Research On Synthesis Of PESA And Performance Of Its Combinated Scale Inhibitors

With the unprecedented development of industry, China is now facing the terrible problem of shorting water resource. The circulation cooling water system is advantagous to economize water and protect environment, and is more reasonable technology. So it is extensively used in metallurgy, chemical industry and other industrial departments. But the circulation cooling water system exists lots of questions, such as scale,corrosion and bacterium grouth etc. . Therefore, scale inhibition becomes more important today for protecting metal material and inhibiting scale, in order to save water and protect environment.This research aims at synthesizing the scale inhibitor of PESA, and testing the scale inhibition ability, the biodegradability and corrosion function of PESA is also investigated. Some scale inhibitors and corrosion inhibitors are combinated with PESA to get better inhibitor formula and anti-corrosion performance.PESA scale inhibitor is synthesized. some factors are discussed in the process of epoxidation and polyreaction with single factor experiment method and orthogonal experiment method. In the process of epoxidation, the optimum epoxidation experiments conditions are as follows: epoxidation temp T=65℃,pH=4.5, 12mL of H₂O₂(hydrogen peroxide), 2h of reaction time; in the process of polyreaction, the optimum polymerization conditions are as follows: the reaction temperature is 95℃,the molar ration of the inhibitor is0.15:1, the initiator is two-batches added, the reaction time is 2 hours.According to the experiment of inhibiting CaCO₃ on PESA, the following conclusions can be deduced from the tests: (1) polyepoxysuccinic acid(PESA) is a good inhibitor on calcium carbonate scale. Its scale inhibition efficiency improves if its concentration in aqueous system increases, it is found that they have good thermo stability and can be used in cooling water system with high pH,high concentration of calcium and alkalinity in a certain close. The high scale inhibiting ability can still be remained even after staying in high temperature for a long time. (2) PESA is also a good inhibitor on calcium sulfate, but the capacity of PESA on inhibiting calcium phosphate, ferric oxide dispersion, stabilizing Zn²⁺ is not ideal.To increasing the inhibition efficiency of inhibitors, polyepoxysuccinic acid(PESA) and natural scale inhibitor and copolymer is combinated. Some different recipes of combinated scale inhibitors is prepared. The test of scale inhibition properties of the combinated scale inhibitors indicates that the combination has excellent inhibition effect on the CaCO₃,Ca₃(PO₄)₂ and stabilizing Zn²⁺ in the cooling water system. The static metal hanging slice test and dynamic test are used for testing the effect of corrosion. Although the PESA has corrosion function in some degree, it can't meet the needs of industry. Some corrosion inhibitors, like inorganic corrosion inhibitor or BTA, are combinated respectively with PESA to improve the effect of corrosion, and the result show that the combined corrosion inhibitors has better corrosion efficiency than those corrosion inhibitors that just use single inhibitor.The biodegradability of polyepoxysuccinic acid (PESA) under different conditions has been introduced by the shaking-bottle incubating test. The results indicate that PESA has good biodegradability, and the biodegradability of PESA with high concentrate activated sludge is better than the low one. Besides, some comparable experiments for biodegradability are done among PESA and other inhibitors. The test indicates that the ability of the biodegrade has crucial relations to the molecular structure of polymer, the speed of biodegrading and the ability of biodegrading relies on the molecular structure.