V\Ni\Mo sulfide supported on Al 2 O 3 : Preparation, characterization and LCO hydrotreating Paulino Betancourt a, ⁎, Santiago Marrero a , Susana Pinto-Castilla a, b, 1 a Universidad Central de Venezuela, Facultad de Ciencias, Escuela de Química, Centro de Catálisis, Petróleo y Petroquímica, Los Chaguaramos, Caracas, AP. 40679, Venezuela b Universidad Central de Venezuela, Facultad de Ingeniería, Dpto. de Química Aplicada, Caracas, Venezuela abstract article info Article history: Received 23 May 2009 Received in revised form 14 October 2012 Accepted 14 March 2013 Available online 13 April 2013 Keywords: Hydrotreating Light cycle oil Nickel–molybdenum sulfides Vanadium sulfide The effect of vanadium incorporation on the HDS, HDN, and HDA activities of LCO hydrotreating was investigated on NiMo supported hydrotreating catalysts. The catalysts were characterized by XRD, BET, XPS, NO-chemisorption and evaluated in fixed bed reactor using real LCO as feed. The vanadium promoted NiMo catalyst presented higher HDS and HDN activities, and surprisingly a relatively low activity toward the HDA. This behavior is probably due to a vanadium-mixed active phase, this has superior conversion as compared to NiMo catalyst. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Light cycle oil (LCO) is a by-product of the fluid catalytic cracking process in a petroleum refinery. LCO has a low cetane index (15–20), high sulfur content (3 wt.%), and 50–80 wt.% of aromatics [1]. Besides its high sulfur content, the HDS of LCO is complicated because its sulfur is distributed in the form of highly refractory dibenzothiophenes [2]. Its use in the diesel pool, therefore, requires extensive hydrotreating to meet existing diesel fuel combustion and environmental specifications. While the increasing stringency of sulfur specifications has motivated intensive HDS research, there have been few studies on real feedstocks, such as LCO. Most studies have developed on mixtures of model com- pounds [3–5]. Reports of HDS of real feedstocks have often used hydrotreated or low sulfur LCO [6–11] or feedstock blends with LCO as one of the components [12–15]. Considerable attention has been de- voted to the development of catalysts and processes for LCO upgrade, with particular reference to aromatic saturation. This has opened up a challenge for the preparation of new catalysts capable of processing these feeds. One approach for designing the more efficient catalysts consists in the addition of small amounts of vanadium to conventional NiMo catalysts. In this respect, only some studies reported on the use of vanadium catalysts in hydrotreatment reactions. In the study carried out by Rankel and Rollman [15], showed that the resultant vanadium sulfide deposit was active, although less active than CoMo supported catalyst, for hydrotreatment. In this sense, Asaoka et al. [16] claimed that V 3 S 4 deposited during HDM reaction has an autocatalytic activity for HDM and hydro-deasphaltening. On the other hand, the activity in toluene hydrogenation (HYD) on NiMo catalyst increase with the progressive V deposits [17], proposes that the structure of VMoS phase has a synergetic effect. Yumoto et al. [18] compared the activity of a NiMoS/Al 2 O 3 catalyst used for along one year in a continuous commercial process. The spent catalyst (2.7 wt.% of V) lost nearly all of its initial activity whatever the hydrotreating reaction (HYD, HDS or HDN) but becomes similar to the fresh catalyst after burn- ing off the coke deposits. Lacroix et al. [19] prepared vanadium sulfides from a thio-salt (ammonium tetra thiovanadate) obtained an activity that was equal or slightly higher than that of Mo and W sulfides in HDS of DBT and hydrogenation of biphenyl, respectively. Being this consistent with the results obtained with vanadium sulfide which has an intrinsic toluene hydrogenation activity 1.5 times higher than MoS 2 at high pressure [20]. In our group, we have obtained in the unsupported Ni\V system, which is about 10 times more active than the pure VS x in the thiophene HDS, and seven times more active than MoS 2 [21,22]. In this work, NiMo/Al 2 O 3 catalysts have been modified with vanadium in order to enhance their hydrotreatment function. The ternary catalysts were prepared by wet impregnation of the NiMo samples with vanadium salt solution. Catalyst screening has been performed in the reaction of hydrotreatment (HDT) of LCO. The effect of promoter (V) and V-loading have been investigated. The physicochemical properties of the oxide pre- cursors and spent catalysts have been evaluated by various techniques (SSA, 51 V NMR, XPS, TPO) in order to elucidate factors influencing the catalyst response. Fuel Processing Technology 114 (2013) 21–25 ⁎ Corresponding author. Tel.: +58 212 6051649; fax: +58 212 6051220. E-mail address: paulino.betancourt@ucv.ve (P. Betancourt). 1 Tel.: +58 212 6053034. 0378-3820/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fuproc.2013.03.013 Contents lists available at SciVerse ScienceDirect Fuel Processing Technology journal homepage: www.elsevier.com/locate/fuproc