酒精发酵过程中导电性变化机制的解析及基于此酒精发酵过程的在线检测

Online monitoring technics of indexes in fermentation and online determination methods of ferment end point were both always the hot researching topics/fields in international fermentation process control. he mechanism on the changes of electric conductivity and the online monitoring of alcoholic fermentation process based on electric conductivity would be firstly studied in this project, then the practicabilities of using electrical conductivity process for online monitoring and end point determination of alcoholic fermentation would be further investigated, and there were no other reports on such research at home and abroad. In our early research, results showed that there were certain logical relationships between the conductivity change to reducing sugar and alcohol content respectively. If the mathematical model among the above three indexes could be simulated by BP neural network, then the changes of reducing sugar and alcohol content would be inspected at any moment during fermentation process, and the end point of alcoholic fermentation would be online determined. In order to make better use of the established BP neural network model in practice, factors affecting the changes of electric conductivity during alcoholic fermentation would be mainly studied and the established electric conductivity detection method would be used in the online monitoring of pilot scale alcoholic fermentation process. The results of this research would have important theoretical significance both for increasing the economic benefits and reducing the environmental pollution of enterprises.

发酵过程指标的在线监测和发酵终点的在线判定一直都是国际上研究的热点问题。本课题是对酒精发酵过程中导电性的变化机制和基于电导率酒精发酵过程的在线监测进行研究，进而探讨利用电导率在线监测酒精发酵过程和判定酒精发酵终点的实用性，有关这一方面的研究尚未见报道。经本课题组前期研究发现，在酒精发酵过程中电导率与还原糖以及酒精度之间存在着一定的线性关系，通过BP神经网络建立三者之间良好的数学模型，既可以监测发酵过程中酒精度和还原糖的变化是否异常，又可以判断酒精发酵的终点。为了使构建的数学模型更好地应用于实践，本课题重点研究酒精发酵过程中引起导电性变化的各种影响因素以及各因素的差异显著性，并应用于酒精发酵过程在线监测的中试生产。该研究成果对于提高企业的经济效益和降低企业对环境的污染均具有重要的现实意义。

酒精发酵过程指标的在线监测和发酵终点的在线判定一直是该领域研究的重要问题之一。本课题组在前期研究中确立了酒精发酵过程中导电性和酒精浓度之间的相互关系，进而继续探讨酒精发酵过程中电导率的变化机理以及利用电导率在线监测酒精发酵过程和判定酒精发酵终点的实用性。. 基于上述目的,本实验研究了酒精发酵过程中电导率与乙醇浓度、还原糖浓度、发酵液总离子浓度、酵母细胞浓度之间的相互关系曲线，研究了发酵过程关键因素对发酵过程中电导率变化的影响，确立了乙醇浓度是酒精间歇发酵过程中电导率变化的决定性因素。根据这一提法，我们利用电导率的变化来在线监测酒精发酵过程和在线判断酒精发酵过程的终点。通过收集大量试验数据，利用BP神经网络建立电导率与酒精浓度和还原糖浓度三者之间的数学模型，使构建的数学模型更好地应用于实践。利用构建的数学模型获得的乙醇浓度的模拟值和实验室离线检测的试验值虽然还存在着0.364%的最大误差，这部分内容还有待于进一步具体研究。尽管如此，该实验成果应用于酒精间歇发酵过程的在线检测和发酵终点的判断，同样可以节省实验室每4 h 取样浪费的原料，显著降低实验室工作人员的劳动强度。以200 m3发酵罐为例，每发酵罐至少可以节省15 L发酵醪，发酵醪酒精质量浓度平均按13.5%计算，则年产10 万t 酒精厂每年可多生产1500 t酒精。这一结果在今天激烈的市场竞争和环境保护等方面，都具有非常重要的意义。. 该项目研究到目前为止，发表论文3篇，1篇EI，1篇EI收录，还有1篇SCI正处于审稿阶段，同时申请并获得国家授权专利1项。本课题重点研究酒精发酵过程中引起导电性变化的各种影响因素以及各因素的差异显著性，并应用于酒精发酵过程在线监测的中试生产。该研究成果对于提高企业的经济效益和降低企业对环境的污染均具有重要的现实意义。