| 摘要: | 隨著科技發展，大氣中溫室氣體濃度逐年增加，因此越來越多比例的太陽輻射無法逸散出去，造成全球平均溫度年年升高，異常的年均溫會造成極地融冰，氣候變遷以及傳染病的增加，因此，如何減少溫室氣體的排放儼然成為全球各國該共同探討的議題。
本研究為氣化合成氣經富氧燃燒後之雙塔變壓吸附程序二氧化碳純化實驗。合成氣經由與氧氣燃燒及除水後，會產出濃度95%以上的二氧化碳氣體，因此本實驗進料氣體組成採用95%二氧化碳與5%氮氣。吸附劑選擇方面，藉由比較不同吸附劑對二氧化碳與氮氣的吸附量及選擇率，選用UOP 13X 沸石作為吸附劑。將吸附劑填入吸附塔進行突破曲線與脫附曲線實驗，藉由改變不同溫度與壓力探討不同變因對突破曲線與脫附曲線的影響，以此為基礎粗估步驟所需時間，進而以雙塔六步驟變壓吸附程序來純化二氧化碳，並探討如操作溫度、進料壓力、逆向減壓壓力、沖洗量對進料量之比值、步驟時間等變因對其各個出口回收率、濃度的影響，併計算產率和能耗，研究最適化的操作條件，以獲得高純度二氧化碳。變因探討後之最佳操作條件為進料壓力3.45 atm、逆向減壓壓力0.48 atm、塔溫度358K、進料加壓/逆向減壓步驟時間150秒、高壓吸附/低壓沖洗步驟時間20秒、同向減壓/Idle步驟時間250秒，沖洗量對進料量之比值0.105。最佳塔底二氧化碳純度為99.94%，回收率42.84%，能耗0.304 GJ/tonne CO2，產率0.136 kg CO2/kg adsorbent．h。
;With the industry development, the concentration of greenhouse gas increases year by year, and thus more and more solar radiation is restrained in the atmosphere, resulting in the increase of average global temperature gradually. The abnormal average global temperature will cause melting ice in polar region, climate change and the increased spreading speed of infectious diseases. Consequently, how to reduce the emission of greenhouse gas has become an important issue all over the world.
This research is the experimental study of concentrating high purity CO2 from syngas after oxy-fuel combustion by dual-bed pressure swing adsorption process. Syngas after oxy-fuel combustion and dehydration will produce CO2 with purity more than 95%, and therefore the composition of feed gas used in the process was assumed 95% CO2, with 5% N2 balanced. We chose UOP 13X zeolite as the best adsorbent that will be used in the dual-bed PSA process according to the adsorption capacity and selectivity of CO2 over N2 comparing to other zeolites.
The breakthrough and desorption curves were discussed by changing different feed flow rate and temperature. Next the carbon dioxide was purified by dual-bed six-step pressure swing adsorption process. After exploring the effects of variables such as temperature, feed pressure, vacuum pressure, purge to feed ration, and step time on performance of pressure swing adsorption process, we found the best operating conditions for obtaining high purity carbon dioxide among our experiments. The best operating conditions are feed pressure 3.45 atm, countercurrent depressurization pressure 0.48 atm, temperature 358 K, feed pressurization / countercurrent depressurization step time 150 s, adsorption / purge step time 20 s, cocurrent depressurization / idle step time 250 s, purge to feed ratio 0.105. The experimental results of best conditions are 99.94% purity and 42.84% recovery of carbon dioxide at bottom product, energy consumption 0.304 GJ/tonne CO2 and productivity 0.136 kg CO2/kg adsorbent．h。 |
