The contribution of the organic pollutants from the feedwater of the steam generator to the corrosion processes and deposits - operation problems

The presence of the ionic and nonionic organic matter in the boiler feed circuit influences upon its reliable operation. The organic matter can alter the feed water and process steam quality in terms of their electrical conductivity increase and of their pH reduction, this being responsible for corrosion development and deposit formation. The organic matter presence is due to the leakage from the surface water demineralizate in plants that was chemically polluted with organic products. The investigations conducted on a high power steam generator (type TGM 84) and on a 50 MW turbine (type DSL) included: water and steam chemical control, identification and quantitative dosing of organic matter on each thermal step: feed water, steam, superheated steam, demineralizate, through gas chromatography and mass spectrometry (GC-GC/MS), metallographic examination of the pipes material from the vaporizer and the stream superheater, chemical analysis of the deposits, and examination of the IP and LP parts of the turbine.