Ni含量对负载型NiO/ZnO-TiO2吸附剂结构及吸附脱硫性能的影响

Impact of Ni content on the structure and adsorption desulfurization performance of Ni/ZnO-TiO2 adsorbent

  • 摘要: 以ZnO-TiO2为载体,采用等体积浸渍法制备了不同Ni含量的NiO/ZnO-TiO2汽油脱硫吸附剂。采用X射线衍射(XRD)、压汞、H2程序升温还原(H2-TPR)和H2程序升温脱附(H2-TPD)等手段对吸附剂进行了表征。同时,采用FCC轻汽油为原料,在固定床反应装置中对不同Ni含量的NiO/ZnO-TiO2吸附剂进行脱硫性能评价,以考察Ni含量对该吸附剂脱硫性能的影响。结果表明,Ni含量适量增加对于吸附剂比表面积、内部孔道分布和颗粒强度影响较小,同时能够增加具有脱硫活性的Ni0物种,促进吸附剂脱硫活性。当吸附剂中Ni质量分数达到5.48%后,吸附剂的内部孔道分布改变,吸附剂的比表面积和颗粒强度明显降低,对吸附剂脱硫活性极为不利。当Ni质量分数为4.45%时,吸附剂具有最佳脱硫性能,能够将FCC轻汽油中3×10-4的总硫含量降低至5×10-6以下,并维持脱硫时间达152 h,穿透硫容达11.24%(112.4 mg S/g吸附剂),且脱硫后FCC轻汽油烯烃含量变化较小。

     

    Abstract: Using ZnO-TiO2 as a carrier support, Ni/ZnO-TiO2 gasoline desulfurization adsorbents with different Ni contents were prepared by equal volume impregnation method and characterized by X-ray diffraction (XRD), Mercury intrusion porosimetry, H2-temperature-programmed desorption(H2-TPD) and H2-temperature-programmed reduction (H2-TPR). Meanwhile, the desulfurization performance of the Ni/ZnO-TiO2 adsorbents were evaluated using FCC light gasoline in a fixed bed reactor. The results show that proper increase of Ni content has little effect on the specific surface area, internal pore distribution and particle strength of the adsorbent, and can increase the Ni0 species with desulfurization activity and promote the desulfurization activity of the adsorbent. When the content of Ni in the adsorbent is too much, the internal pore distribution of the adsorbent changes, and the specific surface area and particle strength of the adsorbent are greatly reduced, which is extremely detrimental to the desulfurization activity of the adsorbent. When the Ni content is 4.45%, having the best desulfurization performance, can reduce the total sulfur content of 3×10-4 in FCC light gasoline to below 5×10-6, and maintain the desulfurization time up to 152 h, and the breakthrough sulfur capacity is 11.24% (112.4 mg S/g adsorbent). And the olefin content of FCC light gasoline after desulfurization changes little.

     

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