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水分对无烟煤破碎行为和研磨能耗的影响

Effect of moisture on anthracite crushing behavior and grinding energy consumption

  • 摘要: 煤中水分赋存形态和含量的变化会改变煤炭物理特性和孔隙结构,进而影响其破碎过程。为研究煤炭所含水分对其破碎行为的影响,以无烟煤为研究对象,利用加装功率测量装置的哈氏可磨仪模拟中速磨煤机内的破碎环境,对不同含水量煤样开展多时间批次的单独与混合破碎试验,并研究水分对煤炭破碎速率、煤粉细度及研磨能耗的影响。试验结果表明:相比于原始煤样,均化浸泡煤样单独破碎时初始粒级物料破碎速率因含水量的增加明显减小,其可磨性指数随水分增加先减小后增大,煤粉细度t10与含水量呈正相关关系。干、湿煤样混合破碎时13.34%含水量样品破碎速率和细粒级物料生成速率远大于相同水分的均化浸泡煤样,且其可磨性指数大于原煤;其他含水量的混配煤样可磨性指数略小于均化浸泡煤样,此差异随含水量增加而变大,而破碎速率和细粒级物料产率与均化浸泡煤样差别较小。经典能量—粒度关系模型可用来表征不同水分梯度样品单独和混合破碎过程,内、外水分不同程度降低了无烟煤抵抗破碎的能力,单独破碎时含水量增加可显著提高能量效率;将含水量参数引入能耗模型,实现对多梯度水分煤样破碎过程的表征。通过探究煤中含水量对煤炭破碎能耗的影响机理,揭示煤炭破碎过程中能量损失方式并为优化煤炭破碎工艺、降低能耗提供理论指导。

     

    Abstract: The change of water occurrence form and content in coal will change the physical characteristics and pore structure of coal, and then affect its crushing process.In order to study the effect of moisture contained in coal on on the crushing behavior of coal particles,anthracite coal was used as the research object. A Hastelloy grinding equipped with a power measuring device was applied to simulate the crushing environment in a medium-speed coal mill. The individual and mixed crushing experiments were carried out in multi-time batches of coal samples with different water content. Thus, the effects of water occurrence on coal crushing rate, pulverized coal fineness, and grinding energy consumption were studied. The experimental results showed that compared with the original coal samples, the initial particle size material crushing rate of homogenized soaked coal samples decreases significantly due to the increase of water content, its grindability index first decreased and then increased with increasing the water content when the homogenized immersed coal sample was crushed separately, and the fineness of pulverized coal t10 was positively correlated with water content. When dry and wet coal samples were mixed and crushed, the crushing rate and fine-grained material generation rate of 13.34% moisture content samples were much higher than that of homogenized soaked coal samples with the same moisture content, and their its grindability index was larger than that of the original coal; The grindability index of the blended coal samples with other moisture contents was slightly smaller than that of the homogenized soaked coal samples, and this difference became larger with the increase of moisture content, while the crushing rate and the yield of fine-grained materials differed less from that of the homogenized impregnated coal samples. Also, the result indicated that the classical energy-particle size relationship model may be used to characterize the individual and mixed crushing processes of samples with different moisture gradients. The internal and external moisture reduced the ability of anthracite to resist crushing to varying degrees, and increasing the water content during separate crushing improved the energy efficiency significantly. So, the water content parameters were introduced into the energy consumption model to characterize the crushing process of various moisture coal samples. By exploring the influence mechanism of water content in coal on energy consumption of coal crushing, it reveals the way of energy loss in the process of coal crushing and provides theoretical guidance for optimizing coal crushing process and reducing energy consumption.

     

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