The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

332 / 2018-05-17 22:17:38

Study on Seepage Law of CO2 in Loose Coal

Mass and heat transfer, Nonlinear seepage, Permeability, Non-Darcy coefficient, Numerical simulation

Mine occupational health and environmental safety > Fire protection

The liquid CO2 has a significant inert and cooling effect on the preventing and controlling coal mine fire. The seepage law of CO2 in loose coal is the basis for analyzing the process of heat and mass transfer. To analyze CO2 gas seepage law in loose coal under pressure conditions, an experimental apparatus is established under different particle diameters of coal, injection pressures and porosities. The results show that the seepage characteristic of CO2 is obviously non-linear in loose coal, and in consistent with non-Darcy theory; Compared with the porosity and pressure, the particle diameter of coal is a key factor influencing the seepage characteristics; The density and the dynamic viscosity of CO2 increase with injection pressure, and the permeability of CO2 increases in the coal while the non-Darcy coefficient decreases, so it has little effect on the seepage of CO2 in loose coal. Fitting result indicates that both the permeability and the non-Darcy factor are exponentially related to porosity and particle size, and the general theoretical equation for describing CO2 gas seepage in loose coal is obtained based on particle size and porosity. Furthermore, based on Darcy flow and non-Darcy flow theorem, the numerical simulation of CO2 cooling in loose coal is carried out, which provides a theoretical basis for establishing an accurate model of carbon dioxide cooling in loose coal.