Reducing steam transport pipe temperatures in power plants
Reducing steam transport pipe temperatures in power plants
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DOI：
10.1016/j.energy.2019.06.059
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发表时间：
2019-09
期刊：
影响因子：
9
通讯作者：
C. Wales;M. Tierney;M. Pavier;P. Flewitt
中科院分区：
文献类型：
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作者：
C. Wales;M. Tierney;M. Pavier;P. Flewitt
将循环分析应用于具有新型蒸汽管道的先进超超临界蒸汽装置模型。所建议的传输管道包括内部热涂层和外部护套以实现冷却。这可以实现更高温度的工作蒸汽，同时保持管壁温度低于更传统钢合金的可接受极限，避免使用成本更高的奥氏体不锈钢和镍基合金。基线设计的过热度为700°C，再热温度为720°C。2.8毫米的热涂层厚度足以使超临界锅炉后的换汽管壁温保持在600℃以下。对于位于再热器后的传递管，需要较厚的涂层或较小的再热温度以达到可接受的管壁温度。而亚临界电厂的计算循环效率为42.1%，在常规的超超临界蒸汽中，温度和压力升高将循环效率提高到52.2%。采用热障对设计进行修改，循环效率降至51.4%，仍明显优于亚临界电厂。替代的工厂冷却安排可能会提高管道温度，但对整体循环效率的影响微乎其微。
A cycle analysis has been applied to a model of a advanced ultra-supercritical steam plant with novel steam pipes. The transfer pipes proposed incorporate internal thermal coatings and are externally jacketed to enable cooling. This enables higher temperature working steam, while keeping the pipe wall temperature below the acceptable limit for more conventional steel alloys and avoiding the need to use higher cost austenitic stainless steels and nickel base alloys. The baseline design had a superheat temperature of 700 C∘ and a reheat temperature of 720 C∘. A thermal coating thickness of 2.8 mm is sufficient to keep the wall temperatures of the steam transfer pipe after the supercritical boiler below 600 C∘. For the transfer pipe located after the reheater a thicker coating or less ambitious reheat temperature is required to achieve acceptable pipe wall temperatures. Whereas subcritical plant has a calculated cycle efficiency of 42.1%, the elevated temperature and pressure in a customary ultra-supercritical steam boost cycle efficiency to 52.2%. Modifying this design with a thermal barrier lowers the cycle efficiency to 51.4%, still appreciably better than for subcritical plant. Alternative plant cooling arrangements might improve pipe temperatures but have minimal impact on overall cycle efficiency.