Avaliação física, química e microbiológica do diesel, biodiesel e suas misturas durante a logística de distribuição

Abstract

Chemical and microbiological degradation reactions in fuels tend to form sediments and sludge in storage tanks and decrease their qualities when applied in vehicles. These degradation products can promote blockages of the atomization valves, for example. This work aimed to verify if there were sediments and sludge formations in the bottom of storage tanks of diesel, biodiesel and their mixtures, characterize physical, chemical and microbial properties of these samples and evaluate if these possible alterations have been passed to their respective supply pump. The collect places were a biodiesel experimental plant, fuel distributor and stations. There were observed that the diesel and biodiesel samples were in accordance with the established by National Agency of Petroleum, Natural Gas and Biofuels (ANP), except for some biodiesel properties from its plant. The oxidative stability by PetroOXY test of the pure diesel (DB0 S500) was greater than B5 S500 > B5 S50 and these are bigger than for biodiesels. The bottom storage tank and the supply pump samples from the plant and the fuel stations showed Candida tropicallis, Aspergillus fumigatus e Klebsiella sp. growth. These microorganisms promoted sediment, oil-water interface and emulsion formations when they were inoculated in sabouraud dextrose broth. The diesel, biodiesel and their mixtures, as the pump as the bottom tank samples, have similar chemical composition when analyzed by gas chromatography coupled with mass spectrometer (GC-MS) and absorption in the infrared (IR) region and they have not been suffered alterations due to the presence of the existent microorganisms.