CO_2入侵包气带对土壤热参数的影响  

Effect of High Concentration of CO_2 Permeation into the Unsaturated Zone on Soil Thermal Parameters

作　　者：张青海[1] 邓红章[1] 赵晓红[1] 韩枫[1] 李春荣[1] 裴宇[1] 张徽[2] 

机构地区：[1]长安大学旱区地下水文与生态效应教育部重点实验室,陕西西安710054 [2]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《当代化工》2016年第4期668-672,676,共6页Contemporary Chemical Industry

基　　金：国家自然科学基金项目;1)二氧化碳入侵包气带的温度效应与模拟(41302207)。2)超常压二氧化碳入侵粘土层的水岩作用及水文地质意义(41302208)。3)二氧化碳入侵包气带对地表植物的影响和环境指示(41302286)。<二氧化碳地质储存环境影响与监测技术方法研究>(12120113006400)

摘　　要：CO_2地质储存是一种缓减碳排放行之有效的途径,但是逃逸的CO_2入侵包气带将带来土壤热性质的变化。土壤包气带热参数直接控制着大气环境和土壤的热量交换,进而影响土壤的生态环境。为了研究土壤包气带热参数对高浓度CO_2的响应规律,采用人工模拟CO_2在包气带中泄漏的方法,通过检测CO_2在土壤中的扩散规律并通过测试土壤含水率、干容重及热参数来研究CO_2对土壤热性质的影响。结果表明:在实验设定的CO_2浓度范围内,从低区到高区随CO_2浓度升高,包气带热导率平均值由0.9 W/mK减小到0.5 W/mK,体积热容量由1.5减小到1.2 MJ·m^(-3)·K^(-1);低浓度区土壤包气带体积热容量对CO_2的敏感性高于热导率;不同CO_2浓度影响了体积热容量与含水率的线性关系,低浓度区具有最好的线性关系,线性回归相关系数R2为0.741 9。在设定的CO_2浓度梯度内CO_2对土壤包气带热参数的影响有特定的规律,为研究CO_2对土壤包气带热量传递奠定了基础。Carbon dioxide geological storage is an effective way to mitigate carbon emission; but once the leaking CO_2 invades into the soil＇s unsaturated zone, the soil thermal properties will change. The thermal parameters in the unsaturated zone directly control the heat exchange of atmosphere and soil, therefore, the change of which can affect the ecological environment of soil. In order to study the effect of high concentration of CO_2 permeation into the soil＇s unsaturated layer on the thermal parameters, the experiment applied artificial simulation process of CO_2 leakage into unsaturated zone to detect the transportation rule. By testing the soil moisture, dry bulk density and thermal parameters, the impact of CO_2 on the soil thermal properties was studied. The results show that,within the range of experimental settings, with increase of CO_2 concentration from low density regions to high density regions, the average thermal conductivity value of the vadose zone reduces from 0.9 W / mK to 0.5 W / mK, the volumetric heat capacity reduces from 1.5 to 1.2 MJ·m（-3）·K（-1）. The soil vadose zone＇s volumetric heat capacity in the low density regions is more sensitive than the thermal conductivity. And different CO_2 concentrations might affect the linear relationship between volumetric heat capacity and moisture content, the low CO_2 test areas have the best linear relationship with the linear regression correlation coefficient R2 =0.7419. In the range of CO_2 concentration gradient settings, the effect of CO_2 permeation into the unsaturated zone on soil thermal parameters has specific rules, these results can be used for further research on the unsaturated zone＇s heat transfer.

关 键 词：CO2 土壤包气带 体积热容量 热导率 

分 类 号：X131.3[环境科学与工程—环境科学]