 10°C / min under a nitrogen atmosphere, and calcined for 4 h, and then naturally cooled to obtain the catalyst sample.
[0050] Comparative Example 1, The proportioning of the components of the catalyst is adjusted as follows: the active coke carrier content is 80 wt%, the manganese salt content is 10 wt%, and the iron salt content is 10 wt%, and the preparation method comprises the following steps: (1) Active coke pretreatment: columnar active coke particles are crushed and sieved to obtain active coke particles with a size of 40-60 mesh, soaked in a 20% HNO3 solution for 12 h, washed with deionized water until the pH value is 7, and dried to obtain the required active coke carrier; (2) Catalyst preparation by ultrasonic impregnation: 8.0 g of the active coke carrier obtained in step (1), 1.0 g of Mn(NO3)2 (AR, from Sinopharm), and 1.0 g of Fe(NO3)3·9H2O (AR, from Sinopharm) are dissolved in 100 mL of deionized water, ultrasonically treated for 40 min, and then left to stand for 4 h, dried at 105°C for 24 h, heated to 400°C at a rate of 10°C / min under a nitrogen atmosphere, and calcined for 4 h, and then naturally cooled to obtain the catalyst sample.
[0051] Comparative Example 2, The proportioning of the components of the catalyst is adjusted as follows: the active coke carrier content is 70 wt%, the manganese salt content is 15 wt%, and the iron salt content is 15 wt%, and the preparation method comprises the following steps: (1) Active coke pretreatment: columnar active coke particles are crushed and sieved to obtain active coke particles with a size of 40-60 mesh, soaked in a 20% HNO3 solution for 12 h, washed with deionized water until the pH value is 7, and dried to obtain the required active coke carrier; (2) Preparation of catalyst by ultrasonic impregnation method: 7.0 g of the active coke carrier obtained in step (1), 1.5 g of Mn(NO3)2 (National Pharmaceutical, AR), and 1.5 g of Fe(NO3)3·9H2O (National Pharmaceutical, AR) were dissolved in 100 mL of deionized water, and ultrasonic treatment was performed for 40 min. After standing for 4 h, the mixture was dried at 105°C for 24 h, and then calcination was performed at 400°C at a temperature increase rate of 10°C / min under a nitrogen atmosphere for 4 h. After natural cooling, a catalyst sample was obtained.
[0052] Comparative Example 3, On the basis of Example 1, step (1) was not performed, and active coke was not added in step (2). The remaining conditions were unchanged.
[0053] Comparative Example 4, On the basis of Example 1, step (2) was not performed. The remaining conditions were unchanged. The catalyst samples obtained in Examples 1-5 and Comparative Examples 1-4 were subjected to activity tests. 10 mL of 40-60 mesh catalyst was taken each time and placed in a catalyst activity evaluation device for testing. The concentration of the reaction products was detected online by a flue gas analyzer. The typical simulated flue gas conditions were as follows: 500 ppm NO, 500 ppm NH3, 5 vol% O2, N2 as the balance gas, and a gas flow rate of 1,000 ml / min. The simulated flue gas conditions for the sulfur resistance performance test of the catalyst were as follows: 500 ppm NO, 500 ppm NH3, 200 ppm SO2, 5 vol% O2, N2 as the balance gas, and a gas flow rate of 1,000 ml / min. The conversion-temperature curve (the NO Figures 2-10 conversion rate-temperature curve (the NO x conversion rate-temperature curve (the NO
[0054] As can be seen from the conversion-temperature curve (the NO Figure 1 conversion rate-temperature curve (the NO conversion rate-temperature curve (the NO Figure 2 conversion rate-temperature curve (the NO conversion rate-temperature curve (the NO Figure 3It can be seen that the denitrification efficiency of the catalyst sample prepared in Example 3 reached 45.36% at 100℃, 88.63% at 200℃, and 75.32% at 300℃; under the condition of SO2 introduction, the denitrification efficiency decreased by only 2.68% at 200℃, down to 85.95%. Depend on Figure 4 It was found that the denitrification efficiency of the catalyst sample prepared in Example 4 reached 38.77% at 100℃, 78.23% at 200℃, and 69.12% at 300℃; under the condition of SO2 introduction, the denitrification efficiency decreased by 4.17% at 200℃, decreasing to 74.06%. Depend on Figure 5 It can be seen that the denitrification efficiency of the catalyst sample prepared in Example 5 reached 37.64% at 100℃, 73.49% at 200℃, and 66.88% at 300℃; under the condition of SO2 introduction, the denitrification efficiency decreased by 4.48% at 200℃, down to 69.01%.
[0055] Depend on Figure 6 It was found that the denitrification efficiency of the catalyst sample prepared in Comparative Example 1 reached 28.75% at 100℃, 52.66% at 200℃, and 47.08% at 300℃; under SO2 introduction conditions, the denitrification efficiency decreased by 6.29% at 200℃, dropping to 46.37%; Figure 7 It can be seen that the denitrification efficiency of the catalyst sample prepared in Comparative Example 2 reached 24.75% at 100℃, 48.91% at 200℃, and 35.28% at 300℃; under SO2 introduction conditions, the denitrification efficiency decreased by 6.40% at 200℃, down to 42.51%. Comparative Examples 1 and 2 show that reducing the activated coke content significantly reduced the denitrification and sulfur resistance performance of the catalyst. This may be because the reduced activated coke content decreases the support, hindering the dispersion of active components such as manganese oxide and iron oxide, leading to agglomeration of the metal active components, blockage of the activated coke pores, and reduced catalyst performance.
[0056] Depend on Figure 8 It can be seen that the denitrification efficiency of the catalyst sample prepared in Comparative Example 3 reached 23.61% at 100℃, 28.44% at 200℃, and 25.88% at 300℃; under SO2 introduction conditions, the denitrification efficiency decreased by 8.07% at 200℃, dropping to 20.37%. The comparative examples show that without activated coke, the denitrification and sulfur resistance performance of the catalyst containing only metal components decreased significantly. This may be because the absence of activated coke in the catalyst leads to poor dispersion of manganese oxide and iron oxide without a support, and the lack of adsorption activity when activated coke is used as a support results in a decrease in the catalyst's SCR performance.
[0057] Depend onFigure 9 The catalyst sample prepared in Comparative Example 4 has a denitration efficiency of 19.94% at 100°C, 26.97% at 200°C, and 22.58% at 300°C; under the condition of SO2 being introduced, the denitration efficiency at 200°C decreases by 9.20% to 17.77%. As can be seen from the comparative example, the active coke without metal doping still has certain denitration activity, but due to the lack of metal nanoparticles, the active component of the catalyst is reduced, and the performance of the catalyst is significantly lower than that of Example 1.
[0058] The above results show that the low-temperature sulfur-resistant SCR denitration catalyst with active coke as the carrier has excellent low-temperature denitration capacity and sulfur resistance when the content of active coke is 90-98wt%, the content of manganese salt is 1-5wt%, and the content of iron salt is 1-5wt%, and is significantly better than the active coke sample catalyst without metal loading. At the same time, under the condition of introducing SO2 into the complex flue gas, the catalyst within the limited range has higher sulfur resistance than the catalyst outside the limited range.
[0059] The technical solutions and beneficial effects of the present application are described in detail in the above examples, and it should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, supplement and equivalent replacement within the principle range of the present application shall be included in the protection scope of the present application.
[0060] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0061] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.
Claims
1. A method for producing a low-temperature sulfur-resistant SCR de-NOx catalyst using activated coke carriers, characterized by, The method comprises the following steps: Step (1), active coke pretreatment: grinding columnar active coke particles to obtain 40-60 mesh active coke particles, soaking in 20% HNO3 solution for 12 h, washing with deionized water until the pH value is 7, and drying to obtain the active coke carrier; Step (2), preparation of the catalyst: preparing a mixed solution by adding water to manganese salt and iron salt, adding the active coke carrier obtained in step (1) into the mixed solution, and then performing ultrasonic treatment, impregnation, drying, and calcination to obtain a low-temperature sulfur-resistant SCR denitration catalyst with active coke as the carrier after cooling.
2. The process for preparing a low-temperature sulfur-resistant SCR de-NOx catalyst on active coke support according to claim 1, characterized in that, In the step (1), the grinding time of the columnar active coke particles is 20-30 min.
3. The method of producing a low-temperature sulfur-resistant SCR DeNOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the manganese salt is manganese nitrate or manganese sulfate.
4. The process for preparing a low-temperature sulfur-resistant SCR de-NOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the iron salt is ferric nitrate or ferric sulfate.
5. The method of producing a low-temperature sulfur-resistant SCR deNOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the drying temperature is 100-110°C, and the drying time is 10-15 h.
6. The method of producing a low-temperature sulfur-resistant SCR deNOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the ultrasonic temperature is 20-30°C, and the ultrasonic time is 30-60 min.
7. The process for preparing a low-temperature sulfur-resistant SCR de-NOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the heating rate of the calcination is 5-10°C / min.
8. The process for preparing a low-temperature sulfur-resistant SCR de-NOx catalyst on active coke support according to claim 1, characterized in that, In the step (2), the calcination temperature is 300-500°C, and the calcination time is 3-5 h.
9. A low-temperature sulfur-resistant SCR deNOx catalyst with activated coke support, characterized in that, The low-temperature sulfur-resistant SCR denitration catalyst comprises an active coke carrier and manganese oxide and iron oxide supported on the active coke carrier, and is prepared by the preparation method according to any one of claims 1-8.
10. The low temperature sulfur resistant SCR De-NOx catalyst on activated coke support as claimed in claim 9, wherein, In the catalyst, the content of active coke is 90-98 wt%, the content of manganese salt is 1-5 wt%, and the content of iron salt is 1-5 wt%.