Plasma Technology For Repairing Soil Contaminated By Insulation Oil

With the increase of social electricity consumption,more and more substation equipment will inevitably undergo insulation oil leakage in the process of transformation or replacement.Naphthenic hydrocarbons and aromatic hydrocarbons from the insulation oil do harm to water and farmland environment and even to human beings,animals and plants.Scholars at home and abroad have done a lot of research on the remediation technology of organic contaminated soil,which indicate that the existing technology is difficult to meet the requirements of short time,high efficiency and green environmental protection at the same time.As a new environmental remediation technology,plasma technology has the advantages of high speed,high efficiency and cleanliness,which provides a new idea for the remediation of organic contaminated soil.In this paper,the soil contaminated by insulation oil was treated by plasma technology,the effects of soil parameters,electrical parameters and carrier gas parameters on the treatment effect were investigated,and the energy utilization efficiency under different electrical conditions was compared.The degradation products of insulating oil were qualitatively analyzed by segmented GC-MS detection,and the feasibility and technological conditions of plasma technology applied to the remediation of soil contaminated by insulating oil were explored.The factors affecting the removal rate of insulating oil in contaminated soil were investigated by microsecond pulse dielectric barrier discharge system.The removal rate of insulating oil in soil increases gradually with the increase of processing time;the increase of initial pollutant concentration and soil thickness is not conducive to the removal of insulating oil;the best water content suitable for the degradation of insulating oil is 15%;the increase of input frequency and voltage is beneficial to the removal of insulating oil,comprehensively considering energy efficiency and removal effect,1000 Hz and 170 V are selected as the best electrical conditions;the increase of carrier gas flow rate is not conducive to the degradation of insulating oil.Oxygen content affects the removal of insulating oil by affecting the formation of active substances.Plasma technology shows high energy utilization efficiency in the remediation of contaminated soil,and a good remediation effect has been achieved.The microsecond pulse corona discharge system was used to explore the effect of the system on the remediation of soil contaminated by insulating oil.The removal rate of insulating oil increases with the increase of treatment time and decreases with the increase of initial concentration.When the moisture content is 15%,the removal effect of insulating oil is the best.With the increase of input voltage and discharge frequency,the removal rate of insulating oil increases and the degradation rate constant also increases.Considering the discharge effect,removal rate and energy consumption comprehensively,2000 Hz and 140 V are selected as the best electrical conditions.The increase of carrier gas is conducive to the formation of active particles,while too high carrier gas flow rate is not conducive to the reaction between active substances and insulating oil,which reduces the degradation effect of insulating oil.The changes of aliphatic and aromatic hydrocarbons in soil insulation oil before and after treatment were qualitatively analyzed by piecewise GC-MS method.After plasma treatment,the content of aliphatic hydrocarbons in soil insulation oil decreases obviously,which may be that the high carbon chain is oxidized and decomposed into low carbon chain under the action of active material.Plasma technology has a certain effect on the degradation of aromatic hydrocarbons in insulating oil.during the reaction,the benzene ring is opened,which is easy to combine with oxygen-containing,nitrogen-containing active groups and silicon dioxide in soil to form esters or silanization products.