Four-Bed Pressure Swing Adsorption for Oxygen Separation from Air with Zeolite 13X

This article is presented an experimental and modeling study of a four-bed pressure swing adsorption process using zeolite13X to provide oxygen-enriched air. The binary mixture N2/O2 (79/21 vol %) was used as a feed stream. The effects of purge/feed ratio (P/F), adsorption pressure, adsorption time and product flow rate on product purity under nonisothermal condition were studied. The higher the P/F ratio, the faster decreasing the purity during long adsorption times. In a constant pressure, for long adsorption times the purity is decreasing significantly in high P/F ratios (0.18≤ P/F ≤ 0.24). In a constant P/F ratio and pressure, increasing the product flow rate causes gentle decreasing of purity. Pressure changes have not significant effect on purity. In cycle time 140 S, P/F ratio = 0.18, pressure = 4 bar, product flow rate = 0.4 lit/min, the purity of 96.22% is achieved. In this study, the sorption rate into an adsorbent pellet is described by the liner driving force (LDF) model with a single lumped mass-transfer parameter. A mathlab code using finite difference method was developed to solve the set of coupled differential-algebraic equations, and the simulation results are agreed well with experimental results.

Keywords:

Zeolite 13X , Air Separation , Pressure Swing Adsorption