Study On Effect Of Reclaimed Water Reuse On Corrosion And Scaling In Circulation Cooling Water

Reusing the reclaimed municipal wastewater in the industrial recirculation cooling water system is one of the effective ways to eliminate the water resource shortage. A study was performed to investigate into the effect of reclaimed water on corrosion and scaling in cooling water system.Test was made up of three stages, first stage study the effect of influence factor in reclaimed water on corrosion and scaling Through the static hanging slice test and calcium carbonate aggradation test, when they existed separately; second stage designed orthogonal test on corrosion and scaling through the result of first stage to study effect on corrosion and scaling of influence factor cooperate with each other, and discovered the factor which was controlled firstly; third stage study the change current of influence factor, effect on heat exchange capability of velocity of flow in cooling water system and the composition of fouling through dynamic simulation test.Result of corrosion test indicated that NH₄⁺-N was the most important factor on carbon steel corrosion. Effect on corrosion of Cl^- and SO₄^2- were similar with each other, but SO₄^2- can make bore corrosion. PO₄^3-, NO₂^--N and a small quantity of Ca²⁺ and HCO3- could reduce corrosion velocity.Result of fouling test indicated that Ca²⁺ and HCO3- were the mainly factors of fouling. NH₄⁺-N and PO₄^3- were the most important influence factors on fouling, and NH₄⁺-N could control the fouling when PO₄^3- accelerate it. Temperature's effect was smaller than NH₄⁺-N and PO₄^3-, and the effect was larger when it beyond 600C. Effect of organic compounds and SO₄^2- could be ignored.Result of dynamic simulation test indicated that concentration of cooling water could cumulate Cl- clearly. PO₄^3-could synthesize NaFePO4 with Fe²⁺ to make concentration of them descend in anaphase of test. Concentration of NO₂^--N in cooling water was mainly controlled by concentration of dissolved oxygen and makeup water. Fouling capacity of Ca²⁺was lager than Mg²⁺. Concentration of NH₄⁺-N was decreased because of nitrification.Heat exchange capacity of cooling water was mainly controlled by concentration of dissolved oxygen and temperature of cooling water when...