工况对R22及替代工质有效过热循环性能的影响

为解决R22替代过程中制冷系统回热器的再设计问题,以热力学计算分析的方法对运行工况参数对R22及其7种替代制冷剂的有效过热循环性能的影响进行了研究.结果表明,决定有效过热对制冷循环的性能是否有利的因素除了工质种类外。还有运行工况参数;有效过热对R22、R152a和R410A的制冷循环性能的影响是否有利取决于具体工况;有效过热对R407C、R134a、R290和R507的制冷循环性能的影响总是有利的,而对R717的制冷循环的性能总有负面影响.     

Possible scenarios for the causes of accelerated fireside corrosion of superheater tubes in coal-fired boilers

Recent experience of rapid corrosion of superheater tubes in coal-fired boilers has led to the application of weld-overlay coatings, which have proved effective but are expensive and can degrade mechanical tube life. Lack of understanding of how such corrosion differs from the established mechanism involving low-melting, complex, alkali-iron trisulphates is a major obstacle to devising alternative protective measures. Suggested scenarios for such accelerated corrosion are considered, including (1) increased tube surface temperatures allowing other sulphate mixtures to melt, analogous to Hot Corrosion mechanisms in gas turbines; (2) changes in the corrosivity of tube deposits from carryover of reduced species; and (3) increased release of corrosive species from the coal under substoichiometric combustion conditions. The potential for such scenarios to change the corrosive environment is assessed on the basis of current mechanistic understanding, though the general lack of phase diagrams for relevant ternary and quaternary sulphate systems is a major drawback to specifying the processes involved.     

锅炉受热面蒸汽吹灰的研究

蒸汽吹灰是清除蒸汽过热器，对流过热器和屏式过热器表面污染的普遍方法，通过试验总结出蒸汽吹灰可以长期保持蒸汽过热器的热效率和降低污染程度。     

锅炉过热器炉内壁面温度红外测量信号的波动特征及数据处理方法

电站锅炉系统中,过热器管壁温度是非常重要的监测参数,关系到机组的安全及高效运行。该文模拟电站锅炉内过热器管壁测温条件,开展了一维炉实验台内不锈钢平板表面温度辐射法测量研究,对实验结果进行了时域和频域的分析。结果表明,红外温度计测量所得试件表面温度会有一定的波动,具有随机性和周期性的特征。红外温度计所测温度与管壁真实温度有一定的偏差。在实验分析的基础上,提出小波消噪和温度修正相结合的数据处理方法,提高了辐射测温精度,为准确测量锅炉内过热器管壁温度提供了参考。