The application of low NOx burners is not always followed by a reduction of NOx emissions.

The low NOx burners are useful for reducing the flame temperature and thus reducing thermal and (to some extent) fuel derived NOx.

Low NOX burners are applicable to rotary kilns and to annular shaft kilns presenting conditions of high primary air.

PFRKs and other shaft kilns have flameless combustion, thus rendering low NOX burners not applicable to this kiln type