Title:
Experimental Study on the Fixed-Bed Combustion Process of Coal and Biomass and the In-Bed Formation of Nitric Oxide
Author(s):
Deng, R., Wang, L., Zhang, R., Liao, Z., Luo, Y.
Document(s):
Paper
Poster
Abstract:
In fixed-bed combustion system, the formation behavior of NO is complicated due to the unique in-bed combustion processes. The fuel bed would be divided into several distinctive regions by the propagating ignition front, and the formation and reduction of NO would occur corresponding to the in-bed conversion regions. In this work, a biomass (wood pellet) and a coal (Shenmu coal) are selected as representative fuels, and their NO formation behaviors during fixed-bed combustion process are investigated both above and inside the fuel bed. Around the ignition front, volatile would be rapidly released and oxidized. The peak value of NO concentration at the ignition front confirmed that NO would also be rapidly formed in this region. Above the ignition front lies a char layer forming a reductive zone. The NO concentration above the fuel bed was significantly lower than that at the ignition front, which indicated that NO released form the ignition front could be effectively reduced when passing through the char layer. Therefore, the overall NO release during fixed-bed combustion should be regarded as the combined effect of formation at the ignition front and reduction by the char layer. Biomass and coal exhibited some distinctive NO formation behaviors due to their different fuel properties. During biomass combustion, most fuel-N are released as volatile and oxidized at the ignition front, while more fuel nitrogen is retained in char residue for coal. Consequently, both the NO concentration at the ignition front and the peak value of NO concentration above the fuel bed are higher for wood pellet than those of coal. Coal would release less NO at the ignition front and accumulate more char above the ignition front, and therefore the NO concentration above the fuel bed decreased significantly faster than that of wood pellet after reaching the peak value.
Keywords:
biomass, coal, combustion, fixed bed, NO
Topic:
Biomass Conversion for Bioenergy
Subtopic:
Biomass and Bioliquids Combustion for Small and Medium Scale Applications
Event:
29th European Biomass Conference and Exhibition
Session:
2BV.6.2
Pages:
554 - 560
ISBN:
978-88-89407-21-9
Paper DOI:
10.5071/29thEUBCE2021-2BV.6.2
Price:
FREE
