燃用约旦油页岩循环流化床锅炉结渣沾污分析

Analysis on slagging and fouling of circulating fluidized bed boiler burning Jordan oil shale

约旦Attarat电站277 MW机组是世界上容量最大的纯燃油页岩循环流化床机组,为探究其运行过程中床层结渣、受热面积灰原因,通过试验明确床层结渣原因,并通过Factsage计算进一步验证;根据现场实际情况,分析了受热面积灰原因。结果表明:油页岩入炉粒度偏大或布风板流化不良,导致局部温度过高引起床层结渣,局部最高温度可达1150℃,此时液相质量占整个体系质量22%。此外,油页岩灰分高,锅炉飞灰在流经尾部对流受热面时,在热泳和惯性碰撞的共同作用导致受热面积灰严重。通过改善油页岩入炉粒径、更换合理结构的布风板、及时调整一次风量等措施可有效缓减结渣问题。通过更换效率更高的吹灰器、使用除灰剂等手段可有效解决锅炉受热面沾污问题。

The 277 MW unit of Jordan Attarat Power Station is a circulating fluidized bed unit with the largest capacity of pure fuel shale in the world.In order to explore the causes of bed slagging and ash accumulation on the heating surface during its operation,the causes of bed slagging were clarified through experiments,and were further verified by Factsage calculation.At the same time,the reason of ash accumulation on heating surface was analyzed according to the actual situation.The results show that the large size of oil shale in the furnace or the poor fluidization of the air distribution plate leads to high local temperature and slagging of the bed.The local maximum temperature can reach 1150℃,and the liquid mass accounts for 22%of the whole system mass.In addition,the ash content of oil shale is high.When the boiler fly ash flows through the convection heating surface at the tail,the joint action of thermal swimming and inertial collision leads to serious ash accumulation on the heating surface.Slagging can be effectively reduced by improving the grain size of oil shale,replacing the air distribution plate with reasonable structure and adjusting the primary air volume.The fouling problem of boiler heating surface can be effectively solved by changing the soot blower with higher efficiency and using ash remover.