New sorbents for enhanced gas separation via pi-complexation: Synthesis, characterization and tailoring of sorbents for the separation of olefins from paraffin

In this study several sorbents were developed for use in a pressure swing adsorption (PSA)-type separation process for the production of high purity olefins. The resulting process would bypass the need for cryogenic distillation columns in this separation. The sorbents developed were based on weak chemical complexation (pi-complexation). For each specific application, several methods of tailoring pi-complexation-capable sorbents were developed. Using these methods, several sorbents were synthesized for the removal of diolefinic compounds from normal alpha olefins and for the separation of C2, C 3 and C4 olefins from paraffins. The success of this study can be measured by comparing the sorbents developed against the performance of existing commercial processes. Currently, the only successful commercial process for olefin-paraffin separation by adsorption is the PETROFIN process developed by BOC with 4A zeolite as the sorbent. It was demonstrated that the sorbents developed in this study can accomplish substantially better separations as compared with PETROFIN when used in a cyclic adsorption process, such as PSA. The results reported in this work demonstrate the feasibility of using adsorption to replace the energy-intensive cryogenic distillation for olefin-paraffin separations in certain low to medium throughput applications such as polyolefin production.