Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport

Abstract

Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene) was studied within the temperature and pressure ranges of 25–600 °C and 110–160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption–diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

CO2/H2 separation through poly(ionic liquid)–ionic liquid membranes: The effect of multicomponent gas mixtures, temperature and gas feed pressure

“…In multicomponent gas mixture tests, the competitive sorption effect between CO 2 , H 2 and N 2 led to a significant reduction of both CO 2 and H 2 permeabilities compared to those obtained in single gas experiments, as it can be seen from Table 3. This behavior is in agreement to what has been reported in literature for other similar gas mixtures [17,40,46,47]. Concerning the CO 2 /H 2 permselectivities, the PIL C(CN) 3 -60 IL C(CN) 3 membrane shows slightly lower mixed permselectivity (11.4) compared to that obtained in single gas experiments (12.2).…”

Etching gas-sieving nanopores in single-layer graphene with an angstrom precision for high-performance gas mixture separation

“…Gas permeance from M14 (1-s plasma-treated membrane) before and after 150°C treatment used to remove contaminants. References (40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)…”

Numerical Analysis of CO2-to-DME Conversion in a Membrane Microchannel Reactor

“…However, H 2 transport from the permeate zone to the reactive mixture is desired, as it increases the rates of hydrogenation reactions. , These requirements are met satisfactorily by SOD membranes that offer high steam permselectivity to methanol (233), DME (253), and CO 2 (23) and allow H 2 transport along with steam as quantified by a relatively low H 2 O/H 2 selectivity of 4.6 at 473 K. , At this temperature, the permeability of the SOD membrane is reported as 6.8 × 10 –8 mol m –2 s –1 Pa –1 . Owing to the lack of permeability data at the temperatures of the current work (503–543 K) and differences between membrane separation of multicomponent and binary mixtures, with the former being expected to be hindered by phenomena such as competitive adsorption to the membrane surface, , the permeability is taken as 3 × 10 –8 mol m –2 s –1 Pa –1 . This value is justified in the context of the current membrane model (see the Supporting Information, Section F) by means of conducting a series of simulations (Section ) to elucidate the effect of permeability on the molar flow rates of permeating species (H 2 O and H 2 ), CO 2 conversion, and DME yield.…”