F改性NiW/Al2O3-SiO2催化剂煤焦油加氢性能研究

Hydroprocessing of coal tar on fluorine modification NiW/Al_2O_3-SiO_2 catalysts

采用等体积浸渍法,以实验室自制的Al_2O_3-SiO_2载体制备出不同F含量的煤焦油馏分油加氢NiWF/Al_2O_3-SiO_2系列催化剂,在固定床反应装置上以低于360℃煤焦油馏分油为原料对各催化剂试样进行加氢反应评价。采用N_2吸附-脱附、NH3-TPD、XRD、SEM、GC-MS等方法对催化剂及加氢产物进行了表征。表征结果显示,F的加入对NiWF/Al_2O_3-SiO_2催化剂的比表面积和孔结构影响不明显,活性金属分散均匀,随着F含量的增加,催化剂的强酸酸量先增加后下降,弱酸酸量反之。实验结果表明,不同F含量催化剂对石脑油和柴油收率的影响较为显著;当F含量为1.0%(w)时,加氢产物中的S和N含量显著下降,脱N率最高,同时石脑油和柴油收率最大;随着F含量的增加,芳烃的饱和程度及产物的基团分布发生了变化,其中NiWF-1.0催化剂的芳烃饱和活性最高,产物中环烷烃的含量达到了47.3%(w)。

A series of NiW/Al2O3-SiO2 catalysts with different F contents were prepared by equal volume impregnation with self-made carrier Al2O3-SiO2 and the hydroprocessing of the fraction of coal tar below 360℃was carried out in a fi xed-bed reactor.Catalysts and products were characterized by N2 adsorption-desorption,NH3-TPD,XRD,SEM and GC-MS.The results showed that the addition of F had little effect on the specifi c surface area and pore structure of NiWF/Al2O3-SiO2 catalyst.In addition,active metals were evenly dispersed on the surface of the carrier.With the increasing content of F,the content of strong acid increased fi rst and then decreased,and weak acid in contrast.The experimental results showed that the effect of the F content on the yield of naphtha and diesel oil was obvious.The S and N contents of the product decreased obviously,and the rate of denitrifi cation and the yield of naphtha and diesel were highest when the content of F was 1.0%(w).In addition,with the increasing content of F,the saturation degree of aromatics and the distribution of the product were changed.The NiWF-1.0 catalyst had the highest aromatic activity and the content of cycloalkane in the product reached 47.3%(w).