白云石质凹凸棒土负载Cr的低温脱硝实验研究

Research on the activity of denitration for CrO_x-DPC catalysts of at low temperature

以白云石质凹凸棒土(DPC)为载体,采用浸渍法负载Cr制备Cr Ox-DPC催化剂,并考察其低温脱硝活性。探究所制备催化剂Cr负载量和焙烧温度对脱硝活性的影响,利用BET、XRD等表征手段对催化剂分析,并考察脱硝工艺条件(空速和氨氮比)对脱硝效率的影响。结果表明:在Cr Ox负载量10%,焙烧温度为500℃时,催化剂的脱硝效率表现最佳,且在反应温度300℃时脱硝效率达到91%以上;在最佳条件下,Cr主要以Cr2O3和无定形态Cr Ox形式存在,催化剂中白云石结构受到破坏而凹凸棒石结构仍较好的存在;催化剂脱硝最佳工艺条件空速为10 000 h-1、氨氮比为1.0。

CrO_x-DPC catalyst is prepared by impregnation method using dolomite attapulgite（DPC） as carrier and CrO_x as active component. The effects of Cr loading and roasting temperature on the denitrification activity are investigated, which is analyzed by BET, XRD and other characterization methods. In addition, the effects of denitration process conditions（gas hourly space velocity and NH3/NO ratio） on the denitration efficiency are put out. The results show that the catalyst, loaded with 10% CrO_x and calcinated at 500 ℃, show the best denitration efficiency, with the denitration efficiency reaches above 91% at the reaction temperature of 300 ℃. Under the optimal conditions, the existed active component forms are Cr2 O3 and amorphous CrO_x, otherwise, the dolomite structure in the catalyst was destroyed and the attapulgite structure still existed. Finally, the optimum condition is at the situation with space velocity at 10 000 h-1 and the ratio of NH3 to NO at 1.0.