Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (7): 1309-1317.doi: 10.3866/PKU.WHXB201405043

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of TiO2-Al2O3 Support Preparation Technique on Hydrodenitrogenation of Ni2P/TiO2-Al2O3 Catalysts

YAN Jing-Sen1,2,3, WANG Hai-Yan1,2, ZHANG Jing-Ru2, XU Hui-Juan3   

  1. 1. Department of Chemical Engineering, China University of Petroleum East China, Qingdao 266555, Shandong Province, P. R. China;
    2. Institute of Petrochemical Technology, Liaoning Shihua University, Fushun 113001, Liaoning Province, P. R. China;
    3. Institute of Biomedical and Chemical Engineering, Liaoning Institute of Science and Technology, Benxi 117004, Liaoning Province, P. R. China
  • Received:2014-02-11 Revised:2014-04-30 Published:2014-06-30
  • Contact: WANG Hai-Yan E-mail:fswhy@126.com

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Abstract:

TiO2-Al2O3 composite supports were prepared by in situ sol-gel and co-precipitation methods, and the supported nickel phosphide catalysts were prepared by incipient wetness impregnation and the in situ H2 reduction method. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption (BET), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and inductive couple plasma atomic emission spectrometry techniques (ICP-AES). The hydrodenitrogenation (HDN) activity of the supported nickel phosphide catalysts were evaluated on a continuousflow fixed-bed reactor using quinoline as the model molecule. The results showed that the composite support prepared by the in situ sol-gel method basically retained the original pore properties of γ-Al2O3 but with a larger surface area and decentralized pore size distribution, and TiO2 was enriched on the tubular γ-Al2O3 surface. The composite support prepared by the co-precipitation method had a smaller surface area and a centralized pore size distribution, and TiO2 was evenly dispersed on the massive γ-Al2O3 surface. The main active phases after reduction were Ni2P and Ni12P5 for the catalyst supported on sol-gel prepared TiO2-Al2O3, but only Ni2P for the catalyst supported on co-precipitated TiO2-Al2O3. Different TiO2-Al2O3 preparation techniques and different Ti/Al atomic ratios had a great effect on the HDN activity of the catalysts. The catalyst supported on co-precipitated TiO2-Al2O3 exhibited better reducibility and HDN activity than the catalyst supported on in situ sol-gel prepared TiO2-Al2O3. The optimal HDN activity occurred for the catalyst supported on co-precipitated TiO2-Al2O3 with an initial Ti/Al atomic ratio of 1:8. At a reaction temperature of 340 ℃, pressure of 3 MPa, hydrogen/oil volume ratio of 500, and liquid hourly space velocity of 3 h-1, the HDN conversion of quinoline was 91.3%.

Key words: Nickel phosphide, Titania, Alumina, Composite support, Co-precipitation method, Sol-gel method, Hydrodenitrogenation