The inhibition of CO2 twin-fluid water mist with modified inorganic salt on LPG explosion: Experimental tests and simulations

To further enhance the explosion suppression effect on LPG, four surfactants including SDS, APG0810, FS-50, and AFFF were used to modify K2CO3 and FeSO4 inorganic salts, and CO2 twin-fluid water mist with modified inorganic salt were conducted to suppress LPG explosions. The results showed that surfactants have selectivity in increasing the explosion suppression effect of inorganic salts. After modifying K2CO3, the explosion suppression effect was further enhanced under most conditions; however, after modifying FeSO4, the explosion suppression effect was weakened. The optimal explosion suppression condition was a water mist containing 5 % K2CO3 + 0.1 % FS-50 + 0.2 % SDS, which reduced the pressure peak by 44.5 % and the average flame propagation speed by 84.7 % compared to 6 % LPG. Thermogravimetric experiments and mechanism analysis revealed that the addition of surfactants alters the pyrolysis characteristics of inorganic salts. For K2CO3, surfactants promote its pyrolysis process, increasing the heat absorption; for FeSO4, the opposite is true. Chemical kinetics simulations found that during the explosion suppression reaction of CO2 and water mist with modified inorganic salt, the generation rates of three active radicals, O, H, and OH, were significantly reduced compared to single suppression conditions, thus suppressing the LPG explosion reaction.