WANG Fan;XU Bing;CHEN Lunjian;LI Congqiang;XING Baolin;SU Faqiang;

• 1:Henan Key Laboratory of Coal Green Conversion
• 2:School of Chemistry and Chemical Engineering
• 3: Henan Polytechnic University
• 4:Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization

Abstract：

Underground coal gasification(UCG) is a coal utilization technique that combines coal extraction and conversion. However, the potential for groundwater pollution has emerged as a significant obstacle to its widespread acceptance and implementation. With the background of the UCG with shaft, phenol solution was used as the simulated UCG-contaminated water. Sand, a mixture of sand and organic bentonite, a mixture of sand and activated carbon were used respectively to construct the permeation reactive barrier(PRB). The finite element method and the Python scientific computing libraries, NumPy and SciPy were adopted to develop numerical inversion programs to study the breakthrough process of phenol in different PRB. The results show that:(1) When the PRB was filled with sand and organic bentonite, the diffusion coefficient D and seepage velocity q increased, while the dispersion λ and retardation R decreased as the mass ratio of sand and organic bentonite increased. Conversely, when the PRB was filled with sand and activated carbon, the diffusion coefficient D, seepage velocity q, and retardation R decreased, while the dispersion λ increased with an increase in the mass ratio of sand and activated carbon.(2) The mass ratio of the mixed materials controls their porosity and adsorption capability, which significantly impacts the blockage and purification of phenol. When the PRB is constructed from sand and organic bentonite, increasing the mass ratio leads to an increase in porosity and a shorter initial detection time for phenol. On the other hand, when the PRB is constructed from sand and activated carbon, increasing the mass ratio results in a decrease in porosity, and the initial detection time for phenol increases at first and then decreases.(3) The adsorption and purification effect of a PRB on phenol and its mechanism can be explained as follows: in the case of a PRB material made up of sand and organic bentonite, there exists a threshold mass ratio(2∶1 in this experiment). When the mass ratio is below this threshold, the PRB effectively purifies phenol. However, when the mass ratio exceeds the threshold, the purification effect significantly decreases. On the other hand, in the case of a PRB material made up of sand and activated carbon, the dominant factor influencing the purification process is the seepage speed of the solution when the mass ratio of sand and activated carbon is below 2∶1. Conversely, when the mass ratio exceeds 2∶1, the adsorption performance of activated carbon becomes the dominant factor.

Key Words： underground coal gasification;groundwater pollution;permeable reaction barrier;numerical inversion;finite element

Abstract:

Keywords:

Foundation: 国家自然科学基金-新疆联合基金资助项目(U1803114);; 河南省自然科学基金资助项目(232300421335);; 河南省科技攻关资助项目(212102311069);; 河南省博士后基金资助项目(HN2022021)

Authors: WANG Fan;XU Bing;CHEN Lunjian;LI Congqiang;XING Baolin;SU Faqiang;

DOI: 10.13226/j.issn.1006-6772.23101901

References：

• [1] 于海洋，许永彬，陈智明，等.双碳目标下煤炭深部流态化开采及前景 [J].洁净煤技术，2023,29(1):15-32.YU Haiyang,XU Yongbin,CHEN Zhiming,et al.Deep fluidized coal mining and its prospect under the target of carbon peak and carbon neutralization[J].Clean Coal Technology,2023,29(1):15-32.
• [2] 谌伦建，徐冰，叶云娜，等.煤炭地下气化过程中有机污染物的形成 [J].中国矿业大学学报，2016,45(1):150-156.CHEN Lunjian,XU Bing,YE Yunna,et al.Formation of organic contaminants during underground coal gasification[J].Journal of China University of Mining & Technology,2016,45(1):150-156.
• [3] 刘淑琴，戚川，纪雨彤，等.煤炭地下气化制氢技术路径 [J].洁净煤技术，2023,29(8):1-10.LIU Shuqin,QI Chuan,JI Yutong,et al.Research on hydrogen production pathway by underground coal gasification [J].Clean Coal Technology,2023,29(8):1-10.
• [4] BARNWAL R P,BHARTI S,MISRA S,et al.UCGNet:wireless sensor network-based active aquifer contamination monitoring and control system for underground coal gasification[J].International Journal of Communication Systems,2017,30(1):e2852.
• [5] STRUGA?A-WILCZEK A,KAPUSTA K.Migration of Co,Cd,Cu,Pb to the groundwater in the area of underground coal gasification experiment in a shallow coal seam in the experimental mine ■ in Poland[J].Fuel,2022,317:122831.
• [6] STRUGA?A-WILCZEK A,KAPUSTA K,PANKIEWICZ-SPERKA M.Pollutants release from the residues remaining after underground gasification (UCG) of ortho-and meta-lignites[J].Fuel,2022,327:125126.
• [7] MA Weiping,LIU Shuqin,LI Zhen,at al.Release and transformation mechanisms of hazardous trace elements in the ash and slag during underground coal gasification [J].Fuel,2020,281(1):118774.
• [8] KAPUSTA K,STA■,et al.Environmental aspects of a field-scale underground coal gasification trial in a shallow coal seam at the Experimental Mine Barbara in Poland [J].Fuel,2013,113:196-208.
• [9] 刘淑琴，董贵明，杨国勇，等.煤炭地下气化酚污染迁移数值模拟 [J].煤炭学报，2011,36(5):796-801.LIU Shuqin,DONG Guiming,YANG Guoyong,et al.Numerical simulation of phenol migration for underground coal gasification[J].Journal of China Coal Society,2011,36(5):796-801.
• [10] 朱菲菲，秦普丰，张娟，等.我国地下水环境优先控制有机污染物的筛选 [J].环境工程技术学报，2013,3(5):443-450.ZHU Feifei,QIN Pufeng,ZHANG Juan,et al.Screening of priority organic pollutants in groundwater of China [J].Journal of Environmental Engineering Technology,2013,3(5):443-450.
• [11] 黄文建，陈芳，么强，等.地下水污染现状及其修复技术研究进展 [J].水处理技术，2021,47(7):12-18.HUANG Wenjian,CHEN Fang,YAO Qiang,et al.Research progress on groundwater pollution and its remediation technology [J].Technology of Water Treatment,2021,47(7):12-18.
• [12] 陈彦美，张玉，李锐颖，等.非正规生活垃圾填埋场污染地下水修复的PRB反应介质试验研究 [J].安全与环境工程，2023,30(2):203-215.CHEN Yanmei,ZHANG Yu,LI Ruiying,et al.Application of PRB reaction medium for polluted groundwater remediation in informal domestic waste landfill [J].Safety and Environmental Engineering,2023,30(2):203-215.
• [13] 张希，冯悦峰，李正斌，等.可渗透反应墙技术修复重金属污染地下水的发展与展望 [J].离子交换与吸附，2022,38(3):269-283.ZHANG Xi,FENG Yuefeng,LI Zhengbin,et al.Development and prospect of permeable reactive barrier for remediation of heavymetal contaminated groundwater [J].Ion Exchange and Adsorption,2022,38(3):269-283.
• [14] 王泓泉.污染地下水可渗透反应墙(PRB)技术研究进展 [J].环境工程技术学报，2020,10(2):251-259.WANG Hongquan.Study on permeable reactive barrier technology for the remediation of polluted groundwater[J].Journal of Environmental Engineering Technology,2020,10(2):251-259.
• [15] 李亮，徐建.组合材料应用于可渗透反应墙技术的研究进展 [J].工业水处理，2023,43(2):53-60.LI Liang,XU Jian.Research progress of combined materials applied in permeable reaction barrier technology[J].Industrial Water Treatment,2023,43(2):53-60.
• [16] 杨茸茸，周军，吴雷，等.可渗透反应墙技术中反应介质的研究进展 [J].中国环境科学，2021,41(10):4579-4587.YANG Rongrong,ZHOU Jun,WU Lei,et al.Research progress of reaction mediums in permeable reaction barrier technology[J].China Environmental Science,2021,41(10):4579-4587.
• [17] 林达红，徐文炘，张静，等.不同介质材料组合可渗透反应墙渗透性能试验研究 [J].矿产与地质，2016,30(2):255-257,293.LIN Dahong,XU Wenxin,ZHANG Jing,et al.Permeability test of permeable reactive barrier of different medium and material combinations [J].Mineral Resources and Geology,2016,30(2):255-257,293.
• [18] 陈仲如，张澄博，李洪艺，等.可渗透反应墙的结构与设计研究 [J].安全与环境学报，2012,12(4):56-61.CHEN Zhongru,ZHANG Chengbo,LI Hongyi,et al.On the structure and design of permeable reactive barrier [J].Journal of Safety and Environment,2012,12(4):56-61.
• [19] 王凡，谌伦建，徐冰，等.煤炭地下气化污染地下水的迁移与渗透反应墙净化数值模拟研究 [J].煤炭学报，2023,48(4):1697-1706.WANG Fan,CHEN Lunjian,XU Bing,et al.Numerical simulation on the migration and permeable reaction barrier purification of groundwater contaminated by UCG[J].Journal of China Coal Society,2023,48(4):1697-1706.
• [20] 吕永高，蔡五田，杨骊，等.中试尺度下可渗透反应墙位置优化模拟：以铬污染地下水场地为例 [J].水文地质工程地质，2020,47(5):189-195.LYU Yonggao,CAI Wutian,YANG Li,et al.A numerical simulation study of the position optimization of a pilot-scale permeable reactive barrier:A case study of the hexavalent chromium contaminated site [J].Hydrogeology & Engineering Geology,2020,47(5):189-195.
• [21] 汪强，徐建平.可渗透反应墙墙体内流速及流态数值模拟 [J].安徽工程大学学报，2014,29(3):12-16.WANG Qiang,XU Jianping.The numerical simulation of flow velocity and flow pattern in the permeable reactive barrier[J].Journal of Anhui Polytechnic University,2014,29(3):12-16.
• [22] ZHENG C,BENNETT G D.Applied contaminant transport modeling[M].New York:Wiley-Interscience,2002.
• [23] 中国煤炭工业协会.GB/T 23561.4—2009 煤和岩石物理力学性质测定方法第4部分：煤和岩石孔隙率计算方法[S].2009-04-08.
• [24] XU M,ECKSTEIN Y.Statisticalanalysis of the relationships between dispersivity and other physical properties of porous media [J].Hydrogeology Journal,1997,5(4):4-20.
• [25] II H.Effective porosity and longitudinal dispersivity of sediment-ary rocks determined by laboratory and field tracer tests [J].Environmental Geology,1995,25(2):71-85.
• [26] 陈焕利.煤炭地下气化半焦的物化性质及其对地下水污染的净化 [D].焦作：河南理工大学，2017.