有机污染黏壤土热脱附后热导率的变化特性  

Changes in thermal conductivity of organic contaminated clay loam after thermal desorption

作　　者：吴宇豪 尹立普 王晴[3] 范利武[1,4] 俞自涛[1,4] WU Yuhao;YIN Lipu;WANG Qing;FAN Liwu;YU Zitao(Institute of Thermal Science and Power Systems,School of Energy Engineering,Zhejiang University,Hangzhou 310027,China;China State Science Dingshi Environmental Engineering Corporation Limited,Beijing 100101,China;Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学能源工程学院热工与动力系统研究所,杭州310027 [2]中科鼎实环境工程有限公司,北京100101 [3]中国科学院南京土壤研究所,南京210008 [4]浙江大学能源清洁利用国家重点实验室,杭州310027

出　　处：《环境工程学报》2021年第12期3967-3973,共7页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划(2019YFC1805701)。

摘　　要：为探究有机污染土壤热脱附后热导率的变化特性,采集了苏州市某原位热脱附修复场地编号为G01、G06和G09的示范区域深度为0~3 m的土壤(系黏壤土),并利用实验室的小型热脱附装置在350℃的条件下对污染土壤试样进行了1 h热脱附;对其热脱附前后的粒径分布以及热脱附后的化学组成(矿物质和有机质的质量分数)进行了表征,并用探针式导热仪测试了其热导率。结果表明,在高温热脱附处理过程中,土壤颗粒的团聚作用比破碎作用更强,导致热脱附后土壤粒径增大;当密度、含水率和温度等条件保持一致时,热脱附后土壤的热导率较场地原位测试时无显著变化,平均值在1.4~1.5 W·(m·℃)^(−1);随温度升高或干密度增大,土壤热导率均增大,且干密度对热导率的影响比温度更加显著。此外,3个采样区域的土壤热导率呈现一定的差异,其中,G06区域的热导率最大而G01区域最小,最多相差0.055 W·(m·℃)^(−1),这主要是由不同区域土壤中矿物质(其热导率是有机质的3倍以上)质量分数的变化所致。本研究结果可为实际热修复场地的地层温升预测提供参考。In order to explore the changes in thermal conductivity of organic contaminated soil after thermal desorption,soils(clay loam)with a depth of 0~3 m at the demonstration areas numbered G01,G06 and G09 in an in-situ thermal desorption remediation site in Suzhou City were collected,and then were deal with thermal desorption at 350℃for 1 h by the lab-scale thermal desorption apparatus.Particle size distributions before and after thermal desorption and chemical compositions(mass percentage of minerals and organic matters)after thermal desorption of the soil samples were characterized,and the thermal conductivity was measured by a probe-type thermal conductivity meter.The results showed that the increase of soil particle size after thermal desorption was due to the fact that the agglomeration effect of soil particles was stronger than the fragmentation effect during the high-temperature treatment.When density,moisture content and temperature were kept constant,the thermal conductivity of the soil samples after thermal desorption had no significant changes compared with the in-situ measured results,with the average results being 1.4~1.5 W·(m·℃)^(−1) Soil thermal conductivity increased with either increasing the temperature or increasing the dry density,and the effect of dry density was more pronounced.In addition,there was a variation of the thermal conductivity of soil samples among the three areas,where G06 area was the highest and G01 area was the lowest with the maximum discrepancy being 0.055 W·(m·℃)^(−1).Such variation was mainly due to the changes in mass percentage of minerals,which had a thermal conductivity that was over 3 times greater than that of organic matters.These results could provide a reference for predicting the temperature rise in practical thermal remediation sites.

关 键 词：有机污染 黏壤土 热脱附 热导率 

分 类 号：TK124[动力工程及工程热物理—工程热物理] X53[动力工程及工程热物理—热能工程]