Study Of Fire Prevention And Extinguishing Performance Of Microcapsule Materials Used In Coal Mines

Coal mine fire extinguishing materials?e.g.inactive gas,inhibitor?play a great role in restraining the internal fire at present,but there are also their own limitations.Those materials are difficult to meet the higher requirements of people in the future for coal mine firefighting materials.For example,the injection volume of grouting material is large and it is difficult to drainage and discharge at later stage.The requirement of inactive gas on fire area is high.When inhibitor is injected into fire area,on the coal surface,its pulverulence is difficulty to be uniformly distributed and its aqueous solution is easy to lose.In this paper,ammonium polyphosphate?APP?is used as core material and melamine formaldehyde resin is used as wall material to make microcapsule extinguishing material by microcapsule technology.This paper has studied the fire prevention and extinguishing performance of this material.It provides a basis for field application of this material,and also provides a new direction for the research of fire prevention and extinguishing materials.By means of scanning electron microscopy,thermal analysis experiment,and Fourier transform infrared spectroscopy experiment,this paper characterized the surface characteristics and particle size of microcapsule material,testing moisture absorption,functional groups and decomposition process of microcapsule material,and analysising the inhibition mechanism of microcapsule material.The experimental results showed that the moisture absorption rate of the microcapsule material under the air of 85%-95%humidity is only 3.56%,the particle size is less than 20?m,and the decomposition temperature is 151.1?.The effect of microcapsule materials on the active functional groups of coal molecules was investigated in the process of temperature rise by Fourier transform infrared spectroscopy?FTIR?.Microcapsule material can not only reduce the quantity of hydroxyl and aliphatic hydrocarbons in coal,but also strengthen the stability of side chain,oxygen functional groups and all kinds of unstable ring of aromatic hydrocarbons and-CH₃/-CH₂-of methoxy.This postpones the heating process of coal oxidation.The effect of microcapsule material on coal oxidation parameters,such as coal characteristic temperature and heat quantity,was studied by synchronous thermal analysis.The results showed that microcapsule material can effectively improve the ignition temperature,the temperature of maximum weight loss rate and the temperature of maximum heat release rate in the process of coal combustion,reducing weight loss,weight loss rate,heat release rate and heat release,and increasing coal heat absorption.In the same coal sample,when the mass ratio of coal and microcapsule material is 4:1,the effect of microcapsule material on coal oxidation process is the best.The fire extinguishing performance of microcapsule materials was studied by experiment of inhibitory action of microcapsule material on coal spontaneous combustion.The results showed that,when the application concentration of microcapsule material,as fire extinguishing material,is 718.4 g/m²,the quenching time is shortest,the average cooling rate is larger and the overall inhibition effect is best.Under the same coal sample and the same application amount,compared with water,the quenching time of microcapsule materials is shorter,the average cooling rate is larger and the overall inhibition effect is better.