ABSTRACT
Most of nitrogen oxides in the ambient air come from combustion. Formation of nitrogen oxides in combustion cannot be avoided, but can be reduced. Nitrogen oxides in flue gases can also be removed from back-end treatment. This chapter deals with an introduction on the family of nitrogen oxides and their sources and emissions. It describes types of flames, combustion temperature, and stationary combustion systems. The chapter discusses Formation mechanisms of three types of NOx i.e., thermal, fuel, and prompt. It also describes general approaches to reduce NOx emissions Reduction of NOx formation can be achieved through combustion modifications and fuel switching. The chapter presents two back-end treatment technologies i.e., selective non-catalytic reduction and selective catalytic reduction to reduce NOx in the flue gas to nitrogen molecules before discharge. It also presents process selection and design calculations with regards to control of nitrogen oxides emissions.
