Efeito da estrutura química, temperatura e pressão na permeabilidade de CO2 e seletividade CO2/CH4 em filmes formados por dispersões aquosas de poli(uretano-uréia)s

• Autor(a) principal: Bittencourt, Paula Perfeito
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12066
• topic: CO2/CH4 separation; gas Permeation; aqueous dispersions of poly(urethane-urea); poly(ethylene glycol); structure/properties relations; operational conditions; Separação CO2/CH4; permeação de gases; dispersões aquosas de poli(uretano ureia)s; poli(glicol etilênico); relações estrutura/propriedade; condições de operação; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA::TECNOLOGIA QUIMICA::POLIMEROS

Membrane gas permeation have been presented as an alternative process for the removal of CO2 from natural gas on production platforms, mainly in the Brazilian Pre-Salt scenario, but the process still faces challenges due to the limited performance presented by available commercial membranes. Recently, films based on aqueous dispersions of poly(urethane-urea) (PUU) have shown promising results, but the influence of temperature, pressure and PUU structure still needs to be evaluated. In this work, films formed by aqueous dispersions of poly (urethane-urea)s, based on isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), ethylenediamine (EDA), triethylamine (TEA) and polyol containing a mass fraction of 25% poly (propylene glycol) (PPG) and 75% Block copolymer based on PPG and poly (ethylene glycol) (PEG) were prepared, characterized and evaluated in pure CO2 and CH4 permeation assays. As reference (PUU Base), an NCO/OH formulation of 1.5 and 7% (mass) of PEG in the copolymer was used. From the PUU Base, the influence of the PEG content on the formulation was evaluated using another copolymer containing 17% (mass) of this oligomer (PUU 1), while the influence of the ratio between rigid and flexible segments was evaluated by increasing the NCO/OH ratio for 2.0 (PUU 2). The films were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) in order to identify the structural changes caused by the modifications in the formulation and its impacts on the transport properties. Another objective of the present work was to evaluate the influence of the operating conditions on CO2 permeability and CO2/CH4 selectivity in the formed films. Thus, permeation tests were conducted at two temperatures (35 °C and 45 °C) and three transmembrane pressures (1, 2 and 4 bar). The increase in temperature promoted increased permeabilities, while pressure variation led to two different effects on each material. The increase in the PEG content (PUU 1) did not represent gains in the separation performance, while the increase in the NCO/OH (PUU 2) ratio presented more promising results