煤炭先經過粉煤機磨成粉狀後送入氣化爐內，與空氣在高溫高壓下混合燃燒而產生粗煤氣，再經過除塵、除硫後成為乾淨的合成氣，其主要成分為一氧化碳、二氧化碳、甲烷與氫氣。藉由變壓吸附法可以產出高濃度的氫氣做為能源使用，以應用於新興能源的供應上；而將二氧化碳回收封存則可減少其對溫室效應造成的影響，達到兼顧能源與環保的雙重目標。 變壓吸附法為一分離氣體混合物之連續性循環程序，利用氣體混合物中各成分對吸附劑之吸附能力的不同而產生的吸附選擇性來篩選氣體，並利用高壓吸附、低壓脫附以得到高濃度的產物。 本研究將利用數值模擬的方法，發展出一套有效的變壓吸附系統以分離合成氣，達到濃縮產生高濃度氫氣與回收一氧化碳、二氧化碳的目標。模擬上將分成三個階段，利用多塔之變壓吸附製程與吸附劑的搭配，處理組成為55%一氧化碳、33%氫氣、12%二氧化碳的合成氣體；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，以做為未來建立大規模工廠設備之參考。 Coal is sented into the gasifier and burned with air at high temperature and pressure to generate the raw gas. After passing through gas clean-up system the raw gas becomes the syngas with main components such as carbon monoxide, carbon dioxide, methane and hydrogen. Pressure swing adsorption can purify hydrogen with high concentration to be used as energy source and recover carbon dioxide to decrease the impact on the greenhouse effect. For energy source and environment protection, it is important to separate these two components and to handle them separately. Pressure swing adsorption is a cyclic process to separate gas mixtures based on the difference of adsorption capacity of each component on adsorbent. This technology consists of gas adsorption at high pressure and desorption at low pressure to produce high-purity product. This study plans to develop an effective PSA system for achieving the goals of hydrogen purification and recovery of carbon monoxide and carbon dioxide from syngas by using numerical simulation. The PSA process includes three stages. Syngas with 55% carbon monoxide, 33% hydrogen and 12% carbon dioxide to be separated by multi-bed PSA process and several adsorbents are studied. And the optimal operating condition is discussed by varying the operating variables, such as feed pressure, length of adsorber and step time. The simulation results suggest PSA information for the after-IGCC factory design in the future.
