Applied Catalysis B: Environmental 106 (2011) 405–415 Contents lists available at ScienceDirect Applied Catalysis B: Environmental jo ur n al homepage: www.elsevier.com/locate/apcatb Catalytic hydroreforming of the polyethylene thermal cracking oil over Ni supported hierarchical zeolites and mesostructured aluminosilicates J.M. Escola a,∗ , J. Aguado a , D.P. Serrano a,b , A. García a , A. Peral a , L. Briones a , R. Calvo c , E. Fernandez c a Department of Chemical and Environmental Technology, ESCET, Universidad Rey Juan Carlos, c/Tulipán s/n, 28933 Móstoles, Madrid, Spain b IMDEA Energía, c/Tulipán s/n, 28933 Móstoles, Madrid, Spain c URBASER I + D + i, Av. Tenerife 4, 28703 San Sebastian de los Reyes, Madrid, Spain a r t i c l e i n f o Article history: Received 22 March 2011 Received in revised form 23 May 2011 Accepted 28 May 2011 Available online 6 June 2011 Keywords: LDPE Hydroreforming Hierarchical zeolites Al-MCM-41 Al-SBA-15 a b s t r a c t The hydroreforming of the liquid product resulting from LDPE thermal cracking at 400 ◦ C (C 5 –C 40 ) has been studied using Ni supported hierarchical zeolites (Ni/h-ZSM-5, Ni/h-Beta) and mesostructured mate- rials (Ni/Al-MCM-41 and Ni/Al-SBA-15) as catalysts. Hydroreforming experiments were carried out at 310 ◦ C under 20 bar of hydrogen. All the catalysts were synthesized with a Si/Al atomic ratio of 30 and a Ni content of 7 wt%. According to XRD, TPR and TEM data, the activated catalysts displayed Ni par- ticles both over the external surface and inside the catalyst pores in different percentages depending on their porous structure and nature. Complete hydrogenation of the olefins was observed over both mesostructured catalysts (Ni/Al-SBA-15 and Ni/Al-MCM-41) and hierarchical Ni/h-Beta. In contrast, over Ni/h-ZSM-5, there is always left about 30% of olefins, due to an imbalance in the acid and metal function. Ni/h-ZSM-5 led towards significant amounts of gases (∼18%) while gasoline range hydrocarbons were the main products (55%) over Ni/h-Beta, at the expense of diesel fractions. In contrast, the hydrocracking extent was far lower over Ni/Al-MCM-41 and Ni/Al-SBA-15, the latter showing additionally the appear- ance of a slight degree of oligomerization, which led towards an increase in the heavy diesel fraction (C 19 –C 40 ). Hydroisomerization reactions also occur, mostly in the case of Ni supported hierarchical zeo- lites. Likewise, aromatics were formed over these catalysts in a large extent. The RON number of the gasolines obtained at 310 ◦ C was within 81–89 depending on the chosen catalysts while the cetane index (CCI) of the diesel fraction was around 70–80. On the other hand, Ni leaching was not detected. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Plastic wastes are currently a subject of worldwide public con- cern whose importance can be roughly estimated through the following figures. The world production of plastics in 2007 was 260 millions tonnes and the corresponding amount in the European Union (EU) the same year rose to 52.5 million tonnes (∼20%). Poly- olefins (LDPE, LLDPE, HDPE and PP) are the main plastic materials and they account for 47% of the total plastic demand. As an unavoid- able result of this huge demand, the amount of post consumer plastic waste generated in EU was also rather high: 24.6 million tonnes in 2007. The current fate of these wastes indicates that about 50% of them are recovered and 50% are disposed of in landfills. In addition, within this 50% of recovered waste plastics, about 21% are recycled (mainly by mechanical recycling) while 29% corresponds to energy recovery [1]. There is a steady effort to divert the amount of plastic wastes disposed in landfills, which is driven by the EU Directives. In this regard, the 2008/98/CEE Directive establishes a ∗ Corresponding author. Tel.: +34 91 488 70 88; fax: +34 91 488 70 68. E-mail address: josemaria.escola.saez@urjc.es (J.M. Escola). target of 50% recovery of paper, metal, plastics and glass wastes in 2020 for all the member countries [2] whose enforcement (at least for plastics) is meant to lead towards the development of new technologies to deal with these wastes. Catalytic conversion of polyolefin plastic wastes into fuels over solid acid catalysts is one of the technologies that are receiv- ing increased attention due to the interesting products obtained (gasoline, diesel, fuel, etc.) [3,4]. This fact has led towards the development of several processes at pilot plant scale or even at commercial level [5]. The success of the process depends mostly on the employed catalysts since they allow the working temperature to be decreased and a product having a narrow molecular size distri- bution to be obtained. Owing to this, the number of works studying the performance of different catalysts (zeolites, silica–alumina and mesostructured materials) in the catalytic cracking of poly- olefins is ample [6–20]. From these works, it is concluded that, the need of using catalysts which contain highly accessible acid sites because the bulky nature of the plastic wastes usually leads towards steric hindrances or diffusion constraints e.g. in zeolite micropores. This can be solved by using mesostructured catalysts (Al-MCM- 41, Al-SBA-15) [16,17] with mesopore sizes within 2.0–30.0 nm, nanozeolites with high external surface area (above 100 m 2 g -1 ) 0926-3373/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.apcatb.2011.05.048