OLEFIN PARAFFIN SEPARATIONS BY ADSORPTION - PI-COMPLEXATION VS. KINETIC SEPARATION/

Monolayer dispersed AgNO3 on silica gel was prepared by thermal disper sion. This sorbent exhibited superior adsorption properties for olefin /paraffin separations by selective adsorption of olefins through pi-co mplexation. This sorbent, along the Ag+ ion-exchanged resin, was subje cted to simulation studies for olefin/paraffin separations by pressure -swing adsorption. Kinetic separations (due to differences in olefin/p araffin diffusivities) using zeolite 4A and molecular-sieve carbon wer e also studied. Using 50/50 mixtures of C2H4/C2H6 and C3H6/C3H8, separ ations using these sorbents were compared directly based on olefin pro duct purity, recovery, and throughput. The monolayer AgNO3/SiO2 sorben t showed superior separation results for C3H6/C3H8, and the Ag+-exchan ged resin showed best results for C2H4/C2H6. In both cases, over 99% p roduct purities could be obtained at reasonably high recoveries and th roughputs. For C3H6/C3H8 separation on AgNO3/SiO2, multiplicity of cyc lic steady states were observed within certain regions of feed and pur ge velocities. Within these regions, two stable cyclic steady states w ere reached starting from different initial-bed conditions while all o perating conditions were identical.