Asphaltenes are a heavy fraction of petroleum with the ability for self-association, a phenomenon that can occur spontaneously in the reservoirs or in any of the various stages of production and processing, depending on variations in pressure, temperature, composition and shearing, among others. In this work, it was evaluated the precipitation of asphaltenes in two oils (P01 and P02) in different conditions of temperature and pressure and in the absence or presence of CO2. Under high pressure and temperature conditions, the precipitation of asphaltenes was observed in the presence of CO2 in mixtures with methane, while the addition of propane induced precipitation in the absence of CO2. The results of analyses elemental (CHNO), SEM, FTIR and LDI-MS were consistent with the structure assigned to samples of this nature (oils, maltenes and fractions of asphaltenes insoluble in n-pentane, C5I, and n-heptane, C7I).
Keywords:
asphaltenes; precipitation; characterization; carbon dioxide; light alkanes
