Coal Characterisation for NOx Prediction in Air-Staged Combustion of Pulverised Coals
FUEL, Vol 84(17) (2005), pp. 2190-2195
Posted: 24 Jan 2020
Date Written: 2005
A series of world-traded coal samples has been tested using the Imperial College high temperature wire mesh apparatus (HTWM) in order to assess the relationship between high temperature (16008C) char nitrogen content and NOx formation in Hemweg Power Station (in the Netherlands) using deep furnace air staging. A linear relationship between high temperature char nitrogen and NOx formation has been confirmed. These results suggest that high temperature char N content is the main factor limiting NOx emissions with deep air-staged combustion. Char N and (hence apparently deep air-staged NOx) can be predicted with an accuracy of approximately G20% for most coals from the coal proximate and ultimate analysis—but this might not be sufficient for stations operating close to their emission limits. Measuring high temperature char N directly reduces the likely uncertainty in deep air-staged NOx emissions for coals (and most blends) to approximately G10%. Its use should be considered on a routine basis for coal selection on plants employing this technology.
Keywords: Overfire air; NOx prediction; High temperature; Devolatilisation
JEL Classification: M41
Suggested Citation: Suggested Citation