IDENTIFICATION OF PRECURSORS FOR NO_x FORMATION IN WASTE COMBUSTION BY MEANS OF TG-FTIR

摘要

The detection of reactive NO_x precursors from municipal solid waste incineration requires the analysis in the mainly unchanged gas phase. Although HCN and HNCO are supposed to play a key role in NO_x formation, their reactivity restrains quantification via condensation and conventional analysis (e.g. GC-MS). Thus, a high-sophisticated online gas analysis method like coupled Thermogravimetry - Fourier Transform Infrared Spectroscopy (TG-FTIR) has to be used. By means of improved TG-FTIR, we succeeded in detecting HCN and HNCO in complex combustion gases of various high-protein waste fractions (HPW). Tracing the release in air by temperature variation up to 900℃, HCN is observed in two maxima at about 300 and 500℃; major HNCO release occurs at 300℃, with a small share released at 500℃ as well. Quantification proved HCN to be a major N-product of the combustion of high-protein waste: 5 -15% of the total N content of all investigated HPWs is released as HCN. The release in inert atmosphere was found to be significantly lower (typically 5% of total N).