Application of Doehlert experimental design for optimization of CO2 corrosion inhibition of API 5 L X70 steel in petroleum produced water

Corrosion is a serious problem that threatens the chemical and petrochemical industries, which can be controlled by using inhibitors. The present work paper examines the effectiveness of diethyl amine (DEA) as a corrosion inhibitor for API 5 L X70 steel in CO 2 -saturated oil field-produced water. The corrosion inhibition process was optimized using the Doehlert experimental design. Corrosion rates and other electrochemical parameters are evaluated by weight loss and electrochemical techniques. The influence of temperature, inhibitor concentrations, and corrosive solution velocity is studied. The highest inhibition efficiency of DEA was found to be 90.4% at a concentration of 3 × 10 −4 M. The addition of the inhibitor reduces both cathodic and anodic current densities and significantly enhances impedance parameters. Atomic force microscope (AFM), scanning electron microscope (SEM), and optical microscope (OM) analyses were conducted to assess the surface morphology of the steel. Additionally, quantum chemical calculations were performed to support the experimental results. The optimization of the corrosion inhibition process of steel alloys in CO 2 -satured saline water solution as a function of several variables was limited. Therefore, the innovative aspect and novelty of current work are to optimize the inhibitor performance via suggesting a mathematical model that takes into consideration the individual and interaction effects of independent variables.