KINETICS AND THERMODYNAMIC STUDIES ON THE PRODUCTION OF BIODIESEL FROM Balanites Aegyptiaca OIL USING ITS SHELL AS CO-CATALYST

Abstract

Kinetics and thermodynamic studies on the production of biodiesel from Balanites aegyptiaca oil using its shell as co-catalyst was carried out by trans-esterification of the oil with methanol. First the oil was extracted from the seed kernel of Balanites aegyptiaca using a mechanical extractor. The waste fruit shell of the Balanites aegyptiaca was subjected to carbonization process to generate activated carbon which was used as co-catalyst for the trans-esterification to produce the biodiesel. The effects of temperature, time of stirring, ratio of volumes of the reactants, and concentration of the catalyst on the yield of biodiesel were monitored and recorded. The optimum values of the results obtained were used to determine the values of the kinetic and thermodynamic parameters governing the biodiesel production. The biodiesel yield obtained was 72.5%. The kinetic data obtained for the forward reaction could not fit the differential rate law for any of the orders of reaction investigated, but data for the reverse reaction, obtained by mirror-imaging of the forward reaction, followed second order kinetics with rate constant k = 0.017239cm3/min at 303K. The change in entropy, ∆S = 62.4JK-1, heat of reaction, ∆H = 29,207Jmol-1 and energy of activation, Ea = 29,207Jmol-1. The positive value of the ∆H showed the reaction to be endothermic, taking in heat from the surrounding, and due to the large value of the Ea the reaction could not have occurred without the catalyst. It is recommended that further research be carried out to find the reaction order for the forward reaction of the trans-esterification and not finalize conclusion on the order of reaction obtained by mirror image of the process.