Formation of NO, NH₃ and HCN during pyrolysis of biomass

Rice straw (DC), wheat straw (MG) and sawdust (JM) were pyrolyzed in a fixed-bed reactor under argon atmosphere at 10℃/min. The nitrogenous components in the product gases were analyzed by Fourier transform infrared spectrometer (FT-IR). The results show that the releasing temperature of NH₃, HCN and NO of JM is apparently higher than that of DC and MG, which is due to the higher content of lignin in JM. DC releases more NH₃, HCN and NO than MG and JM during pyrolysis. The NH₃ formed at lower temperature is at least partly related to the thermal decomposition of the amino structures. The formation of HCN may occur at a higher temperature. The nitrogen release during the biomass pyrolysis depends on the macromolecular structure, ash content, nitrogen content, and nitrogen distribution among char, tar and gas.