Experimental research on the suppression of hydrogen deflagration by flame-retardant composite ultrafine dry powder fire extinguishing agents containing aluminum hydroxide

With the rapid development of the hydrogen energy industry on a global scale, the safety risks posed by hydrogen leaks or accumulations cannot be ignored. Therefore, the development of new hydrogen deflagration inhibitors can provide more comprehensive and reliable safety guarantees for chemical production. In this paper, a novel kind of efficient composite dry powder is prepared by compounding aluminum hydroxide (Al) with ordinary ultrafine dry powder extinguishing agent (ODPEA). The experimental platform of pure hydrogen explosion suppression is established to test the suppression efficiency and action law of different extinguishing agents. The results indicate that under the conditions of hydrogen release pressure of 2.0, 3.0 and 4.0 MPa, the peak overpressure suppression rates of ODPEA are 49.45 %, 50.76 % and 35.27 %, respectively. In contrast, the overpressure peak inhibition rates of ODPEA containing Al (ODPEA-Al) are significantly improved, which are 71.08 %, 69.48 % and 54.99 %, respectively. In addition, when the hydrogen release pressure is 2.0 MPa, the suppression rates of ODPEA and ODPEA-Al on the hydrogen jet flame front propagation speed reach 42.75 % and 53.35 %, respectively. Moreover, the experimental results of the characterization and pyrolysis tests demonstrate the relatively higher dispersion and pyrolysis degree of ODPEA-Al particles, as well as the stronger heat absorption capacity. Thus, the physicochemical synergistic inhibition mechanism of ODPEA-Al on the deflagration process of pure hydrogen is elucidated and hypothesized. The application of hydrogen deflagration inhibitors in this study can help reduce the number of safety accidents in chemical production processes, thereby observably enhancing the safety, stability, and reliability of chemical production, and promoting the sustainable development of the chemical industry.