Abstract—

The article addresses factors causing damage—in particular, flow accelerated corrosion wear (FAC) of tube walls—to the evaporator operating in the low-pressure loop of the Ep-258/310/35-15.0/3.14/0.44-540/535/263 (P-132) heat-recovery steam generator used as part of a 795-MW combined-cycle plant. Factors influencing the FAC, namely, improper water chemistry, availability of gas shunts in the steam generator, and high mixture motion velocity in the tubes in combination with the flow path configuration, are described. The damages inflicted to the tubes and their locations in the heat-recovery steam generator low-pressure loop are described. It is shown that gas shunts in the heat-recovery steam generator result in an increased heat absorption and higher velocity of medium in the boundary tubes of low-pressure evaporator tube banks, which intensifies the tube’s wear process. It has been found that the water chemistry used for the Kirishi District Power Plant (DPP) heat-recovery steam generator was not the factor that caused damage to the low-pressure loop tubes. The Kirishi DPP steam generator was compared with other similar large-capacity heat-recovery steam generators. For analyzing the low-pressure evaporator performance indicators, the loop and the processes occurring in it were modeled using the Boiler Designer software. An analysis of the results from comparison of the steam generator design and performance characteristics has shown that it is necessary to change the two-phase mixture motion velocity in the Kirishi DPP steam generator low-pressure loop by modifying the design or operating parameters. The wear of the low-pressure evaporator tube walls was mathematically modeled, the results of which confirm that erosion wear is one of the main factors causing damage to the tubes. The erosion is caused by the intense dynamic effect of two-phase, high-velocity flow jets on the tube walls. General recommendations for decreasing the wear of heat-recovery steam generator tubes are given. It has been determined that the increased wear of tubes in the low-pressure loop of the P-132 steam generator at the Kirishi DPP is caused by a combination of a few factors, such as high velocity of steam–water mixture, availability of bends, and unsatisfactory quality of aligning the tubes at their welding places.

中文翻译：

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大容量余热回收蒸汽发生器低压回路蒸发管损坏的因素研究

摘要—

该文章解决了对在Ep-258 / 310 / 35-15.0 / 3.14 / 0.44-540 / 535低压回路中运行的蒸发器造成损坏的因素，尤其是管壁的流动加速腐蚀磨损（FAC） / 263（P-132）热回收蒸汽发生器，作为795兆瓦联合循环电厂的一部分。描述了影响FAC的因素，即不正确的水化学性质，蒸汽发生器中分流器的可用性以及与流路配置相结合的管道中的高混合物运动速度。描述了在热回收蒸汽发生器低压回路中对管道造成的损坏及其位置。结果表明，热量回收蒸汽发生器中的气体分流导致低压蒸发器管束的边界管中的吸热增加和介质的流速更高，从而加剧了灯管的磨损过程。已经发现，用于Kirishi地区发电厂（DPP）热回收蒸汽发生器的水化学物质不是造成低压回路管损坏的因素。将Kirishi DPP蒸汽发生器与其他类似的大容量热回收蒸汽发生器进行了比较。为了分析低压蒸发器性能指标，使用Boiler Designer软件对回路和其中发生的过程进行了建模。对蒸汽发生器设计和性能特征进行比较的结果分析表明，有必要通过修改设计或运行参数来更改Kirishi DPP蒸汽发生器低压回路中的两相混合物运动速度。对低压蒸发器管壁的磨损进行了数学建模，其结果证实了腐蚀磨损是造成管子损坏的主要因素之一。腐蚀是由两相高速射流在管壁上的强烈动力作用引起的。给出了减少热量回收蒸汽发生器管磨损的一般建议。已经确定，在Kirishi DPP的P-132蒸汽发生器低压回路中管子磨损的增加是由一些因素共同引起的，例如蒸汽-水混合物的高速，弯头的可用性，以及在焊接位置对准管道的质量不理想。腐蚀是由两相高速射流在管壁上的强烈动力作用引起的。给出了减少热量回收蒸汽发生器管磨损的一般建议。已经确定，在Kirishi DPP的P-132蒸汽发生器低压回路中管子磨损的增加是由一些因素共同引起的，例如蒸汽-水混合物的高速，弯头的可用性，以及在焊接位置对准管道的质量不理想。腐蚀是由两相高速射流在管壁上的强烈动力作用引起的。给出了减少热量回收蒸汽发生器管磨损的一般建议。已经确定，在Kirishi DPP的P-132蒸汽发生器低压回路中管子磨损的增加是由一些因素共同引起的，例如蒸汽-水混合物的高速，弯头的可用性，以及在焊接位置对准管道的质量不理想。