Pure - and sour mixed-gas transport properties of 4,4′-methylenebis(2,6-diethylaniline)-based copolyimide membranes

• Published in: Polymer (Guilford) Vol. 166; pp. 184 - 195
• Main Authors: Hayek, Ali, Yahaya, Garba O., Alsamah, Abdulkarim, Alghannam, Afnan A., Jutaily, Sulaiman A., Mokhtari, Ilham
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 12.03.2019; Elsevier BV
• Subjects: 6FDA-Durene/MDEA; Carbon dioxide; Durene; Gas mixtures; Gas permeation; Gas separation; Gas transport; Hydrogen sulfide; Membrane permeability; Membranes; Methane; Permeability; Permeability coefficient; Pressure; Random copolyimide; Selectivity; Selectivity coefficient; Sour gas; Sour mixed-gas; Sweet gas; Transport properties; Sour mixed-gas; 6FDA-Durene/MDEA; Permeability coefficient; Random copolyimide; Selectivity coefficient
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2019.01.056

Three aromatic 6FDA-Durene/MDEA random copolyimides with different Durene:MDEA molar ratios (3:1; 1:1 and 1:3) were synthesized, and pure gas permeation properties through their dense films were investigated. Compared to their corresponding homopolymers (6FDA-MDEA and 6FDA-Durene), the copolymers exhibit significant improvement in gas separation performance, as the membranes display improved gas transport properties. For example, for pure gas, the CO2 permeability for 6FDA-Durene/MDEA (3:1) is around 234 Barrer and CO2/CH4 selectivity equal to 17.8 obtained at 22 °C and feed pressure of 100 psi. In addition, for sweet gas mixture consisting of 10, 59, 30 and 1 vol% CO2, CH4, N2 and C2H6, respectively, the 6FDA-Durene/MDEA (1:3) copolyimide membrane shows CO2 permeability of 73 Barrer and CO2/CH4 selectivity of about 24 at an elevated pressure of 800 psi. For a sour gas mixture with high H2S content (20 vol % H2S in the feed gas), the membrane exhibits H2S/CH4 selectivity of 21; and H2S permeability of 112 Barrer. The transport properties of the herein reported membrane are similar to or even better than the performance exhibited by some polymeric membranes reported in the literature. [Display omitted] •Pure gas permeation properties of three 6FDA-Durene/MDEA copolyimides with different Durene:MDEA molar ratios are reported.•Effect of pressure revealed excellent plasticization resistance up to 300 psi for 6FDA-Durene/MDEA (1:3) at 35 °C.•Sweet mixed-gas permeation showed CO2/CH4 selectivity of 24 with CO2 permeability of 73 Barrer at 800 psi.•Sour mixed-gas permeation showed H2S/CH4 selectivity of 21 with H2S permeability of 112 Barrer at 400 psi.