Ambient processing

[dgs]

What sort of compressor and particularly pressure are you using, I might give it a go.

Its a 50 year old little broom wade (like the one Tony brought to the bbb several years ago) It puts out 2 to 3 cu ft/ min. Pressure will be low, <10psi.

[countrypaul]

Going back to the original cause for this thread, looks like some process has taken place in some barrels! 2 had a layer of what I presumed was methanol/catalyst , but less than half the original amount, the other two appeared to have absorbed all the methanol, one seemed to have thinner oil than it started with (which woud be the case if some was now bio), the other looked as though it was brown cottage cheese (not sure if any process has occured. All barrels got another stir, but I did not have the chance to carry out a Warnquist test.

[Dickjotec]

What sort of compressor and particularly pressure are you using, I might give it a go.

Its a 50 year old little broom wade (like the one Tony brought to the bbb several years ago) It puts out 2 to 3 cu ft/ min. Pressure will be low, <10psi.

Thanks for that might find something  to try.

[DavidA]

This may not be the right place for this, but here goes.

I have been doing a few of my little 2 Litre 'test' batches recently. No problems and they have found their way into the fuel tank.
But I made a couple of 2 litre tests over the last two days.

The first one titrated at four Gram.
So I used 200mL Meth and 16 gram NaOH to make up the methoxide. (5+titration per litre x2).
The oil had been boiled dry. and was around 55C when I added the methoxide. Did my usual shake mix over the next hour and left it overnight.
In the morning there appeared to be about the right amount of glyc drop-out. So I did a 10/90 test and so far nothing has dropped out. So it looks good.
However.
Today I did another 2 litre test using the same dried oil. But I thought 'maybe I'll do a sort of two stage reaction this time. That way I will be able to try the drop-out calculation for the second stage.
So I used 190 mL per litre Meth but only 5 g per litre NaOH to make the methoxide.  Reasoning that was pretty much what is done in the two stage no-titration process anyway.
The oil was, again, at around 55C, Shake up procedure was the same.
Then I left it on the bench and went inside.
Coming back half an hour ago I fine a bottle of very thick paste. No drop-out.
I have added methanol to bring it up to 200ml/Litre.  Stood it in a bowl of hot water then given it a good shake. I'm hoping that I will get some sort of glyc drop-out so I can carry on with a second stage.

What do you think caused this thick paste to form ? I suspect the low temperature in the shed, but Dave (dsg) works at ambient and this doesn't happen to him.

[dgs]

I do use an ambient reaction but use a mixed 50/50 catalyst. Using just Sodium with an ambient reaction would probably cause trouble.

I don't know why you have thick paste unless its the temperature however the absence of glycerol is probably that you didn't even add enough sodium (if my reading of your post is correct) to neutralise the ffa's so no transesterification would have taken place.

EDIT Reading your post again Dave you say the oil titrated at four grams, do you mean 4mls of 0.1% NaoH. If so then to do a 2 stage on your 2nd sample surely you needed to add titration amount for 2 litres= 8 gms + say about 3.5gms NaOH/ litre which should be 15gms NaOH, not the 10gms you added. Using the 19% methanol is more than sufficient.

[DavidA]

Dave,

The reasoning behind what I did was that, in the no-titration process, you start out with a low amount of catalyst (around 4 Gram/litre, then use the drop-out to calculate the amount of catalyst required for the next stage.
As the normal titration method always requires titration amount + the base amount (4-5 G/Ltr) I would just initially use the base amount for  the first stage Then calculate the next stage from the drop-out.
At least that was the plan.

  After last night's re-treatment today I have about 400 mL of bio sat on top of a thinner solution that looks as if it may simply be unreacted oil. No discernible Glyc drop-out.

I'll try a second stage and see what happens.

[countrypaul]

If you have merely netralised the FFA and had little to no transesterification then you will have produced soap but little to no glycerol. The soap is normally present largely in the glycerol, so with no glycerol present it will be largely in the oil which could result why you appear to have a thick paste. The low temperature will make the paste appear thicker especially if near the gel point of the oil.

Adding the aditional methanol could have helped thin things down slightly, but bearing in mind that the veg oil is not miscible with methanol, the top layer could be largely methanol with whatever would dissolve in it, any thing that has transesterified, impurities that would normally be in the glycerol, and glycerol itself in the methanol.

The second stage should result in transesterification moving much further along and glycerol dropping out.

You could try adding only have the amount of caustic you were planning for your second stage which should result in significant reaction but is unlikley to get anywhere near complete, but should result in some glycerol dropout.

[dgs]

If you have merely netralised the FFA and had little to no transesterification then you will have produced soap but little to no glycerol. The soap is normally present largely in the glycerol, so with no glycerol present it will be largely in the oil which could result why you appear to have a thick paste. The low temperature will make the paste appear thicker especially if near the gel point of the oil.

Adding the aditional methanol could have helped thin things down slightly, but bearing in mind that the veg oil is not miscible with methanol, the top layer could be largely methanol with whatever would dissolve in it, any thing that has transesterified, impurities that would normally be in the glycerol, and glycerol itself in the methanol.

The second stage should result in transesterification moving much further along and glycerol dropping out.

You could try adding only have the amount of caustic you were planning for your second stage which should result in significant reaction but is unlikley to get anywhere near complete, but should result in some glycerol dropout.

Paul, it isn't often that I read technical posts and think "Ah, I never thought of that" but your 1st paragraph is something totally logical that has never struck me before, well thought out.

[DavidA]

Thanks for the replies.

I mixed up about 20 mL of Meth with about 4 gram of NaOH. Warmed the oil back up to 50C,. Added the methoxide and gave it a good shaking over the next hour. Then let it stand overnight.
This morning I have some thing that looks like a normal brew but has less glyc dropout (as expected).
A 10/90 test shows 1mL dropout  I take that as 10%.

So I think my next move is to mix 10% of my original base NaOH (10% of 5  gram/litre x2)=1 gram with a bit of meth and mix thoroughly.

Am I right ?

[dgs]

Looks ok to me Dave.

[DavidA]

Nice to know that I am getting somewhere near.

But It would not be me if everything went to plan,
As I was about to carry out the last stage, I had to go collect my daughter from the Supermarket. And it was snowing heavily.

So, did the trip, dumped in the methoxide. Then realised that in the earlier confusion I had forgotten to remove the glyc from stage 1.

So it became a three stage project.

A 10/90 test produced 0.5 mL of dropout.
Mixed up a drop of meth and 0.5 gm of NaOH and (after removing the glyc this time) proceeded as before.

I do see a bit of glyc dropping, but will leave it until morning to do the , hopefully, last 10/90.

[dgs]

Nice to know that I am getting somewhere near.

But It would not be me if everything went to plan,
As I was about to carry out the last stage, I had to go collect my daughter from the Supermarket. And it was snowing heavily.

So, did the trip, dumped in the methoxide. Then realised that in the earlier confusion I had forgotten to remove the glyc from stage 1.

So it became a three stage project.

A 10/90 test produced 0.5 mL of dropout.
Mixed up a drop of meth and 0.5 gm of NaOH and (after removing the glyc this time) proceeded as before.

I do see a bit of glyc dropping, but will leave it until morning to do the , hopefully, last 10/90.

Well done. Yes, you have have to careful removing the glycerol, it likes to 'eat up' chemicals.  At least if you can glyc wash with it you will reclaim most of the chemicals. You will have to start using KOH or at least a blend of sodium and potassium, it is so much easier.
 

[DavidA]

I use NaOH as I was given a 25 kilo bag of it (which I keep very carefully sealed) some time ago.Though I do agree that KaOH is easier to use.
Anyway, I can report that this mornings 10/90 test resulted in zero drop-out after an hour with the sample being held at close to 20C. So I call that a result. It just remains to wash it.

I was thinking about the situation that caused my problem. The paste.
And that adding some meth helped to clear it.

Is there a definite ratio of NaOH to Meth that one mustn't exceed with the two stage no titration method ?

If the 5 Gram/200 mL brought things pretty close to turning to jelly it would appear that it's not safe to pass 4 gram/ 200 mL for the first stage.

I am aware from experience that too much caustic will turn things to jelly very quickly.

[Tony]

10% methanol isn't a lot, I've had problems with the glycerol not dropping out at that kind of level.

I've never really thought about why, I always put it down to the liquid not being "thin" enough.  But then I have a scummy dregs drum that put all the nastyness from the bottom of oil collection barrels into - and to that I add just glycerol, and stir it in with a stick.   No heat.  That seems to always separate out, but then I do leave it standing for weeks before skimming some good liquid off the top.

[DavidA]

Tony,

I am referring to 200 ml/Litre.  That's 20%