Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: Julian on May 22, 2015, 09:28:16 PM
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Thought Id' start a new thread to hopefully start this idea of using the wiki to collate collaborative tests done by members and detail experimental processes they may be trying.
This idea originated from this thread ... http://www.biopowered.co.uk/forum/index.php/topic,2518.15/topicseen.html (http://www.biopowered.co.uk/forum/index.php/topic,2518.15/topicseen.html)
Page is here ... http://www.biopowered.co.uk/wiki/Biodiesel_and_oil_oxidisation_collaborative_trial (http://www.biopowered.co.uk/wiki/Biodiesel_and_oil_oxidisation_collaborative_trial)
I've started filling in the table and will complete it tomorrow once I've set some bio aside in a saucer.
I really hope others will join in.
Can any one suggest the frequency needed between observations?
Welcome any comments good or bad!
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Does Weekly sound good?
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We can try that but I was thinking we may need to look at months.
I'll make it weekly and we can see how it goes.
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I will put some by. Are you using bio after settling or straight from the processor?
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Nick may have a better idea than me ... it was his idea, but I'd suggest people use whatever they consider their finished bio.
Perhaps brief notes as t the production methods and type of washing if any would be helpful ... I'll add to the wiki page.
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We know that certain metals promote oxidation, copper in particular and iron to a lesser extent. I think it would be interesting to include some samples that contain copper fillings or iron fillings. This would better simulate conditions in our fuel system that have many metal parts.
Nick
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We know that certain metals promote oxidation, copper in particular and iron to a lesser extent. I think it would be interesting to include some samples that contain copper fillings or iron fillings. This would better simulate conditions in our fuel system that have many metal parts.
Nick
Sounds like an idea. It might be easier for people to obtain small scraps rather than filings although the surface area wouldn't be as great. Feel free to modify the page to include this or would;d you like me to do it?
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Just updated the wiki page with a photo of my efforts plus some text.
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Great start Julian. I think we could also investigate feedstock as it looks like iodine value is a factor. I think all my oil these day is GM Soya but it would be good to include palm oil and rapeseed (& sunflower?) in the trials. Palm oil has the lowest iodine value and so I think we would expect this to be less susceptible to oxidation.
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Yes, it may be a good start but it's a little futile if I'm the only one participating!
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I have three jars on the go - one plain bio, one with copper wire and one with iron wire. Nothing to report so far.
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I was going to use beakers, but thought that may effect the level of oxygen at the surface ... I believe nitrogen is slightly heavier than oxygen. Don't know it that makes any sense but that was my Muppet level reasoning?
Similarly having the samples outside I thought might allow better air movement over the surface.
Copper sample is already showing signs of "green" around the wire.
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Just added comments for the last two weeks.
Nick you deleted a post. I agreed with what you said about the science, but I think exercises like this are valuable in the future if lots of people get involved.
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Just added comments for the last two weeks.
Nick you deleted a post. I agreed with what you said about the science, but I think exercises like this are valuable in the future if lots of people get involved.
Yes, I wrote it last night when I was wound up (don't ask) and dog tired. After sleeping on it, I thought it was unduly critical so I removed it. I fully agree, what we're doing is a useful exercise and should hopefully give us some ideas for future, more scientific testing :)
Cheers
Nick
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Just added comments for this week.
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I will add comments soon, most noticeable change with mine is the increase in viscosity, one with steel has rusty coloured bio around it. It's got to the piont where the petri dish can virtually be turned upside down without anything dripping out.
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Likewise - the most noticeable thing is the increase in viscosity.
Perhaps because the metal in two of my samples is completely submerged, the discolouration is less than I was expecting. Also, no hint yet of the acid smell I sometime get when opening an "empty" cubie that has held a few ml of bio for some weeks.
Nick
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Also, no hint yet of the acid smell I sometime get when opening an "empty" cubie that has held a few ml of bio for some weeks.
That's interesting, I've experienced exactly the same thing, never really thought about it though (it's always been from a cubie sat in the sun with a splash of bio at the bottom). I always assumed the smell was from the plastic/previous chemical residue.
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And me, I would't call it an acid smell but it's sharp to the nose when you open the cubie top. All the cubies that I use for bio have only had new oil in them. I then wash them out with bio before using them for same.
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Just added another update ... getting quite colourful now.
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The wiki page seem to have rather died a death, but I've still got my samples sitting outside under cover.
This is how they looked in July last year ...
(http://www.biopowered.co.uk/w/images/thumb/c/c6/Samples.JPG/500px-Samples.JPG)
The colours have deepened dramatically, but the viscosity of each is interesting.
In an overnight ambient of -1°C the plain bio sample is a lot more viscous but will still pour, the iron sample is solid and very firm, but the copper sample is only a little more viscous than at the start.
Bio in my storage tank below the samples looks quite normal.
The chemistry is beyond me but the marked difference between the three is quite puzzling.
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Sorry, Julian.
I had almost forgot I still had the samples on my bench. The one with the piece of steel immersed in it looks like rust leaching from the metal. Both samples have polymerised in that both dishes can be turned upside down without anything dripping out. My samples have been kept inside the bio room and therefore generally warmer than outside.
If we were expecting oxidation to take place in that the bio would become dark coloured then personally I would say that the oxidation has not taken place.
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I wasn't pointing a finger, Dave!
The page seemed like a good idea when it was suggested, but few participated ... shame as this sort of thing could collect a good spread of information.
I still want to know why my iron sample has gone solid and the copper sample is still runny when both are the same bio.
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I still want to know why my iron sample has gone solid and the copper sample is still runny when both are the same bio.
Could it be them Rusticle bacteria affecting the bio?
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I still want to know why my iron sample has gone solid and the copper sample is still runny when both are the same bio.
Could it be them Rusticle bacteria affecting the bio?
It's comforting to know there's always an expert on hand to offer advise.
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It's comforting to know there's always an expert on hand to offer advise.
Surely you've seen what the iron eating bacteria have done to the Titanic, and gawd knows what they poo out.
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I've seen what bacteria can do to injectors springs on a large generator on an RAF "early warning system".
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I still want to know why my iron sample has gone solid and the copper sample is still runny when both are the same bio.
Could it be that whatever is causing some sort of reaction between the copper and the bio is stopping polymerisation.
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Given that the samples are open to the atmosphere and therefore humidty it could be that the samples with steel present are showing the effect of more rapid corrosion. Once steel (primarily iron) starts to rust the crystal structure is such that it opens up more area for further corrsion, whereas in copper I believe the crystal structure of the copper oxide is more akin to that of black iron oxide in that it is larger than the underlying metal and effectively seals the metal in a protective envelope.
Iron complexes may be easier to form than copper ones due to the larger surface area of the rust particles. The unsaturated double bonds in the bio could then complex more easily with the iron, or form polymers more easily. Either way this formation of larger molecule would result in higher melting points or the whole sample going solid more easily.
One factor I could not see taken into account was light. If the samples were in direct sunlight then free radical formation would be much more likely leading to rapid polymerisation. I would expect samples in the dark to polymerise more slowly.
Has anyone looked at how to measure whether there has been increased oxidation, or just polymerisation taking place?
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Thanks for that, Paul ... I'm afraid most of it went over my head, but a little computed!
The iron sample is cast iron. The samples are not in direct sunlight, but have every opportunity to absorb moisture from the atmosphere.
The thing I found strange was that the bio sample was more viscous than the copper sample ... as if something from the copper contamination was inhibiting gelling.
At current temperatures (circa 10 - 11°C) all samples are liquid to various degrees.
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Julian
It does not surprise me that the copper one is much closer to the normal bio. Copper will form a coating as I explained and that will limit the amount of bio that can complex with it. Anything that does dissolve in the bio is likely to supress its freezing point (well gel point in this case) think of how salt water freezes at a lower temp than fresh, or bio with petrol in gels at a lower temp than fresh (which I had a better example for bio!)
Another issue that is dfficult to measure like this is the effect of any bugs landing on the samples. In the case of simple Bio, these bugs can probably grow slowly, in the case of copper being present they would probably be unable to grow, with iron present they are quite likely to grow. I have no idea whether any of the samples will have a significant amount of biological activity or not, but just a theory.
How do the bio and copper samples compare with bio that has been kept free of oxygen and light?
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See, an' you thought I was talking out me rear end when I mentioned bacteria.
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I didn't keep a sample from the same batch, but my storage tank is in the same place, is HDPE so cuts out a large portion of ambient light and is sealed save for a small vent and the bio in that is fine, but that's not really a fair comparison.
There's no visible signs of biological activity but I guess that doesn't mean it's not there.
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If the bio really does oxidise, I would have thought that the colour would deepen. With my samples other than the one with the steel (where the bio is rusty) the only thing that has happened is that they are now really thick ie polymerised.
They have been on the bench in the bio room in petri dishes so partially open to air and have been subjected to between -5 and around +28degs.
There are reports on infopop of people using 2 year oil bio without problems so I don't think we need to worry.
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There's no visible signs of biological activity.
I'm not surprised you can't see any bugs, they're only about 4.5u long.
Unless of course you've been to Specsavers.
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Yesterday I opened an old 25l drum with a thin layer of biodiesel on the bottom. It was like treacle, and had the bitter smell I associate with oxidised biodiesel. Clearly not much air exposure is required for this (whatever "this" is) to happen. It was still clear light yellow, however, not red/orange in colour.
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The bitter smell (I would call it acidic) is going to be low molecular weight carboxylic acids.... eg formic, acetic
I will post some pics of my samples... the most striking observation is how the steel has reacted. I wonder if some of the brown stuff we find in our fuel filters are in fact iron complexes rather than glyc?
Nick
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I get brown gunk in the Disco filter. The only steel part of the fuel system is the pick-up pipe in the tank, but that has a heavy zinc or similar coating and shows no sign of corrosion.
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http://biodiesel.infopop.cc/eve/forums/a/tpc/f/419605551/m/1327038083?r=1327038083#1327038083
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Yup, that's similar to what I get in the storage tanks and car filter ... nothing like that bad though.
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I thought Wesleys' last post was interesting re fatty acids with double bonds causing auto-oxidation.
Julian, I was under the impression that you water washed your bio, so your residue can't be anything to do with glycerol.
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Yes I do ... 5% glycerin wash, acid wash and two or three water washes all with Frankinpump.
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Just had a quick chat with a professor at Southampton Uni and he pointed me in the direction of this:
https://www.metrohm.com/en/products/stability-measurement/rancimat/
Rancimat, as you might guess, measures rancidity - so our theory that the nasty smell from the bottom of old drums is from oxidised biodiesel holds out.
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Same company that made my Karl Fischer Water auto titrator (Metrohm KFD 758)