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-  2019 

/循环流化床锅炉燃烧调整试验 /

Keywords: 循环流化床锅炉,燃烧调整,含碳量,煤粒度,布风板,灰渣 CFB boiler,combustion adjustment,carbon content,coal particle size,grid,ash and slag

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Abstract:

针对国内A电厂410 t/h循环流化床(CFB)锅炉灰渣含碳量偏高、运行稳定性较差等问题,对锅炉一次风量、返料风量、入炉煤粒度等主要运行参数进行优化调整,探索锅炉最佳运行参数组合。结果表明:入炉煤粒度偏细,中位径仅约为1 037.97μm,锅炉底渣中位径仅为375.64μm,表明入炉煤的成灰特性较好;炉膛上部灰浓度差压值高达约2.5 kPa,表明炉内细颗粒组分偏多,循环灰量受到一次风量的影响波动较大。为保证锅炉返料的稳定运行,控制穿过布风板的一次风量仅约为102 300 m3/h,远低于设计值183 000 m3/h,较同类型机组严重偏低。过低的一次流化风量使密相区燃烧缺氧严重,是引起灰渣含碳量偏高的主要原因。此外过低的一次风量,致使布风板阻力仅为2.1 kPa。与同类型锅炉布风板的阻力相比,布风板阻力偏小,造成锅炉局部流化不良、温度分布不均匀等。建议合理调节入炉煤粒度,控制其中位径在2 000~3 000μm,优化炉内灰浓度分布,提高一次运行风量,可有效提高锅炉燃烧效率。 Aiming at the problems of high carbon content in ash and poor operation stability of 410 t/h circulating fluidized bed (CFB) boilers in A power plant,the main operation parameters such as primary air volume,return air volume and coal particle size were optimized and adjusted,and the optimum combination of boiler operation parameters was explored.. The test results show that the size of the coal entering the furnace is slightly fine and the median diameter is only about 1 037.97 μm. The median diameter of the boiler bottom slag is only 375.64 μm,which indicates that the ash-forming characteristics of the coal entering the furnace are better. The running picture shows that the differential pressure value of ash concentration in the upper part of the furnace is as high as about 2.5 kPa. The excessive fine ash particles in the furnace make the circulating ash volume fluctuate greatly under the influence of primary air volume. In order to ensure the stable operation of the return material of the boiler,the primary air flow through the air distribution plate controlled by the operator is only 102 300 m3/h,which is much lower than the design value of 183 000 m3/h,and is also seriously lower than that of the same type of units. The results show that the main reason for the high carbon content of ash slag is that the low primary fluidized air volume makes the combustion in dense phase zone seriously anoxic. In addition,the low primary air flow makes the resistance of the distributor only 2.1 kPa. Compared with the resistance of the air distributor of the same type of boiler,the resistance of the air distributor is smaller,which results in poor local fluidization and uneven temperature distribution of the boiler. It is suggested that the combustion efficiency of the boiler can be effectively improved by adjusting the size of coal into the furnace reasonably,controlling the median diameter between 2 000-3 000 μm,optimizing the ash concentration distribution in the furnace and increasing the primary air flow

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