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Title: Desenvolvimento de metodologia de extração de cloretos em petróleos por aplicação indireta de ultrassom
Authors: Sad, Cristina Maria dos Santos
Keywords: Ultrassom;Extração de Cloretos;Petróleo;Preparação de Amostras;Ultrasound;Extraction of Chlorides;Oils;Preparing Samples
Issue Date: 4-Dec-2013
Publisher: Universidade Federal do Espírito Santo
Citation: SAD, Cristina Maria dos Santos. Desenvolvimento de metodologia de extração de cloretos em petróleos por aplicação indireta de ultrassom. 2013. 107 f. Dissertação (Mestrado em Mestrado em Química) - Universidade Federal do Espírito Santo, Vitória, 2013.
Abstract: This paper proposes a methodology for extraction of chlorides in oils of 13-36 °API and chloride content of NaCl in the range from 2 to 1070 mg kg- 1 expressed in NaCl, using the technology of ultrasound (US) with the use of organic solvents. Additionally, after optimization of solvent extraction methodology, it was evaluated the extraction efficiency without adding solvents. Relevant factors to the homogenization of the samples, solubility of solvents, performance of demulsifiers, recovery test in a sample fortified with formation water and determination of the concentration of chlorides in crude oil samples were investigated with the goal of developing a robust procedure. The results in recovery tests by US for intermediate and heavy oils showed efficiency above 97% for extraction of chlorides, being more efficient if compared to ASTM D6470 method that was modified with an extraction efficiency of around 90%. The first stage of this work was to determine the conditions for maximum extraction of chlorides in the sample of heavy oil with 16 °API. For this,I t was designed a factorial design highlighting the factors that influence the extraction of chlorides of the samples, such as time and temperature of heating. Once established the conditions, two methodologies were evaluated: extracting salt with the use of solvents (deionized, water, xylene, acetone and isopropyl alcohol) and without the use of solvents (deionized water and commercial demulsifier). The maximum time of extraction without causing formation of stable emulsion with and without solvent was 1 min of ultrasound exposure at a temperature of 80 (± 5) °C in a single extraction step. However, it was found that for some samples with different degrees API and high contents of chloride, subjected to US extraction system (with and without solvent),it was necessary to make three extraction stages (at intervals of 1 min each).To validate the methodology, it was selected 23 samples (interlaboratory program CENPES) of desalted petroleum refining , with °API around 29 and water content less than 0.5%(v/v), where it was evaluated in different extraction methods of chlorides: ASTM D6470 optimized (UFES), US (UFES) , ASTM D6470 (CENPES) and Microwave (UFSM). The quantification techniques used were potentiometric titration and ion chromatography. The potentiometric technique was more effective when applied to samples with a detection limit greater than 5 mg kg- 1NaCl (about the sample). The results of the interlaboratory program evaluated by CENPES showed that the US method (with and without solvent ) showed higher extraction efficiency of chlorides if compared to methods ASTM D6470 (CENPES) and ASTM D6470optimized (UFES).According to CENPES assessment, techniques for extracting salt assisted by US are indicated for oil refining loads
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