AIChE Journal, Vol.47, No.2, 341-357, 2001
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purge with product; cocurrent blowdown; and counter-current vacuum blowdown, where the enriched propylene product is withdrawn.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.