氧化钙对褐煤和无烟煤热解特性影响

Effect of calcium oxide on pyrolysis characteristics of brown coal and anthracite coal

为研究CaO对褐煤和无烟煤热解特性影响,采用实验室小型固定床反应器对锡林郭勒褐煤（X）和宁夏石嘴山无烟煤（SH）,进行热解实验,研究了CaO对热解三相产物分布规律影响。实验结果表明：在500~600℃时,添加2%CaO后褐煤热解生成CO_2的产率小于未添加CaO煤样热解生成CO_2的产率,添加CaO与否对其他3种气体H_2,CH_4,CO产率影响不大;与未加入CaO的褐煤煤样相比,加入CaO的褐煤煤样在相应温度下热解气相产物产率小幅度降低,且随着热解温度的升高,加入CaO的褐煤煤样气相产物产率增加速率大于未加入CaO的褐煤煤样。褐煤脱挥发分主要在600℃之前的热解阶段,而对于无烟煤来说,CaO在中温热解阶段对挥发分的脱除具有促进作用。对于褐煤半焦来说,加入2%CaO一直作为灰分存在半焦中,且随着热解温度的升高,褐煤半焦在高温时反应活性较高,发生热缩聚反应,导致半焦中有机质含量降低,以上2种原因直接导致褐煤半焦灰分升高;对于无烟煤来说,灰分增加主要是由于CaO的加入。

In order to explore the effect of calcium oxide on pyrolysis characteristics of brown coal and anthracite coal, the changes of the pyrolysis products distribution were analyzed based on Inner Mongolia Xilinguole lignite and Ningxia anthracite coal（ Xilinguole lignite and Ningxia anthracite coal were denoted as X and SH, respectively）, and the experiments were carried out with a fixed bed reactor. Research results show that the yield of CO2 generated by lignite after addition of CaO is lower than that of not adding CaO between 500 ℃ and 600℃, and the CaO has little effect on the yield of the other three gases. Compared with the lignite without CaO, the yield of gas product decreased corresponding tempera-ture for lignite with the addition of CaO, and increase rate of gas yield for the lignite with CaO was higher than that of without CaO with the increase of pyrolysis temperature. The removal of volatile matter from lignite was mainly in the stage of pyrolysis of 600 ℃, while for anthracite, CaO plays a promoting role in removal of volatile in the medium temperature. For lignite char, the added 2% CaO has been used as the ash in the presence of char. High activity reaction of lignite char at high temperature, thermal condensation reaction occurred, resulting in the decrease of organic matter content in char with the increase of pyrolysis temperature. The above two reasons led directly to the lignite char ash content increased. For anthracite, the increase of ash is mainly due to the addition of CaO.