Pyrolysis of grape bagasse: Effect of pyrolysis conditions on the product yields and characterization of the liquid product _ Ilknur Demiral ⇑ , Emine Aslı Ayan Department of Chemical Engineering, Faculty of Engineering and Architecture, Eskis ßehir Osmangazi University, Mes ßelik Campus, 26480 Eskis ßehir, Turkey article info Article history: Received 8 September 2010 Received in revised form 16 November 2010 Accepted 17 November 2010 Available online 23 November 2010 Keywords: Grape bagasse Pyrolysis Bio-oil Characterization abstract In this study, pyrolysis of grape bagasse was investigated with the aim to study the product distribution and their chemical compositions and to identify optimum process conditions for maximizing the bio-oil yield. Particular investigated process variables were temperature (350–600 °C), heating rate (10–50 °C/min) and nitrogen gas flow rate (50–200 cm 3 /min). The maximum oil yield of 27.60% was obtained at the final pyrolysis temperature of 550 °C, sweeping gas flow rate of 100 cm 3 /min and heating rate of 50 °C/min in a fixed-bed reactor. The elemental analysis and heating value of the bio-oils were determined, and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques such as column chromatography, 1 H NMR and FTIR. The fuel properties of the bio-oil such as flash point, viscosity and density were also determined. The bio-oils obtained from grape bagasse were presented as an environmentally friendly feedstock candidate for bio-fuels. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction The increasing fuel costs, limited fuel sources and environmen- tal considerations are the most significant causes of the require- ments for studies on the alternative renewable energy sources. Biomass is a primary candidate because it is the only renewable source of fixed carbon, which is essential in the production of con- ventional hydrocarbon liquid transportation fuels and many con- sumer goods (Efendi et al., 2008). The utilization of biomass as a renewable energy resource is of great importance in responding to concerns over the protection of the environment and the security of energy supply (Xu et al., 2009). Like other biomass wastes, agricultural wastes contain a high amount of organic constituents (cellulose, hemicellulose, lig- nin and minor amounts of other organics) and possess a high en- ergy content (Tsai et al., 2006; Kim et al., 2010). Therefore, its conversion to renewable energy would be attractive since it would solve pollution problems, reduce greenhouse gases emissions and provide a clean fuel with low sulfur content. Conversion of biomass to energy is undertaken using two main process technologies: thermochemical and biochemical/biological. Pyrolysis is one of the primary thermochemical conversion meth- ods to convert biomass into valuable products namely; solid prod- ucts (char, charcoal), liquid products (wood tar, tar, oil, pyrolytic oil) and gas products (wood gas, pyrolytic gas). The major products of biological conversion processes are biogas, hydrogen and ethanol (Horne et al., 1996; Özçimen and Ersoy-Meriçboyu, 2008). The bio-oil contains hundreds of organic compounds that be- long to alkanes, aromatic hydrocarbons, phenol derivatives and little amounts of ketones, esters, ethers, sugars, amines and alco- hols with H/C molar ratio higher than 1.5 (Wu et al., 2009; Qiang et al., 2009). Bio-oils can be used for the production of chemicals (food flavorings, resins, fertilizers and emission control agents) and substituted for fuel–oils in many stationary applications for heat or electricity generation (boilers, furnaces, engines and tur- bines) (Uzun and Sarıog ˘lu, 2009). Their direct use as conventional fuels may present some difficulties due to their high viscosity, poor heating value, corrosiveness and instability (Vitolo et al., 1999; Zhang et al., 2005). Consequently, research has been directed to upgrading the oils by catalytic treatment to produce a derived fuel product with a similar quality to a refined petroleum fuel (Williams and Nugranad, 2000). The solid product (char) is useful as a renewable fuel or for other applications such as metallurgical and leisure industries, soil amender and the production of activated carbon and biocarbon electrodes (Bridgwater, 1990; Karaosmanog ˘lu et al., 1999; Di Blasi, 2008). The gases which con- sist mainly of hydrogen, carbon dioxide, carbon monoxide, ethane, propane and methane have a low to medium heating value but may contain sufficient energy to supply the energy requirements of a pyrolysis plant (Horne and Williams, 1996; Li and Zhang, 2005). Grape is a non-climacteric fruit that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or used for making jam, juice, jelly, vinegar, wine, grape seed 0960-8524/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2010.11.077 ⇑ Corresponding author. Tel.: +90 222 2393750/3663; fax: +90 222 2393613. E-mail address: idemiral@ogu.edu.tr ( _ I. Demiral). Bioresource Technology 102 (2011) 3946–3951 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech