Laboratory investigation of the effectiveness of MDEA volatile corrosion inhibitor on mild steel - Top of the line corrosion

Fredric Ajayi, Stuart Lyon

    Research output: Contribution to conferencePoster

    Abstract

    Top of the line corrosion (TLC) is of great concern to the Oil and Gas Industry because of the difficulty of protecting the upper wall of pipelines using conventional corrosion inhibitors. The effectiveness of methyl diethanolamine (MDEA), a volatile corrosion inhibitor and/or a pH stabilizer on mild steel TLC was investigated using a glass cell containing 1% NaCl and 100ppm acetic acid with addition of 100ppm MDEA saturated with CO2 gas (0.6bar partial pressure) at 60oC for a period of 100 hours. Electrochemical measurements were carried out by electrochemical impedance spectroscopy (eIS) and linear polarisation resistance (LPR). Presence of acetic acid in the condensed water increased the corrosion rate because it unbufferred the condensate resulting in low pH (4.30); addition of MDEA to the wet gas resulted in a significant reduction in the corrosion rate because it acted as pH stabilizer, favouring iron carbonate formation which acts as a barrier to further iron dissolution. The results of the effectiveness of MDEA as a function of time shown in the figure below confirmed that the addition of 100ppm MDEA as a volatile corrosion inhibitor to mitigate TLC is very effective up to 50hrs when lowest corrosion rate and maximum inhibition efficiency of 89 and 92% for EIS and LPR respectively were recorded.
    Original languageEnglish
    Publication statusPublished - 2013
    EventEuropean Corrosion Congress, EUROCORR 2013 - Estoril
    Duration: 1 Jul 2013 → …

    Conference

    ConferenceEuropean Corrosion Congress, EUROCORR 2013
    CityEstoril
    Period1/07/13 → …

    Keywords

    • Carbon dioxide, pipelines, volatile corrosion inhibitors, top of the line corrosion

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