WHAT YOU NEED TO KNOW ABOUT SELECTIVE CATALYTIC REDUCTION OF NOX

Selective catalytic reduction of NOx is widely applied in industries that use fossil fuels for power production. The system is also applied in industrial boilers, utility boilers and waste boilers where production of NOx is very high. NOx gases are known for their adverse effects on human and plant life. They are part of the green gases that have led to global warming and changed weather patterns. Gases such as nitrogen dioxide are known for their foul smell and negative effect on visibility. Catalytic reduction systems are meant to reduce these gases by at least 75% hence ensure environmental conservation and sustainability.

When talking of Selective catalytic reduction of NOx, two main gases are involved. These are NOx gases and ammonia. Ammonia is used as a catalyst hence it is not exhausted during the process. There are two main reactions that occur during the process. The first reaction occurs between ammonia and nitrogen oxide while the second reaction occurs between ammonia and nitrogen dioxide. In other cases, the emissions may also have a considerable amount of oxygen gas. In such a case, the gas is involved in the reaction to form H2O and nitrogen gas. The other primary reactions also result in formation of H2O and N2 gas.

Selective catalytic reduction of NOx was initially common in boilers used in industries. However, this technology is recently used in diesel engines for selective reduction of NOx gases. There are a couple of challenges that have been experienced in diesel engines since they operate on high temperatures. The fact that they produce particulate matter makes the situation even worse since clogging of reaction sites is bound to happen. However, some improvements such as use of strong catalytic ceramics and particulate filtering systems have been made. The systems ensure that all the emissions are filtered before they are directed to the catalytic chamber for reduction.

During the selective catalytic reduction of NOx in boilers and diesel engines, some undesired reactions between ammonia and other gases may occur. Such cases include the reaction of ammonia, NO2 and water which leads to the production of ammonium nitrate. Other cases include the reaction of ammonia with H2SO4 produced from the reaction between SO3 and water. Such reactions may pose a negative impact on the catalyst hence making the systems less efficient. However, technologists are coming up with various improvements such as temperature control systems to ensure that such occurrences are reduced. This makes selective catalytic of NOx one of the best methods for reducing NOx emissions.