Extração assistida por radiação micro-ondas para a remoção de água, sal e sedimentos de petróleo e posterior caracterização

Abstract

In this work a process for simultaneous removal of water, salt and sediments from oil emulsions using microwave radiation (MW) in a closed system was proposed for further characterization of the oil phase. A real oil emulsions containing different amounts of water, salt and sediments was used. The proposed procedure is based on demulsification using water and heating by MW in closed vessels. After this treatment, the oil phase was subjected to centrifugation step and parameters as the microwave power, heating time, sample mass and the number of extraction steps were evaluated. Characterization of crude oil regarding to the water content, salt and sediment was performed before and after the application of MW in order to verify the efficiency of the proposed procedure. Additionally, total acid number (TAN), density (°API), viscosity (mPa s), sulfur and nitrogen were determined after the microwave radiation extraction step. The best conditions obtained with the MW extraction procedure were: 1400 W of MW power, 5 min of heating, 20 g of sample and six successive centrifugation steps. Sediment characterization showed NaCl as the main constituent and 50% of solid materials presented average particle diameter of approximately 22 μm. In addition to the presence of carbonate, sediments have showed the presence of clusters of spherical solid material. By using the proposed procedure a sediment removal efficiency higher than 95% was obtained for three oil emulsions evaluated. In addition, water content in the oil phase was below 1% and the salt content was reduced to values lower than 22 mg g-1, allowing further oil characterization. It was verified a high efficiency removal of interferences such as water, salt and sediments allowing the characterization of crude oil samples.