快速热处理石油焦与煤的微观结构变化及气化活性分析

为了研究在接近工业气化条件下石油焦和煤的结构和气化活性变化规律的差异,在滴管炉装置内,800~1 400℃对两种石油焦和一种烟煤进行快速热处理。用比表面积孔隙分析仪、XRD分析仪考察快速热处理对石油焦和煤的孔隙结构、碳微晶结构的影响,用热重分析仪考察不同温度快速热处理后石油焦和煤的CO₂气化活性。结果表明,石油焦与煤相比,孔隙结构主要由微孔组成,随快速热处理温度的升高,石油焦和煤微孔比表面积和孔容均先增大后逐渐减小;快速热处理降低了石油焦和煤的石墨化程度,石油焦碳微晶结构变化主要表现在堆垛高度的变化,而煤的碳微晶结构变化在衍射峰对应的2θ₀₀₂值、晶面间距和堆垛高度上均有体现;石油焦和煤的气化活性随快速热处理温度升高的变化趋势不同,但均与碳微晶结构参数(石墨化程度)的变化紧密相关。

Changes in the microstructure and gasification reactivity of petroleum coke and coal samples after rapid pyrolysis

To investigate the changes in the structure of petroleum coke and coal after rapid pyrolysis under the condition similar to the practical coal gasifier, two kinds of petroleum cokes and one bituminous coal were pyrolyzed in a drop tube furnace at 800~1 400℃. The structure of petroleum coke and coal were characterized by using surface area porosity analyzer and XRD (X-ray diffraction) analyzer, the CO₂ gasification reactivity of samples was examined by TGA (thermogravimetric analyzer). The result shows that the pore in petroleum coke is mainly micropore compared with coal; with the increase of pyrolysis temperature, the micropore surface area of petroleum coke and coal increases first and then decreases gradually. Rapid pyrolysis lowers the graphitization degree of petroleum coke and coal. The changes in the carbon crystallite structure for petroleum coke are mainly observed in the average stacking height, while the changes in the carbon crystallite structure for coal is manifested in the value of 2θ₀₀₂, interlayer spacing and average stacking height. Although the gasification reactivity changing tendency of petroleum coke and coal with the increase of pyrolysis temperature is different, the gasification reactivity is closely related to the carbon crystallite structure.