Diesel corrosion

[Comprob]

Seems like since its inception , no one has really done anything to correct the corrosion inside diesel tanks. I can only think of what the tank itself must look like. Now homeowner heating oil tanks have this crap in them and that will eat them alive

[ZMiller]

The corrosion issues now that the causes have been determined in tanks and sumps have pretty much been resolved. Those stuck in the treatment and treadmill loop may be suffering for a little while longer. For some tanks it may be to late to address and save the tank but your probably going to see issues tapper off over the next year or two.

[bugbuster]

Funny, Zane:

I have yet to see data on:
1. Historical in UST corrosion rates or incidence of corrosion related failures (with approximate cost per incident).
2. Current, annual incidence rates (same as #1).

Without both of these, I'm scratching my head about your comment about the issue has been resolved. We have a 100 year + history of diesel fuel system corrosion but it is all anecdotal. Yes, there was a spike in the number of reported corrosion incidents a few years ago. Yes, the number of new reports per year seems to be decreasing.

I'm yet to see compelling data supporting either the perception of an increased number of corrosion events after ULSD was introduced, or more recent decrease in the number of events. Receiving few calls about an issue can simply reflect the attention span of stakeholder community members. It could be very different from the actual occurrence rate.

Cheers,
Fred

[ZMiller]

In all cases. I say ALL.

SUMPS
On sites where corrosive issues in associated and or connected sumps, on equipment or a system component connected, a tank or all tanks associated within the farm will be leaking when over pressurized. Tank(s) where saturated hydrocarbon vapors and or lower than normal PH empty tank space atmospheres are Not migrating (leaking) out of a tank into connected and or associated sumps will normally and in almost All circumstances not exhibit corrosion.

In short if you see evidence of corrosion in a sump the a tank or tanks associated at one time or another is or has been leaking.

TANKS
To follow next post

[bugbuster]

Okay, Zane.

I'm guessing that - like me - you have seen >1,000 turbine distribution manifold sumps (spill containment wells).

What percentage (of those in operation for more than a few months) have been have been corrosion-free? What percentage have had moderate to heavy corrosion covering the turbine distribution manifold?

Are you really certain that every UST with a turbine distribution manifold in the latter category is leaking?

If true, that would surprise me. I hope that if that percentage of UST systems were leaking measurably, the hew and cry would be much louder than it is - from the insurers, if not the site owners.

Again, I readily admit that my experience is biased. I have never done a biodeterioration risk survey for a client that didn't have a substantial percentage of high risk sites. However, the percentage of high-risk sites with actual fuel-leakage has been small.

Cheers,
Fred

[ZMiller]

How certain can one be when vapors are found in sumps exhibiting corrosion effects and no vapors are found in sumps not exhibiting corrosion effects.

I ask again why are hydrocarbon vapors in places where they are not supposed to be in the first place?
How do vapors just appear out of thin air or migrate from any source other than the tank(s) associated?

There seems to be an opinion that corrosion causing constituents are migrating through solid steel into spaces where they are not normally seen.

The fact is that if one sees corrosive effects in an associated sump there is or has been a leak out of saturated vapor as a corrosion effect carrier somewhere in the system.

Even the simple minded should realize and eventually come to the same conclusion that an associated tank when over pressurized is leaking vapors.

[bugbuster]

No argument here, Zane.

Except that few manifold spill containment wells are all that water-tight. Consequently, invariably, water accumulates in spill containment wells. Once there it goes through nearly daily cycles of evaporation and condensation. If hydrocarbon, ethanol, or both are part of the mix, I agree they are likely to contribute to corrosion aggressiveness. However, I don't think either (HC or ETOH) need be present for corrosion to occur. Corrosion in a >$100 billion problem outside the petroleum sector.

I'm not suggesting that HC & ETOH vapor accumulation in spill containment wells due to overpressure is not an issue. I am saying that corrosion is not dependent on vapors introduced because of overpressure issues.

Cheers,
Fred

[ZMiller]

Thought over time reformulation of fuel has occurred. Corrosion effects in sumps and overfill containment really didn't start becoming an issue until mandated installation of PV stage 1 valves on vent risers was required.

Observation of corrosion effects in tanks typically one sees attached ferrous oxides closest to conduit escape through loose fittings at the top of a fuel storage tank (IE; electrical compression through cap, fill and vent adapters, improperly torqued STP packer discharge flanges, damaged extraction gaskets, O-rings and MLLD vent connections).

Corrosion commonly starting at the top of a steel tank riser and working it's way down, a casual observer might conclude vapor and moisture presently or at some time was escaping under pressure. Further deduction as to why and where the hydrocarbon/water saturated vapors end up might be obvious as well.

We frequently see normally contained tank atmospheres escaping on test sites during bulk deliveries being made Out of Compliance when delivery drivers incorrectly connect or purposely bypass stage 1 to expedite delivery (Surveyed 24 out of 25 deliveries commonly and typically made Out of Compliance).

One might ask why it's important for a bulk fuel delivery driver to correctly configure and hook up delivery and stage 1 vapor recovery hoses?
Until bulk delivery drivers are more attentive a big part of the problem may well persist. The difference between a correct delivery dynamically balanced verses a delivery being made out of compliance is 1.5 pound of saturated vapors per 1,000 gallons of liquid delivered escaping into the surrounding environments.

[bugbuster]

Zane:

We've both been around for more than a few years. In ancient days (as many EU dispensers still are) dispensers had suction pumps within their housing. Dates are fuzzy but my recollection is that the general shift from suction pumps to submerged turbine pumps occurred in the late 80s - around the same time as the requirement for vapor recovery system installation.

I'm not disagreeing with you about the need for deliverers to be more attentive to proper delivery hook-ups. I'm saying that delivery practice is only one variable contributing to component corrosion in turbine manifold spill containment wells. I'd share photos, but have not yet gotten around to copying files from may pre-2000 Zip drives and 3.5 in floppies. I am certain that thee are more than a few photos of corroded components among my earliest retail site digital photos. Again, given that the shift to STPs coincided with installation of VRUs, I'm not sure one can easily differentiate between the effects of vapors being forced into spill containment wells due to overpressure from the effects of trapped moisture from water that entered wells as surface runoff. Absent compelling evidence to the contrary, the prudent navigator would take measures to minimize both factors. Eliminate overpressure issues during fuel deliveries and institute maintenance protocols to minimize water accumulation in spill containment wells. Note: I do not advocate draining standing water into UST!

[ZMiller]

I have given up on saving and or pointing out integrity issues due to corrosion in vessels that store fuel. In all likelihood it is as with trying to refloat the Titanic, to late to reverse the damage. There are opinioned experts all along the visible resolution path spectrum. The problem being nobody yet can see a whole picture for resolution.

The recipe for this disaster is defined by changes in storage tank Use and Regulations without consideration of system operation change dynamics or consequences.