Simulation and Performance Analysis of a Plateau-Adapted Five-Bed Portable Vacuum Pressure Swing Adsorption Oxygen Production System

To address the decline in oxygen production capacity and the increase in specific energy consumption of portable vacuum pressure swing adsorption (VPSA) oxygen systems under high-altitude low-pressure conditions, a rotary-valve integrated VPSA numerical model based on a five-bed, ten-step cycle was established in this study and analyzed on the Aspen Adsorption platform. The results show that, under a trade-off between oxygen purity and recovery, an oxygen purity of 93.1% and an oxygen recovery of 27.8% can be achieved when the purge-valve flow coefficient is 6.67×10−5kmol/(h·bar). When the product-valve flow coefficient is 0.028mol·s−1·MPa−1 and the altitude increases from 3000 m to 4500 m, the oxygen production rate decreases by about 22%, while the specific energy consumption increases by about 32.4%. This indicates that the reduction in oxygen partial pressure has a significant effect on the separation driving force. As the product-valve flow coefficient increases from 0.010 to 0.037mol·s−1·MPa−1, the oxygen production rate continuously increases and the specific energy consumption decreases at all altitude conditions. At an altitude of 3000 m, for example, the oxygen production rate increases from 0.12m3·h−1 to 0.176m3·h−1, while the specific energy consumption decreases from 3.58MJ·m−3 to 2.93MJ·m−3. The effect of feed flow rate on specific energy consumption shows a trend of first decreasing and then increasing. The minimum energy consumption is obtained in the range of 18–20L/min. These results provide a theoretical basis for parameter matching and energy-efficiency optimization of multi-bed rotary-valve VPSA systems under high-altitude conditions.