The characteristics of biomass torrefaction and nitrogen oxide emission during co-firing with coal
Abstract Torrefaction can effectively improve biomass physicochemical properties and mitigate adverse effects during coal co-firing, while nitrogen migration differences between woody and herbaceous biomass during torrefaction remain unclear. This work investigates torrefaction effects on woody Salix psammophila (SP) and herbaceous Arundo donax (AD), focusing on NOx emission and fuel nitrogen migration during co-firing. The results show that torrefaction temperature significantly affects the product distribution. Considering low heating value (LHV) and energy yield, 270 °C is the optimal torrefaction temperature. Under N2 atmosphere, the N-A functional groups in SP mainly transform into N-5 and tar-N, and the oxidative atmosphere inhibits this transformation process. In contrast, under N2 atmosphere, the N-A functional groups in AD convert into tar-N and N-Q, and the oxidative atmosphere promotes the formation of N-Q. The co-firing mode has a significant impact on NOx emissions du...