Traps for simultaneous removal of SO x and vanadium in FCC process Luis Ceden ˜o Caero a,b, * , Luis C. Ordo ´n ˜ez a , Jorge Ramı ´rez a , Francisco Pedraza b a UNICAT, Facultad de Quı ´mica, Universidad Nacional Auto ´noma de Me ´xico, Cd. Universitaria, 04510 Mexico D.F., Me ´xico b Instituto Mexicano del Petro ´leo, 07730 Me ´xico D.F., Me ´xico Available online 16 August 2005 Abstract Simultaneous removal of SO x and vanadium under simulated fluid catalytic cracking (FCC) regenerator conditions was studied over mixed oxide traps of Ti–Al–Mg doped with La. These materials were prepared by the sol–gel method and characterized by DTA/DTG, X-ray diffraction (XRD), N 2 adsorption–desorption, SEM–EDX and UV–vis–DRS. The capacity of the traps was determined by means of a thermogravimetric study for SO x removal and V capture hydrothermal tests followed by chemical analysis for vanadium trapping. The traps performance results under simulated FCC conditions show that these traps exhibit an excellent performance for SO x removal with the presence of vanadium compounds, and high V capacity in presence of sulphated compounds. # 2005 Elsevier B.V. All rights reserved. Keywords: FCC; Mixed oxides; Lanthanum; SO x removal; Ti–Al–Mg; Vanadium traps 1. Introduction The catalytic performance of the ultra stable Y zeolite used as catalyst in the fluid catalytic cracking (FCC) process is seriously affected by metal contaminants, such as vanadium or nickel, presents in crude oil as organic complexes. These organic species, mostly porphyrins, are deposited on the catalytic surface and V oxide compounds are formed. Vanadium compounds promote undesirable dehydrogenation reactions, which increase coke production at the expense of gasoline yield [1]. Moreover, vanadium decreases the overall catalytic activity and selectivity by destroying the zeolite crystallinity. In the FCC reactor, the porphyrins containing vanadium in +3 or +4 oxidation states are decomposed and the reduced vanadium deposits onto the surface of the catalyst, along with coke. In the regenerator, coke burns off the catalyst and the vanadium oxidizes into the +4 and +5 state. Then, mobile vanadium species, such as vanadic acid, are formed by reaction of the oxidized vanadium with steam. Vanadic acid can move from particle to particle and can also migrate into the catalyst, accelerating the deactivation of fresh catalyst particles. A method of protecting the catalysts from V deactivation is to use traps that prevent V from contacting with the catalyst [2]. One common type of V traps contains a basic species that reacts with and neutralizes acidic V compounds. Among the compounds that have been proposed as V traps are titania and magnesium oxides. These basic compounds theoretically react with vanadic acid and bind it in the trap. Another important problem in the FCC process is the presence of pollutants, such as SO x . During the coke burn- off in the FCC regenerator, sulfur oxides are converted into sulfate on the catalyst, which is subsequently released as H 2 S in the reactor. This step rejuvenates the catalyst, which is then recirculated through the regenerator, and the cycle is repeated. Group IIA metals favor the capture of SO 3 and the formation of metal sulfate. In addition, Al 2 O 3 has been disclosed as a potential oxide for the capture of SO 3 . The materials most used in SO x reduction are additives that contain MgO or rare-earth oxides supported on alumina [3,4]. Depending on the concentration and nature of the trap components, vanadium trap materials may or may not be affected by sulfur competition. In industrial applications, different traps are used specifically for SO x or V removal. To tackle the problem of simultaneously removing SO x and vanadium, we proposed in previous studies [5,6], the www.elsevier.com/locate/cattod Catalysis Today 107–108 (2005) 657–662 * Corresponding author. Tel.: +52 55 56225366; fax: +52 55 56225366. E-mail address: caero@servidor.unam.mx (L.C. Caero). 0920-5861/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.cattod.2005.07.047