摘要
为了向固定床热解烟煤制备高值燃料的工业放大提供基础数据,采用热重分析仪(TG)和热重质谱联用分析仪(TG-MS)对比研究了N_2、CH_4、CO_2、H_2以及CO_2+CH_4混合气氛下陕西榆林烟煤热解特性及动力学参数变化规律。在此基础上,采用TG-MS研究了不同热解气氛下气体产物的释放规律。实验结果表明:煤样的热解大致可分为三个阶段,第一阶段温度区间为室温~388℃;第二阶段为388~605℃,第三阶段为605~1000℃。N_2、CO_2+CH_4混合气氛下达到最大释放强度在505℃左右,而在H_2、CH_4和CO_2气氛下CH_4最大析出强度峰向高温段推移,且CO_2气氛下CH_4最大析出温度推移最多。由于在CO_2气氛下煤样与CO_2发生气化反应过程中涉及的反应较多,因此热解反应第二阶段和第三阶段,采用二级反应(n=2)和三级反应(n=3)可以更好的描述煤的热解过程。
In order to provide basic data for industrial scale-up of high value fuel prepared from pyrolysis bituminous coal in fixed bed reactor,the pyrolysis characteristics and kinetic parameters of bituminous coal from Shaanxi Hongliulin in N_2,CH_4,CO_2,H_2 and CO_2+CH_4 mixture were studied in a thermogravimetric analyzer( TG) and thermogravimetric mass spectrometry analyzer( TG-MS). On this basis,thermogravimetric mass spectrometry analyzer( TG-MS) were used to investigate the release of gaseous products. The experimental results showed that the pyrolysis of coal sample can be divided into three stages. The first stage is temperature range from room temperature to 388℃; the second stage is 388 ~ 605℃; the third stage is 605 ~ 1000℃.The maximum release intensity in N_2 and CO_2+CH_4 appeared at about 505℃. In carrier gas of H_2,CH_4 and CO_2,the maximum release peak of CH_4 passes to the high temperature,and the maximum release temperature of CH_4 increases most in CO_2. The reaction between coal sample and CO_2 during gasification is more involved. Therefore,the pyrolysis process of coal can be described better by second-order reaction( n = 2) and three-order reaction( n = 3) in the second and third stages of pyrolysis reaction.
引文
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