BEA and MOR as additives for light olefins production Alexandre F. Costa a , Henrique S. Cerqueira b, * , Jose ´ Marcos M. Ferreira a,1 , Naira M.S. Ruiz c , Sonia M.C. Menezes b a Petrobras, Centro de Pesquisas e Desenvolvimento Leopoldo A. Miguez de Mello (CENPES), P&D do Abastecimento, Tecnologia em FCC, Av. Jequitiba ´ 950, Ilha do Funda ˜o, 21941-598 Rio de Janeiro, RJ, Brazil b Petrobras, Centro de Pesquisas e Desenvolvimento Leopoldo A. Miguez de Mello (CENPES), P&D em Ga ´s, Energia e Desenvolvimento Sustenta ´vel, Av. Jequitiba ´ 950, Ilha do Funda ˜o, 21941-598 Rio de Janeiro, RJ, Brazil c PUC-Rio, R. Marques de Sa ˜o Vicente 225, Ga ´vea, 22453-900 Rio de Janeiro, RJ, Brazil Received 9 September 2006; received in revised form 21 November 2006; accepted 22 November 2006 Available online 15 December 2006 Abstract The use of MFI-based additives in the fluid catalytic cracking (FCC) process in order to increase both – the production of light olefins and gasoline octane number – has been commercially proven. It is well known that impregnation by phosphorus increases the stability of aluminum atoms of H-MFI zeolite framework, resulting in higher yields of desired products. This paper discusses the possibility of combining either beta (BEA) or mordenite (MOR) zeolites – before and after treatment – with phosphoric acid (P/Al ratio of 1) with the conventional MFI-based additive. Zeolite samples were characterized by nitrogen adsorption, X-ray diffraction (XRD) and 27 Al and 31 P solid state NMR before and after hydrothermal treatment. Such treatment was responsible for decreases in zeolite surface area, crystallinity and also in the number of framework tetrahedral aluminum species of all samples. After impregnation with phosphoric acid and hydrothermal treatment, besides other species, both H- MOR/P/St and H-BEA/P/St presented resonance signals at 38 and 30 ppm at the 27 Al and 31 P MAS NMR spectra, respectively, which can be attributed to tetrahedral aluminum and phosphorus in AlPO’s-like crystalline structures. After being mixed with an equilibrium FCC catalyst, the laboratory performance of the different additives was investigated using a gasoil feedstock and a fixed-bed micro activity test unit. Similarly to what was previously reported for H-MFI/P/St, the phosphoric acid treatment improved the performance of H-MOR/P/St and H-BEA/P/St zeolites with an expressive increase in lighter products yields in detriment of naphtha. The results suggest that, besides classical tetrahedral aluminum in the framework (Al tet-f ), other aluminum species also take part in the improvement of the zeolites performance. # 2006 Elsevier B.V. All rights reserved. Keywords: MFI; BEA; MOR; NMR; Phosphorus; Additive 1. Introduction Among the various downstream operations applied to adapt product yields to market demand, fluid catalytic cracking (FCC) is still one of the most important. In the FCC process, heavy feedstocks (gas oils from a vacuum distillation tower or residues from an atmospheric distillation tower) are converted into lighter more valuable products such as liquefied petroleum gases (LPG) and gasoline. Together with the desired cracking reactions, coke formation (hydrocarbons retained in the pore structure of the catalyst after stripping) also occurs. That is why the FCC process has three main steps: reaction, separation and regeneration. Besides the main catalyst, several additives may be applied in the FCC process. One of the mostly used has MFI zeolite as the active component and it is meant to maximize the yield of light olefins (especially propene) and also to improve gasoline octane [1]. Previous works have studied the impact of MFI additives in the FCC catalyst performance [2–5] as well as the interaction between phosphorus and MFI [6–11]. Furthermore, previous papers have discussed the potential application of other zeolites alone, such as mordenite (MOR) [12], beta (BEA) [13] and MCM-22 [14] in cracking reactions. Nevertheless, the application of a dual zeolite system was proposed only more recently for gasoline upgrading [15–17]. In the present paper, zeolite samples were characterized by nitrogen adsorption, X-ray diffraction (XRD) and 27 Al and www.elsevier.com/locate/apcata Applied Catalysis A: General 319 (2007) 137–143 * Corresponding author. Tel.: +55 21 3865 6635; fax: +55 21 3865 6626. E-mail address: henriquecerqueira@petrobras.com.br (H.S. Cerqueira). 1 Present address: Braskem, Insumos Ba ´sicos, Tecnologia de Processos-Rua Eteno 1561, Po ´lo Petroquı ´mico de Camac ¸ari, Camac ¸ari, Bahia, Brazil. 0926-860X/$ – see front matter # 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.apcata.2006.11.027