Study on the Mathematical Model of Gas Preferential Flow of MSW

Abstract

Municipal solid waste (MSW) has various components, different sizes and strong heterogeneity. The significant preferential flow effect of MSW directly affects the migration path of landfill gas. In order to study the gas preferential flow characteristics of MSW, a mathematical model for describing gas preferential flow in the pore area and the fractured area was established. The whole process of gas passing through MSW sample was simulated by the established model. The simulation results showed that gas flow is not only related to the total permeability and total porosity of MSW, but also needs to consider the changes of the permeability and porosity of the pore area and fracture area.The peak value of gas breakthrough curve increases with the ratio of fracture to pore permeability, while the time of gas passing through MSW sample decreases with the ratio of fracture to pore permeability. The peak value of gas breakthrough curve decreases gradually with the decrease of the proportion of fracture area in pore space.