Corrosion behavior of carbon steel in H2S-CO2-H2O-methyldiethanolamine (MDEA) solution under the presence of chloride ions
Anti-Corrosion Methods and Materials
ISSN: 0003-5599
Article publication date: 26 July 2021
Issue publication date: 19 August 2021
Abstract
Purpose
This paper aims to study the effect of chloride ions concentration on the corrosion behavior of carbon steel in methyldiethanolamine (MDEA) aqueous solution in the sight of different process parameters of purification plant.
Design/methodology/approach
Due to the decrease of filtration efficiency and separation efficiency, the chloride ion in the desulfurization solution is enriched. The corrosion behavior of carbon steel under chloride ion enrichment environment was studied by weight-loss method, electrochemical impedance spectroscopy, cyclic polarization curve, X-ray photoelectron spectroscopy and scanning electron microscopy.
Findings
The results show that temperature and hydrogen sulfide loads are the main factors of corrosion in CO2-MDEA-H2O-H2S environment. The enrichment of chloride ions reduces the corrosion rate at low temperature but promotes the corrosion rate at high temperature. The chloride concentration should be controlled below 3000 mg/L, and no pitting corrosion was found under the experimental conditions.
Originality/value
The effect of chloride ion enrichment on MDEA solution corrosion shows that at low temperature, the increase of chloride ion will reduce the acid gas load and increase the density of corrosion products, so as to reduce the corrosion; on the contrary, at high temperature, the density of corrosion products will decrease and the corrosion will be intensified as well. It is believed that the chloride ion should be controlled below 3000 mg/L according to the results of the tests.
Keywords
Acknowledgements
This research has been supported by the project 20190303–27 funded by PetroChina Southwest Oil and Gasfield Company.
Citation
Wu, G., Gu, X., Zhao, W., Fan, R. and Mao, T. (2021), "Corrosion behavior of carbon steel in H2S-CO2-H2O-methyldiethanolamine (MDEA) solution under the presence of chloride ions", Anti-Corrosion Methods and Materials, Vol. 68 No. 4, pp. 284-292. https://doi.org/10.1108/ACMM-12-2020-2420
Publisher
:Emerald Publishing Limited
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