Study On Preparation And Mechanism Of Environment-Friendly Scale And Corrosion Inhibitor

PASP receives much concern as the environment-friendly recirculated cooling water treatment agents. For the high cost and problems in equipment. PASP still hasn't been widely to apply in practical water treatment industry. This project synthesizes PASP on principle of simple technology, low production cost, high rate of finished products and easy production of industrialization. In the condition of 200℃, 180min and normal pressure, we had synthesized high performance-to-price ratio PASP which using inexpensive maleic anhydride and the urea as raw material. The new craft overcome completely tradition's defect, such as high temperature, the vacuum, long reaction time, complex equipment and so on.The article system studied the influence of synthesis conditions on scale inhibition of CaCO₃.We has determined the best molecular weight, and analyzed the influence of dosage on the scale inhibition ratio. Simultaneously ,we has studied scale inhibition of best molecular weight PASP to the calcium sulfate, the barium sulfate, the calcium phosphate . Scattered performance is also good. When the concentration of Ca²⁺ is 200mg/L, only 4mg/L PASP at 45℃, the rate of scale inhibition still can achieve over 90% 20 hours later. Moreover and under the high pH condition and high water temperature it also has good scale inhibition. The corrosion inhibition experiment indicated that PASP is a good scale inhibitor, but the corrosion inhibition effect is not very good. We should consider that uses together with other corrosion inhibitors, thus enhances corrosion inhibition effect. In the experiment, PASP compound with common corrosion inhibitors, its corrosion inhibition performance its inhibition performance will enhancement. Moreover its scale inhibition will not drop. When PASP compound with sodium gluconate, polyvinyl alcohol only needs 35mg/L its scale inhibition can above 95%, and the corrosion inhibition is smaller than 0.10mm/a.Finally article has carried on some discussions about the PASP mechanism of sale inhibition and corrosion inhibition. The mechanism of scale inhibition of PASP is chelated, lattice distortion, dispersion. But its main function lies in chelated. In corrosion inhibition aspect, PASP its inhibition's process has certain difference in the different environment, it can adsorb in the metal surface forms protective film, and therefore it belongs to one kind of adsorption membrane corrosion inhibitor.