Degradation of ethylene in fruit and vegetable cold storage using positive direct current corona discharge

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.