High-Pressure CO₂/CH₄ Separation Using SAPO-34 Membranes

Abstract

SAPO-34 membranes on stainless steel, tubular supports separated CO 2 from CH 4 at feed pressures up to 3.1 MPa. The highest CO 2 permeance was 2.4 × 10 -7 mol/(m 2 s Pa) for a 50/50 feed mixture at a pressure drop of 0.14 MPa. For a pressure drop of 3 MPa, the CO 2 /CH 4 separation selectivities at 253 K were 140-150; at lower pressure drops, the highest selectivity was 270. The highest CO 2 flux was 21 kg/(m 2 h) at 295 K and a pressure drop of 3 MPa. Separation selectivity decreased as temperature increased because separation was partly based on competitive adsorption. As transmembrane pressure drop increased, both CO 2 flux and CO 2 permeate concentration increased for a 50/50 mixture. The flux pressure dependence was modeled by Maxwell-Stefan diffusion for mixtures. Methane decreased the CO 2 diffusion rate and, thus, decreased the CO 2 flux. The CH 4 flux was also lower in a mixture because CO 2 inhibits CH 4 adsorption.

Performance of PEI/BMI semi-IPN membranes for separations of various binary gaseous mixtures☆

“…8. The decrease in the CO 2 permeance by increasing CO 2 concentrations in the feed gas mixture was also observed by others [27][28][29]. As the feed pressure is constant at 827 kPa (120 psig) the slight decrease in the permeance might be attributed to the CO 2 adsorption coverage as illustrated elsewhere [27].…”

Energy optimization of bioethanol production via gasification of switchgrass

“…The third process consists of the use of a membrane that is porous to CO 2 . This alternative does not eliminate H 2 S. It requires high pressure and the MEA that is used as a carrier for the CO 2 permeated though the membrane 40 has to be regenerated requiring a large amount of energy. The two different synthetic paths require different gas purities in terms of H 2 S concentration.…”

CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

“…Removal of carbon dioxide from natural gas is extremely important in order to meet the transportation pipeline specifications as well as produce natural gas from associated gas dug out from oil wells [11,13]. The most common adsorbents used in PSA separation processes for carbon dioxide-methane system are inorganic adsorbents like zeolite, activated charcoal, and polymer adsorbents like polysulfone and polyacetate.…”