Research On On-line Measuring Instrument For Ethanol Concentration In Fermentation Based On Gas Sensing Effect

In the Animalcule fermentation process, ethanol concentration is one of the most important variables, and directly influences the optimization and automatic control performance of fermentation system as well as the quality and yield of the output. The existing methods for ethanol concentration measurements are almost off-line which result in the delay. The on-line measurements based on optical principle and acoustic principle only measure the ethanol concentration of a binary solution of ethanol-water. The method based on biological principle is not yet ripe and will result in contamination of yeast tun. So further studying the on-line measure of ethanol concentration in the fermenting condition is indispensable.Based on the detailed analysis of the current methods of ethanol concentration measure, method of ethanol on-line measure based on vapor-liquid equilibria law and gas sensing effect principle is studied. Based on this method, the design of hardware and software of measuring instrument for ethanol concentration are provided.The results of experiments show that the method of the on-line measurement and the measure model based on vapor-liquid equilibria law and gas sensing effect principle can measure ethanol concentration on-line, and the measuring instrument for ethanol concentration can measure on-line with±2% precision. This meets the demand of the measure of ethanol concentration, and adapts to the ethanol measure in fermenting condition.