Non-additive separation selectivity enhancement in poly(4-methyl-2-pentyne) in relation to C1-C4-alkanes

• Published in: Separation and purification technology 2019-04, Vol.212, p.877-886
• Main Authors: Zhmakin, V., Shalygin, M., Khotimskiy, V., Matson, S., Teplyakov, V.
• Format: Article
• Language: English
• Subjects: C1-C4-alkanes; Membrane separation; Poly(4-methyl-2-pentyne)
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2018.11.086

[Display omitted] •High non-additive butane/methane mixture selectivity values were obtained.•An approach to fast membrane transfer parameters (P, D, S, EP, ED, ΔHS) estimation is developed.•Lower alkanes permeability through PMP is controlled by the diffusion contribution.•Simulation of a binary butane/methane mixture separation demonstrates high performance. This study examines the fundamental and practical aspects of C1-C4 hydrocarbons separation (pure or in binary or ternary mixtures), using highly permeable glassy 1,2-disubstituted polyacetylenes. Poly(4-methyl-2-pentyne) (PMP) was chosen as the main object of study. An attempt is made here to carry out a systematic comparative study of the PMP permeability target parameters using correlation detection and a thermodynamic gas/polymer model. A non-isothermal application method was used, which allowed us to work with each gas individually and with various mixtures to obtain an experimental value for the dependence on temperature of the permeability of C1, C3, C4 hydrocarbons. This is the first time that this method has been used for the study of glassy polymers with high free volume. An interesting phenomenon of an increase in non-additive separation selectivity α was shown (for a value of α of between ∼10 and ∼8000 units) with increase of butane activity (p/psat) from 0.02 to 0.94 in the feed gas mixture. In the current study, an explanation is given for the increase in non-additive selectivity for PMP membrane separation. Modelling was carried out of the separation process of a binary butane/methane mixture using this non-additive phenomenon, which gives rise to concentrated components.