1 、引言
随着全球经济持续发展和人民生活水平日益提高，未来的工业及热力需求仍将保持增长态势，各地区将纷纷建起大容量、高参数、多样化大型电站。锅炉是电站的核心设备之一，主要是将燃料燃烧转化为热能后将工质加热成合格参数的过热蒸汽为汽轮机提供动能。电站锅炉安装完成后需进行整体水压试验以验证锅炉的安装质量及整体严密性，保证锅炉安全、稳定、可靠运行。水压试验用水质量标准是锅炉水压试验需考虑的重要因素，许多锅炉运行期间的腐蚀和开裂都是因为水压试验用水选用不合理导致的。
现“一带一路”建设不断推进发展，越来越多的中国企业扬帆出海，走出国门，在东南亚、南亚、中东北非、南美等地区承建各类大型电站。电站建设地区和国家的不同，建设执行的标准也不尽相同，锅炉水压试验用水标准中规定也因标准而已。本文将根据国内标准、国际标准、厂家指导意见进行分析各标准下的锅炉水压试验用水标准要求，供相应单位参考。
2 、国内相关标准
国内相关标准规定列举如下：
《电力建设施工技术规范 第2部分：锅炉机组》DL-5190.2-2019版中5.10.5条：水压试验的水质应符合设备技术文件规定，无规定时，应按《电力基本建设热力设备化学监督导则》DL/T 889的有关规定执行。
《电力基本建设热力设备化学监督导则》DL／T 889-2015版中6.4.2条：锅炉整体水压试验应采用除盐水；6.4.3条：锅炉做整体水压试验时，除盐水中应加有一定剂量的氨，调节PH值10.5以上。过热器、再热器溢出液中的氯离子含量应小于0.2mg/L。
《电力建设施工质量验收规程 第2部分：锅炉机组》DL 5210.2-2018版中表6.7.1：水压试验用水质量标准采用合格的除盐水。
《电力工业锅炉压力容器监察规程》DL 612-2017 版中11.2.3条：锅炉整体水压试验时，应采用除盐水，除盐水应加有一定剂量的氨，调节PH值至10.5以上。过热器、再热器溢出液中的氯离子含量应小于0.2mg/L。
《火力发电工程建设标准强制性条文实施指南》2013版中施炉表6《锅炉水压试验强制性条文明细表》中第3条引用《电站锅炉压力容器检验规程》DL 647-2004规定：5.13 b蒸汽压力为9.8Mpa以下锅炉的水压试验，采用除盐水或软化水。c蒸汽压力为9.8Mpa以上锅炉的水压试验，采用除盐水。整体水压试验用水质量应满足下列要求：1）采用除盐水时，氯离子含量小于0.2mg/L。2）联氨和丙酮肟含量200mg/l—300mg/l。3）PH值为10-10.5（用氨水调节）。
《锅炉安全技术监察规程》TSG G11-2020第123条要求：水压试验所用谁应当是洁净水。奥氏体受压元件水压试验时，应当控制水中的氯离子含量不超过25mg/L。试验合格后，应当立即将水渍去除干净。
在国内施工时一般依据相关最新版标准规定，若标准不一致时，则执行高标准。由此在国内电站锅炉水压试验用水一般采用PH值10.5以上、氯离子含量小于0.2mg/L的除盐水。
3 、国际相关标准
国际相关标准规定列举如下：
ASME标准《 B31.1 Power Piping》中137.4.3条：Test Medium Test water shall be clean and shall be of such quality as to minimize corrosion of the materials in the piping system. Further recommended precautions on the quality of test water used for hydrotesting of austenitic (300 series) and ferritic (400 series) stainless steels are contained in non mandatory Appendix IV, para. IV-3.4.
IV-3.4条：Precautions at Hydro testing Equipment fabricated from austenitic (300 series) and ferritic (400 series) stainless steels and requiring hydrostatic testing should be tested with deionized water, high purity steam condensate, or potable water, in decreasing order of preference.NOTE: Potable water in this context follows U.S. practice, with 250 parts per million maximum chloride content, sanitized with chlorine or ozone.After testing is completed, equipment should be thoroughly drained with all high point vents open during draining, and dried by air blowing, swabbing, or other appropriate means. If immediate draining and drying are not possible, hydrotest water should be circulated in the piping for at least one hour daily to reduce the possibility of pitting and microbiologically influenced corrosion.
ASME标准《B31.3 Process Piping》中F345.4.1条：Hydrostatic Leak Test Consideration should be given to susceptibility to microbiologically influenced corrosion (MIC). This condition is especially prevalent in no-flow, high-moisture environments. Internal MIC may also depend on the characteristics of the treated or untreated test fluid. Internal MIC may be lessened or possibly eliminated by properly draining and drying systems and/or by proper selection of test fluid.
ASME标准《PCC-2 - Pressure vessel and Piping Repair》中 6.1条：The use of salt or brackish water should be avoided. Test water should be free from sediment and corrosive substances.The test water should be verified to be free of microbes. If the water contains an unacceptable level of microbes, it should be disinfected.Test water used for austenitic steel vessels or piping systems, or for components clad or overlaid with austenitic stainless steel, should be condensate, demineralized, or of potable quality, with a verified chloride content of less than 50 ppm.Test liquid should be drained immediately after completion of the hydrostatic test. Care should be exercised to provide proper venting to prevent the creation of internal negative pressure (vacuum) during draining.Pressure vessels and/or piping systems that will hold the test water for more than 10 days, whether or not the test liquid is pressurized, should be treated with a corrosion inhibitor and biocide. A corrosion engineer should be consulted. If further drying is necessary, the use of hot air or hot nitrogen should be considered.If complete drainage of austenitic stainless steel vessels and/or piping systems is not possible, the components should be flushed with low-chloride (less than 5 ppm) water.
API 510《Pressure Vessel Inspection Code》5.8.5.2条：Hydrostatic pressure tests of equipment having components of Type 300 series stainless steel should be conducted with potable water or steam condensate having a chloride concentration of less than 50 ppm. After the test, the vessel should be completely drained and dried. The inspector should verify the specified water quality is used and that the vessel has been rained and dried (all high-point vents should be open during draining). If potable water is not available or if immediate draining and drying is not possible, water having a very low chloride level (e.g.steam condensate), higher pH (>10), and inhibitor addition should be considered to reduce the risk of pitting, chloride stress corrosion cracking, and microbiologically induced corrosion. For sensitized austenitic stainless steel piping subject to polythionic stress corrosion cracking, consideration should be given to using an alkaline-water solution for pressure testing (see NACE SP0170).
API 570《Piping Inspection Code》5.11.2条：Piping fabricated of or having components of austenitic stainless steel should be hydrotested with a solution made up of potable water (see note), de-ionized/de-mineralized water or steam condensate having a total chloride concentration (not free chlorine concentration) of less than 50 ppm. After testing is completed, the piping should be thoroughly drained (all high-point vents should be open during draining), air blown, or otherwise dried. If potable water is not available or if immediate draining and drying is not possible, water having a very low chloride level, higher pH (>10), and inhibitor addition may be considered to reduce the risk of pitting and microbiologically induced corrosion.
以上涉及部分国际标准，电站锅炉施工方应根据锅炉设计安装执行标准选用相关符合标准的水质进行水压试验。
4 、结论
锅炉水压试验用水水质标准在国内施工的锅炉整体水压试验时应符合最新版标准及强制性条文规定，在国际施工过程中优先依据锅炉厂家指导设计意见选用锅炉水压试验用水标准，若无指导意见，可根据项目所处国家工业水平，与业主及咨询监理方协商参照国际、国家、行业执行的相关标准选用锅炉水压试验用水水质标准进行锅炉整体水压试验，快速推进工程进展。
作者简介：吴兴泊(1991.4-)，男，汉族，山东菏泽，大学本科，工程师，研究方向：电站锅炉。
参考文献：
[1] 浅析电站锅炉水压试验标准[D]. 张磊.2014
[2] 电站锅炉与压力容器水压试验标准执行研究[D]. 王婧，杨祎，李慧萍. 2019