International Journal of Science and Research (IJSR) ISSN: 2319-7064 SJIF (2020): 7.803 Volume 10 Issue 5, May 2021 www.ijsr.net Licensed Under Creative Commons Attribution CC BY Pyrolysis of Sour Cherry Kernels: Physicochemical Characterization of Pyrolysis Oil in Blends of Diesel and n-butanol Arif Hakan Yalçın 1 , İbrahim Mutlu 2 Department of Automotive Engineering, Faculty of Technology, Afyon Kocatepe University, 03200 Afyonkarahisar, Turkey * Corresponding author. Address: Sultandağı Vocational School, Afyon Kocatepe University, 03900, Afyonkarahisar, Turkey E-mail address: ahyalcin[at]aku.edu.tr Abstract: Switching from conventional fuels to alternative renewable biofuels offers the possibility of significant reductions in the pollutant emissions of diesel engines. Biofuel can be obtained from biomass through pyrolysis. Although pyrolysis oil (PO) is a suitable alternative biofuel for diesel engines, the direct use of PO in diesel engine is limited due to its insufficient properties. To improve the properties of PO, it can be blended with conventional diesel using n-butanol as a co-solvent. In this study, PO was produced from sour cherry kernels (SCPO) by pyrolysis at optimum operating conditions which were: 450 °C temperature, 0.5 L/min gas flow rate, 10 °C/min heating rate, 15 min residence time and particle size as broken kernels. SCPO was blended with diesel using n-butanol. The miscibility of the blends was assessed by evaluating their homogeneity after 48 hours. The physicochemical properties of SCPO and the blends were measured. Results showed that it was possible to create homogeneous blends of SCPO and diesel using n-butanol. Blends showed reduced density, kinematic viscosity and water content, and increased cetane number, pH and calorific value as compared to SCPO. We concluded that diesel/SCPO/n-butanol blends could be a potential biofuel source for diesel engine applications. Keywords: Sour cherry, pyrolysis oil, diesel, homogeneity, characterization 1. Introduction The replacement of conventional petroleum-based fuels has been of particular interest as the problems of air pollution, global warming, and fossil fuel depletion have become relevant in recent years. To overcome these problems, the development and application of alternative biofuels derived from biomass is essential. Bio-oil or pyrolysis oil (PO) is a clean, sustainable and renewable energy resource derived from biomass [1], [2]. Recent research highlighted the potential of PO as renewable biofuel for internal combustion engine applications [3], [4]. Use of PO as alternative biofuel has grown recently due to its positive effect in diminishing exhaust gas emissions and sustainability [5]–[9]. Among the various types of biofuels, PO derived from sour cherry kernels has been of particular interest as a substitute for conventional petroleum-based fuels, especially in countries with abundant sources of sour cherries [10]. PO can be produced from biomass by pyrolysis, whereby biomass is decomposed at an oxygen- free, high temperature condition generating vapours which after cooling and condensing, leads to a dark liquid referred as PO [11]. The fuel compositions and properties of PO vary with the biomass feedstock and the operating conditions of pyrolysis [7], [12]. Direct use of PO in a diesel engine is limited because of its poor properties, including a low cetane number, low calorific value (lower heating value; LHV), high kinematic viscosity, high acidity (pH 2-3), and high-water content [5]– [8]. Several approaches have been tested to improve the inadequate properties of PO for use in conventional automotive diesel engines [5]–[8], [13]–[20]. The most viable method is to blend PO with conventional hydrocarbon fuels, such as diesel to physically upgrade the fuel properties of PO for reliable combustion in conventional diesel engines [8], [14], [15], [17], [18], [21]– [25]. However, the miscibility of PO with all conventional hydrocarbon fuels has been a problem due to differences in polarities and densities forming an unstable mixture whereby phase separation occurs after a short period of time [5], [7], [8], [20]. Therefore, an additive is required for the miscibility of PO with conventional hydrocarbon fuels. According to Alcala and Bridgwater, the use of alcohol as an organic solvent allows the miscibility and formation of stable blends over a long time period. They showed that the type and quantity of alcohol used is crucial for blend formation and stability. Using n-butanol gave the widest selection of homogenous stable blends when mixed with PO and bio-diesel [19]. Furthermore, n-butanol has a higher calorific value and better auto-ignitability than ethanol [26]. Therefore, we selected n-butanol as a blend component from among the other alcohol candidates for mixing sour cherry kernel pyrolysis oil (SCPO) with diesel. N-butanol has a kinematic viscosity of 2.2 mm 2 /s which is quite similar to the kinematic viscosity value of 2.7 mm 2 /s for diesel and can effectively lower the viscosity of the blended fuel [8]. N-butanol can dissolve solid particles in PO and suppress the formation of gummy polymers that is produced by polymerization of tar, thereby improving the fuel properties of PO, engine performance and emission characteristics [5], [19], [27], [28]. Few studies have been performed on the pyrolysis of sour cherries [29]. However, no study has been reported on the physicochemical characteristics of SCPO and its usability as an alternative biofuel in compression-ignition (CI) or diesel engines. In this study, pyrolysis of sour cherry kernels was performed whereby the effect of pyrolysis parameters such Paper ID: SR21514205659 DOI: 10.21275/SR21514205659 666