Use of urea at coal fired power plants?

Answer 1

Here is a novice explanation. Urea is used as a reactionary agent, reductant, in both Selective Catalyst Reduction (SCR) and Selective Non-Catalyst Reduction systems (SNCR) in order to reduce NO2 emissions and convert them into CO2 and water. Urea in an SCR is sprayed into the Flue Gasses before it flows through the catalyst, carbon blocks with many holes. In an SNCR the Urea is sprayed directly into the Fire Box, or Furnace in a place as to be at a certain temperature in order to achieve the same result without the catalytic blocks and is then far less expensive to install, but much more complex to control, as reaction temperatures and distribution amounts are key in the SNCR in order for it to work. In place of Urea, Ammonia may also be used.

Answer 2

Urea can be used in Selective Catalytic Reduction (SCR) systems at coal fired power plants to reduce nitrogen oxide (NOx) emissions. Urea is injected into the flue gas stream where it reacts with NOx to form harmless nitrogen and water vapor, helping to meet emissions regulations. The SCR system is an effective way to reduce NOx emissions and improve air quality from coal fired power plants.