Preliminary experimental study on biofuel production by deoxygenation of Jatropha oil Max Romero a, ⁎, Andrea Pizzi b , Giuseppe Toscano b , Alessandro A. Casazza a , Guido Busca a , Barbara Bosio a , Elisabetta Arato a a DICCA, Department of Civil, Chemical and Environmental Engineering, University of Genoa, Via Opera Pia, 15, 16145 Genoa, Italy b D3A, Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Via Brecce Bianche 10, 60131 Ancona, Italy abstract article info Article history: Received 24 January 2015 Received in revised form 30 March 2015 Accepted 2 April 2015 Available online xxxx Keywords: Jatropha oil Decarboxylation Hydrotalcite Hydrocarbon biofuel Deoxygenation through decarboxylation of Jatropha curcas (non-edible) oil under a nitrogen atmosphere was performed using alumina (Puralox SBa200) and hydrotalcite (Pural MG70) as catalysts at 350 and 400 °C. In general, liquid product yields obtained exceeded 80%. FTIR spectroscopy showed that the oxygen contained in the liquid product decreases significantly when hydrotalcite is used as the catalyst with a reaction time of 6 h. At the end of the tests, a liquid biofuel was produced with a high proportion of hydrocarbons – around 83% – of mainly C8–C18. The product also showed good properties as a heating value of around 44 MJ/kg, higher than biodiesel (40 MJ/kg) and near to diesel (46 MJ/kg), and a lower viscosity (4 cSt) than biodiesel (4.5 cSt). Using GC analysis it was possible to identify the CO 2 and CO as the principal compounds present in the reaction gas, confirming that oxygen is removed mainly through decarboxylation and decarbonylation reactions. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Over the years, different strategies are being considered to mitigate the impact of greenhouse gases. Among them, the production of liquid biofuels without causing limitation to agro-food production represents an important approach. In fact, the European Union introduced direc- tives 2003/30/EC, 2009/28/EC and 2014/94/EU with the aim of increas- ing biofuel utilization in the transport sector. Vegetable oils are considered important raw material in the produc- tion of biofuels due to their capacity to store large amounts of energy, this capacity is directly related to their chemical structure (e.g. triglycer- ides have similar carbon chains to the carbon chains of the liquid fuels derived from fossil sources). However, vegetable oils also contain oxy- gen atoms incorporated in the form of carboxyl or carbonyl groups. Many properties of the vegetable oils such as high viscosity, high flash point and low heating value compared to fuels as diesel or gasoil are attributed to their chemical structures and oxygen content [1,2]. Pyrolysis of vegetable oils at medium temperatures allows the production of hydrocarbon biofuels [3]. Pyrolysis of different raw mate- rial under atmospheric pressure and temperatures ranging between 350 °C and 550 °C was reported: soybean, palm, and castor oils [4], palm oil over alumina catalyst [5], several animal (lamb, poultry and swine) fatty wastes [6] and the effects of oil type on products obtained in the presence of zeolite catalysts [7]. Also, the non-isothermal kinetics of Jatropha oil pyrolysis using thermogravimetric analysis was studied [8]. As well as the use of very acidic catalytic materials such as protonic zeolites has been the object of several tests, although, the use of milder acidic materials as catalysts seems to be more convenient to produce liquid fuels in the diesel range [9–11]. Conventional pyrolysis is associ- ated with the promotion of C–O cleavages and poor selectivity due to uncontrollable reactions such as cracking or polymerization of the hy- drocarbons, resulting as product a type of biofuel with a high amount of oxygenated compounds as unreacted carboxylic acids, acrolein and ketones [1,6,12]. On the other hand in the transesterification process, C–O cleavages are achieved using catalysts and an alcohol as co-reactant to produce fatty acid methyl esters (biodiesel) [13,14], but this product results to be also a oxygenated biofuel (fuel quality directive 2009/30/EC has limited the use of biodiesel to maximum 7 vol.%). Additionally, the co- production of impure glycerol is a strong drawback of this technology. Recently, processes as catalytic hydrotreating (carried out under similar conditions to those normally used for hydrotreating in oil refin- eries) were used to obtain free-oxygen biofuels from vegetable oils. If followed by mild hydrocracking to improve cold properties, the biofuel produced using this technology was demonstrated to have almost iden- tical properties to normal petrochemical diesel [15]. Literature reports the reaction pathways of the catalytic hydrotreating of soybean oil using different catalysts (Ni, Pd, CoMoS x , and NiMoS x ) for various tem- peratures, hydrogen pressures, and reaction times [16]. Also, different Fuel Processing Technology 137 (2015) 31–37 ⁎ Corresponding author at: University of Genoa — DICCA, Via Opera Pia 15, 16145 Genova, Italy. Tel.: +39 010 3532560. E-mail address: maxrr_1@hotmail.com (M. Romero). http://dx.doi.org/10.1016/j.fuproc.2015.04.002 0378-3820/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Fuel Processing Technology journal homepage: www.elsevier.com/locate/fuproc