Final answer:
Nitrogen oxides in flue gas can be significantly reduced by using a scrubber system that involves scrubbing the flue gas with lime, converting harmful emissions into less harmful compounds before release.
Step-by-step explanation:
The nitrogen oxides in flue gas may be reduced by scrubbing the flue gas with lime. In power plants, a scrubber is often used to remove sulfur dioxide (SO2) and nitrogen oxides from the emissions before they are released into the atmosphere. This system introduces calcium carbonate (lime) into the combustion chamber, which then decomposes into calcium oxide and carbon dioxide. The calcium oxide reacts with sulfur dioxide to form calcium sulfite. A suspension of lime can also remove other pollutants and unreacted sulfur dioxide by producing a slurry that captures these substances effectively, thus reducing their presence in flue gas.