Kinetic Analysis of NO Reduction by Biomass Pyrolysis Gas

Reburning for NO reduction by simulated biomass pyrolysis gas (H₂/CO/CH₄/C₂H₂/C₂H₄) has been studied by using detailed improved kinetic modeling. A reaction set including 66 chemical species and 448 elementary gas-phase reactions was applied. The improved mechanism can reasonably simulate the evolution of the mole fractions of NO and HCN in Dagaut´s experiments. According to this study, HCCO, C and CH_i(i=l,2,3) radicals have important effect on NO reduction. The effect of CO on NO reduction is inferior to that of simple hydrocarbons including CH₄, C₂H₂ and C₂H₄, etc, and CO mostly converts into CO₂. H₂ plays an important role in accelerating reaction process. NO reduction by biomass pyrolysis gas reburning is primarily through the following sequence: CH_4rarrCH₃rarrCH₂(s)rarrCH₂rarrCHrarrC; C₂H₄rarrCH₃,C₂H₃; C₂H₃rarrC₂H₂rarrCH₂,HCCO; HCCOrarrCH₂(s); C+NOrarrCNrarrNCO; CH_i(i=1,2,3)+NOrarrHCNrarrNCO,CN; HCCO+NOrarrHCNOrarrHCN ; NCOrarrHNCO,NH,N₂O ; HNCOrarrNH₂rarrNH,NNH ; NH,NH₂+NOrarrNNHrarrN₂; NH₂+NOrarrN₂ ; N₂OrarrN₂.