Study On Application And Performance Of Scale Inhibitor In Circulating Water System Of Air Conditioning In Textile Mills

Through the sampling analysis of the air conditioning circulating water in Xianyang textile mill,it is found that the water quality has the problem of high hardness and corrosion.In this study,a terpolymer scale inhibitor having various functional groups was synthesized by aqueous solution free radical polymerization method.Three monomers are itaconic acid?IA?,sodium allyl sulfonate?SAS?,and hydroxyethyl methacrylate?HEMA?,the initiator used in this reaction is ammonium persulfate,and the tert-butanol as molecular weight regulator.The optimal synthesis conditions of the terpolymer were determined by orthogonal comparison experiments.The monomer ratio?IA:SAS:HEMA?=3.5:1.0:0.8,the amount of initiator and the amount of t-butanol accounted for 11%and10%of the total mass of the monomer,reaction temperature was 90?,reaction time for2h,the scale inhibition rate of the synthesized terpolymer scale inhibitor was 98.76%,and the solid content was 13.25%.The static experiment results show that the copolymer has good scale inhibition effect on CaCO₃ and CaSO₄ in both summer and winter temperatures.The scale inhibition rate of CaCO₃ is 98.25%,the scale inhibition rate of CaSO₄ is 80.05%,when the copolymer concentration is 5 mg/L,the temperature is 25?,the water bath time is 10h.Compared with the commercially available scale inhibitor polyaspartic acid under the same water quality conditions,the effect is obviously better than polyaspartic acid,so it is more suitable for the air conditioning circulating water system of textile mills.The structure of gel chromatography showed that the molecular weight distribution of the copolymer is basically normal distribution and belongs to a polymer with narrow molecular weight distribution.The infrared spectrum results shows that the copolymer contains functional groups such as carboxyl group,hydroxyl group,sulfonic acid group and ester group,the functional groups synergistically synergistically effect on the copolymer.The scanning electron micrographs show that the copolymer can change the arrangement of CaCO₃ and CaSO₄ crystals in the nucleation process,which makes the crystal morphology change,it has good scale inhibition and dispersion properties for CaCO₃ and CaSO₄.The corrosion inhibition performance of the copolymer and zinc salt compound and the effect of pH on the corrosion inhibition performance were studied by the rotating coupon method.The results show that the copolymer has a good synergistic effect with the zinc salt,and is suitable for the alkaline environment.When the zinc ions(Zn²⁺)dosage is3 mg/L,the copolymer has the best compounding effect and its corrosion inhibition rate is over 90%.Moreover,when the amount of copolymer is small,the addition of zinc ions(Zn²⁺)significantly improves the corrosion inhibition performance,and the biodegradation rate of the copolymer on the 28th day reaches the theoretical value of 60%,which satisfies the conditions of the biodegradable scale inhibitor.Using the saturation index?L?of Langelier and the stability index?R?of Rezner,it is concluded that the hardness of the circulating water of the air conditioner has a relatively large tendency to scale.The test showed that the copolymer has good scale inhibition performance,effectively alleviated the problem of scaling and corrosion of the system,when this copolymer was applied in the air conditioning circulating water system of the textile mill.At last,it is verifying that the copolymer can be applied to the open air conditioning circulating water system of the textile mills.This paper has a total of 41 pictures,12 charts and 87 references.