Ammonia desorption from fly ash

Abstract

The main source of ammonia in ash are residues from an unreacted NH3 from the denitrification process, either from SCR or SNCR systems. The paper discusses the standards of NH3 content in fly ash and presents the most commonly used methods of removing excess ammonia from fly ash. In the next part of the work the results of laboratory tests on NH3 desorption are presented. Desorption was performed on samples of fly ash taken from the electrostatic precipitator of real PC boiler. Removal of NH3 from the ash was carried out in a heating chamber at 130°C and 150°C and detected by an analyser equipped with a NDIR sensor. Additionally, at the temperature of 130°C, the NDIR and analytical methods were compared (in accordance with the BN-750541-05 procedure) and the measurement uncertainty of both methods was estimated.