Thermal desorption dynamics test method of VOC of single pollution source in soil

Abstract

According to the invention, a mass loss rate curve of a soil sample is obtained by monitoring and recording the mass m of the soil sample in real time, the thermal desorption dynamics parameters of aVOC are obtained by analysis, and the problems that a VOC evaporative thermal desorption process in the soil deviates significantly from the intrinsic properties of a VOC pure substance, the prior artlacks an effective experiment to study the means of a desorption process of the VOC in the soil affected by multiple factors in a real condition and the thermal desorption dynamics research of VOC inthe soil cannot follow an existing desorption theory are solved. By using the method of the invention, the dynamics process of two stages of the thermal desorption of the VOC in the soil can be clearly studied and distinguished, relevant parameters can be obtained by fitting, and useful parameters and guidance are provided for a VOC-contaminated soil treated by a thermal desorption method.

Description

technical field [0001] The invention relates to an organic pollutant test method, in particular to a single pollution source VOC thermal desorption kinetic test method in soil. Background technique [0002] VOCs (volatile organic compounds) refer to organic compounds with a saturated vapor pressure greater than 133.32Pa at normal temperature and a boiling point below 50-260°C at normal pressure, or any organic solid or liquid that can volatilize at normal temperature and pressure. VOCs is a general term for a class of compounds with very complex compositions, including hundreds of compounds such as alkanes, alkenes, halogenated hydrocarbons, aromatic hydrocarbons, and aldehydes and ketones. VOCs in soil cover some of the above-mentioned organic substances, including halogenated hydrocarbons, aromatic hydrocarbons, etc. These VOCs generally have the characteristics of environmental accumulation, bioaccumulation, and high toxicity. [0003] With the development of petroleum ...

AI Technical Summary

Problems solved by technology

[0011] 3. The evaporation rate of VOCs in the soil is lower than that of pure VOCs (for example, the evaporation rate of pyrene is 5 times smaller than that of pure pyrene under the same conditions);

[0012] 4. The intercrystalline water layer in the soil has a significant inhibitory effect on the desorption of pollutants, and the mass transfer within and between particles significantly affects the removal rate of pollutants;

[0015] 7. Soil moisture content will directly affect the treatment operation cost. High clay content or humidity will increase the treatment cost. Therefore, there are strict requirements on the moisture content of polluted soil. Generally, the moisture content should not exceed 20%.

[0016] However, there are few relevant studies on the specific kinetic process of the two stages of thermal desorption of VOCs in soil, and the lack of relevant test methods and devices. learn little

[0017] Since the evaporation rate of VOCs in soil is much lower than that of pure VOCs, the melting point and boiling point of VOCs in soil are also much different from those of pure VOCs. Significantly affects the desorption process of VOCs, so that the evaporation thermal desorption process of VOCs in soil obviously deviates from the intrinsic properties of VOCs pure substances. to test

[0018] Moreover, since in the polluted soil, the surface of the soil particles and the interior of the soil particles are saturated with liquid or solid VOCs, the intercrystalline water layer in the soil, the size of the soil particles, the porosity, and the gas injection velocity all significantly affect the The desorption process of VOCs is extremely complicated, which makes it impossible to follow the existing desorption theory in the study of thermal desorption kinetics of VOCs in soil.