摘要
利用急冷方法制备了骨架Fe50Al50合金催化剂,详细研究了其物化性质以及引入金属Mn和K对催化剂物化性质和费托合成催化性能的影响。与传统Raney Fe催化剂相比,急冷Fe催化剂具有较大的比表面积、孔体积,较小的平均孔径,双孔分布中的大孔孔径相对较小,铁的晶粒较小,具有更多桥式CO活性吸附中心。与相近组成的沉淀铁催化剂对比结果表明:急冷FeMnK催化剂具有较小的比表面积和平均孔径,更大的颗粒密度,更高的F-T合成反应活性。在543 K、1.5 MPa、2.0 NL/(g-Fe.h)、H2/CO比为1的反应条件下,在1000 h运转期内,CO转化率达到了90%以上,甲烷选择性为7%左右,C5+选择性为70%左右。
A novel, rapidly quenched skeletal Fe catalyst was prepared by alkali leaching of the Fe50Al50 alloy solidified by the rapid quenching technique and tested in gas phase Fischer -Tropsch synthesis （Frs） . Characteriza tions demonstrated that the RQ Fe catalyst had larger specific surface area, smaller crystallite size, higher population of the Fe （111 ） surface, and more strong hydrogen and bridge -carbon monoxide adsorption sites than the conventional Raney Fe catalyst prepared from the naturally solidified Fe50Al50 alloy. The higher F - T activity and selectivity of light hydrocarbons of the RQ Fe catalyst might be ascribed to its smaller mean pore diameter and weaker affinity between carbon and iron on the bridge - carbon monoxide adsorption sites. The RQ FeMnK catalyst was prepared with addition of manganese and potassium promoters by means of alloying and impregnating, respectively. It was compared with precipitated iron catalyst with similar contents. The resuhs showed that RQ FeMnK catalyst exhibited higher Fischer- Tropsch synthesis activity, lower surface area and mean pore diameter, and heavier particle density. During the 1000 h time on stream at the reaction condition of 543 K, 1.5MPa, 2.0 NL/g- Fe, H2/CO = 1, CO conversion was above 90% , the selectivity to methane and C5 ＋ in the total hydrocarbon products maintained at about 7% and above 70% , respectively.
出处
《广州化工》
CAS
2013年第7期107-109,139,共4页
GuangZhou Chemical Industry
关键词
费托合成
骨架铁
急冷法
助剂
Fischer - Tropsch synthesis
skeletal iron catalyst
rapid quenching
promoters
