基于原位热脱附技术修复污染土壤的加热井数值优化

NUMERICAL OPTIMIZATION OF HEATING WELLS FOR REMEDIATION OF CONTAMINATED SOIL BASED ON IN-SITU THERMAL DESORPTION TECHNOLOGY

原位热脱附技术(ISTD)作为一种物理修复土壤技术,具有污染土壤原位处置、二次污染少、工艺原理简单、高效灵活等优点。针对实际修复土壤过程中不合理的排布方式和对保温措施的忽略造成的脱除率低、能源浪费等问题,利用COMSOL Multiphysics软件模拟污染土壤1000 h的加热过程,在模型验证的基础上探讨了不同排布方式、不同加热井间距和保温措施对土壤升温过程的影响。结果表明:在处理200℃以上沸点的污染物时,选用1.5 m间距下的三角形排布方式能够达到最优的修复效果,并且耗能相对较低。土壤表面施加保温措施,不仅可以防止污染气体泄漏,还可以有效提高加热土壤过程的热效率,采用2.0 m间距下的三角形排布方式施加保温措施后,热效率可相对提高11.667%。

In situ thermal desorption(ISTD),as a kind of physical soil remediation technology,has the advantages of in situ disposal of contaminated soil,less secondary pollution,simpler process principle,and higher efficiency and flexibility.In view of the problems of low removal efficiency and energy waste caused by unreasonable arrangement and neglection of thermal insulation measures in the actual process of soil remediation,COMSOL Multiphysics software was used to simulate the 1000 h heating process of contaminated soil.Based on the model verification,the effects of different arrangement methods,spacing of heating wells and thermal insulation measures on soil heating process were discussed.The results showed that when treating pollutants with a boiling point above 200℃,the triangular arrangement of 1.5 m heating well spacing could meet the treatment temperature requirements faster,and the energy consumption was relatively lower.Applying thermal insulation measures on the soil surface could not only prevent the leakage of polluted gas,but also effectively improve the thermal efficiency of soil heating process.In the triangular arrangement,the thermal efficiency was relatively increased by 11.667%after thermal insulation measures applied with a distance of 2.0 m between heating wells.