Browsing by Author "Makwaya, Nyaso"

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    Biodiesel production from spirogyra and cucurbita pepo species a case study from Lake Victoria and Mafinga
    (University of Dar es Salaam, 2014) Makwaya, Nyaso
    Although biodiesel is a renewable energy source, it has got a challenge to some of its feedstock as they compete with human foods. In this study, two species of algae and pumpkin seed were identified as alternative sources of biodiesel which do not interfere with human foods, namely Cucurbita pepo sp from Mafinga district and Spirogyra species from Lake Victoria. The experimental results for Spirogyra sp oil show a viscosity of 90 mm2/s, which is higher compared with other biodiesel feedstocks and ASTM D6751 standard, Spirogyra oil has 29% FFA which based on palmitic acid with 23% fatty acid and the oil yield of about 5% by weight. Oil from Cucurbita pepo sp was extracted by hydraulic press machine at operating pressure of 187.45 bar. The oil has low FFA (0.7%), based on oleic acid, which is reasonable for alkali transesterification, viscosity of 50 mm2/s and 36% oil content. A single factor design was used to analyse the influence of the four process variables, namely, Cucurbita pepo oil to methanol (wt/vol) ratio, catalyst concentration, the reaction temperature, and the reaction time, on the transesterification of pumpkin oil. Based on the experimental analysis, the optimal conditions for this process are reported as: Cucurbita pepo oil to methanol (wt/vol) ratio of around 6:1, catalyst concentration of 1.5 wt/wt%, reaction temperature and time of about 50oC, and 90 minutes respectively. The oil was chemically converted via an alkaline transesteriļ¬cation reaction with methanol to methyl esters, with a yield of 75 wt%. Cucurbita pepo oil is a promising source for biodiesel production since most of the characteristics of the biodiesel produced are within ASTM D6751 standard for biodiesel.