标题: 以冷媒R134a萃取乙醇
Extraction of ethanol using Refrigerant R134a
作者: 叶志强
余艇
应用化学系硕博士班
关键字: 冷煤;乙醇;萃取;R134a;Ethanol;extraction
公开日期: 2003
摘要: 蒸馏浓缩乙醇是个非常昂贵的操作方法,因为乙醇和水会有共沸的现象,因此会增加纯化上的成本及困难度,加上近几年来,有许多学者研究利用超临界二氧化碳(SF-CO2)来萃取水溶液中的乙醇,所以,本实验尝试以液态1,1,1,2-tetrafluoroethane (R134a)取代SF-CO2来萃取浓缩乙醇,操作压力比SF-CO2降低约100个大气压以上,实验中并尝试加入甘油(glycerol)、乙二醇(ethylene glycol)、丙二醇(1,3-propanediol)、丙二醇(propylene glycol)等修饰剂于萃取中来提升萃取率,但其实验结果证明加入此四种修饰剂于R134a中,并不能增加乙醇萃取的回收率,同时,我们也测量乙醇于R134a中不同温度下的溶解度。另外,在60 oC下且分别在20 bar和50 bar时,当乙醇水溶液的初浓度超过84 wt%,可以将乙醇水溶液浓缩至共沸组成浓度(95.57 wt%)以上。
Production of absolute ethanol using distillation is a high energy-consuming process. Due to the formation of the azeotrope, it complicates the final purification to make absolute ethanol. In recent years, researchers have investigated in using supercritical fluid carbon dioxide (SF-CO2) to extract ethanol from aqueous solutions. In this study, we attempted using 1,1,1,2-tetrafluoroethane (R134a) in substituting SF-CO2 as the extraction solvent due to the much lower operational pressures of R134a. Experiments were carried out under various pressures and temperatures to optimize the process. The extraction recoveries of ethanol were found higher than those of using SF-CO2, based on the same extraction volumes. However, the enrichment of ethanol has not been as good as in using SF-CO2 due to the higher solubility of water in R134a. Even so, concentration of ethanol exceeding the azeotropic composition, i.e., 95.57 wt%, could still be achieved while the initial sample concentration was above 84%. In addition, four organic compounds (glycerol, ethylene glycol, 1,3-propanediol and propylene glycol) were added to the sample solutions in order to increase the recovery rates. The outcome showed that the extraction recoveries decreased with the addition of these compounds.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009125550
http://hdl.handle.net/11536/55068
显示于类别:Thesis


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  1. 555001.pdf
  2. 555002.pdf
  3. 555003.pdf
  4. 555004.pdf
  5. 555005.pdf
  6. 555006.pdf
  7. 555007.pdf
  8. 555008.pdf
  9. 555009.pdf
  10. 555010.pdf
  11. 555011.pdf
  12. 555012.pdf

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