摘要
采用真空浸渍法制备负载型铁基催化剂,并利用X射线衍射(XRD)、H2程序升温还原(H2-TPR)、NH3程序升温脱附(NH3-TPD)和N2物理吸附(BET)实验对催化剂进行表征,并考察了不同载体和助剂对负载型Fe基催化剂上合成气制低碳烯烃反应的影响以及不同反应条件对FeMnK/Al2O3催化剂反应性能的影响。结果表明:Al2O3负载的Fe基催化剂可提高活性组分Fe的分散度和金属载体相互作用,且催化剂焙烧后孔径显著增大,有利于产物低碳烯烃的快速移出,因而比SiO2负载催化剂具有更高的催化活性和低碳烯烃选择性;在Fe/Al2O3中加入Mn和K助剂使活性组分Fe更容易还原,提高了活性组分和助剂的分散度,并降低催化剂的表面酸性,从而提高了CO的转化率和低碳烯烃选择性;FeMnK/Al2O3催化合成气制低碳烯烃反应在空速1 000 h-1,温度350℃,压力1.5 MPa,氢碳物质的量之比1.5的条件下,CO转化率达到97.4%,低碳烯烃选择性为55.9%。
The supported Fe based catalysts were prepared by vacuum impregnation method,and were characterized by means of X-ray diffraction（XRD）,temperature-programmed reduction of hydrogen（H2-TPR）,temperature-programmed desorption of ammonia（NH3-TPD） and N2-physisorption techniques（BET）.Effects of different supports and promoters on performance of supported Fe based catalyst for synthesis of light alkenes from syngas and the performance of FeMnK/Al2O3 catalyst under different reaction conditions were investigated.The results showed that the Fe based catalyst supported on alumina exhibited better catalytic activity and selectivity for light alkenes than those of catalyst supported on SiO2,because the active component Fe on alumina had higher dispersity and stronger metal support interactions（SMSI）,and the increased average pore size of catalyst support on alumina after calcination was suitable to the light alkenes to remove fastly from the catalyst surface.With addition of Mn and K as the promoter of catalyst Fe/Al2O3,the Fe reduction property was enhanced,the dispersity of active component and promoters was improved,and the catalyst basicity was increased largely,therefore,the catalytic activity of the catalyst and the selectivity of light alkenes were increased greatly.Under the conditions of space velocity 1 000 h-1,reaction temperature 350 ℃,reaction pressure 1.5 MPa,and the molar ratio of hydrogen to carbon monoxide 1.5,the conversion of CO and the selectivity of C2=-C4= over catalyst FeMnK/Al2O3 reached 97.4% and 55.9%,respectively.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2010年第6期486-493,共8页
Chemical Reaction Engineering and Technology
