Diesel corrosion

[ZMiller]

I have always presented options for adding amines to control microbial colonization in tanks to customers as part of a reasonable tank maintenance program. One problem I constantly run across in that customers don't seem to be bright enough to actually read or understand amine application instructions with a situation arriving that they do more harm than good.

The receint a few posts back though was not my composition. I was more or less just agreeing.

[bugbuster]

BTW, apropos of amines, there are two products that have both US EPA pesticide registrations (40CFR152) and fuel additive registrations (40CFR79). I have not stake in either, but these are two of the three fuel-treatment biocides that I've found to actually be effective.

[ZMiller]

Bugbuster. Are you coming to WPMA or Cal CUPA to discuss corrosion issues this year?

[bugbuster]

Sorry Zane, no.

The only conferences I attend - unless a client or the organizers sponsor my attendance are ASTM committee weeks: D02 -2; D22, E34, E35, E50 (one of 2/y), ICSHLF (Int'l Conf. on the Stability & Handling of Liquid Fuels, TAE, PEI, and STLE. That pretty well fills up my BCA-supported conference travel each year. There are many other conferences I'd love to attend - including NACE - but 7 week of conferences/y is about my limit.

[ZMiller]

Hi Zane - always good talking to you.

I thought that the PEI forum would be interested in an email discussion I’m having with the STI and industry fuel experts on the corrosion mechanism and corrosion control in stored fuel. STI published the detailed article in Tank Talk https://www.steeltank.com/Publications/ ... fault.aspx

There is also a LinkedIn discussion group, just started: https://www.linkedin.com/feed/update/ur ... 162436609/
Here is a brief summary of the corrosion mechanism. Read the article for details.

Note for corrosion control I discuss SAE J1488_201010 filtration as I’m familiar with it, but Nitrogen Blanketing also seems to be a viable alternative.

Summary: the corrosion mechanism is very simple, and has 2 steps:

1 - water permanently moves into fuel column. How? Biofuels are polar, as is water, so water and biofuels form a hydrogen bond; this bonded emulsified water stays permanently attached to the biofuel molecule in the fuel column.

2 - there is a great increase in the number of microbes; microbes now have the water they need to survive in the fuel column, away from the traditional place they live, the thin water fuel interface. More microbes produced + more acids produced = corrosion crisis.

The corrosion control is also very simple, fuel filtration of biodiesel blends (lower IFT), using a new generation of filters that can break the hydrogen bonds, as tested against the filtration industry standard SAE J1488_201010, with a minimum efficiency rating of 92%.

If this corrosion mechanism, and control, is so simple, why has this not been recognized before? What is new, and what factors are not being recognized?

The mantra of every fuel maintenance program is dry the fuel, but then goes on to recommend testing for water content by looking for water bottoms, or a “clear and bright” test. There is absolutely no recognition that water is permanently bonded into the fuel column, or that the only way to detect bonded emulsified water is by an inexpensive Karl Fisher titration test, or that efficient SAE J1488_201010 filtration can break the hydrogen bonds and remove the water.

I look forward to your comments.

Thank you.

Pat

Pat Smyth MBA
President
Octane Systems Inc.
patsmyth@octanesystemsinc.com
613-794-6090
www.octanesystemsinc.com

[ZMiller]

I see the same issues with water in the fuel column of ethanol blended gasoline. Typically a heavy ethanol/water phase at the bottom can be removed but then temperature clouding sensitive water is still bonded in the remaining ethanol in the fuel column. Getting water out of the fuel column after the heavy phase has been removed requires lowering the temperature in the fuel column and freezing the water entrained (bonded). That one extra bonding oxygen molecule is the bitch sort of speak. Chilling the fuel separates the remaining water from the fuel but it drags the rest of the attached oxygenating ethanol with it and you end up with straight base blend stock R or C.

I'm now wondering if the cloudy diesel after water intrusion can be frozen out.

[mike10]

Most everyone is still got their heads buried in the sand on this issue. Other countries don't have this issue.

[CherokeeUST]

Ethanol is not the cause of corrosion???

http://digital.peijournal.org/peijourna ... &u1=friend

[bugbuster]

We (members of the CRC Fuel Corrosivity Panel) are waiting with baited breath for the final report based on a 128 microcosm (1L jars containing various combinations of fuel, water, and additives/contaminants) study designed to identify the most likely factors contributing to corrosion in diesel UST. Once we have approved the final report, I'll be able to share its findings. For now, I can share the conditions:

• Fuel grade - LSD & ULSD

• Ethanol (+/-)

• Glycol (+/-)

• FAME (biodiesel) (+/-)

• Water (+/-)

• Cold flow Improver (+/-)

• Monoacid lubricity additive (+/-)

• Corrosion inhibitor (+/-)

• Conductivity additive (+/-)

• Microbes - intentional inoculum developed from contaminated ULSD bottoms-water samples and unintentional inoculum - microbes present in the test fuels

• FRP - fiber-reinforced polymer - coupons (+/-)

Each microcosm had four corrosion coupons suspended in it to ensure that there was fuel, water, and vapor (head space) exposure.
The microcosms ran for 12 weeks. By the end of the 4th week there was visible corrosion in some microcosms. Stay tuned. I expect that we'll have a paperer about the study in a future issue of PEI Journal.
The article arguing that ethanol is not a contributing factor has a number of misstatements. Several published research papers have demonstrated without a doubt that sulfur content did and does not impact fuel biodeterioration. Anyone familiar with the >100 year history of fuel biodeterioration knows this. Microbiologically influenced corrosion (MIC) has been an issue since the earliest days of diesel fuel use. There's no way to prove it, but I suspect that the spike in reports of fuel system corrosion reflected increased awareness rather than increased occurrence. Two industry surveys - 2012 & 2016 - discovered more severe corrosion in UST systems at supposedly problem-free, control sites, than at sites whose operators had reported problems. In the 2016, EPA-sponsored work, 82% of sites thought to have no problems actually had moderate to severe corrosion. Bottom line: reported incidence rates have little relationship to actual incidence. This disconnect is common in public health. Typically the "discovery" of a "new" disease actually indicates that the disease has finally caught the attention of clinicians and epidemiologists. It rarely indicates that a new microbe has suddenly started to make people sick. There are exceptions, but they are another story...

[bugbuster]

Cherokee:

My short answer about dismissing ethanol as a potential factor contributing to corrosion in ULSD systems is to hold off on that. Ethanol can be converted to acetic acid either biologically (by microbes) or abiotically (chemical reactions between ethanol and available oxygen).