Regression analysis of corrosion inhibition of 42CrMo4 steel: a case study of acidified large Maradol leaf extract, kinetic, thermodynamics, adsorptions, and process parameter optimization

In the oil and gas sector, corrosion results in catastrophic failures, leaks, and equipment degradation that cause enormous financial losses (billions of dollars every year), serious safety risks (fires, explosions, exposure to poisonous H2S), and significant environmental pollution (infection of land and water). Corrosive agents including H2S, CO2, water, and high temperatures cause asset integrity to be compromised, production to be disrupted by unplanned shutdowns, and maintenance, repair, and replacement costs to rise. Hence, this study attempt to minimize the corrosion rate (CR), and maximize the inhibition efficiency (IE) in oil and gas industry, response surface methodology and artificial neural network tools were used to study the effects of inhibition concentration, temperature, and time of the adsorption corrosion inhibition of 42CrMo4 steel in an acidified large Maradol Leaf Extract (LMLE) of green biomass. The phytochemicals analysis of the extract was examined, and the elemental composition of 42CrMo4 steel was ascertained. The weight loss method was computed via gravimetric analysis. The kinetic and thermodynamics parameters were carried out, while the adsorption isotherm was carried out via Langmuir, Frumkin, Temkin, and Flory-Huggin isotherms.Results shows that the compositions of the steel was majorly iron (Fe) contained 97.26%. The phytochemical analysis of the extract indicated the presence of flavonoids, phenols, saponins, alkaloids, tannins, steroids, and terpenoids found in organic biomass extract. Process modeling and optimization by central composite rotatable design (in RSM) shows a validated average minimum CR of 12.60 mm/yr and the optimum IE of 91.40%, while genetic algorithms (in ANN) validated an average minimum CR of 9.70 mm/yr and the optimum IE of 94.12%, respectively. From isotherms study, Langmuir isotherm model was found best fitted and described the corrosion inhibition mechanism of 42CrMo4 steel. Based on thermodynamic data, the negative ∆Gads from - 73.42 to - 140.42 kJ/mol connote chemisorptions adsorptions.The study concluded that the extract of large Maradol leaf when treated with 15% hydrochloric acid could serve inhibitor for treatment of 42CrMo4 steel corrosion in an oil well environment.