Thesis Archive
Estimation of Cetane Number from Fatty Acid Methyl Ester Profile of Pure and Binary Algal Cultures as Biodiesel Feedstock (2011)
Airah Jane V. Hernandez
Krizzia I. Torres
Linley G. Vivas
Abstract:
-“Biofuel production can serve as a long term replacement for the depleting fossil fuels as means to reduce greenhouse gas emission and to increase energy supply. One possible feedstock in producing biodiesel is microalgae because of many factors: (a) culturing microalgae is easy because it requires lime attention (b) they have higher growth rates compared to agricultural crops and other aquatic plants (c) They contain more oil than other crops. (d) Microalgae are renewable, carbon neutral and environment friendly. The aim of this study is to estimate the cetane number of the biodiesel that will be produced from each growth phase of the microalgae. Pure cultures and binary mixtures of microalgae were grown and these strains are Anabaena Variabilis. Anabaena Laxa and Hapalosiphon Welwitschii. The growth patterns of these algae were evaluated using the method of chemical oxygen demand and nitrate analysis. The approximate time (exponential phase or stationary phase) of when transesterification will be executed was also determined through these methods. For the stationary phase of the pure icroalgal cultures, direct transesterification was applied twelve days after the start of the culture, while for the binary mixture, it was the eleventh day. For the exponential phase, it was the fourth day for the pure and binary mixture of Anabaena Variabilis and Anabaena Laxa, and the mixture of Anabaena Variabilis and Hapalosiphon Welwitschii. The process of direct transesterification used methanol and an acid catalyst (H2SO4) since microalgae is high in free fatty acid (FFA), which when reacted to a base catalyst can lead to saponification (soap formation). Cetane number was estimated from a correlation available in literature by using the composition of each methyl ester from the fatty acid methyl ester (FAME) profile of the biodiesel that was obtained through gas chromatography. The cetane numbers were estimated from fatty acid profiles using the correlation found in Chapter 2. The cetane numbers of the biodiesel samples from the individual culture of microalgae species Anabaena Laxa, Anabaena Variabllis and Hapalosiphion Welswitschii for the exponential phase were 55.44, 69.29 and 16.12, respectively; whereas for the stationary phase they are 39.69, 11.88 and 9.92, respectively. Also, for the binary mixtures Anabaena Laxa + Anabaena Variabilis, Anabaena laxa + Hapalosiphon Welwitschii and Anabaena Variabilis + Hapalosiphon Welwitschii, the cetane numbers obtained for the biodiesel samples from the exponential phase were 51.02, 65.81 and 66.15 respectively; while for the stationary phase, the cetane numbers were 23.78, 40.72 and 34.32, respectively.”
Adviser:
Mr. Joseph Auresenia
[email protected]