Nitrogen Oxides (NOx) are a byproduct produced by high temperature fuel combustion. Nitrogen oxides are produced by a variety of sources ranging from internal combustion automobile engines to industrial equipment, including large-scale industrial boilers. Depending on concentration, the various forms of nitrogen oxide produced by the combustion process range from minor irritants to extremely poisonous.
Because these gases are considered to be relatively harmful (or, at a minimum, undesirable) to humans, it is important that their emission is reduced as much as possible. Although regulations vary by region, nitrogen oxide emissions are both monitored and controlled by the EPA and by state environmental agencies. Selective Catalytic Reduction (SCR) is one common form of nitrogen oxide control and it is widely used in industrial applications as well as the automobile industry.
What is Selective Catalytic Reduction?
Selective Catalytic Reduction is a process by which harmful NOx exhaust gases are converted via chemical reaction into harmless substances before being released to the atmosphere. This process is accomplished by mixing a reductant (a special liquid) into the exhaust stream and allowing a chemical reaction to take place with the aid of a special catalyst. The NOx is converted into nitrogen and water via a reduction reaction. This process is known as a reduction reaction since the NOx is being reduced (it is losing oxygen).
The process was originally developed with ammonia as a reducing agent, but modern systems such as the CataStak SCR systems make use of urea instead. This provides a safer, more environmentally friendly alternative to ammonia. Urea behaves as ammonia in the reaction, allowing for the same efficiency without the difficulties associated with storing and handling ammonia.
Why Use Selective Catalytic Reduction?
Selective Catalytic Reduction is one of the best options available to achieve high levels of NOx reductions. Although more expensive, it can achieve greater overall efficiency than selective non-catalytic reduction as the catalyst allows the unit to operate efficiently within a more reasonable and forgiving temperature. In practice, selective catalytic reduction can achieve reduction efficiencies as high as 90% while still remaining cost effective.
Additionally, selective catalytic reduction systems do not require existing boilers to be altered. The systems operate on the waste gas stream and can be added to existing boilers to meet highly stringent NOx emissions levels without replacing the entire boiler. Non-ammonia based selective catalytic systems are also environmentally friendly and extremely safe, as the urea used as a reductant is not a harmful substance.
My name is Donald Tate and in my blog you'll learn the importance of industrial and manufacturing industries in our country. These facilities make numerous products that we use every day and they're also responsible for creating many jobs. I became interested in industrial and manufacturing plants at a young age because my father worked at a plant downtown. One day he took me to the plant so I could see how the products were made. I thought that was the most interesting thing there ever was and I have been fascinated ever since. Because we depend so much on these industries, I have made it my mission in life to learn all I can about various industrial and manufacturing plants. I hope that after reading my blog, you'll also realize this important and necessary contribution to our society.