ADVANTAGES AND LIMITATIONS OF SELECTIVE CATALYTIC REDUCTION

Selective catalytic reduction is a process through which nitrogen oxide harmful emissions are converted into nitrogen and water. The process involves injection of ammonia air or steam into channels containing nitrogen oxide gases. This allows them to mix properly before they are passed through a catalytic chamber where nitrogen oxide is converted. The whole reduction process does not alter the composition of the catalyst hence it can be used over and over again. Some industries make use of urea as the catalyst and end up producing CO2 as a byproduct. The SCR systems are used in various industrial applications such as industrial boilers, gas turbines, ship diesel engines, power plants and locomotives.

Most industries running on diesel power produce lots of nitrogen oxide gas. The government has made it a requirement for such firms to incorporate selective catalytic reduction systems so as to reduce on pollution. The SCR systems can reduce the amount of nitrogen oxide released into the atmosphere by up to 90 percent. Other firms have recorded a 65 percent reduction during their heavy load operation time. Such industries are working on their systems to ensure that this percentage is improved for minimal pollution to occur. Various limitation lead to the occurrence of 10-35 percent error in these systems.

One of the major limitations of the selective catalytic reaction systems is that contamination can easily occur due to use of wrong construction materials. Contamination basically involves ions passing through to the porous part of the SCR. Therefore, it is important to ensure that the correct material is used for construction. Manufactures also face a major challenge synchronizing the rate of machine operation with the SCR. The two have to be synced through theoretical simulation or practically on the firm through data logging. Minor errors likely to occur during the process may lead to failure of the system.

Other harmful gases such as ammonium bisulfate and ammonium sulfate are also produced when fuels are burnt. This is due to the existence of small amounts of sulfur in the fuel. Such gases have to be considered during the incorporation of selective catalytic reduction systems hence making the process hectic. The requirement by law for heavy industries to use SCR has led to an increased attention to the system. Scientists are coming up with various improvements to ensure that the system can deal with the listed limitations effectively. They also aim at reducing the release of nitrogen oxide gas to the air by a greater percentage.