正直流电晕放电降解果蔬冷藏环境中乙烯

摘要

In order to probe the feasibility of an innovative method of ethylene degradation in fruit and vegetable storage using a positive direct current corona, taking a multi-needle-to-cylinder type corona discharge reactor as research object, the impact of key parameters, including the discharge power per unit volume, the air flow rate and the air relative humidity, on the discharge characteristics and the degradation efficiency of ethylene were studied in this article. The results showed that the positive direct current corona discharge had an excellent effect on degradation of ethylene and the Weibull model could be used to describe the discharge degradation of ethylene. The corona threhold voltage decreased with an increasing of either the air relative humidity or the air flow rate, and the operating range of voltage increased as the air relative humidity raising, yet the difference of the operating range of voltage was not obvious for the air flow rate. A quadratic model was established using a central composite rotation experimental design plan and a least squares regression to describe the relationship between the degradation rate in term of tR value(the time needed to degrade 90% of the ethylene in a concentration) of the Weibull model and the affecting parameters, and the effectiveness of this model was verified. Using this model the impact of the discharge power per unit volume, the air flow rate and the air relative humidity were discussed. This paper could provide a basis for the application of this method to degrade ethylene in fruit and vegetable cold storage and for the further studying on the plasma-driven photocatalyst hybird system.%为了了解正直流电晕放电技术作为一种新的降解园艺产品保鲜环境中乙烯方法的可行性.该文以多针对圆筒内壁式电晕放电反应器为对象,进行了单位体积放电功率、混合气体流量和混合气体相对湿度等因素对电晕放电特性及乙烯降解效果的影响研究.结果表明:正直流电晕放电对乙烯降解有明显的效果,乙烯降解率的半经验模型动力学模型可用Weibull方程来描述；电晕起始电压随混合气体相对湿度、流量的增加而降低,电晕运行电压范围随混合气体相对湿度的增加而增大,但混合气体流量对电晕运行电压范围的影响不大；采用二次旋转组合实验和回归拟合,建立了90％乙烯降解所需的时间(tR)与影响因素关系的二次多项数学模型,验证了模型的有效性,并探讨了单位体积放电功率、混合气体流量和混合气体相对湿度对正直流电晕放电对乙烯降解的影响.为正直流电晕放电技术应用及进一步的等离子体催化技术的研究提供依据.