INVESTIGATION OF PROCESS YIELD IN THE TRANSESTERIFICATION OF COCONUT OIL WITH HETEROGENEOUS CALCIUM OXIDE CATALYST J. M. Velasquez, K. S. Jhun, B. Bugay, L. F. Razon 1 and R. R. Tan 2 Chemical Engineering Department De La Salle University 2401 Taft Avenue, 1004 Manila, Philippines E-mail: 1 luis.razon@dlsu.edu.ph and 2 raymond.tan@dlsu.edu.ph ABSTRACT The commercial success of biodiesels has to date been limited by high production costs of vegetable oil methyl esters. High feedstock costs are compounded by side reactions such as soap formation during conversion using conventional catalysts, and the consequent costs of product refining and purification. Recent studies on the heterogeneous catalysis of the transesterification reaction with commercial ion exchange resins have met with some success; the findings suggest that use of heterogeneous catalyst improves yield compared to conventional processing with homogeneous acid or alkaline catalyst. This study investigated the performance of heterogeneous calcium oxide catalyst in the production of coconut methyl ester. Specifically, the study investigated the effect of temperature, time, excess methanol and catalyst to oil ratio on conversion of oil in batch reactions as well as the level of trace calcium in the final product using a two-level factorial experimental design. The tests achieved conversion levels of 91.5 – 95.7%, based on measured TG levels of 0.6 – 1.2%. The specific gravity of the biodiesel phase was also found to be in the range of 0.83 – 0.87, which is also indicative of high conversion. Only temperature was found to have a statistically significant effect on triglyceride conversion, which implies that the overall rate of reaction is controlled by surface reaction kinetics rather than mass transfer. On the other hand, none of the experimental factors were found to have a statistically significant effect on the level of calcium contamination of the biodiesel product. Keywords: Biodiesel; Calcium Oxide; Heterogeneous Catalyst 1.0 INTRODUCTION Many countries have started to implement measures to reduce adverse impacts on their economies through energy efficiency and alternative fuel programs. The transportation sector has been affected more than other sectors due to its heavy dependence on petroleum products. Alternative fuels such as biodiesel have been proposed as substitutes to reduce the vulnerability of net oil importers. In addition, such fuels are expected to yield significant environmental benefits such as the reduction of emissions of greenhouse gases and air pollutants. Potential feedstocks for biodiesel include soya oil, rapeseed oil, coconut oil, palm oil, and jatropha oil, with the choice being dependent on the region. Biodiesel is now available commercially in limited quantities, but its acceptance has been hindered due to its high cost as well as feedstock supply limitations. Global production of vegetable and marine oils in recent years was about 100 million t/a [1], which is mostly dedicated to traditional uses. Sharma and Singh [2] estimate the combined biodiesel potential of the top ten producing countries in the world at about 40 × 10 9 l/a, with production costs ranging from US$0.5 – 1.7/l; significantly, they list three Southeast Asian countries among the top ten: Malaysia, Indonesia and the Philippines. In terms of volume, soya and palm oil have the largest potential, while other vegetable oils such as corn and coconut oil are available in smaller quantities. Non- traditional feedstocks such as Jatropha curcas and oil-bearing algae are also the subject of much research interest [1-6]. With currently available raw materials and process technology, the main reasons for the high cost of biodiesel are: • Absence of economies of scale in the emerging biofuels industry; • High feedstock costs; • Side-reactions, such as the saponification reaction, leading to feedstock losses and increased utility demands for product refining. Improvements in process technology can potentially address the third factor. In principle, vegetable oils can be converted into biodiesels that closely approximate the properties of petroleum diesel by means of transesterification reactions. Theoretical details are discussed in the next section. By far the most commonly used means of making transesterification reactions proceed at commercially useful rates is through the use of alkali catalysts such as NaOH [1-5]. Their main drawback is that they react with naturally occurring free fatty acids to form soaps, which contaminate the methyl ester product and thus require subsequent (Date received: 29.4.2009) Journal - The Institution of Engineers, Malaysia (Vol. 70, No.4, December 2009) 19 019-024•Investigation of Profcess Yield 5pp.indd 19 1/21/2010 9:44:11 AM