火电厂过热器化学清洗配方及工艺研究

Study on Superheater Chemical Cleaning with Different Agents

清洗锅炉过热器时若出现氧化皮大量剥落,会造成堵管风险;若清洗介质选择不当会造成材料性能下降。因此,必须充分考虑清洗介质对各种过热器管材表面氧化皮的剥离作用,以及对剥落氧化皮的溶解效果和对所有材料的腐蚀情况。选择EDTA铵盐、EDTA钠盐、柠檬酸、羟基乙酸+甲酸、自制复合有机酸A和自制复合有机酸B等清洗介质进行了氧化皮剥离量、管样除垢率、剥落氧化皮的溶解率试验,并采用上述清洗介质对T22、12Cr1MoV、T91、TP347等4种过热器金属材料进行了腐蚀试验。研究结果表明,同时满足氧化皮剥离量小、管样除垢率高、氧化皮溶解效果好、腐蚀风险小的清洗介质为复合有机酸B。

During the chemical cleaning of superheater, flaking, dissolution and corrosion of the cleaning agents must be taken into account in case of tube blockage caused by mass oxide flakes. Moreover, material performance may deteriorate as a result of improper cleaning agents. Therefore, tests on oxide flake volume and solubility as well as the descaling rate for superheater tubes adopting the cleaning agents such as NH4-EDTA, Na-EDTA, citric acid, hydroxyl acetic acid ＋ tormic acid, complex-organic-acid-A and complex-organic-acid-B, are carried out. And corrosion tests on four kinds of superheater materials, i.e., T22, 12CrlMoV, T91 and TP347 adopting these cleaning agents are also conducted. The test results indicate that complex-organic-aeid-B is the right one with small flaking oxide volume, high oxide dissolution rate and low corrosion rate.