Highly efficient combustion with low excess air in a modern energy from-waste (EfW) plant

The effect of low excess air and high adiabatic combustion temperatures on CO and NOx formation has been investigated on a commercially operated energy-from-waste plant. With optimal combination of low O-2 levels and stable combustion control, uncontrolled NOx levels could be lowered to 100-150 mg/Nm(3) (dry, at 11% O-2) while keeping CO emissions at low levels. Even at adiabatic temperatures above 1400 degrees C thermal NOx hardly contributed to the total NOx emissions in a grate-fired EfW plant. An advanced combustion control system allowed continuous operation with very little excess air (lambda < 1.2) while keeping CO and NOx at levels well below the legal emission limits. (C) 2017 Elsevier Ltd. All rights reserved.