Experimental study on suppression of hydrogen jet flame by solid-liquid two-phase composite powders containing core-shell structure

With the rapid development of the global hydrogen energy industry, the issue of hydrogen energy safety has attracted much attention. To cope with the potential risks and challenges, there is an urgent need to strengthen the research, development and application of hydrogen energy fire protection technology. In this study, the core–shell structural solid–liquid composite fire extinguishing powders (CSSLP) containing ammonium dihydrogen phosphate (ADP) and potassium bicarbonate (PTB) are prepared. The determined process parameters for optimal preparation of powders are solid–liquid mass ratio of 1:10, stirring speed of 8000 rpm and stirring time of 40 s, respectively. As for the suppression of explosive overpressure, the results show that the CSSLP-ADP presents the strongest inhibitory capacity when the hydrogen release pressures are 2.0, 4.0, and 6.0 MPa, corresponding to peak overpressure inhibition rates of 89.11 %, 74.82 %, and 81.55 %, respectively. However, the overpressure suppression efficiencies of CSSLP-PTB only reaches 53.09 %, 45.43 % and 61.64 %, respectively, under the same pressure conditions. Furthermore, the CSSLP-ADP exhibits the relatively highest suppression efficiency of 15.36 % for the average velocity of jet flame front propagation at a release pressure of 2.0 MPa. Meanwhile, combined with the results of fire extinguishing, pyrolysis and characterization experiments, the physicochemical synergistic inhibition mechanism of CSSLP-ADP is revealed and predicted. This study can effectively promote the safe development of the hydrogen energy industry and also provide effective countermeasures for the prevention of hydrogen safety accidents.