低灰熔点煤的熔融特性研究分析OA

During the combustion of low ash-fusion-temperature coal,severe melting phenomena occur,leading to the fouling of heat exchange surfaces.Long-term operation can result in serious slagging.Therefore,studying the melting characteristics of low ash-fusion-temperature coal is of significant importance.Three different low ash-fusion-temperature coals with varying ash contents were analyzed,along with a high ash-fusion-temperature coal.The slagging indices were calculated based on the ash composition and fitted with the ash fusion temperature.Coal ash was prepared at different temperatures,and the variations in the content of alkali/alkaline earth metals in the ash were investigated,along with their influence on the prediction of slagging characteristics.The study found that the content of calcium and iron metals in low ash-fusion-temperature coals was much higher than in high ash-fusion-temperature coal.The acid-base ratio(B/A),silica ratio(G),silica-alumina ratio,iron-calcium ratio,and a comprehensive index all showed a certain relationship with the ash soft temperature.However,the comprehensive index and the silica-alumina ratio had a better linear relationship with the ash soft temperature.High-temperature viscosity experiments showed that when the flue gas temperature decreased to the ash flow temperature,the viscosity of the ash increased rapidly,leading to its adhesion to heat exchange surfaces.As the coal ash preparation temperature increased,the sodium content in the ash decreased rapidly,while the relative content of iron and calcium showed an increasing trend.The magnesium content first increased and then decreased.