The inhibitory combustion reaction performance and tail gas analysis of composite ultra-fine dry powder extinguishing agent containing different additives

For lack of an extinguishing agent with high-efficiency, non-toxic and environmentally friendly, a new type of extinguishing agent was fabricated to solve such an urgent problem. In this study, the zinc borate (ZB) and ferrocene (Fe(Cp)₂) were utilized as two additives for extinguishants to suppress combustion reaction and the toxicity of the tail gas was detected. The mass fraction of ZB corresponding to the optimal inhibitory effect was determined to be 0.5–1.5%, by contrast, the optimum interval of Fe(Cp)₂ was detected as 0.5–1.0%. Similarly, with the increasing proportion of the two additives, the homologous inhibitory action was gradually weakened. From the perspective of thermogravimetric analysis (TGA), it was indicated that the ZB accelerated the pyrolysis process of the extinguishant, making its thermal decomposition process more thoroughly. Meanwhile, the differential scanning calorimetry (DSC) demonstrated that the decomposition efficiency was markedly improved when the amount of ZB was maintained at 0.5–1.5%. Besides, the tail gas tests were implemented to assess the extent of toxic and harmful properties. In terms of the carbon monoxide (CO) and carbon dioxide (CO₂) generated, once the mass fraction of ZB and Fe(Cp)₂ was less than 1.5% and 1.0% respectively, the concentration of CO and CO₂ was distinctly lower than that without additives. Moreover, the inhibitory ability on nitrogen oxides (NOx) was enhanced when the mass fraction of the two additives was kept below 1.0%. The results confirmed that a more practical extinguishant was proposed and it can provide guidance for the application and development of extinguishants.     

Extinguishing pool fires with aqueous ferrocene dispersions containing gemini surfactants

The objective of the present study was to explore the relationship between the dispersibility and fire-extinguishing capability of aqueous ferrocene dispersions containing gemini surfactants belonging to the same series, namely, olfin E1020, olfin PD 201, and surfynol 465. In this study, the dispersibility and ability to suppress pool fires were characterized by turbidity and extinguishing time, respectively. Ultrasonication enabled easy preparation of the aqueous dispersions of ferrocene powder containing the gemini surfactants. Visual observations and turbidity measurements clearly demonstrated that the order of dispersibility was as follows: ferrocene dispersion containing surfynol 465 ≥ ferrocene dispersion containing olfin E1020 > ferrocene dispersion containing olfin PD201. Fire suppression experiments indicated that the ferrocene diameter, in the ferrocene diameter range of 10.4–21.5 μm, negligibly influenced the extinguishing time. Furthermore, for the same ferrocene samples as were used for the turbidity measurements, the order of extinguishing ability was as follows: ferrocene dispersion containing surfynol 465 > ferrocene dispersion containing olfin E1020 > ferrocene dispersion containing olfin PD201; thus, the extinguishing ability was identical to the dispersibility order.