石油烃污染的土壤间接热脱附关键影响因素研究

Study on Key Influencing Factors of Indirect Thermal Desorption of Petroleum Hydrocarbon Contaminated Soil

为探究不同运行工况和土壤特性等因素对石油烃(Total petroleum hydrocarbons, TPHs)污染土壤间接热脱附行为的影响,基于小型管式炉热脱附装置,以重柴油污染土壤为主要研究对象,辅以大庆实地污染土壤的验证,研究了加热温度、加热时间、土壤粒径、初始含水率、初始污染物浓度5个参数对TPHs污染土壤热脱附过程的影响。结果表明:加热温度是影响热脱附效率的最重要因素;加热时间一定程度上可以弥补加热温度的不足,作用大小受加热温度的影响;不同粒径的土壤具有不同的比表面积和传热传质能力,故表现出不同的吸附能力和热脱附曲线趋势;土壤初始含水率对热脱附效率的影响主要体现在前期,初始含水率过高且加热温度较高时,水分迅速蒸发导致土壤结壳,会阻塞内部污染物的扩散迁移;污染物初始浓度会影响热脱附曲线的变化,但对最终热脱附效率无明显影响。

Based on the small tubular furnace thermal desorption device, in order to explore the effects of different operating conditions and soil characteristics on the indirect thermal desorption behavior of petroleum hydrocarbons(TPHs) contaminated soil, the heavy diesel oil contaminated soil and Daqing field contaminated soil were collected for research. The effects of heating temperature,heating time, soil particle size, initial moisture content and initial pollutant concentration on the thermal desorption process of TPHs contaminated soil were studied. The results show that the heating temperature is the most important factor affecting the thermal desorption efficiency. Heating time can make up for the deficiency of heating temperature to a certain extent, and the effect is decided by heating temperature. Soils with different particle sizes have different specific surface area and heat and mass transfer capacity, so they show different adsorption capacity and thermal desorption curve trend. The influence of initial soil moisture content is mainly reflected in the early stage. When the initial moisture content is too high and the heating temperature is high, the rapid evaporation of water will lead to soil crust, which will block the diffusion and migration of internal pollutants. The initial concentration of pollutants will affect the change of thermal desorption curve,but it has no significant effect on the final thermal desorption efficiency.