改性SAPO-34分子筛催化剂的SCR脱硝性能

NH_3-SCR performance of modified SAPO-34 molecular sieve

采用浸渍法负载Cu,Mn及Cu-Mn双金属,制备以菱沸石分子筛SAPO-34为载体的低温、廉价、高效的负载型选择性催化还原(SCR)脱硝催化剂.考察了不同活性组分、负载量及煅烧温度对氨选择性催化还原(NH_3-SCR)催化剂活性的影响,并通过BET,XRD,NH_3-TPD,TEM,XPS等多种表征手段对催化剂进行分析.活性测试结果表明,Cu-Mn双金属共同负载的催化剂活性明显优于Cu或Mn单金属负载的催化剂活性,当Cu,Mn的负载量分别为2%和6%,煅烧温度为450℃时,催化剂的活性最佳,在温度为180~330℃之间脱硝效率均能达到90%以上.分析结果表明,Cu-Mn双金属共同负载与单独负载Cu或Mn相比,能够减弱活性组分与分子筛载体的作用,在催化剂表面促进活性组分分散得更加均匀,同时Cu的引入增加了高价态Mn^(4+)和Mn^(3+)的比例,有利于提高催化剂的活性,引入Mn可适当调节Cu^(2+)与Cu^+的比例,有利于拓宽催化剂的活性温度窗口.

The new impregnated catalyst with low temperature,low cost and high efficiency was prepared for NH3-SCR denitration by choosing SAPO-34molecular sieve as support and impregnating Cu,Mn and Cu-Mn.Three factors were studied,such as different active ingredients,impregnated quantity,calcination temperature,and characterized means using nitrogen adsorption-desorption(BET),X-ray diffraction(XRD),NH3temperature programmed desorption(NH3-T PD),transmission electron microscope(TEM)and X-ray photoelectron spectroscopy(XPS).The activity test results show that Cu-Mn bimetallic co-load is better than that of Cu or Mn single metal supported catalyst.When the loading amounts of Cu and Mn are2%and6%respectively,the calcination temperature is450°C,the activity of the catalyst is the best,and it can reach90%or more between180to330°C.The analysis results show that compared with loading Cu or M n,the Cu-Mn can weaken the effects on the active component and the molecular sieve,promote active component dispersed more evenly on the surface of the catalyst.The introduction of Cu can increase the ratio of valent Mn and improve the activity of the catalyst,the introduction of Mn can properly adjust the rate of Cu2+/C u+and broaden the activity temperature window of the catalyst.