绝缘油污染土壤微波脱附试验

采用微波-热重反应装置,针对绝缘油污染土壤进行微波热脱附试验,考察不同温度下绝缘油脱附效率以及污染土壤失重规律,并在此基础上对土壤中残余绝缘油组分及分布进行分析。结果表明:当温度达到400℃以上时,土壤中绝缘油去除效果较好,绝缘油去除率可达到98.6%,能够满足土壤修复要求。含油土壤随着温度升高主要经历水分挥发、易挥发性有机物析出、难挥发性有机物析出等阶段,在100~200℃阶段,主要是土壤中水分和部分低挥发性有机物析出;在400~500℃阶段,主要是土壤中绝缘油析出。土壤中绝缘油的成分以C12—C21烷烃类化合物和5~6环芳香烃为主,当温度达到400℃以后,绝缘油中各组分逐步被完全脱附,综合考虑脱附效率和经济性原则,绝缘油污染土壤脱附温度以400~450℃为宜。

EXPERIMENTAL STUDY ON MICROWAVE DESORPTION OF SOIL CONTAMINATED BY INSULATING OIL

Microwave-thermogravimetric reaction device was used to conduct microwave thermal desorption test for insulating oil contaminated soil. The desorption efficiency of insulating oil and the weightlessness rule of contaminated soil were investigated at different temperatures. Based on this, the composition and distribution of residual insulating oil in soil were analyzed. The results showed that when the temperature was above 400 ℃, the removal efficiency of insulating oil in soil was better, and the removal rate of insulating oil could reach 98.6%, which met the requirements of soil remediation. With the increase of temperature, the oil-bearing soil mainly experienced the stages of moisture volatilization, volatile organic compounds and volatile organic compounds. At the stage of 100~200 ℃, moisture and some low volatile organic compounds in the soil were mainly precipitated. At the stage of 400~500 ℃, the insulating oil in the soil was mainly precipitated. The main components of insulating oil in soil were C12—C21 alkanes and 5~6 cyclic aromatic hydrocarbons. When the temperature reached 400 ℃, each component of insulating oil was gradually desorbed completely. Considering the principles of desorption efficiency and economy, the appropriate desorption temperature for insulating oil contaminated soil was between 400 ℃ and 450 ℃.