| Steam condense,as a critical equipment of power plant,its high-efficient running can bring huge economic and social benefits.Condenser corrosion and scaling becomes more serious with cooling water condensation and pollution.The effects of scale inhibitor,magnetic field and acid on the scale inhibitor performance were studied by using cooling water combined with calcium carbonate precipitation method,polarization curve and dynamic simulation experiment.The results showed that when the temperature increases,the scale inhibition performance of 1-Hydroxy Ethylidene-1,1-Diphosphonic Acid and Hydrolyzed Polymaleic Anhydride decreases,the performance of 2-Phosphonobutane-1,2,4-Tricarboxylic Acid and Polyepoxysuccinic Acid increases;the efficiency of magnetic treatment scale gradually increases with the treatment time increasing,and the best efficiency was obtained at 60 min.The results of scanning electron microscope(SEM)showed that magnetic field can change the calcium carbonate structure from calcite to aragonite,which is difficult to form a hard scale.The joint processing of magnetic field with scale inhibitor improves the scale inhibitor performance.Scale and corrosion inhibition performance of stainless steel in cooling water were studied by polarization curve.The cooling water of power plant has no corrosion effect to 304 stainless steel.With concentration of the cooling water,erosion enhanced and pitting appeared at two times concentration ratio.The higher the concentration ratio of the cooling water,the lower the stainless steel pitting potential,the stronger the corrosion of the cooling water to stainless steel.The reason of the above phenomena occurred is that the precipitation of CaC03 leads to the decreasement of oxygen radical ion concentration.Acid and scale inhibitor combined treatment can reduce the concentration of scale inhibitor usage,and increase the cooling water concentration ratio.5 mg/L Scale inhibitor can make the water concentrated five times without fouling corrosion,1.5mmol/L H+ and 1 mg/L scale inhibitor can make the water concentrated six times without fouling corrosion,1.0mmol/L H+ and 2mg/L scale inhibitor can make the water concentrated six times without fouling corrosion.The fouling factors and optimal anti-fouling condition were studied by through dynamic simulation experiment.The fouling was deposited mainly in the test tube wall,the quantity was very little,so the scaling tendency cannot be simply judged according to the change of chlorine calcium consistency ratio.The fouling resistance can reflect the fouling situation of the inner test tube wall accurately.When the quantity of fouling deposition was 7.96g/m2,the fouling resistance increased by 0.1717 ×10-4m2.?/W,fouling resistance raised with the increase of fouling amount in the test tube,.The increase of scale inhibitor concentration and pH value will promote fouling deposition.Water flow rate had little effect on the fouling deposition when the rate was in the range of 1.Om/s-1.3m/s in the test tube.There are good scale inhibition effects with the combination of acid and scale inhibitor.When the flow rate is 1.3m/s in the test tube,lmg/L scale inhibitor and 8.30 pH value can make the water concentrated four times without fouling corrosion;2mg/L scale inhibitor and 8.00 pH value can make the water concentrated six times without fouling corrosion.The fouling structure and composition were analyzed by scanning electron microscope(SEM)and X-ray energy spectrum(EDS).The composition of fouling are not entirely calcium carbonate,Scale sample containing scale inhibitor for the high levels of carbon,oxygen,phosphorus.304 stainless steel has good corrosion performance in the above two schemes,and the corrosion rate was far less than the standard of 0.004 mm/a. |
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