Combustion behavior and pollutant emission characteristics of RDF (refuse derived fuel) and sawdust in a vortexing fluidized bed combustor

This paper presents the results obtained from RDF and sawdust combustion in a pilot scale vortexing fluidized bed combustor (VFBC). Flue gas recirculation (FGR) combustion mode was employed. The effects of operating parameters such as bed temperature, excess oxygen ratio, and in-bed stoichiometric oxygen ratio on the combustion behavior and pollutant emission characteristics were investigated. The experimental results show the different combustion characteristics with different fuels in the VFBC. For sawdust combustion, CO emission decreases with bed temperature, excess oxygen ratio, and in-bed stoichiometric oxygen ratio. The NOx emission shows an inverse trend. Combustion using sawdust as the fuel has difficulty meeting the CO emission regulation requirement. The CO and NOx emissions of RDF combustion show a similar trend as that of sawdust; however RDF combustion can significantly decrease the CO emission due to its distinct pellet structure and burning pattern.