垃圾填埋气体抽排影响半径的预测  

Estimation of radius of influence of pumping landfill gas

作　　者：刘磊[1] 梁冰[1] 薛强[1] 赵颖[2] 王永波[2] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]辽宁工程技术大学力学与工程学院,辽宁阜新123000

出　　处：《化工学报》2008年第3期751-755,共5页CIESC Journal

基　　金：国家自然科学基金项目(50309015,50374041);湖北省自然科学基金青年杰出人才项目(2006ABB039);中国科学院岩土力学重点实验室开放课题(Z110602);辽宁省高校创新团队项目~~

摘　　要：垃圾填埋气体迁移是对流和扩散效应共同作用的结果。以多孔介质渗流力学和溶质运移理论为基础,结合垃圾填埋气体(LFG)产气特征,推导了二维极坐标下LFG迁移控制方程,给出了LFG影响半径的计算模型,实现了对气井影响关径Ri的预测及模型参数的灵敏度分析。结果表明,垃圾土渗透率的增大使气体流量增多,进而扩大了LFGRi;扩散效应所引起的气体流量在径向分布相差较大,是导致不同扩散系数条件下Ri变化的主要原因。扩散系数越大使外部与井口流量比值越小,导致LFGRi越小;LFGRi随易降解有机物比例的降低而扩大,但增幅较小。在填埋高度≤10m的情况下,有机物组分含量对LFGRi的影响并不明显。Ri技术指标的确定可为垃圾填埋场气井设计及LFG资源化开发利用及评价提供技术参数。The combined action of convection and diffusion leads to the landfill gas （LFG） transport in landfill. Based on the seepage mechanics and solute transport theory of porous media, the governing equation of LFG migration was deduced in the two-dimension scalar coordinate with LFG generation characteristic model. And the computation model of radius of influence for LFG was given. Estimation of radius of influence of gas well and sensitivity analysis of model parameters were presented. The results showed that the gas flux increased with increasing permeability, so as to enlarge the Ri （radius of influence） of LFG. The LFG flow rate was greatly different in the radial direction, caused by the gas diffusion effect, and was the main factor leading to the variation of Ri at different diffusion coefficients. The ratio of flux in outside and hole mouth decreased since the diffusion coefficient of gas in pore increased, leading to smaller Ri. The Ri became larger with decreasing readily biodegradable proportion, but the increasing rate tended to be smaller. Once the landfill height was ≤10 m, the influence on Ri by biodegradable content was not obvious. The determination of LFG Ri will provide the technical data for gas well design and exploitation and evaluation for LFG reuse.

关 键 词：垃圾填埋气体 影响半径 数学模型 灵敏度分析 预测 

分 类 号：TV139.14[水利工程—水力学及河流动力学]