Byline: Hulya Karabas, Semra Boran and Harun Resit Yazgan
Summary: There is a growing recognition that using of biodiesel in large commercial systems based on sustainability, existing resources and residues can help to natural resources. Tobacco seed oil (TSO) is also used for biodiesel production as a non-edible vegetable oil. A crude oil was obtained from tobacco seeds (TS) and then tobacco seed oil methyl ester-TSOME (biodiesel) was obtained by a transesterification process. In this study, we aimed to achieve optimal biodiesel properties based on different factors using multi response Taguchi method and multivariate analysis o f variance (MANOVA). The purpose of the process was to meet a European Biodiesel Standard EN 14214. Properties of the biodiesel (responses) were determined as methyl ester quantity, kinematic viscosity, density, flash point of methyl ester and freezing point of methyl ester.
The factors (production parameters) were chosen such as catalyst type, alcohol/oil molar ratio, reaction temperature and catalyst amount for experiment design. The factors that influenced the desired properties were determined using MANOVA. The factors' level was obtained using a multi response Taguchi method. We found that catalyst type and catalyst amount have a significant effect on the responses and their levels must be level 1(KOH) and level 3 (1.5%) respectively. Thereby the method s provided to produce biodiesel meet requirements of the standard with minimum cost and in short time.
Key words: Tobacco seed oil, Biodiesel, Optimization, Multi response Taguchi method, Multivariate analysis of variance (MANOVA)
Biodiesel is an alternative renewable and biodegradable fuel with properties similar to petroleum diesel. Scarcity of traditional petroleum fuels, its over-dependence by nations, increasing emissions of combustion-generated pollutants and their increasing costs have made renewable energy sources more attractive. Currently, biodiesel is mainly prepared from conventionally grown edible oils such as rapeseed, soybean, sunflower and palm thus leading to alleviate food versus fuel issue [1-3]. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. The use of non-edible plant oils when compared with edible oils is very significant in developing countries because of the tremendous demand for edible oils as food which are too expensive to be used as fuel at present.
Biodiesel is made up of fourteen different types of fatty acids, which are transformed into fatty acid methyl esters (FAME) by transesterification [4, 5]. Different fractions of each type of FAME in various feedstocks influence some properties of fuels. Vegetable oil is converted into biodiesel through a chemical process that produces methyl or ethyl ester. Commonly used alkali catalysts are potassium hydroxide (KOH) or sodium hydroxide (NaOH).
Alkali-catalyzed transesterification is much faster than acid-catalyzed reaction [6, 7]. The chemical process is called transesterification which produces biodiesel and glycerin.
In this study, TSO was chosen in order to produce a biodiesel. The oil extraction process from tobacco seed and transesterification process for biodiesel production were considered. Hence, in biodiesel production in this study, the multi response Taguchi method developed by Tong et al.  and MANOVA were...