Posted by NINGBO INNO PHARMCHEM CO.,LTD.

Selective Catalytic Reduction (SCR) catalysts are engineered for durability, but their performance and lifespan can be significantly impacted by various operational factors. Understanding the mechanisms of catalyst deactivation, such as poisoning and fouling, is crucial for implementing effective maintenance strategies. For industrial operators, maximizing the lifespan of SCR catalysts not only ensures consistent NOx reduction efficiency but also leads to significant cost savings. If you are looking to buy SCR catalysts, it’s equally important to consider the supplier’s guidance on maintenance and longevity.

Catalyst Poisoning occurs when specific chemical species present in the flue gas irreversibly bind to the active sites of the catalyst, rendering them inactive. Common poisons include alkali metals (like sodium and potassium), alkaline earth metals, heavy metals (such as cadmium, mercury, lead), phosphorus, and arsenic. These elements can originate from the combustion of various fuels, particularly coal. For example, phosphorus can react with active sites, reducing catalytic activity, while heavy metals can block active sites or catalyze unwanted side reactions. When selecting where to buy SCR catalysts, understanding the catalyst’s resistance to known poisons in your specific flue gas is paramount.

Fouling and Clogging, on the other hand, involve the physical accumulation of inert materials on the catalyst surface or within its pores. Soot, fly ash, and even the by-products of the SCR reaction, like ammonium sulfate and ammonium bisulfate (formed from SO2 and ammonia), can block the catalyst channels. This blockage increases the back-pressure in the system, reduces the effective surface area for the reaction, and can lead to channeling and uneven gas distribution, thereby decreasing NOx removal efficiency. Regular cleaning, such as using soot blowers or ultrasonic horns, can help mitigate fouling.

To ensure peak performance and extend the lifespan of SCR catalysts, several maintenance strategies are recommended. Firstly, precise control over the injection of the reducing agent (ammonia or urea) is vital to minimize ammonia slip and prevent the formation of excessive ammonium sulfate. Secondly, regular monitoring of flue gas composition and temperature is essential to identify potential issues early. Thirdly, as mentioned, implementing cleaning protocols for soot and ash buildup can prevent fouling. For industries that use fuels with high levels of known poisons, selecting catalysts specifically designed for improved poison resistance, or implementing upstream purification steps for the flue gas, can be highly beneficial.

NINGBO INNO PHARMCHEM CO.,LTD. is committed to providing not just high-quality SCR catalysts, but also the knowledge to maintain them. By adopting proactive maintenance and understanding the causes of deactivation, operators can significantly enhance the service life and economic viability of their SCR systems.