Optimization of Compounding Corrosion Inhibitor by Response Surface Methodology for Wastewater Containing Alcohol in a Gas Field

In order to solve the problem of serious corrosion in the recovery unit of wastewater containing alcohol in a gas field in Ordos, the corrosion causes of the key equipment of the unit were analyzed. The main corrosion inhibitor was selected from five self-developed BH type corrosion inhibitors of imidazoline, and mixed with two additives of IS-DSS and ACA-4. Based on the single factor experiment, the response surface method was used to optimize the composite inhibitors. The results show that under the action of H₂S, CO₂, HCO₃^-, Cl^-, non-protective corrosion products such as Fe₃S₄, Fe₂O₃, FeO, Fe(OH)₃ formed on the surface of the equipment were the main cause of the corrosion. The inhibitor BH-1 had the best effect of corrosion inhibition. The composite corrosion inhibitor obtained by combining IS-DSS and ACA-4 with BH-1 as the main agent could achieve synergistic corrosion inhibition. The inhibition efficiency of the composite corrosion inhibitors could reach 97.71%, when the dosages of BH-1, IS-DSS and ACA-4 were 90.59 mg/L, 30.44 mg/L and 40.00 mg/L, respectively.