Abstract:

The release of NO, NH₃ and HCN during chrome shavings pyrolysis was investigated using Fourier transform infrared spectrometer. The effect of the temperature was discussed as time increased. The results showed that the release of NO, NH₃ and HCN during pyrolysis was different from each other. The release of nitrogen-product was relative low in low temperature zone with the domination of NH₃. With increasing temperature, the yields of both NO and HCN increased, especially at 550℃ and the release of HCN over 500 ml ·m^-3 was higher than that of NH₃ exceeded, while the release of NH₃ was kept at 10%-15%. In the high temperature zone, the release of HCN increased rapidly, while the release of NO was relative low. The release of NH₃ was related to the destruction of amino in collagen, such as acid amides and amide band. The HCN was mainly formed by the second splitting decomposition of nitrogen-containing compound in the pyrolyzed char, as well as of the nitrogen-containing heterocyclic compound in pyrolyzed liquid oil. The release of NO was associated to the oxygen-containing function groups such as C=O，C-O/C-O-C, and the ratio of N/O contained in precursor.

Key words: chrome shaving, pyrolysis, NO, NH₃, HCN

摘要：

采用傅里叶变换红外光谱仪对铬革屑热解过程中NO、NH₃以及HCN的释放特性规律进行研究，探讨了随着时间的变化，热解温度对这3种含氮气体释放特性的影响。结果表明，热解过程中NO、NH₃以及HCN的释放随温度的升高呈现不同的规律。在热解温度较低的情况下含N气体的释放较少，其中NH₃的释放占主导。随着温度的升高，NO、HCN的释放量上升，尤其在550℃，HCN的释放率反超NH₃，释放的浓度达到500 ml·m^-3以上，NH₃的释放率维持在10%~15%。高温区HCN的释放存在迅速升高的过程，NO的释放量相对较少。NH₃的释放主要与胶原蛋白中氨基结构的破坏有关，如酰胺及酰胺带结构，而HCN主要来自于焦含氮结构的二次裂解，以及热解液体中含氮杂环物质的分解。NO的释放主要与C=O，C-O/C-O-C等含氧基团的变化以及原料中的N/O比例有关。

关键词: 铬革屑, 热解, NO, NH₃, HCN