准东煤中钠元素赋存形态及洗煤对气化特性的影响

Modes of occurrence of sodium in Zhundong coal and effect of coal-washing on gasification

为探究准东煤中钠元素赋存形态及洗煤对准东煤气化特性的影响,采用逐级洗煤法对准东煤进行洗煤处理。利用电感耦合等离子体质谱仪、离子色谱仪和X射线衍射仪研究了准东煤中钠元素赋存形态及含量。利用热重分析仪研究了煤样的气化特性,并采用等转化率法计算气化反应动力学参数。结果表明:准东煤中钠元素主要以水溶钠为主,但并非以钠盐化合物晶体的形式存在于煤中。洗煤对煤样孔结构特性和矿物质含量均产生影响,矿物质含量较低时,气化特性主要由煤样的孔结构特性决定。随着洗煤程度加深,煤焦碳转化率达到90%时所需的时间由5.35延长至12.02 min,气化反应活性指数逐渐降低,气化反应活化能由177.7～214.8增大至203.5～252.4 kJ/mol。

In order to investigate the modes of occurrence of sodium in Zhundong coal and effects of coal-washing on gasification, the sequential coal-washing method was used to wash Zhundong coal. The modes of occurrence and content of sodium in Zhundong coal were studied by inductively coupled plasma mass spectrometry, ion chromatograph and X-ray diffraction. The gasification of coal samples were studied by thermo gravimetric analyzer, and the kinetic parameters of gasification reaction were analyzed and calculated by iso-conversional method. The results suggest that the most of sodium in Zhundong coal is the water-soluble sodium, and not in the form of crystals of sodium salts in coal. Coal-washing can affect the pore structure characteristics and mineral content of coal. When the mineral content is low in coal, the gasification reactivity is mainly determined by the pore structure. With the deepening of coal-washing degree, the gasification time of carbon conversion rate reaching 90% extends from 5.35 to 12.02 min, the activity index of gasification decreases gradually, and the activation energy of gasification increases from 177.7-214.8 kJ/mol to 203.5-252.4 kJ/mol.