石灰混凝澄清处理产出水输送管道的腐蚀失效原因  

Corrosion Failure Causes of Transportation Pipeline for Produced Water of Lime Coagulation and Clarification Treatment

作　　者：刘德来 张建军 郝洪铎 方媛媛 张洪博[2] 肖海刚 LIU Delai;ZHANG Jianjun;HAO Hongduo;FANG Yuanyuan;ZHANG Hongbo;XIAO Haigang(Shanxi Coking Coal Xishan Coal Electricity Group Co.,Ltd.,Gujiao 030200,China;Xi'an Thermal Power Research Institute Co.,Ltd.,Xi'an 710000,China)

机构地区：[1]山西焦煤西山煤电集团有限责任公司,古交030200 [2]西安热工研究院有限公司,西安710000

出　　处：《腐蚀与防护》2023年第2期114-119,共6页Corrosion & Protection

摘　　要：山西某电厂用于输送石灰混凝澄清处理产出水的Q235B碳钢管道在投运后不久就发生了腐蚀泄漏。通过失效管道的理化检验和现场挂片试验,结合Lagelier经验指数对管道的腐蚀失效原因进行了分析。结果表明:在低碱度、高硬度的水质条件下,碳钢在水中的腐蚀反应导致微阴极区pH升高,诱导CaCO3快速成核沉积在碳钢表面,但并没有形成均匀的保护膜,反而由于碳钢表面沉积物的不均匀性形成了氧浓差电池,这是造成碳钢管道腐蚀失效的主要原因。A Q235B carbon steel pipeline for conveying produced water of lime coagulation and clarification treatment in a power plant in Shanxi Province corroded and leaked in a short period of time after operation.In this paper the corrosion failure causes of the pipeline were analyzed through physical and chemical inspection of the failed pipeline and field coupon tests,combined with Lagelier empirical index.The results indicated that the corrosion reaction of carbon steel in water led to the increase of pH in microcathode area,inducing the rapid nucleation and deposition of CaCO3 on the surface of carbon steel under the water condition of low alkalinity and high hardness.However,uniform protective film did not form under such conditions.Instead,oxygen concentration difference cells formed due to the heterogeneity of sediments on carbon steel surface,which was the main cause of the corrosion failure of the carbon steel pipeline.

关 键 词：石灰混凝澄清处理 碳钢腐蚀 钙碱度 硬度 经验指数 

分 类 号：TG174[金属学及工艺—金属表面处理]