高频交流电晕等离子体降解农用地膜的特性研究

Characterization of High Frequency AC Corona Plasma for Degradation of Agricultural Land Film

地膜的使用为农业发展带来了极大的便利,但大量的残膜同时也造成了极为严重的白色污染,而目前针对残膜的降解处理研究又极为缺乏。低温等离子体降解技术作为一种高效、绿色的污染物处理方法,可以通过在反应空间生成大量高能电子和活性物质对污染物进行降解。首先采用高频交流针板电晕放电结构,针对电极结构进行优化设计,提高反应空间内的电场强度的电子密度。然后通过电晕等离子体降解技术对地膜进行处理,最后对比了不同的放电功率、空气湿度、针膜间距、放电间距对地膜降解的影响效果。结果表明:针尖的形状和针针之间的距离会对电子密度和电场强度造成不同程度的影响,当针尖斜率为3.33,针针间距为12 mm时,电子密度和电场强度最大,分别为1.55×10^(13) m^(-3)和1.2×10^(6) V/m;放电功率的增大会导致空间内能量密度的提高,从而提高空间内高能电子和活性物质的产生效率,提高地膜的降解效率,当输入功率为64 W时降解效率最高达到0.96%,但能量效率会随着输入功率的升高先增大后减小,当输入功率为56 W达到最佳能量效率为34.29μg/(W·h);空气湿度的增加不仅会导致放电形态发生变化出现稳定的微放电,也会提升活性物质的产生效率,当空气湿度达到70%RH时,地膜降解效率提升1.04倍;地膜与针尖之间的距离也会导致稳定的微放电产生,将降解效率由0.43%提升至1.02%;此外,针板电极的间距也会对降解效率产生影响,当放电间距为15 mm时可以达到最佳的等离子体的辐射范围和辐射强度,使降解效率和能量效率均达到最大,与仿真条件一致,分别为2.3%和68.18μg/(W·h)。

The use of mulch has brought great convenience to agricultural development,but at the same time,it can cause extremely serious white pollution,and there is a lack of relevant degradation treatment research.Low-temperature plasma degradation is a highly efficient and green treatment technology that degrades pollutants by generating high-energy electrons and active substances in the reaction space.Firstly,a high frequency alternating current needle plate corona discharge structure was used to optimize the design for the electrode structure.Then,the plastic film was treated by corona plasma degradation technology,and finally the effects of different discharge power,air humidity,needle film spacing and discharge spacing on the degradation of plastic film were compared.Then,the plastic film was treated by corona plasma degradation technology,and finally the effects of different discharge power,air humidity,needle film spacing and discharge spacing on the degradation of plastic film were compared.The results show that the shape and distance of the needle tip will affect the electron density and electric field intensity to different degrees,and when the slope of the needle tip is 3.33 and the spacing between the needles is 12 mm,the electron density and electric field intensity are the largest,which are 1.55×10^(13) m^(-3) and 1.2×10^(6) V/m,respectively.The increase of the discharge power will lead to the increase of the energy density in the space,thus increasing the energetic particles in the space When the input power is 64 W,the degradation efficiency is up to 0.96%,but the energy efficiency will increase first and then decrease with the increase of input power.When the input power is 56 W,the optimal energy efficiency is 34.29μg/(W·h).The increase of the air humidity not only leads to the change of the discharge form and the appearance of stable micro-discharge,but also affects the content of the active material,leading to the degradation of the film.The distance between the ground film and the tip of the needle will also lead to stable micro-discharge,which will increase the degradation efficiency from 0.43%to 1.02%.In addition,the distance between the electrodes of the needle plate will also have an impact on the degradation efficiency,when the distance between the discharge is 15 mm can meet both the radiation range and radiation intensity of the plasma,the degradation efficiency and energy efficiency will reach the maximum,which are 2.3%and 68.18μg/(W·h),respectively.