Research on the effect of atmospheric pressure fluctuation on the migration and transformation of benzene in soil based on TMVOC simulation
-
摘要:
为探究大气压力波动下苯系物（BTEX）的迁移转化规律，提升石化污染场地土壤地下水污染治理水平，以西北某炼化场地为研究对象，结合室内土柱试验与TMVOC软件模拟，开展BTEX泄漏模拟，研究不同大气压力波动幅度下苯在包气带与含水层中的迁移转化规律。结果表明：大气压力循环波动会引起包气带中的气相苯发生相间非平衡态迁移，导致气相质量分数增加0.1%~0.5%；非水相液体（NAPL）污染物转化为气相污染物，进而通过大气挥发是主要的质量损失方式，该转化会造成场地及周边的大气环境污染；同时大气压力波动的幅度与气相转变发生时间存在负线性相关关系。研究显示，大气压力波动显著影响了苯的相态转化与迁移过程，促进了苯的相态转化，使得更多的苯转化为气相，造成大气环境污染。
-
关键词:
- 挥发性有机化合物(VOCs) /
- 包气带 /
- 大气压力波动 /
- TMVOC
Abstract:In order to explore the migration and transformation law of benzene series (BTEX) under the fluctuation of atmospheric pressure, and improve the control level of soil and groundwater pollution in petrochemical-polluted sites, a refinery site in northwest China was taken as the research object and, combined with indoor soil column experiment and TMVOC software simulation, BTEX leakage simulation was carried out to explore the migration and transformation law of benzene in the vadose zone and aquifer under different amplitude of atmospheric pressure fluctuation. The results show that the atmospheric pressure cycle fluctuation can cause the gaseous benzene in the vadose zone to migrate to the non-equilibrium state, resulting in the increase of the gaseous mass fraction by 0.1%-0.5%. The conversion of non-aqueous liquid (NAPL) phase pollutants into vapor phase pollutants and their volatilization through the atmosphere is the main way of leakage quality loss, and this transformation will cause atmospheric pollution in the site and its surroundings. At the same time, the amplitude of atmospheric pressure fluctuation is negatively correlated with the time of gaseous transition. The study shows that the atmospheric pressure fluctuation significantly affects the phase transformation and migration process of benzene, promotes the phase transformation of benzene, and makes more benzene transform into gas, resulting in atmospheric environmental pollution.
-
Key words:
- volatile organic compounds(VOCs) /
- vadose zone /
- atmospheric pressure fluctuation /
- TMVOC
-
图 3 TMVOC所考虑的相组成与相变
注：g为气相；w为液相（溶解相）；n为NAPL相；gw为液相-气相；wn为液相-NAPL相；gn为NAPL相-气相。
Figure 3. Phase compositions and phase changes considered by TMVOC
图 4 在不同迁移时间及采样深度下A、B土壤柱中苯浓度的分布情况
Figure 4. Distribution of concentration benzene in soil columns A and B at different migration times and depth
图 5 不同深度下A、B土壤柱在24和48 h后的苯浓度分布情况
Figure 5. Distribution of benzene concentration in soil columns A and B at different depths after 24 h and 48 h
图 6 模拟大气压力波动下BTEX的NAPL相质量分数变化
Figure 6. NAPL phase mass fraction of BTEX under simulated atmospheric pressure fluctuations
图 7 模拟大气压力波动下BTEX气相质量分数变化
Figure 7. Gaseous mass fraction of BTEX under simulated atmospheric pressure fluctuations
图 8 模拟大气压力波动下BTEX液相质量分数变化
Figure 8. Aqueous mass fraction of BTEX under simulated atmospheric pressure fluctuation
图 9 气压波动下不同深度土壤中苯的不同相态质量分数变化
Figure 9. Mass fraction of benzene in different phases in soil at different depths under different atmospheric pressures
图 10 不同大气压力下−40和−50 cm处的苯各相态质量分数变化
Figure 10. Mass fraction of benzene in different phases at −40 and −50 cm under different atmospheric pressures
图 11 不同表层气压下−10 cm处气相苯的质量分数变化
Figure 11. Mass fraction of benzene in gas phase at −10 cm under different surface pressures
表 1 苯的理化性质
Table 1. Physical and chemical properties of benzene
摩尔质量/（g/mol） 标准沸点/K 临界温度/K 临界压力/kPa 临界体积/（cm3/mol） 密度/（kg/m3） 偏心因子 偶极矩 分配系数（Koc）/（m3/kg） 78.114 353.2 562.2 4.82×106 259.0 885.0 0.212 0.0 0.089 1 
下载: 导出CSV
表 2 试验设计与取样时间
Table 2. Experimental design and sampling schedule
土壤柱 0~3 d气压波动设置 A柱 1）加压1 000 Pa，并维持8 h；
2）恢复气压至标准大气压，静置18 hB柱 初始状态与A柱保持一致，不加压，
之后的采样时间同样与A柱保持一致
下载: 导出CSV
表 3 概化模型参数
Table 3. Generalized model parameters
渗透系数/（cm/s） pH 土壤容重/（kg/m3） 含水率/% 孔隙度 5.6×10−4 6.2 1 650 21 0.15
下载: 导出CSV
表 4 苯的扩散系数
Table 4. Diffusion coefficient of benzene
气相中扩散
系数/（m2/s）液相中扩散
系数/（m2/s）NAPL相扩散
系数/（m2/s）水中溶解度/
（mol/mol）7.7×10−6 6.0×10−10 6.0×10−10 4.11×10−2
下载: 导出CSV
-
[1] 周艳, 姜登登, 孔令雅, 等. 典型农药污染场地地下水中苯系物监控自然衰减研究[J]. 环境科学学报,2022,42(7):380-388.ZHOU Y, JIANG D D, KONG L Y, et al. Research on monitored natural attenuation of BTEX in groundwater of a typical pesticide-contaminated site[J]. Acta Scientiae Circumstantiae,2022,42(7):380-388. [2] 谭海涛, 刘涛, 曹兴涛, 等. 石化场地土壤与地下水污染防控研究进展[J]. 应用化工,2020,49(8):2112-2115. doi: 10.3969/j.issn.1671-3206.2020.08.052TAN H T, LIU T, CAO X T, et al. Research progress of soil and groundwater environment conservation for petrochemical site[J]. Applied Chemical Industry,2020,49(8):2112-2115. doi: 10.3969/j.issn.1671-3206.2020.08.052 [3] 刘海萍, 鲁炳闻, 杨刚, 等. P&T-GC∕MSD测定地表水比对样品中苯系物不确定度的评定[J]. 环境工程技术学报,2017,7(5):600-605.LIU H P, LU B W, YANG G, et al. Evaluation of uncertainty of benzene series in surface water by P & T-GC∕MSD in interlaboratory comparison[J]. Journal of Environmental Engineering Technology,2017,7(5):600-605. [4] 董炎青, 陈英, 陈勇, 等. 土壤甲苯泄漏扩散及影响因素的三维数值模拟[J]. 油气田地面工程,2018,37(7):14-18. doi: 10.3969/j.issn.1006-6896.2018.07.005DONG Y Q, CHEN Y, CHEN Y, et al. Three-dimensional numerical simulation of toluene leakage and influencing factors in soil[J]. Oil-Gasfield Surface Engineering,2018,37(7):14-18. doi: 10.3969/j.issn.1006-6896.2018.07.005 [5] DAKHEEL ALMALIKI A J, BASHIR M J K, LLAMAS BORRAJO J F. Appraisal of groundwater contamination from surface spills of fluids associated with hydraulic fracturing operations[J]. Science of the Total Environment,2022,815:152949. doi: 10.1016/j.scitotenv.2022.152949 [6] CHEN X L, SHENG Y Z, WANG G C, et al. Microbial compositional and functional traits of BTEX and salinity co-contaminated shallow groundwater by produced water[J]. Water Research,2022,215:118277. doi: 10.1016/j.watres.2022.118277 [7] 郑菲, 高燕维, 施小清, 等. 地下水流速及介质非均质性对重非水相流体运移的影响[J]. 水利学报,2015,46(8):925-933.ZHENG F, GAO Y W, SHI X Q, et al. Influence of groundwater flow velocity and geological heterogeneity on DNAPL migration in saturated porous media[J]. Journal of Hydraulic Engineering,2015,46(8):925-933. [8] 张晓惠, 王冬梅, 焦永杰, 等. 我国苯的环境暴露、风险评估与管控[J]. 生态毒理学报,2020,15(3):202-209. doi: 10.7524/AJE.1673-5897.20191111001ZHANG X H, WANG D M, JIAO Y J, et al. Environmental exposure, risk assessment and control of benzene in China[J]. Asian Journal of Ecotoxicology,2020,15(3):202-209. doi: 10.7524/AJE.1673-5897.20191111001 [9] EL-HASHEMY M A, ALI H M. Characterization of BTEX group of VOCs and inhalation risks in indoor microenvironments at small enterprises[J]. Science of the Total Environment,2018,645:974-983. doi: 10.1016/j.scitotenv.2018.07.157 [10] BOLDEN A L, KWIATKOWSKI C F, COLBORN T. New look at BTEX: are ambient levels a problem[J]. Environmental Science & Technology,2015,49(9):5261-5276. [11] 李凌波, 林大泉, 曾向东, 等. 某石油化工厂区有机污染物的表征I. 土壤[J]. 石油学报(石油加工),2001,17(4):87-96.LI L B, LIN D Q, ZENG X D, et al. Characterization of organic contamination at a petrochemical site i. soil[J]. Acta Petroles Sinica,2001,17(4):87-96. [12] XU C Y, LIN X M, YIN S S, et al. Spatio-vertical characterization of the BTEXS group of VOCs in Chinese agricultural soils[J]. Science of the Total Environment,2019,694:133631. doi: 10.1016/j.scitotenv.2019.133631 [13] 葛锋, 张转霞, 扶恒, 等. 我国有机污染场地现状分析及展望[J]. 土壤,2021,53(6):1132-1141.GE F, ZHANG Z X, FU H, et al. Distribution of organic contaminated sites in China: statu quo and prospect[J]. Soils,2021,53(6):1132-1141. [14] 孙兴凯, 黄海, 王海东, 等. 大型污染场地修复过程中的问题探讨与工程实践[J]. 环境工程技术学报,2020,10(5):883-890. doi: 10.12153/j.issn.1674-991X.20190216SUN X K, HUANG H, WANG H D, et al. Discussion of problems in the process of large-scale contaminate sites remediation and project practice[J]. Journal of Environmental Engineering Technology,2020,10(5):883-890. doi: 10.12153/j.issn.1674-991X.20190216 [15] US EPA. Superfund remedy report[EB/OL]. [2023-09-20]. https://www.epa.gov/remedytech/superfund-remedy-report. [16] 马妍, 董彬彬, 徐东耀, 等. VOCs∕SVOCs污染土壤常用修复技术及其在美国超级基金污染场地中的应用[J]. 环境工程技术学报,2016,6(4):391-396. doi: 10.3969/j.issn.1674-991X.2016.04.058MA Y, DONG B B, XU D Y, et al. Common used remediation technologies for volatile and semivolatile organic compounds contaminated soils and their application in US superfund sites[J]. Journal of Environmental Engineering Technology,2016,6(4):391-396. doi: 10.3969/j.issn.1674-991X.2016.04.058 [17] 王颖, 陈雷, 杨洋, 等. 基于TMVOC的地下水位波动带苯系物迁移转化模拟[J]. 环境科学研究,2020,33(3):634-642.WANG Y, CHEN L, YANG Y, et al. Numerical simulation of BTEX migration in groundwater table fluctuation zone based on TMVOC[J]. Research of Environmental Sciences,2020,33(3):634-642. [18] 杨洋, 赵传军, 李娟, 等. 低温条件下基于TMVOC的土壤气相抽提技术数值模拟[J]. 环境科学研究,2017,30(10):1587-1596.YANG Y, ZHAO C J, LI J, et al. Numerical simulation through SVE technique based on TMVOC under low temperature[J]. Research of Environmental Sciences,2017,30(10):1587-1596. [19] CHEN C, GREEN R E, THOMAS D M, et al. Modeling 1, 3-dichloropropene fumigant volatilization with vapor-phase advection in the soil profile[J]. Environmental Science & Technology,1996,30(1):359. [20] TILLMAN F D Jr, CHOI J W, SMITH J A. A comparison of direct measurement and model simulation of total flux of volatile organic compounds from the subsurface to the atmosphere under natural field conditions[J]. Water Resources Research,2003,39(10):1284. [21] TILLMAN F D Jr, SMITH J A. Site characteristics controlling airflow in the shallow unsaturated zone in response to atmospheric pressure changes[J]. Environmental Engineering Science,2005,22(1):25-37. doi: 10.1089/ees.2005.22.25 [22] MASSMANN J, FARRIER D F. Effects of atmospheric pressures on gas transport in the vadose zone[J]. Water Resources Research,1992,28(3):777-791. doi: 10.1029/91WR02766 [23] YANG Y S, LI P P, ZHANG X, et al. Lab-based investigation of enhanced BTEX attenuation driven by groundwater table fluctuation[J]. Chemosphere,2017,169:678-684. doi: 10.1016/j.chemosphere.2016.11.128 [24] CAVELAN A, GOLFIER F, COLOMBANO S, et al. A critical review of the influence of groundwater level fluctuations and temperature on LNAPL contaminations in the context of climate change[J]. Science of the Total Environment,2022,806:150412. doi: 10.1016/j.scitotenv.2021.150412 [25] KACEM M, BENADDA B. Mathematical model for multiphase extraction simulation[J]. Journal of Environmental Engineering,2018,144(6):04018040. doi: 10.1061/(ASCE)EE.1943-7870.0001378 [26] LU N. Time-series analysis for determining vertical air permeability in unsaturated zones[J]. Journal of Geotechnical and Geoenvironmental Engineering,1999,125(1):69-71. doi: 10.1061/(ASCE)1090-0241(1999)125:1(69) [27] PRUESS K, PRUESS K. TOUGH2: a general-purpose numerical simulator for multiphase fluid and heat flow[R]. Berkeley: Lawrence Berkeley National Lab, 1991. [28] 王颖, 汪洋, 唐军, 等. 基于TMVOC的水位波动带土壤气相抽提模拟[J]. 中国环境科学,2020,40(1):350-356. doi: 10.3969/j.issn.1000-6923.2020.01.039WANG Y, WANG Y, TANG J, et al. Numerical simulation of SVE in groundwater table fluctuation zone based on TMVOC[J]. China Environmental Science,2020,40(1):350-356. doi: 10.3969/j.issn.1000-6923.2020.01.039 [29] PRUESS K, BATTISTELLI A. TMVOC, a numerical simulator for three-phase non-isothermal flows of multicomponent hydrocarbon mixtures in saturated-unsaturated heterogeneous media [M]. Berkeley: Lawrence Berkeley National Laboratory, 2002. [30] MA Y, DONG B B, HE X S, et al. Quicklime-induced changes of soil properties: implications for enhanced remediation of volatile chlorinated hydrocarbon contaminated soils via mechanical soil aeration[J]. Chemosphere,2017,173:435-443. doi: 10.1016/j.chemosphere.2017.01.067 [31] 时延锋. 典型有机污染物在饱和多孔介质中的运移研究[D]. 南京: 南京大学, 2019. [32] 马妍, 李发生, 徐竹, 等. 生石灰强化机械通风法修复三氯乙烯污染土壤[J]. 环境污染与防治,2014,36(9):1-6. doi: 10.3969/j.issn.1001-3865.2014.09.001MA Y, LI F S, XU Z, et al. Quicklime-enhanced remediation of trichloroethylene contaminated soils by mechanical soil aeration[J]. Environmental Pollution and Control,2014,36(9):1-6. doi: 10.3969/j.issn.1001-3865.2014.09.001 [33] SHAN C, STEPHENS D B. An analytical solution for vertical transport of volatile chemicals in the vadose zone[J]. Journal of Contaminant Hydrology,1995,18(4):259-277. doi: 10.1016/0169-7722(95)00011-J [34] 戚圣琦, 侯德义, 王轶冬, 等. VOCs相间非平衡态迁移对土壤修复效果的影响[J]. 环境科学研究,2021,34(6):1464-1472.QI S Q, HOU D Y, WANG Y D, et al. The influence of VOCs nonequilibrium transport on soil remediation[J]. Research of Environmental Sciences,2021,34(6):1464-1472. [35] QI S Q, LUO J, O'CONNOR D, et al. Influence of groundwater table fluctuation on the non-equilibrium transport of volatile organic contaminants in the vadose zone[J]. Journal of Hydrology,2020,580:124353. ⊗ doi: 10.1016/j.jhydrol.2019.124353 -
下载:
点击查看大图
计量
- 文章访问数: 95
- HTML全文浏览量: 93
- PDF下载量: 35
- 被引次数: 0
