钢铁企业中水管道的腐蚀行为与缓蚀防护研究

Study on the Corrosion Behavior and Inhibitor Protection in Reclaimed Water Pipelines of Steel Enterprises

针对湖南某钢铁企业中水输送管道的腐蚀问题,采集典型的中水水源点的水样进行水质检测。通过挂片试验、微生物培养计数、电化学测试、扫描电镜(SEM)、能谱(EDS)和X射线衍射(XRD)等系统地研究了中水输送管道的腐蚀行为,以及羟基乙叉二磷酸(HEDP)、2-磷酸基-1,2,4-三羧酸丁烷(PBTCA)和聚天冬氨酸(PASP)的缓蚀作用。结果表明:生物脱酚废水、高炉排水、五米板方向总排水和三水站排水对中水水质影响较大。中水管道表面的钝化膜在水中Cl^(-)和SO_(4)^(2-)的作用下被破坏,铁细菌和硫酸盐还原菌促进腐蚀并生成Fe(OH)_(3)和FeS。投加HEDP、PBTCA缓蚀剂后,腐蚀层厚度减小,腐蚀速率低于国家标准,而加入PASP后挂片表面的腐蚀产物为疏松多孔的菱铁矿,阻抗低频区表现为Warburg阻抗特征,缓蚀率仅为3.9%。

For the corrosion problem within the reclaimed water transport pipelines of a steel company in Hunan,water samples from typical reclaimed water sources were collected for water quality analysis.The corrosion behavior of the reclaimed water transport pipelines was systemat-ically investigated through hanging plate tests,microbial culture counting,electrochemical testing,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).Moreover,the corrosion inhibitory effects of hydroxyethylidene diphos-phonic acid(HEDP),2-Phosphonobutane-1,2,4-Tricarboxylic Acid(PBTCA)and polyaspartic acid(PASP)were examined.Results showed that the quality of reclaimed water was significantly impacted by biological dephenolization wastewater,blast furnace drainage,total drainage in the direction of five meters and drainage from three water stations.The passivation film on the surface of reclaimed water pipelines was destroyed by the action of Cl^(-)and SO_(4)^(2-)in the water,while iron bacteria and sulfate-reducing bacteria promoted corrosion,resulting in the formation of Fe(OH)_(3) and FeS.After the addition of HEDP and PBTCA corrosion inhibitors,a decrease in the thickness of the corrosion layer was observed,and the corrosion rate fell below the national standard.Following the addition of PASP,the corrosion products on the surface of the hanging plate were loose and porous siderite.In the low-frequency impedance region,Warburg impedance characteristics were displayed,and the corrosion inhibition rate was only 3.9%.