Experimental Study On Preparation Of Dry Water Fire Extinguishing Materials Based On Compound Gel And Its Fire Extinguishing Efficiency

With the rapid development of the social economy,the incidence of fires in China is also increasing year by year.How to prevent and extinguish fires efficiently has become an important issue accompanying sustainable human development.In recent years,dry water,a kind of powder with high water content similar to dry powder,has attracted the attention of many scholars in the field of fire protection due to its simple storage and outstanding fire extinguishing efficiency.Dry water has a moisture content of up to 90% and excellent fire extinguishing performance,making it an excellent substitute for dry powder fire extinguishing agents.However,the research on using dry water materials as fire extinguishing materials is still in its initial stage,and the research results are not yet mature.There are problems such as unstable core shell structure of dry water,immature preparation process,and inability to synergize physical and chemical properties with fire extinguishing effectiveness.Based on this,the compound gel was applied to dry water materials in this thesis,the formula and preparation process of gel dry water were studied,the physical properties of the compound gel dry water materials were measured,and the influence mechanism of the compound gel on the physical properties of dry water was analyzed.The comparative experiment of fire extinguishing efficiency between compound gel dry water and different fire extinguishing agents was carried out,and its fire extinguishing mechanism for different fires was analyzed in depth.The main conclusions are as follows:(1)The formula of gel dry water was determined.In addition to fumed silica powder and deionized water,the formula of gel dry water also includes gel agent(carrageenan,xanthan gum and locust bean gum),cross-linking agent(potassium chloride)and preservative(ethyl paraben).(2)The preparation process of gel dry water was explored.The solid-liquid mass ratio directly affects the formation state of dry water,and high stirring speed and long stirring time can lead to excess input energy of the blades.Short stirring time can lead to insufficient input energy of the blades,and the size of the prepared dry water particles is not appropriate.The best preparation process of gel dry water is as follows: the solid liquid mass ratio is 8:100,the stirring speed is 11000 rpm,and the stirring time is set at45 s.(3)The effect of compound gel on the physical properties of dry water was studied,and its synergistic mechanism was clarified.The experimental results indicate that the proportion of particle size distribution of the prepared dry water between 100 and 400μm exceeds 75%;the bulk density of each dry water material is less than 0.5 g/m L,and the filling capacity needs to be improved.2-1 dry water,3-1 dry water,and 4-2 dry water exhibit excellent flow performance,with repose angles of 27.8°,27.9°,and 29.2°respectively.The compounding of gel agent can improve the compression resistance and water retention performance of dry water materials,which is attributed to the fact that the compounding of gel agent with proper proportion has a more stable skeleton structure through physical chemical crosslinking,which increases the strength of gel while the dehydration shrinkage of gel is weakened and the water loss is slowed down.(4)The extinguishing efficiency of different extinguishing materials was compared and analyzed,and the extinguishing mechanism of compound gel dry water was revealed.The order of extinguishing effectiveness of different extinguishing materials for suppressing Class B fires is: pure water dry water>3-1 dry water>2-1 dry water>4-2 dry water>dry powder>water-based extinguishing agent.The order of extinguishing effectiveness of different extinguishing materials in suppressing Class A fires is: 2-1 dry water>3-1 dry water>4-2 dry water>pure water dry water>dry powder>water-based extinguishing agent,and compound gel dry water has better effect on extinguishing class A fire.The mechanism of compound gel dry water material inhibiting Class A and Class B fires can be attributed to cooling,asphyxiation,isolation and chemical inhibition.There are 42 figures,19 tables and 92 references in this thesis.