Preparation And Fire-fighting Characteristics Of Nano ATH Three-phase Foam

Under the energy background of "carbon peak and carbon neutralization",China's coal industry will turn to the development route of "reducing output and improving quality".In order to improve the quality of coal mining safety and solve the problem of spontaneous combustion of coal in goaf,based on the traditional three-phase foam system,nano alumina(ATH)inorganic inhibitor was chosen as solid particle,and the foaming agent solution prepared by experiment was selected as liquid phase to form a stable nano ATH three-phase foam system under the action of nitrogen.Compared with the traditional three-phase foam,the foam system has significantly improved foaming and blocking properties,and has a strong smoke elimination performance.The research results of this paper are as follows:(1)A high performance anionic nonionic composite foaming agent has been developed through the analysis of foam properties and apparent morphology.When nonionic surfactants are mixed with suitable anionic surfactants,the surfactant molecules interspersed each other,which makes the gas/liquid interface molecules more tightly arranged,and can produce obvious synergistic reaction.The result shows that the surface tension decreases obviously,and the foaming and product stability is enhanced significantly.The optimum concentration of foam solution is determined by particle size analysis.When the foam concentration reaches the critical point,the surfactant molecules form micelles in the solution,and the foam diameter will mutate under the same foaming driving force.(2)Combining nanoparticles with foaming agents,the effects of nanoparticles on foaming properties,stability,interfacial properties and rheological properties of the foam were experimentally investigated.The experimental results show that the prepared composite foaming agent can react synergistically with nano aluminum hydroxide particles.Nanoparticles can enhance the Marangoni effect and improve the mechanical strength of the foam liquid membrane,so that the foam is not easily broken.When the concentration of nano aluminum hydroxide particles is 1.5%,the maximum modulus of viscoelasticity of foam is 3.08 mN/m.The highest volume of foam is 700mL.Nanoparticles can block the liquid film and form a three-dimensional network structure,which greatly improves the stability of foam.When the concentration of nanoparticles reaches 2%,the half-life of foam solution increases from 78S to 453s.The results of viscosity and rheological analysis showed that the nano ATH three-phase foam belonged to pseudoplastic fluid,and showed good stability under shear.The consistency of the system increased with the increase of nanoparticle concentration.(3)From the macroscopic and microscopic level,the resistance and smoke suppression properties of nano ATH three-phase foam are compared and analyzed.The experimental results show that compared with other inhibitor materials,the nano ATH three-phase foam has excellent low temperature resistance and high temperature flame retardance.Low temperature,nano ATH three-phase foam can extend the temperature of intersection point and inhibit the release of indicator gas.The change of functional groups of coal samples was inhibited during the heating process,and the oxidation heating process was delayed.Under the high temperature environment,the nano ATH three-phase foam can effectively reduce the weight loss rate and the maximum weightlessness rate of the coal sample,prolong the appearance time of the characteristic temperature points,especially the ignition temperature point,prolong the ignition time of the coal sample,weaken the intensity of the flame and the release of heat,and have good smoke elimination ability.Figure[47]table[10]reference[79]...