负载Mn-Fe及硫酸酸化联合作用对合成(Ce,La)CO_(3)F的NH_(3)-SCR脱硝性能影响

Effect of Combined Mn-Fe Loading and Sulphuric Acid Acidification on NH_(3)-SCR Denitration Performance of Synthetic(Ce,La)CO_(3)F

以白云鄂博氟碳铈矿为研究对象,按其Ce/La质量比利用水热法合成(Ce,La)CO_(3)F晶粒,并对其NH_(3)-SCR脱硝性能进行研究。结果表明,投加过量NaHCO_(3)合成的(Ce,La)CO_(3)F催化效果更好。合成(Ce,La)CO_(3)F晶粒经500℃焙烧后,脱硝效果最佳,当催化反应温度为200℃时,NO_(x)转化率为34%。负载Mn-Fe及硫酸酸化联合作用可激发(Ce,La)CO_(3)F催化剂组分的活性,联合作用下的催化剂经400℃焙烧后,获得了93%的NO_(x)转化率(催化反应温度250℃)。通过原位红外技术探究了(Ce,La)CO_(3)F催化剂的反应机理。结果表明:负载Mn-Fe及硫酸酸化(Ce,La)CO_(3)F催化剂表面反应主要遵循E-R机理,反应物种为NH_(3)(g)吸附在催化剂表面产生的NH^(+)_(4)/NH_(3)(a)和NO,经一系列中间反应生成N_(2)和H_(2)O。本研究可为稀土精矿作为脱硝催化剂利用提供理论指导。

Bayan Obo bastnaesite was selected as the research object,and according to its Ce/La mass ratio,(Ce,La)CO_(3)F crystal grains were synthesized by hydrothermal method to study their NH_(3)-SCR denitration performance.The results show that(Ce,La)CO_(3)F synthesized by adding excess NaHCO_(3)has better catalytic effect.After roasted at 500℃,the(Ce,La)CO_(3)F grains have the best denitration effect,and the NO_(x) conversion rate is 34%at the catalytic reaction temperature of 200℃.The combined action of Mn-Fe loading and sulfuric acid acidification can excite the active components of(Ce,La)CO_(3)F catalyst.After the catalyst with the combined action is roasted at 400℃,the NO_(x) conversion rate of 93%is obtained at the catalytic reaction temperature of 250℃.The reaction mechanism of(Ce,La)CO_(3)F catalyst was explored by in-situ infrared technology.The results show that the surface reaction of Mn-Fe loaded and sulfuric acid acidified(Ce,La)CO_(3)F catalyst mainly follows the E-R mechanism.The reactive species are NH^(+)_(4)/NH_(3)(a)generated by NH_(3)(g)adsorption on the catalyst surface and NO,which undergo a series of intermediate reactions to produce N_(2) and H_(2)O.This study can provide theoretical guidance for the use of rare earth concentrates as denitration catalysts.