Experimental Study On Mic Rocapsule Sodium Salt Inhibitor For Preventing Coal Spontaneous Combustion

Sodium salt inhibitor(SSI)is a new type of water-absorbing inhibitor,often used in mine fire prevention.But SSI has the problems of pungent odor and high moisture absorption rate under normal temperature conditions.Thus,SSI is more prone to cause inhibitor waste.Therefore,in this study,SSI is modified by microencapsulation,to reduce the moisture absorption rate and improve the efficiency.Microcapsule sodium salt inhibitor(MSSI)was successfully prepared melting dispersion and condensation method,with polyethylene glycol 20000(PEG-20000)as the wall material and SSI as the core material.Microcapsule modification can reduce the moisture absorption rate of SSI at normal temperature conditions.When the mass ratio of wall material to core material is 2:1,the moisture absorption rate is reduced by 67.3%;The initial decomposition temperature of SSI and MSSI are 753.1 ? and 384.5?,and thermal stability of MSSI is reduced.The thermogravimetric and temperature-programmed experiments was applied to exlplore the oxidation characteristics of coal samples treated with inhibitors.SSI and MSSI can inhibit coal spontaneous combustion.With the increase in temperature,the oxygen consumption rate,CO generation rate,and CO2 generation rate of the raw coal and coal samples treated with inhibitors increase exponentially.and the values of coal samples treated with inhibitors are lower than those of raw coal.Under the experimental conditions,15%concentration MSSI has the best inhibitory effect on low-temperature oxidation of Hei Gou coal samples.Compared with raw coal,the apparent activation energy of water evaporation and gas desorption stage increased by 64.7%,and oxygen absorption weight gain stage increased by 56.9%;the average inhibition rate of 15%MSSI is 66.6%,and the highest inhibition rate at 110? reached 83.8%.The infrared spectroscopy was used to test the influence of MSSI on the inhibition characteristics of coal samples during the heating process.At the beginning of the experiment,PEG-20000 can react with the hydroxyl and carbonyl-containing active components to reduce coal sample oxidation active functional group content,inhibit coal self-ignition oxidation.As the temperature of the coal sample increases,PEG-20000 melts and covers the surface of the coal,and the sodium salt inhibitor of the core material is gradually exposed to the air,achieving inhibition by isolating oxygen and absorbing moisture.