碱土金属和沙柳对煤热解过程中协同作用的影响

Synergistic Effect of Alkali Metals and Biomass on Coal Pyrolysis

利用热重微差分析仪对碱土金属和沙柳对宝矿煤热解过程中的协同作用进行了探究。研究表明:当宝矿煤中加入沙柳时,在200~600℃,宝矿煤热解初温降低,热解区间变小,最大失重速率增加,失重比例增加;而在600℃以上时,沙柳对宝矿煤热解无明显影响。当宝矿煤中加入氧化钙时,在200~600℃宝矿煤热解初温无明显变化,但最大失重速率增加,且随氧化钙的比例增加,其变化效果越明显;在600℃以上时,氧化钙的加入可以进一步促进宝矿煤的热解,但氧化钙占比改变,对宝矿煤的热解区间,最大失重速率影响不大。将热力学数据按照Coast-Redfern积分法进行动力学拟合,其符合一级反应动力学模型,当在宝矿煤中加入氧化钙与沙柳后,可以显著降低宝矿煤的热解活化能。且随着氧化钙比例增加,活化能逐渐降低,指前因子变得更小,表明氧化钙和沙柳均对宝矿煤的热解过程产生了协同作用。

The effects of alkali metals and biomass(of Salix psammophila)on the pyrolysis of coal from Baokuang Coal Mine were investigated in the experiments with thermogravimetric millisecond differential analyzer.The experimental results show that when Salix was added to the coal,at 200 to 600℃,the maximum weight loss and the weight loss ratio increased.above 600℃,Salix had no obvious effect on the pyrolysis of the coal.When calcium oxide was added,at 200 to 600℃,there was no obvious change in the initial temperature of the coal pyrolysis,the maximum weight loss rate increased,and the effect was more obvious with the increase in the proportion of CaO.above 600℃,the pyrolysis of the coal mine was promoted,the maximum weight loss rate and the pyrolysis interval were affected slightly by the proportion of calcium oxide.In addition,the data of combustion in the Coast-Redfern integral method were fitted and the results conform to the first order reaction kinetics model.Therefore,adding calcium oxide and Salix into coal could significantly reduce the activation energy of the coal pyrolysis.With the increase of the proportion of calcium oxide addition,the activation energy gradually decreased,and the pre-exponential factor became smaller,indicating that both calcium oxide and Salix adding have synergistic effect on the pyrolysis process of the coal.