The effectiveness of reburning using rice husk as secondary fuel for NOX reduction in a furnace

ABSTRACT The aim of the present work was to evaluate the effectiveness of the reburning process using biomass (rice husk) as reburn fuel in a large-scale laboratory furnace. For comparison purposes, tests were also conducted using natural gas and ethylene as reburn fuels. The paper reports new data for flue-gas emissions for a wide range of experimental conditions which quantify the effects of the reburn fuel fraction (energy basis), residence time in the reburning zone, and initial NO x concentration for the three secondary fuels on NO x reduction from the present combustor. The results show that at reburn zone residence times of about 0.7 s the reburning performance of the rice husk (1) is comparable to that of the natural gas reburning at high reburn fuel fractions, with almost 60% NO x reduction achievable at reburn fuel fractions of 25 and 30%, and (2) approaches those of the natural gas and ethylene at high initial NO x concentrations, with nearly 60% NO x reduction attainable at initial NO x concen...