Initiation behaviour in hydrogenation of pyrolysis gasoline over presulphided Ni-Mo-Zn/Al2O3 catalystZi-Xia Li, Wei Sun, Shun-Qin Liang, and Huan-Ling Song aState Key laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road, No. 18, Lanzhou 730000, China
E-mail: wsun@licp.cas.cn Abstract: A presulphided treatment was applied to the oxidic Ni-Mo-Zn/Al2O3 catalyst (nickel catalyst) in order to avoid thermal run-away during initiation of the hydrogenation of pyrolysis gasoline. The physico-chemical properties of the prepared oxidic nickel catalyst, the reduced and passivated (RP) nickel catalyst and the sulphided (RPS) nickel catalyst were characterised using N2 adsorptiondesorption, X-ray diffraction, temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The TPR results showed that the reducibility of the RP Ni-Mo-Zn/Al2O3 catalyst was improved over the oxidic nickel catalyst. The XPS spectra confirmed the binding energy of the RPS nickel catalyst to be higher than that of the oxidic nickel catalyst. The catalytic performance was evaluated on a fixed-bed reactor (reaction temperature between 30 °C and 70°C, at 2.8 MPa of total pressure and weight hourly space velocity of 2.0 h-1, the volume of H2/pyrogasoline = 200 : 1). The rising temperature of the RPS nickel catalyst was almost 20 °C lower than that of the oxidic nickel catalyst during the initial stage of the hydrogenation reaction. The results indicated that the RPS nickel catalyst exhibited better stability than the oxidic nickel catalyst during the start-up period, thereby providing a better selectivity in long- term operation. Keywords: nickel catalyst – presulphided – pyrolysis gasoline – reduction and passivation – selective hydrogenation Full paper is available at www.springerlink.com. DOI: 10.1515/chempap-2016-0013
Chemical Papers 70 (6) 769–776 (2016) |
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