在酒精和水混合物的分離技術當中,於一大氣壓下,酒精和水組成為95.6wt%時,在78.2℃會瓹生共沸點,而吸附分離相較於傳統共沸蒸餾或萃取蒸餾為一種較節能的程序,因此被廣泛運用在酒精脫水。由於其吸附選擇性及再生效率較差,近年來有些學者開始利用澱粉等材料來當作吸附材,但未經處理的澱粉吸附材有膨潤及糊化等問題。因此,本研究利用Sol-Gel法成功將澱粉固定化在矽膠基材上,以解決澱粉在吸附上所遇到的問題。本論文先利用BET比表面積測定儀,使用固定化澱粉作為吸附劑,得到不同的吸附帄衡數據,由數學分析等溫線吸附帄衡關係式,取得等溫吸附帄衡曲線圖及其參數。最後由實驗方式將顆粒狀固定化澱粉填充於單一吸附塔中進行模擬,研究中藉由改變不同的操作條件(如進料濃度、氣體流速、吸附材顆粒大小及床層高度)探討各種變因對貫流行為的影響,並以傅立業紅外線光譜儀取代傳統氣相層析儀,快速有效率的偵測濃度的變化。結果可發現,貫流曲線的突破時間因進料濃度和氣體流速的增加而提前,而床層高度的增加會使突破時間延後。吸附材顆粒大小及床層高度對於出口濃度C/Co值影響較為顯著,且系統Roll-over 的現象也隨著氣體流速的增加而愈明顯。在動態吸附實驗中,其貫流曲線斜率及出口濃度 C/Co 值最能代表系統行為,本研就藉由回應曲面法( Response surface methodology, RSM ),發現在進料濃度為92%、吸附材顆粒為1~2 mm、進料氣體流速為500 sccm及床層高度7 cm 速率下,為本研究實驗範圍內的佳操作條件。
In the distillation separation of ethanol vapor and water vapor, it can form an zoetrope at 78.2℃, at which there are 95.6wt% ethanol and 4.4wt% water. Traditional azeotropic distillation and extractive distillation to obtain anhydrous ethanol need more energy than adsorption. Adsorption as a low energy consumption process has attracted attention to apply in ethanol dehydration. Recently, some investigators have tried to use starch to replace Zeolite 3A. However, it has a low efficiency in adsorption selectivity and regeneration and starch powder was become glue after adsorption with water vapor. In the present study, starch was immobilized using sol-gel method to solve these problems. This study obtained adsorption equilibrium data by the BET experiment for water and ethanol on immobilized starch. Then isotherm curve and the parameters by numerical method and expressed by the Langmuir isotherm. The isotherm is applied to analyze the effect of the variables such as feed concentration, velocity, particle size and bed length on the breakthrough performance. Breakthrough curves of ethanol were measured by using a gas-phase FT-IR instead of traditional GC. Application of the gas-phase FT-IR could detect changes of gas concentration more fast than the traditional GC. Results showed that on influence of feed concentration, velocity, particle size and bed length is significant on different on breakthrough time and breakthrough curve shape. The effects of particle size and bed length on outlet concentration (C/Co) is significant, with increase of the velocity the roll-over phenomenon is more obvious. In dynamic absorption, the slope of breakthrough curve and C/Co may represent mass transfer behavior. The optimum experimental parameters were expressed as follows: Inlet concentration: 92%, particle size: 1~2 mm, velocity: 500 sccm and the length of the bed: 7cm.
為了持續優化網站功能與使用者體驗,本網站將Cookies分析技術用於網站營運、分析和個人化服務之目的。
若您繼續瀏覽本網站,即表示您同意本網站使用Cookies。