Effects of Nonisobaric and Isobaric Steps on O2 Pressure Swing Adsorption for an Aerator

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• 作者：Jeong-Geun Jee ; Hae-Jun Park ; Seung-Joo Haam ; and Chang-Ha Lee
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2002
• 出版时间：August 21, 2002
• 年：2002
• 卷：41
• 期：17
• 页码：4383 - 4392
• 全文大小：305K
• 年卷期：v.41,no.17(August 21, 2002)
• ISSN：1520-5045

文摘

The effects of nonisobaric and isobaric steps on a two-bed O₂ pressure swing adsorption (PSA)packed with zeolite 5A were investigated. In addition, the operating conditions in the O₂ PSAwere studied to supply the various O₂ concentrations to the oxygen aerator efficiently. Becausethe velocity variation along the bed and the related Mass Transfer Zone (MTZ) shape at theisobaric and nonisobaric steps were affected by the diffusion rate, the concentration-dependentrate parameter in a modified linear driving force (LDF) model was evaluated from the Darkenequation related to the loading ratio correlation isotherm model. The LDF coefficients had asignificant effect on the prediction of the O₂ purity and recovery at the low flow rate region.However, the higher the feed flow rate, the lower the LDF parameter effect. It was also notedthat the effects of each step time in the isobaric and nonisobaric steps on the PSA performancewere subtle in the O₂ purity and recovery except for the blowdown step. Also, there was theoptimum step time to maximize the O₂ purity and recovery in the adsorption and pressurizationsteps, while the increase of O₂ purity and recovery with the pressurization equalization steptime showed asymptotic curvature. The idle time at the pressurization step had a negative effecton the PSA performance, while the short idle time at the pressure equalization step led toimproved product purity. However, it was negligible for the effect of the idle time at the blowdownstep on the PSA performance. The successive variation between high and low P/F ratios causedthe continuous variation of O₂ purity and recovery to nearly the same extent as the resultsunder each constant P/F ratio condition. Therefore, to save the operating cost of the oxygenaerator system, the desired oxygen concentration for the aerator can be supplied simply bycontrolling the feed rate or purge rate.