不同助剂改性γ-Al_2O_3对WNi/γ-Al_2O_3催化剂性能的影响

Effect of γ-Al_2O_3 modified by different additives on performances of WNi/γ-Al_2O_3 catalyst

采用表面浸渍法用B,P,Ti,Zr4种助剂对Al2O3表面进行化学改性。采用浸渍法将活性金属负载到改性Al2O3载体上,获得WNi/γ-Al2O3催化剂。运用X射线衍射、红外光谱、程序升温还原等手段表征了改性γ-Al2O3和WNi/γ-Al2O3催化剂的性能。以正十二烷为原料,考察了4种助改性剂对WNi/γ-Al2O3催化剂加氢裂化活性和选择性的影响。结果表明,4种助剂的改性效果不同,P改性Al2O3的比表面积比其他3种改性剂改性的比表面积大,改性前后晶体的结构没有发生显著变化;P改性WNi/γ-Al2O3催化剂的总酸量显著降低;Ti能够大幅度降低WNi/γ-Al2O3催化剂的还原温度;Zr改性WNi/γ-Al2O3催化剂的转化率显著降低。

Abstract：The surface of γ-Al2O3was chemically modi- fied by four different additives B,P,Ti,Zr by surface immersion method. With the modified γ-Al2O3 as carriers, W and Ni as reactive metals,WNi/γ-Al2O3 catalysts were prepared by impregnation method. The properties of modified γ-Al2O3 and WNi/γ-Al2O3 catalyst were characterized by X- ray diffraction （ XRD ） , infrared spectroscopy （ IR ） , temperature programmed reduction （ H2 - TPR） and so on. The effect of four additives on the hydrocracking activity and selectivity of WNi/γ-Al2O3 was investigated with n - dodeeane as raw material. The results showed that four additives had differentmodification effects, the specific surface area ofγ-Al2O3 modified by P was larger than modified by other three addi- tives, the structure of the crystal had no obvious change before and after modification,and the total acid content of WNi/γ-Al2O3catalyst modified by P decreased remarkably, Ti reduced the reduction temperature of WNi/γ-Al2O3 catalyst dramatically;and the conversion of WNi/γ-Al2O3catalyst modified by Zr reduced obviously.