Could you please share with me your thoughts of introducing a dematerialized water into a carbon steel piping and vessels/tanks. Your feed back is highly required
Dematerialiazed water... lol, you're in the Star trek future Drsmk.
I work in a petrochem plant with four 60tonne/hr package boilers. We have a demin plant with a dearator. The demin water piping and demin water storages are lined, but the piping from the dearator to the boilers is plain carbon steel (there's a downstream oxygen scavenger addition step as well reducing dissolved oxygen down to low ppb).
We have no unusual corrosion in the boiler feedwater part of the system and the lined pipe (rubber lined) and lined storage (vinyl ester tank lining IIRC) keep corrosion issues at bay in the Demin part of the system.
Hope that helps.
Cheers
Rob
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"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."
rmw: I really don't like the "hungry fluid" bit. That kind of statement leads to an incorrect understanding of what is going on.
It is correct to say that demin water is easily contaminated with metallic ions unless correct materials are selected. But the concern over the contamination depend entirely on why the water was demineralized in the first place.
Demin water is corrosive to carbon steel and copper/brass etc. when it's oxygenated- potentially severely so depending on numerous factors including the degree of demineralization, temperature, flowing conditions and on the amount of dissolved oxygen present.
As robsalv points out, when demin water is scrupulously deoxygenated it's not particularly corrosive to either carbon steel or copper.
I'm looking at protecting a coated carbon steel pipe that carries seawater. In addition to the inside coating, the design calls for sacrificial anodes placed strategically on the inside, and an impressed current cathodic protection system on the outside for the buried segment of the pipeline.
Is there any potential that the outside impressed current system will impeded or affect the inside galvanic protection system?
Anodes on the inside will add more ions to the water.
In most cases you don't need them. If the water conductivity is low enough then even small coating defects will not cause problems.
sorry about the mixed message.
Many sacrificial anodes are mounted with a lead to ground. You can lift this lead and measure the current. Combine this with a reference cell to measure the potential and you can make sure that the anode is still working.
