This chapter focuses on the selection of optimum parameters for transesterification of linseed oil biodiesel production in the presence of calcium oxide (CaO) obtained from the waste eggshells. The waste chicken eggshells were calcined at 900°C for 4 hours and it was characterized by X-ray diffractometer (XRD). The transesterification process was conducted according to L9 orthogonal array with selected input control parameters such as methanol to oil molar ratio, reaction temperature, and catalyst loading. The output parameters were biodiesel yield and viscosity. The multi-objective, decision-making technique called Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was used to identify the optimum transesterification process parameters to obtain maximum biodiesel yield with minimal viscosity. The optimized values for transesterification process parameters were depicted as methanol to oil ratio of 6:1, reaction temperature of 65°C, and catalyst loading of 5% w/w.
TopIntroduction
Fossil fuel plays an important role in the transportation sector. Continuous usage of fossil fuel in the automobiles leads to emission of harmful gases like CO, NOx, and HC to the environment (Karthickeyan, Thiyagarajan, et al., 2019; Viswanathan, Balasubramanian, Subramanian, & Varuvel, 2019). Emission of harmful green-house gases leads to global warming (Sandouqa & Al-Hamamre, 2019). On the other hand, continuous usage of fossil fuel leads to extinct of particular resource. Thus, demand for fossil fuel-based resources, emission of greenhouse gases induces the researches to focus on biodiesel (Varun, Singh, Tiwari, Singh, & Kumar, 2017). Biodiesel was eco-friendly, renewable and bio-degradable and non-toxic resource. Biodiesel has 12% of oxygen, this adds further advantage in the context of emissions in diesel engine (Karthickeyan, 2019a). Generally non-edible oil was used for biodiesel production. Transesterification is a chemical process used to reduce the viscosity of the non-edible oil (Pandit & Fulekar, 2017). In the transesterification process, non-edible oil along with alcohol and catalyst was properly mixed and heated at elevated temperature (Karthickeyan, 2019b; Karthickeyan, Ashok, Nanthagopal, Thiyagarajan, & Edwin Geo, 2019). As continuous transfer of heat, triglyceride of non-edible oil was converted into Fatty Acid Methyl Ester (FAME) and this FAME was termed as biodiesel (Sandouqa & Al-Hamamre, 2019). Two category of catalyst was widely used in the transesterification process, namely homogeneous and heterogeneous catalyst. Homogeneous catalyst has its own drawbacks as multi washing of transesterified oil was required to remove catalyst residues and also produces unwanted waste water which then creates excess soap by-product. Homogeneous catalyst was not reusable and corrosive to equipment. Heterogeneous catalyst overcomes homogeneous catalysts drawbacks. Homogeneous solid catalyst was easy to recover and reusable for several times and excess wastewater production was eliminated (Mansir, Hwa Teo, Lokman Ibrahim, & Yun Hin, 2017).
Generally, all catalyst produces its impact on environmental concerns. Therefore, development of solid catalyst has recently gained much attention among the researchers to overcome the aforementioned issues. In this regard a waste eggshell catalyst is a potential source for producing low cost biodiesel. Waste eggshell contains high amount of calcium components (CaCO3) and this CaCO3 could be easily converted to Calcium Oxide (CaO) by calcinations method. Calcined CaO is a potential catalyst as it is cheap, non corrosive, eco-friendly and reusable (Tan, Abdullah, & Nolasco-Hipolito, 2015).