The Preparation Of New Corrosion Inhibitor With High Temperature Resistance

Carbon steel is widely used, while the corrosion inhibitor which is used as acid cleaning for mud acid under high temperature condition is not yet reported. By comparing dozens of organic compounds’loss weight with weight loss method, several compounds with good corrosion inhibition effect have been obtained for Carbon steel in mud acid solution, containing alkynol, aldehydes and heterocyclic compound.Propiolic alcohol, butynediol, benzalkonium chloride and hexamethylene tetramine were selected as object of study. The mechanism of corrosion inhibition action has been analyzed according to adsorption theory and electrochemical polarization-curve method in different temperatures.The result shows that the single molecule layer of these compounds which have been adsorbed on the surface of the carbon steel and followed Langmuir isothermal equation. The adsorption procedure was exothermic reaction, the adsorptive capacity and corrosion inhibition efficiency decreased with temperature increasing. Cetyl pyridinium bormide is anodic type inhibitor, the others are all mixed type inhibitor The corrosion current was decreased by them in different degree.In high temperature, corrosion inhibition efficiency of these compounds is low and can’t meet practical require. Because of this, two composite corrosion inhibitors, S-1and S-2, with excellent corrosion inhibition efficiency were composed by orthogonal method, corrosion inhibition capacity of S-1has been evaluated. The corrosion rate of carbon steel in mud acid has been determined under different temperatures, different concentration of mud acid, and different time. The SEM pictures of carbon steel surface have been got under different corrosion condition. When temperature was90℃, the concentration of mud acid solution (HCl:HF=7:3) was20%, the reaction time was24hours, the corrosion velocity of steel consistented with national standard (<6g·m-2·h-1). It shows that this composite corrosion inhibitor is characterized by great corrosion inhibition of anti-temperature, anti-acidity, and anti-time, it’s an excellent high-temperature corrosion inhibitor in mud acid solution.