Experimental and molecular dynamics studies on the synergistic suppression of gas explosions in gas-solid media

Aiming at the problem that the traditional single-phase explosion suppression medium is not effective, it is proposed that the gas-solid two-phase medium cooperates with different explosion suppression principles to achieve efficient and rapid suppression of gas explosion. The method of using NaHCO3 powder and CO2 gas to synergistically suppress gas explosion was studied. The standard 20 L spherical explosion test device was selected, and the configuration optimization of reactants, transition states and products in the microscopic reaction mechanism of methane explosion was carried out by DFT (density funchtion theory). On this basis, the subsequent calculation was carried out. The results show that the single-phase medium with a volume fraction of 16% CO2 and 0.35 g/L NaHCO3 has an excellent effect on suppressing gas explosion, but the presence of 0.1 g/L powder will increase the maximum boosting rate by 17.9%. Compared with single-phase CO2 and single-phase NaHCO3 powder, the gas-solid two-phase medium explosion suppression phase reduces the maximum explosion pressure. When 8% volume fraction CO2 is used in conjunction with 0.125 g/L powder, the maximum explosion pressure of gas explosion is reduced by 72.42%, and the maximum pressure rise rate is reduced to 2.345 MPa/s. The suppression effect is optimal; however, when 4% volume fraction CO2 cooperates with 0.05 g/L powder, the maximum explosion pressure rise rate increases by 93.68%, and the reaction shows a certain intensification phenomenon. The quantum chemical calculation shows that in the process of gas-solid two-phase medium synergistic inhibition of gas explosion, the decomposition of NaHCO3 powder will absorb the heat in the reaction system, and its decomposition products will preferentially react with OH· and H· in the mixed system, hindering the generation of O·, inhibiting the chain process in the CH2O stage, and then inhibiting the transfer process of chain reaction. The CO2 produced by the decomposition of NaHCO3 powder and the CO2 in the mixed system dilute the volume fraction of methane in the mixed system, reduce the probability of collision between methane and oxygen molecules, and effectively inhibit the reaction process. © 2024 Explosion and Shock Waves. All rights reserved.