Denitration catalyst manufacturer: application methods of low-temperature denitration catalysts
Publishdate：2021-07-16 Views：22
Three application methods of low-temperature denitrification catalysts
Denitration catalyst manufacturer: It is worth noting that the Mn/TiO2 catalyst is recorded as Mn (x)/TiO2, and x is the molar ratio of Mn/Ti, with the following changes.
Due to the strong ability of TiO2 to resist sulfur dioxide poisoning and its poor surface sulfate stability, Mn/TiO2 catalysts will become a focus of research in manganese based denitrification catalysts. In addition, TiO2 also has good electron binding with active components such as MnOx, CeOx, FeOx, and transition metal oxides, ensuring that the prepared catalyst has good denitrification activity. So this type of catalyst has been widely used in China today, especially in industrial production, where the weight of Mn/TiO2 catalyst accounts for 80% to 90% of the weight of denitration catalyst.
In practical use, Mn/TiO2 catalysts also have some problems, mainly manifested in six aspects:
1、 When the catalyst is kept above 450 ℃ for a long time, sintering phenomenon will occur, causing the crystal shape of TiO2 to change over time. Specifically, the particle size increases, the surface area decreases, and the catalyst activity decreases.
2、 The activity of low-temperature denitrification catalysts will also slowly decrease during direct contact with alkali metal ions.
3、 After the diffusion of As2O3 gas in the flue gas, it enters the pores inside the catalyst, where capillary condensation occurs or reacts with the active phase of the catalyst, resulting in a decrease in catalyst activity. This phenomenon is generally not serious in dry slag discharge boilers. It occurs more frequently in liquid slag boilers, due to the process of fly ash recirculation after electrostatic dust removal.
4、 It is the effect of calcium ions on the catalyst. The reaction between CaO and SO3 in fly ash generates CaSO4, which will adsorb onto the surface of the catalyst. This is extremely unfavorable for the diffusion of reactants in the denitrification process towards the surface of the catalyst and into the interior of the catalyst.
5、 It's catalyst blockage. After using the catalyst for a period of time, ammonium salts and small particles of fly ash gradually deposit in its small pores, which will have a serious negative impact on the important process of NOx, NH3, and O2 reaching the active surface of the catalyst, leading to catalyst deactivation. Corrosion and wear of catalysts. The reason is that during long-term use, fly ash sometimes collides with the surface of the catalyst.
Denitration catalyst manufacturer: In the application of low-temperature denitration catalysts, the activity of Mn/TiO2 catalysts should be at a high level, with a small temperature value and a large temperature range, and strong selectivity and resistance to SO2. The performance of halogens, alkali metals, heavy metals, etc. should always be at a high level. On the contrary, the SO2/SO3 conversion rate of the catalyst should be at a low level. In addition, when the surrounding temperature fluctuates greatly, its thermal stability should also be maintained at a high level.
Conclusion:
Denitration catalyst manufacturer: Due to the excellent performance of TiO2, Mn/TiO2 catalyst is currently widely used in low-temperature SCR denitrification technology and one of the relatively mature catalysts in technology. Therefore, low-temperature SCR denitrification has broad development prospects. It has multiple preparation methods, and catalysts prepared by different methods have different performance.
Three application methods of low-temperature denitrification catalysts
Denitration catalyst manufacturer: It is worth noting that the Mn/TiO2 catalyst is recorded as Mn (x)/TiO2, and x is the molar ratio of Mn/Ti, with the following changes.
Due to the strong ability of TiO2 to resist sulfur dioxide poisoning and its poor surface sulfate stability, Mn/TiO2 catalysts will become a focus of research in manganese based denitrification catalysts. In addition, TiO2 also has good electron binding with active components such as MnOx, CeOx, FeOx, and transition metal oxides, ensuring that the prepared catalyst has good denitrification activity. So this type of catalyst has been widely used in China today, especially in industrial production, where the weight of Mn/TiO2 catalyst accounts for 80% to 90% of the weight of denitration catalyst.
In practical use, Mn/TiO2 catalysts also have some problems, mainly manifested in six aspects:
1、 When the catalyst is kept above 450 ℃ for a long time, sintering phenomenon will occur, causing the crystal shape of TiO2 to change over time. Specifically, the particle size increases, the surface area decreases, and the catalyst activity decreases.
2、 The activity of low-temperature denitrification catalysts will also slowly decrease during direct contact with alkali metal ions.
3、 After the diffusion of As2O3 gas in the flue gas, it enters the pores inside the catalyst, where capillary condensation occurs or reacts with the active phase of the catalyst, resulting in a decrease in catalyst activity. This phenomenon is generally not serious in dry slag discharge boilers. It occurs more frequently in liquid slag boilers, due to the process of fly ash recirculation after electrostatic dust removal.
4、 It is the effect of calcium ions on the catalyst. The reaction between CaO and SO3 in fly ash generates CaSO4, which will adsorb onto the surface of the catalyst. This is extremely unfavorable for the diffusion of reactants in the denitrification process towards the surface of the catalyst and into the interior of the catalyst.
5、 It's catalyst blockage. After using the catalyst for a period of time, ammonium salts and small particles of fly ash gradually deposit in its small pores, which will have a serious negative impact on the important process of NOx, NH3, and O2 reaching the active surface of the catalyst, leading to catalyst deactivation. Corrosion and wear of catalysts. The reason is that during long-term use, fly ash sometimes collides with the surface of the catalyst.
Denitration catalyst manufacturer: In the application of low-temperature denitration catalysts, the activity of Mn/TiO2 catalysts should be at a high level, with a small temperature value and a large temperature range, and strong selectivity and resistance to SO2. The performance of halogens, alkali metals, heavy metals, etc. should always be at a high level. On the contrary, the SO2/SO3 conversion rate of the catalyst should be at a low level. In addition, when the surrounding temperature fluctuates greatly, its thermal stability should also be maintained at a high level.
Conclusion:
Denitration catalyst manufacturer: Due to the excellent performance of TiO2, Mn/TiO2 catalyst is currently widely used in low-temperature SCR denitrification technology and one of the relatively mature catalysts in technology. Therefore, low-temperature SCR denitrification has broad development prospects. It has multiple preparation methods, and catalysts prepared by different methods have different performance.
