Abstract
Oxy-fuel combustion is an attractive way toward low-carbon energy systems and carbon capture and storage (CCS) policy. Its economy largely depends on high-purity oxygen (O2) price. The most commonly used commercial O2 production technologies are cryogenic distillation (ASU), adsorption, and polymeric membrane separation. Pressure swing adsorption (PSA) is suitable for small and medium-sized O2-consuming processes, which may be ideal for pilot-scale oxy-fuel plants. This paper generally investigates the performance of a two-bed four-step commercial PSA oxygen generator, quality and quantity of O2 production, process scheduling, and optimal operating conditions. The air flow rate at ambient temperature and pressure of 8.5 - 11 bar ranged from 13 - 17 m3 (STP)/h throughout the experiments. Furthermore, the textural properties of UOP PSAO2 XP molecular sieve with enhanced N2/O2 selectivity were experimentally determined and an increased presence of micropores was detected. To describe the process, an analytical flow-balance model was developed. This model calculates air factor (AirF), O2 recovery (REC) and purity (PUR), and energy consumption based on the actual gas flow determined for the system, incorporates parameters sensitivity analysis, and verifies the PSA performance. The model was validated under four O2 purity levels with the lowest measurement error. The experimental data obtained showed good agreement with the model results; the controversy surrounding some of the data is discussed. In practice, the application of the validated model provides an easy-to-grasp engineering solution.
