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蒸汽锅炉化学清洗除垢过程的最后阶段要对受清洗的金属表面进行钝化处理,其目的是巩固化学清洗效果,保护受洗表面在使用前的十分敏感的时期免遭二次腐蚀,是锅炉化学清洗过程不可忽视的重要阶段。许多锅炉因大修、季节运行、调峰等原因短期或较长期停用,防止停用期间的腐蚀和防护往往比运行中更重要。各种化学清洗钝化剂和钝化工艺已沿用多年,为各方认可,其中以NaNO_2为最佳,其他如氨-联胺、磷酸盐等也都有效,但是这些药剂都会对环境产生影响,受到排放限制,虽然也出现了一些新的
Steam boiler chemical cleaning The final stage of the descaling process is to passivate the surface of the metal to be cleaned in order to consolidate the chemical cleaning effect and to protect the washed surface from secondary corrosion during very sensitive periods prior to use. Cleaning process can not be ignored an important stage. Many boilers are short-term or longer-term decommissioned due to overhauls, seasonal runs, peaking, etc., and corrosion and containment during decommissioning are often more important than running. A variety of chemical cleaning passivation agent and passivation process has been used for many years, recognized by all parties, of which NaNO_2 is the best, others such as ammonia - hydrazine, phosphate, etc. are also effective, but these agents will have an impact on the environment, Subject to emissions restrictions, although some new ones have emerged