Termodinâmica do equilíbrio de fases no sistema condensado de gás natural (c5+) - água produzida

• Ano de defesa: 2010
• Autor(a) principal: Almeida, Sheyla dos Santos
• Orientador(a): Marques, José Jailton
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Sergipe
• Programa de Pós-Graduação: Pós-Graduação em Engenharia Química
• País: BR
• Palavras-chave em Português: Água produzida; UNIFAC; Eletrólitos; Condensado de gás natural
• Palavras-chave em Inglês: Produced water; UNIFAC; Electrolytes; Natural gas condensate
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA
• Link de acesso: https://ri.ufs.br/handle/riufs/5061

Produced water is one of the main wastes generated in oil exploration and its treatment is a challenge due to its complex composition and the great amount generated. Regarding to the environmental legislation concerning to disposal, it is important to create alternatives of reuse or treatment, in order to reduce its contaminant content and decrease the hazardous effects to the environment. In spite of the fact that some techniques to treat this wastewater are already in use, other actions can be done to improve the quality of separation processes, decrease oil losses and protect the environment. Extraction is a physical separation method in which a solvent is added to perform the separation of residual oil that is the objective of this study. Due to the high availability of natural gas condensate (C5+) in gas processing plants, this product was chosen to be used as the solvent in the extraction of residual oil from produced water, emulsified or not, once there is a good chemical affinity between the oil fractions and the added solvent. At first, a bibliographic survey was carried out to find a predictive model for electrolytes without the need of experimental data. A computational program was developed in FORTRAN, taking in account the group-contribution method in the presence of electrolytes, besides isothermal flash. Some adaptations were implemented at Kikic et al. (1991) model to get a good agreement with the system studied. This system took in account light hydrocarbons present in oil (pentane, hexane, heptane and octane) and strong electrolytes, which is mainly represented by NaCl. The validation of thermodynamics model showed satisfactory medium quadratic deviations when compared to real experimental systems. A pseudo-experimental planning was carried out to simulate the process and verify the influence of the studied variables on the proposed system, such as solvent and salt contents, temperature and BSW (Basic Sediment and Water). Through the obtained empirical model it was possible to check the influence of the factors on residual hydrocarbons contents, represented by TPH (Total Petroleum Hydrocarbon). Temperature and solvent content were the variables that more contributed to increase TPH, while salinity contributed to the decrease TPH in the aqueous phase. The simulations performed showed that the use of C5+ is a feasible alternative to recover residual oil fractions from produced water and oily sludges. The contributions of this work motivate future studies, mainly those that involve experiments related to this theme, regarding to evaluate the quality of the adapted model, decreasing significantly oil losses during the steps of oil production and primary processing, providing information to reduce environmental impacts of these activities.