燃煤流化床中CaO催化还原N2O机理研究

应用热失重与傅立叶红外光谱联用仪研究了CaO在流化床燃煤气氛下对N2O的分解还原机理。实验结果表明CaO的催化作用使N2O浓度降低的初始温度由1150K降低至1050K;在CO的作用下N2O降低的初始温度由1050K降低至1000K。对实际流化床燃煤过程中CaO的作用分析认为,CaO对N2O的催化分解能力与煤的含硫量密切相关;它与HCN的气固反应减少了产生N2O的来源以及CaO对N2O的多相催化反应是降低N2O的主要原因之一。

Reduction of N2O over CaO under Fluidized Bed Combustion of Coal

The combination of TG(thermogravimetric) analysis with Fourier transform infrared(FTIR) spectroscopy was used to analyze the mechanism of decomposition and reduction of N 2O over CaO under fluidized bed combustion of coal. CaO is an effective catalyst for reduction of N 2O. The initial decomposition temperature of N 2O is reduced to 1?050?K from 1?150?K in the presence of CaO, while the temperature is 1?000?K together with CO. The catalytic ability of CaO on N 2O is dependent on SO 2 concentration in the fluidized bed boilers. CaO may react with HCN forming CaCN 2 to decrease the oxidation of HCN to N 2O. It is believed that heterogeneous catalytic decomposition of N 2O over CaO plays the most important role in reducing the emission of N 2O in fluidized bed combustion of coal.