Diesel corrosion

[ZMiller]

We have another nightmare beginning to effect containment integrity.

Compatibility of the tank is one issue. I'm thinking we are missing or ignoring a more serious integrity issue of internal velocity corrosion of pressurized product delivery piping. Both diesel and lighter hydrocarbon fuels. We are seeing imminent product line failure conditions with surface losses around 20ml per year. We might want to review further study data.

[bugbuster]

Interesting, Zane.

How are you defining pressurized piping (i.e., what pressures are you talking about?)?

Product delivery to retail and fleet UST? I've only seen gravity flow deliveries, except for home heating oil delivery where product is often pumped from the truck to the tank (AST or UST). The flow rates used in these systems wouldn't be likely to cause either cavitation or erosion corrosion.

Better fuel polishing systems used to clean retail/fleet UST can move product a high pressures and velocities, but I would be surprised if the short exposures to such flow would affect the fuel system - especially since most of the surfaces with which the recirculating uel comes nto contact is part of the cleaning rig, not the system being cleaned. I'd love to read more details.

Cheers,
Fred

[ZMiller]

I'm glad you asked.

What would be considered normal fuel dispensing in a typical retail fueling facility. Though 20 mils per year doesn't sound like a lot, over time it all kind of adds up to a frightening amount of surface loss.

[bugbuster]

Were are you seeing this erosion wear? UST floor under fill line? Somewhere else?

[ZMiller]

Internally in fiberglass, flexible and flex guard braided piping Elbows, T's and swiveling crimps. Factory machined surfaces not adequately hard treated and pressed fittings and valve seating's in older pump heads. Meter calibrated surfaces. Slow flow Control valves and most hanging hardware components particularly dispenser up stream jumper hoses of break fittings. Shear valve platforms and shear valve platform trip shaft pivot points.

Where else I suspect but afraid to look.

[bugbuster]

Again, quite interesting, Zane.

Some years ago, I had an opportunity to do autopsies on about 100 dispensers - pumps, valves, and filters.

Although I observed some internal surface corrosion, and elastomer deterioration, I didn't see anything that looked like erosion wear. Seems like this is a design and materials improvement opportunity for the OEMs. I don't believe that fuel chemistry would have much impact of erosion corrosion. As I understand it - speaking as a microbiologist who generally gets involved only with MIC issues on the corrosion front - this is all about fluid dynamics - turbulent flow and cavitation. I wonder about the extent to which new equipment was designed without adequate attention to these two factors...

[ZMiller]

Issue updates coming soon.

[bugbuster]

Heart be still...

[CherokeeUST]

What do you think about using FRP risers to avoid corrosion?

I had a site many moons ago in Okmulgee, OK. that had an FRP riser for the fill. The riser cracked and allowed fuel to enter the environment. It became a pretty big release. Is that not a risk of these?

[bugbuster]

Several years ago, Jeff Leiter, coincidently PEI's and the Fiberglass Tank and Pipe Institute's corporate counsel sent me a cease and desist regarding the opinions I had published about FRP biodeterioration risks. Respecting Mr. Leiter's letter, I'll decline to comment.

Cheers,
Fred