Propylene/propane separation by vacuum swing adsorption using 13X zeolite

A vacuum swing adsorption process using 13X zeolite pellets with five steps was designed to split an equimolar mixture of propylene/propane: pressurization with feed; high‐pressure feed; high‐pressure purge with product; cocurrent blowdown; and counter‐current vacuum blowdown, where the enriched propylene product is withdrawn. In the process, the partial pressure of the C 3 ‐mixture is controlled with nitrogen, which is used as inert gas. With an equimolar feed of C 3 diluted to 50% with nitrogen, the column is fed at 5 bar and 423 K, and the product is obtained when the total pressure is lowered to 0.1 bar. After 15–20 cycles, the cyclic steady‐state condition is achieved, a propylene‐enriched stream of 98% mol relative to propylene/propane mixture, with 3.2% of nitrogen, a recovery of 19% (molar basis), and a productivity of 0.785 mol/kg·h is obtained. The experimental work was complemented with numerical simulations, and the effect of different operating parameters on the performance of the VSA was considered.