磷钼酸改性Ni催化剂上秸秆液化油的加氢脱氧研究

摘要

秸秆是重要的农弃物资源,催化秸秆液化油加氢脱氧提高燃油品质,这对于优化利用农弃物资源和开发新能源都具有十分重要的意义.以γ-Al2O3为载体,通过浸渍法制备了负载型Ni催化剂(Ni/γ-Al2O3)和磷钼酸改性的Ni催化剂(Ni/γ-Al2O3-HMoP),采用氮气吸附(BET)、X射线衍射(XRD)、程序升温还原(H2-TPR)和程序升温脱附(NH3-TPD)对催化剂的物性进行了表征,并考察了磷钼酸对催化剂在秸秆液化油催化加氢精制中的性能的影响.结果显示,磷钼酸改性可有效提高催化剂对秸秆液化油的催化加氢脱氧活性.磷钼酸改性一方面可增加活性金属在催化剂载体上的分散,并使Ni活性粒子在载体微孔内尺寸大小趋于均匀,有利于活性组分Ni的分散,使催化剂具有更好的选择性和催化稳定性;另一方面,引入的磷钼酸与镍盐发生相互作用,提高了镍的还原性和活性位数量.秸秆液化油的加氢脱氧反应结果显示,在10%Ni/γ-Al2O3-HMoP-3催化剂上,温度250℃,氢气压力4.5MPa,秸秆液化油的催化加氢脱氧反应较为彻底,精制油颜色明显变浅.%Ni/γ-Al2O3 and phosphomolybdic acid promoted Ni/γ-Al2O3-HMoP catalysts were prepared by impregnation, and characterized by BET, XRD, H2-TPR and NH3-TPD. The effect of phosphomolybdic acid on catalytic performance of the catalysts in hydrogenation of straw liquefied oil was investigated. The results showed that phosphomolybdic acid modification can effectively improve the catalytic activity in the hydrodeoxygenation of straw liquefied oil. Phosphomolybdic acid modification, on the one hand, can increase the dispersion of the active metal on the surface of catalyst support, and make the sizes of the active Ni particles in the micropores of support tend to be uniform, which promotes the dispersion of active Ni species, and increases selectivity and stability of the catalyst. On the other hand, the interaction between phosphomolybdic acid and nickel salt improves the activity and reducibility of nickel. Over the catalyst 10%Ni/γ-Al2O3-HMoP-3, the most complete hydrogenation of straw liquefied oil can be obtained at the conditions of 250℃and 4.5MPa, and the color of the refined oil becomes shallow obviously.