Using the optical method to measure the concentration of methanol within the liquor of ethanol

• Main Authors: Chia-Hsing Shen, 沈佳興
• Other Authors: Ming-Jyi Jang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/5gxrz3

碩士 === 遠東科技大學 === 機械研究所 === 97 === In this study, we use a non-destructive method and high-precision measuring technique to detect the light transmittance and refractive index of solutions. By measuring the light transmittance and refractive index of methanol/ethanol solutions, we can obtain a quadratic curve. From this curve, we can determine the concentration of methanol in the ethanol solution. The measuring system is composed of laser interferometer, quartz tank, optical lenses and electric motor. We can find out the optical characteristics from different solutions by this measuring system and mathematical analysis. To use this measuring technique can understand the optical characteristics at different methanol/ethanol concentration and determine the concentration of methanol in the ethanol solution. To build the refractive index database at different methanol/ethanol concentration, we can calculate the methanol concentration in the ethanol solution. From the analysis results, we can effectively measuring the refractive index of methanol/ethanol solutions. At the same concentration, the refractive index of ethanol is bigger than the refractive index of methanol. When we add the methanol and ethanol up, we could find that the refractive index would become lower. When the solution was diluted with water, we could find a quadratic equation to describe the relationship between the refractive index and concentration. When the methanol and ethanol have the same equivalent concentration, we could understand the optical property is closed to methanol. In this paper, we develop a discriminative method for determining the concentration of methanol in the ethanol solution. In the feature, we could efficiently distinguish the unknown concentration of solution from the quadratic curve and measuring the concentration of methanol in the ethanol solution.