Olefin/paraffin separations by adsorption: π‐Complexation vs. kinetic separation

Abstract Monolayer dispersed AgNO 3 on silica gel was prepared by thermal dispersion. This sorbent exhibited superior adsorption properties for olefin/parafin separations by selective adsorption of olefins through π‐complexation. This sorbent, along with Ag + ion‐exchanged resin, was subjected to simulation studies for olefin/parafin separations by pressure‐swing adsorption. Kinetic separations (due to differences in olefin/parafin diffusivities) using zeolite 4A and molecular‐sieve carbon were also studied, Using 50/50 mixtures of C 2 H 4 /C 2 H 6 and C 3 H 6 /C 3 H 8 , separations using these sorbents were compared directly based on olefin product purity, recoveiy, and throughput. The monolayer AgNO 3 /SiO 2 sorbent showed superior separation results for C 3 H 4 /C 3 H 8 , and the Ag + ‐exchanged resin showed best results for C 2 H 4 /C 2 H 6 . In both cases, over 99% product purities could be obtained at reasonably high recoveries and throughputs. For C 3 H 6 /C 3 H 6 separation on AgNO 3 /SiO 2 , multiplicity of cyclic steady states were observed within certain regions of feed and purge velocities. within these regions, two stable cyclic steady states were reached starting ffom different initial‐bed conditions while all operating conditions were identical.