火力發電廠所排放出含硫量過高之氣體是造成酸雨現象的主要原因，另外排放大量的二氧化碳是造成全球溫室效應的主要原因。使用變壓吸附法濃縮及回收煙道氣中二氧化硫、二氧化氮及二氧化碳，使之再利用，為解決問題方法之一。近來這方面的研究已成為處理這類工廠廢氣之首要。 本研究主要利用模擬方式，採用兩階段三塔六步驟真空變壓吸附程序，處理進料為0.5﹪SO2、0.13﹪NO2、18﹪CO2，其餘為N2之煙道氣，第一階段SO2-VSA (vacuum swing adsorption) 程序吸附劑採用Doewx MWA-1處理二氧化硫與二氧化氮，第二階段CO2-VSA程序吸附劑採用13X沸石處理二氧化碳。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。 此一新程序可將濃度為0.5﹪SO2濃縮至6.31%，回收率達90%；0.13﹪NO2濃縮至0.96%，回收率達52%；18﹪CO2濃縮至73%，回收率達86%；本研究並探討各操作參數(諸如：各個步驟操作時間、進料壓力、脫附壓力與沖洗比等)對程序效能的影響。 The major cause for acid-rain phenomena is the emission of SO2 from power plants that burn fossil flues, and the major cause for greenhouse effect is the emission of CO2 from power plants. It is important to recover and concentrate SO2, NO2 and CO2 from flue gas in solving those problems. Pressure swing adsorption is a feasible process in treating such problems. This study uses a two-stage vacuum swing adsorption process, with each stage composed of a three-bed six-step operation. Simulation is performed for the bulk separation of SO2/NO2/CO2/N2 (0.5/0.13/18/81.37 vol %) system. The first stage of SO2-VSA (vacuum swing adsorption) utilizes Dowex MWA-1 as adsorbent, and the second stage of CO2-VSA utilizes 13X zeolite as adsorbent. This study uses the equilibrium model and the pressure drop can be neglected. We assumed instantaneous equilibrium between the solid and gas phase with non-isothermal operation. The 0.5%SO2 in the feed can be concentrated to 6.31% in the product with a recovery of 90%, the 0.13%NO2 in the feed can be concentrated to 0.96% in the product with a recovery of 52%, and the 18%CO2 in the feed can be concentrated to 73% in the product with a recovery of 86%. The effects of operating variables such as P/F ratio, adsorption pressure, desorption pressure, and steps time are investigated on the performance of this study.
