Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (03): 661-666.doi: 10.3866/PKU.WHXB201112291

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of Citric Acid on the Hydrodesulfurization Performance of Ni2P/TiO2-Al2O3 Catalyst

SONG Hua1,2, ZHANG Yong-Jiang1, SONG Hua-Lin3, DAI Min1   

  1. 1. College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang Province, P. R. China;
    2. Provincial Key Laboratory of Oil & Gas Chemical Technology, Northeast Petroleum University, Daqing 163318, Heilongjiang Province, P. R. China;
    3. Department of Image School, Mudanjiang Medical University, Mudanjiang 157011, Heilongjiang Province, P. R. China
  • Received:2011-08-05 Revised:2011-12-07 Published:2012-02-23
  • Contact: SONG Hua
  • Supported by:

    The project was supported by the Heilongjiang Science and Technology Agency, China (2009G0947-00).

Abstract: A TiO2-Al2O3 complex support was prepared by the sol-gel method. Nickel phosphide catalyst, Ni2P/TiO2-Al2O3, with citric acid (CA) as a chelating agent, was prepared by impregnation. The catalyst was characterized by X-ray diffraction (XRD), BET specific surface area measurements, H2-temperature programmed reduction (TPR) and temperature programmed oxidation (TPO), and X-ray photoelectron spectroscopy (XPS). The effects of the molar ratio of CA to Ni on catalyst activity for hydrodesulfurization (HDS) of dibenzothiophene (DBT) were studied. Addition of an appropriate amount of CA into the catalyst can change the pores of the Ni2P/TiO2-Al2O3 catalyst, increasing the surface area. The specific surface area reached 126.75 m2·g-1 for n(CA)/n(Ni) of 2/1, an improvement of 57.05 m2·g-1 compared with the catalyst without CA. Regulating n(CA)/n(Ni) can improve the distribution of the active phase and change the active phase species. Addition of CA decreased the temperature required for reduction of nickel and the phosphorus precursor, as well as promoting the formation of the active phase. CA can limit the deposition of carbon on the catalyst surface to some extent, improving its stability. A molar ratio of n(CA)/n(Ni) of 2/1 was found to be optimal for the catalytic activity of the Ni2P/TiO2-Al2O3 catalyst prepared with CA as a chelating agent. At a reaction temperature of 360 °C, pressure of 3.0 MPa, hydrogen/oil ratio of 500 (V/V), and liquid hourly space velocity of 2.0 h-1, the HDS conversion of DBT was 99.5%, which can reduce the sulfur content of a model oil from 2% (w) to 0.01% (w).

Key words: Hydrodesulfurization, Nickel phosphide, Titanium dioxide, Al2O3, Citric acid, Chelating agent


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