دانلود رایگان مقاله پژوهش در علل خوردگی در سیستم تامین آب شهری

Abstract

This paper presents results of failure analysis study to characterize the corrosion damage that occurred in the water supply system in Krakow. This analysis includes: electrochemical noise, linear polarization and resistometric measurements. Water aggressiveness of four water intakes was defined using Langelier and Ryznar indices. Results from this indices did not reveal the causes of considerable corrosion losses in water systems. The corrosion rate measurements revealed that water from the one of water intakes is characterized by considerable corrosive aggression. In all studied water subsystems formation of protective layers limiting the corrosion rate was found. Overall analysis reveal the need to implement a on-line corrosion rate monitoring in the water supply system of the city of Krakow.

4. Summary

Tests of water aggression indices, which are the basis procedure for the assessment of water corrosiveness, did not reveal the causes of considerable corrosion losses in water systems in an unambiguous manner. The corrosion rate measurements performed using the resistometric method and the methods of linear polarization and electrochemical noise revealed that water from the Raba intake is characterized by considerable corrosive aggression. Sediments formed during the exposure of steel samples do not limit corrosion processes and contribute to the occurrence of a considerable corrosion rate. This requires changes in the technology of the water supply system. It is possible to change the water flow regulation to mix water from the Raba intake with other streams of water with lower corrosive aggression. In the case of the other water environments tested, formation of protective layers limiting the corrosion rate was found. Water from the Bielany intake is characterized by the lowest corrosive aggression. The results obtained indicate that it is advisable to start corrosion rate monitoring on-line in the water supply system of the city of Krakow.