Abstract In this paper, experiments were carried out to obtain the actual operation characteristics of external heat exchangers (EHEs) in the first 600 MW supercritical CFB boiler. The furnace temperatures and some operational parameters in EHEs were measured and the heat transfer coefficients of heating surfaces in EHEs were calculated. The results showed that by controlling the solid flow rates to the EHEs, the furnace temperature were adjusted for good performance at various boiler loads and the bed temperature were maintained stable at full load. The heat transfer coefficients in EHEs were mostly over 200 W/(m2 ∙ K), which contributed to the flexible temperature regulation. The tube panel wall temperatures were found to be a saddle-shaped distribution, which was high in the bed center but low near the wall. Packet renewal theory was used to explain such uneven temperature distribution. These results confirm the importance of EHEs to the furnace temperature control of the supercritical CFB boilers, but the uneven tube wall temperatures need to be well solved in the future.

中文翻译：

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600MW超临界CFB锅炉外置换热器运行特性

摘要 本文通过实验获得了首台600 MW超临界循环流化床锅炉外换热器（EHE）的实际运行特性。测量了 EHE 中的炉温和一些操作参数，并计算了 EHE 中受热面的传热系数。结果表明，通过控制进入 EHE 的固体流量，可以调节炉温以在各种锅炉负荷下获得良好的性能，并且床温在满负荷时保持稳定。EHE 中的传热系数大多超过 200 W/(m2 ∙ K)，这有助于灵活的温度调节。发现管板壁温呈马鞍形分布，在床层中心高，靠近壁面温度低。数据包更新理论被用来解释这种不均匀的温度分布。这些结果证实了 EHEs 对超临界 CFB 锅炉炉温控制的重要性，但未来需要很好地解决管壁温度不均匀问题。