| 摘要: | 隨著國際社會推動2050年淨零排放目標，再生能源的比例將會大幅增加，為了解決再生能源的間歇性問題並提高電力調度的彈性，電轉氣（Power to Gas, P2G)技術已成為國際間積極推動的儲能技術。此技術能將多餘的再生能源經由電解水來產生氫氣，這些氫氣能被儲存也能藉由甲烷化將氫氣和二氧化碳進行反應，為了使氫氣不被浪費，甲烷化反應中常會以二氧化碳過量的方式來進行，經反應後，產物組成為二氧化碳、甲烷及乙烷。因此本研究目的為設計出一四塔十六步驟程序分離出高純度、高回收率甲烷以供後續能源使用並同時回收二氧化碳達到溫室
氣體減量目標。
本研究使用模擬探討以變壓吸附法(pressure swing adsorption, PSA)進行CO2甲烷化反應後之氣體高純度純化分離，依據文獻資料根據選擇率擇定沸石13X做為吸附劑。隨後，本研究以程序模擬結合實驗設計(design of experiment, DOE)，找出以進料條件為67.9%甲烷、30%二氧化碳及2.1%乙烷時之四塔十六步驟PSA
程序之分離最適化操作條件。
比較之前實驗室模擬三塔九步驟最佳化程序及本次四塔十六步驟PSA最佳化程序分離結果發現，甲烷的純度從95.91%上升至97.51%，甲烷回收率從97.93%上升至98.96%，二氧化碳的純度大約持平為90%，回收率則從90.47%大幅提升
至 94.41%，捕獲二氧化碳所花費的能耗則也從0.45 GJ/t-CO2下降至0.35 GJ/t-
CO2。
;With the global pursuit of net-zero emissions by 2050, the proportion of renewable energy is expected to significantly increase. To address the intermittency issues of renewable energy and enhance grid flexibility, Power to Gas (P2G) technology has emerged as a promising energy storage solution. This technology enables the conversion of surplus renewable energy into hydrogen through electrolysis, which can be stored and further utilized through methanation, a process that involves the reaction of hydrogen with carbon dioxide. To minimize hydrogen wastage, methanation reactions often employ excess carbon dioxide. The resulting products of the reaction are carbon dioxide, methane, and ethane. Therefore, the aim of this study is to design a four-bed sixteen-step pressure swing adsorption (PSA) process for the purification and separation of high-purity methane for subsequent energy utilization, while simultaneously recovering carbon dioxide to achieve greenhouse gas reduction targets.
In this study, a simulation program was used to perform high-purity gas purification and separation of CO2 methanation products using PSA. Based on literature data and selectivity considerations, zeolite 13X was chosen as the adsorbent. Subsequently, the study combined process simulation with design of experiment (DOE) to identify the optimal operating conditions for a four-bed sixteen-step PSA process with feed composition of 67.9% methane, 30% carbon dioxide, and 2.1% ethane.
Comparing the results of the previous laboratory simulation of the three-bed nine-step PSA optimized process with the four-bed sixteen-step PSA optimized process, it was found that the methane purity increased from 95.91% to 97.51%, and the methane recovery increased from 97.93% to 98.96%. The purity of carbon dioxide remained approximately the same at around 90%, while the recovery significantly improved from 90.47% to 94.41%. The energy consumption required for capturing carbon dioxide also decreased from 0.45 GJ/t-CO2 to 0.35 GJ/t-CO2. |
