| 摘要: | 現今的科學家認為造成全球暖化是排放過多二氧化碳，因此碳捕獲與存放的技術是很重要的，真空變壓吸附法是一種捕獲煙道氣中二氧化碳的方法之一，此方法是使用吸附劑在混合氣體中不同氣體有不同的吸附選擇性來分離氣體且是連續循環程序的技術，本研究以捕獲燃煤電廠煙道氣中二氧化碳，使用EKIME zeolite 13X為吸附劑，目標為達到塔底產物二氧化碳純度90%以上，回收率90%以上。
首先利用突破曲線實驗和單塔三步驟真空變壓吸附程序實驗捕獲燃煤電廠煙道氣與模擬結果進行驗證，確認模擬程式的可靠性。接著以第一階段二塔六步驟和第二階段單塔三步驟為二階段真空變壓吸附程序模擬分離以經除硫、除水後組成含11% 二氧化碳與89%氮氣的煙道氣，達到塔底產物二氧化碳純度90.33% 和回收率78.82%。
最後以第一階段二塔六步驟進行實驗設計(Design of Experiments, DOE)找出最佳操作條件為當進料壓力4 atm、真空壓力0.05 atm、同向減壓壓力1 atm、塔長80 cm、步驟1/4時間302 s、步驟3/6時間60 s、進料二氧化碳濃度13.76%的操作條件下，可達到塔底二氧化碳純度62.17%、回收率94.75%、能耗1.26 GJ/t-CO2，再經第二階段變壓吸附程序後，最終達到塔底二氧化碳純度90.33%、回收率90.26%，總能耗1.55 GJ/ t-CO2。
;The scientists believe the excessive carbon dioxide cause the global warming now. Therefore, the technology of carbon capture and storage is very important. Pressure swing adsorption (PSA) process is one of the methods to capture carbon dioxide in flue gas. This method uses adsorbents to separate gases with different adsorption selectivities in the mixed gas and is a continuous cycle process. This study aims to capture carbon dioxide in the flue gas of coal-fired power plants, and uses zeolite 13X as the adsorbent to achieve a bottom carbon dioxide product with purity 90% and recovery 90%.
To verify the reliability of simulation program, the results of the breakthrough curve experiment and the 1-bed 3-step PSA process experiment, which is used to capture the flue gas of coal-fired power plant, were compared with the simulation results. Both the experiment and simulation results are consistent, which shows that the simulation program is reliable. Next, the first stage 2-bed 6-step PSA and the second stage 1-bed 3-step PSA are used as the two-stage PSA process to simulate the separation of flue gas (11% CO2, 89% N2) after desulphurization and water removal in coal-fired power plant. The simulation results show a bottom product CO2 purity at 90.33% with 78.82% recovery.
Finally, this study combined the simulation of 2-bed 6-step PSA process with design of experiments (DOE) method to find the optimal operating conditions of the first stage PSA. After simulation analysis, the bottom product CO2 purity 62.17% with 94.75% recovery from the first stage PSA was obtained while at feed pressure 4 atm, vacuum pressure 0.05 atm, cocurrent depressurization 1 atm, bed length 80 cm, step 1/4 time 302 s, step 3/6 time 60 s, feed CO2 concentration 13.76% as the optimal results. After the second stage PSA process, we obtained a bottom product CO2 purity at 90.33% with 90.26% total recovery. The total mechanical energy consumption was estimated to be 1.55 GJ/t-CO2. |
