Membranes for olefin–paraffin separation: An industrial perspective

In the next decade, separation science will be an important research topic in addressing complex challenges like reducing carbon footprint, lowering energy cost, and making industrial processes simpler. In industrial chemical processes, particularly in petrochemical operations, separation and product refining steps are responsible for up to 30% of energy use and 30% of the capital cost. Membranes and adsorption technologies are being actively studied as alternative and partial replacement opportunities for the state-of-the-art cryogenic distillation systems. This paper provides an industrial perspective on the application of membranes in industrial petrochemical cracker operations. A gas separation performance figure of merit for propylene/propane separation for different classes of materials ranging from inorganic, carbon, polymeric, and facilitated transport membranes is also reported. An in-house–developed model provided insights into the importance of operational parameters on the overall membrane design.

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Hyperaging Tuning of a Carbon Molecular‐Sieve Hollow Fiber Membrane with Extraordinary Gas‐Separation Performance and Stability

Angewandte Chemie International Edition ◽

10.1002/anie.201904913 ◽

2019 ◽

Vol 58 (34) ◽

pp. 11700-11703 ◽

Cited By ~ 9

Author(s):

Wulin Qiu ◽

Justin Vaughn ◽

Gongping Liu ◽

Liren Xu ◽

Mark Brayden ◽

...

Keyword(s):

Gas Separation ◽

Hollow Fiber ◽

Molecular Sieve ◽

Hollow Fiber Membrane ◽

Separation Performance ◽

Fiber Membrane ◽

Carbon Molecular Sieve ◽

Gas Separation Performance

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3D Metal–Organic Frameworks Based on Co(II) and Bithiophendicarboxylate: Synthesis, Crystal Structures, Gas Adsorption, and Magnetic Properties

Molecules ◽

10.3390/molecules26051269 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1269

Author(s):

Vadim A. Dubskikh ◽

Anna A. Lysova ◽

Denis G. Samsonenko ◽

Alexander N. Lavrov ◽

Konstantin A. Kovalenko ◽

...

Keyword(s):

Room Temperature ◽

Gas Adsorption ◽

Magnetic Moments ◽

Bet Surface Area ◽

Separation Performance ◽

Bridging Ligands ◽

Magnetization Data ◽

Metal Organic ◽

Ch4 Adsorption ◽

Gas Separation Performance

Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc2−) [Co3(btdc)3(bpy)2]·4DMF, 1; [Co3(btdc)3(pz)(dmf)2]·4DMF·1.5H2O, 2; [Co3(btdc)3(dmf)4]∙2DMF∙2H2O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co3(RCOO)6}, connected either by btdc2– ligands (1, 3) or by both btdc2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N2, O2, CO, CO2, CH4 adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m2⋅g−1 and promising gas separation performance with selectivity factors up to 35.7 for CO2/N2, 45.4 for CO2/O2, 20.8 for CO2/CO, and 4.8 for CO2/CH4. The molar magnetic susceptibilities χp(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μeff (300 K) ≈ 4.93 μB. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2.

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The spirobichroman-based polyimides with different side groups: from structure–property relationships to chain packing and gas transport performance

RSC Advances ◽

10.1039/d0ra10113c ◽

2021 ◽

Vol 11 (9) ◽

pp. 5086-5095

Author(s):

Shuli Wang ◽

Xiaohua Tong ◽

Chunbo Wang ◽

Xiaocui Han ◽

Sizhuo Jin ◽

...

Keyword(s):

Dihedral Angle ◽

Gas Separation ◽

Gas Transport ◽

Critical Role ◽

Polymer Membranes ◽

Separation Performance ◽

Structure Property ◽

Chain Packing ◽

Structure Property Relationships ◽

Gas Separation Performance

Effect of substituents on the dihedral angle and chain packing plays a critical role in the enhancement in the gas separation performance of polymer membranes.

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Design and Gas Separation Performance of Imidazolium Poly(ILs) Containing Multivalent Imidazolium Fillers and Crosslinking Agents

Polymers ◽

10.3390/polym13091388 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1388

Author(s):

Kathryn E. O’Harra ◽

Emily M. DeVriese ◽

Erika M. Turflinger ◽

Danielle M. Noll ◽

Jason E. Bara

Keyword(s):

Small Molecules ◽

Crosslinking Agent ◽

Gas Permeation ◽

Polymeric Matrix ◽

Separation Performance ◽

Ionic Polymers ◽

Co2 Solubility ◽

Imidazolium Cations ◽

Crosslinking Agents ◽

Gas Separation Performance

This work introduces a series of vinyl-imidazolium-based polyelectrolyte composites, which were structurally modified via impregnation with multivalent imidazolium-benzene ionic liquids (ILs) or crosslinked with novel cationic crosslinkers which possess internal imidazolium cations and vinylimidazolium cations at the periphery. A set of eight [C4vim][Tf2N]-based membranes were prepared via UV-initiated free radical polymerization, including four composites containing di-, tri-, tetra-, and hexa-imidazolium benzene ILs and four crosslinked derivatives which utilized tri- and tetra- vinylimidazolium benzene crosslinking agents. Structural and functional characterizations were performed, and pure gas permeation data were collected to better understand the effects of “free” ILs dispersed in the polymeric matrix versus integrated ionic crosslinks on the transport behaviors of these thin films. These imidazolium PIL:IL composites exhibited moderately high CO2 permeabilities (~20–40 Barrer), a 4–7× increase relative to corresponding neat PIL, with excellent selectivities against N2 or CH4. The addition of imidazolium-benzene fillers with increased imidazolium content were shown to correspondingly enhance CO2 solubility (di- < tri- < tetra- < hexa-), with the [C4vim][Tf2N]: [Hexa(Im+)Benz ][Tf2N] composite showing the highest CO2 permeability (PCO2 = 38.4 Barrer), while maintaining modest selectivities (αCO2/CH4 = 20.2, αCO2/N2 = 23.6). Additionally, these metrics were similarly improved with the integration of more ionic content bonded to the polymeric matrix; increased PCO2 with increased wt% of the tri- and tetra-vinylimidazolium benzene crosslinking agent was observed. This study demonstrates the intriguing interactions and effects of ionic additives or crosslinkers within a PIL matrix, revealing the potential for the tuning of the properties and transport behaviors of ionic polymers using ionic liquid-inspired small molecules.

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