- 學位論文
發酵液中吸附分離純化正丁醇研究
Adsorption Separation and Purification of n-Butanol from the Fermentation Broth
摘要
隨著全球暖化及能源危機的趨勢，生質能源的開發與應用成為現今的研究目標。近年，生質丁醇為新興的替代能源，它有高的熱值、低揮發性、低吸濕性，而且不只可以混溶到汽油中，也可以混溶於柴油中，生質丁醇為發酵液中之產物，然而，發酵液丁醇之濃度至多到30g/L(3wt%)，其低濃度造成工業上傳統分離純化十分耗能，而吸附為一個有潛力及節能的技術，在過去有不同吸附劑被拿來討論吸附丁醇，高矽鋁比沸石ZSM-5(Zeolite Socony Mobil-5)型分子篩對吸附丁醇很好的效果，由於ZSM-5不只會吸附丁醇，也會吸附發酵液中副產物乙醇及丙酮，因此使用不同矽鋁比之ZSM-5型分子篩吸附模擬發酵液，本研究發現在競爭吸附下，丁醇有高的吸附量，其次為丙酮，再來為乙醇，此外，在不同矽鋁比之ZSM-5中，高矽鋁比之ZSM-5在低濃度有好的吸附量，隨著溫度的升高，丁醇吸附量會隨之下降，因而認為ZSM-5吸附丁醇應為物理吸附，使用Langmuir及Freundlich model迴歸結果，Langmuir model較適合用於ZSM-5液相吸附，而高矽鋁比ZSM-5不只適合用Langmuir model迴歸同時也適合用Freundlich model迴歸，因此認為在室溫條件下，高矽鋁比之ZSM-5為適合分離純化丁醇之吸附劑。
並列摘要
Due to the trend of global warming and the energy crisis, the biomass energy development and application have become important. In recent years, the bio-butanol is the emerging alternative energy that has a higher combustion value, lower volatility, lower hygroscopic than ethanol and not only miscible into gasoline but also diesel fuel. Bio-butanol is the product of the fermentation broth. However, the concentration of butanol in the fermentation broth is only up to 30g / L (3wt%). The low concentration results in the use of more energy for separation and purification in industry, and absorption is a potential energy saving technology. In the past research, butanol adsorption was discussed by many different adsorbents. High silica/alumina ratio zeolites, ZSM-5(Zeolite Socony Mobil-5) series, have good affinity for butanol. In this study, it was found that competitive adsorption was observed in the fermentation broth, and butanol has a high adsorption capacity, followed by acetone and ethanol. In addition, for the different silica/alumina ratio of ZSM-5 series, ZSM-5(SiO2/Al2O3=300) at low concentration has a good absorption capacity. For the increasing temperature, the adsorption amount of butanol decrease. Thus, ZSM-5 adsorption is considered to be the physical adsorption. For the result of Langmuir and Freundlich model regression, Langmuir model is more suitable for liquid phase adsorption. High silica/ alumina ratio ZSM-5 is the most suitable adsorbent for the separation and purification of butanol.