Corrosion Behavior of Carbon Steel at Typical Positions of an Amine-Based CO2 Capture Pilot Plant

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• 作者：Jubao Gao ; Shujuan Wang ; Chenchen Sun ; Bo Zhao ; Changhe Chen
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：May 16, 2012
• 年：2012
• 卷：51
• 期：19
• 页码：6714-6721
• 全文大小：520K
• 年卷期：v.51,no.19(May 16, 2012)
• ISSN：1520-5045

文摘

Corrosion tests of carbon steel at six typical positions in a CO₂ capture pilot plant using amine-based solvent were conducted with simulated flue gas (12 vol % CO₂, 18 vol % O₂ and 214 ppm SO₂). A weight-loss method was used to determine the corrosion rates for about 400 h of experiment. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to analyze the morphology and compositions of the coupon surface and cross section. The corrosion products on the sample's surface and cross section were analyzed with X-ray diffraction and Raman spectroscopy, respectively. Experimental and theoretical analyses show that the higher corrosion rates among these positions were present at the bottom of the absorber and rich liquid outlet of the rich-lean heat exchanger. The double-layer structure of the corrosion products with different colors was obviously observed on the cross sectional surface of the coupons at the absorber bottom and the stripper inlet. The corrosion products in the inner layer are mainly composed of hematite (伪-Fe₂O₃) and magnetite (Fe₃O₄) with traces of goethite (伪-FeOOH), while the outer layer mainly consists of siderite (FeCO₃). The inner corrosion products, including 伪-Fe₂O₃, Fe₃O₄, and 伪-FeOOH, may come from the decomposition of FeCO₃ in the amine-H₂O鈥揅O₂鈥揙₂鈥揝O₂ system. An addition of SO₂ yields large amounts of hydrogen ion and dissolved oxygen which may induce a higher corrosion rate.