Modelagem numérica da absorção e dessorção de CO2 em água usando OpenFOAM

• Ano de defesa: 2021
• Autor(a) principal: Souza, Marlon Lemos de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Engenharia Mecânica; Centro Tecnológico; UFES; Programa de Pós-Graduação em Engenharia Mecânica
• Palavras-chave em Português: Absorção; desorção; DFC; escoamento multifásico; modelagem matemática; subject.br-rjbn; Engenharia Mecânica
• Link de acesso: http://repositorio.ufes.br/handle/10/15341

Salt fouling of carbonate origin is one of the main problems related to the flow guarantee in oil production environment and its formation is mainly caused by concentration change of CO2(g) in the medium, contributing between 60% to 90% of the total precipitated content according to Cosmo (2013). With that in mind, this work aims to use CFD to analyze through simulations the CO2(g) absorption and desorption mechanisms in pure water and estimate the saturation concentration, volumetric mass transfer coefficient (ks,ia) and residence time. Two scenarios were built in the OpenFOAM v.1912 environment: a rectangular bubble column (w=0.15 m x h=0.50 m) and a horizontal pipe (L = 30 m; ∅=12.7 mm) with constant gas mass flow, the first being evaluated in a pressure range between 5 and 50 bar and considered both absorption and desorption mechanism by pressure drop and the second of 25 to 50 bar only for the absorption mechanism and both submitted to T=293K. The solubility of CO2(g) in water under known thermodynamic conditions was obtained in order to validate the Henry’s Law application. The numerical results were compared with the Diamond and Ankinfiev (2003) model showing agreement between the values, with a maximum relative error (RE) of 0.41%. The CO2(g) concentration curve in water in the bubble column was constructed and compared with the theoretical model of the CO2(g) absorption dynamics in water developed by Tokumura (2007), where both curves showed a similar behavior with a maximum residual error of 24.91% between the numerical and theoretical models in relation to the ks,ia. The ks,ia for the deficit injection case in the horizontal pipeline were collected and compared with the study by Jepsen (1979), with relative errors within the range of 15.00%. OpenFOAM was shown to be able to solve mass transfer problems involving gas absorption and desorption mechanisms and is accurate in predicting values of ks,ia and saturation concentration, where the results of ks,ia is correlated with the superficial gas velocity and energy dissipation and provided a good fit for the theoretical data from bubble columns (RE<25%) and in pipelines (RE<15%) and the solubility is directly proportional to pressure.