Effect of Blending Ratio on the Sodium Release Behaviors, Ash Slagging Characteristics and Char Gasification Performances during Co-gasification of Zhundong Coal with Wuhai Coal
Effect of Blending Ratio on the Sodium Release Behaviors, Ash Slagging Characteristics and Char Gasification Performances during Co-gasification of Zhundong Coal with Wuhai Coal
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DOI：
10.1007/s11630-022-1737-z
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发表时间：
2022-12
影响因子：
2.5
通讯作者：
Shuaiyi Guo;Xiaofang Wang
中科院分区：
文献类型：
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作者：
Shuaiyi Guo;Xiaofang Wang
准东煤循环流化床气化（CFBG）过程中经常遇到炉底结渣、空气预热器表面结垢等灰源问题。低灰熔融温度（AFT）和强烈的钠释放应该是这些问题的原因。在工业上，配煤被认为是一种既能提高AFT又能控制钠释放的可行方法。本工作选用乌海煤作为配煤。该比率以10%的间隔从0质量%至40质量%变化。在实验室规模的炉中通过950°C的蒸汽气化混合样品。采用ICP-OES、AFT、XRD和TG等分析手段对不同反应条件下的钠析出行为、灰结渣特性和半焦气化性能进行了研究。结果表明，配煤可显著降低煤的钠释放行为。对于灰渣结渣特性，发现4个AFT（变形温度、软化温度、半球温度）中有3个与掺合比呈U型相关，表明掺合比越低，灰渣结渣问题越严重。这是由于形成了相当大比例的易熔含钠硅酸盐和铝硅酸盐。此外，配煤使ST-DT显著增大，说明抗床温波动能力显著增强。由于高水平的碱和碱性物质，在共气化期间清楚地观察到协同效应。综合考虑各项指标，推荐乌海煤掺烧比例为30%。
Some ash related problems, such as slagging at furnace bottom and fouling at the air pre-heater surface, are frequently encountered during circulating fluidized bed gasification (CFBG) of Zhundong coal. Low ash fusion temperatures (AFTs) and intense sodium release should be responsible for those problems. In industry, coal blending is deemed to be a feasible method to both improve AFTs and control sodium release. In this work, Wuhai coal was selected as blending coal. The ratio is varied from 0% to 40% by mass with 10% interval. The mixed samples were gasified by steam at 950°C in a lab-scale furnace. Some key indices, such as sodium release behaviors, ash slagging characteristics and char gasification performances, were investigated by ICP-OES, AFTs, XRD and TG analyzers, respectively. The results indicated that coal blending could significantly decrease sodium release behaviors. For ash slagging characteristics, it is surprised to find that three out of four AFTs (deformation temperature, softening temperature, hemispherical temperature) show an U-shaped correlation with blending ratio, indicating that a low ratio possibly causes more severe ash slagging problem. It is ascribed to the formation of substantial percentage of fusible Na-containing silicates and aluminosilicates. In addition, coal blending greatly increases ST-DT, implying that the ability of resistance to bed temperature fluctuation is markedly enhanced. Due to the high level of alkali and alkaline species, the synergistic effect is clearly observed during co-gasification. Taking all key indices into consideration, 30% blending ratio of Wuhai coal is recommended.