Guo Yang, Zhou Lu, Guo Fanhui, Chen Xiaokai, Wu Jianjun, Zhang Yixin
School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, P.R. China.
National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, P.R. China.
ACS Omega. 2020 Aug 26;5(35):22226-22237. doi: 10.1021/acsomega.0c02399. eCollection 2020 Sep 8.
An accurate and quantitative description of the pore structure of gasification-coke using fractal geometry could be of great significance to its industrial utilization. In this study, gasification-coke was prepared with low-quality coal blending at different high-temperature residence times to investigate the variation in the pore structure, fractal dimensions, reactivities, and their relationship. The pore structure parameters (e.g., specific surface area, pore volume, and average pore diameter) of gasification-coke were investigated by low-temperature N adsorption/desorption and mercury intrusion porosimetry. Fractal dimensions and (at relative pressures of 0-0.5 and 0.5-1, respectively) were calculated using the fractal Frenkel-Halsey-Hill model, and the fractal dimension was obtained using the Menger sponge model. The results show that the pore structure systems of gasification-coke prepared at different high-temperature residence times are continuous and complete, which contributes to the gasification reaction. The variation trend of the macropore structure parameters is more complex than that of micropore and mesopore with the extension of the high-temperature residence time. It is found that is linearly correlated with the micropore specific surface area, indicating that is more suitable for reflecting the roughness of the micropore surface; is linearly correlated with the mesopore volume and can describe the volumetric roughness of the mesopore; and reflects the irregularities and surface roughness of the macropores. Gasification reactivity is closely related to the value, and the reactivity of the gasification-coke may be improved if the number of mesopores is increased by controlling the high-temperature residence time or other pyrolysis conditions. The research results will provide theoretical reference for controlling the gasification reaction of gasification-coke and gasifier design.
用分形几何对气化焦的孔隙结构进行准确且定量的描述，对其工业利用具有重要意义。本研究采用低质煤配煤在不同高温停留时间下制备气化焦，以研究孔隙结构、分形维数、反应活性的变化及其关系。通过低温氮吸附/脱附和压汞法研究了气化焦的孔隙结构参数（如比表面积、孔隙体积和平均孔径）。分别使用分形弗伦克尔-哈西-希尔模型计算了相对压力为0 - 0.5和0.5 - 1时的分形维数 和 ，并使用门格海绵模型获得分形维数 。结果表明，不同高温停留时间制备的气化焦的孔隙结构系统连续且完整，有利于气化反应。随着高温停留时间的延长，大孔结构参数的变化趋势比微孔和中孔更为复杂。发现 与微孔比表面积呈线性相关，表明 更适合反映微孔表面的粗糙度； 与中孔体积呈线性相关，可描述中孔的体积粗糙度； 反映了大孔的不规则性和表面粗糙度。气化反应活性与 值密切相关，通过控制高温停留时间或其他热解条件增加中孔数量，可能提高气化焦的反应活性。研究结果将为控制气化焦的气化反应及气化炉设计提供理论参考。
