Dual-Bed Pressure Swing Adsorption Processes with New Compact Flat-Box Adsorbers

• Main Authors: Wei-Tzung Chen, 陳韋綜
• Other Authors: Cheng-tung Chou
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/qusfh6

碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 94 === Pressure swing adsorption (PSA) is a cyclic process used for separation of gas mixtures. This process uses variation of pressure as the main operating parameter to achieve separation and is becoming increasingly popular for the production of oxygen or nitrogen from air. The heat released during gas adsorption will increase the bed temperature, which is an unfavorable to adsorption. On the other hand, gas desorption is an endothermic process and the decrease of temperature caused by desorption is unfavorable to desorption. In this study, the traditional cylindrical adsorbers are replaced by flat-box adsorbers, which are stacked together. We hope this design can reach higher performance of PSA by letting the released heat from the adsorption bed be transferred to the desorption bed. This simulation is performed for the bulk separation of air (21% oxygen ; 79% nitrogen) in Skarstrom cycle and 5A zeolite is utilized as adsorbent. The second part of simulation is to separate water from air(air with relative humidity 90% , equivalent to a water concentration of 3.4241%). In the second part, the adsorbent used is γ-Alumina. This study uses the equilibrium model and the pressure drop can be neglected. We assumed instantaneous equilibrium between solid and gas phase with non-isothermal operation. The simulation results of flat-box type adsorbers and traditional cylindrical adsorbers are compared. The oxygen concentration of products of the flat-box adsorbers is higher than that of the traditional cylindrical adsorbers. From the graphs of adsorber’s temperature, expected temperature changes is observed. The effects of operating variables such as steps time, adsorption pressure, the ratio of bed width to bed height, the heat transfer coefficient between neighboring adsorbers are investigated on the performance of PSA.