Estudo do processo de produção de biodiesel utilizando óxido de cálcio obtido dos resíduos de conchas de ostras

Abstract

Biodiesel is a renewable fuel derived from vegetable oils or animal fat that can replace entirely or partially the diesel fuel derived from oil. It has some advantages when compared to fossil diesel, such as biodegradability and non-toxicity. The transesterification with a short chain alcohol and basic catalyst is the most usual form of this fuel production. Nowadays, industrial processes use homogeneous catalysts in their processes. However, heterogeneous catalysts have emerged as promising for the production of biodiesel, because they are environmentally friendly and can be regenerated and reused. Besides that, the heterogeneous catalysis makes the production of biodiesel cheaper. The solids derived from natural sources emerge as heterogeneous catalysts, such as oyster shell, due to its low cost and its facility to achieve high catalytic efficiency in transesterification reaction for producing biodiesel. In this context, the aim of this work is the synthesis, characterization and application of a heterogeneous catalyst derived from oyster shell in the transesterification reaction of sunflower oil with methanol, aiming at the production of biodiesel. The natural solid material was thermally modified, obtaining calcium oxide, which plays high catalytic activity. The thermal modification occurred at 900 ºC for three hours in a muffle furnace. The catalyst was characterized X-ray diffraction (XRD), X-ray fluorescence (XRF) and distribution of particle sizes. In order to optimize the biodiesel production, a study of the process variables that influences the transesterification reaction was conducted through a 12 experiments experimental planning. The variables studied were: catalyst concentration (1 %, 2 % e 3 %) and molar ratio oil: methanol (1:6, 1:9 e 1:12). The optimized conditions of reaction were XRM (1:9 mol: mol) and XCAT (2% wt.%.) With production of 99.99% (± 0.04 wt) methyl sunflower biodiesel. In the present work, the evaluation parameter was the conversion into biodiesel, determined by gas chromatography.