微波加热技术在催化NOx脱除中的应用

Application of microwave heating technology in catalytic removal of NOx

综述了空气中氮氧化物的类型、危害及脱除方法。空气中氮氧化物主要为NO、N2O和NO2,化石燃料和植物体的燃烧以及土壤和动物排泄物中含氮化合物的转化是其主要来源,NOx是酸雨和雾霾天气形成的主要原因之一,严重影响人类健康。选择性催化还原技术通过氨等还原剂和催化剂的共同作用将NOx还原成N2和H2O,选择性非催化还原技术利用氨等还原剂在高温环境下的还原能力实现NOx的脱除。传统NOx脱除技术存在脱除效率不高和易产生二次污染的缺点。微波放电技术利用微波放电产生高能电子使NOx直接分解生成N2,微波碳热还原技术利用微波辐照活性炭的热效应可以显著提高炭对NOx的脱除能力,对NO脱除率高于96%。以微波为基础的脱硝技术在工业催化脱硝领域中的应用研究表明,结合催化剂、微波作用等手段实现工业高效脱除氮氧化物是一种较为理想的实现方式,应用前景良好。

The types, harm and removal methods of nitrogen oxides in the air were summarized. Nitrogen oxides mainly consisted of NO, N2O and NO2, which were produced by the combustion of fossil fuel and plants, and the conversion of nitrogen compounds in animal waste and the soil. NOx was one of major formation causes of acid rain and the smog, which had a serious influence on the health of human beings. Selective catalytic reduction technology based on the interaction of reducing agents such as ammonia and catalysts could make NOx into N2 and H2O, while non-selective catalytic reduction technology achieved the removal of NOx with reducing agents such as ammonia at high temperature. However, the traditional techniques for removing NOx had shortcomings of low removal efficiency and easy production of secondary pollution. Microwave discharge technology could directly decompose NOx to N2 by producing high-energy electrons, and microwave carbon thermal reduction technology could significantly improve NOx removal ability by utilizeing thermal effects of microwave irradiation on active charcoal. The removal efficiency of NO was more than 96%. The application researches on microwave relating to de-NOx technology in commercial catalytic denitrification field showed that the combination of catalysts, microwave and other techniques was an ideal way of removing the nitrogen oxides, which had a good application prospect.