氧化钙在煤岩显微组分气化中的作用研究

The Effect of CaO on CO_2-or H_2O (g)-Gasification of Coal Macerals

用装有气相色谱在线分析的高温高压差热分析装置在773～1273K的温度范围内考察了氧化钙对平朔烟煤三种基本有机显微组分(镜质组、稳定组和丝质组)分别与CO_2和水蒸气进行气化反应的影响。CO_2的反应压力和水蒸气的反应分压分别为1.0MPa和10KPa,升温速率均为10K/min.反应性测定和气化动力学数据处理结果发现,CaO对显微组分的气化有催化作用,而且这种作用在CO_2气化中更明显;显微组分的类型和气化反应气氛决定CaO的最佳添加量。对试样气化后残渣的电子探针能谱测定表明,CaO在显微组分的气化过程中具有固硫能力,这种能力从强到弱的顺序为稳定组、镜质组和丝质组,而且在水蒸气气化中的固硫作用更显著。扫描电镜对残渣的观察表明,CaO对显微组分在气化中的灰团聚具有阻抑作用,其机理与对显微组分气化的催化作用机理相似。用于煤/煤焦加压气化的动力学模型可以用来描述显微组分的气化和催化气化过程。

The effect of calcium oxide on carbon dioxide or steam gasification of the three individual macerals , vitrinite, liptinite and fusinite, separated from Pingshuo bituminuos coal is investigated using the system of a differential thermal analyzer combining with a gas chromato-graph (DTA-GC) in a temperature range of 773-1273K and a CO2 pressure of 1. 0 MPa or a partial steam pressure of 10 kPa at a heating rate of 10 K/min. The result of both reactivity measurement and kinetic data processings show that the catalytic effect of CaO is more obvious on CO2-gasification of vitrinite and liptinite than on H2O (g) -gasification of these two macerals. The catalytic effect of CaO is related to both specific surface area and chemical structure of the macer-als and the CaO-additive amount. The analysis of the maceral residues with or without CaO addition after gasification by an electron probe energy spectrometer show that CaO has more obvious sulfur capture behaviour in steam gasification than that in CO2 gasificaton and the order of capture ability of CaO in maceral gasification is as liptinite>vitririitel>fusinite. The observation of the residues by a scanning electron microscope show that the maceral residues without CaO additive after gasification reaction tended towards agglomeration even though reaction temperature was much lower than its softenpoint, and this tendency could be inhibited when CaO was added in the macerals . This inhibition mechanism is similar to the catalytic mechanism of CaO in the maceral gasification.