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The effects of operating temperature on the performance of small scale oxygen concentrator were experimentally investigated using a rotary valve multi-column rapid cycle pressure swing adsorption (PSA) unit which produced a continuous stream of ≥ 90% O2 from compressed air. Simple cooling fans and air cylinder were used for controlling the temperature of compressed air. The change of column midpoint gas temperature inside adsorption column was relatively small and approximately 3–5 K with a low pressure ratio of ~ 250:101 kPa during each cycle. The oxygen recovery could be improved by increasing the operating temperature and the bed size factor (BSF) could be reduced by decreasing the operating temperature. However, the adverse thermal effects on oxygen recovery and BSF became more dominant at very low and high operating temperatures. A similar trend between unit power and BSF at different operating temperature was emerged. There was an appropriate temperature range for achieving favorable performance. [ABSTRACT FROM AUTHOR]

The rapid pressure swing adsorption (RPSA) technology has been widely used for applications including portable oxygen generators due to high O2 productivities and low bed size factors (BSF, total amount of adsorbent per ton of O2 produced per day, kg/TPDO2). The improvement of RPSA process has been a key issue for efficient O2 production in terms of its generally lower O2 recovery as compared to other processes. In this work, a dual-column RPSA oxygen production system with an intermittent purge step (intermittently switching between purge and interruption) was designed to investigate the effects of interruption frequency (the number of interruptions during a purge step) and times on the O2 recovery, purity, productivity and BSF. Experimental results show the improvement on O2 production performance using the intermittent purge step in comparison to conventional continuous purge step. Under the optimized interruption frequency of 2 and time of 0.3 s, the O2 recovery, purity and productivity were increased from 36 to 39.2%, 89.5 to 93%, and 6.24 to 6.49 mmol/kg/s, respectively, while the BSF was decreased from 57.94 to 55.75 kg/TPDO2. [ABSTRACT FROM AUTHOR]

A novel rapid vacuum pressure swing adsorption process with intermediate gas pressurization for producing oxygen is proposed to improve the performance of miniature oxygen concentrator based rapid pressure swing adsorption technology. The effects of intermediate gas pressurization and desorption pressure on the performance of the process are evaluated by experiments and simulations. Results showed that pressurization with intermediate gas from product end can effectively improve the oxygen purity of the product. The pressure and oxygen purity of intermediate gas before pressurization were key parameters that affected the oxygen purity of the product. When the adsorption pressure was 240 kPa and the desorption pressure was 60 kPa, the test unit for the process produced 0.75 L min of ~90% O with 29.45% of oxygen recovery from compressed air. The minimum bed size factor (BSF) for ~90% O product was 82.84 kg TPD. The BSF could be effectively reduced by lowering the desorption pressure. Moreover, oxygen recovery could be improved by lowering the desorption pressure. [ABSTRACT FROM AUTHOR]