Abstract

The coke quality depends on the characteristics of coal blend, pre-carbonization techniques adopted such as stamping, vibro-compaction etc., and coking conditions. Out of these properties, coal blend is an important role in the production of quality coke. Also, the quality of the blend depends on the quality of individual coals and their interaction during carbonization. The coals are in contact with air for periods of time during transportation and stockpiling, which sometimes may exceed several months. In these periods, reaction of coals with oxygen in the presence of water, sunlight and possibly raised the temperatures. The resulting weathered coal suffers some alteration in its technological properties, which in turn affects coke quality for blast furnace operation adversely. In this work, two coals belong to prime hard coking categories, namely Coal A and Coal B, were selected and kept in a separate stock pile for a period of 120 days. These coals were characterized in terms of proximate, rheological and petrography properties at a regular frequency. This paper summarizes the impact of weathering on the coking behavior of these two coals in terms of properties as mentioned above. However, the rate of loss depends on coal rank and storage conditions. Deterioration of rheological and petrographic properties were seen higher for Coal B compared to Coal A. Low-rank coal deteriorates at a faster rate because low-rank coal is dominated by free radicals that easily react with oxygen, resulting in the creation of various carbonyl groups and weathered vitrinite. Based on the results obtained in this study, size of stock piles for different coals to be maintained, at a specific time, can be determined and recommended, so that target coke quality is always achieved.

中文翻译：

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焦煤堆放过程中的风化

摘要

焦炭的质量取决于配煤的特性、采用的冲压、振动压实等预炭化技术以及焦化条件。在这些特性中，混煤在生产优质焦炭中起着重要作用。此外，混合物的质量取决于单个煤的质量及其在碳化过程中的相互作用。煤在运输和储存过程中与空气接触一段时间，有时可能超过几个月。在这些时期，煤与氧气在水、阳光的存在下发生反应，并可能升高温度。由此产生的风化煤的技术性能发生了一些变化，进而对高炉操作的焦炭质量产生不利影响。在这项工作中，两种煤属于优质硬焦类别，即煤 A 和煤 B，被选择并存放在单独的库存堆中 120 天。这些煤的特征是在规则频率下的近似、流变学和岩相学特性。本文从上述性质方面总结了风化对这两种煤的结焦行为的影响。然而，损失率取决于煤等级和储存条件。与煤 A 相比，煤 B 的流变学和岩相学特性恶化程度更高。低阶煤的劣化速度更快，因为低阶煤的主要成分是容易与氧反应的自由基，导致产生各种羰基和风化的镜质体。根据本研究中获得的结果，在特定时间，要维护的不同煤炭的储料堆大小，