變壓式吸附為一週期性的分離程序，利用壓力變化為主要的操作變數，以達到分離的目的，此種程序於空氣分離以生產氧氣或氮氣上有日益重要的地位。而氣體進行吸附時會放熱，導致吸附塔溫度升高不利吸附，氣體進行脫附時會吸熱，導致吸附塔溫度降低不利脫附。本研究中將傳統的圓柱型吸附塔改為相鄰的平板型吸附塔，使得吸附的塔所放出的熱能傳至脫附的塔，期望平板型吸附塔的設計能讓整體PSA的效能有所提升。 本研究是利用模擬方式，採用Skarstrom Cycle程序，處理進料組成為21%氧氣與79%氮氣的空氣，使用的吸附劑為沸石5A。第二部份採用Skarstrom Cycle程序模擬由空氣中去除水氣的製程，進料為相對濕度90%的空氣，水氣佔3.4241%，所使用的吸附劑為γ-Alumina。模擬時所用的氣體分離機構為平衡模式，假設吸附塔內的同一截面積上固、氣兩相瞬間達成平衡，且為非恆溫之變壓吸附模式，因吸附劑顆粒大，故可忽略吸附塔內壓力降。 在比較平板型吸附塔與圓柱型吸附塔的模擬結果後，可發現前者的產物氧氣濃度略高於後者。而從各塔的溫度變化圖中可清楚的得知各塔的溫度變化如我們所預期。本研究並探討各操作變數(諸如：各個步驟操作時間、進料壓力、平板塔的寬高比、平板塔兩塔間的熱傳係數等)對模擬結果的影響。 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.
