Preparation And Performance Measurement Of DG3 Corrosion And Scale Inhibitor

The phenomena of corrosion and scale of industry equipment could be seen in all industrial productioa Therefore, some measures must be taken to solve these problems. One of the best ways was using corrosion and scale inhibitors. In order to improve the performance of corrosion rind scale inhibiting and protect environment from polluting, a new corrosion and scale inhibitor compound had been investigated in this paper.DGl, one of efficient components in DG3, had been studied by former investigators of our group. But some problems still remained, for example its concentration was low and the performance was not enough better using DGl or BTA alone. By optimizing the process of synthesizing and crystallizing, the purity of DG1 increased by far. In order to enhance the corrosion efficiency of DG1, DG2 was obtained, which was combined DGl with BTA at appropriate proportion. Besides these, a new series highly effective corrosion inhibitor and scale control agent of copper (DG3) was made up of DG2 and the best effective scale inhibitor screening from five commercial products.The results showed that the optimal synthesis condition of DGl was that the excess degree of caustic soda exceeds was 40%, reaction temperature was 95℃, the reflux time was 90 minutes and the reaction time was 60 minutes. In this condition the purity of crude DG1 had increased to 83.6%, which was 3% higher than that of the product made from the former process. By agitating in the process of recrystallization, DGl could be concentrated to 97.3%, which was 3% higher than that of the DG1 getting by former process. The corrosion test results showed that the corrosion efficiency of DG2 was better than that of BTA or DG1, which was formed by DGl and BTA at the ratio of two (2mg/L) and three (3mg/L). If adding DG2 into medium (fresh water or seawater) at 70℃, the corrosion speed of tin brass was 0.0020mm/L in fresh water and 0.0202mm/L in sea water in 70. However, it was 0.0022 mm/a and 0.0358 mm/a while using BTA alone in the same condition. In the five commercial scale inhibitors, PBTCA (5mg/L) had the best performance, which can tolerate 238.05 mg/L Ca2+ in fresh water at 30℃. By means of electrochemical polarization, weight-loss and bubble, the corrosion inhibiting and scale control efficiency of DG3 had been evaluated. The results indicated that DG3 was excel to DG1 or BTA, but the corrosion speed in the medium with DG3 was close to that with DG2, which were 0.0021mm/a and 0.0020 mm/a respectively. They all were lower than 0.0050mm/a (GB). The surface of tin brass which exposured in medium with DG3 was as bright as that exposured in medium with DG2 and there was no pitting and crevice corrosion.As far as the scale control efficiency concerned, DG3 had almost the same efficiency with PBTCA. Besides that, DG3 was more economic and environment-friendly.According to the results, it could easily concluded that DG3 was a new highly effective corrosion inhibitor and scale control agent, which had not been reported at home and abroad.