Experimental Study On CO₂Adsorption Characteristics Of Coal Sample Spontaneous Combustion In Lu’an Coal Mining Area Typical Coal Seams

Lu’an group is one of seven big coal enterprise group in Shanxi Province,at present, the main mining area is mainly mined coal mine in Shanxi group inthe lower3#coal seam,3#coal seam structure is relatively simple, yetspontaneous combustion occurred, but the coal seam has been close to resourcesdry up, in the lower part of the Taiyuan formation of15#coal seam, is high-sulfur,phosphorus, high-ash, high calorific lean coal, high sulfur coal would increasethe danger of spontaneous combustion. Mine using mechanized coal caving arts,side by side off the coal mining exploitation, and lower recoveries coalface, leftmany coal mining is a major source of coal spontaneous combustion hazardcombustion, and after part after mine resource integration in the mining processor have appeared in the surrounding area is too small gob of coal spontaneouscombustion, spontaneous combustion Lu’an mining underground mining hasbecome a major highlight during a security risk, a serious threat to the safety ofmine production and development. Although the inert gas fire extinguishing iswidely used in the coal seam fire prevention practice, but the development ofoxidation of coal spontaneous combustion process of CO2inhibitionperformance of the relevant basic research is not sufficient, therefore, it isnecessary to have launched more depth and meticulous research.This paper aiming Lu’an spontaneous combustion or liable to spontaneouscombustion of mining coal seam characteristics and mining conditions, through laboratory research Lu’an mining coal seams typical CO2adsorption rate ofoxygen consumption before and after, CO production rate variation index gas,temperature and other characteristics of spontaneous combustion characteristicparameters. The main findings of this paper are as follows:(1) Analysis of coal spontaneous combustion fire prevention and controltechnology research status at home and abroad, and CO2as the inert gassuppression mechanism of spontaneous combustion of coal seam, as theresearch Lu’an mining area coal seam coal samples before and after adsorptionCO2natural features provide a theoretical basis.(2) On the Yiyuan mine, Fusheng mine, Luning mine, Wuyang mine, Yuwumine etc. CO2adsorption experiments were temperature programmed oxidation,and gaseous products generated during the heating process of the law ofcomparative analysis, the experimental results show that: First of all, beforeadsorption CO2, the CO and C2H6in the raw coal were started to appear at thetime of initial30℃;In H2of the initial temperature of130~160℃; GenerateC2H4initial temperature was between120~160℃, and generation increased withthe temperature rise was single. The second, after the adsorption of CO2, thesame temperature conditions, coal samples under different CO2concentration inthe atmosphere in three kinds of oxygen consumption rate decreases with theincrease of CO2concentration, the temperature of CO in the oxidation process ofcritical temperature did not change, the trend of the exponential rise slow.Thethird,30%concentration of CO2adsorption rate of coal samples are produced inthe heating process CO has started to have a decreasing trend, reduce the amountof CO produced before about the adsorption rate of20%~25%; Compared withthe previous adsorption, produced C2H4initial temperature lags10~20℃, andproduced H2and the lag of C2H4initial temperature20℃or so; The CO2generated curve changed, along with the coal temperature rising was "U" glyph.(3) Using of thermogravimetry-differential thermal analysis experiments of coal samples in different concentrations of CO2adsorption characteristics beforeand after the temperature variation, obtained before adsorption, five differentcoal seam water evaporation to make the corresponding temperature T1=94.2~99.4℃, coal samples of different oxygen uptake between0.36~0.58mg, ignitiontemperature T3is408.2~448.6℃. In addition to more than Yuwu coal at700℃of burning temperature, the rest of the coal sample burning temperature T4is572.8~608.6℃. After adsorption, the characteristic temperature points T1lag,lag temperature10~15℃, ignition temperature T3and T4burnout temperaturevarying degrees of delay, delay temperature40~75℃. Coal sample after CO2adsorption characteristic temperature point appeared the phenomenon of movingin the direction of high temperature, coal oxidation heat emission performance.Under the same conditions, CO2concentration, the higher the better inhibitoryeffect.(4) By Yiyuan coal mine sample after CO2and N2adsorption temperatureprogrammed oxidation experiment contrast analysis, and combining with thecharacteristics of CO2and N2for fire extinguishing, CO2, N2adsorptioncomparison sample and raw coal sample oxygen consumption characteristics inthe process of temperature programmed oxidation and spontaneous combustioncharacteristic parameters changed, the experimental results show that: in the lowtemperature phase oxidation of coal N2adsorption100%concentration of thesample after the same concentration of CO2than coal adsorption sample afterthe heating process in the oxygen consumption rate and CO production rateshould be large, temperature during150~220℃,100%after the concentration ofCO2adsorption of coal sample in the process of temperature rise rate of oxygenconsumption rate and CO are more significant decreasing trend. Therefore, inthe inerting inhibition of spontaneous combustion of coal seam fire on theadvantages of CO2is better than N2effect, and more conducive to preventionand control of coal seam fire. In this paper, to improve fire prevention and related CO2technology system,enrich and improve the inert gas fire prevention technology, reducing thenumber of naturally occurring Lu’an coal mine, mine fire prevention and toimprove the level of technology and equipment has important scientific andpractical significance.