Preparation method and key parameters of a environmentally safe foam for liquid fire suppression
[Objective]Liquid fuel fires are commonly extinguished using foam;however,conventional foam formulations include perfluorooctane sulfonate,which does not degrade easily,causing environmental pollution and posing a threat to human health.Furthermore,traditional foams exhibit poor thermal stability and are prone to reignition after extinguishing.Thus,developing a foam that is both safe and environmentally friendly while exhibiting strong resistance to reignition is urgently needed.However,most of the current research is limited to laboratory parameter measurements and mainly focuses on the development of new foams for solid fires,such as coal fires,which have considerable differences in fire suppression mechanisms and foam performance requirements from liquid fires.At present,research on highly stable and environmentally friendly foam formulations specifically designed for liquid fires is limited.This study aims to replace hazardous fluorocarbon surfactants with safe and biodegradable hydrocarbon surfactants and incorporate natural hydrophilic polymer guar gum to develop an environmentally friendly polysaccharide foam suitable for liquid fires.Analysis of the foaming and stability performance of the developed foam is conducted,and the concentrations and ratios of foaming agents and stabilizers are determined.Finally,the fire suppression performance of the developed foam is compared with that of the fluoroprotein foam(FFFP).[Methods]The foam expansion ratio and half-life were estimated,and the comprehensive values were computed to determine the optimal laboratory foam formulation with high comprehensive parameters.However,the direct estimation of the fire suppression time of the foam during liquid fire extinguishment was difficult as it was influenced by various factors such as foaming performance,stability,and flowability.Thus,a 0.8 m-diameter scaled-down oil pan was constructed,and the laboratory foam formulation with higher comprehensive parameters was further tested for its fire suppression performance and compared with the commercial FFFP.After complete extinguishment,a 5-minute cooling period was implemented,followed by an evaluation of the foam's resistance to reignition using a burn-back tank.[Results]The findings revealed that:(1)The foam presented the highest comprehensive value of 133.4 at an mass ratio of AEG and APG-0810 of 2∶8,with a mass fraction of 0.5％.The foam expansion ratio was 14.5,and the half-life was 10.8 min.(2)When the concentration of guar gum was 0.4％,the comprehensive value of the foam stabilized and exhibited the best fire suppression performance.The 90％control time was approximately 52 s,and the extinguishment time was 82 s.Comparing the control and extinguishment times of the developed foam with those of FFFP,the new formulation showed reductions of 16.1％and 10.9％,respectively.(3)At a guar gum concentration of 0.4％,the developed foam exhibited the best resistance to reignition.The 25％,90％,and complete reignition times compared to FFFP were extended by 96.5％,114.1％and 113.7％,respectively.[Conclusions]By replacing hazardous fluorocarbon surfactants with biodegradable hydrocarbon surfactants(APG-0810 and AEG)and introducing the natural hydrophilic polymer guar gum,the developed foam has improved viscous and water-retention properties,leading to a substantially improvement in its resistance to reignition.This study offers a reference for developing new reignition-resistant foam formulations specifically designed for liquid fires.
liquid fireguar gumenvironmentally friendly foamextinguishing timereignition time
万方数据
维普
