Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: dgs on December 12, 2015, 01:06:19 PM
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Having done many ambient reactions, this link recently came up on infopop. I've heard of using quicklime before as the catalyst but not for drying the KOH type methoxide.
It was developed by Mark Imisides
http://biodiesel.infopop.cc/ev...057046543#1057046543
Sorry folks, link won't work, will see what I can do.
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/1057046543?r=1057046543#1057046543
Thats better.
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Hydrated lime is available in the UK from most builder's merchants.
Its added to mortar renders.
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Hi Willbuild,
Is hydrated lime the same as quicklime (calcium oxide)
I think this process yields effectively AKM. If it works It seems very good, although I'm a bit puzzled why this method should work with ambient reactions better, except for using less methoxide. Time will tell.
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I read near the end of the article that hydrated lime was not easily accessible in Australia but that you also use quick lime. Which is easily accessible.
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I read near the end of the article that hydrated lime was not easily accessible in Australia but that you also use quick lime. Which is easily accessible.
I think it's the other way round. Not that I'm an expert, this from Wikipedia.
Quicklime is ... Calcium oxide ... CaO ... also known as burnt lime, when mixed with water forms hydrated lime.
Hydrated lime is ... Calcium hydroxide ... Ca(OH)2, also known as Slaked lime or builders' lime and is what's used in the building industry for mortars and renders (so readily available)
Daves link to Infopop concerns Quicklime. Therein is another link to using Hydrated lime as a catalist ... Infopop thread ... http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/3397000933 (http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/3397000933) Some experimentation seems to have been done by taralec who I beleive is a member on the VOD and known to Keef on here. From a very quick read he seems to have had some success with the method.
For my part I've tried using Hydrated lime to dry methanol. My efforts weren't very scientific and didn't appear to work, maybe Quicklime would have worked better.
It looks very interesting, just wish I could understand it all!
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I used quick lime years ago to make white wash in southern Spain.
We would pour 80 litres of water into an oil drum and add quick lime rocks one at a time whilst stirring and adding another30 litres of water to 6 to 8 kg of quick lime.
The heat generated would make the mix boiler, the white wash would kelp the heat for several days.
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In the thread I linked to is a pdf download by Jon T who sumerised the method ...
http://api.viglink.com/api/click?format=go&jsonp=vglnk_145000806081914&key=9bdcc5c751999fa8170ff838157bab8f&libId=ii4h435k0100075t000DA5u991692&loc=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F3&v=1&out=http%3A%2F%2Fwww.mediafire.com%2Ffile%2F8u269y78y55w5we%2FHydrated%2520lime%2520catalyst.pdf&ref=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F2&title=new%20process%20for%20making%20biodiesel%20-%20Topic&txt=Hydrated%20Lime%20Catalyst (http://api.viglink.com/api/click?format=go&jsonp=vglnk_145000806081914&key=9bdcc5c751999fa8170ff838157bab8f&libId=ii4h435k0100075t000DA5u991692&loc=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F3&v=1&out=http%3A%2F%2Fwww.mediafire.com%2Ffile%2F8u269y78y55w5we%2FHydrated%2520lime%2520catalyst.pdf&ref=http%3A%2F%2Fbiodiesel.infopop.cc%2Feve%2Fforums%2Fa%2Ftpc%2Ff%2F719605551%2Fm%2F3397000933%2Fp%2F2&title=new%20process%20for%20making%20biodiesel%20-%20Topic&txt=Hydrated%20Lime%20Catalyst)
He seems to use a massive quantity of methanol though.
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I used quick lime years ago to make white wash in southern Spain.
We would pour 80 litres of water into an oil drum and add quick lime rocks one at a time whilst stirring and adding another30 litres of water to 6 to 8 kg of quick lime.
The heat generated would make the mix boiler, the white wash would kelp the heat for several days.
I bought a couple of sacks of premixed lime mortar (assume it was hydrated lime mixed with sand) from a specialist company on the South Downs, to do some pointing. It was fantastic stuff to use, way superior to cement mortar and has set like rock, not at all powdery.
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I've read all the links Julian, most interesting. Giving this some thought I think that the greatest advantage of all these methods would be using quicklime (CaO) to dry the methoxide. Using either quicklime or Slaked lime as the catalyst for the main reaction seems a bit of a false economy. After all, using KOH equates to 1 pence/litre to the cost of making biodiesel.
It maybe that when decanting the methoxide from the fines, these could be put into some sort of filterbag and 'hung' in the processor to help with the reaction.
In anycase the KOH is cheap and I now use a maximum of 12.5% methanol (added) plus what I recover from the glycerol. So if the dry catalyst reduces soap production and increases yield then my process will be another step more efficient.
I've just got to find some quicklime and I'll give it a go, Maybe a 70 to 80 litre batch in my small 120 litre processor.
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I discussed this with chemist neutral a few years back when using lime on my strawbale buildings and slaking it ourselves into lime putty, he told me he didn't think it would work and gave good reasons that I forget now.... polarisation maybe..dunno..
anyway I tried adding some to methanol and it didn't mix well at all, tried mixing it in wvo, it clumped and fell to bottom, removed some water but was a right mess to remove, I never got any further as its highly corrosive and you cannot keep it in the open air for long and it was about the same price as NaOH and worse to work with and I wasn't really getting anywhere fast. It was quicklime in powder form rather than freshly made lumplime/quicklime which would be even more of a nightmare to use.
I've still got lime render and lime putty up the field but no quicklime
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Thanks for that Chug.
I'm picking up some quicklime on wednesday which I will use to dry the next lot of KOH methoxide. I will report in due course.
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Haven't finished all the pre-tests with this method but thought these results are interesting so far.
Reclaimed trinity methanol-2600ppm water.
400 mls of above + 50gms KOH the test at present shows 25000ppm (2.5%) and still rising.
Have to go out now for rest of day but will post tomorrow with the final result of the methoxide water plus what it is going to be after the CaO is added.
25000ppm, Wow, still can't quite get my head around that.
If this test is correct and we assume the oil was totally dry before adding the methoxide, then at the normal concentrations of added methoxide we are adding around 4000ppm water to the mix!
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I have now finished the water tests regarding potassium methoxide drying, Here are the results;
Trinity Reclaimed methanol 2600ppm
methoxide, 400 mls of trinity methanol plus 50gms KOH 31,200ppm (3.12%)
I added 50gms of quicklime to this and stirred for 5 mins then left to settle, 22,200ppm (2.22%)
I then added 100gms of quicklime to 250mls of methoxide, freshly mixed at same ratio as above, this was in a jam jar and I shook the hell out of it for 10 mins then left for the CaO to settle, 4,200ppm (.42%)
So it does seem to work, although not getting the methoxide totally dry. I have a feeling that the 1st test probably wasn't mixed enough.
The most suprising thing is the original water content in the methoxide, 3.12% The last test showed a reduction of water by something like 85%
Next thing would be to try this in a 'real' process.
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Good work, Dave!
How will you replicate the vigorous mixing at full scale ... bit dodgy pumping methoxide to mix it?
Will this process work with NaOH?
Do you think it would work for drying bio and would it be economical compared to heating?
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I think I will mix the methoxide and lime in cubies, then leave it to settle and pour off the lime-free methoxide. To reclaim the methoxide slurry from the cubie bottom I suppose a filter bag arrangement would be best.
Julian, there are still lime 'fines' left in the methoxide, so it isn't clear even after 24 hours. During the process I'm sure most of it will be removed either with the glycerol or by water washing, but using it to dry the bio would present a problem. The fine bits left in suspension in the methoxide look to me as if they would easily go through a 1 micron filter.
I'm sure this process would work with Sodium Methoxide.
I know Paul did a calculation re the amount of water formed when KOH methoxide is mixed but I don't know how my results compare with the theoretical amount.
I have just found the figures that paul worked out, and adding 50gms of KOH into methanol (assuming the methanol was water free) would yield 16gms of water, so in 400mls of methanol that gives 4%. My result was 3.1% so it's not that far away. Doing a water test with the s/b with water so high means using a very small sample size so the accuracy of the test is less.
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If you add 50g of KOH then that is equivalent to adding 50*18/56g of water, which to 400ml of methanol (assume density of 0.8) gives a total mass of 450g with 16g of water, or 3.57% or 35700ppm.
To absorb the water from 50g of KOH you would need 50g of CaO (coincidence since MW of CaO is also 56). In practice to ensure the methanol/methoxide is dry you would want an excess.
My guess is that calcium methoxide is largely insoluble in methanol, but I can't actualy find and solubility information about it easily.
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Good work dgs, keep it up!
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I mixed up my first lot of methoxide today, ready for the process. 2 cubbies, 15 litres methanol in each + 1kg KOH, followed by 1.5kgs CaO. Shook both up every 10 mins for the first hour whilst still warm.
The 1kg in 15 litres is a little stronger than normal, so if I have to add a little more methanol it's not a problem. The no no is to add more KOH so that more water is produced.
If this works I have an oid green fuels 60 litre methoxide mixing tank with the hand stirrer which I will set up to mix the methoxide chemicals in. What a messy job it is using the quicklime.
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yeah the mess was a lot of the reason I gave up.
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last night I mixed two teaspoons full of quicklime into a jam jar with finished bio in it. The water in this bio had been checked at 240ppm. I left the mix overnight for the lime to settle and this morning checked the top bio layer for water. It was zero. Maybe it's a little ambitious to say zero but there was no reading on the s/b. The pressure gauge was still on the zero after 4 hours.
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last night I mixed two teaspoons full of quicklime into a jam jar with finished bio in it. The water in this bio had been checked at 240ppm. I left the mix overnight for the lime to settle and this morning checked the top bio layer for water. It was zero. Maybe it's a little ambitious to say zero but there was no reading on the s/b. The pressure gauge was still on the zero after 4 hours.
Sounds promising, but seem to use quite a lot of lime.
Do you think it would work with less and did the bio clear OK?
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I'm sure it would work with a lot less, the top bio layer that I tested still had a lot of lime in it.
If we say that finished bio which was very slightly dried had (let's say) 900 ppm water, so from the figures that Paul gave something like 4gms would be sufficient to dry 1 litre to zero, providing it was well mixed. I will repeat the test after Christmas with far less CaO and see if the bio will clear and test for water.
the test jar and indeed cubies of mixed methoxide and lime now have clear methoxide layers, although it has taken 5 days to clear. As (I assume) the sg of bio is higher than mixed methoxide the lime would take much longer to settle in bio.
I've been wondering how to quantify the results when I do the 1st process with the dried methoxide. Soap testing may tell us something but of course every batch is different. So giving it some thought maybe yield and glycerol volume would be a good indication.
Julian, I'm finally ready to do some sensor water tests and will get on with these after Christmas.
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Might be worth comparing it to some bio made with commercial ASM from the same batch of oil. The differences shouldbe similar to that you get when using KOH rather than NaOH, but any thing else might be related to for example lime left in the mix. Calcium soaps are generally very insoluble and so should drop out quite readily if there is an lime present.
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I have now done my first reaction using the dried methoxide. The results are encouraging.
I intended to post this yesterday but our internet has been down for the last 24 hours due to the flooding in York.
As this reaction was with poor oil for the central heating the comparison to a 'normal' process is difficult, however the overall result is a lot better than I usually get with this oil.
After glyc pre-treating (no enhancement) with glycerol that had been used once (and some twice) before I suspect the oil still had a small titration.
I used 7.5gms KOH/litre and a total of 13.5% methanol over 2 reactions (200 litre batch 10/90 was 0.2mls dropout, OK for c/h)
So 28 litres of methoxide added, 21 litres of glycerol extracted without de-mething. Volume in processor 210 litres. Soap, 20 hours after last reaction 1700ppm (on my process this is usually around the 3000ppm level.
I will repeat the process with dried methoxide when I do the next batch for road fuel.
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Good stuff Dave,
Was the lime still in the methoxide, or did you manage to remove it?
and 28L in 200 is 14%
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Hi Chug,
There was some lime in it but not much, I decanted the methoxide into another cubbie and left most of the lime behind.
There was 27 litres of methanol and 1500gms of KOH in total, which made the methoxide volume closer to 28 litres.
I don't normally take too much notice of how much KOH I use for the reactions for the c/heating bio and as long as the reaction is 90% or over it's OK, but I'm pretty sure it usually takes more that 7.5gms.
Do you think that leaving some lime in the methoxide has reduced the KOH amount, or it was less because of the reduced water.
I hope to mix the methoxide/lime for the next road fuel reaction tomorrow (in the old 60 litre green fuels methoxide mixer if I can get all the years of crud off it)
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I guess the only way to tell if residual lime is affecting it, or less water, is to compare it with a batch with lime removed.
You seem to be getting better results than I did when I tried it I seem to remember a few messy weeks with not much benefit, although with the quicklime I used there was question on how fresh it was, it'll be good if you get a handle on it.
Keep us posted.
BTW is it powdered quicklime you are using?
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It is powdered Chug, really fine stuff, gets everywhere.
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Be really careful geez, it can burn the fine hairs in your lungs if breathed in.
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Thanks Chug,
will do, I have a full face mask with filter that I will use and preferably do it outside. Was cleaning the 60 litre tank outside until a few mins ago, now rained off!! bugga.
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Happy New Year to you all.
OK, I've now completed the first process of road fuel with the lime dried methoxide.
I used 200 litres of my best oil, it had been glyc washed (no enhancement used for this) and a 10/90 test showed 9.5mls dropout. I'm not sure what this actually means as I have done many 10/90's on untreated oil and many times had a result of less than 10mls.
I ended up doing 3 reactions to get a clear 10/90 pass. Starting temperature was about 32degs and end temperature just under 40degs (the pump heats up the mix without the immersion)
Total methanol used 24litres. Total methoxide volume nearer to 25 litres. Total KOH used 1540gms (7.7gms/litre)
Glycerol extracted 16 litres. I don't think there is any doubt the reduction in glycerol volume is because of the vast reduction in soap level.
I have now finished de-mething the batch and I am left with 204 litres before water washing. There is still some lime in suspension, so I will have to see how the washing goes.
Although the KOH used isn't excessive it isn't particularly low, it is certainly higher than I thought it would be, however the process has used a minimum of methanol, 12% (the expensive part)
After looking at the cubies of methoxide I mixed for the last batch, about 80% of the bottom settled layer of lime has gone as solid as a brick, presumably the part that has reacted with the water, now Ca(OH)2
After seeing this I decided not to use the small 60 litre tank to mix the methoxide, I had visions of trying to remove the solid lime out of the cone. So I will continue to mix in cubies and discard when the solid layer gets too deep.
The quick lime I bought was £10 from a local company and this will dry the methoxide for at least 5 processes, so it adds 1p/litre to the bio cost. Having said that, as there seems to be an increase in yield there is probably a net gain.
I am going to set up my smaller 120 litre processor for the next 2 batches and use the same oil from the storage tank. I will do 2x identical processes, one with the dried methoxide and one with normal. This should give a better comparison of exactly how much better the process works.
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Excellent and interesting work, Dave.
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Thanks, Glycer-rides,
David Shinn is also trying this method and he will make a post on here in due course.
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was the soap ppm level similar to 1700 before?
and 21 ltrs glyc last time with 2 stage process, 16 ltrs this time with 3 stage process, I don't think a third stage would have produced 3 litres glyc on the previous batch do you, so showing the difference between good oil against poor oil
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I think you are correct Chug.
Regarding the soap levels, I have done literally hundreds of soap tests over the years and this latest batch was very high at >5000ppm after the last reaction and today 3200ppm. But I don't think it's soap that I am testing. I think the alkalinity I am titrating is due to the suspended lime in the bio.
The reason I say that is when I de-methed I usually get about 6 to 7 litres of glycerol/soap falling after a few hours. With this batch I got 1 ish litres.
Also David Shinn (we PM each other all the time re this process) has reported that he has had the same minimum amount of glycerol fall after de-mething and is in the process of pump washing with no emulsions.
I think David was probably a little more carefull to reduce the amount of lime added with the methoxide than I was. It can be avoided by having enough methoxide mixed so that the bottom layer isn't poured in. I assume this dried methoxide will 'keep' for a few weeks.
Julian asked could the lime be used for drying the finished bio. Whilst there is little doubt it does dry it very effectively if the lime was left to settle it would take a long time. Or a centrifuge maybe.
I am just hoping that the water washing removes all traces of the lime.
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Thanks, Glycer-rides,
David Shinn is also trying this method and he will make a post on here in due course.
Hello!
I am a friend of dgs from Leeds, and as he says, I will post my own results when I have finished pump washing and drying my batch. it will be two or three days, as I am now back at work.
Best wishes,
David
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Welcome David, are you doing similar sized barches to Dave?
I tried some experiments with quicklime a few years back but only 25 L batch sizes, hats off to Dave for going in on full size batches.
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Another possibility if there is lime left in the mix, is that the soap being formed is calcium soap which tends to be very insoluble and would precipitate out much more easily than potassium or even sodium soap. If this happened, then you might be left with much less soap/glycerol present than normally expected - which could be a partial explanation for why you seem to get so little glycerol. Also calcium soap due to its insolubility is much less likely to act as an emulsifier.
Another factor to bear in mind is that calcium is bivalent, so whilst one mole of quicklime weighs about 74g it will require 2 moles of acid to neutralise it - I don't know how you are testing and calculating the soap content, but this could cause significant discrepancy. For example, if you are relying on a mw of 39 for potassium but actually have calcium (mw 40) then you will be nearly a factor of 2 out (due to calcium being bivalent).
Paul
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Thanks for that Paul.
I calculate by multiplying the titration by 320 so does this mean the soap (if it is calcium soap) is about half of the amount calculated.
I will put up a full post when I have totally finished the batch, but after drying it is still cloudy at the moment. For the last 2 hours of the drying cycle I added some magnesol to hopefully remove anything in suspension. I know magnesol can be a difficult thing to remove but when it is all settled (i will leave it 2 days) Then I will centrifuge it and hopefully end up with a clear product.
The water washing went really well, hardly any soapy water and no mono's at all.
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I have now 'sort of' completed the batch. I'm afraid to say that things haven't gone well. I will explain.
The water wash went "seemingly" very well. Even after the 1st wash there was hardly any soapy water. I washed 4 times and on the 2nd wash the water was clear. I dried the batch and noticed before heating that there was something suspended in the bio. After drying the bio looked the same ( like bio with lots of suspended water) I centrifuged 70 litres of it and although the centrifuge caught what looked like caramel coloured soap/glycerol it did not separate it hardly at all. As the density of this contaminant seems to be the same as bio the centrifuge won't work.
It seems that whatever it is, it is not water soluble and has virtually the same density as bio.
I did a small test filtering it through woodchips and although not clear the biodiesel clarity has considerably improved.
At the moment it is all (70lts) filtering through some fresh oak chips and it seems as though it is now clear.
I intend to keep filtering it until the soap test is in spec. I've not checked it yet.
So, some questions. What is this contaminant, is it as Paul suggests and is calcium derived soap/glycerol which seems difficult to remove. Why did it form in the 1st place, was it me not being careful enough so pouring some lime in with the methoxide, or just adding too much lime in the 1st place. Any thoughts would be appreciated.
I think David, although having problems is having more success than myself.
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After filtering it twice through oak chips (once and then once through another tub with new) it has come out OK. In fact it is beautiful and clear. Soap test is zero, so I'm sure it has also removed any glycerol present.
The chips seem to be the only thing to get rid of the suspended calcium soaps as I have found water washing, magnesol, centrifuging doesn't work.
To try and get to the bottom of this I have today finished processing a new batch. I used (roughly) 25% of the lime dried potassium methoxide and 75% ASM. I was careful not to tip any lime out of the dried methoxide cubie. The last 10/90 showed a clear pass, but at the bottom of the tube, is sure enough a residue that I would suspect is calcium soap. I am not worried now as I know what to do to remove it.
The batch is de-mething and my intention is to then let it settle for several days, running off the glycerol in ever decreasing amounts and then without water washing or drying just run it through the oakchips. I will then test for soap and water.
I'm just wondering about the calcium soaps. I wonder if the massive overdose of CaO I gave the methoxide
has produced a lot of calcium methoxide. If this is the case if the minimum of CaO was used to dry the methoxide, without it reacting with the methanol it would result in dry methoxide without it being able to produce the calcium soaps. Maybe Countrypaul would know.
Chug, when you tried this did you get the cloudy bio due to the calcium soap.
As usual using the dried methoxide + ASM has resulted in a vast decrease in glycerol volume.
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Thanks for that Paul.
I calculate by multiplying the titration by 320 so does this mean the soap (if it is calcium soap) is about half of the amount calculated.
I will put up a full post when I have totally finished the batch, but after drying it is still cloudy at the moment. For the last 2 hours of the drying cycle I added some magnesol to hopefully remove anything in suspension. I know magnesol can be a difficult thing to remove but when it is all settled (i will leave it 2 days) Then I will centrifuge it and hopefully end up with a clear product.
The water washing went really well, hardly any soapy water and no mono's at all.
Dave,
OK, your calculations are exactly as per the wiki (forgot to check that earlier) however this may be a little more complicated than anticipated. Rather than using 320 you should be using 602 for calcium soap. This will give you a techinically correct value for calcium soap, however it will be only half the value it would be for sodium or potassium soap due to calcium being bivalent. Therefore to compare the soap level in terms of the amount of fatty acid present in the soap you should double the figure you then get for calcium. It appears the original ASTM definition is for the amount of sodium or potassium in terms of ppm and this has been extrapolated to ppm of soap. Using the value I gave would give you the correct value for calcium (not sure if that is in the ASTM standard).
Looks like I may have to trawl through infopop to find the original maths and assumptions behind them to fully understand why the figures supplied are used. After correcting the figure above (602 for calcium) it became obvious that the oleate salt is used for the soap calculation. Should not matter too much since everyone uses the same figures, but could possibly be out a significant amount if someone is using say beef fat. However the test is actually for sodium/potassium rather than soap per se so referencing a standard soap makes a lot of sense even if it is a little misleading in terms of what it is now used for.
Sorry for the earlier mistake (I subtracted KOH MW rather than just K).
Paul
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A simple test to see whether there is calcium present would be a flame test on some of the bio (or better still the contaminants). If you get a piece of nichrome wire and heat it in a hot flame such as a blowlamp it should glow red and the flame may go from blue to orange. If you dip the wire into the bio/contaminant then put it in the blowamp flame with luck it will show up differnt colour. Green would indicate copper present, violet/purple would indicate potassium and brick red would indicate calcium present (for reference sodium would be orange and therefore almost impossible to distanguish from background). Not sure if esting the wood chips would be valid but try some unsed ones and if they just come out orange then try some used ones and look for the distinct colours.
Another test you might try with the contaminated bio (you did keep a sample didn't you ;D) is to wash it with some dilute hydrochloric acid (brick acid), if it is calcium soap, I would expect most of it to get removed as the soap goes back to ffa and the calium gets washed out as calcium chloride. If you use sulphuric acid it will produce calcium sulphate which is not water soluble (and I doubt bio soluble) but might be so fine that it makes the bio appear cloudy.
It is possible that in adding the quicklime to the KOMe to take out any residual water that some of the quicklime is converted to CaOMe that may be methanol soluble. Again you could try a flame test and the solution, but be especially careful if you do as methanol fires are extreme. So a small sample bottle near the flame so that you can dip the cold wire into it at most. the colour might also be difficult to be sure of as there will be significant colouring from the potassium.
Obviously the flame test is not quantitative, but a negative for calcium might help rule that out.
Another obvious feature is that because the oil has been glyc washed and hopefully has a titration value very close to zero using almost anhydrous methaoxide for the reaction will result in virtually zero soap production. Any soap present in the oil from the gly washing process could still be converted from potassium to calcium soap however.
Paul
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Thanks for that Paul, I will do a flame test tomorrow and report.
I still have 2x cubies of the original 110 litres that I set aside for the heating. I noticed today that one has now clear-ish bio and a small layer of off white deposit in the bottom.
I have ended up woodchip filtering the 90 or so litres from this batch. It is now filtering for the 3rd time and the bio is lovely and clear with zero soap.
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If you can test some of that white deposit in the bottom I would be very intrested in whether that is calcium soap.
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yes Dave, I tried washing to remove the lime from bio after use and demeth n settle and multiple filtering but not much improvement if any then I spilled some of the lime in me toolbox and I remember whilst clearing it up and issuing profanities thinking this was to try and find an easier and better way and it aint working for me so that was when I gave up.
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Sorry to hear that Chug but at least I know the lime (or whatever) isn't only a problem to me. On the one hand I want to call a halt to this, but now realising all the water that I'm dumping into the processor with the potassium methoxide I will try to get it to work. It does seem that the woodchips are the answer but talking to David (who has persevered a lot more than I did) with water washing it seems to be working for him.
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Seen this reference on infopop regarding calcium soaps http://biodiesel.infopop.cc/eve/forums/a/tpc/f/9411061471/m/276102893
Not actually backed up with any evidence though.
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I have just completed the flame colour test as recommended by Paul. I dipped the nichrome wire in the cloudy bio and indeed after a second or so the flame turned a brick red colour.
Having left the 2x cubies i have left of the 1st batch a few days, the Calcium soaps do very slowly settle to the bottom.
Just giving this method a little more thought, instead of removing/pumping the bio out of the settling tank into cubies, then dry washing them through woodchips, an 'in tank' woodchip filter could be set up and the bio just recirculated through the woodchips in the tank. A very slow pump could be used (something around the 5lpm volume) and just left to pump until the soap showed zero. As the woodchips work with warm or cold bio there is no reason why both the filtration and drying cycles could not be done simultaneously. This is a similar method to the one IMB employs, just hanging his drywash basket in the processor after de-meth and settling.
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All may not be lost after all!
Mark imisides has just seen that there has been some activity in his oid thread on infopop and says he will post a slightly modified method when he has time.
Here is his post;
Minder
Member
posted February 13, 2016 01:55 AM
quote from dgs -------------------------------------------------------
In this respect this method worked extremely well. However, I found one large drawback, the process produces some calcium soaps. Not a great deal, but they are very difficult to remove.
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It's amazing what you find when you Google your name. I haven't visited this forum for some time, and there have been several pages of discussion since I last visited.
I'll plough through them when I get a chance, and answer as many questions as are appropriate. In saying that I face the problem that most of you don't understand much chemistry (exception is WesleyB). This is complicated by the fact that a couple of self-styled experts have popped up who think that they do, and have done nothing but confuse people with their uninformed comments.
The bottom line is this - the explanations I have given will make perfect sense to a chemist. If they don't, then I'm afraid I don't have the time or inclination to conduct online chemistry tutorials. The method was written for the layman. All you have to do is follow the method and it will work. I'll happily answer any questions directly arising from the method, like this one.
Also, I have now simplified the method even further, but I'll get to that later.
To answer this specific question, if you got soap in the batch, it's because the oil wasn't dry. This method is anhydrous, and will work best with dry oil.
I once got lazy with this, but never again. I had a batch that I knew had some water in the oil, but went ahead anyway. The result was that the method didn't proceed at room temperature - a bit of a problem when you make 1000L at a time.
So I whacked a water heater in it overnight, and by the time the temperature got to about 30C it commenced.
Afterwards when it settled there was a yellow layer of soap sitting on top of the glycerol, which I guess is what dgs is referring to. The problem that this caused was it greatly increased the settling time when I tapped off the raw product into one of my settling tanks. Never again.
Shortly I'll repost my method modification. Also, for those of you living in Perth WA I'll be doing a public demonstration of this method soon.