| Coal is the most important one-off energy besides oil and natural gas,and occupies an important position in the energy structure of national economy.However,there was coal spontaneous combustion in more than half of the state-owned key coal mines in China.Coal spontaneous combustion often causes mine fire,but also often induces gas and coal dust explosion,which seriously threatens the safety of miners and brings great disasters to the mine.Therefore,prevention and control of coal spontaneous combustion is the focus of coal mine fire prevention work.In this paper,two kinds of coal spontaneous combustion prevention materials were designed,and their preparation process and fire-fighting performance were studied.1.The expanded THPP was prepared by using three(2-hydroxyethyl)isocyanurate(THEIC)and ammonium polyphosphate(APP)to prevent coal spontaneous combustion,the effect of THPP on the thermal behavior of coal samples was studied,and the THPP was studied the resistance performance and fire-fighting performance.The results show that the addition of 30%mass fraction of THPP to coal samples,and when the addition ratio of THEIC to APP is 1:2,has the greatest impact on the thermal behavior of the coal samples,and the carbon content is up to 44.1%,which is nearly 5.7 times higher than that of 6.6%of raw coal;the inhibition test results of coal sample show that the inhibition rate of coal is 56.5%at 200? after THPP treatment,and the higher inhibition rate indicates that it has good inhibition on the prevention and control of CSC;self-built experimental platform for extinguishing coal pile fires,and THPP materials were tested for fire prevention and extinguishing.The results showed that it effectively inhibited the combustion of coal;based on the oxidation kinetic equation,the activation energy value of raw coal was calculated to be 168.4 kJ/mol,and the activation energy of the coal sample increased to 283.1kJ/mol after THPP treatment,which increased by 68.1%.The increase in activation energy means that the oxidation reaction of the coal sample is more difficult to proceed,and the macroscopic manifestation is that the coal is more difficult to spontaneously combust;scanning electron microscope(SEM)showed that the THPP treated coal sample formed an expanded carbonized layer during the combustion process,which effectively inhibited the mutual transfer of heat,oxygen and combustible volatiles in the coal,and prevented the further combustion of the coal.2.In view of the disadvantages of traditional water glass(WG)gels such as low strength,easy colloid cracking,easy loss of slurry,etc.,polymer A is introduced into the WG gel,then cross-linking agent B is added to the A/WG gel,finally The A-B/WG gel formed by the interpenetrating network of water glass and high molecular polymer was prepared.Through the study of the gel forming time,gel strength,plugging performance,microscopic morphology and chemical resistance of the composite gel,its excellent fire-fighting performance is revealed.The results show that the addition of polymer A significantly improves the strength and water retention of the WG gel,and the A-B/WG gel still maintains good stability after one week,which solves the problem of cracking and breaking of the mining WG gel after losing water;Changing the amount of coagulant added can realize that the gelation time of the slurry can be adjusted from 1 min to 30 min;The SEM shows that A-B/WG gel has a denser and more continuous skeleton structure than WG gel.The inhibition rate of A-B/WG gel is as high as 69.1%,which is 3.7 times higher than that of WG gel(14.7%).It is further confirmed by fire-fighting experiments that the gel can effectively inhibit coal combustion.Figure[26]Table[12]Reference[111]... |
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