| Corrosion and Scaling always happen to heat exchangers in circulating cooling water systems. Therefor, People have been looking for different monitoring methods to predict the change of corrosion and scaling So as to adopt respective measures to diminish the loss by corrosion and scaling. The existent monitoring methods have some shortages more or less, neither can simulate the condition of heat transfer nor can simulate the hydromechanical condition. The present thesis studies the monitoring method for corrosion rate and fouling resistance .A monitoring system for corrosion and scaling of circulating cooling water has been developed. This system includes the following properties:1. The equipment can simulate the operation condition of cooling water flowing and heat transfering .2. The corrosion potential is traced and compensated by a computer so that the effect of the draft of corrosion potential is eliminated.3. The effect of IR drop is offset by current interruption through a electronic switch.4. The fouling resistance and corrosion rate are monitored simultaneously. The measurment of fouling resistance is realized by contineous testing of the temperature of the tube wall and water of the system .The corrosion rate is measured by means of linear polarization for a three electrode system. The constant of linear polarization equation is supplied by weak polarization measurement. Besides, the weak polarization measurement also computes the corrosion current through iteration and regress.A whole set of software(FRCR) has been developed. It has the function of automatical controlling, measuring, sampling and data processing. The results show that the present monitoring system can sensitively reflects the contineous change of corrosion rate and fouling resistance. |
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