Explosion characteristics of shale gas in air

In this work, explosion characteristics of stoichiometric shale gas were studied employing a standard 20-L explosion bomb. Shale gas was represented by methane/ethane, methane/propane, and methane/ethane/propane mixtures, and the effect of fuel compositions, the volume fraction of ethane (or propane) increases from 0 to 0.42, on explosion parameters was examined. Results show that the maximum explosion pressure, the maximum explosion pressure rising rate, and the laminar flame speed increase with the volume fraction of ethane (or propane). The reason is that the increment of ethane (or propane) volume fraction increases the mole fraction of [H + O + OH]max. For a given volume fraction, propane provides more heat and H, O, and OH radicals, and consequently, propane shows a more robust incentive function on explosion parameters. Finally, the CH ratio, which is defined as the ratio of total carbon atoms and hydrogen atoms, is used to further study the explosion characteristics of various fuel compositions. There is a robust linear relationship between the CH ratio and explosion parameters. For laminar flame speed, however, the global fit curve provides poor accuracy while the local fitting curves coincide well with the data. This indicates that the laminar flame speed is more sensitive to the gas species.