湿混捏法制备NiO/Al_(2)O_(3)重整生成油选择性加氢催化剂

Preparation of NiO/Al_(2)O_(3) reformate oil selective hydrodeolefine catalyst prepared with wet-mixing kneading method

以氢氧化铝干胶和六水合硝酸镍为原料,采用湿混捏法制备不同NiO含量的NiO/Al_(2)O_(3)催化剂,利用N_(2)吸附-脱附、XRD、NH_(3)-TPD、TPR和Py-IR等方法对所制备催化剂进行表征,以溴指数为4300 mg(100 g Br)的重整生成油为评价原料对所制备催化剂进行选择加氢脱烯烃活性评价。实验结果表明,在NiO含量30%~50%(w)的范围内,随着NiO含量的增加,NiO/Al_(2)O_(3)催化剂的比表面积和孔体积逐渐减小,平均孔径增大,总酸量增加,NiO的粒径逐渐增大;NiO/Al_(2)O_(3)催化剂只有L酸,没有B酸,NiO含量为30%(w)时,NiO晶粒较小,分散相对均匀,芳烃加氢率最高,烯烃选择加氢活性较低;NiO含量大于40%(w)时,NiO晶粒逐渐变大,出现镍铝尖晶石晶相,芳烃加氢活性降低,烯烃加氢选择性增加。

Using aluminum hydroxide dry glue and nickel nitrate hexahydrate as raw materials,NiO/Al_(2)O_(3)catalysts with different NiO contents were prepared by wet-mixing kneading method.The prepared catalysts were characterized by BET,XRD,NH_(3)-TPD,TPR and Py-IR.The prepared catalysts were evaluated by selective hydrodeolefination with the bromine index of 4300 mg(100 g Br)reformate oil as the evaluation raw materials.The results show that in the range of NiO content from 30%-50%(w),with the increase of NiO content,the specific surface area and pore volume of NiO/Al_(2)O_(3)catalyst gradually decrease,the average pore size increases,the particle size of NiO gradually increases,and the amount of acid increases.The NiO/Al_(2)O_(3)catalyst has only L acid but no B acid.When the NiO content is 30%(w),the NiO grains are small,the dispersion is relatively uniform,the aromatics hydrogenation activity is the highest,and the olefin selective hydrogenation activity is low.As the NiO content is greater than 40%(w),nickel-aluminum spinel crystal phases appear,NiO crystal grains become larger,aromatics hydrogenation activity decreases,and olefin selective hydrogenation activity increases.