Avaliação de metodologia de purificação da glicerina gerada como coproduto na produção de biodiesel

Abstract

Biofuels of biomass for some time has reached a prominent role in the world energy matrix, particularly to reduce dependence on fossil fuels. Among them, there is biodiesel from the transesterification reaction of a triglyceride with a short chair alcohol. As the reaction products are obtained methyl or ethyl esters (biodiesel) and glycerin. Focusing on preserving the environment, the adoption of biodiesel, even if gradually, the petroleum diesel will result in a significant reduction in emissions of particulates, sulfur compounds, nitrogen and gases that contribute to the greenhouse effect. This recovery of growth biofuels generated in production of biodiesel and consequently a high amount of glycerin produced (about 10% of the total production) without a destination defined by the producing plants. The major obstacle of using this coproduct is purity. The glycerin from the transesterification has about 20% impurity, the main ones being: the catalyst used, alcohol, fatty acids and water. When purified glycerol product can be used in the chemical, pharmaceutical, and cosmetic (purity 99.5%). The transesterification reaction of soybean oil was performed in the laboratory. Glycerin obtained underwent hydrolysis with an acid phosphoric acid, for the purpose of reacting with the soaps present to form free fatty acids and also to neutralize the catalyst. Subsequently, different basic salts were tested for the neutralization of coproduct seeking remove excess phosphoric acid used in the hydrolysis. The salt that is more efficient for the process Na2CO3 was 75 ° C. Finally different adsorbent materials were tested as attapulgite and activated carbon, varying the concentration in respect of glycerin (% m / m) and time. Simultaneously they were carried distillation vacuum (single and fractionated) The adsorbent material which has proved most effective has been activated carbon, which was obtained a 93% glycerol content for the first purification and 98% for the second purification, showing that may be an alternative for the purification of glycerol obtained from the transesterification reaction. The characterization of the obtained samples was carried out by Infrared Spectroscopy, since the quantification of samples by spectrophotometry in the UV-Vis at 410 nm.