Research On Synthesis Of Polyepoxysuccinic Acid And Performance Of Its Scale And Corrosion Inhibition

Polyepoxysuccinic acid is acknowledged green water treatment agent in the world, because of its excellent performance of scale inhibition,corrosion inhibition, biodegradability and unique molecular structure having no hetero-atoms such as phosphorus and nitrogen.It appears in recent years,so there are many problems in product development and application. For example, the research report about the applications of PESA in oilfield water treatment are less,the research about molecular weight control and the relationship between PESA and its relative molecular weight need to go further. So these problems to some extent confine its industrial application.Based on the above problems,this study take the relative molecular weight and the yield as indexes to explore the synthesis conditions,and turned out that the performance of PESA is relative to its relative molecular weight,and preliminary analysis of the scale inhibition mechanism and the inhibition mechanism. In this way, we can provide some references for PESA’s practical applications in oil field.In the process of epoxidation,the optimum epoxidation experiments conditions have been obtained by orthogonal experiment and single factor experiment. The optimized conditions is molar ratio of catalyst to maleic anhydride(0.03:1), reaction time1.5h,reaction system pH5.5, reaction temperature65℃,volume ratio of ethanol to water(4:1).Under the conditions,the product is prepared in the yield of about95%and characterized by IR.Polyepoxysuccinic acid was synthesized in virtue of anionic polymerization.After investigating six factors that influenced relative molecular mass of polyepoxysuccinic acid independently, the optimized reaction conditions have been obtained. Under the optimized conditions, a series of scale inhibitors whose molecular weights are between350～1300were prepared in the yield of more than65%.And the polyepoxysuccinic acid which molecular weight at1266was synthesized by the condition that molar ratio of initiator to ESA(0.06:1),reaction time2.5h,reaction system pH13, reaction temperature95℃,the product is prepared in the yield of86.75%.Then, the methods of calcium carbonate deposition and conductivity titration analysis has been used to analyze and evaluate the scale inhibition performance of the synthesized polyepoxysuccinic acids.It turned out that PESA has excellent scale inhibition on calcium carbonate, strontium sulfate and barium sulfate,especially the scale inhibitors whose relative molecular weights are between1100-1300have better scale inhibition performance.The scale inhibition rate can reach to more than90%for Sr2+,Ba2+and low concentration of Ca2+.There is a good "Threshold effect " when using these PESAs. The optimum dosage and the relative molecular weight of PESA should be selected according to the different concentration and type of scale in practical application. The scale inhibition mechanism of polyepoxysuccinic acid was also preliminarily discussed by means of scanning electron microscopy(SEM).The static metal hanging slice test has been used to analyze and evaluate the corrosion inhibition performance of the synthesized polyepoxysuccinic acids.It turned out that the corrosion inhibitor which relative molecular weights is515has better corrosion inhibition performance.The corrosion inhibition efficiency of carbon steel is69.6%when its concentration is35mg/L in the test water.In addition, the corrosion inhibition efficiency is improved to76.16%by adding Zn2+and sodium gluconate as synergetic reagent.The inhibition mechanism of polyepoxysuccinic acid was also preliminarily discussed by means of analyze polarization curve and scanning electron microscopy(SEM).