Research on the effect of CO2 and H2O on NO reduction of biomass char by the equivalent characteristic spectrum method via an on-line mass spectrometer

Despite extensive experimental studies on NO reduction by biomass char, the impact of high concentrations of CO2 and H2O on the NO-char reaction remains insufficiently understood. This study investigates the effects of CO2, H2O, and CO2+H2O atmospheres on NO reduction by biomass char in a micro-fluidized bed (MFB). Experiments were conducted at 900 °C, with CO2 concentrations ranging from 20 % to 80 % and H2O concentrations from 10 % to 40 %. The results show that increasing concentrations of CO2 and H2O accelerate the NO reduction rate. However, under high CO2 and H2O concentrations, both the maximum NO reduction efficiency and the mass consumption of nitrogen decrease. In a CO2 atmosphere, nearly all nitrogen from NO converts to N2, but this conversion efficiency declines in the presence of H2O. When both CO2 and H2O are present, H2O predominantly governs the NO consumption rate. Additionally, the apparent activation energy for NO reduction is higher in an H2O atmosphere compared to a CO2 atmosphere at similar concentrations.