Estudo da otimização do método de centrifugação para análise da eficiência na extração de material interfacial em óleo emulsionado caracterizado por FT-ICR MS

• Ano de defesa: 2025
• Autor(a) principal: Souza, Luciara Costa de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Química; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Química
• Palavras-chave em Português: Emulsão; Petróleo; Espectrometria de massa; Centrifugação; Emulsion; Petroleum; Mass spectrometry; Centrifugation; Química
• Link de acesso: http://repositorio.ufes.br/handle/10/19664

Emulsions are common in the oil industry, present in various processes such as extraction, transportation and refining. However, emulsions can present a significant problem in this sector. Understanding the compounds that play a significant role in stabilizing water/oil (W/O) emulsions is crucial to developing effective treatment methods. The isolation and characterization of Interfacial Material (IM) is an attempt to better understand the species involved in the formation and stabilization of emulsions. This study aims to optimize the methodology of Pereira et al. (2014), which is based on centrifuging an emulsion and separating the oily phase from the remaining (unresolved) emulsion. The study aims to investigate the influence of time and temperature in the centrifugation step, in order to obtain the interfacial material. A sample of naturally emulsified oil was centrifuged, initially varying the centrifugation time by 15, 30, 60, 90, 120, 180, 240 minutes, keeping the temperature constant at 60 °C and the rotation at 9500 rpm. The temperature was then varied by 20, 30, 40, 50 and 60 °C, keeping the time constant at 120 minutes and the rotation at 9500 rpm. The centrifugation stage resulted in two fractions (EPS and EPR). These fractions were distilled using Dean-Stark (to remove the water), centrifuged (to remove the salt) and evaporated (to remove the solvent) to obtain the interfacial materials (IMS and IMR) respectively. All samples were analyzed using ESI(-)FT-ICR MS. High-resolution mass spectrometry proved crucial for identifying the chemical species of the oil and its fractions, as well as offering precise insights into the molecular composition of the IMS by identifying the species that contribute to the stability of the emulsion. The analysis indicated that adjusting the centrifugation time and temperature in the IMR and IMS samples resulted in a decrease in nitrogen species (N1[H] class) and an increase in naphthenic acids (ANs or O2), N2[H] species and mixed classes (N1O2[H], N1O3[H], O3[H] and O3S[H]). Notably, highly aromatic molecules with double bond equivalents (DBE) of 4 to 20 migrated from the aqueous phases to the N1O2[H] and N1O3[H] classes. For ANs, there was a migration to the interface mainly of linear (DBE 1) and aromatic (DBE > 11) molecules. The increase in aromaticity of the IMR sample compared to the crude oil emulsion was confirmed by means of Van Krevelen diagrams, where the H/C vs. O/C or N/C ratio showed a decrease in H/C values for NxOy[H], Oy[H] and Nx[H] species, with x = 1-2 and y = 1-3. The application of Principal Component Analysis (PCA) to the MS data allowed the classification of emulsions based on the type of fraction produced by centrifugation MI, EPR, EPS, crude oil and dehydrated crude oil. The main classes of compounds driving the PCA variance for the MI class were N1O1[H], N1O2[H], N1O3[H], O2[H] and O3[H].