CO_(2)-N_(2)复合惰气对氧化煤冷却惰化特性研究

Study of Inerting Characteristics of CO_(2)-N_(2) Composite Inert Gas for Cooling of Oxidized Coal

为对比分析不同比例CO_(2)-N_(2)复合惰气和纯CO_(2)/N_(2)对氧化煤惰化效果,利用程序升温实验系统,分别对比煤处于临界温度和干裂温度下通入纯CO_(2)/N_(2)和CO_(2)-N_(2)复合气体后O_(2)、CO气体浓度和煤温的变化特征。结果表明:在氧化煤冷却过程中,相同注气流量下,CO_(2)含量占比高于N_(2)时表现出更快的降温速率、更大的O_(2)和CO浓度降幅以及活化能;以临界温度为初始煤温时,30%N_(2)+70%CO_(2)的降氧速率高于10%N_(2)+90%CO_(2)和纯CO_(2)为0.4~1.22 mol/(cm^(3)·s),CO下降速率高于10%N_(2)+90%CO_(2)和纯CO_(2)为0.24~0.72 mol/(cm^(3)·s),且活化能高于其他5种惰气0.6~5.6 kJ/mol;以干裂温度为初始煤温时,且30%N_(2)+70%CO_(2)的降氧速率高于10%N_(2)+90%CO_(2)和纯CO_(2)为0.22~2.29 mol/(cm^(3)·s),CO下降速率高于10%N_(2)+90%CO_(2)和纯CO_(2)为0.02~5.7 mol/(cm^(3)·s),且活化能高于其他5种惰气为1.3~6.5 kJ/mol。综合降温速率、标志性气体浓度、下降速率及活化能等参数,采用30%N_(2)+70%CO_(2)复合气体对煤体的冷却惰化效果最优。

In order to compare and analyze the inerting effects of different ratios of CO_(2)-N_(2) composite inert gas and pure CO_(2)/N_(2) on the oxidized coal,the characteristics of O_(2) and CO gas concentrations and coal temperature changes after passing pure CO_(2)/N_(2) and CO_(2)-N_(2) composite gas at the critical temperature and dry cracking temperature,respectively,were compared using the programmed warming experimental system.The results show that in the cooling process of oxidized coal,with the same gas injection flow rate,CO_(2) content with a higher percentage than N_(2) exhibits faster cooling rate,larger O_(2) and CO concentration drop and apparent activation energy;with the critical temperature as the initial coal temperature,the oxygen drop rate of 30%N_(2)+70%CO_(2) is higher than that of 10%N_(2)+90%CO_(2) and pure CO_(2) is 0.4-1.22 mol/(cm^(3)·s),the rate of CO drop is higher than 10%N_(2)+90%CO_(2) and pure CO_(2) is 0.24-0.72 mol/(cm^(3)·s),and the apparent activation energy is higher than the other five inert gases is 0.6-5.6 kJ/mol;when the dry cracking temperature is the initial coal temperature,and the rate of oxygen drop of 30%N_(2)+70%CO_(2) is higher than 10%N_(2)+90%CO_(2) and pure CO_(2) is 0.22-2.29 kJ/mol;CO drop rate is higher than 10%N_(2)+90%CO_(2) and pure CO_(2) is 0.02-5.7 mol/(cm^(3)·s),and the apparent activation energy is higher than the other five inert gases is 1.3-6.5 kJ/mol.Combining the parameters of drop rate,symbolic gas concentration,drop rate and activation energy,using 30%N_(2)+70%CO_(2) composite gas is the best for the cooling inerting of the coal body.