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Superglassy polymers have emerged as potential membrane materials for several gas separation applications, including acid gas removal from natural gas. Despite the superior performance shown at laboratory scale, their use at industrial scale is hampered by their large drop in gas permeability over time due to physical aging. Several strategies are proposed in the literature to prevent loss of performance, the incorporation of fillers being a successful approach. In this work, we provide a comprehensive economic study on the application of superglassy membranes in a hybrid membrane/amine process for natural gas sweetening. The hybrid process is compared with the more traditional stand-alone amine-absorption technique for a range of membrane gas separation properties (CO2 permeance and CO2/CH4 selectivity), and recommendations for long-term membrane performance are made. These recommendations can drive future research on producing mixed matrix membranes (MMMs) of superglassy polymers with anti-aging properties (i.e., target permeance and selectivity is maintained over time), as thin film nanocomposite membranes (TFNs). For the selected natural gas composition of 28% of acid gas content (8% CO2 and 20% H2S), we have found that a CO2 permeance of 200 GPU and a CO2/CH4 selectivity of 16 is an optimal target.
Ahmed W. Ameen; Peter M. Budd; Patricia Gorgojo. Superglassy Polymers to Treat Natural Gas by Hybrid Membrane/Amine Processes: Can Fillers Help? Membranes 2020, 10, 413 .
AMA StyleAhmed W. Ameen, Peter M. Budd, Patricia Gorgojo. Superglassy Polymers to Treat Natural Gas by Hybrid Membrane/Amine Processes: Can Fillers Help? Membranes. 2020; 10 (12):413.
Chicago/Turabian StyleAhmed W. Ameen; Peter M. Budd; Patricia Gorgojo. 2020. "Superglassy Polymers to Treat Natural Gas by Hybrid Membrane/Amine Processes: Can Fillers Help?" Membranes 10, no. 12: 413.
Adsorptive separation is a promising alternative to the energy-intensive cryogenic distillation process for separating the ethane/ethylene (C2H6/C2H4) mixtures. Herein, two pillared-layer metal-organic frameworks (MOFs), Ni(HBTC)(bipy) and Ni2(HBTC)2(bipy)0.6(dabco)1.4, are prepared as the C2H6-selective adsorbents for C2H4 purification from C2H6/C2H4 mixtures. The effect of the type of pillars on the framework structure, thermal and moisture stability, as well as the C2H6 and C2H4 adsorption propertiy, of the MOFs was studied. The use of the longer pillars (i.e. bipy versus dabco) to scafolld the Ni(HBTC) improved the pore size (5.5 Å versus 5.3 Å), specific surface area (1474 m2/g versus 1070 m2/g) and moisture stability in the relative humidity range of 0–90%, but compromised the thermal stability (267 °C versus 278 °C). Both MOFs were C2H6-selective, which was evidencd by the single component adsorption experiments using C2H6 and C2H4. The ideal adsorbed solution theory (IAST) selectivity for C2H6/C2H4 mixtures (1:1 and 1:15, v/v) is in the range of 1.4–1.7 at 25–50 °C and 0–1 bar. The preferential adsorption towards C2H6 over C2H4 on both MOFs is then explained by the isosteric heat of adsorption. Additionally, Ni(HBTC)(bipy) also shows the best capacity of up to 6.6 mmol/g for C2H6 adsorption in comparison with other C2H6-selective MOFs at 25 °C and 1 bar. Both MOFs showed the excellent recyclability, with the negligible reduction in the gas uptake observed during four cycles of adsorption/desorption tests. Besides, breakthrough experiments demonstrated that both MOFs can achieve efficient separation of an equimolar C2H6/C2H4 mixture. The findings suggest that Ni(HBTC)(bipy) and Ni2(HBTC)2(bipy)0.6(dabco)1.4 can be further considered as C2H6-trapping adsorbents for the C2H6/C2H4 separation applications in practice.
Huan Xiang; Yan Shao; Ahmed Ameen; Huanhao Chen; Weiting Yang; Patricia Gorgojo; Flor R. Siperstein; Xiaolei Fan; Qinhe Pan. Adsorptive separation of C2H6/C2H4 on metal-organic frameworks (MOFs) with pillared-layer structures. Separation and Purification Technology 2020, 242, 116819 .
AMA StyleHuan Xiang, Yan Shao, Ahmed Ameen, Huanhao Chen, Weiting Yang, Patricia Gorgojo, Flor R. Siperstein, Xiaolei Fan, Qinhe Pan. Adsorptive separation of C2H6/C2H4 on metal-organic frameworks (MOFs) with pillared-layer structures. Separation and Purification Technology. 2020; 242 ():116819.
Chicago/Turabian StyleHuan Xiang; Yan Shao; Ahmed Ameen; Huanhao Chen; Weiting Yang; Patricia Gorgojo; Flor R. Siperstein; Xiaolei Fan; Qinhe Pan. 2020. "Adsorptive separation of C2H6/C2H4 on metal-organic frameworks (MOFs) with pillared-layer structures." Separation and Purification Technology 242, no. : 116819.
Adsorptive separation of ethylene/ethane (C2H4/C2H6) binary mixture has growing interest in petrochemical industries compared to the conventional energy-intensive cryogenic distillation. Development of moisture-stable materials with high selectivity is of great importance to accomplish C2H4/C2H6 separation. Coordination pillared-layer metal-organic framework (CPL-MOF) CPL-2 was synthesised at room temperature, and then modified by silver ions impregnation to enhance the selectivity towards ethylene over ethane. The synthesised CPL-2 and Ag/CPL-2 MOFs have excellent moisture stability which was confirmed by the dynamic water vapour adsorption analysis under 90% relative humidity, showing no significant framework decomposition, even at 50 °C. The calculated selectivity based on gravimetric single-component gas adsorption experiments shows the significantly improved C2H4/C2H6 selectivity from 1.4 to 26.1 after loading 10 wt.% (theoretical) of silver ions on CPL-2. Breakthrough experiments for C2H4/C2H6 (1:1, v/v) mixture suggest that both CPL-2 and 10 wt.% Ag/CPL-2 can achieve the binary mixture separation, and 10 wt.% Ag/CPL-2 shows relatively better dynamic separation performance compared to parent CPL-2. The good adsorption selectivity and moisture stability allow CPL-MOF to be a class of promising porous materials for further exploitation in the separation of C2H4/C2H6 mixtures. Additionally, the method presented here can potentially be extended to other CPLs with different pore sizes for alkene/alkane separations.
Huan Xiang; Ahmed Ameen; Jin Shang; Yilai Jiao; Patricia Gorgojo; Flor R. Siperstein; Xiaolei Fan. Synthesis and modification of moisture-stable coordination pillared-layer metal-organic framework (CPL-MOF) CPL-2 for ethylene/ethane separation. Microporous and Mesoporous Materials 2019, 293, 109784 .
AMA StyleHuan Xiang, Ahmed Ameen, Jin Shang, Yilai Jiao, Patricia Gorgojo, Flor R. Siperstein, Xiaolei Fan. Synthesis and modification of moisture-stable coordination pillared-layer metal-organic framework (CPL-MOF) CPL-2 for ethylene/ethane separation. Microporous and Mesoporous Materials. 2019; 293 ():109784.
Chicago/Turabian StyleHuan Xiang; Ahmed Ameen; Jin Shang; Yilai Jiao; Patricia Gorgojo; Flor R. Siperstein; Xiaolei Fan. 2019. "Synthesis and modification of moisture-stable coordination pillared-layer metal-organic framework (CPL-MOF) CPL-2 for ethylene/ethane separation." Microporous and Mesoporous Materials 293, no. : 109784.
The application of three-dimensional (3D) pillared-layer metal-organic frameworks (MOFs) M(bdc)(ted)0.5 (M = Co, Cu, Ni, Zn) in the adsorptive separation of ethane/ethylene (C2H6/C2H4) mixtures was studied. The effect of the type of metals in M(bdc)(ted)0.5 on the framework structure regarding the moisture stability and adsorption performance was investigated. M(bdc)(ted)0.5 MOFs show excellent porous structures with high surface areas of up to 1905 m2/g (M = Ni), as well as being stable under humid conditions (assessed by the dynamic water vapour adsorption tests with maximum 20% relative humidity at 25 °C). M(bdc)(ted)0.5 exhibits the preferential adsorption of C2H6 over C2H4 under all conditions (i.e. 25–50 °C and 0–10 bar), although a reversal in adsorption uptake (i.e. C2H4 adsorption uptake exceeds the amount adsorbed of C2H6) occurs at pressures of >6 bar. The adsorption capacities of C2H6 and C2H4 on M(bdc)(ted)0.5 adsorbents are up to 8.63 and 8.79 mmol/g at 25 °C and 10 bar, respectively. The calculated C2H6/C2H4 selectivity for an equimolar mixture is insensitive to the metal ions in M(bdc)(ted)0.5, which varies between 1.4 and 1.9. Dynamic breakthrough experiments show that C2H6/C2H4 mixture can be separated in a fixed bed packed with Ni(bdc)(ted)0.5. The good adsorption capacity and selectivity, as well as the low isosteric heat of adsorption, make M(bdc)(ted)0.5 MOFs, especially Ni(bdc)(ted)0.5, good candidates to be further developed for the effective separation of C2H6/C2H4 mixtures in the presence of water vapour with a relative humidity lower than 30%.
Huan Xiang; Ahmed Ameen; Patricia Gorgojo; Flor R. Siperstein; Stuart M. Holmes; Xiaolei Fan. Selective adsorption of ethane over ethylene on M(bdc)(ted)0.5 (M = Co, Cu, Ni, Zn) metal-organic frameworks (MOFs). Microporous and Mesoporous Materials 2019, 292, 109724 .
AMA StyleHuan Xiang, Ahmed Ameen, Patricia Gorgojo, Flor R. Siperstein, Stuart M. Holmes, Xiaolei Fan. Selective adsorption of ethane over ethylene on M(bdc)(ted)0.5 (M = Co, Cu, Ni, Zn) metal-organic frameworks (MOFs). Microporous and Mesoporous Materials. 2019; 292 ():109724.
Chicago/Turabian StyleHuan Xiang; Ahmed Ameen; Patricia Gorgojo; Flor R. Siperstein; Stuart M. Holmes; Xiaolei Fan. 2019. "Selective adsorption of ethane over ethylene on M(bdc)(ted)0.5 (M = Co, Cu, Ni, Zn) metal-organic frameworks (MOFs)." Microporous and Mesoporous Materials 292, no. : 109724.
Permeation properties of pure and gas mixture consisting of CO2, H2S, CH4, N2 and C2H6 through dense films of the block co-polyimides (6FDA-mPDA)-(6FDA-durene) are studied at 35 – 55°C and pressures of 100-500 psi for combined separation of CO2, H2S and N2 from acid gas streams. The H2S composition in the gas mixture is up to 20 vol.%. This rigid block copolymer exhibits relatively constant or slightly decrease in pure gas permeability with increasing feed pressure for most of the penetrants. The pure gas CO2/CH4 and N2/CH4 selectivities are up to 61 and 2.6 respectively. The mixed gas studies also show relatively constant or slightly decrease in permeability coefficients with increase in pressure for most of the penetrants. One significant fact is that, at feed pressure of 500 psi and 20 vol.% H2S in feed gas mixture (consisting of CO2, N2, CH4 and H2S), H2S/CH4 and CO2/CH4 separation factors are 23 and 27 respectively. These values are within the same order of magnitude or even better than those obtained in other state-of-the-art polymeric membranes that have been reported. Another unique feature of this co-polyimide is that, in addition to being selective to acid gas, it is also more selective to N2 as compare to CH4. Moreover, the CO2/CH4 separation factor does not suffer significant loss to the same degree as in the case of cellulose acetate (CA), even under these much more aggressive environments. This stability at moderate pressures and high H2S concentration is quite remarkable, as most reported studies are focused on low H2S concentrations and low pressures.
Garba O. Yahaya; Mohammad AlQahtani; Abdulaziz Alammar; Ahmad A. Bahamdan; Ahmed W. Ameen; Rashed H. Alhajry; Melhan M. Ben Sultan; Feras Hamad. Aromatic block co-polyimide membranes for sour gas feed separations. Chemical Engineering Journal 2016, 304, 1020 -1030.
AMA StyleGarba O. Yahaya, Mohammad AlQahtani, Abdulaziz Alammar, Ahmad A. Bahamdan, Ahmed W. Ameen, Rashed H. Alhajry, Melhan M. Ben Sultan, Feras Hamad. Aromatic block co-polyimide membranes for sour gas feed separations. Chemical Engineering Journal. 2016; 304 ():1020-1030.
Chicago/Turabian StyleGarba O. Yahaya; Mohammad AlQahtani; Abdulaziz Alammar; Ahmad A. Bahamdan; Ahmed W. Ameen; Rashed H. Alhajry; Melhan M. Ben Sultan; Feras Hamad. 2016. "Aromatic block co-polyimide membranes for sour gas feed separations." Chemical Engineering Journal 304, no. : 1020-1030.
A series of aromatic random and multiblock co-polyimides with varying block length was prepared from 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride with m-phenylenediamine (6FDA-mPDA) and 2,3,5,6-tetramethyl-1,4-phenylenediamine (6FDA-durene). The permeability coefficients of pure gases (CO2, CH4, N2, He, O2, and H2) through the multiblock co-polyimide (6FDA-mPDA)-(6FDA-durene) membrane measured at various feed pressure (100–300 psi) and temperature (35 °C) were studied. The temperature dependence of permeabilities was also investigated over the permeation test range of 35–55 °C at 200 psi upstream pressure. The permeability properties of quaternary gas mixtures consisting of 10, 59, 30 and 1 vol% CO2, CH4, N2 and C2H6 respectively through the membrane were investigated at various feed pressures. In pure gas studies, permeability coefficients of all the penetrants stay relatively constant with increasing pressure. Different behaviour was however exhibited in the quaternary gas mixture studies as the permeability values of CO2 decrease with increasing feed pressure, whereas those of CH4, N2, C2H6 increase with increasing feed pressure. Unlike the pure gas studies that show constant CO2/CH4 and N2/CH4 selectivity values as a function of the feed pressure, the mixed gas studies did show some efficiency losses through a decrease of both CO2/CH4 and N2/CH4 selectivity. However C2H6/CH4 separation factor increases rapidly as the feed pressure is further increased.
R. Heck; Mohammad AlQahtani; Garba O. Yahaya; I. Tanis; David Brown; Ahmad A. Bahamdan; Ahmad W. Ameen; M.M. Vaidya; J.-P.R. Ballaguet; R.H. Alhajry; E. Espuche; R. Mercier. Block copolyimide membranes for pure- and mixed-gas separation. Separation and Purification Technology 2016, 173, 183 -192.
AMA StyleR. Heck, Mohammad AlQahtani, Garba O. Yahaya, I. Tanis, David Brown, Ahmad A. Bahamdan, Ahmad W. Ameen, M.M. Vaidya, J.-P.R. Ballaguet, R.H. Alhajry, E. Espuche, R. Mercier. Block copolyimide membranes for pure- and mixed-gas separation. Separation and Purification Technology. 2016; 173 ():183-192.
Chicago/Turabian StyleR. Heck; Mohammad AlQahtani; Garba O. Yahaya; I. Tanis; David Brown; Ahmad A. Bahamdan; Ahmad W. Ameen; M.M. Vaidya; J.-P.R. Ballaguet; R.H. Alhajry; E. Espuche; R. Mercier. 2016. "Block copolyimide membranes for pure- and mixed-gas separation." Separation and Purification Technology 173, no. : 183-192.