高岭土粒径对新疆煤积灰行为及烧结特性的影响

Effect of Kaolin Particle Size on Ash Deposition and Sintering Characteristics of Xinjiang Coal

针对燃烧新疆煤面临严重的沾污结渣问题,添加高岭土添加剂是缓解该问题的有效途径。结合沉降炉积灰实验和固定床烧结实验对不同粒径高岭土的防控性能与机理进行研究。结果表明:高岭土通过自身的稀释作用和与煤中矿物的交互作用两方面共同改变新疆煤的成灰特性,进而影响积灰行为与烧结特性;细高岭土虽然通过交互作用可以有效抑制碱性物质气相沉积,但添加剂自身的稀释作用导致成灰粒径较小,更易在初始阶段形成积灰;在两方面的综合作用下,细高岭土和粗高岭土对初始阶段积灰生长的防控效果相近;此外,添加细高岭土后更小的成灰粒径分布促进灰烧结程度的发展,不利于沉积物的吹灰清除。

Severe ash deposition and slagging issues have occurred during the combustion utilization of Xinjiang coal,and adding kaolin additives is an effective way to address these issues.With the sedimentation furnace ash accumulation experiments and the fixed-bed sintering experiments,the performances and mechanism for prevention and control of kaolin with different particle sizes were studied.Results show that kaolin changes the ash-forming characteristics of Xinjiang coal through its dilution and interaction with minerals in coal,which in turn affects the ash accumulation behaviors and sintering characteristics.Although fine kaolin can effectively inhibit the vapor deposition of alkaline substances through interaction,the dilution of the additives leads to a smaller ash particle size.Therefore,it is easier to form ash deposition in the initial stage.Under the combined effect of above two aspects,fine kaolin and coarse kaolin have similar prevention and control effects on the growth of ash accumulation in the initial stage.In addition,the smaller ash size distribution after the addition of fine kaolin promotes the development of ash sintering degree,which is not conducive to the soot blowing and removal of sediments.