Nitrogen distribution analysis during the devolatilization process of various feedstocks using TG-DTG-MS analysis

The fuel-NOx emissions during the conversion of carbon-based feedstock into energy and chemicals are on a global level in focus last decades due to environmental issues. The emission of nitrogen oxides is recognized among the other pollutants, as one of the key environmental problems related to energy production by various types of feedstocks. In this paper, the effect of fuel-based nitrogen delivery on the development of NOx precursors (HCN and NH3) during the devolatilization process of properly selected samples (coal, sawdust, wheat straw, and ground coffee waste) has been examined. TG-DTG thermal analysis techniques, coupled with mass spectrometry (MS) were used for the assessment of nitrogen distribution for HCN and NH3 gases, as intermediate species during feedstocks devolatilization, which directly influences the NOx emission during thermochemical conversion processes (pyrolysis and combustion). The mass balance of nitrogen together with performed EGA (evolved gas analysis), and the distribution of nitrogen between volatiles and formed char were also determined. The obtained data for investigated samples could be exploited for further thermochemical process optimization, in regard to NOx emissions. The presented results could be used as the experimentally determined input parameters for the mathematical modeling of indicated processes, and with further analysis can be transferred to large-scale industrial plant applications.