氧气浓度对褐煤吸附特性的影响研究

Study on Effect of Oxygen Concentration on the Adsorption Characteristics of Lignite

煤自燃是威胁矿井安全生产的重大灾害之一,而氧气对于煤自燃的发生及发展具有明显的调控作用,其中煤氧吸附是影响煤自燃反应的关键。因此,选取褐煤为研究对象,分别采用低温氮吸附法和红外光谱法研究了不同氧气浓度下煤孔隙结构参数和官能团的变化规律;采用PCTPro-C80联用试验法研究了氧气浓度对煤的氧吸附量和吸附热的影响。结果表明:煤的比表面积和孔隙体积随氧气浓度的升高整体表现为增大,煤孔隙体积主要以中孔为主;随着氧气浓度的升高,微观上—Ar—CH、—CH_(2)—CH_(3)、—OH等基团含量减少,宏观上煤吸氧量和吸附热整体表现为增多;当氧气浓度为13%时,煤的比表面积、孔隙体积、煤吸氧量和吸附热呈明显降低趋势,且—CH_(2)—CH_(3)基团的含量下降速率最快,下降值为18.11%。

Coal spontaneous combustion is one of the main disasters threatening the safety of mine production,and oxygen plays an obvious role in regulating the occurrence and development of coal spontaneous combustion,in which coal oxygen adsorption is the key step affecting coal spontaneous combustion reaction.Taking lignite as the research object,the change rules of coal pore structure parameters and functional groups under different oxygen concentrations were studied by low-temperature nitrogen adsorption method and infrared spectroscopy,respectively.The effect of oxygen concentration on oxygen adsorption capacity and adsorption heat of coal was studied by PCTPro-C80combined experiment.The results show that the specific surface area and pore volume of coal increase with the increase of oxygen concentration,and the pore volume of coal is mainly mesoporous.With the increase of oxygen concentration,the content of groups such as—Ar—CH,—CH_(2)—CH_(3)and—OH decreases on the micro level,while the adsorption capacity and adsorption heat of coal increase on the macro level.When the oxygen concentration is 13%,the specific surface area,pore volume,adsorption capacity and adsorption heat of coal show a decreasing trend,and the content of—CH_(2)—CH_(3)group decreases the fastest,with a decreasing degree of 18.11%.