Doesn't Steel contain Manganese?

[RWebb]

https://scitechdaily.com/microbiologists-discover-bacteria-that-feed-on-metal-ending-a-century-long-search/

[RWebb]

that high strength steel is fragile...

[john70t]

Bacterial eating metal. That's pretty cool. Thy belong besides the invincible Tardigrades, the immortal jellyfish, and the deep ocean sulfur plume residents.

[unclebilly]

Yup, I wrote 2 technical papers on this back in 2014 and 2015... the 2015 paper even made its way into the JPT...

https://www.tricanwellservice.com/news/trican-leads-preventing-microbial-influenced-corrosion

https://www.tricanwellservice.com/sites/default/files/pdf/1488_IPTC_TechnicalPaper_18032_0.pdf

https://www.tricanwellservice.com/sites/default/files/pdf/1487_SPE_TechnicalPaper_173658_0.pdf

[RWebb]

"a localized corrosive environment"

agh

[unclebilly]

So here’s the 2 bit explanation of all of this...

Microbes exist in aqueous environments under conditions that they like. No surprise here.

There are 2 types of bacteria, sessile and planktonic. Planktonic bacteria move around in water whereas sessile bacteria typically attach to a surface and form a community of various types of bacteria in a biofilm.

The biofilm is comprised of lots of stuff and we all have direct experience with biofilms (the tarter on your teeth is a biofilm, so is the slippery stuff around the surface of a swimming pool). Let that pool example sink in... think of how much chlorine is in a pool, yet that colony of bacteria is still able to thrive.

The bacteria secrete sugars and the gooey slime that protects the colony. This also allow anaerobic bacteria to live in a biofilm that is generally exposed to air. Generally layers within the biofilm support one another so the community can thrive.

When conditions (temperature, pressure, presence of oxygen, presence of nutrients) change, the bacteria present either go dormant or die and are eaten by other bacteria. This is called a population shift and happens nearly every time you take a sample of planktonic bacteria.

One phenomenon under which bacteria eat metal (microbial influenced corrosion) is by sulphur reducing bacteria (SRBs) which reside in the inner layer of the biofilm. These species of bacteria create microscopic levels of bacteria that when combined with water result in high contractions of hydrogen sulfide and sulfuric acid right at the surface of the steel. Other species of bacteria within the biofilm are able to metabolize metal ions. There are several types of bacteria responsible for MIC such as iron oxidizing bacteria (IOBs), thiosulfate reducing bacteria (TSBs), and others. We found examples of each type in our metagenomic (DNA) testing.

Further, bacteria complete electrochemical half cells within the grain structure of the steel. For instance there is a slight electrochemical potential between banite and austenite which are both present in heat affected zones resulting from a weld. This is why welds are more prone to microbial influenced corrosion than the base metal.

I could go on and on and on about this but if anyone is interested, I will send you a copy of my papers. It’s cool that I lead the team that first cracked this weird corrosion we were finding and now there is a whole industry around preventing MIC in oilfield equipment.

The bottom line is that the bacteria that is causing this corrosion is present in produced water from shale wells. Shale is a source rock which means that the shale is where the hydrocarbon came from. Hydrocarbons result from bacteria breaking down organisms such as plants and animals. As pressures and temperatures and the nutrient levels changed, tHe bacteria went dormant. When we frac these wells, we introduce water, we cool down the rock, we add nutrients (polyacrylomide and guar) and then when we put the well on production,we reduce the pressure. This enables a subset of the bacteria species to come out of dormancy. Once the water is flowed to surface and separated from the hydrocarbons, the water sits in flow back ponds in the warm Texas sun and the bacteria colonies thrive. When we reuse this water for frac’ing other wells we contaminate the pumping equipment and new wellbores with damage causing bacteria.

[RWebb]

[] , not contractions


Does the process of welding cause those changes, thereby resulting in an eletrochemical half-cell?


How do we kill them, before they kill our cars?

[unclebilly]

Mechanical removal of the biofilm is the first step, then keep it dry.

Most biocides are not human friendly so you don’t want to use this.

Bleach and other oxidizers that are effective at killing planktonic bacteria are generally corrosive to steel so their use can make corrosion worse.

What we found worked was mechanical removal followed by bleach followed by a quat / thps biocide combination followed by corrosion inhibitor. A nitrogen blanket for storage also showed significant benefit.

[oldE]

Thanks for the excellent synopsys, UncleBilly.

When folks come through the Tidal Power Interpretive Centre, I keep telling them, "There's no such thing as a free lunch. Everything you do has a cost. If you're lucky, you know all the costs up front. Usually though, you find out a lot you didn't know much later."

Best
Les

[Sooner or later]

Good stuff, Uncle.

[Norm K]

Originally Posted by RWebb

"a localized corrosive environment"

aka, PARF?

_

[GH85Carrera]

It is truly amazing the environments that bacteria can not just survive, but thrive. Eating metal is not too hard to imagine. If there is water there is life on this planet.

We simply can't survive without the good bacteria. And keeping the bad bacteria in control is a near impossible task.

The only way to protect metal for true long term is to keep it away from moisture.

[vash]

i dont know about steel, but bananas have it.

[nota]

as I have said

RUST IS ALIVE

that is why it grows and has to be totally removed or it comes back
and processes like galvanizing create a toxic environment to inhibit rust

[unclebilly]

Galvanizing won’t prevent MIC. Copper and Silver do inhibit biofilm development.

[sammyg2]

I'm studying a lot of this stuff so I know it, ya know .... like Chinch bugs. ya know ...
Manganese. most people don't even know what that is.
Nitrogen. Ya know