Pressure swing adsorption process for the separation of nitrogen and propylene with a MOF adsorbent MIL-100(Fe)

The recovery of propylene and nitrogen from the stream formed during the resin degassing (70% N2/30% C3H6) within the polypropylene production process is important from the economic and environmental points of view. This work proposes the use of a pressure swing adsorption process with MIL-100(Fe) as an adsorbent to carry out this separation, either for recovering only nitrogen, or recovering both nitrogen and propylene. Single and binary breakthrough curves were experimentally determined on a lab-scale set-up and simulated to validate the mathematical model. PSA simulation results showed that for the nitrogen recovery process, a product purity of 99.9% and a recovery of 81.5% could be achieved with a power consumption of only 115 Wh/kgN2. For the nitrogen and propylene recovery process, the products purities obtained were respectively 99.9% for nitrogen and 97.9% for propylene with recoveries of 97.4% and 87.6%. The adsorbent productivity was 0.20 kgN2/kgads/h and 0.07 kgC3H6/kgads/h. The total power consumption increased to 179 W h/kgN2 or 309 W h/kgC3H6 a value that is still below the ones reported previously in the literature for other technologies.