低阶烟煤密实炼焦中显微组分的交互作用规律研究

Due to the shortage of high quality coking coal source, low-rank bituminous coals were gradually used in coke-making by blending coals. But, the problems that are different from the existing theory for blending are often met, which is difficult to explain at present. In this project, the emphases are focused on the coking differences of the macerals in the low-rank bituminous coal and the mechanism of these macerals in the coking process, and its effect on the coke quality. First, the inherent reason for the difference of the macerals in low-rank bituminous coal during the carbonization process is to be explained based on the separation of coal petrography and the pyrolysis behavior of the macerals combining the structure analysis of low-rank coal. We are going to find the tunable mechanism of the macerals by analyzing the softing and fusion characteristics of the maceral to construct the coking index of low-rank bituminous coal and find the relationships between the quality of coal, coal petrography, the pyrolysis characteristic parameters and the viscosity of plastic mass, swell and conductivity. By studying the characteristics of plasticity plastic mass and semi-coke in carbonization process combining the reflection, optical texture of coke and the same coke strength of reaction of the blended coals in the blending coal of low-rank bituminous coal and caking coal, the interaction mechanism of the maceral in the blended coals during the tamping coking process and its effect on the quality of coke will be revealed. The obtained results will provide the important theory support for the coke-making technology by tamping and moulded coal tamping coking.

随着我国优质炼焦煤资源短缺，低阶烟煤逐渐用于炼焦配煤，但实际生产中常出现与现有配煤理论相悖和难以解释的问题。本项目重点研究低阶烟煤显微组分干馏成焦粘结性的差异性、不同变质程度煤岩显微组分干馏过程相互作用机制及其对焦炭质量的影响规律。首先，从低阶烟煤结构特性入手，结合煤岩分离研究煤及其显微组分的热解行为，阐明低阶烟煤显微组分干馏粘结性差异的内在原因。在密实炼焦条件下，通过对低阶烟煤及其显微组分干馏过程中软化熔融特性的研究，构造表征低阶烟煤干馏粘结差异性指标，并将煤质和煤岩、热解特征参数与胶质体粘度、膨胀与导电等特性关联，揭示其粘结性调控机理。通过低阶烟煤与炼焦煤二元配煤，研究干馏过程的塑性胶质体及半焦特征，并结合焦炭光学组织、反射率及等反应后强度的变化特性，揭示配煤中不同煤岩显微组分在密实炼焦过程中相互作用机制及其对焦炭质量的影响。研究成果将为捣固、配型煤等密实炼焦生产提供重要的理论支撑。

随着我国优质炼焦煤资源短缺，低阶烟煤逐渐用于炼焦配煤，但实际生产中常出现与现有配煤理论相悖和难以解释的问题。本项目通过低阶煤组成与结构、低阶煤热解特征、低阶煤的降粘特性、高堆密度下热解与成焦特性以及低阶煤共碳化等五个部分，重点研究低阶烟煤显微组分干馏成焦粘结性的差异性、不同变质程度煤岩显微组分干馏过程相互作用机制及其对焦炭质量的影响规律。研究结果表明：低阶煤基本结构单元较小，统计约1.8~2.8个芳香环，但芳碳率均高于气煤统计值，同时低阶煤的不饱和度参数又较高，与常规炼焦煤结构特征与粘结性的关系有明显差异；低阶煤显微组分如镜质组、丝质组与炼焦煤配合时，其成焦行为与常规炼焦煤对应显微组分的作用并不一致，低阶煤丝质组对黏结性指标的裂化程度反倒比镜质组要小，以及低阶煤显微组分与不同煤种的交互作用程度各异等；当堆密度从顶装焦炉散装时约0.75 t/m3到捣固炼焦的最高密度1.2 t/m3时，随堆密度增加，热解开始温度、剧烈热解温度总体向后移动，同一温度下较散装煤的失重率小。不同比例的低阶煤与气煤、焦煤和肥煤混煤热解时，差异主要在于失重特征参数，但并不是单种煤的简单叠加，存在交互作用；通过70kg焦炉试验，当配煤结构不变或适当调整煤种结构，在保证焦炭质量的条件下，直接配入低阶煤的数量不应超过3%的比例，使用预处理脱除部分挥发分的煤，使用量可在增加1-2%，通过成型或密实（捣固）炼焦，优化条件下可达10%。研究成果将为捣固、配型煤等密实炼焦生产提供重要的理论支撑。