Clarification on Corrosion Process Please
Clarification on Corrosion Process Please
(OP)
Some guidence would be great on this one.
I have two brine waste streams (2500 and 8400 gpm pH about 8.4, 30% TDS, Temp 65C, Alkalinity 350 ppm as CaCO3, though Alk could be higer) to be pumped below ground in carbon steel pipe. Life of pipe about 20-30 years
From these streams I intend to remove CO2 and O2 possibly with a Vac Degasifier coupled supported with a steam feed.
My first Question - What levels do CO2 need to be reduced to significantly reduce potential corrosion? I know for boilers it gets reduced to the ppb level but that seems excessive for this application.
My second question is regarding the corrision mechanics or chemistry involved.
Co2 in water converts to carbonic acid then to bicarbonate then to Carbonate as the solution pH increases. According to the charts I've seen carbon acid does not exist above pH of 8.4 or so, but as bicarbonate and carbonate. So does that mean corrosion is not a problem in this stream because of the high pH (scaling maybe a problem) and it doesn't need to be removed? Or does the stream need to be pH adjusted before the degasifier to free the CO2 for some reason that escapes me?
Thanks
I have two brine waste streams (2500 and 8400 gpm pH about 8.4, 30% TDS, Temp 65C, Alkalinity 350 ppm as CaCO3, though Alk could be higer) to be pumped below ground in carbon steel pipe. Life of pipe about 20-30 years
From these streams I intend to remove CO2 and O2 possibly with a Vac Degasifier coupled supported with a steam feed.
My first Question - What levels do CO2 need to be reduced to significantly reduce potential corrosion? I know for boilers it gets reduced to the ppb level but that seems excessive for this application.
My second question is regarding the corrision mechanics or chemistry involved.
Co2 in water converts to carbonic acid then to bicarbonate then to Carbonate as the solution pH increases. According to the charts I've seen carbon acid does not exist above pH of 8.4 or so, but as bicarbonate and carbonate. So does that mean corrosion is not a problem in this stream because of the high pH (scaling maybe a problem) and it doesn't need to be removed? Or does the stream need to be pH adjusted before the degasifier to free the CO2 for some reason that escapes me?
Thanks





RE: Clarification on Corrosion Process Please
PS: I know nothing about degasification, boiler, etc.
RE: Clarification on Corrosion Process Please
RE: Clarification on Corrosion Process Please
I agree with focusing on oxygen removal.
A quick one for you. What meathod do you use?
I'm currently looking at chemical scavaging (expensive do to volume of chemical needed per year), vac degasing using either a steam source or negative suction pumps to draw off the oxygen, and the last air scubber but not hopefull with it as only brings down oxygen to equilibrium level.
What level do you remove O2 down to?
Thanks
RE: Clarification on Corrosion Process Please
One question is: The line is already installed (Carbon Steel) or you have to select the material? Maybe a different material selction would be the best solution.
S.
http://www.corrosionist.com
RE: Clarification on Corrosion Process Please