摘要
煤炭地下气化符合我国能源低碳绿色转型发展方向,但地下水污染已成为限制其推广应用的技术瓶颈之一。渗透反应墙修复技术是地下水原位修复的研究热点之一。结合有井式地下气化的特点,利用数值模拟手段研究了渗透反应墙体厚度以及净化材料等对地下水中有机污染物迁移扩散和净化修复效果的影响。在对流扩散方程的基础上,假设:(1)地下水中污染物的吸附净化所涉及的质量转移与液相和固相吸附污染物质量浓度的差势、固相当前吸附质量浓度与潜在最大吸附质量浓度的差势和过程时间等因素有关。(2)活性炭较强的吸附性能可能导致固相吸附质量浓度逐渐累积而不再随外界液相质量浓度变化而解吸,采用有限元法和θ-格式迭代建立数值模型,利用MATLAB编写相应数值计算程序,对污染物迁移扩散以及吸附净化过程进行数值模拟与实验验证。结果表明:污染水的修复效果随渗透反应墙墙体厚度增加而增强,但增强幅度随着厚度的增加而减弱,墙体厚度的增加对污染物净化效果的影响呈边际效应递减趋势;墙体材料吸附净化速率越大,渗透反应墙对污染物的净化效果越好,渗透反应墙的吸附净化速率对污染物的净化效果也呈边际效应递减趋势;墙体厚度与材料的吸附净化活性之间存在协同效应,构建渗透反应墙时应根据墙体材料的吸附净化速率,合理确定渗透反应墙的厚度,以获得最佳的技术经济效果。
Underground coal gasification(UCG)is consistent with the development of low-carbon green transformation of energy in China.However,the groundwater pollution caused by it is the bottleneck preventing from the promotion and application of UCG.Permeable reaction barrier(PRB)is one of the research hotspots for in-situ groundwater remediation.In this paper,combined with the characteristics of UCG with shaft,the influence of PRB’s thickness and purification materials on the migration and dispersion of organic pollutants in groundwater,and purification and remediation were investig-ated by numerical simulation.On the foundation of the advection-diffusion equation(ADE),two hypotheses were intro-duced:①The mass transfer involved in the adsorption and purification of pollutants in groundwater is related to:(i)the difference potential between the concentration of pollutants adsorbed in the liquid and solid phases,(ii)the difference po-tential between the current adsorption concentration of solid phase and the potential maximum adsorption concentration,and(iii)the process time;②The strong adsorption ability of activated carbon may lead to the gradual accumulation of ad-sorption concentration in the solid phase and no longer easy desorption with the change of the external liquid phase con-centration.Both the migration of pollutants and the adsorption and purification processes were simulated numerically and validated experimentally after that the finite element method and-format iteration were adapted and the corresponding program were coded in MATLAB.The results show that the remediation is enhanced with the increase of the thickness of PRB,but at a declining acceleration,and the marginal effect of the wall thickness increase on the purification shows the diminishing trend.The stronger the adsorption and purification rate of the wall material is,the better the purification of the PRB on pollutants will be,and the adsorption and purification rate also shows a diminishing trend of marginal effect on the purification.There is a synergistic influence between the thickness and the adsorption activity of the material,thus the thickness of PRB should be determined reasonably according to the adsorption and purification rate of the material when constructing PRB in order to obtain the best technical and economic consequence.
作者
王凡
谌伦建
徐冰
马娇
邢宝林
苏发强
WANG Fan;CHEN Lunjian;XU Bing;MA Jiao;XING Baolin;SU Faqiang(Henan Key Laboratory of Coal Green Conversion,Henan Polytechnic University,Jiaozuo 454003,China;School of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,China;Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization,Jiaozuo 454003,China;School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2023年第4期1697-1706,共10页
Journal of China Coal Society
基金
国家自然科学基金-新疆联合基金资助项目(U1803114)
河南省科技攻关资助项目(212102311069)。
关键词
煤炭地下气化
地下水污染
渗透反应墙
迁移扩散
underground coal gasification UCG
groundwater pollution
permeable reaction barrier
migration dispersion
