Long-term performance of highly selective carbon hollow fiber membranes for biogas upgrading in the presence of H2S and water vapor

Boosting Renewable Methanol Production: A Study on Enriched Hydrogen Recovery Using Hollow Fiber Carbon Membranes in Syngas Stream Upgrades

“…On the other hand, CO 2 permeance was always higher than that measured in single gas and tended to increase as the concentration of H 2 in the feed increased, reaching its highest value when the mixture contained about 80% H 2 . A similar behavior has been observed experimentally and theoretically for zeolite membranes for both H 2 and CO 2 trends. , As already observed in literature, even though permeation through carbon membranes is primarily controlled by diffusion into pores of size comparable with the molecule size, the reduction of H 2 permeance with increasing CO 2 feed molar fraction can be attributed to the hindering effect of CO 2 molecules preferentially adsorbed on the sorption sites of the membrane pores . This creates a “reduction” in the volume available for the diffusion of molecules, resulting in a decrease in the H 2 permeance.…”

“…44,45 As already observed in literature, 36 even though permeation through carbon membranes is primarily controlled by diffusion into pores of size comparable with the molecule size, the reduction of H 2 permeance with increasing CO 2 feed molar fraction can be attributed to the hindering effect of CO 2 molecules preferentially adsorbed on the sorption sites of the membrane pores. 36 This creates a "reduction" in the volume available for the diffusion of molecules, resulting in a decrease in the H 2 permeance. With the increasing of the H 2 feed molar fraction, less CO 2 is present in the feed and thus it easily adsorbs inside the membrane matrix, with a consequent increase in CO 2 diffusivity owing to the reverse of coverage, 46,47 which is dominant over the lower sorption, resulting in an increase in CO 2 permeance.…”

“…This underscores the potential advantages of using carbon membranes in these applications. In our previous work, 36 we have demonstrated the capability of hollow fiber carbon membranes to operate stably also in the presence of contaminants and water vapor for more than 180 days of continuous testing. In this work, carbon hollow fiber membranes were developed to selectively separate H 2 and CO 2 .…”

Recent developments in polysaccharide and lignin-based (nano)materials for CO2 capture

“…In 2022, Brunetti et al continuously exposed cellulose-based carbon hollow fiber membranes to a gas stream, which also contained H 2 S and/or water vapor for 183 days while observing the separation performances of the membranes. 243 At 298 K and 10 bar, CO 2 and CH 4 showed adsorption capacities of 2.98 and 2 mmol g −1 , respectively. Moreover, in 2022, mixed matrix membranes (MMMs) with better CO 2 adsorption capability were prepared by Rehman and colleagues.…”

Analysis of the Techno-Economic Competitiveness of a Three-Stage Membrane Separation Process for Biogas Upgrading Using a Biopolymer-Based Mixed-Matrix Membrane

“…In addition to engineering toolboxes for process systems, combined approaches of materials and process design methods also offer a straightforward link among membrane performance, optimal process structure, and cost. Those studies could be extended to more complex systems, including multicomponent feed compositions, multimembrane systems, or multitarget problems, such as combined biogas upgrading and carbon capture objectives. ,− Significant progress has also been made in the development of membrane materials specifically designed for the separation of CO 2 /CH 4 mixtures from different sources, ranging from advanced polymers, such as thermally rearranged polymers and of intrinsic microporosity to metal–organic frameworks, carbon, silica, and zeolite types, and more recently, biopolymers. , Biopolymer-based membranes evaluated for biogas upgrading include micro- and nanocellulose, PVA blends in nanocomposite membranes, polylactic acid (PLA)-based membranes, , and chitosan (CS)-based membranes and the formulation as mixed-matrix membranes (MMMs). − These biopolymer-based MMMs seem to be sustainable alternatives for CO 2 /CH 4 separation, pending mature development for its further implementation.…”