Influence of coal properties on emissions of nitrous oxides and nitric oxides

Grey System Theory is applied to study the influence of the coal properties on the emissions of nitric oxides from fluidized bed coal combustion. Grey correlation coefficients for the emissions of nitrous oxides and nitric ox ides in relation to the contents of nitrogen and carbon, fixed carbon, vola tile matter, nitrogen fractions in char, and volatile, and the O/N ratio, f uel ratio, etc., are calculated. A large correlation coefficient of coal pr operty means that the emission of nitrous oxides and nitric oxides is in cl ose relation with the relevant property, in other words, the relevant coal property is the main affecting factor for nitrous oxides and nitric oxides formations. The calculation results show that the N2O emission is determine d mainly by the nitrogen carbon content, fixed carbon, and the nitrogen fra ction in char. While the carbon content, fixed carbon, nitrogen fraction in char mainly influence the NOx emission and nitrogen and hydrogen contents, it suggests that combustion of high rank coal with high nitrogen content i n fluidized bed emits more nitrous oxides and nitric oxides. The O/N and fu el ratios are not important for emissions of nitrous oxides and nitric oxid es compared with other factors. And the results are in agreement with exper imental data.