In actual operation and use, although the surface of the denitrification catalyst is often kept clean, the internal micropores are blocked from time to time. This problem troubles many companies and directly affects the overall efficiency and service life of the denitrification system. So, what exactly causes this situation? How to solve these problems to ensure the long-term and efficient operation of the denitrification catalyst? This article will analyze this in detail, analyze the causes of the problem from the perspectives of dust particle penetration, sulfate deposition, and fly ash accumulation, and propose optimization solutions to deal with blockage, helping companies to extend the life of the catalyst and improve the efficiency of the denitrification system.

 

Seven reasons for blockage of micropores in denitrification catalysts

1. Penetration of dust and particles: invisible hidden dangers During the denitrification reaction, although the external surface of the catalyst may remain clean, some tiny dust and particles can penetrate the surface and enter the microporous structure inside the catalyst. These fine particles are difficult to remove in time due to their small size. Over time, they will gradually accumulate inside the micropores, resulting in a reduction in the effective surface area of ​​the catalyst, thereby affecting the efficiency of the denitrification reaction. Compared with the surface, the inside of the micropores is more difficult to clean, so this type of blockage is often difficult to detect and becomes a potential hidden danger.

 

2. Sulfate deposition: a silent killer In the process of using sulfur-containing fuels, sulfur dioxide (SO₂) generated by combustion reacts with other substances in the catalyst to form sulfates. These sulfates often deposit deep into the micropores of the catalyst, causing the micropores to gradually clog. Due to the scouring of airflow and high temperatures, the external surface is usually not easy to deposit, so the catalyst may still look intact, but the inside of the micropores has been slowly eroded by sulfates. This silent clogging process will gradually reduce the activity of the catalyst and the overall denitrification effect.

 

3. Fly ash accumulation: silent accumulation In industrial environments, especially coal-fired power plants, the air often carries a large amount of fly ash and ultrafine particles. Due to their small size, these particles can easily penetrate the pores on the surface of the catalyst, enter the microporous structure and gradually settle down. This phenomenon does not immediately show a problem, but over time, the accumulation of fly ash in the micropores will gradually reduce the reaction area of ​​the catalyst, thereby reducing the denitrification efficiency. At this point, the surface cleanliness does not reflect the true situation inside the catalyst, making the problem more difficult to detect.

 

4. Catalyst aging: an inevitable natural law During the long-term use of the catalyst, the microporous structure will inevitably age, the pore size will gradually shrink, and the internal space will become smaller. This aging phenomenon not only makes it easier for particulate matter to accumulate in the micropores, but also leads to increased micropore blockage. Even if there is no obvious blockage on the external surface, the internal structural changes caused by aging will affect the overall performance of the catalyst. This requires us to regularly monitor the condition of the catalyst to avoid the long-term impact of aging problems on denitrification efficiency.

5. Accumulation of incomplete reaction byproducts: unexpected products In the denitrification reaction, ammonia (NH₃) reacts with nitrogen oxides (NOx) as a reducing agent to generate nitrogen (N₂) and water vapor. However, under certain conditions, this reaction may not be complete, producing some byproducts, such as ammonium salts (NH₄HSO₄). These byproducts are easily deposited in the micropores of the catalyst, causing pore blockage and affecting the activity of the catalyst. Especially when the reaction conditions are not ideal, the accumulation of by-products may be more serious, further affecting the performance of the catalyst. At this time, although the appearance of the catalyst may not change much, the internal micropores have been quietly occupied by by-products.

 

6. The influence of water vapor and temperature fluctuations: environmental factors that cannot be ignored During the operation of the denitrification system, if there is excessive water vapor or the operating temperature fluctuates frequently, the water vapor may combine with the reaction gas to form crystals or other solid substances in the micropores of the catalyst. These crystals or solid substances cannot be easily discharged, gradually blocking the micropores and affecting the activity of the catalyst. Especially in an environment with unstable temperature, frequent changes in water vapor and temperature will accelerate the formation of blockage. Although the external surface is still smooth, the internal micropores have been seriously affected, and the denitrification reaction efficiency is greatly reduced.

 

7. Uneven cleaning effect: potential cleaning blind spot Most denitrification systems are equipped with cleaning devices to prevent dust particles from depositing. However, if the cleaning system is not designed properly or the cleaning effect is uneven, the catalyst surface may remain relatively clean, but the dust accumulation in the internal micropores is not completely removed. This situation will cause the micropore blockage problem to gradually intensify, affecting the overall reaction efficiency of the catalyst. Long-term neglect of the uniformity of the cleaning effect will greatly shorten the service life of the catalyst.

 

How to solve the problem of micropore blockage?
Now that we understand the main reasons for micropore blockage, how can we effectively solve this problem? Here are a few suggestions to help companies better maintain the performance of catalyseurs de dénitrification in daily operations:

1. Regular cleaning and maintenance Clean and maintain the catalyst regularly, especially pay attention to the cleaning effect of the internal micropores, ensure that the cleaning device can cover all parts of the catalyst, and avoid the problem of incomplete local cleaning.

2. Monitor reaction conditions Real-time monitoring of the operating conditions of the denitrification system, especially temperature and water vapor content, to ensure that the system operates under optimal conditions and reduce the generation and deposition of by-products.

3. Optimize fuel and reaction conditions Choose low-sulfur fuel as much as possible to reduce sulfate deposition. At the same time, optimize the reaction conditions of ammonia and NOx to avoid by-product problems caused by incomplete reactions.

4. Catalyst regeneration For catalysts that become clogged after a period of use, you can consider treating them through regeneration technology to restore the microporous structure and activity of the catalyst and extend its service life.

5. Regularly check the status of the catalyst. Use special testing equipment to regularly check the status of the catalyst, especially the permeability of the micropores. Through scientific monitoring methods, potential problems can be discovered and solved in a timely manner to avoid blockage from affecting system performance.

 

Conclusion
Micropore blockage is a common problem in the long-term use of denitrification catalysts. Although the surface may remain clean, internal blockage is gradually forming. By understanding the influence of factors such as dust, fly ash, and sulfate deposition, and taking effective cleaning, monitoring and optimization measures, enterprises can greatly improve the use efficiency of denitrification catalysts and ensure the long-term stable operation of the system. Smart management and scientific maintenance will help enterprises to stay steady on the road of environmental protection.