Study Of Corrosion And Scale Inhibitors In Near Neutral Mediums

Both scale and corrosion are the most serious problems in the near neutral mediums. Polyaspartic acid (PASP) is a novel biodegradable water-treatment agent developed in recent years. It has good properties such as scale inhibition, dispersancy and corrosion inhibition. 1-hydroxyethlidene-1, 1-diphosphonic acid (HEDP) is a new-style corrosion and scale inhibitor.In this article, the character of the PASP and its derivates are studied. The derivative is prepared by glycin reacts with the mid-product, which is produced in the combination of PASP synthesis, and the corrosion and scale inhibition efficiency are preliminary investigated. Experimental results show that the scale inhibiton of PASP isn't improved, but the corrosion inhibition efficiency of PASP is remarkably improved by inducing carboxyl to the compound.The corrosion inhibitor HG1, which is based on the HEDP, is prepared and studied. It is an effective anodic type corrosion inhibitor and has good inhibition efficiency for corrosion of carbon steel in the simulated oilfield production water.The inhibition effect of corrosion inhibitors such as EC, HG1 and HG2 in simulated oilfield production water (pH=7.7) is studied by using weight loss method, Tafel polarization curve and linear polarization technology. The applicability of using time integral of the reciprocal of linear polarization resistance for evaluating corrosion inhibitors is also discussed. Experimental results show that the evaluation result obtained by using the integral of the reciprocal of linear polarization resistance is consistent with that obtained by weight loss method.