Elektrochemiczne badania korozyjne w instalacjach geotermalnych

Abstract

Electrochemical investigation of corrosion in geothermal plants.A b s t r a c t. Electrochemical investigation were carried out in the two geothermal plants exploiting low and high mineralizated water (Geotermia Podhalańska and Geotermia Stargard). Investigation embraces monitoring of steels and alloys rate of corrosion based on linear polarisation resistance method (LPR), electrochemical polarisation measurements using linear sweep voltammetry (LSV) as well as technique of electrochemical impedance spectroscopy (EIS). Electrochemical properties of water (pH and Eh) were also measured. On the basis of LPR method the influence of chromium on corrosion rate was established. It was also determinated that rate of corrosion on the level of 0.05 mm/year is reached when the Cr content in steel is higher than 5%. LSV mesasurement indicated slowdown of the anodic dissolution rate and increase of breakdown potential as effect of enrichment of the corrosion product layer in chromium. Comparision of various types of the electrochemical investigations indicates that salination of the geothermal water is minor factor in the corrosion of steels.