CH_4-SCR脱硝催化剂研究进展

Research progress of CH_4-SCR denitration catalyst

氮氧化物是主要的大气污染物,可产生酸雨、光化学烟雾,破坏大气环境,危害人体健康。NH3-SCR脱硝技术在工业上NOx的减排中得到广泛应用,但NH3在储存、运输和使用中存在泄漏等二次污染,寻找新型还原剂成为研究热点。CH4廉价易得,是一种良好的还原剂,开发甲烷选择性催化还原(CH4-SCR)氮氧化物催化剂受到国内外学者关注。概述了贵金属类、氧化物类、分子筛类等催化剂在CH4-SCR脱硝中的催化性能。在贵金属催化剂中分子筛负载Pd催化剂和Ag/Al2O3催化剂在CH4-SCR脱硝中表现出较好的催化性能;在氧化物催化剂中Cr改性的In/WO3/Zr O2催化剂活性较好,载体的酸化处理可以改善催化剂性能;钴修饰的分子筛催化剂表现出优良的催化性能;在CH4-SCR脱硝反应中提高NO转化率的关键是提高CH4选择性。

Nitrogen is one of the main air pollutants,which will lead to acid rain and photochemical smog,damage the atmosphere environment and harm human health. Although CH4-SCR denitration technology is widely applied in control of NO emission in commercial operation,the leakage and secondary pollution of NH3 exist in storage,transportation and utilization. Therefore,the development of new reductant has become the R D hot spot. As CH4,which is cheap and available,is a good reductant,the development of methaneselective catalytic reduction（ CH4-SCR） catalyst for the selective catalytic reduction of NOxhas attracted increased attention of scholars both at home and abroad. The catalytic properties of precious metal catalysts,oxide catalysts,molecular sieve catalysts,etc in selective catalytic reduction of NOxwith methane are described.In precious metal catalysts,the molecular sieve catalysts loaded with Pd and Ag / Al2O3 catalysts exhibit excellent catalytic performance in CH4-SCR denitrtration of NOx. In oxide catalyst,the In / WO3/ Zr O2 catalysts modified by Cr show favourable catalytic performances. The acid treatment of carrier can improve the performances of catalysts. Molecular sieve catalysts modified by Cobalt show excellent catalytic performances. To improve the selectivity of CH4 is critical for the improvement of conversion of NO in CH4-SCR denitration reaction.