生物质热解过程中NO、NH3和HCN的释放特性

在氩气气氛下，利用固定床反应器对稻草（DC）、麦杆（MG）和锯末（JM）三种生物质进行热解实验，采用傅里叶变换红外光谱仪（FT-IR）在线检测热解气体产物中的含氮组分，分析各种气相含氮组分的释放规律。实验结果表明，由于锯末中木质素含量较高，锯末热解开始快速释放NO、NH₃和HCN的温度明显高于稻草和麦杆。稻草热解过程中生成的NH₃、HCN和NO量最大。低温下NH₃的生成至少部分与生物质中氨基结构的分解有关，HCN的生成温度较高。不同生物质热解过程中NO、NH₃和HCN释放特性的差异，是由生物质大分子结构不同、灰分含量及成分不同、N含量不同等决定的，以及氮在生物焦、焦油和气相间的分配差异造成的。

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.