Study On The Combinating Application And Performance Of Low Phosphonic Corrosion And Scale Inhibitor Of Phosphono Carboxylic Acid

By the research of the complex composition including phosphono-carboxylic-acid(POCA), 1-hydroxyethane,1-diphosphonicacid(HEDP), aminorimethylenephosphonic acid(ATMP), zinc acetate, the aim of this dissertation is to dissolve corrosion and scale problems in circulating cool water with medium or low hardness. The weight-loss and static scale inhibition methods were used, The corrosion inhibition ,scale inhibition and properties of complex composition was studied. By orthogonal test,a serials of complex composition including POCA was also studied. The rigidity, the pH and the temperature effect on the corrosion inhibiting performance of compound system were examined, and the concentration of complexion agent by orthogonal test was optimized, then a new corrosion and scale inhibitor compound had been investigated in this paper which is environmental, economical and effective. Finally, the mechanism of corrosion and scale inhibitor had been discussed.The result indicates that the calcium carbonate scale inhibiting performance of POCA is excellent. There is an excellence synergistic effect on the calcium carbonate scale inhibiting between POCA and PBTC, the two-component mixture of POCA and HEDP also has the similar result, but there is no synergistic effect between POCA and ATMP.the calcium phosphate scale inhibiting performance of POCA which has the high concentration is extremely ideal. It can be observed that there is no evident synergistic effect on the two-component mixture, such as POCA and PBTC ,POCA and HEDP.There is no significant synergistic effect among POCA, PBTC, HEDP and zinc acetate, the corrosion inhibiting performance of the quarternary system is good.The concentration ratios of calcium carbonate scale inhibitor compound draw the following conclutions: POCA:PBTC=3:2, POCA:HEDP=4:1, the anti-scale rate of the two compounds can achieve 100%; The calcium phosphate scale inhibiting efficiency of POCA that its concentration is exceed 20 mg/L equaled to 100%. A compound formula which anticorrosive rate has achieved 92.22%, antiscale rate of calcium carbonate is 90.42%, antiscale rate of calcium phosphate achieved 97.60%, contains 25 mg/L of POCA, 15 mg/L of HEDP, 20 mg/L of PBTC, 3 mg/L of zinc acetate while the composite system is an anode inhibition. .