AWWA ACE69099

This powerpoint presentation begins by providing a brief overview of non-uniform copper corrosion and flow electrification. Laboratory scale studies were done to investigate theeffects of flowelectrification andpitting on a series ofcopper piping. Conclusions on the effects of flow rate onflow electrification indicate the following:flow electrification was observed at all velocitiestested between 0.9-6.6 fps and was worst at 2.8 fps;an optimally "bad" flowrate may exist resulting inhigher currents between first and last pipe tocontact flow; and, pitting might still occur at no flow and at highflow, but the rate may be reduced. The impacts of sulfide on flow electrification were examined to determine theeffects of sulfideon flowelectrification. Sulfide conclusions indicate that:the presence of sulfides made the portion of pipe that firstcontacts flow cathodic relative to later sections; and,flow electrification effects were highest when the sulfideconcentration was highest. The effects of inhibitors on flow electrificationin a recirculation rig were examinedto study the effects of various inhibitors on a known pittingwater. Presentation conclusions indicate the following: observed flow electrification in numerousexperiments; the magnitude of the flow electrification increasedwith higher Cl₂ and varied with flow rate; zinc orthophosphate had the largest positive impacton electrochemical measures of pitting;the presence of sulfides made the portion of pipe thatfirst contacts flow cathodic relative to downstreamsections; and,the magnitude of flow electrification and its sign dependon the water. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

32

File Size:

1 file , 1.6 MB