Paper Title
RAPESEED OIL BUTYL ESTERS PRODUCTION USING SNAIL SHELLS AS A HETEROGENEOUS CATALYST

Abstract
Abstract - The transport sector is one of the sectors polluting the environment with greenhouse gases. Environmental concerns and energy security are driving the expansion of electric vehicle use. However, this process is not fast, in the transport sector there are many vehicles using diesel engines. Biodiesel can be used in a mixture with mineral diesel in any ratio. Therefore, replacing at least part of mineral diesel with biodiesel produced from renewable resources would reduce environmental pollution and increase energy independence. Industrially biodiesel is usually produced from oilby transesterification with methanol and the process is accelerated by chemical homogeneous catalysts. However, there are questions regarding the classification of such biodiesel as a fully renewable fuel, since chemical reagents are used in its production process. Therefore, more and more researches investigate application of more environmentally friendly alcohols- ethanol or butanolfor oil transesterification. Butanol has attracted great interest due to good properties of the final product. The application of heterogeneous catalysis in biodiesel synthesis is becoming more popular, biocatalysts or metal oxides and their mixtures are usually used. Heterogeneous catalysis has an advantage of easy separation of the catalyst from the final product. Calcium oxide is known as an efficient catalyst for biodiesel synthesis. Snail shells is a waste rich in calcium compounds, which can be converted to calcium oxide via calcination step. In the present work, optimum conditions for rapeseed oil butyl esters using snail shells as a heterogeneous catalyst were investigated. It is very important to prepare catalyst before using it for transesterification reaction, therefore optimum conditions for catalyst preparation was studied. Optimum catalyst fraction size was obtained 0.315–0.1 mm and calcination temperature 850 °C was used to convert CaCO3 to CaO. It was obtained that calcinated snail shells which we used for rapeseed oil transesterification contained 91.69% of CaO. Transesterification reactions were conducted in laboratory reactors,containing condensers, thermometers with a temperature controllers and a mixers(at a constant mixing speed of 350 min–1). Response surface methodology was employed to determine the optimal reaction conditions. The optimum determinedconditions of butyl esters production were the following: the catalyst amount – 7.53wt%, the molar ratio of methanol to oil – 10.61:1, the reaction duration – 10.77 hours and the reaction temperature – 110 °C. The ester yield obtained was 99.25%, which meet the requirements of the EN 14214 standard for biodiesel.Our findings indicate the potential of snail shells as a heterogeneous catalyst for biodiesel production using butanol.