基于系统分类的配煤灰熔融特性研究

Research on the Ash Fusion Characteristic of Blending Coal Based on Systematic Classification

根据不同熔融性和不同的矿物质组成对14种煤进行系统归类,利用硅酸盐相图理论解释混煤结渣的原因。并根据矿物组成,寻找不同类别煤种之间配煤的熔融性规律,探讨了选择合适煤种配煤使混煤灰熔点提高的配煤方法。同时,还设计了一种判别配煤效果的方法:T-φ法(T表示混煤灰熔点的软化温度,φ表示混煤熔点与低熔点煤之间的温度差,根据这2个指标,确定混煤灰熔点在坐标轴中的位置,判断配煤效果的好坏)。文中以灰熔点作为判断煤灰结渣倾向的标准。实验结果表明:由于配煤使灰中的成分更复杂,低温共熔现象更易发生,因而配煤总体是一个降低灰熔点的过程;但是将煤种分类,不同类别之间合理掺配能改善这种状况。富含勃姆石的高熔点的煤种参与配煤,能确保使混煤灰熔点一定高于低熔点煤;其他类型的高熔点煤,参与配煤后混煤灰熔性各异,并大体呈降低的趋势;中等熔点煤和低熔点煤混煤熔点一致呈现出低于2种单煤的规律;2种低熔点煤混合不能得到高熔点混煤的结果。

This paper focused on research which systematically classified 14 raw coals from different geological areas of China in accordance with ash constituents, and explained the reasons why the blended coals are slagging with the help of phase diagrams of ceramics. According to mineral composition of raw coal, we proposed the theory of melting characteristic of blended coals and discussed the approaches of making the ash fusion temperature （AFT） of blended coals higher by selecting suitable raw coals. Meanwhile, we created a judgment to characterize the effects of coal blending： T-φ diagrams （y-axis T represents softening temperature of AFT, x-axis φ represents the temperature difference between the blended coal and low AFT coal and according to these two parameters, we can judge blending effect from the place where the blended coal sited in the diagram）. This paper regarded AFT as a criterion to estimate slagging propensities. Results show that： as coal blending leads to the result that the ingredients of ash are much more complex and low- temperature eutectic will easily occur, thus coal blending is generally a process for decreasing AFT or aggravating slagging. However, we find that classification of raw coal and scientific blending with raw coal of different categories can weaken slagging propensity. Coal-blending associated with the high-AFT raw coals which is rich in boehmite will ensure AFT rise; but there are no such cases when coals are blended with other high-AFT raw coals; the AFT of blended coals mixed with medium-AFT and low-AFT raw coals is decreasing consistently; coals blended with two low-AFT coals never make AFT higher.