New Pressure Swing Adsorption Cycle Schedules for Producing High-Purity Oxygen Using Carbon Molecular Sieve

Abstract

Two 3-bed 5-step and two 4-bed 7-step continuous feed pressure swing adsorption (PSA) cycle schedules were systematically devised and studied via simulation for producing high-purity O2 (≥99.5 vol %) at high recovery using a carbon molecular sieve (CMS). Two binary (O2:Ar) and two ternary (O2:Ar:N2) feed mixtures were investigated to mimic the product produced from a typical O2 PSA system. In addition to feed composition, the effects of light end (LE) versus heavy end (HE) equalization (Eq), two sequential Eq steps versus Eq followed by forced cocurrent depressurization (CoD)/light end pressurization (LEP) steps, feed flow rate (i.e., feed throughput θ), cycle time (tc), Eq step valve coefficient (Cv), and countercurrent depressurization (CnD) step Cv on the process performance were studied in terms of O2 purity (Pur, vol %), O2 recovery (Rec, %), and θ (LSTP, h/kg). In descending order, the best performance from each cycle was Pur = 99.5, Rec = 93.3, and θ = 455.7 for a 4-bed 7-step PSA cycle with LE Eq ...