呼伦贝尔煤与3种富氢有机物共热解相互作用研究

Study on the co-pyrolysis interaction of Hulunbeier coal and three hydrogen-rich organic compounds

通过考察呼伦贝尔煤与3种富氢有机物(纤维素、聚乙烯吡咯烷酮(PVP)、高密度聚乙烯(HDPE))共热解过程热失重、自由基浓度、固定床热解产物产率变化,并与单独热解对比,解析共热解过程中不同原料热解产生的自由基碎片在逸出床层过程中的相互作用。试验发现,煤/纤维素、煤/PVP、煤/HDPE共热解在150~600℃的失重量分别为61.18%、60.26%和64.31%,均低于计算值62.55%、63.53%和66.76%;温度高于400℃时,共热解过程自由基浓度试验值均低于计算值(单独热解结果平均值);固定床热解试验中,固体产率分别为37.9%、39.0%和34.0%,与计算值(37.5%、36.5%和33.6%)相当或略高,液体(包含水和焦油)产率试验值分别为33.3%、44.9%和53.2%,均低于计算值(39.8%、51.3%和57.1%),气体产率试验值分别为28.8%、16.1%和12.9%,均高于计算值(22.7%、12.2%和9.3%)。因此共热解过程中,不同原料热解产生的自由基碎片在逸出床层过程中会相互作用,挥发性自由基和稳定自由基之间的结合最明显,挥发性自由基逸出阻力增加,二次反应增大。

In this paper,the Hulunbuir coal and three hydrogen-rich organic compounds(cellulose,polyvinyl pyrrolidone(PVP),and high-density polyethylene(HDPE))were used as raw materials to investigate the behaviors of thermogravimetric,the changes of free radical concentration,and the changes of the yield of pyrolysis products on the fixed bed of the co-pyrolysis process and compare with the results of single pyrolysis.The interaction of free radical fragments produced by pyrolysis of different raw materials during the copyrolysis was analyzed.The results show that the weight loss of co-pyrolysis of coal/cellulose,coal/PVP,and coal/HDPE at 150-600℃are 61.18%,60.26%,and 64.31%respectively,which are all lower than the calculated values of 62.55%,63.53%,and 66.76%;When the temperature is higher than 400℃,the experimental value of free radical concentrations in the co-pyrolysis process are all lower than the calculated value(an average of individual pyrolysis results);According to fixed-bed pyrolysis results,the solid yields are 37.9%,39.0%,and 34.0%,respectively,which are equal to or slightly higher than the calculated values(37.5%,36.5%,and 33.6%),the liquid(including water and tar)yields are 33.3%,44.9%,and 53.2%respectively,which are all lower than the corresponding calculated values(39.8%,51.3%,and 57.1%),and the gas yield are 28.8%,16.1%,and 12.9%,which are all higher than the calculated values(22.7%,12.2%,and 9.3%).During the co-pyrolysis process,the free radical fragments generated from different raw materials will interact with each other in the process of escaping from the bed.Among them,the combination of volatile free radicals and stable free radicals is the most important.The resistance of volatile free radicals increases,leading to an increase of the secondary reaction of the volatiles.