不同变质程度煤的吸附瓦斯动力学特性实验研究

    Experimental study on kinetic characteristics of gas adsorption of coal with different degrees of metamorphism

    • 摘要: 为了进一步揭示不同变质程度的煤在不同吸附压力下的动力学特征,利用自主研发的TQY-2型精密吸附仪和红外热成像装置对直径为8.5 mm的褐煤、焦煤和无烟煤煤样进行不同压力(0.2、0.4、0.6、0.8、1.0 MPa)下的宏观吸附试验和吸附压力为(0.3、0.6、0.9、1.2、1.5 MPa)的煤体细观结构吸附试验,利用准一级、准二级、颗粒内扩散、Elovich以及双常数等吸附动力学模型分析吸附瓦斯规律及机理。研究表明:对比5种吸附动力学模型,准二级吸附动力学模型适合表征褐煤和焦煤的吸附瓦斯过程,而无烟煤的最优模型为颗粒内扩散模型;随着吸附压力升高,褐煤和焦煤的准二级吸附速率常数k2逐渐增加,无烟煤的颗粒内扩散速率常数kp也逐渐增加,均呈正相关;吸附压力对煤样适合的动力学模型影响较小;在宏观吸附和基于红外热成像的煤体细观结构吸附实验下,煤样适合的动力学模型一致。

       

      Abstract: In order to further reveal the dynamic characteristics of coal with different degrees of metamorphism under different adsorption pressures, the self-developed TQY-2 precision adsorption instrument and infrared thermal imaging device were used to conduct macroscopic adsorption tests on lignite, coking coal and anthracite coal samples with a diameter of 8.5 mm at different pressures (0.2, 0.4, 0.6, 0.8, 1.0 MPa) and the adsorption test of the mesoscopic structure of the coal body with adsorption pressures of (0.3, 0.6, 0.9, 1.2, 1.5 MPa), using quasi-primary and quasi-secondary adsorption kinetic models such as intra-particle diffusion, Elovich and double constant analyze the law and mechanism of adsorption gas. The results show that compared with five adsorption kinetics models, the quasi-secondary adsorption kinetics model is suitable for characterizing the adsorption gas process of lignite and coking coal, while the optimal model for anthracite is the intra-particle diffusion model; with the increase of adsorption pressure, the quasi-secondary adsorption rate constant k2 of lignite and coking coal gradually increased, and the intra-particle diffusion rate constant kp of anthracite coal also gradually increased, all of which were positively correlated; adsorption pressure has little effect on the dynamic model suitable for coal samples; under the macroscopic adsorption experiment and the mesoscopic structure adsorption experiment of coal body based on infrared thermography, the dynamic models suitable for different degrees of metamorphism are consistent.

       

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