低温氧化条件下煤质特性变化的研究

Study on the change of coal quality characteristics under the condition of low temperature oxidation

为了探究煤质特征变化的原因和煤分子结构变化的规律,通过测定煤样的水分、发热量、挥发分、粘结指数的变化,采用差热扫描分析仪、傅里叶变换红外光谱、扫描电镜等手段,验证了低温氧化条件下煤样煤质特征的变化情况,表明了低温氧化煤质特征的变化机理。实验结果表明:随着低温氧化时间的不同,褐煤和长烟煤的水分含量发生明显的降低,而中等变质程度以上的烟煤,水分含量受低温氧化的影响较弱;随着煤变质程度的升高,低温氧化对其发热量的影响逐渐减小;低温氧化使煤样的挥发分和粘结性呈现下降的趋势,且随着煤变质程度的增高,氧化对挥发分的影响逐渐减小,而气煤和焦煤的粘结性下降较明显。

In order to explore the reasons for the change of coal quality characteristics and the law of the change of coal molecular structure,in this paper,the changes of moisture,calorific value,volatile matter and caking index of coal samples were measured,and the change of coal quality characteristics is verified under the condition of low-temperature oxidation by means of differential thermal scanning analyzer,Fourier transform infrared spectrum and scanning electron microscope.And the characteristics of low-temperature oxidized coal the change mechanism of the sign are shown.The experimental results show that the moisture content of lignite and long bituminous coal decreases obviously with the different oxidation time,while the moisture content of bituminous coal with medium degree of metamorphism is less affected by low-temperature oxidation.With the increase of coal metamorphism,the influence of low-temperature oxidation on its calorific value decreases gradually.Low-temperature oxidation makes the volatile matter and cohesiveness of coal sample decrease.With the increase of coal metamorphism degree,the effect of oxidation on volatile matter decreases gradually,while the cohesiveness of gas coal and coking coal decreases obviously.