Corrosion inhibition performance of copper carbonate in carbon dioxide absorption process using aqueous solution of monoethanolamine.

摘要

Corrosion is one of the most severe operational problems in CO2 absorption processes, which use aqueous solutions of alkanolamines, especially when carbon steel is used for plant construction. Corrosion inhibitors are widely applied used in this process to suppress severe corrosion to an acceptable level. However, currently available corrosion inhibitors are heavy metals, which are toxic to human health and the environment, making solvent handling and waste disposal more difficult and costly. This work evaluated a low-toxic corrosion inhibitor, copper carbonate (CuCO3), as a replacement for toxic corrosion inhibitors. An inhibition evaluation was performed on copper carbonate by examining its parametric effects on the corrosion rate and corrosion behavior of carbon steel.;Results show that CuCO3 is an anodic corrosion inhibitor which suppresses the corrosion of carbon steel by raising the system's potential to the passive region where the passive film of hematite (Fe2O 3) is formed on the metal surface and acts as a barrier between the bulk solution and metal surface. CuCO3 offers satisfactory corrosion inhibition under typical service conditions in the CO2 absorption process. The corrosion rate of carbon steel is held below 0.254 mmpy and its inhibition efficiency is at least 80%. The inhibition performance of CuCO 3 is affected by partial pressure of O2, CuCO3 concentration, CO2 loading in solution, solution velocity, solution temperature, MEA concentration, cleanliness of the metal surface (pre-corrosion duration) and degradation products including reversible products and heat-stable salts. Dissolved oxygen (O2) is required for effective corrosion inhibition by CuCO3.