MEA捕集CO_2腐蚀研究进展

Research Progress on Corrosion of Carbon Steel During Process of Capture CO_2 with Monoethanolamine Solution

介绍了单乙醇胺(MEA)溶液捕集CO_2过程中的腐蚀机理,以及O_2浓度、MEA浓度、溶液温度、CO_2浓度、热稳定盐对溶液腐蚀性的影响。结果表明,碳钢在MEA—CO_2溶液中存在电化学反应,阳极反应为铁失电子生成铁离子,阴极反应为游离水、水合氢离子、碳酸氢根离子以及氧得电子。腐蚀产物主要为FeCO_3、Fe(OH)_2和Fe(OH)_3。O_2浓度升高、MEA浓度升高、溶液温度升高、CO_2浓度增大、热稳定盐浓度升高等均可使溶液腐蚀性增强。不同种类热稳定盐对溶液腐蚀性影响不同,其中草酸盐对溶液腐蚀影响最大。CO_2捕集过程中的腐蚀问题常通过添加缓蚀剂来得到缓解。无机缓蚀剂腐蚀抑制效果好,但毒性大;有机缓蚀剂毒性较低,但腐蚀抑制效果较差。

This paper analyzes the corrosion mechanism of carbon steel during the process of capture CO2 with monoethanolamine（MEA） solution in terms of the effect of O2 concentration, MEA concentration, solution temperature, CO2 concentration and heat stable salts on the corrosivity of the MEA-CO2 solution. The results show that there exist electrochemical reactions in the MEA-CO2 solution, the anode reaction is that iron losses electrons to generate iron ions, the cathodic reaction results in free water, hydrated hydrogen ions, bicarbonate ions and oxygen gaining electrons. The main corrosion products are FeCO3, Fe（OH）2, Fe（OH）3. The rise of O2 concentration, MEA concentration, solution temperature and CO2 concentration will increase the corrosivity of the solution. Different types of heat stable salts have different effect on the corrosivity of the solution, among which the oxalate has the greatest effect on the corrosivity of the solution. The corrosion problem in the CO2 capture process is usually alleviated by adding corrosion inhibitor. Inorganic corrosion inhibitor presents good corrosion inhibition effect, but with high toxicity. Organic corrosion inhibitor toxicity is low, but with poor corrosion inhibition effect.