Corrosion Characteristics For CO₂ Capture Process Using Functionalized Ionic Liquids Activated Amine Aqueous Solution

The absorption of carbon dioxide（CO₂）by alkynolamine solution is the most widely used carbon capture method in the industry,but the high concentration of the amine solution will corrode the absorption equipment.The main purpose of this work is to investigate the corrosion behaviors of carbon steel in carbonated amine solutions.Ionic liquid（ILs）(1-butyl-3-methyl-imidazolium lysinate（[Bmim][Lys]）,tetramethylammoniumlysinate([N₁₁₁₁][Lys]))compoundedwith N-methyldiethanolamine（MDEA）were used as absorbents.The temperatures ranged from 303.2K to 323.2K.The mass fraction of ILs and MDEA ranged from 0 to 0.15and 0.3 to 0.4,respectively.The CO₂ loading ranged from 0.1 to 0.5.The corresponding corrosion rates is calculated.The effect of the mass fraction of MDEA and ILs,solution temperature,CO₂ loading and pH on the corrosion rates were demonstrated.Our results showed that:1)In the carbonated MDEA-ILs aqueous solutions,the corrosion rate of carbon steel increases with the increase of the mass fraction of MDEA,temperature and CO₂loading,and decreases with the increase of the concentration of ILs;2)The aqueous solution of MDEA and the ILs has a higher absorption capacity for CO₂.The more is the absorbed CO₂,the smaller the pH value and the greater the corrosion rate.3)The increase of the solution temperature leads to an increase in the anode current density and the cathode current density.The reduction of the corrosion process by the reduction of the metal dissolver and the oxidant causes more severer corrosion of the carbon steel.In a CO₂-ILs-MDEA aqueous solution,the increase of the CO₂loading results in a larger cathode current density,but it has less impact on the anode current density.