全球暖化問題日益嚴重，其中二氧化碳及其他溫室氣體乃是造成全球暖化之主因。如何減緩二氧化碳之排放，已成為世界各國在降低溫室氣體影響方面的研究重點。減緩二氧化碳氣體排放主要包含回收與抑制等方式。回收方式是指將排放至大氣的二氧化碳利用物理、化學或是生物方式回收，常見的有吸收法、變壓吸附法、薄膜分離法、低溫蒸餾法等，而其中變壓吸附法在節能上佔有較大之優勢，亦無二次污染之問題，故已被廣泛的應用在氣體分離上。而二氧化碳之排放最主要的來源為發電及工業界中利用天然氣或碳氫化合物產氫的製程上，目前經由氣化爐氣化煤炭後捕獲二氧化碳之技術，乃是先經由水煤氣轉化反應（water-gas shift reaction），再經過冷卻器降溫以將水汽去除後再加以捕獲二氧化碳，之後再將氫氣等產物升溫以接續之後的發電程序，但此一先降溫後升溫的步驟增加了許多能源上的浪費。 本研究將利用數值模擬的方法，模擬於中高溫下，在含有水汽、一氧化碳、二氧化碳及氫氣等成份中，利用多塔之變壓吸附製程與吸附劑的搭配，分離出二氧化碳及氫氣，並且探討各操作變數(如：進料壓力、吸附塔塔長、步驟時間等)對模擬結果的影響，尋求最佳的分離操作條件，以達到兼顧能源與環保的雙重目標。 Global warming has become more and more serious, which is caused by greenhouse gases. Cutting down the emission of CO2 has already become the major research target in the world. Several ways including physical, chemical and biological methods are possible to capture CO2 before it emits to atmosphere, such as chemical absorption, pressure swing adsorption (PSA), membrane separation, refrigeration/cryogenic etc. PSA performs better in saving energy and wouldn’t cause the second pollution, so it has been used widely on gas separation. The main sources of CO2 include the processes of generating electric power and producing hydrogen from natural gas and hydrocarbon. The CO2 which comes from coal is generated by gasifier and the water-gas shift reaction step of the process. The syngas after gasifier and water-gas shift reaction is cooled downed to remove water and to capture CO2 first in current technology, before the rest gas is heated again for power generation. The steps of cooling and heating cause the waste of energy. This study plans to use multi-bed PSA process to separate high purity hydrogen and to capture CO2 from syngas, which contains water vapor, CO, CO2 and hydrogen, at medium/high temperature. The optimal operating condition is discussed by varying the operating variables, such as feed pressure, length of adsorber and step time. By PSA process, the goal of energy generation and environmental protection could be achieved at the same time.
