| 摘要: | 隨著工業革命伴隨著大量化石燃料燃燒，產生出的二氧化碳造成溫室效應增強進而造成氣候變遷，在近年來環保意識增加，如何減少二氧化碳的議題受到密切關注，其中一種方法是變壓吸附法(PSA)，透過氣體間不同的吸附性能達到分離混合氣的效果，是一種低投資成本及操作簡單的物理吸附法，本實驗透過此技術捕獲燃煤電廠排放之煙道氣中的二氧化碳。
首先利用高壓氣體分析儀及數位記錄天平量測COSMO 13X在不同溫度下對CO2的等溫吸附曲線，計算不同溫度及不同壓力下的平衡吸附量，確認本實驗選用的吸附劑對二氧化碳有著良好的分離效果。
接著使用兩階段真空變壓吸附程序，並選擇COSMO 13X作為塔內填充物，以分離台中燃煤電廠排放的煙道氣中的氮氣和二氧化碳。首先，透過第一階段實驗(兩塔六步驟)達到高二氧化碳回收率的目標，然後通過第二階段實驗(單塔三步驟)提高二氧化碳的純度。為了探討第一階段實驗結果的影響因素，結合實驗設計和分析，採用兩水準三因子全因子實驗設計。這三個因子分別是步驟1/4的時間、步驟3/6的時間和同向減壓壓力。透過研究這些因子對純度、回收率和能耗對實驗結果的影響，建立各個響應的迴歸模型，找到最佳化的操作條件。目標是在第一階段實驗中獲得80 %以上的二氧化碳回收率。
透過四種不同最適化探討後，比對之後得到當步驟1/4的時間為250秒、步驟3/6的時間為40秒和同向減壓壓力為0.85 bar時，可獲得一階段二氧化碳純度79.11 %及回收率87.08 %之最適化結果。;With the industrial revolution came the burning of large amounts of fossil fuels, resulting in the release of carbon dioxide and intensifying the greenhouse effect, leading to climate change. In recent years, there has been an increased awareness of environmental protection, and the issue of reducing carbon dioxide has received close attention. One method for achieving this is Pressure Swing Adsorption (PSA), which utilizes the different adsorption properties of gases to separate mixed gases. It is a physically-based adsorption method that requires low investment costs and simple operation. In this experiment, PSA method was used to capture carbon dioxide from the flue gas emitted by coal-fired power plants.
First, the high-pressure gas analyzer and digital recording balance were used to measure the isothermal adsorption curves of COSMO 13X for CO2 at different temperatures. The equilibrium adsorption capacity at different temperatures and pressures was calculated to confirm that the chosen adsorbent in this experiment exhibits good separation efficiency for carbon dioxide.
Next, a two-stage vacuum pressure swing adsorption (VPSA) process was employed, with COSMO 13X chosen as the tower packing material, to separate N2 and CO2 in the flue gas emitted by the Taichung coal-fired power plant. Firstly, the first stage experiment (two-bed six-step PSA) was conducted to achieve a high carbon dioxide recovery rate. Then, through the second stage experiment (single-bed three-step PSA), the purity of carbon dioxide was increased. To investigate the influential factors in the results of the first stage experiment, a combination of experimental design and analysis was employed, using a two-level three-factor full factorial experimental design. These three factors are the time for steps 1/4, the time for steps 3/6, and the co-current depressurization pressure. By studying the effects of these factors on purity, recovery rate, and energy consumption in the experimental results, regression models were established for each response to determine the optimal operating conditions. The objective is to achieve an 80% or higher carbon dioxide recovery rate in the first stage experiment.
After comparing four different optimizations, it was determined that when the time for step 1/4 is 250 seconds, the time for step 3/6 is 40 seconds, and the Co-current depressurization pressure is 0.85 bar, the optimal result yields a carbon dioxide purity 79.11 % with recovery 87.08% in the first-stage. |
