非饱和土质覆盖层多组分气体运移机理研究

为研究土质覆盖层中各组分气体的运移规律,进行了土柱注气试验,并通过多组分气体运移理论对试验结果进一步分析。分析结果表明:在注入气体总流量不变的情况下,改变注入气体的组分,会显著影响土柱中各组分气体分布;多组分气体运移理论能较好地预测各组分气体的运移;表观气相渗透系数不是一常数,与气压大小相关;体相扩散是影响各组分气体分布规律的主要因素,通过改变有效二元扩散系数,调整各组分气体分布,可以提高土质覆盖层中甲烷氧化效果。

Mechanism of multi-component gas migration in unsaturated cover

A multi-component gas migration model is presented for determining each component flux of landfill gas. The method to determine transport parameters in unsaturated soils is also given. A soil column test is conducted to simulate the progress of gas migration in landfill final cover. The test results are compared with the theoretical ones. It shows that the multi-component gas migration model can give the flux of each component more accurately. Change in the injected gas component fraction has a significant influence on the gas distribution in soils. Amount of apparent gas permeability depends on gas pressure. Bulk diffusion is the main factor to determine the distribution of each component in soils. Changing in effective diffusion coefficient may improve the methane oxidation capacity.