Abstract

QUIROZ, Rosdely; ROSALES, Adalberto  and  BARON, Evaristo. Evaluation of CO₂ corrosion inhibition in a system with stratified multiphase fluid. Rev. Téc. Ing. Univ. Zulia [online]. 2007, vol.30, n.Especial, pp.261-271. ISSN 0254-0770.

The effect of corrosion inhibitor solubility on CO₂ corrosion control efficiency was electrochemically evaluated, in simulated stratified multiphase fluid. Solubility qualitative tests and linear polarization measurements were carried out, using API 5 L X / 42 carbon steel specimens, immersed in CO₂ saturated 3.5 wt% NaCl solution, at pH 3.5 and 25°C. To simulate a hydrocarbon phases a kerosene/ toluene/ diesel mixture was used. Two commercial inhibitors were evaluated, adding the inhibitor either on the hydrocarbon phase or on the aqueous phase. The corrosion inhibitor with high solubility in the hydrocarbon phase showed low corrosion inhibition efficiency. The product was not incorporated in the aqueous phase and as a result no interaction with the metallic surface occurred. The inhibitor exhibiting dispersibility in the hydrocarbon phase remained more available on the aqueous phase to interact with the metallic surface, given therefore a higher efficiency in corrosion control.

Keywords : CO₂ corrosion; corrosion inhibition; stratified flow; corrosion in multiphase system.